First Principles
by Herbert Spencer

Part I

The Unknowable

Chapter 1

Religion and Science

§1. We too often forget that not only is there "a soul of goodness in things evil," but very generally also, a soul of truth in things erroneous. While many admit the abstract probability that a falsity has usually a nucleus of verity, few bear this abstract probability in mind, when passing judgment on the options of others. A belief that is proved to be grossly at variance with fact, is cast aside with indignation or contempt; and in the heat of antagonism scarcely any one inquires what there was in this belief which commended it to men's minds. Yet there must have been something. And there is reason to suspect that this something was its correspondence with certain of their experiences: an extremely limited or vague correspondence perhaps, but still, a correspondence. Even the absurdest report may in nearly every instance be traced to an actual occurrence; and had there been no such actual occurrence, this preposterous misrepresentation of it would never have existed. Though the distorted or magnified image transmitted to us through the refracting medium of rumour, is utterly unlike the reality; yet in the absence of the reality there would have been no distorted or magnified image. And thus it is with human beliefs in general. Entirely wrong as they may appear, the implication is that they originally contained, and perhaps still contain, some small amount of truth.

Definite views on this matter would be very useful to us. It is important that we should form something like a general theory of current options, so that we may neither over-estimate nor under-estimate their worth. Arriving at correct judgments on disputed questions, much depends on the mental attitude preserved while listening to, or taking part in, the controversies; and for the preservation of a right attitude, it is needful that we should learn how true, and yet how untrue, are average human beliefs. On the one hand, we must keep free from that bias in favour of received ideas which expresses itself in such dogmas as "What every one says must be true," or "The voice of the people is the voice of God." On the other hand, the fact disclosed by a survey of the past that majorities have usually been wrong, must not blind us to the complementary fact that majorities have usually not been entirely wrong. And the avoidance of these extremes being a pre-requisite to catholic thinking, we shall do well to provide ourselves with a safeguard against them, by making a valuation of opinions in the abstract. To this end we must contemplate the kind of relation that ordinarily subsists between opinions and facts. Let us do so with one of those beliefs which under various forms has prevailed among all nations in all times.

§2. Early traditions represent rulers as gods or demigods. By their subjects, primitive kings were regarded as superhuman in origin and superhuman in power. They possessed divine titles, received obeisances like those made before the altars of deities, and were in some cases actually worshipped. Of course along with the implied beliefs there existed a belief in the unlimited power of the ruler over his subjects, extending even to the taking of their lives at will; as until recently in Fiji, where a victim stood unbound to be killed at the word of his chief himself declaring, "whatever the king says must be done."

In other times and among other races, we find these beliefs a little modified. The monarch, instead of being thought god or demigod, is conceived to be a man having divine authority, with perhaps more or less of divine nature. He retains, however, titles expressing his heavenly descent or relationships, and is still saluted in forms and words as humble as those addressed to the Deity. While in some places the lives and properties of his people, if not so completely at his mercy, are still in theory supposed to be his.

Later in the progress of civilization, as during the middle ages in Europe, the current opinions respecting the relationship of rulers and ruled are further changed. For the theory of divine origin there is substituted that of divine right. No longer god or demigod, or even god-descended, the king is now regarded simply as God's vicegerent. The obeisances made to him are not so extreme in their humility; and his sacred titles lose much of their meaning. Moreover his authority ceases to be unlimited. Subjects deny his right to dispose at will of their lives and properties, and yield allegiance only in the shape of obedience to his commands.

With advancing political option has come still greater restriction of monarchical power. Belief in the supernatural character of the ruler, long ago repudiated by ourselves for example, has left behind it nothing more than the popular tendency to ascribe unusual goodness, wisdom, and beauty to the monarch. Loyalty, which originally meant implicit submission to the king's will, now means a merely nominal profession of subordination, and the fulfilment of certain forms of respect. By deposing some and putting others in their places, we have not only denied the divine rights of certain men to rule, but we have denied that they have any rights beyond those originating in the assent of the nation. Though our forms of speech and our State-documents still assert the subjection of the citizens to the ruler, our actual beliefs and our daily proceedings implicitly assert the contrary. We have entirely divested the monarch of legislative power, and should immediately rebel against his or her dictation even in matters of small concern.

Nor has the rejection of primitive political beliefs resulted only in transferring the power of a autocrat to a representative body. The views held respecting governments in general, of whatever form, are now widely different from those once held. Whether popular or despotic, governments in ancient times were supposed to have unlimited authority over their subjects. Individuals existed for the benefit of the State; not the State for the benefit of individuals. In our days, however, not only has the national will been in many cases substituted for the will of the king, but the exercise of this national will has been restricted. In England, for instance, though there has been established no definite doctrine respecting the bounds to governmental action, yet, in practice, sundry bounds to it are tacitly recognized by all. There is no organic law declaring that a legislature may not freely dispose of citizens' lives, as kings did of old, but were it possible for our legislature to attempt such a thing, its own destruction would be the consequence, rather than the destruction of citizens. How fully we have established the personal liberties of the subject against the invasions of State-power, would be quickly shown were it proposed by Act of Parliament to take possession of the nation, or of any class, and turn its services to public ends, as the services of the people were turned by Egyptian kings. Not only in our day have the claims of the citizen to life, liberty, and property been thus made good against the State, but sundry minor claims likewise. Ages ago laws regulating dress and mode of living fell into disuse, and any attempt to revive them would prove that such matters now lie beyond the sphere of legal control. For some centuries we asserted in practice, and have now established in theory, the right of every man to choose his own religious beliefs, instead of receiving State-authorized beliefs. Within the last few generations complete liberty of speech has been gained, in spite of all legislative attempts to suppress or limit it. And still more recently we have obtained under a few exceptional restrictions, freedom to trade with whomsoever we please. Thus our political beliefs are widely different from ancient ones, not only as to the proper depositary of power to be exercised over a nation, but also as to the extent of that power.

Nor even here has the change ended. Besides the average opinions just described as current among ourselves, there exists a less widely-diffused opinion going still further in the same direction. There are to be found men who contend that the sphere of government should be narrowed even more than it is in England. They hold that the freedom of the individual, limited only by the like freedom of other individuals, is sacred. They assert that the sole function of the State is the protection of persons against one another, and against a foreign foe; and they believe that the ultimate political condition must be one in which personal freedom is the greatest possible and governmental power the least possible.

Thus in different times and places we find, conceding the origin, authority, and functions of government, a great variety of opinions. What now must be said about the truth or falsity of these opinions? Must we say that some one is wholly right and all the rest wholly wrong; or must we say that each of them contains truth more or less disguised by errors? The latter alternative is the one which analysis will force upon us. Every one of these doctrines has for its vital element the recognition of an unquestionable fact. Directly or by implication, each insists on a certain subordination of individual actions to social dictates. There are differences respecting the power to which this subordination is due; there are differences respecting the motive for this subordination; there are differences respecting its extent; but that there must be some subordination all are agreed. The most submissive and the most recalcitrant alike hold that there are limits which individual actions may not transgress — limits which the one regards as originating in a ruler's will, and which the other regards as deducible from the equal claims of fellow-citizens.

It may doubtless be said that we here reach a very unimportant conclusion. The question, however, is not the value or novelty of the particular truth in this case arrived at. My aim has been to exhibit the more general truth, that between the most diverse beliefs there is usually something in common, — something taken for granted in each; and that this something, if not to be set down as an unquestionable verity, may yet be considered to have the highest degree of probability. A postulate which, like the one above instanced, is not consciously asserted but unconsciously involved, and which is unconsciously involved not by one man or body of men, but by numerous bodies of men who diverge in countless ways and degrees in the rest of their beliefs, has a warrant far transcending any that can be usually shown.

Do we not thus arrive at a generalization which may habitually guide us when seeking for the soul of truth in things erroneous? While the foregoing illustration brings home the fact that in opinions seeming to be absolutely wrong something right is yet to be found, it also indicates a way of finding the something right. This way is to compare all opinions of the same genus; to set aside as more or less discrediting one another those special and concrete elements in which such opinions disagree; to observe what remains after these have been eliminated; and to find for the remaining constituent that expression which holds true throughout its various disguises.

§3. A consistent adoption of the method indicated will greatly aid us in dealing with chronic antagonisms of belief. By applying it not only to ideas with which we are unconcerned, but also to our own ideas and those of our opponents, we shall be enabled to form more correct judgments. We shall be led to suspect that our convictions are not wholly right, and that the adverse convictions are not wholly wrong. On the one hand, we shall not, in common with the great mass of the unthinking, let our creed be determined by the mere accident of birth in a particular age on a particular part of the Earth's surface, while, on the other hand, we shall be saved from that error of entire and contemptuous negation, fallen into by most who take up an attitude of independent criticism.

Of all antagonisms of belief the oldest, the widest, the most profound, and the most important, is that between Religion and Science. It commenced when recognition of the commonest uniformities in surrounding things, set a limit to all-pervading superstitions. It shows itself everywhere throughout the domain of human knowledge; affecting men's interpretations alike of the simplest mechanical accidents and the most complex events in the histories of nations. It has its roots deep down in the diverse habits of thought of different orders of minds. And the conflicting conceptions of Nature and Life which these diverse habits of thought severally generate, influence for good or ill the tone of feeling and the daily conduct.

A battle of opinion like this which has been carried on for ages under the banners of Religion and Science, has generated an animosity fatal to a just estimate of either party by the other. Happily the times display an increasing catholicity of feeling, which we shall do well to carry as far as our natures permit. In proportion as we love truth more and victory less, we shall become anxious to know what it is which leads our opponents to think as they do. We shall begin to suspect that the pertinacity of belief exhibited by them must result from a perception of something we have not perceived. And we shall aim to supplement the portion of truth we have found with the portion found by them. Making a rational estimate of human authority, we shall avoid alike the extremes of undue submission and undue rebellion — shall not regard some men's judgments as wholly good and others as wholly bad; but shall, contrariwise, lean to the more defensible position that none are completely right and none are completely wrong. Preserving, as far as may be, this impartial attitude, let us then contemplate the two sides of this great controversy. Keeping guard against the bias of education and shutting out the whisperings of sectarian feeling, let us consider what are the a priori probabilities in favour of each party.

§4. The general principle above illustrated must lead us to anticipate that the diverse forms of religious belief which have existed and which still exist, have all a basis in some ultimate fact. Judging by analogy the implication is, not that any one of them is altogether right, but that in each there is something right more or less disguised by other things wrong. It may be that the soul of truth contained in erroneous creeds is extremely unlike most, if not all, of its several embodiments; and indeed if, as we have good reason to assume, it is much more abstract than any of them, its unlikeness necessarily follows. But some essential verity must be looked for. To suppose that these multiform conceptions should be one and all absolutely groundless, discredits too profoundly that average human intelligence from which all our individual intelligences are inherited.

To the presumption that a number of diverse beliefs of the same class have some common foundation in fact, must in this case be added a further presumption derived from the omnipresence of the beliefs. Religious ideas of one kind or other are almost universal. Grant that among all men who have passed a certain stage of intellectual development there are found vague notions concerning the origin and hidden nature of surrounding things, and there arises the inference that such notions are necessarily products of progressing intelligence. Their endless variety serves but to strengthen this conclusion: showing as it does a more or less independent genesis — showing how, in different places and times like conditions have led to similar trains of thought, ending in analogous results. A candid examination of the evidence quite negatives the supposition that creeds are priestly inventions. Even as a mere question of probabilities it cannot rationally be concluded that in every society, savage and civilized, certain men have combined to delude the rest in ways so analogous. Moreover, the hypothesis of artificial origin fails to account for the facts. It does not explain why under all changes of form, certain elements of religious belief remain constant. It does not show how it happens that while adverse criticism has from age to age gone on destroying particular theological dogmas, it has not destroyed the fundamental conception underlying those dogmas. Thus the universality of religious ideas, their independent evolution among different primitive races, and their great vitality unite in showing that their source must be deep-seated. In other words, we are obliged to admit that if not supernaturally derived as the majority contend, they must be derived out of human experiences, slowly accumulated and organized.

Should it be asserted that religious ideas are products of the religious sentiment which, to satisfy itself, prompts imaginations that it afterwards projects into the external world, and by-and-by mistakes for realities, the problem is not solved, but only removed farther back. Whence comes the sentiment? That it is a constituent in man's nature is implied by the hypothesis, and cannot indeed be denied by those who prefer other hypotheses. And if the religious sentiment, displayed constantly by the majority of mankind, and occasionally aroused even in those seemingly devoid of it, must be classed among human emotions, we cannot rationally ignore it. Here is an attribute which has played a conspicuous part throughout the entire past as far back as history records, and is at present the life of numerous institutions, the stimulus to perpetual controversies, and the prompter of countless daily actions. Evidently as a question in philosophy we are called on to say what this attribute means; and we cannot decline the task without confessing our philosophy to be incompetent.

Two suppositions only are open to us; the one that the feeling which responds to religious ideas resulted, along with all other human faculties, from an act of special creation; the other that it, in common with the rest, arose by a process of evolution. If we adopt the first of these alternatives, universally accepted by our ancestors and by the immense majority of our contemporaries, the matter is at once settled: man is directly endowed with the religious feeling by a creator; and to that creator it designedly responds. If we adopt the second alternative, then we are met by the questions — What are the circumstances to which the genesis of the religious feeling is due? and — What is its office? Considering, as we must on this supposition, all faculties to be results of accumulated modifications caused by the intercourse of the organism with its environment, we are obliged to admit that there exist in the environment certain phenomena or conditions which have determined the growth of the religious feeling, and so are obliged to admit that it is as normal as any other faculty. Add to which that as, on the hypothesis of a development of lower forms into higher the end towards which the progressive changes tend, must be adaptation to the requirements of life, we are also forced to infer that this feeling is in some way conducive to human welfare. Thus both alternatives contain the same ultimate implication. We must conclude that the religious sentiment is either directly created or is developed by the slow action of natural causes, and whichever conclusion we adopt requires us to treat the religious sentiment with respect.

One other consideration should not be overlooked — a consideration which students of Science more especially need to have pointed out. Occupied as such are with established truths, and accustomed to regard things not already known as things to be hereafter discovered, they are liable to forget that information, however extensive it may become, can never satisfy inquiry. Positive knowledge does not, and never can, fill the whole region of possible thought. At the uttermost reach of discovery there arises, and must ever arise, the question — What lies beyond? As it is impossible to think of a limit to space so as to exclude the idea of space lying outside that limit. so we cannot conceive of any explanation profound enough to exclude the question — What is the explanation of that explanation? Regarding Science as a gradually increasing sphere, we may say that every addition to its surface does not bring it into wider contact with surrounding nescience. There must ever remain therefore two antithetical modes of mental action. Throughout all future time, as now, the human mind may occupy itself, not only with ascertained phenomena and their relations, but also with that unascertained something which phenomena and their relations imply. Hence if knowledge cannot monopolize consciousness — if it must always continue possible for the mind to dwell upon that which transcends knowledge, then there can never cease to be a place for something of the nature of Religion; since Religion under all its forms is distinguished from everything else in this, that its subject matter passes the sphere of the intellect.

Thus, however untenable may be the existing religious creeds, however gross the absurdities associated with them, however irrational the arguments set forth in their defence, we must not ignore the verity which in all likelihood lies hidden within them. the general probability that widely-spread beliefs are not absolutely baseless, is in this case enforced by a further probability due to the omnipresence of the beliefs. In the existence of a religious sentiment, whatever be its origin, we have a second evidence of great significance. And as in that nescience which must ever remain the antithesis to science, there is a sphere for the exercise of this sentiment, we find a third general fact of like implication. We may be sure, therefore, that religions, even though no one of them be actually true, are yet all adumbrations of a truth.

§5. As, to the religious, it will seem absurd to set forth any justification for Religion, so, to the scientific, it will seem absurd to defend Science. Yet to do the last is certainly as needful as to do the first. If there exist some who, in contempt for its follies and disgust at its corruptions, have contracted towards Religion a repugnance which makes them overlook the fundamental truth contained in it; so, there are others offended to such a degree by the destructive criticisms men of science make on the religious tenets they hold essential, that they have acquired a strong prejudice against Science at large. they are not prepared with any reasons for their dislike. they have simply a remembrance of the rude shakes which Science has given to many of their cherished convictions, and a suspicion that it may eventually uproot all they regard as sacred; and hence it produces in them an inarticulate dread.

What is Science? To see the absurdity of the prejudice against it, we need only remark that Science is simply a higher development of common knowledge; and that if Science is repudiated, all knowledge must be repudiated along with it. The extremest bigot will not suspect any harm in the observation that the Sun rises earlier and sets later in summer than in winter. but will rather consider such an observation as a useful aid in fulfilling the duties of life. Well, Astronomy is an organized body of kindred observations, made with greater nicety, extended to a larger number of objects, and so analyzed as to disclose the real arrangements of the heavens and to dispel our false conceptions of them. That iron will rust in water, that wood will burn, that long kept viands become putrid, the most timid sectarian will teach without alarm, as things useful to be known. But these are chemical truths: Chemistry is a systematized collection of such facts, ascertained with precision, and so classified and generalized as to enable us to say with certainty, concerning each simple or compound substance, what change will occur in it under given conditions. And thus is it with all the sciences. They severally germinate out of the experiences of daily life. insensibly as they grow they draw in remoter, more numerous, and more complex experiences; and among these, they ascertain laws of dependence like those which make up our knowledge of the most familiar objects. Nowhere is it possible to draw a line and say — here Science begins. And as it is the function of common observation to serve for the guidance of conduct; so, too, is the guidance of conduct the office of the most recondite and abstract results of Science. Through the countless industrial processes and the various modes of locomotion it has given to us, Physics regulates more completely our social life than does his acquaintance with the properties of surrounding bodies regulate the life of the savage. All Science is prevision; and all prevision ultimately helps us in greater or less degree to achieve the good and avoid the bad. Thus being one in origin and function, the simplest forms of cognition and the most complex must be dealt with alike. We are bound in consistency to receive the widest knowledge our faculties can reach, or to reject along with it that narrow knowledge possessed by all.

To ask the question which more immediately concerns our argument — whether Science is substantially true? — is much like asking whether the Sun gives light. And it is because they are conscious how undeniably valid are most of its propositions, that the theological party regard Science with so much secret alarm. They know that during the five thousand years of its growth, some of its larger divisions — mathematics, physics, astronomy — have been subject to the rigorous criticism of successive generations, and have notwithstanding become ever more firmly established. They know that, unlike many of their own doctrines, which were once universally received but have age by age been more widely doubted, the doctrines of Science, at first confined to a few scattered inquirers, have been slowly growing into general acceptance, and are now in great part admitted as beyond dispute. They know that scientific men throughout the world subject one another's results to searching examination; and that error is mercilessly exposed and rejected as soon as discovered. And, finally they know that still more conclusive evidence is furnished by the daily verification of scientific predictions, and by the never-ceasing triumphs of those arts which Science guides.

To regard with alienation that which has such high credentials is a folly. Though in the tone which many of the scientific adopt towards them, the defenders of Religion may find some excuse for this alienation, yet the excuse is an insufficient one. On the side of Science, as on their own side, they must admit that short-comings in the advocates do not tell essentially against that which is advocated. Science must be judged by itself; and so judged, only the most perverted intellect can fail to see that it is worthy of all reverence. Be there or be there not any other revelation, we have a veritable revelation in Science — a continuous disclosure of the established order of the Universe. This disclosure it is the duty of every one to verify as far as in him lies; and having verified, to receive with all humility.

§6. Thus there must be right on both sides of this great controversy. Religion, everywhere present as a warp running through the weft of human history, expresses some eternal fact; while Science is an organized body of truths, ever growing, and ever being purified from errors. And if both have bases in the reality of things, then between them there must be a fundamental harmony. It is impossible that there should be two orders of truth in absolute and everlasting opposition. Only in pursuance of some Manichean hypothesis, which among ourselves no one dares openly avow, is such a supposition even conceivable. That Religion is divine and Science diabolical, is a proposition which, though implied in many a clerical declamation, not the most vehement fanatic can bring himself distinctly to assert. And whoever does not assert this, must admit that under their seeming antagonism lies hidden an entire agreement.

Each side, therefore, has to recognize the claims of the other as representing truths which are not to be ignored. It behoves each to strive to understand the other, with the conviction that the other has something worthy to be understood; and with the conviction that when mutually recognized this something will be the basis of a reconciliation.

How to find this something thus becomes the problem we should perseveringly try to solve. Not to reconcile them in any makeshift way, but to establish a real and permanent peace. The thing we have to seek out is that ultimate truth which both will avow with absolute sincerity — with not the remotest mental reservation. There shall be no concession — no yielding on either side of something that will by-and-by be reasserted; but the common ground on which they meet shall be one which each will maintain for itself. We have to discover some fundamental verity which Religion will assert, with all possible emphasis, in the absence of Science; and which Science, with all possible emphasis, will assert in the absence of Religion. We must look for a conception which combines the conclusions of both — must see how Science and Religion express opposite sides of the same fact: the one its near or visible side, and the other its remote or invisible side.

Already in the foregoing pages the method of seeking such a reconciliation has been vaguely shadowed forth. Before proceeding, however, it will be well to treat the question of method more definitely. To find that truth in which Religion and Science coalesce, we must know in what direction to look for it, and what kind of truth it is likely to be.

§7. Only in some highly abstract proposition can Religion and Science find a common ground. Neither such dogmas as those of the trinitarian and unitarian, nor any such idea as that of propitiation, common though it may be to all religions, can serve as the desired basis of agreement; for Science cannot recognize beliefs like these: they lie beyond its sphere. Not only, as we have inferred, is the essential truth contained in Religion that most abstract element pervading all its forms, but, as we here see, this most abstract element is the only one in which Religion is likely to agree with Science.

Similarly if we begin at the other end, and inquire what scientific truth can unite Science with Religion. Religion can take no cognizance of special scientific doctrines; any more than Science can take cognizance of special religious doctrines. The truth which Science asserts and Religion indorses cannot be one furnished by mathematics; nor can it be a physical truth; nor can it be a truth in chemistry. No generalization of the phenomena of space, of time, of matter, or of force, can become a Religious conception. Such a conception, if it anywhere exists in Science, must be more general than any of these — must be one underlying all of them.

Assuming, then, that since these two great realities are constituents of the same mind, and respond to different aspects of the same Universe, there must be a fundamental harmony between them, we see good reason to conclude that the most abstract truth contained in Religion and the most abstract truth contained in Science must be the one in which the two coalesce. The largest fact to be found within our mental range must be the one of which we are in search. Uniting these positive and negative poles of human thought, it must be the ultimate fact in our intelligence.

§8. Before proceeding let me bespeak a little patience. The next three chapters, setting out from different points and converging to the same conclusion, will be unattractive. Students of philosophy will find in them much that is familiar and to most of those who are unacquainted with modern metaphysics, their reasonings may prove difficult to follow.

Our argument, however, cannot dispense with these chapters, and the greatness of the question at issue justifies even a heavier tax on the reader's attention. Though it affects us little in a direct way, the view we arrive at must indirectly affect us all in our relations — must determine Our conceptions of the Universe, of Life, of Human Nature — must influence our ideas of right and wrong, and therefore modify our conduct. To reach that point of view from which the seeming discordance of Religion and Science disappears, and the two merge into one, must surely be worth an effort.

Here ending preliminaries let us now address ourselves to this all-important inquiry.

Chapter 2

Ultimate Religious Ideas

§9. When, on the sea-shore, we note how the hulls of distant vessels are hidden below the horizon, and how, of still remoter vessels, only the uppermost sails are visible, we may conceive with tolerable clearness the slight curvature of that portion of the sea's surface which lies before us. But when we try to follow out in imagination this curved surface as it actually exists, slowly bending round until all its meridians meet in a point eight thousand miles below our feet, we find ourselves utterly baffled. We cannot conceive in its real form and magnitude even that small segment of our globe which extends a hundred miles on every side of us, much less the globe as a whole. The piece of rock on which we stand can be mentally represented with something like completeness: we are able to think of its top, its sides, and its under surface at the same time, or so nearly at the same time that they seem present in consciousness together; and so we can form what we call a conception of the rock. But to do the like with the Earth is impossible. If even to imagine the antipodes as at that distant place in space which it actually occupies, is beyond our power much more beyond our power must it be at the same time to imagine all other remote points on the Earth's surface as in their actual places. Yet we commonly speak as though we had an idea of the Earth — as though we could think of it in the same way that we think of minor objects.

What conception, then, do we form of it? the reader may ask. That its name calls up in us some state of consciousness is unquestionable; and if this state of consciousness is not a conception, properly so called, what is it? The answer seems to be this: — We have learnt by indirect methods that the Earth is a sphere; we have formed models approximately representing its shape and the distribution of its parts; usually when the Earth is referred to, we either think of an indefinitely extended mass beneath our feet, or else, leaving out the actual Earth, we think of a body like a terrestrial globe; but when we seek to imagine the Earth as it really is, we join these two ideas as well as we can — such perception as our eyes give us of the Earth's surface we couple with the conception of a sphere. And thus we form of the Earth not a conception properly so called, but only a symbolic conception.*

<* Those who may have before met with this term, will perceive that it is here used in quite a different sense.>

A large proportion of our conceptions, including all those of much generality, are of this order. Great magnitudes, great durations, great numbers, are none of them actually conceived, but are all of them conceived more or less symbolically; and so, too, are all those classes of objects of which we predicate some common fact. When mention is made of any individual man, a tolerably complete idea of him is formed. If the family he belongs to be spoken of, probably but a part of it will be represented in thought: under the necessity of attending to that which is said about the family, we realize in imagination only its most important or familiar members, and pass over the rest with a nascent consciousness which we know could, if requisite, be made complete. Should something be remarked of the class, say farmers, to which this family belongs, we neither enumerate in thought all the individuals contained in the class, nor believe that we could do so if required; but we are content with taking some few samples of it, and remembering that these could be indefinitely multiplied. Supposing the subject of which something is predicated be Englishmen, the answering state of consciousness is a still more inadequate representative. Yet more remote is the likeness of the thought to the thing, if reference be made to Europeans or to human beings. And when we come to propositions concerning the mammalia, or conceding the whole of the vertebrata, or concerning all organic beings, the unlikenesses of our conceptions to the realities become extreme.

Throughout which series of instances we see that as the number of objects grouped together in thought increases, the concept, formed of a few typical samples joined with the notion of multiplicity, becomes more and more a mere symbol; not only because it gradually ceases to represent the size of the group, but also because, as the group grows more heterogeneous, the typical samples thought of are less like the average objects which the group contains.

This formation of symbolic conceptions, which inevitably arises as we pass from small and concrete objects to large and to discrete ones, is mostly a useful, and indeed necessary, process. When, instead of things whose attributes can be tolerably well united in a single state of consciousness, we have to deal with things whose attributes are too vast or numerous to be so united, we must either drop in thought part of their attributes, or else not think of them at all — either form a more or less symbolic conception, or no conception. We must predicate nothing of objects too great or too multitudinous to be mentally represented, or we must make our predications by the help of extremely inadequate representations of them.

But while by doing this we are enabled to form general propositions, and so to reach general conclusions, we are perpetually led into danger, and very often into error. We mistake our symbolic conceptions for real ones; and so are betrayed into countless false inferences. Not only is it that in proportion as the concept we form of any thing, or class of things, misrepresents the reality, we are apt to be wrong in any assertion we make respecting the reality; but it is that we are led to suppose we have truly conceived many things which we have conceived only in this fictitious way; and then to confound with these some things which cannot be conceived in any way. How we fall into this error almost unavoidably it will be needful here to observe.

From objects fully representable, to those of which we cannot form even approximate representations, there is an insensible transition. Between a pebble and the entire Earth a series of magnitudes might be introduced, severally differing from adjacent ones so slightly that it would be impossible to say at what point in the series our conceptions of them became inadequate. Similarly, there is a gradual progression from those groups of a few individuals which we can think of as groups with tolerable completeness, to those larger and larger groups of which we can form nothing like true ideas. Thus we pass from actual conceptions to symbolic ones by infinitesimal steps. Note next that we are led to deal with our symbolic conceptions as though they were actual ones, not only because we cannot clearly separate the two, but also because, in most cases, the first serve our purposes nearly or quite as well as the last — are simply the abbreviated signs we substitute for those more elaborate signs which are our equivalents for real objects. Those imperfect representations of ordinary things which we make in thinking, we know can be developed into adequate ones if needful. Those concepts of larger magnitudes and more extensive classes which we cannot make adequate, we still find can be verified by some indirect process of measurement or enumeration. And even in the case of such an utterly inconceivable object as the Solar System, we yet, through the fulfilment of predictions founded on our symbolic conception of it, gain the conviction that this stands for an actual existence, and, in a sense, truly expresses certain of its constituent relations. So that having learnt by long experience that our symbolic conceptions can, if needful, be verified, we are led to accept them without verification. Thus we open the door to some which profess to stand for known things, but which really stand for things that cannot be known in any way.

The implication is clear. When our symbolic conceptions are such that no cumulative or indirect processes of thought can enable us to ascertain that there are corresponding actualities, nor any fulfilled predictions be assigned in justification of them, then they are altogether vicious and illusive, and in no way distinguishable from pure fictions.

§10. And now to consider the bearings of this general truth on our immediate topic — Ultimate Religious Ideas.

To the primitive man sometimes happen things which are out of the ordinary course-diseases, storms, earth-quakes, echoes, eclipses. From dreams arises the idea of a wandering double; whence follows the belief that the double, departing permanently at death, is then a ghost. Ghosts thus become assignable causes for strange occurrences. The greater ghosts are presently supposed to have extended spheres of action. As men grow intelligent the conceptions of these minor invisible agencies merge into the conception of a universal invisible agency; and there result hypotheses concerning the origin, not of special incidents only, but of things in general.

A critical examination, however will prove not only that no current hypothesis is tenable, but also that no tenable hypothesis can be framed.

§11. Respecting the origin of the Universe three verbally intelligible suppositions may be made. We may assert that it is self-existent; or that it is self-created; or that it is created by an external agency. Which of these suppositions is most credible it is not needful here to inquire. The deeper question, into which this finally merges, is, whether any one of them is even conceivable in the true sense of the word. Let us successively test them.

When we speak of a man as self-supporting, of an apparatus as self-acting, or of a tree as self-developed, our expressions, however inexact, stand for things that can be figured in thought with tolerable completeness. Our conception of the self-development of a tree is doubtless symbolic. But though we cannot really represent in consciousness the. entire series of complex changes through which the tree passes, yet we can thus represent the leading traits of the series; and general experience teaches us that by long continued observation we could gain the power of more fully representing it. That is, we know that our symbolic conception of self-development can be expanded into something like a real conception; and that it expresses, however rudely, an actual process. But when we speak of self-existence and, helped by the above analogies, form some vague symbolic conception of it, we delude ourselves in supposing that this symbolic conception is of the same order as the others. On joining the word self to the word existence, the force of association makes us believe we have a thought like that suggested by the compound word self-acting. An endeavour to expand this symbolic conception, however, will undeceive us. In the first place, it is clear that by self-existence we especially mean an existence independent of any other — not produced by any other: the assertion of self-existence is an indirect denial of creation. In thus excluding the idea of any antecedent cause, we necessarily exclude the idea of a beginning. for to admit that there was a time when the existence had not commenced, is to admit that its commencement was determined by something, or was caused, which is a contradiction. Self-existence, therefore, necessarily means existence without a beginning; and to form a conception of self-existence is to form a conception of existence without a beginning. Now by no mental effort can we do this. To conceive existence through infinite past-time, implies the conception of infinite past-time, which is an impossibility. To this let us add that even were self-existence conceivable, it would not be an explanation of the Universe. No one will say that the existence of an object at the present moment is made easier to understand by the discovery that it existed an hour ago, or a day ago, or a year ago; and if its existence now is not made more comprehensible by knowledge of its existence during some previous finite period, then no knowledge of it during many such finite periods, even could we extend them to an infinite period, would make it more comprehensible. Thus the Atheistic theory is not only absolutely unthinkable, but, even were it thinkable, would not be a solution. The assertion that the Universe is self-existent does not really carry us a step beyond the cognition of its present existence; and so leaves us with a mere re-statement of the mystery.

The hypothesis of self-creation, which practically amounts to what is called Pantheism, is similarly incapable of being represented in thought. Certain phenomena, such as the precipitation of invisible vapour into cloud, aid us in forming a symbolic conception of a self-evolved Universe; and there are not wanting indications in the Heavens, and on the Earth, which help us in giving to this conception some distinctness. But while the succession of phases through which the visible Universe has passed in reaching its present form, may perhaps be comprehended as in a sense self-determined; yet the impossibility of expanding our symbolic conception of self-creation into a real conception, remains as complete as ever. Really to conceive self-creation, is to conceive potential existence passing into actual existence by some inherent necessity, which we cannot. We cannot form any idea of a potential existence of the Universe, as distinguished from its actual existence. If represented in thought at all, potential existence must be represented as something, that is, as an actual existence: to suppose that it can be represented as nothing involves two absurdities — that nothing is more than a negation, and can be positively represented in thought, and that one nothing is distinguished from all other nothings by its power to develop into something. Nor is this all. We have no state of consciousness answering to the words an inherent necessity by which potential existence became actual existence. To render them into thought, existence, having for an indefinite period remained in one form, must be conceived as passing without any external impulse into another form; and this involves the idea of a change without a cause — a thing of which no idea is possible. Thus the terms of this hypothesis do not stand for real thoughts, but merely suggest the vaguest symbols not admitting of any interpretation. Moreover, even were potential existence conceivable as a different thing from actual existence, and could the transition from the one to the other be mentally realized as self-determined, we should still be no forwarder: the problem would simply be removed a step back. For whence the potential existence? This would just as much require accounting for as actual existence, and just the same difficulties would meet us. The self-existence of a potential Universe is no more conceivable than the self-existence of the actual Universe. The self-creation of a potential Universe would involve over again the difficulties just stated — would imply behind this potential universe a more remote potentiality, and so on in an infinite series, leaving us at last no forwarder than at first. While to assign an externa1 agency as its origin, would be to introduce the notion of a potential Universe for no purpose whatever.

There remains the commonly — received or theistic hypothesis — creation by external agency. Alike in the rudest creeds and in the cosmogony long current among ourselves, it is assumed that the Heavens and the Earth were made somewhat after the manner in which a workman makes a piece of furniture. And this is the assumption not only of theologians but of most philosophers. Equally in the writings of Plato and in those of not a few living men of science, we find it assumed that there is an analogy between the process of creation and the process of manufacture. Now not only is this conception one which cannot by any cumulative process of thought, or the fulfilment of predictions based on it, be shown to answer to anything actual; but it cannot be mentally realized, even when all its assumptions are granted. Though the proceedings of a human artificer may vaguely symbolize a method after which the Universe might be shaped, yet imagination of this method does not help us to solve the ultimate problem; namely, the origin of the materials of which the Universe consists. The artizan does not make the iron, wood, or stone, he uses, but merely fashions and combines them. If we suppose suns, and planets, and satellites, and all they contain to have been similarly formed by a "Great Artificer," we suppose merely that certain pre-existing elements were thus put into their present arrangement. But whence the pre-existing elements? The production of matter out of nothing is the real mystery which neither this simile nor any other enables us to conceive; and a simile which does not enable us to conceive this may as well be dispensed with. Still more manifest becomes the insufficiency of this theory of things, when we turn from material objects to that which contains them — when instead of matter we contemplate space. Did there exist nothing but an immeasurable void, explanation would be needed as much as it is now. There would still arise the question — how came it so? If the theory of creation by external agency were an adequate one, it would supply an answer; and its answer would be — space was made in the same manner that matter was made. But the impossibility of conceiving this is so manifest that no one dares to assert it. For if space was created it must have been previously non-existent. The non-existence of space cannot, however, by any mental effort be imagined. And if the non-existence of space is absolutely inconceivable, then, necessarily, its creation is absolutely inconceivable. Lastly, even supposing that the genesis of the Universe could really be represented in thought as due to an external agency, the mystery would be as great as ever; for there would still arise the question — how came there to be an external agency? To account for this only the same three hypotheses are possible — self-existence, self-creation, and creation by external agency. Of these the last is useless: it commits us to an infinite series of such agencies, and even then leaves us where we were. By the second we are led into the same predicament; since, as already shown, self-creation implies an infinite series of potential existences. We are obliged, therefore, to fall back on the first, which is the one commonly accepted and commonly supposed to be satisfactory. Those who cannot conceive a self-existent Universe, and therefore assume a creator as the source of the Universe, take for granted that they can conceive a self-existent Creator. The mystery which they recognize in this great fact surrounding them on every side, they transfer to an alleged source of this great fact, and then suppose that they have solved the mystery. But they delude themselves. As was proved at the outset of the argument, self-existence is inconceivable; and this holds true whatever be the nature of the object of which it is predicated. Whoever agrees that the atheistic hypothesis is untenable because it involves the impossible idea of self-existence, must perforce admit that the theistic hypothesis is untenable if it contains the same impossible idea.

Thus these three different suppositions, verbally intelligible though they are, and severally seeming to their respective adherents quite rational, turn out, when critically examined, to be literally unthinkable. It is not a question of probability, or credibility, but of conceivability. Experiment proves that the elements of these hypotheses cannot even be put together in consciousness; and we can entertain them only as we entertain such pseud-ideas as a square fluid and a moral substance — only by abstaining from the endeavour to render them into actual thoughts. Or, reverting to our original mode of statement, we may say that they severally involve symbolic conceptions of the illegitimate and illusive kind. Differing so widely as they seem to do, the atheistic, the pantheistic, and the theistic hypotheses contain the same ultimate element. It is impossible to avoid making the assumption of self-existence somewhere; and whether that assumption be made nakedly or under complicated disguises, it is equally vicious, equally unthinkable. Be it a fragment of matter, or some fancied potential form of matter, or some more remote and still less imaginable mode of being, our conception of its self-existence can be framed only by joining with it the notion of unlimited duration through past time. And as unlimited duration is inconceivable, all those formal ideas into which it enters are inconceivable; and indeed, if such an expression is allowable, are the more inconceivable in proportion as the other elements of the ideas are indefinite. So that in fact, impossible as it is to think of the actual Universe as self-existing, we do but multiply impossibilities of thought by every attempt we make to explain its existence.

§12. If from the origin of the Universe we turn to its nature, the like insurmountable difficulties rise up before us on all sides — or rather, the same difficulties under new aspects. We find ourselves obliged to make certain assumptions; and yet we find these assumptions cannot be represented in thought.

When we inquire what is the meaning of the effects produced on our senses — when we ask how there come to be in our consciousness impressions of sounds, of colours, of tastes, and of those various attributes we ascribe to bodies, we are compelled to regard them as the effects of some cause. We may stop short in the belief that this cause is what we call matter. Or we may conclude, as some do, that matter is only a certain mode of manifestation of spirit, which is therefore the true cause. Or, regarding matter and spirit as proximate agencies, we may ascribe the changes wrought in our consciousness to immediate divine power. But be the cause we assign what it may, we are obliged to suppose some cause. And we are obliged not only to suppose some cause, but also a first cause. The matter, or spirit or other agent producing these impressions on us, must either be the first cause of them or not. If it is the first cause the conclusion is reached. If it is not the first cause, then by implication there must be a cause behind it, which thus becomes the real cause of the effect. Manifestly however complicated the assumptions, the same conclusion must be reached. We cannot ask how the changes in our consciousness are caused, without inevitably committing ourselves to the hypothesis of a First Cause.

But now if we ask what is the nature of this First Cause, we are driven by an inexorable logic to certain further conclusions. Is the First Cause finite or infinite? If we say finite we involve ourselves in a dilemma. To think of the First Cause as finite, is to think of it as limited. To think of it as limited implies a consciousness of something beyond its limits: it is impossible to conceive a thing as bounded without assuming a region surrounding its boundaries. What now must we say of this region? If the First Cause is limited, and there consequently lies something outside of it, this something must have no First Cause — must be uncaused. But if we admit that there can be something uncaused, there is no reason to assume a cause for anything. If beyond that finite region over which the First Cause extends, there lies a region, which we are compelled to regard as infinite, over which it does not extend — if we admit that there is an infinite uncaused surrounding the finite caused; we tacitly abandon the hypothesis of causation altogether. Thus it is impossible to consider the First Cause as finite. But if it cannot be finite it must be infinite.

Another inference conceding the First Cause is equally necessary. It must be independent. If it is dependent it cannot be the First Cause; for that must be the First Cause on which it depends. It is not enough to say that it is partially independent; since this implies some necessity which determines its partial dependence, and this necessity, be it what it may, must be a higher cause, or the true First Cause, which is a contradiction. But to think of the First Cause as totally independent, is to think of it as that which exists in the absence of all other existence; seeing that if the presence of any other existence is necessary, it must be partially dependent on that other existence, and so cannot be the First Cause. Not only however must the First Cause be a form of being which has no necessary relation to any other form of being, but it can have no necessary relation within itself. There can be nothing in it which determines change, and yet nothing which prevents change. For if it contains something which imposes such necessities or restraints, this something must be a cause higher than the First Cause, which is absurd. Thus the First Cause must be in every sense perfect, complete, total: including within itself all power and transcending all law. Or to use the established word, it must be Absolute.

Certain conclusions respecting the nature of the Universe, thus seem unavoidable. In our search after causes, we discover no resting place until we arrive at a First Cause; and we have no alternative but to regard this First Cause as Infinite and Absolute. These are inferences forced on us by arguments from which there appears no escape. Nevertheless neither arguments nor inferences have more than nominal values. It might easily be shown that the materials of which the arguments are built, equally with the conclusions based on them, are merely symbolic conceptions of the illegitimate order. Instead, however, of repeating the disproof used above, it will be well to pursue another method; showing the fallacy of these conclusions by disclosing their mutual contradictions.

Here I cannot do better than avail myself of the demonstration which Mr. Mansel, carrying out in detail the doctrine of Sir William Hamilton, has given in his Limits of Religious Thought. And I gladly do this, not only because his mode of presentation cannot be improved, but also because, writing as he does in defence of the current Theology, his reasonings will be the more acceptable to the majority of readers.

§13. Having given preliminary definitions of the First Cause, of the Infinite, and of the Absolute, Mr. Mansel says: —

"But these three conceptions, the Cause, the Absolute, the Infinite, all equally indispensable, do they not imply contradiction to each other, when viewed in conjunction, as attributes of one and the same Being? A Cause cannot, as such, be absolute: the Absolute cannot, as such, be a cause. The cause, as such, exists only in relation to its effect: the cause is a cause of the effect; the effect is an effect of the cause. On the other hand, the conception of the Absolute implies a possible existence out of all relation. We attempt to escape from this apparent contradiction, by introducing the idea of succession in time. The Absolute exists first by itself, and afterwards becomes a Cause. But here we are checked by the third conception, that of the Infinite. How can the Infinite become that which it was not from the first? If Causation is a possible mode of existence, that which exists without causing is not infinite; that which becomes a cause has passed beyond its former limits. * * *

"Supposing the Absolute to become a cause, it will follow that it operates by means of freewill and consciousness. For a necessary cause cannot be conceived as absolute and infinite. If necessitated by something beyond itself, it is thereby limited by a superior power; and if necessitated by itself, it has in its own nature a necessary relation to its effect. The act of causation must therefore be voluntary; and volition is only possible in a conscious being. But consciousness again is only conceivable as a relation. There must be a conscious subject, and an object of which he is conscious. The subject is a subject to the object; the object is an object to the subject; and neither can exist by itself as the absolute. This difficulty, again, may be for the moment evaded, by distinguishing between the absolute as related to another and the absolute as related to itself. The Absolute, it may be said, may possibly be conscious, provided it is only conscious of itself. But this alternative is, in ultimate analysis, no less self-destructive than the other. For the object of consciousness, whether a mode of the Subject's existence or not, is either created in and by the act of consciousness, or has an existence independent of it. In the former case, the object depends upon the subject, and the subject alone is the true absolute. In the latter case, the subject depends upon the object, and the object alone is the true absolute. Or if we attempt a third hypothesis, and maintain that each exists independently of the other, we have no absolute at all, but only a pair of relatives; for coexistence, whether in consciousness or not, is itself a relation.

"The corollary from this reasoning is obvious. Not only is the Absolute, as conceived, incapable of a necessary relation to anything else but it is also incapable of containing, by the constitution of its own nature, an essential relation within itself; as a whole, for instance, composed of parts, or as a substance consisting of attributes, or as a conscious subject in antithesis to an object. For if there is in the absolute any principle of unity, distinct from the mere accumulation of parts or attributes, this principle alone is the true absolute. If, on the other hand, there is no such principle, then there is no absolute at all, but only a plurality of relatives. The almost unanimous voice of philosophy, in pronouncing that the absolute is both one and simple, must be accepted as the voice of reason also, so far as reason has any voice in the matter. But this absolute unity, as indifferent and containing no attributes, can neither be distinguished from the multiplicity of finite beings by any characteristic feature, nor be identified with them in their multiplicity. Thus we are landed in an inextricable dilemma. The Absolute cannot be conceived as conscious, neither can it be conceived as unconscious; it cannot be conceived as complex, neither can it be conceived as simple: it cannot be conceived by difference, neither can it be conceived by the absence of difference: it cannot be identified with the universe, neither can it be distinguished from it. The One and the Many, regarded as the beginning of existence, are thus alike incomprehensible.

"The fundamental conceptions of Rational Theology being thus self-destructive, we may naturally expect to find the same antagonism manifested in their special applications. * * * How, for example. Can Infinite Power be able to do all things, and yet Infinite Goodness be unable to do evil? How can Infinite Justice exact the utmost penalty for every sin, and yet Infinite Mercy pardon the sinner? How can Infinite Wisdom know all that is to come, and yet Infinite Freedom be at liberty to do or to forbear? How is the existence of Evil compatible with that of an infinitely perfect Being; for if he wills it, he is not infinitely good; and if he will it not, his will is thwarted and his sphere of action limited? * * *

"Let us, however, suppose for an instant that these difficulties are surmounted, and the existence of the Absolute securely established on the testimony of reason. Still we have not succeeded in reconciling this idea with that of a Cause: we have done nothing towards explaining how the absolute can give rise to the relative, the infinite to the finite. If the condition of causal activity is a higher state than that of quiescence, the Absolute, whether acting voluntarily or involuntarily, has passed from a condition of comparative imperfection to one of comparative perfection; and therefore was not originally perfect. If the state of activity is an inferior state to that of quiescence, the Absolute, in becoming a cause, has lost its original perfection. There remains only the supposition that the two states are equal, and the act of creation one of complete indifference. But this supposition annihilates the unity of the absolute, or it annihilates itself. If the act of creation is real, and yet indifferent, we must admit the possibility of two conceptions of the absolute, the one as productive, the other as non-productive. If the act is not real, the supposition itself vanishes. * * *

"Again, how can the relative be conceived as coming into being? If it is a distinct reality from the absolute, it must be conceived as passing from non-existence into existence. But to conceive an object as non-existent, is again a self-contradiction; for that which is conceived exists, as an object of thought, in and by that conception. We may abstain from thinking of an object at all; but, if we think of it, we cannot but think of it as existing. It is possible at one time not to think of an object at all, and at another to think of it as already in being; but to think of it in the act of becoming, in the progress from not being into being, is to think that which, in the very thought, annihilates itself. * * *

"To sum up briefly this portion of my argument. The conception of the Absolute and Infinite, from whatever side we view it, appears encompassed with contradictions. There is a contradiction in supposing such an object to exist, whether alone or in conjunction with others; and there is a contradiction in supposing it not to exist. There is a contradiction in conceiving it as one; and there is a contradiction in conceiving it as many. There is a contradiction in conceiving it as personal; and there is a contradiction in conceiving it as impersonal. It cannot, without contradiction, be represented as active; nor, without equal contradiction, be represented as inactive. It cannot be conceived as the sum of all existence; nor yet can it be conceived as a part only of that sum."

§14. And now what is the bearing of these results on the question before us? Our examination of Ultimate Religious Ideas has been carried on with the view of making manifest some fundamental verity contained in them. Thus far, however, we have arrived at negative conclusions only. Passing over the consideration of credibility, and confining ourselves to that of conceivability we have seen that Atheism, Pantheism, and Theism, when rigorously analyzed, severally prove to be wholly unthinkable. Instead of disclosing a fundamental verity existing in each, our inquiry seems rather to have shown that there is no fundamental verity contained in any. To carry away this conclusion, however, would be a fatal error, as we shall shortly see.

Leaving out the accompanying code of conduct, which is a supplementary growth, a religious creed is definable as a theory of original causation. By the lowest savages the genesis of things is not inquired about: only strange appearances and actions raise the question of agency. But be it in the primitive Ghost-theory, which assumes a human personality behind each unusual phenomenon; be it in Polytheism, in which such personalities are partially generalized; be it in Monotheism, in which they are wholly generalized; or be it in Pantheism, in which the generalized personality becomes one with the phenomena; we equally find an hypothesis which is supposed to render the Universe comprehensible. Nay, even that which is regarded as the negation of all Religion — even positive Atheism — comes within the definition; for it, too, in asserting the self-existence of Space, Matter and Motion, propounds a theory from which it holds the facts to be deducible. Now every theory tacitly asserts two things: first, that there is something to be explained; second, that such and such is the explanation. Hence, however widely different speculators disagree in the solutions they give of the same problem, yet by implication they agree that there is a problem to be solved. Here then is an element which all creeds have in common. Religions diametrically opposed in their overt dogmas, are perfectly at one in the tacit conviction that the existence of the world with all it contains and all which surrounds it, is a mystery calling for interpretation.

Thus we come within sight of that which we seek. In the last chapter, reasons were given for inferring that human beliefs in general, and especially the perennial ones, contain, under whatever disguises of error, some soul of truth; and here we have arrived at a truth underlying even the rudest beliefs. We saw, further, that this soul of truth is most likely some constituent common to conflicting opinions of the same order; and here we have a constituent contained by all religions. It was pointed out that this soul of truth would almost certainly be more abstract than any of the creeds involving it; and the truth above reached is one exceeding in abstractness the most abstract religious doctrines. In every respect, therefore, our conclusion answers to the requirements.

That this is the vital element in all religions is further shown by the fact that it is the element which not only survives every change but grows more distinct the more highly the religion is developed. Aboriginal creeds, pervaded by thoughts of personal agencies which are usually unseen, conceive these agencies under perfectly concrete and ordinary forms-class them with the visible agencies of men and animals; and so hide a vague perception of mystery in disguises as unmysterious as possible. Polytheistic conceptions in their advanced phases, represent the presiding personalities in idealized shapes, working in subtle ways, and communicating with men by omens or through inspired persons; that is, the ultimate causes of things are regarded as less familiar and comprehensible. The growth of a Monotheistic faith, accompanied as it is by lapse of those beliefs in which the divine nature is assimilated to the human in all its lower propensities, shows us a further step in the same direction; and however imperfectly this higher faith is at first held, we yet see in altars "to the unknown and unknowable God," and in the worship of a God who cannot by any searching be found out, that there is a clearer recognition of the inscrutableness of creation. Further developments of theology, ending in such assertions as that "a God understood would be no God at all," and "to think that God is, as we can think him to be, is blasphemy," exhibit this recognition still more distinctly. It pervades all the cultivated theology of the present day. So that while other elements of religious creeds one by one drop away, this remains and grows ever more manifest, and thus is shown to be the essential element.

Here, then, is a truth in which religions in general agree with one another, and with a philosophy antagonistic to their special dogmas. If Religion and Science are to be reconciled, the basis of reconciliation must be this deepest, widest, and most certain of all facts-that the Power which the Universe manifests to us is inscrutable.

Chapter 3

Ultimate Scientific Ideas

§15. What are Space and Time? Two hypotheses are current respecting them: the one that they are objective, the other that they are subjective. Let us see what becomes of these hypotheses under analysis.

To say that Space and Time exist objectively, is to say that they are entities. The assertion that they are non-entities is self-destructive: non-entities are non-existences; and to allege that non-existences exist objectively is a contradiction in terms. Moreover, to deny that Space and Time are things, and so by implication to call them nothings, involves the absurdity that there are two kinds of nothing. Neither can they be regarded as attributes of some entity. Not only is it impossible to conceive any entity of which they are attributes, but we cannot think of them as disappearing, even if everything else disappeared; whereas attributes necessarily disappear along with the entities they belong to. Thus as Space and Time can be neither non-entities nor the attributes of entities, we are compelled to consider them as entities. But while, on the hypothesis of their objectivity, Space and Time must be classed as things, we find that to represent them in thought as things is impossible. To be conceived at all, a thing must be conceived as having attributes. We can distinguish something from nothing, only by the power which the something has to act on our consciousness. The effects it mediately or immediately produces on our consciousness we attribute to it, and call its attributes; and the absence of these attributes is the absence of the terms in which the something is conceived, and involves the absence of a conception. What, now, are the attributes of Space? The only one which it is possible to think of as belonging to it is that of extension, and to credit it with this is to identify object and attribute. For extension and Space are convertible terms: by extension, as we ascribe it to surrounding objects, we mean occupancy of Space; and thus to say that Space is extended, is to say that Space occupies Space. How we are similarly unable to assign any attribute to Time, scarcely needs pointing out. Nor are Time and Space unthinkable as entities only from the absence of attributes. There is another peculiarity, familiar to most people, which equally excludes them from the category. All entities actually known as such, are limited; and even if we suppose ourselves either to know or to be able to conceive some unlimited entity, we necessarily in so classing it separate it from the class of limited entities. But of Space and Time we cannot assert either limitation or the absence of limitation. We find ourselves unable to form any mental image of unbounded Space; and yet are unable to imagine bounds beyond which there is no Space. Similarly at the other extreme: it is impossible to think of a limit to the divisibility of Space; yet equally impossible to think of its infinite divisibility. And, without stating them, it will be seen that we labour under like impotences in respect to Time. Thus we cannot conceive Space and Time as entities, and are equally disabled from conceiving them as either the attributes of entities or as non-entities. We are compelled to think of them as existing, and yet cannot bring them within those conditions under which existences are represented in thought.

Shall we then take refuge in the Kantian doctrine? Shall we say that Space and Time are forms of the intellect, — "a priori laws or conditions of the conscious mind?" To do this is to escape from great difficulties by rushing into greater. The proposition with which Kant's philosophy sets out, verbally intelligible though it is, cannot by any effort be rendered into thought — cannot be interpreted into an idea properly so called, but stands merely for a pseud-idea. In the first place, to assert that Space and Time are subjective conditions is, by implication, to assert that they are not objective realities: if the Space and Time present to our minds belong to the ego, then of necessity they do not belong to the non-ego. Now it is impossible to think this. The very fact on which Kant bases his hypothesis — namely that our consciousness of Space and Time cannot be suppressed — testifies as much; for that consciousness of Space and Time which we cannot rid ourselves of, is the consciousness of them as existing objectively. It is useless to reply that such an inability must inevitably result if they are subjective forms. The question here is — What does consciousness directly testify? And the direct testimony of consciousness is, that Time and Space are not within the mind but without the mind; and so absolutely independent that we cannot conceive them to become non-existent even supposing the mind to become non-existent. Besides being positively unthinkable in what it tacitly denies, the theory of Kant is equally unthinkable in what it openly affirms. It is not simply that we cannot combine the thought of Space with the thought of our own personality, and contemplate the one as a property of the other — though our inability to do this would prove the inconceivableness of the hypothesis — but it is that the hypothesis carries in itself the proof of its own inconceivableness. For if Space and Time are forms of intuition, they can never be intuited; since it is impossible for anything to be at once the form of intuition and the matter of intuition. That Space and Time are objects of consciousness, Kant emphatically asserts by saying that it is impossible to suppress the consciousness of them. How then, if they are objects of consciousness, can they at the same time be conditions of consciousness? If Space and Time are the conditions under which we think, then when we think of Space and Time themselves, our thoughts must be unconditioned; and if there can thus be unconditioned thoughts, what becomes of the theory?

It results, therefore, that Space and Time are wholly incomprehensible. The immediate knowledge which we seem to have of them proves, when examined, to be total ignorance. While our belief in their objective reality is insurmountable, we are unable to give any rational account of it. And to posit the alternative belief (possible to state but impossible to realize) is merely to multiply irrationalities.

§16. Were it not for the necessities of the argument, it would be inexcusable to occupy the reader's attention with the threadbare, and yet unended, controversy respecting the divisibility of matter. Matter is either infinitely divisible or it is not: no third possibility can be named. Which of the alternatives shall we accept? If we say that Matter is infinitely divisible, we commit ourselves to a supposition not realizable in thought. We can bisect and re-bisect a body, and continually repeating the act until we reduce its parts to a size no longer physically divisible, may then mentally continue the process. To do this, however, is not really to conceive the infinite divisibility of matter, but to form a symbolic conception not admitting of expansion into a real one, and not admitting of other verification. Really to conceive the infinite divisibility of matter, is mentally to follow out the divisions to infinity. and to do this would require infinite time. On the other hand, to assert that matter is not infinitely divisible, is to assert that it is reducible to parts which no power can divide; and this verbal supposition can no more be represented in thought than the other. For each of such ultimate parts, did they exist, must have an under and an upper surface, a right and a left side, like any larger fragment. Now it is impossible to imagine its sides so near that no plane of section can be conceived between them; and however great be the assumed force of cohesion, it is impossible to shut out the idea of a greater force capable of overcoming it. So that to human intelligence the one hypothesis is no more acceptable than the other; and yet the conclusion that one or other must agree with the fact, seems to human intelligence unavoidable.

Again, let us ask whether substance has anything like that extended solidity which it presents to our consciousness. The portion of space occupied by a piece of metal, seems to eyes and fingers perfectly filled: we perceive a homogeneous, resisting mass, without any breach of continuity. Shall we then say that Matter is actually as solid as it appears? Shall we say that whether it consists of an infinitely divisible element or of units which cannot be further divided, its parts are everywhere in actual contact? To assert as much entangles us in insuperable difficulties. Were Matter thus absolutely solid it would be — what it is not — absolutely incompressible; since compressibility, implying the nearer approach of constituent parts, is not thinkable unless there is unoccupied space among the parts.

The supposition that Matter is absolutely solid being untenable, there presents itself the Newtonian supposition, that it consists of solid atoms not in contact but acting on one another by attractive and repulsive forces, varying with the distances. To assume this, however, merely shifts the difficulty. For granting that Matter as we perceive it, is made up of dense extended units attracting and repelling, the question still arises — What is the constitution of these units? We must regard each of them as a small piece of matter. Looked at through a mental microscope, each becomes a mass such as we have just been contemplating. Just the same inquiries may be made respecting the parts of which each atom consists; while just the same difficulties stand in the way of every answer. Even were the hypothetical atom assumed to consist of still minuter ones, the difficulty would reappear at the next step; and so on perpetually.

Boscovich's conception yet remains to us. Seeing that Matter could not, as Leibnitz suggested, be composed of unextended monads (since the juxtaposition of an infinity of points having no extension could not produce that extension which matter possesses), and perceiving objections to the view entertained by Newton, Boscovich proposed an intermediate theory. This theory is that the constituents of Matter are centres of force — points without dimensions — which attract and repel one another in such wise as to be kept at specific distances apart. And he argues, mathematically, that the forces possessed by such centres might so vary with the distances that, under given conditions, the centres would remain in stable equilibrium with definite interspaces; and yet, under other conditions, would maintain larger or smaller interspaces. This speculation, however, escapes all the inconceivabilities above indicated by merging them in the one inconceivability with which it sets cut. A centre of force absolutely without extension is unthinkable. The idea of resistance cannot be separated in thought from the idea of something which offers resistance, and this something must be thought of as occuppying space. To suppose that central forces can reside in points having positions only, with nothing to mark their positions — points in no respect distinguishable from surrounding points which are not centres of force — is beyond human power.

But though the conception of Matter as consisting of dense indivisible units is symbolic, and cannot by any effort be thought out, it may yet be supposed to find indirect verification in the truths of chemistry. These, it is argued, necessitate the belief that Matter consists of particles of specific weights, and therefore of specific sizes. The law of definite proportions seems impossible on any other condition than the existence of ultimate atoms; and though the combining weights of the respective elements are termed by chemists their "equivalents," for the purpose of avoiding a questionable assumption, we are unable to think of the combination of such definite weights, without supposing it to take place between definite molecules. Thus it would appear that the Newtonian view is at any rate preferable to that of Boscovich. A disciple of Boscovich, however, may reply that his master's theory is involved in that of Newton, and cannot indeed be escaped. "What holds together the parts of these ultimate atoms?" he may ask. "A cohesive force," his opponent must answer. "And what," he may continue, "holds together the parts of any fragments into which, by sufficient force, an ultimate atom might be broken?" Again the answer must be — a cohesive force. "And what," he may still ask, "if the ultimate atom were reduced to parts as small in proportion to it, as it is in proportion to a tangible mass of matter — what must give each part the ability to sustain itself?" Still there is no answer but — a cohesive force. Carry on the mental process and we can find no limit until we arrive at the symbolic conception of centres of force without any extension.

Matter then, in its ultimate nature, is as absolutely incomprehensible as Space and Time. Whatever supposition we frame leaves us nothing but a choice between opposite absurdities.*

<* To discuss Lord Kelvin's hypothesis of vortex-atoms, from the scientific point of view, is beyond my ability. From the philosophical point of view, however I may say that since it postulates a homogeneous medium which is strictly continuous (non-molecular), which is incompressible, which is a perfect fluid in the sense of having no viscosity, and which has inertia, it sets out with what appears to me an inconceivability. A fluid which has inertia, implying mass, and which is yet absolutely frictionless. so that its parts move among one another without any loss of motion, cannot be truly represented in consciousness. Even were it otherwise, the hypothesis is held by Prof. Clerk Maxwell to be untenable (see art. "Atom," Ency. Brit.).>

§17. A body impelled by the hand is perceived to move, and to move in a definite direction; doubt about its motion seems impossible. Yet we not only may be, but usually are, quite wrong in both these judgments. Here, for instance, is a ship which we will suppose to be anchored at the equator with her head to the West. When the captain walks from stem to stern, in what direction does he move? East is the obvious answer — an answer which for the moment may pass without criticism. But now the anchor is heaved, and the vessel sails to the West with a velocity equal to that at which the captain walks. In what direction does he now move when he goes from stem to stern? You cannot say East, for the vessel is carrying him as fast towards the West as he walks to the East; and you cannot say West for the converse reason In respect to things outside the vessel he is stationary, though to all on board he seems to be moving. But now are we quite sure of this conclusion? — Is he really stationary? On taking into account the Earth's motion round its axis, we find that he is travelling at the rate of 1000 miles per hour to the East; so that neither the perception of one who looks at him, nor the inference of one who allows for the ship's motion, is anything like right. Nor indeed, on further consideration, do we find this revised conclusion to be much better. For we have not allowed for the Earth's motion in its orbit. This being some 68,000 miles per hour, it follows that, assuming the time to be midday, he is moving, not at the rate of 1000 miles per hour to the East, but at the rate of 67,000 miles per hour to the East. Nay not even now have we discovered the true rate and the true direction of his movement. With the Earth's progress in its orbit, we have to join that of the whole Solar system towards the constellation Hercules. When we do this, we perceive that he is moving neither East nor West, but in a line inclined to the plane of the Ecliptic, and at a velocity greater or less (according to the time of the year) than that above named. And were the constitution of our Sidereal System fully known, we should probably discover the direction and rate of his actual movement to differ considerably even from these. Thus we are taught that what we are conscious of is not the real motion of any object, either in its rate or direction, but merely its motion as measured from an assigned position — either our own or some other. Yet in this very process of concluding that the motions we perceive are not the real motions, we tacitly assume that there are real motions. We take for granted that there is an absolute course and an absolute velocity and we find it impossible to rid ourselves of this idea. Nevertheless, absolute motion cannot even be imagined, much less known. Apart from those marks in space which we habitually associate with it, motion is unthinkable. For motion is change of place; but in space without marks, change of place is inconceivable, because place itself is inconceivable. Place can be conceived only by reference to other places; and in the absence of objects dispersed through space, a place could be conceived only in relation to the limits of space; whence it follows that in unlimited space, place cannot be conceived — all places must be equidistant from boundaries which do not exist. Thus while obliged to think that there is an absolute motion, we find absolute motion cannot be represented in thought.

Another insuperable difficulty presents itself when we contemplate the transfer of Motion. Habit blinds us to the marvellousness of this phenomenon. Familiar with the fact from childhood, we see nothing remarkable in the ability of a moving thing to generate movement in a thing that is stationary. It is, however, impossible to understand it. In what respect does a body after impact differ from itself before impact? What is this added to it which does not sensibly affect any of its properties and yet enables it to traverse space? Here is an object at rest and here is the same object moving. In the one state it has no tendency to change its place, but in the other it is obliged at each instant to assume a new position. What is it which will for ever go on producing this effect without being exhausted? and how does it dwell in the object? The motion you say has been communicated. But how? — What has been communicated? The striking body has not transferred a thing to the body struck; and it is equally out of the question to say that it has transferred an attribute. What then has it transferred?

Once more there is the old puzzle concerning the connexion between Motion and Rest. A body travelling at a given velocity cannot be brought to a state of rest, or no velocity, without passing through all intermediate velocities. It is quite possible to think of its motion as diminishing insensibly until it becomes infinitesimal; and many will think equally possible to pass in thought from infinitesimal motion to no motion. But this is an error. Mentally follow out the decreasing velocity as long as you please, and there still remains some velocity; and the smallest movement is separated by an impassable gap from no movement. As something, however minute, is infinitely great in comparison with nothing; so is even the least conceivable motion infinite as compared with rest.

Thus neither when considered in connexion with Space, nor when considered in connexion with Matter, nor when considered in connexion with Rest, do we find that Motion is truly cognizable. All efforts to understand its essential nature do but bring us to alternative impossibilities of thought.

§18. On lifting a chair the force exerted we regard as equal to that antagonistic force called the weight of the chair, and we cannot think of these as equal without thinking of them as like in kind; since equality is conceivable only between things that are connatural. Yet, contrariwise, it is incredible that the force existing in the chair resembles the force present to our minds. It scarcely needs to point out that since the force as known to us is an affection of consciousness, we cannot conceive the force to exist in the chair under the same form without endowing the chair with consciousness. So that it is absurd to think of Force as in itself like our sensation of it, and yet necessary so to think of it if we represent it in consciousness at all.

How, again, can we understand the connexion between Force and Matter? Matter is known to us only through its manifestations of Force: abstract its resistance mediately or immediately offered and there remains nothing but empty extension. Yet, on the other hand, resistance is equally unthinkable apart from Matter — apart from something extended. Not only are centres of force devoid of extension unimaginable, but we cannot imagine either extended or unextended centres of force to attract and repel other such centres at a distance, without the intermediation of some kind of matter. The hypothesis of Newton, equally with that of Boscovich, is open to the charge that it supposes one thing to act on another through empty space — a supposition which cannot be represented in thought. This charge is indeed met by introducing a hypothetical fluid existing among the atoms or centres. But the problem is not thus solved: it is simply shifted, and reappears when the constitution of this fluid is inquired into. How impossible it is to elude the difficulty is best seen in the case of astronomical forces. The Sun gives us sensations of light and heat; and we have ascertained that between the cause as existing in the Sun, and the effect as experienced on the Earth, a lapse of eight minutes occurs: whence unavoidably result in us the conceptions of both a force and a motion. So that for assuming a luminiferous ether, there is the defence, not only that the exercise of force through 92,000,000 of miles of absolute vacuum is inconceivable, but also that it is impossible to conceive motion in the absence of something moved. Similarly in the case of gravitation. Newton described himself as unable to think that the attraction of one body for another at a distance, could be exerted in the absence of an intervening medium. But now let us ask how much the forwarder we are if an intervening medium be assumed. This ether whose undulations according to the received hypothesis constitute heat and light, and which is the vehicle of gravitation — how is it constituted? We must regard it in the way that physicists usually regard it, as composed of atoms or molecules which attract and repel one another: infinitesimal it may be in comparison with those of ordinary matter, but still atoms or molecules. And remembering that this ether is imponderable, we are obliged to conclude that the ratio between the interspaces of these atoms and the atoms themselves is immense. Hence we have to conceive these infinitesimal molecules acting on one another through relatively vast distances. How is this conception easier than the other? We still have mentally. to represent a body as acting where it is not, and in the absence of anything by which its action may be transferred; and what matters it whether this takes place on a large or a small scale? Thus we are obliged to conclude that matter, whether ponderable or imponderable, and whether aggregated or in its hypothetical units, acts on matter through absolutely vacant space; and yet this conclusion is unthinkable.

Another difficulty of conception, converse in nature but equally insurmountable, must be added. If, on the one hand, we cannot in thought see matter acting upon matter through vacant space; on the other hand, it is incomprehensible that the gravitation of one particle of matter towards another, and towards all others, should be the same whether the intervening space is filled with matter or not. I lift from the ground, and continue to hold, a pound weight. Now, into the vacancy between it and the ground, is introduced a mass of matter of any kind whatever, in any state whatever; and the gravitation of the weight is entirely unaffected. Each individual of the infinity of particles composing the Earth acts on the pound in absolutely the same way, whatever intervenes, or if nothing intervenes. Through eight thousand miles of the Earth's substance, each molecule at the antipodes affects each molecule of the weight, in utter indifference to the fullness or emptiness of the space between them. So that each portion of matter in its dealings with remote portions, treats all intervening portions as though they did not exist; and yet, at the same time, it recognizes their existence with scrupulous exactness in its direct dealings with them.

While then it is impossible to form any idea of Force in itself, it is equally impossible to comprehend its mode of exercise.

§19. Turning now from the outer to the inner world, let us contemplate, not the agencies to which we ascribe our subjective modifications, but the subjective modifications themselves. These constitute a series. Difficult as we find it distinctly to individualize them, it is nevertheless beyond question that our states of consciousness occur in succession.

Is this chain of states of consciousness infinite or finite? We cannot say infinite; not only because we have indirectly reached the conclusion that there was a period when it commenced, but also because all infinity is inconceivable — an infinite series included. If we say finite we say it inferentially; for we have no direct knowledge of either of its ends. Go back in memory as far as we may, we are wholly unable to identify our first states of consciousness. Similarly at the other extreme. We infer a termination to the series at a future time, but cannot directly know it; and we cannot really lay hold of that temporary termination reached at the present moment. For the state of consciousness recognized by us as our last, is not truly our last. That any mental affection may be known as one of the series, it must be remembered — represented in thought, not presented. The truly last state of consciousness is that which is passing in the very act of contemplating a state just past — that in which we are thinking of the one before as the last. So that the proximate end of the change eludes us, as well as the remote end.

"But," it may be said, "though we cannot directly know consciousness to be finite in duration, because neither of its limits can be actually reached, yet we can very well conceive it to be so." No: not even this is true. We cannot conceive the terminations of that consciousness which alone we really know — our own — any more than we can perceive its terminations. For in truth the two acts are here one. In either case such terminations must be, as above said, not presented in thought, but represented; and they must be represented as in the act of occurring. Now to represent the termination of consciousness as occurring in ourselves, is to think of ourselves as contemplating the cessation of the last state of consciousness; and this implies a supposed continuance of consciousness after its last state, which is absurd.

Hence, while we are unable to believe or to conceive that the duration of consciousness is infinite, we are equally unable either to know it as finite, or to conceive it as finite: we can only infer from indirect evidence that it is finite.

§20. Nor do we meet with any greater success when, instead of the extent of consciousness, we consider its substance. The question — What is this that thinks? admits of no better solution than the question to which we have just found none but inconceivable answers.

The existence of each individual as known to himself, has always been held the most incontrovertible of truths. To say — "I am as sure of it as I am sure that I exist," is, in common speech, the most emphatic expression of certainty. And this fact of personal existence, testified to by the universal consciousness of men, has been made the basis of more philosophies than one.

Belief in the reality of self cannot, indeed, be escaped while normal consciousness continues. What shall we say of these successive impressions and ideas which constitute consciousness? Are they affections of something called mind, which, as being the subject of them, is the real ego? If we say this we imply that the ego is an entity. Shall we assert that these impressions and ideas are not the mere superficial changes wrought on some thinking substance, but are themselves the very body of this substance — are severally the modified forms which it from moment to moment assumes? This hypothesis, equally with the foregoing, implies that the conscious self exists as a permanent continuous being; since modifications necessarily involve something modified. Shall we then betake ourselves to the sceptic's position, and argue that our impressions and ideas themselves are to us the only existences, and that the personality said to underlie them is a fiction? We do not even thus escape; since this proposition, verbally intelligible but really unthinkable, itself makes the assumption which it professes to repudiate. For how can consciousness be wholly resolved into impressions and ideas, when an impression of necessity imples something impressed? Or again, how can the sceptic who has decomposed his consciousness into impressions and ideas, explain the fact that he considers them as his impressions and ideas? Or once more, if, as he must, he admits that he has an impression of his personal existence, what warrant can he show for rejecting this impression as unreal while he accepts all his other impressions as real?

But now, unavoidable as is this belief, it is yet a belief admitting of no justification by reason: nay, indeed, it is a belief which reason, when pressed for a distinct answer, rejects. One of the most recent writers who has touched on this question — Mr. Mansel — does, indeed, contend that in the consciousness of self we have a piece of real knowledge. His position is that "let system makers say what they will, the unsophisticated sense of mankind refuses to acknowledge that mind is but a bundle of states of consciousness, as matter is (possibly) a bundle of sensible qualities." But this position does not seem a consistent one for a Kantist, who pays but small respect to "the unsophisticated sense of mankind" when it testifies to the objectivity of space. Moreover, it may readily be shown that a cognition of self, properly so called, is negatived by those laws of thought which he emphasizes. The fundamental condition to all consciousness, insisted upon by Mr. Mansel in common with Sir William Hamilton and others, is the antithesis of subject and object. On this "primitive dualism of consciousness," "from which the explanations of philosophy must take their start," Mr. Mansel founds his refutation of the German absolutists. But now what is the corollary, as bearing on the consciousness of self? The mental act in which self is known implies, like every other mental act, a perceiving subject and a perceived object. If, then, the object perceived is self, what is the subject that perceives? or if it is the true self which thinks, what other self can it be that is thought of? Clearly, a true cognition of self implies a state in which the knowing and the known are one — in which subject and object are identified; and this Mr. Mansel rightly holds to be the annihilation of both.

So that the personality of which each is conscious, and the existence of which is to each a fact beyond all others the most certain, is yet a thing which cannot be known at all, in the strict sense of the word.

§21. Ultimate Scientific Ideas, then, are all representative of realities that cannot be comprehended. After no matter how great a progress in the colligation of facts and the establishment of generalizations ever wider and wider, the fundamental truth remains as much beyond reach as ever. The explanation of that which is explicable, does but bring into greater clearness the inexplicableness of that which remains behind. Alike in the external and the internal worlds, the man of science sees himself in the midst of perpetual changes of which he can discover neither the beginning nor the end. If he allows himself to entertain the hypothesis that the Universe originally existed in a diffused form, he finds it impossible to conceive how this came to be so; and equally, if he speculates on the future, he can assign no limit to the grand succession of phenomena ever unfolding themselves before him. In like manner if he looks inward he perceives that both ends of the thread of consciousness are beyond his grasp. Neither end can be represented in thought. When, again, he turns from the succession of phenomena, external or internal, to their intrinsic nature, he is just as much at fault. Supposing him in every case able to resolve the appearances, properties, and movements of things, into manifestations of Force in Space and Time; he still finds that Force, Space, and Time pass all understanding. Similarly, though analysis of mental actions may finally bring him down to sensations, as the original materials out of which all thought is woven, yet he is little forwarder; for he can give no account either of sensations themselves or of that which is conscious of sensations. Objective and subjective things he thus ascertains to be alike inscrutable in their substance and genesis. In all directions his investigations eventually bring him face to face with an insoluble enigma; and be ever more clearly perceives it to be an insoluble enigma. He learns at once the greatness and the littleness of the human intellect — its power in dealing with all that comes within the range of experience, its impotence in dealing with all that transcends experience. He, more than any other, truly knows that in its ultimate nature nothing can be known.

Chapter 4

The Relativity of all Knowledge

§22. The same conclusion is thus arrived at from whichever point we set out. Ultimate religious ideas and ultimate scientific ideas, alike turn out to be merely symbols of the actual, not cognitions of it.

The conviction, so reached, that human intelligence is incapable of absolute knowledge, is one that has been slowly gaining ground. Each new ontological theory, propounded in lieu of previous ones shown to be untenable, has been followed by a new criticism leading to a new scepticism. All possible conceptions have been one by one tried and found wanting; and so the entire field of speculation has been gradually exhausted without positive result: the only result reached being the negative one above stated — that the reality existing behind all appearances is, and must ever be, unknown. To this conclusion almost every thinker of note has subscribed. "With the exception," says Sir William Hamilton, "of a few late Absolutist theorizers in Germany, this is, perhaps, the truth of all others most harmoniously re-echoed by every philosopher of every school." And among these he names — Protagoras, Aristotle, St. Augustin, Boethius, Averroes, Albertus Magnus, Gerson, Leo Hebraeus, Melancthon, Scaliger, Francis Piccolomini, Giordano Bruno, Campanella, Bacon, Spinoza, Newton, Kant.

It remains to point out how this belief may be established rationally, as well as empirically. Not only is it that, as in the earlier thinkers above named, a vague perception of the inscrutableness of things in themselves results from discovering the illusiveness of sense-impressions; and not only is it that, as shown in the foregoing chapters, experiments evolve alternative impossibilities of thought out of every fundamental conception; but it is that the relativity of our knowledge may be proved analytically. The induction drawn from general and special experiences, may be confirmed by a deduction from the nature of our intelligence. Two ways of reaching such a deduction exist. Proof that our cognitions are not, and never can be, absolute, is obtainable by analyzing either the product or thought, or the process of thought. Let us analyze each.

§23. If, when walking through the fields some day in September, you hear a rustle a few yards in advance, and on observing the ditch-side where it occurs, see the herbage agitated, you will probably turn towards the spot to learn by what this sound and motion are produced. As you approach there flutters into the ditch a partridge; on seeing which your curiosity is satisfied — you have what you call an explanation of the appearances. The explanation, mark, amounts to this; that whereas throughout life you have had countless experiences of disturbance among small stationary bodies, accompanying the movement of other bodies among them, and have generalized the relation between such disturbances and such movements, you consider this particular disturbance explained, on finding it to present an instance of the like relation. Suppose you catch the partridge; and, wishing to ascertain why it did not escape, examine it, and find at one spot a trace of blood on its feathers. You now understand, as you say, what has disabled the partridge. It has been wounded by a sportsman — adds another case to the cases already seen by you, of birds being killed or injured by the shot discharged at them from fowling-pieces. And in assimilating this case to other such cases, consists your understanding of it. But now, on consideration, a difficulty suggests itself. Only a single shot has struck the partridge, and that not in a vital place: the wings are uninjured, as are also those muscles which move them; and the creature proves by its struggles that it has abundant strength. Why then, you inquire of yourself, does it not fly? Occasion favouring, you put the question to an anatomist, who furnishes you with a solution. He points out that this solitary shot has passed close to the place at which the nerve supplying the wing-muscles of one side, diverges from the spine; and explains that a slight injury to this nerve, extending even to the rupture of a few fibres, may by preventing a perfect co-ordination in the actions of the two wings, destroy the power of flight. You are no longer puzzled. But what has happened? — what has changed your state from one of perplexity to one of comprehension? Simply the disclosure of a class of previously known cases, along with which you can include this case. The connexion between lesions of the nervous system and paralysis of limbs has been already many times brought under your notice; and you here find a relation of cause and effect that is essentially similar.

Let us suppose you are led to ask the anatomist questions about some organic actions which, remarkable though they are, you had not before cared to understand. How is respiration effected? You ask — why does air periodically rush into the lungs? The answer is that influx of air is caused by an enlargement of the thoracic cavity, due, partly to depression of the diaphragm, partly to motion of the ribs. But how can these bony hoops move, and how does motion of them enlarge the cavity? In reply the anatomist explains that though attached by their ends the ribs can move a little round their points of attachment; he then shows you that the plane of each pair of ribs makes an acute angle with the spine; that this angle widens when the sternal ends of the ribs are raised; and he makes you realize the consequent dilatation of the cavity, by pointing out how the area of a parallelogram increases as its angles approach to right angles: you understand this special fact when you see it to be an instance of a general geometrical fact. There still arises, however, the question — why does the air rush into this enlarged cavity? To which comes the answer that, when the thoracic cavity is enlarged, the contained air, partially relieved from pressure, expands, and so loses some of its resisting Power; that hence it opposes to the pressure of the external air a less pressure; and that as air, like every other fluid, presses equally in all directions, motion must result along any line in which the resistance is less than elsewhere; whence follows an inward current. And this interpretation you recognize as one, when a few facts of like kind, exhibited more plainly in a visible fluid such as water, are cited in illustration. Again, after being shown that the limbs are compound levers acting in essentially the same way as levers of iron, you would consider yourself as having obtained a partial rationale of animal movements. The contraction of a muscle, seeming before quite unaccountable, would seem less unaccountable were you shown how, by a galvanic current, a series of soft iron magnets could be made to shorten itself through the attraction of each magnet for its neighbours: — an alleged analogy which especially answers the purpose of our argument, since, whether real or fancied, it equally illustrates the mental illumination that results on finding a class of cases within which a particular case may perhaps be included. Similarly when you learn that animal heat arises from chemical combination, and so may be classed with heat evolved in other chemical combinations — when you learn that the absorption of nutrient liquids through the coats of the intestines is an instance of osmotic action — when you learn that the changes undergone by food during digestion, are like changes artificially producible in the laboratory; you regard yourself as knowing something about the natures of these phenomena.

Observe now what we have been doing. We began with special and concrete facts. In explaining each, and afterwards explaining the general facts of which they are instances, we have got down to certain highly general facts: — to a geometrical principle, to a simple law of mechanical action, to a law of fluid equilibrium — to truths in physics, in chemistry, in thermology. The particular phenomena with which we set out have been merged in larger and larger groups of phenomena; and as they have been so merged, we have arrived at solutions we consider profound in proportion as this process has been carried far. Still deeper explanations are simply further steps in the same direction. When, for instance, it is asked why the law of action of the lever is what it is, or why fluid equilibrium and fluid motion exhibit the relations they do, the answer furnished by mathematicians consists in the disclosure of the principle of virtual velocities — a principle holding true alike in fluids and solids — a principle under which the others are comprehended.

Is this process limited or unlimited? Can we go on for ever explaining classes of facts by including them in larger classes; or must we eventually come to a largest class? The supposition that the process is unlimited, were any one absurd enough to espouse it, would still imply that an ultimate explanation could not be reached, since infinite time would be required to reach it. While the unavoidable conclusion that it is limited, equally implies that the deepest fact cannot be understood. For if the successively deeper interpretations of Nature which constitute advancing knowledge, are merely successive inclusions of special truths in general truths, and of general truths in truths still more general; it follows that the most general truth, not admitting of inclusion in any other, does not admit of interpretation. Of necessity, therefore, explanation must eventually bring us down to the inexplicable. Comprehension must become something other than comprehension, before the ultimate fact can be comprehended.

§24. The inference which is thus forced on us when we analyze the product of thought, as exhibited objectively in scientific generalizations, is equally forced on us by an analysis of the process of thought, as exhibited subjectively in consciousness. The demonstration of the relative character of our knowledge, as deduced from the nature of intelligence, has been brought to its most definite shape by Sir William Hamilton. I cannot here do better than extract from his essay on the "Philosophy of the Unconditioned," the passage containing the substance of his doctrine.

"The unconditionally unlimited, or the Infinite, the unconditionally limited, or the Absolute, cannot positively be construed to the mind; they can be conceived, only by a thinking away from, or abstraction of, those very conditions under which thought itself is realized; consequently, the notion of the Unconditioned is only negative, — negative of the conceivable itself. For example, on the one hand we can positively conceive, neither an absolute whole, that is, a whole so great, that we cannot also conceive it as a relative part of a still greater whole; nor an absolute part, that is, a part so small, that we cannot also conceive it as a relative whole, divisible into smaller parts. On the other hand, we cannot positively represent, or realize, or construe to the mind (as here understanding and imagination coincide), an infinite whole, for this could only be done by the infinite synthesis in thought of finite wholes, which would itself require an infinite time for its accomplishment; nor, for the same reason, can we follow out in thought an infinite divisibility of parts. The result is the same, whether we apply the process to limitation in space, in time, or in degree. * * *

"As the conditionally limited (which we may briefly call the conditioned) is thus the only possible object of knowledge and of positive thought — thought necessarily supposes conditions. To think is to condition; and conditional limitation is the fundamental law of the possibility of thought. For, as the greyhound cannot outstrip his shadow, nor (by a more appropriate simile) the eagle outsoar the atmosphere in which he floats, and by which alone he may be supported; so the mind cannot transcend that sphere of limitation, within and through which exclusively the possibility of thought is realized. * * * How, indeed, it could ever be doubted that thought is only of the conditioned, may well be deemed a matter of the profoundest admiration. Thought cannot transcend consciousness; consciousness is only possible under the antithesis of a subject and object of thought, known only in correlation, and mutually limiting each other; while, independently of this, all that we know either of subject or object, either of mind or matter, is only a knowledge in each of the particular, of the plural, of the different, of the modified, of the phaenomenal. We admit that the consequence of this doctrine is, — that philosophy, if viewed as more than a science of the conditioned, is impossible. Departing from the particular, we admit, that we can never, in our highest generalizations, rise above the finite; that our knowledge, whether of mind or matter, can be nothing more than a knowledge of the relative manifestations of an existence, which in itself it is our highest wisdom to recognize aS beyond the reach of philosophy. * * *

"We are thus taught the salutary lesson, that the capacity of thought is not to be constituted into the measure of existence; and are warned from recognizing the domain of our knowledge as necessarily co-extensive with the horizon of our faith. And by a wonderful revelation, we are thus, in the very consciousness of our inability to conceive aught above the relative and finite, inspired with a belief in the existence of something unconditioned beyond the sphere of all comprehensible reality."

Clear and conclusive as this statement of the case appears when carefully studied, it is expressed in so abstract a manner as to be not very intelligible to the general reader. A more popular presentation of it. with illustrative applications, as given by Mr. Mansel in his Limits of Religious Thought, will make it more fully understood. The following extracts, which I take the liberty of making from his pages, will suffice.

"The very conception of consciousness in whatever mode it may be manifested, necessarily implies distinction between one object and another. To be conscious, we must be conscious of something; and that something can only be known, as that which it is, by being distinguished from that which it is not. But distinction is necessarily imitation; for, if one object is to be distinguished from another, it must possess some form of existence which the other has not, or it must not possess some form which the other has. * * * If all thought is limitation; — if whatever we conceive is, by the very act of conception, regarded as finite, — the infinite, from a human point of view, is merely a name for the absence of those conditions under which thought is possible. To speak of a Conception of the Infinite is, therefore, at once to affirm those conditions and to deny them. The contradiction, which we discover in such a conception, is only that which we have ourselves placed there, by tacitly assuming the conceivability of the inconceivable. The condition of consciousness is distinction; and condition of distinction is limitation. We can have no consciousness of Being in general which is not some Being in particular: a thing, in consciousness, is one thing out of many. In assuming the possibility of an infinite object of consciousness, I assume, therefore, that it is at the same time limited and unlimited; — actually something, without which it could not be an object of consciousness, and actually nothing, without which it could not be infinite. * * *

"A second characteristic of Consciousness is, that it is only possible in the form of a relation. There must be a Subject, or person conscious, and an Object, or thing of which he is conscious. There can be no consciousness without the union of these two factors; and, in that union, each exists only as it is related to the other. The subject is a subject, only in so far as it is conscious of an object; the object is an object, only in so far as it is apprehended by a subject: and the destruction of either is the destruction of consciousness itself. It is thus manifest that a consciousness of the Absolute is equally self-contradictory with that of the Infinite. To be conscious of the Absolute as such, we must know that an object, which is given in relation to our consciousness, is identical with one which exists in its own nature, out of all relation to consciousness. But to know this identity, we must be able to compare the two together; and such a comparison is itself a contradiction. We are in fact required to compare that of which we are conscious with that of which we are not conscious; the comparison itself being an act of consciousness, and only possible through the consciousness of both its objects. It is thus manifest that, even if we could be conscious of the absolute we could not possibly know that it is the absolute: and, as we can be conscious of an object as such, only by knowing it to be what it is, this is equivalent to an admission that we cannot be conscious of the absolute at all. As an object of COnsciousness, every thing is necessarily relative; and what a thing may be out of consciousness no mode of consciousness can tell us. * * *

"This contradiction, again, admits of the same explanation as the former, * * * Existence, as we conceive it, is but a name for the several ways in which objects are presented to our consciousness, — a general term, embracing a variety of relations. The Absolute, on the other hand, is a term expressing no object of thought, but only a denial of the relation by which thought is constituted."

Here let me point out how the same general inference may be evolved from another fundamental condition to thought, omitted by Sir W. Hamilton and not supplied by Mr. Mansel; — a condition which, under its obverse aspect, we have already contemplated in the last section. Every complete act of consciousness, besides distinction and relation, also implies likeness. Before it can constitute a piece of knowledge, or even become an idea, a mental state must be known not only as separate in kind or quality from certain foregoing states to which it is known as related by succession, but it must further be known as of the same kind or quality with certain other foregoing states. That organization of changes which constitutes thinking, involves continuous integration as well as continuous differentiation. Were each new affection of the mind perceived simply as an affection in some way contested with preceding ones — were there but a chain of impressions, each of which as it arose was merely distinguished from its predecessors; consciousness would be a chaos. To produce that orderly consciousness which we call intelligence, there requires the assimilation of each impression to others that occurred earlier in the series. Both the successive mental states, and the successive relations which they bear to one another, must be classified; and classification involves not only a parting of the unlike, but also a binding together of the like. In brief, a true cognition is possible only through an accompanying recognition. Should it be objected that if so there cannot be a first cognition, and hence there can be no cognition, the reply is that cognition proper arises gradually — that during the first stage of incipient intelligence, before the feelings produced by intercourse with the outer world have been put into order, there are no cognitions; and that, as every infant shows us, these slowly emerge out of the confusion of unfolding consciousness as fast as the experiences are arranged into groups — as fast as the most frequently repeated sensations, and their relations to one another, become familiar enough to admit of their recognition as such or such, whenever they recur. Should it be further objected that if cognition presupposes recognition, there can be no cognition, even by an adult, of an object never before seen; there is still the sufficient answer that in so far as it is not assimilated to previously-seen objects it is not known, and that it is known only in so far as it is assimilated to them. Of this paradox the interpretation is, that an object is classifiable in various ways with various degress of completeness. An animal hitherto unknown (mark the word), though not referable to any established species or genus, is yet recognized as belonging to one of the larger divisions-mammals, birds, reptiles, or fishes; or should it be so anomalous that its alliance with any of these is not determinable, it may yet be classed as vertebrate or invertebrate; or if it be one of those organisms in which it is doubtful whether the animal or vegetal traits predominate, it is still known as a living body. Even should it be questioned whether it is organic, it remains beyond question that it is a material object, and it is cognized by being recognized as such. Whence it is clear that a thing is perfectly known only when it is in all respects like certain things previously observed. that in proportion to the number of respects in which it is unlike them, is the extent to which it is unknown; and that hence when it has absolutely no attribute in common with anything else, it must be absolutely beyond the bound of knowledge.

Observe the corollary which here concerns us. A cognition of the Real, as distinguished from the Phenomenal, must, if it exists, conform to this law of cognition in general. The First Cause, the Infinite, the Absolute, to be known at all, must be classed. To be positively thought of, it must be thought of as such or such — as of this or that kind. Can it be like in kind to anything of which we have experience? Obviously not. Between the creating and the created, there must be a distinction transcending any of the distinctions between different divisions of the created. That which is UnCauSed cannot be assimilated to that which is caused: the two being, in the very naming, antithetically opposed. The Infinite cannot be grouped along with something finite; since, in being so grouped, it must be regarded as not infinite. It is impossible to put the Absolute in the same category with anything relative, so long as the Absolute is defined as that of which no necessary relation can be predicated. Is it then that the Actual, though unthinkable by classification with the Apparent, is thinkable by classification with itself? This supposition is equally absurd with the other. It implies the plurality of the First Cause, the Infinite, the Absolute; and this implication is self-contradictory. There cannot be more than one First Cause; seeing that the existence of more than one would involve the existence of something necessitating more than one, which something would be the true First Cause. How self-destructive is the assumption of two or more Infinites, is manifest on remembering that such Infinites, by limiting each other, would become finite. And similarly, an Absolute which existed not alone but along with other Absolutes, would no longer be an absolute but a relative. The Unconditioned therefore, as classable neither with any form of the conditioned nor with any other Unconditioned, cannot be classed at all. And to admit that it cannot be known as of such or such kind, is to admit that it is unknowable.

Thus, from the very nature of thought, the relativity of our knowledge is inferable in three ways. As we find by analyzing it, and as we see it objectively displayed in every proposition, a thought involves relation, difference, likeness. Whatever does not present each of these does not admit of cognition. And hence we may say that the Unconditioned, as presenting none of them, is trebly unthinkable.

§25. From yet another point of view we may discern the same great truth. If, instead of examining our intellectual powers directly as displayed in the act of thought, or indirectly as displayed in thought when expressed by words, we look at the connexion between the mind and the world, a like conclusion is forced on us. The very definition of Life, phenomenally considered, when reduced to its most abstract shape, discloses this ultimate implication.

All vital actions, considered not separately but in their ensemble, have for their final purpose the balancing of certain outer processes by certain inner processes. There are external forces having a tendency to bring the matter of which living bodies consist, into that stable equilibrium shown by inorganic bodies; there are internal forces by which this tendency is constantly antagonized; and the unceasing changes which constitute Life, may be regarded as incidental to the maintenance of the antagonism. For instance, to preserve the erect posture certain weights have to be neutralized by certain strains: each limb or other organ, gravitating to the Earth and pulling down the parts to which it is attached, has to be preserved in position by the tension of sundry muscles; or, in other words, the forces which would if allowed bring the body to the ground, have to be counterbalanced by other forces. Again, to keep up the temperature at a particular point, the external process of radiation and absorption of heat by the surrounding medium, must be met by a corresponding internal process of chemical combination, whereby more heat may be evolved; to which add that if from atmospheric changes the loss becomes greater or less, the production must become greater or less. Similarly throughout the organic actions at large.

In the lower kinds of life the adjustments thus maintained are direct and simple; as in a plant, the vitality of which mainly consists in osmotic and chemical actions responding to the co-existence of light, heat, water, and carbon-dioxide around it. But in animals, and especially in the higher orders of them, the adjustments become extremely complex. Materials for growth and repair not being, like those which plants require, everywhere present, but being widely dispersed and under special forms, have to be found, to be secured, and to be reduced to a fit state for assimilation. Hence the need for locomotion; hence the need for the senses; hence the need for prehensile and destructive appliances; hence the need for an elaborate digestive apparatus. Observe, however, that these complications are nothing but aids to the maintenance of the organic balance, in opposition to those physical, chemical, and other agencies which tend to overturn it. And observe, further, that while these complications aid this fundamental adaptation of inner to outer actions, they are themselves nothing but additional adaptations of inner to outer actions. For what are those movements by which a predatory creature pursues its prey, or by which its prey seeks to escape, but certain changes in the organism fitted to meet certain changes in its environment? What is that operation which constitutes the perception of a piece of food, but a particular correlation of nervous modifications, answering to a particular correlation of physical properties? What is that process by which food when swallowed is made fit for assimilation, but a set of mechanical and chemical actions responding to the mechanical and chemical characters of the food? Hence, while Life in its simplest form is the correspondence of certain inner physico-chemical actions with certain outer physico-chemical actions, each advance to a higher form of Life consists in a better preservation of this primary correspondence by the establishment of other correspondences.

So that, passing over its noumenal nature of which we know nothing, Life is definable as the continuous adjustment of internal relations to external relations. And when we so define it, we discover that the physical and the psychical life are equally comprehended by the definition. This which we call Intelligence, arises when the external relations to which the internal ones are adjusted become numerous, complex, and remote in time or space. Every advance in Intelligence essentially consists in the establishment of more varied, more complete, or more involved adjustments. And even the highest generalizations of science consist of mental relations of co-existence and sequence, so co-ordinated as exactly to tally with certain relations of co-existence and sequence that occur externally. A caterpillar, finding its way on to a plant having a certain odour, begins to eat — has inside of it an organic relation between a particular impression and a particular set of actions, answering to the relation outside of it between scent and nutriment. The sparrow, guided by the more complex correlation of impressions which the colour form, and movements of the caterpillar gave it, and guided by other correlations which measure the position and distance of the caterpillar, adjusts certain correlated muscular movements so as to seize the caterpillar. through a much greater distance is the hawk, hovering above, affected by the relations of shape and motion which the sparrow presents; and the much more complicated and prolonged series of related nervous and muscular changes, gone through in correspondence with the sparrow's changing relations of position, finally succeed when they are precisely adjusted to these changing relations. In the fowler, experience has established a relation between the appearance and flight of a hawk and the destruction of other birds, including game. There is also in him an established relation between those visual impressions answering to a certain distance in space, and the range of his gun. And he has learned, too, what relations of position the sights must bear to a point somewhat in advance of the flying bird, before he can fire with success. Similarly if we go back to the manufacture of the gun. By relations of co-existence between colour, density, and place in the earth, a particular mineral is known as one which yields iron; and the obtainment of iron from it, results when certain correlated acts of ours are adjusted to certain correlated affinities displayed by ironstone, coal, and lime, at a high temperature. If we descend yet a step further, and ask a chemist to explain the explosion of gunpowder, or apply to a mathematician for a theory of projectiles, we still find that special or general relations of co-existence and sequence among properties, motions, spaces, etc., are all they can teach us. And lastly, let it be noted that what we call truth guiding us to successful action and consequent maintenance of life, is simply the accurate correspondence of subjective to objective relations; while error, leading to failure and therefore towards death, is the absence of such accurate correspondence.

If, then, Life, as knowable by us, inclusive of Intelligence in its highest forms, consists in the continuous adjustment of internal relations to external relations, the relative character of our knowledge is necessarily implied. The simplest cognition being the establishment of some connexion between subjective states, answering to some connexion between objective agencies; and each successively more complex cognition being the establishment of some more involved connexion of such states, answering to some more involved connexion of such agencies; it is clear that the process, no matter how far it be carried, can never bring within the reach of Intelligence, either the states themselves or the agencies themselves. Ascertaining which things occur along with which, and what things follow what, supposing it to be pursued exhaustively must still leave us with co-existences and sequences only. If every act of knowing is the formation of a relation in consciousness answering to a relation in the environment, then the relativity of knowledge is self-evident — becomes indeed a truism. Thinking being relationing, no thought can ever express more than relations.

And here let us note how that to which our intelligence is confined, is that with which alone our intelligence is concerned. The knowledge within our reach is the only knowledge that can be of service to us. This maintenance of a correspondence between internal actions and external act ions, merely requires that the agencies acting upon us shall be known in their co-existences and sequences, and not that they shall be known in themselves. If x and y are two uniformly connected properties in some outer object, while a and b are the effects they produce in our consciousness, then the sole need is that a and b and the relation between them, shall always answer to x and y and the relation between them. It matters nothing to us if a and b are like x and y or not. Could they be identical with them, we should not be one whit the better off; and their total dissimilarity is no disadvantage.

Deep down then in the very nature of Life, the relativity of our knowledge is discernible. The analysis of vital actions in general, leads not only to the conclusion that things in themselves cannot be known to us, but also to the conclusion that knowledge of them, were it possible, would be useless.

§26. There remains the final question — What must we say concerning that which transcends knowledge? Are we to rest wholly in the consciousness of phenomena? Is the result of inquiry to exclude utterly from our minds everything but the relative? or must we also believe in something beyond the relative?

The answer of pure logic is held to be that by the limits of our intelligence we are rigorously confined within the relative, and that anything transcending the relative can be thought of as a pure negation, or as a non-existence. "The absolute is conceived merely by a negation of conceivability" writes Sir William Hamilton. "The Absolute and the Infinite," says Mr. Mansel, "are thus, like the Inconceivable and the Imperceptible, names indicating, not an object of thought or of consciousness at all, but the mere absence of the conditions under which consciousness is possible." So that since reason cannot warrant us in affirming the positive existence of that which is cognizable only as a negation, we cannot rationally affirm the positive existence of anything beyond phenomena.

Unavoidable as this conclusion seems, it involves, I think, a grave error. If the premiss be granted the inference must be admitted; but the premiss, in the form presented by Sir William Hamilton and Mr. Mansel, is not strictly true. Though, in the foregoing pages, the arguments used by these writers to show that the Absolute is unknowable, have been approvingly quoted; and though these arguments have been enforced by others equally thoroughgoing; yet there remains to be stated a qualification which saves us from the scepticism otherwise necessitated. It is not to be denied that so long as we confine ourselves to the purely logical aspect of the question, the propositions quoted above must be accepted in their entirety; but when we contemplate its more general, or psychological, aspect, we find that these propositions are imperfect statements of the truth: omitting, or rather excluding, as they do, an all-important fact. To speak specifically: — Besides that definite consciousness of which Logic formulates the laws, there is also an indefinite consciousness which cannot be formulated. Besides complete thoughts, and besides the thoughts which though incomplete admit of completion, there are thoughts which it is impossible to complete; and yet which are still real, in the sense that they are normal affections of the intellect.

Observe, in the first place, that every one of the arguments by which the relativity of our knowledge is demonstrated, distinctly postulates the positive existence of something beyond the relative. To say that we cannot know the Absolute, is, by implication, to affirm that there is an Absolute. In the very denial of our power to learn what the Absolute is, there lies hidden the assumption that it is; and the making of this assumption proves that the Absolute has been present to the mind, not as a nothing but as a something. Similarly with every step in the reasoning by which this doctrine is upheld. The Noumenon, everywhere named as the antithesis to the Phenomenon, is necessarily thought of as an actuality. It is impossible to conceive that our knowledge is a knowledge of Appearances only without at the same time assuming a Reality of which they are appearances; for appearance without reality is unthinkable. Strike out from the argument the terms Unconditioned, Infinite, Absolute, and in place of them write, "negation of conceivability," or "absence of the conditions under which consciousness is possible," and the argument becomes nonsense. To realize in thought any one of the propositions of which the argument consists, the Unconditioned must be represented as positive and not negative. How then can it be a legitimate conclusion from the argument, that our consciousness of it is negative? An argument the very construction of which assigns to a certain term a certain meaning, but which ends in showing that this term has no such meaning, is simply an elaborate suicide. Clearly, then, the very demonstration that a definite consciousness of the Absolute is impossible to us, unavoidably presupposes an indefinite consciousness of it.

Perhaps the best way of showing that we are obliged to form a positive though Vague consciousness of this which transcends distinct consciousness, is to analyze our conception of the antithesis between Relative and Absolute. It is a doctrine called in question by none, that such antinomies of thought as Whole and Part, Equal and Unequal, Singular and Plural, are necessarily conceived as correlatives: the conception of a part is impossible without the conception of a whole; there can be no idea of equality without one of inequality. And it is undeniable that in the same manner, the Relative is itself conceivable as such, only by opposition to the Irrelative or Absolute. Sir William Hamilton, however, in his trenchant (and in most parts unanswerable) criticism on Cousin, contends, in conformity with his position above stated, that one of these correlatives is nothing more than the negation of the other. "Correlatives,' he says, "certainly suggest each other, but correlatives may, or may not, be equally real and positive. In thought contradictories necessarily imply each other, for the knowledge of contradictories is one. But the reality of one contradictory, so far from guaranteeing the reality of the other, is nothing else than its negation. Thus every positive notion (the concept of a thing by what it is) suggests a negative notion (the concept of a thing by what it is not); and the highest positive notion, the notion of the conceivable, is not without its corresponding negative in the notion of the inconceivable. But though these mutually suggest each other, the positive alone is real; the negative is only an abstraction of the other, and in the highest generality, even an abstraction of thought itself." Now the assertion that of such contradictories "the negative is only an abstraction of the other" — "is nothing else than its negation," — is not true. In such correlatives as Equal and Unequal, it is obvious enough that the negative concept contains something besides the negation of the positive one; for the things of which equality is denied are not abolished from consciousness by the denial. And the fact overlooked by Sir William Hamilton is, that the like holds even with those correlatives of which the negative is inconceivable, in the strict sense of the word. Take for example the Limited and the Unlimited. Our notion of the Limited is composed, firstly of a consciousness of some kind of being, and secondly of a consciousness of the limits under which it is known. In the antithetical notion of the Unlimited, the consciousness of limits is abolished, but not the consciousness of some kind of being. It is quite true that in the absence of conceived limits, this consciousness ceases to be a concept properly so called; but it is none the less true that it remains as a mode of consciousness. If, in such cases, the negative contradictory were, as alleged, "nothing else" than the negation of the other, and therefore a mere non-entity then it would follow that negative contradictories could be used interchangeably: the Unlimited might be thought of as antithetical to the Divisible; and the Indivisible as antithetical to the Limited. While the fact that they cannot be so used, proves that in consciousness the Unlimited and the Indivisible are qualitatively distinct, and therefore positive or real; since distinction cannot exist between nothings. The error, (naturally fallen into by philosophers intent on demonstrating the limits and conditions of consciousness,) consists in assuming that consciousness contains nothing but limits and conditions; to the entire neglect of that which is limited and conditioned. It is forgotten that there is something which alike forms the raw material of definite thought and remains after the definiteness which thinking gave it has been destroyed. Now all this applies by change of terms to the last and highest of these antinomies — that between the Relative and the Non-relative. We are conscious of the Relative as existence under conditions and limits. It is impossible that these conditions and limits can be thought of apart from something to which they give the form. The abstraction of these conditions and limits is, by the hypothesis, the abstraction of them only. Consequently there must be a residuary consciousness of something which filled up their outlines. And this indefinite something constitutes our consciousness of the Non-relative or Absolute. Impossible though it is to give to this consciousness any qualitative or quantitative expression whatever, it is not the less certain that it remains with us as a positive and indestructible element of thought.

More manifest still will this truth become when it is observed that our conception of the Relative itself disappears' if our consciousness of the Absolute is a pure negation. It is admitted, or rather it is contended, by the writers I have quoted above, that contradictories can be known only in relation to each other — that equality, for instance, is unthinkable apart from Inequality; and that thus the Relative can itself be conceived only by opposition to the Non-relative. It is also admitted, or rather contended, that the consciousness of a relation implies a consciousness of both the related terms. If we are required to conceive the relation between the Relative and Non-relative without being conscious of both, "we are in fact" (to quote the words of Mr. Mansel differently applied) "required to compare that of which we are conscious with that of which we are not conscious; the comparison itself being an act of consciousness, and only possible through the consciousness of both its objects." What then becomes of the assertion that "the Absolute is conceived merely by a negation of conceivability," or as "the mere absence of the conditions under which consciousness is possible?" If the Non-relative or Absolute, is present in thought only as a mere negation, then the relation between it and the Relative becomes unthinkable, because one of the terms of the relation is absent from consciousness. And if this relation is unthinkable, then is the Relative itself unthinkable, for want of its antithesis: whence results the disappearance of all thought whatever.

Both Sir William Hamilton and Mr. Mansel do, in other places, distinctly imply that our consciousness of the Absolute, indefinite though it is, is positive. The very passage in which Sir William Hamilton asserts that "the absolute is conceived merely by a negation of conceivability," itself ends with the remark that, "by a wonderful revelation we are thus, in the very consciousness of our inability to conceive aught above the relative and finite, inspired with a belief in the existence of something unconditioned beyond the sphere of all comprehensible reality." The last of these assertions practically admits that which the first denies. By the laws of thought as Sir William Hamilton interprets them, he finds himself forced to the conclusion that our consciousness of the Absolute is a pure negation. He nevertheless finds that there does exist in consciousness an irresistible conviction of the real "existence of something unconditioned." And he gets over the inconsistency by speaking of this conviction as "a wonderful revelation," "a belief" with which we are "inspired:" thus apparently hinting that it is supernaturally at variance with the laws of thought. Mr. Mansel is betrayed into a like inconsistency. When he says that "we are compelled, by the constitution of our minds, to believe in the existence of an Absolute and Infinite Being, — a belief which appears forced upon us, as the complement of our consciousness of the relative and the finite;" he clearly says by implication that this consciousness is positive, and not negative. He tacitly admits that we are obliged to regard the Absolute as something more than a negation — that our consciousness of it is not "the mere absence of the conditions under which consciousness is possible."

The supreme importance of this question must be my apology for taxing the reader's attention a little further, in the hope of clearing up the remaining difficulties. The necessarily positive character of our consciousness of the Unconditioned, which, as we have seen, follows from an ultimate law of thought, will be better understood on contemplating the process of thought.

One of the arguments used to prove the relativity of our knowledge, is, that we cannot conceive Space or Time as either limited or unlimited. It is pointed out that when we imagine a limit, there simultaneously arises the consciousness of a space or time beyond the limit. This remoter space or time, though not contemplated as definite, is yet contemplated as real. Though we do not form of it a conception proper, since we do not bring it within bounds, there is yet in our minds the unshaped material of a conception. Similarly with our consciousness of Cause. We are no more able to form a circumscribed idea of Cause, than of Space or Time; and we are consequently obliged to think of the Cause which transcends the limits of our thought as positive though indefinite. As on conceiving any bounded space, there arises a nascent consciousness of space outside the bounds; so, when we think of any definite cause, there arises a nascent consciousness of a cause behind it; and in the one case as in the other, this nascent consciousness is in substance like that which suggests it, though without form. The momentum of thought carries us beyond conditioned existence to unconditioned existence; and this ever persists in us as the body of a thought to which we can give no shape.

Hence our firm belief in objective reality. When we are taught that a piece of matter, regarded by us as existing externally, cannot be really known, but that we can know only certain impressions produced on us, we are yet, by the relativity of thought, compelled to think of these in relation to a cause — the notion of a real existence which generated these impressions becomes nascent. If it be proved that every notion of a real existence which we can frame, is inconsistent with itself — that matter, however conceived by us, cannot be matter as it actually is, our conception, though transfigured, is not destroyed: there remains the sense of reality, dissociated as far as possible from those special forms under which it was before represented in thought. Though Philosophy condemns successively each attempted conception of the Absolute — though in obedience to it we negative, one after another; each idea as it arises; yet, as we cannot expel the entire contents of consciousness, there ever remains behind an element which passes into new shapes. The continual negation of each particular form and limit, simply results in the more or less complete abstraction of all forms and limits; and so ends in an indefinite consciousness of the unformed and unlimited.

And here we come face to face with the ultimate difficulty — How can there be constituted a consciousness of the unformed and unlimited, when, by its very nature, consciousness is possible only under forms and limits? Though not directly withdrawn by the withdrawal of its conditions, must not the raw material of consciousness be withdrawn by implication? Must it not vanish when the conditions of its existence vanish? That there must be a solution of this difficulty is manifest; since even those who would put it do, as already shown, admit that we have some such consciousness; and the solution appears to be that above shadowed forth. Such consciousness is not, and cannot be, constituted by any single act, but is the product of many mental acts. In each concept there is an element which persists. It is impossible for this element to be absent from consciousness, or for it to be present in consciousness alone. Either alternative involves unconsciousness — the one from want of the substance; the other from want of the form. But the persistence of this element under successive conditions, necessitates a sense of it as distinguished from the conditions, and independent of them. The sense of a something that is conditioned in every thought cannot be got rid of, because the something cannot be got rid of. How then must the sense of this something be constituted? Evidently by combining successive concepts deprived of their limits and conditions. We form this indefinite thought, as we form many of our definite thoughts, by the coalescence of a series of thoughts. Let me illustrate this. A large complex object, having attributes too numerous to be represented at once, is yet tolerably well conceived by the union of several representations, each standing for part of its attributes. On thinking of a piano, there first rises in imagination its outer appearance, to which are instantly added (though by separate mental acts) the ideas of its remote side and of its solid substance. A complete conception, however, involves the strings, the hammers, the dampers, the pedals; and while successively adding these, the attributes first thought of lapse partially or wholly out of consciousness. Nevertheless, the whole group constitutes a representation of the piano. Now as in this case we form a definite concept of a special existence, by imposing limits and conditions in successive acts; so, in the converse case, by taking away limits and conditions in successive acts, we form an indefinite notion of general existence. By fusing a series of states of consciousness, from each of which, as it arises, the limitations and conditions are abolished, there is produced a consciousness of something unconditioned. To speak more rigorously: — this consciousness is not the abstract of any one group of thoughts, ideas, or conceptions; but it is the abstract of all thoughts, ideas, or conceptions. That which is common to them all we predicate by the word existence. Dissociated as this becomes from each of its modes by the perpetual change of those modes, it remains as an indefinite consciousness of something constant under all modes — of being apart from its appearances. The distinction we feel between specialized existences and general existence, is the distinction between that which is changeable in us and that which is unchangeable. The contrast between the Absolute and the Relative in our minds, is really the contrast between that mental element which exists absolutely, and those which exist relatively.

So that this ultimate mental element is at once necessarily indefinite and necessarily indestructible. Our consciousness of the unconditioned being literally the unconditioned consciousness, or raw material of thought to which in thinking we give definite forms, it follows that an ever-present sense of real existence is the basis of our intelligence. As we can in successive mental acts get rid of all particular conditions and replace them by others, but cannot get rid of that undifferentiated substance of consciousness which is conditioned anew in every thought, there ever remains with us a sense of that which exists persistently and independently of conditions. While by the laws of thought we are prevented from forming a conception of absolute existence; we are by the laws of thought prevented from excluding the consciousness of absolute existence: this consciousness being, as we here see, the obverse of self-consciousness. And since the measure of relative validity among our beliefs, is the degree of their persistence in opposition to the efforts made to change them, it follows that this which persists at all times, under all circumstances, has the highest validity of any.

The points in this somewhat too elaborate argument are these: In the very assertion that all knowledge, properly so called, is Relative, there is involved the assertion that there exists a Non-relative. In each step of the argument by which this doctrine is established, the same assumption is made. From the necessity of thinking in relations, it follows that the Relative is itself inconceivable, except as related to a real Non-relative. Unless a real Non-relative or Absolute be postulated, the Relative itself becomes absolute, and so brings the argument to a contradiction. And on watching our thoughts we have seen how impossible it is to get rid of the consciousness of an Actuality lying behind Appearances; and how from this impossibility, results our indestructible belief in that Actuality.

Chapter 5

The Reconcilation

§27. Thus do all lines of argument converge to the same conclusion. Those imbecilities of the understanding which disclose themselves when we try to answer the highest questions of objective science, subjective science proves to be necessitated by the laws of that understanding. Finally we discover that this conclusion which, in its unqualified form, seems opposed to the instinctive convictions of mankind, falls into harmony with them when the missing qualification is supplied. Here, then, is that basis of agreement we set out to seek. This conclusion which objective science illustrates and subjective science shows to be unavoidable, — this conclusion which brings the results of speculation into harmony with those of common sense; is also the conclusion which reconciles Religion with Science. Common Sense asserts the existence of a reality; Objective Science proves that this reality cannot be what we think it; Subjective Science shows why we cannot think of it as it is, and yet are compelled to think of it as existing; and in this assertion of a Reality utterly inscrutable in nature, Religion finds an assertion essentially coinciding with her own. We are obliged to regard every phenomenon as a manifestation of some Power by which we are acted upon; though omnipresence is unthinkable, yet, as experience discloses no bounds to the diffusion of phenomena, we are unable to think of limits to the presence of this Power; while the criticisms of Science teach us that this Power is Incomprehensible. And this consciousness of an Incomprehensible Power, called omnipresent from inability to assign its limits, is just that consciousness on which Religion dwells.

To understand fully how real is the reconciliation thus reached, it will be needful to look at the respective attitudes that Religion and Science have all along maintained towards this conclusion.

§28. In its earliest and crudest forms Religion manifested, however vaguely and inconsistently, an intuition forming the germ of this highest belief in which philosophies finally unite. The consciousness of a mystery is traceable in the rudest ghost-theory. Each higher creed, rejecting those definite and simple interpretations of Nature previously given, has become more religious by doing this. As the concrete and conceivable agencies assigned as the causes of things, have been replaced by agencies less concrete and conceivable, the element of mystery has necessary become more predominant. Through all its phases the disappearance of those dogmas by which the mystery was made unmysterious, has formed the essential change delineated in religious history. And so Religion has been approaching towards that complete recognition of this mystery which is its goal.

For its essentially valid belief Religion has constantly done battle. Gross as were the disguises under which it first espoused this belief, and cherishing this belief, even still, under disfiguring vestments, it has never ceased to maintain and defend it. Though from age to age Science has continually defeated it wherever they have come in collision, and has obliged it to relinquish one or more of its positions, it has held the remaining ones with undiminished tenacity. After criticism has abolished its arguments, there has still remained with it the indestructible consciousness of a truth which, however faulty the mode in which it had been expressed, is yet a truth beyond cavil.

But while from the beginning, Religion has had the all-essential office of preventing men from being wholly absorbed in the relative or immediate, and of awakening them to a consciousness of something beyond it, this office has been but very imperfectly discharged. In its early stages the consciousness of supernature being simply the consciousness of numerous supernatural persons essentially man-like, was not far removed from the ordinary consciousness. As thus constituted, Religion was and has ever been more or less irreligious; and indeed continues to be largely irreligious even now. In the first place (restricting ourselves to Religion in its more developed form), it has all along professed to have some knowledge of that which transcends knowledge, and has so contradicted its own teachings. While with one breath it has asserted that the Cause of all things passes understanding, it has, with the next breath, asserted that the Cause of all things possesses such or such attributes — can be in so far understood. In the second place, while in great part sincere in its fealty to the great truth it has had to uphold, it has often been insincere, and consequently irreligious, in maintaining the untenable doctrines by which it has obscured this great truth. Each assertion respecting the nature, acts, or motives of that Power which the Universe manifests to us, has been repeatedly called in question, and proved to be inconsistent with itself, or with accompanying assertions. Yet each of them has been age after age insisted on. Just as though unaware that its central position was impregnable, Religion has obstinately held every outpost long after it was obviously indefensible. And this introduces us to the third and most serious form of irreligion which Religion has displayed; namely, an imperfect belief in that which it especially professes to believe. How truly its central position is impregnable, Religion has never adequately realized. In the devoutest faith as we commonly see it, there lies hidden a core of scepticism; and it is this scepticism which causes that dread of inquiry shown by Religion when face to face with Science. Obliged to abandon one by one the superstitions it once tenaciously held, and daily finding other cherished beliefs more and more shaken, Religion secretly fears that all things may some day be explained; and thus itself betrays a lurking doubt whether that Incomprehensible Cause of which it is conscious, is really incomprehensible.

Of Religion then, we must always remember, that amid its many errors and corruptions it has asserted and diffused a supreme verity. From the first, the recognition of this supreme verity, in however imperfect a manner, has been its vital element; and its chief defects, once extreme but gradually diminishing, have been its failures to recognize in full that which it recognized in part. The truly religious element of Religion has always been good; that which has proved untenable in doctrine and vicious in practice, has been its irreligious element; and from this it has been undergoing purification.

§29. And now observe that the agent which has effected the purification has been Science. On both sides this fact is overlooked. Religion ignores its immense debt to Science; and Science is scarcely at all conscious how much Religion owes it. Yet it is demonstrable that every step by which Religion has progressed from its first low conception to the comparatively high one now reached, Science has helped it, or rather forced it, to take; and that even now, Science is urging further steps in the same direction.

When we include under the name Science all definite knowledge of the order existing among phenomena, it becomes manifest that from the outset, the discovery of an established order has modified that conception of disorder or undetermined order, which underlies every superstition. As fast as experience proves that certain familiar changes always present the same sequences, there begins to fade from the mind the conception of special personalities to whose variable wills they were before ascribed. And when, step by step, accumulating observations do the like with the less familiar changes, a similar modification of belief takes place respecting them.

While this process seems to those who effect it, and those who undergo it, an anti-religious one, it is really the reverse. Instead of the specific comprehensible agency before assigned, there is substituted a less specific and less comprehensible agency; and though this, standing in opposition to the previous one, cannot at first call forth the same feeling, yet, as being less comprehensible, it must eventually call forth this feeling more fully. Take an instance. Of old the Sun was regarded as the chariot of a god, drawn by horses. How far the idea thus grossly expressed was idealized, we need not inquire. It suffices to remark that this accounting for the apparent motion of the Sun by an agency like certain visible terrestrial agencies, reduced a daily wonder to the level of the commonest intellect. When, many centuries after, Copernicus having enunciated the heliocentric theory of the solar system, Kepler discovered that the orbits of the planets are ellipses, and that the planets describe equal areas in equal times, he concluded that in each of them there must exist a spirit to guide its movements. Here we see that with the progress of Science, there had disappeared the idea of a gross mechanical traction, such as was first assigned in the case of the Sun; but that while for the celestial motions there was substituted a less-easily conceivable force, it was still thought needful to assume personal agents as causes of the regular irregularity of the motions. When, finally it was proved that these planetary revolutions with all their variations and disturbances, conform to one universal law — when the presiding spirits which Kepler conceived were set aside, and the force of gravitation put in their places; the change was really the abolition of an imaginable agency, and the substitution of an unimaginable one. For though the law of gravitation is within our mental grasp, it is impossible to realize in thought the force of gravitation. Newton himself confessed the force of gravitation to be incomprehensible without the intermediation of an ether; and, as we have already seen, (§18), the assumption of an ether does not help us. Thus it is with Science in general. Its progress in grouping particular relations of phenomena under laws, and these special laws under laws more and more general, is of necessity a progress to causes more and more abstract. And causes more and more abstract, are of necessity causes less and less conceivable; since the formation of an abstract conception involves the dropping of certain concrete elements of thought. Hence the most abstract conception, to which Science is slowly approaching, is one that merges into the inconceivable or unthinkable, by the dropping of all concrete elements of thought. And so is justified the assertion that the beliefs which Science has forced upon Religion, have been intrinsically more religious than those which they supplanted.

Science, however, like Religion, has but very incompletely fulfilled its office. As Religion has fallen short of its function in so far as it has been irreligious; so has Science fallen short of its function in so far as it has been unscientific. Let us note the several parallelisms. In its earlier stages Science, while it began to teach the constant relations of phenomena, and thus discredited the belief in separate personalities as the causes of them, itself substituted the belief in casual agencies which, if not personal, were yet concrete. When certain facts were said to show "Nature's abhorrence of a vacuum," when the properties of gold were explained as due to some entity called "aureity," and when the phenomena of life were attributed to "a vital principle;" there was set up a mode of interpreting the facts which, while antagonistic to the religious mode, because assigning other agencies, was also unscientific, because it assumed a knowledge of that about which nothing was known. Having abandoned these metaphysical agencies — having seen that they are not independent existences, but merely special combinations of general causes, Science has more recently ascribed extensive groups of phenomena to electricity, chemical affinity, and other like general powers. But in speaking of these as ultimate and independent entities, Science has preserved substantially the same attitude as before. Accounting thus for all phenomena, it has not only maintained its seeming antagonism to Religion, by alleging agencies of a radically unlike kind; but, in so far as it has tacitly implied its comprehension of these agencies, it has continued unscientific. At the present time, however, the most advanced men of science are abandoning these later conceptions, as their predecessors abandoned the earlier ones. Magnetism, heat, light, etc., which were early in the century spoken of as so many distinct imponderables, physicists now regard as different modes of manifestation of some one universal force; and in so regarding them are ceasing to think of this force as comprehensible. In each phase of its progress, Science has thus stopped short with superficial solutions — has unscientifically neglected to ask what were the natures of the agents it familiarly invoked. Though in each succeeding phase it has gone a little deeper, and merged its supposed agents in more general and abstract ones, it has still, as before, rested content with these aS if they were ascertained realities. And this, which has all along been an unscientific characteristic of Science, has all along been a part-cause of its conflict with Religion.

§30. Thus from the outset the faults of both Religion and Science have been the faults of imperfect development. Originally a mere rudiment, each has been growing more complete; the vice of each has in all times been its incompleteness; the disagreements between them have been consequences of their incompleteness; and as they reach their final forms they come into harmony.

The progress of intelligence has throughout been dual. Though it has not seemed so to those who made it, every step in advance has been a step towards both the natural and the supernatural. The better interpretation of each phenomenon has been, on the one hand, the rejection of a cause that was relatively conceivable in its nature but unknown in the order of its actions, and, on the other hand, the adoption of a cause that was known in the order of its actions but relatively inconceivable in its nature. The first advance involved the conception of agencies less assimilable to the familiar agencies of men and animals, and therefore less understood; while, at the same time, such newly-conceived agencies, in so far as they were distinguished by their uniform effects, were better understood than those they replaced. All subsequent advances display the same result; and thus the progress has been as much towards the establishment of a positively unknown as towards the establishment of a positively known. Though as knowledge advances, unaccountable and seemingly supernatural facts are brought into the category of facts that are accountable or natural; yet, at the same time, all accountable or natural facts are proved to be in their ultimate genesis unaccountable and supernatural. And so there arise two antithetical states of mind, answering to the opposite sides of that existence about which we think. While our consciousness of Nature under the one aspect constitutes Science, our consciousness of it under the other aspect constitutes Religion.

In other words, Religion and Science have been undergoing a slow differentiation, and their conflicts have been due to the imperfect separation of their spheres and functions. Religion has, from the first, struggled to unite more or less science with its nescience; Science has, from the first, kept hold of more or less nescience as though it were a part of science. So long as the process of differentiation is incomplete, more or less of antagonism must continue. Gradually as the limits of possible cognition are established, the causes of conflict will diminish. And a permanent peace will be reached when Science becomes fully convinced that its explanations are proximate and relative, while Religion becomes fully convinced that the mystery it contemplates is ultimate and absolute.

Religion and Science are therefore necessary correlatives. To carry further a metaphor before used,they are the positive and negative poles of thought; of which neither can gain in intensity without increasing the intensity of the other.

§31. Some do indeed allege that though the Ultimate Cause of things cannot really be conceived by us as having specified attributes, it is yet incumbent upon us to assert those attributes. Though the forms of our consciousness are such that the Absolute cannot in any manner or degree be brought within them, we are nevertheless told that we must represent the Absolute to ourselves as having certain characters. As writes Mr. Mansel, in the work from which I have already quoted largely — "It is our duty, then, to think of God as personal; and it is our duty to believe that He is infinite."

Now if there be any meaning in the foregoing arguments, duty requires us neither to affirm nor deny personality. Our duty is to submit ourselves to the established limits of our intelligence, and not perversely to rebel against them. Let those who can, believe that there is eternal war set between our intellectual faculties and our moral obligations. I, for one, admit no such radical vice in the constitution of things.

This which to most will seem an essentially irreligious position, is an essentially religious one — nay is the religious one, to which, as already shown, all others are but approximations. In the estimate it implies of the Ultimate Cause, it does not fall short of the alternative position, but exceeds it. Those who espouse this alternative position, assume that the choice is between personality and something lower than personality; whereas the choice is rather between personality and something that may be higher. Is it not possible that there is a mode of being as much transcending Intelligence and Will, as these transcend mechanical motion? Doubtless we are totally unable to imagine any such higher mode of being. But this is not a reason for questioning its existence; it is rather the reverse. Have we not seen how utterly unable our minds are to form even an approach to a conception of that which underlies all phenomena? Is it not proved that we fail because of the incompetency of the Conditioned to grasp the Unconditioned ? Does it not follow that the Ultimate Cause cannot in any respect be conceived because it is in every respect greater than can be conceived? And may we not therefore rightly refrain from assigning to it any attributes whatever, on the ground that such attributes, derived as they must be from our own natures, are not elevations but degradations? Indeed it seems strange that men should Suppose the highest worship to lie in assimilating the object of their worship to themselves. Not in asserting a transcendent difference, but in asserting a certain likeness, consists the element of their creed which they think essential. It is true that from the time when the rudest savages imagined the causes of things to be persons like themselves but invisible, down to our own time, the degree of assumed likeness has been diminishing. But though a bodily form and substance similar to that of man, has long since ceased, among cultivated races, to be a literally-conceived attribute of the Ultimate Cause — though the grosser human desires have been also rejected as unfit elements of the conception — though there is some hesitation in ascribing even the higher human feelings, save in idealized shapes; yet it is still thought not only proper, but imperative, to ascribe the most abstract qualities of our nature. To think of the Creative Power as in all respects anthropomorphous, is now considered impious by men who yet hold themselves bound to think of the Creative. Power as in some respects anthropomorphous; and who do not see that the one proceeding is but an evanescent form of the other. And then, most marvellous of all, this course is persisted in even by those who contend that we are wholly unable to frame any conception whatever of the Creative Power. After it has been shown that every supposition respecting the genesis of the Universe commits us to alternative impossibilities of thought — after it has been shown why by the very constitution of our minds, we are debarred from thinking of the Absolute; it is still asserted that we ought to think of the Absolute thus and thus. In all ways we find thrust on us the truth, that we are not permitted to know — nay are not even permitted to conceive that Reality which is behind the veil of Appearance; and yet it is said to be our duty to believe (and in so far to conceive) that this Reality exists in a certain defined manner. Shall we call this reverence? or shall we call it the reverse?

Volumes might be written upon the impiety of the pious. Through the printed and spoken thoughts of religious teachers, may everywhere be traced a professed familiarity with the ultimate mystery of things, which, to say the least of it, is anything but congruous with the accompanying expressions of humility. The attitude thus assumed can be fitly represented only by further developing a simile long current in theological controversies — the simile of the watch. If for a moment we made the grotesque supposition that the tickings and other movements of a watch constituted a kind of consciousness; and that a watch possessed of such a consciousness, insisted on regarding the watchmaker's actions as determined like its own by springs and escapements; we should simply complete a parallel of which religious teachers think much. And were we to suppose that a watch not only formulated the cause of its existence in these mechanical terms, but held that watches were bound out of reverence so to formulate this cause, and even vituperated, as atheistic watches, any that did not venture so to formulate it; we should merely illustrate the presumption of theologians by carrying their own argument a step further. A few extracts will bring home to the reader the justice of this comparison. We are told, for example, by one of high repute among religious thinkers that the Universe is "the manifestation and abode of a Free Mind, like our own; embodying His personal thought in its adjustments, realizing His own ideal in its phenomena, just as we express our inner faculty and character through the natural language of an external life. In this view, we interpret Nature by Humanity; we find the key to her aspects in such purposes and affections as our own consciousness enables us to conceive; we look everywhere for physical signals of an ever-living Will; and decipher the universe as the autobiography of an Infinite Spirit, repeating itself in miniature within our Finite Spirit." The same writer goes still further. He not only thus parallels the assimilation of the watchmaker to the watch, — he not only thinks the created can "decipher" "the autobiography" of the Creating; but he asserts that the necessary limits to the one are necessary limits to the other. The primary qualities of bodies, he says, "belong eternally to the material datum objective to God" and control his acts; while the secondary ones are "products of pure Inventive Reason and Determining Will" — constitute "the realm of Divine originality." * * "While on this Secondary field His Mind and ours are thus contrasted, they meet in resemblance again upon the Primary; for the evolutions of deductive Reason there is but one track possible to all intelligences; no merum arbitrium can interchange the false and true, or make more than one geometry, one scheme of pure Physics, for all worlds; and the Omnipotent Architect Himself, in realizing the Kosmical conception, in shaping the orbits out of immensity and determining seasons out of eternity, could but follow the laws of curvature, measure and proportion." That is to say the Ultimate Cause is like a human mechanic, not only as "shaping" the "material datum objective to" Him, but also as being obliged to conform to the necessary properties of that datum. Nor is this all. There follows some account of "the Divine psychology," to the extent of saying that "we learn" "the character of God — the order of affections in Him" from "the distribution of authority in the hierarchy of our impulses." In other words, it is alleged that the Ultimate Cause has desires that are to be classed as higher and lower like our own.* Every one has heard of the king who wished he had been present at the creation of the world, that he might have given good advice. He was humble, however, compared with those who profess to understand not only the relation of the Creating to the created, but also how the Creating is constituted. And yet this transcendent audacity, which thinks to penetrate the secrets of the Power manifested through all existence — nay, even to stand behind that Power and note the conditions to its action — this it is which passes current as piety! May we not affirm that a sincere recognition of the truth that our own and all other existence is a mystery absolutely beyond our comprehension, contains more of true religion than all the dogmatic theology ever written?

<* These extracts are from an article entitled " Nature and God," published in the National Review for October, 1860, by Dr. Martineau.>

Meanwhile let us recognize whatever of permanent good there is in these persistent attempts to frame conceptions of that which cannot be conceived. From the beginning it has been only through the successive failures of such conceptions to satisfy the mind, that higher and higher ones have been gradually reached; and doubtless, the conceptions now current are indispensable as transitional modes of thought. Even more than this may be willingly conceded. It is possible, nay probable, that under their most abstract forms, ideas of this order will always continue to occupy the background of our consciousness. Very likely there will ever remain a need to give a shape to that indefinite sense of an Ultimate Existence, which forms the basis of our intelligence. We shall always be under the necessity of contemplating it as some mode of being; that is — of representing it to ourselves in some form of thought, however vague. And we shall not err in doing this so long as we treat every notion we thus frame as merely a symbol. Perhaps the constant formation of such symbols and constant rejection of them as inadequate, may be hereafter, as it has hitherto been, a means of discipline. Perpetually to construct ideas requiring the utmost stretch of our faculties, and perpetually to find that such ideas must be abandoned as futile imaginations, may realize to us more fully than any other course, the greatness of that which we vainly strive to grasp. By continually seeking to know and being continually thrown back with a deepened conviction of the impossibility of knowing, we may keep alive the consciousness that it is alike our highest wisdom and our highest duty to regard that through which all things exist as The Unknowable.

§32. An immense majority will refuse, with more or less of indignation, a belief seeming to them so shadowy and indefinite. "You offer us," they will say, "an unthinkable abstraction in place of a Being towards whom we may entertain definite feelings. Though we are told that the Absolute is the only reality, yet since we are not allowed to conceive it, it might as well be a pure negation. Instead of a Power which we can regard as having some sympathy with us, you would have us contemplate a Power to which no emotion whatever can be ascribed. And so we are to be deprived of the very substance of our faith." This kind of protest of necessity accompanies every change from a lower creed to a higher. The belief in a community of nature between himself and the object of his worship, has always been to Man a satisfactory one; and he has always accepted with reluctance those successively less concrete conceptions which have been forced upon him. Doubtless, in all times and places, it has consoled the barbarian to think of his deities as like himself in nature, that they might be bribed by offerings of food; and the assurance that deities could not be so propitiated must have been repugnant, because it deprived him of an easy method of gaining supernatural protection. To the Greeks it was manifestly a source of comfort that on occasions of difficulty they could obtain, through oracles, the advice of their gods, — nay might even get the personal aid of their gods in battle; and it was probably a very genuine anger which they visited upon philosophers who called in question these gross ideas of their mythology. A religion which teaches the Hindoo that is is impossible to purchase eternal happiness by placing himself under the wheel of Juggernaut, can scarcely fail to seem a cruel one to him; since it deprives him of the pleasurable consciousness that he can at will exchange miseries for joys. Nor is it less clear that to our Catholic ancestors, the beliefs that crimes could be compounded for by the building of churches, that their own punishments and those of their relatives could be abridged by the saying of masses, and that divine aid or forgiveness might be gained through the intercession of saints, were highly solacing ones; and that Protestantism, in substituting the conception of a God so comparatively unlike themselves as not to be influenced by such methods, must have appeared hard and cold. Naturally therefore, we must expect a further step in the same direction to meet with a similar resistance from outraged sentiments. No mental revolution can be accomplished without more or less laceration. Be it a change of habit or a change of conviction, it must, if the habit or conviction be strong, do violence to some of the feelings; and these must of course oppose it. For long-experienced, and therefore definite, sources of satisfaction, have to be substituted sources of satisfaction that have not been experienced, and are therefore indefinite. That which is relatively well known and real, has to be given up for that which is relatively unknown and ideal. And of course such an exchange cannot be made without a conflict involving pain. Especially, then, must there arise a strong antagonism to any alteration in so deep and vital a conception as that with which we are here dealing. Underlying, as this conception does, all ideas conceding the established order of things, a modification of it threatens to reduce the superstructure to ruins. Or to change the metaphor — being the root with which are connected our ideas of goodness, rectitude, or duty, it appears impossible that it should be transformed without causing these to wither away and die. The whole higher part of the nature takes up arms against a change which seems to eradicate morality.

This is by no means all that has to be said for such protests. There is a deeper meaning in them. They do not simply express the natural repugnance to a revolution of belief, here made specially intense by the vital importance of the belief to be revolutionized; but they also express an instinctive adhesion to a belief that is in one sense the best — the best for those who thus cling to it, though not abstractedly the best. For here it is to be remarked that what were above spoken of as the imperfections of Religion, at first great but gradually diminishing, have been imperfections as measured by an absolute standard, and not as measured by a relative one. Speaking generally, the religion current in each age and among each people, has been as near an approximation to the truth as it was then and there possible for men to receive. The concrete forms in which it has embodied the truth, have been the means of making thinkable what would otherwise have been unthinkable; and so have for the time being served to increase its impressiveness. If we consider the conditions of the case, we shall find this to be an unavoidable conclusion. During each stage of progress men must think in such terms of thought as they possess. While all the conspicuous changes of which they can observe the origins, have men and animals as antecedents, they are unable to think of antecedents in general under any other shapes; and hence creative agencies are almost of necessity conceived by them in these shapes. If, during this phase, these concrete conceptions were taken from them, and the attempt made to give them comparatively abstract conceptions, the result would be to leave their minds with none at all; since the substituted ones could not be mentally represented. Similarly with every successive stage of religious belief, down to the last. Though, as accumulating experiences slowly modify the earliest ideas of causal personalities, there grow up more general and vague ideas of them; yet these cannot be at once replaced by others still more general and vague. Further experiences must supply the needful further abstractions, before the mental void left by the destruction of such inferior ideas can be filled by ideas of a superior order. And at the present time, the refusal to abandon a relatively concrete consciousness for a relatively abstract one, implies the inability to frame the relatively abstract one; and so implies that the change would be premature and injurious. Still more clearly shall we see the injuriousness of any such premature change, on observing that the effects of a belief upon conduct must be diminished in proportion as the vividness with which it is realized becomes less. Evils and benefits akin to those which the savage has personally felt, or learned from those who have felt them, are the only evils and benefits he can understand; and these must be looked for as coming in ways like those of which he has had experience. His deities must be imagined to have like motives and passions and methods with the beings around him; for motives and passions and methods of a higher character being unknown to him, and in great measure unthinkable by him, cannot be so represented in thought as to influence his deeds. During every phase of civilization, the actions of the Unseen Reality, as well as the resulting rewards and punishments, being conceivable only in such forms as experience furnishes, to supplant them by higher ones be fore wider experiences have made higher ones conceivable, is to set up vague and uninfluential motives for definite and influential ones. Even now for the great mass of men, unable to trace out with clearness those good and bad consequences which conduct brings round through the established order of things, it is well that there should be depicted future punishments and future joys — pains and pleasures of definite kinds, produced in ways direct and simple enough to be clearly imagined. Nay still more must be conceded. Few are as yet wholly fitted to dispense with such conceptions as are current. The highest abstractions take so great a mental power to realize with any vividness, and are so inoperative on conduct unless they are vividly realized, that their regulative effects must for a long period to come be appreciable on but a small minority. To see clearly how a right or wrong act generates consequences, internal and external, that go on branching out more widely as years progress, requires a rare power of analysis. And to estimate these consequences in their totality requires a grasp of thought possessed by none. Were it not that throughout the progress of the race, men's experiences of the effects of conduct have been slowly generalized into principles — were it not that these principles have been from generation to generation insisted on by parents, upheld by public opinion, sanctified by religion, and enforced by threats of eternal damnation for disobedience — were it not that under these potent influences habits have been modified, and the feelings proper to them made innate; disastrous results would follow the removal of those strong and distinct motives which the current belief supplies. Even as it is, those who relinquish the faith in which they have been brought up, for this most abstract faith in which Science and Religion unite, may not uncommonly fail to act up to their convictions. Left to their organic morality, enforced only by general reasonings difficult to keep before the mind, their defects of nature will often come out more strongly than they would have done under their previous creed. The substituted creed can become adequately operative only when it becomes, like the present one, an element in early education, and has the support of a strong social sanction. Nor will men be quite ready for it until, through the continuance of a discipline which has partially moulded them to the conditions of social existence, they are completely moulded to those conditions.

We must therefore recognize the resistance of a change of theological opinion, as in great measure salutary. Forms of religion, like forms of government, must be fit for those who live under them; and in the one case as in the other, the form which is fittest is that for which there is an instinctive preference. As a barbarous race needs a harsh terrestrial rule, and shows attachment to a despotism capable of the necessary rigour; so does such a race need a belief in a celestial rule that is similarly harsh, and shows attachment to such a belief. And as the sudden substitution of free institutions for despotic ones, is sure to be followed by a reaction; so, if a creed full of dreadful ideal penalties is all at once replaced by one presenting ideal penalties that are comparatively gentle, there will inevitably be a return to some modification of the old belief. The parallelism holds yet further. During those early stages in which there is extreme incongruity between the relatively best and the absolutely best, both political and religious changes, when at rare intervals they occur, are violent; and they entail violent retrogressions. But as the incongruity between that which is and that which should be, diminishes, the changes become more moderate, and are succeeded by more moderate counter-movements; until, as these movements and counter-movements decrease in amount and increase in frequency, they merge into an almost continuous growth. This holds true of religious creeds and forms, as of civil ones. And so we learn that theological conservatism, like political conservatism, has an important function.

§33. That spirit of toleration which is so marked a trait of modern times, has thus a deeper meaning than is supposed. What we commonly regard simply as a due respect for the right of private judgment, is really a necessary condition to the balancing of the progressive and conservative tendencies — is a means of maintaining the adaptation between men's beliefs and their natures. It is therefore a spirit to be fostered; and especially by the catholic thinker, who perceives the functions of these conflicting creeds. Doubtless whoever feels the greatness of the error his fellows cling to and the greatness of the truth they reject, will find it hard to show a due patience. It is hard to listen calmly to the futile arguments used in support of irrational doctrines, and to the misrepresentations of antagonist doctrines. It is hard to bear the display of that pride of ignorance which so far exceeds the pride of science. Naturally such a one will be indignant when charged with irreligion because he declines to accept the carpenter-theory of creation as the most worthy one. He may think it needless, as it is difficult, to conceal his repugnance to a creed which tacitly ascribes to The Unknowable a love of adulation such as would be despised in a human being. Convinced as he is that pain, as we see it in the order of nature, is an aid to the average welfare, there will perhaps escape from him an angry condemnation of the belief that punishment is a divine vengeance, and that divine vengeance is eternal. He may be tempted to show his contempt when he is told that actions instigated by an unselfish sympathy or by a pure love of rectitude, are intrinsically sinful; and that conduct is truly good only when it is due to a faith whose openly-professed motive is other-worldliness. But he must restrain such feelings. Though he may be unable to do this during the excitement of controversy, he must yet qualify his antagonism in calmer moments; so that his mature judgment and resulting conduct may be without bias.

To this end let him bear in mind three cardinal facts — two of them already dwelt on, and one still to be pointed out. The first is that with which we commenced; namely, the existence of a fundamental verity under all forms of religion, however degraded. In each of them there is a soul of truth. The second, set forth at length in the foregoing section, is that while those concrete elements in which each creed embodies this soul of truth, are bad as measured by an absolute standard, they are good as measured by a relative standard. The remaining one is that these various beliefs are parts of the constituted order of things, and, if not in their special forms yet in their general forms, necessary parts. Seeing how one or other of them is everywhere present, is of perennial growth, and when cut down redevelops in a form but slightly modified, we cannot avoid the inference that they are needful accompaniments of human life, severally fitted to the societies in which they are indigenous. We must recognize them as elements in that great evolution of which the beginning and end are beyond our knowledge or conception — as modes of manifestation of The Unknowable, and as having this for their warrant.

Our toleration therefore should be the widest possible. In dealing with alien beliefs our endeavour must be, not simply to refrain from injustice of word or deed, but also to do justice by an open recognition of positive worth. We must qualify our disagreement with as much as may be of sympathy.

§34. These admissions will perhaps be held to imply that the current theology should be passively accepted, or, at any rate, should not be actively opposed. "Why," it may be asked, "if creeds are severally fit for their times and places, should we not rest content with that to which we are born? If the established belief contains an essential truth — if the forms under which it presents this truth, though intrinsically bad, are extrinsically good — if the abolition of these forms would be at present detrimental to the great majority — nay, if there are scarcely any to whom the ultimate and most abstract belief can furnish an adequate rule of life; surely it is wrong, for the present at least, to propagate this ultimate and most abstract belief."

The reply is that though existing religious ideas and institutions have an average adaptation to the characters of the people who live under them, yet, as these characters are ever changing, the adaptation is ever becoming imperfect. and the ideas and institutions need remodelling with a frequency proportionate to the rapidity of the change. Hence, while it is requisite that free play should be given to conservative thought and action, progressive thought and action must also have free play. Without the agency of both there cannot be those continual re-adaptations which orderly progress demands.

Whoever hesitates to utter that which he thinks the highest truth, lest it should be too much in advance of the time, may reassure himself by looking at his acts from an impersonal point of view. Let him remember that opinion is the agency through which character adapts external arrangements to itself, and that his option rightly forms part of this agency — is a unit of force constituting with other such units, the general power which works out social changes; and he will perceive that he may properly give utterance to his innermost conviction: leaving it to produce what effect it may. It is not for nothing that he has in him these sympathies with some principles and repugnance to others. He, with all his capacities, and aspirations, and beliefs, is not an accident but a product of the time. While he is a descendant of the past he is a parent of the future; and his thoughts are as children born to him, which he may not carelessly let die. Like every other man he may properly consider himself as one of the myriad agencies through whom works the Unknown Cause; and when the Unknown Cause produces in him a certain belief, he is thereby authorized to profess and act out that belief. For, to render in their highest sense the words of the poet —

Nature is made better by no mean,
But nature makes that mean: over that art
Which you say adds to nature, is an art
That nature makes.

Not as adventitious therefore will the wise man regard the faith which is in him. The highest truth he sees he will fearlessly utter: knowing that, let what may come of it, he is thus playing his right part in the world — knowing that if he can effect the change he aims at — well; if not — well also; though not so well.

Postscript to Part I

OF multitudinous criticisms made on the preceding five chapters since the publication of First Principles in 1862, it is practicable to notice only those of chief importance. Even to do this would be impracticable were it not that most of them are essentially the same and may be met by the same answers.

Several opponents have contended that it is illegitimate to assert of the Ultimate Reality lying behind Appearance, that it is unknown and unknowable. The statement that it is unknowable is said to assume knowledge greater than we can have: alike as putting an arbitrary limit to possible human faculty and as asserting something concerning that of which we are said to know nothing: a contradiction.

To the first of these objections, that an arbitrary limit is put to possible human faculty an answer has already been given in §24, where it has been shown that knowledge involves the three elements, Relation, Difference, Likeness; and that unconditioned existence, of which no one of these can be affirmed without contradiction, consequently does not present a subject-matter for knowledge. Further, in the next section it was pointed out that in the process of knowing there is the same implication. Thinking being relationing, no thought can express more than relations. From which truth it is inferable that human faculty must become fundamentally unlike what it is, and knowledge must become something other than what we call knowledge, before anything can be known about the Unconditioned.

The second objection is not thus easily met. It is doubtless true that saying what a thing is not, is, in some measure, saying what it is; since if, of all possible assertions respecting it, one is cancelled, the cancelling, by diminishing the number of possible assertions, implies an incipient definition. A series of statements of what it is not, excluding one possibility after another, becomes eventually a line of exclusions drawn round it — a definition of it. The game of Twenty Questions illustrates this. Hence it cannot be denied that to affirm of the Ultimate Reality that it is unknowable is, in a remote way, to assert some knowledge of it, and therefore involves a contradiction.

This extreme case, however, does but serve to bring out the truth that, limited as our intelligence is to the relative, and obliged as we are to use words which have been moulded to it, we cannot say anything concerning the non-relative without carrying into our propositions meanings connoted by those words — meanings foreign to a subject-matter which transcends relations. Intellect being framed simply by and for converse with phenomena, involves us in nonsense when we try to use it for anything beyond phenomena. This inability of the thinking faculty in presence of the Unconditioned, is shown not only by the self-contradictory nature of its product, but also by the arrest of its process before completion. In attempting to pass the limit it breaks down before it has finished its first step. For since every thought expresses a relation — since thinking is relationing — thinking ceases when one of the two terms of a relation remains blank. As the relation is incomplete there is no thought properly so called: thought fails. So that we cannot rightly conceive even a connexion between noumenon and phenomenon. We are unable in any consistent way to assert a Reality standing in some relation to the Apparent. Such a relation is not truly imaginable.

And yet by the very nature of our intelligence we are compelled continually to ascribe the effects we know to some cause we do not know — to regard the manifestations we are conscious of as implying something manifested. We find it impossible to think of the world as constituted of appearances, and to exclude all thought of a reality of which they are appearances. The inconsistencies in the views set forth are in fact organic. Intellectual action being a perpetual forming of relations between the states from moment to moment passing, and being incapable of arresting itself, tends irresistibly to form them when it reaches the limit of intelligence. The inevitable effect of our mental constitution is that on reaching the limit thought rushes out to form a new relation and cannot form it. A conflict hence arises between an effort to pass into the Unknowable and an inability to pass — a conflict which involves the inconsistency of feeling obliged to think something and being unable to think it.

And here we come as before to the conclusion that while it is impossible for us to have a conception, there yet ever remains a consciousness — a consciousness of which no logical account can be given, but which is the necessary result of our mental action; since the perpetually-foiled endeavour to think the relation between Appearance and Reality, ever leaves behind a feeling that though a second term cannot be framed in thought yet there is a second term. This distinction, here emphasized as it was emphasized in §26, my critics have ignored. Their arguments are directed against one or other elements in a conception which they ascribe to me: forgetting that, equally with them, I deny the possibility of any conception, and affirm only that after all our futile attempts to conceive, there remains the undefinable substance of a conception — a consciousness which cannot be put into any shape.

But now let it be understood that the reader is not called on to judge respecting any of the arguments or conclusions contained in the foregoing five chapters and in the above paragraphs. The subjects on which we are about to enter are independent of the subjects thus far discussed; and he may reject any or all of that which has gone before, while leaving himself free to accept any or all of that which is now to come.

When drawing up the programme of the Synthetic Philosophy, it appeared to me that, in the absence of any statement of theologico-metaphysical beliefs, the general doctrine set forth might be misconstrued; and Part I, "The Unknowable," was written for the purpose of excluding the possible misconstructions. Unfortunately I did not foresee that Part I would be regarded as a basis for Part II; with the result that the acceptance or rejection of the conclusions in Part I, would be supposed to determine acceptance or rejection of those in Part II. Very many have in consequence been prevented from reading beyond this point.

But an account of the Transformation of Things, given in the pages which follow, is simply an orderly presentation of facts; and the interpretation of the facts is nothing more than a statement of the ultimate uniformities they present — the laws to which they conform. Is the reader an atheist? the exposition of these facts and these laws will neither yield support to his belief nor destroy it. Is he a pantheist? The phenomena and the inferences as now to be set forth will not force on him any incongruous implication. Does he think that God is immanent throughout all things, from concentrating nebulae to the thoughts of poets? Then the theory to be put before him contains no disproof of that view. Does he believe in a Deity who has given unchanging laws to the Universe? Then he will find nothing at variance with his belief in an exposition of those laws and an account of the results.

March, 1899.

Part II

The Knowable

Chapter 1

Philosophy Defined

§35. After concluding that we cannot know the ultimate nature of that which is manifested to us, there arise the questions — What is it that we know? In what sense do we know it? And in what consists our highest knowledge of it? Having repudiated as impossible the Philosophy which professes to formulate Being as distinguished from Appearance, it becomes needful to say what Philosophy truly is — not simply to specify its limits, but to specify its character within those limits. Given the sphere to which human intelligence is restricted, and there remains to define that product of human intelligence which may still be called Philosophy.

Here, we may fitly avail ourselves of the method followed at the outset — that of separating from conceptions which are partial1y or mainly erroneous, the element of truth they contain. As in the chapter on "Religion and Science," it was inferred that religious beliefs, wrong as they may severally be, nevertheless probably each contain an essential verity, and that this is most likely common to them all; so in this place it is to be inferred that past and present beliefs respecting the nature of Philosophy, are none of them wholly false, and that that in which they are true is that in which they agree. We have here, then, to do what was done there — to compare all opinions of the same genus; to set aside as more or less discrediting one another those elements in which such opinions differ; to observe what remains after the discordant components have been cancelled; and to find for this remaining component that expression which holds true throughout its divergent forms.

§36. Earlier speculations being passed over we see that among the Greeks, before there had arisen any notion of Philosophy in general, those particular forms of it from which the general notion was to arise, were hypotheses respecting some universal principle which was the essence of all kinds of being. To the question — "What is that invariable existence of which these are variable states?" there were sundry answers — Water, Air, Fire. A class of suppositions of this all-embracing character having been propounded, it became Possible for Pythagoras to conceive of Philosophy in the abstract, as knowledge the most remote from practical ends; and to define it as "knowledge of immaterial and eternal things;" "the cause of the material existence of things" being, in his view, Number. Thereafter, was continued a pursuit of Philosophy as some deepest explanation of the Universe, assumed to be possible, whether actually reached in any case or not. And in the course of this pursuit, various such interpretations were given as that "One is the beginning of all things;" that "the One is God;" that "the One is Finite;" that "the One is Infinite;" that "Intelligence is the governing principle of things;" and so on. From all which it is plain that the knowledge supposed to constitute Philosophy, differed from other knowledge in its exhaustive character. After the Sceptics had shaken men's faith in their powers of reaching such transcendent knowledge, there grew up a much-restricted conception of Philosophy. Under Socrates, and still more under the Stoics, Philosophy became little else than the doctrine of right living. Not indeed that the proper ruling of conduct, as conceived by sundry of the later Greek thinkers to constitute the subject-matter of Philosophy, answered to what was popularly understood by the proper ruling of conduct. The injunctions of Zeno were not of the same class as those which guided men in their daily observances, sacrifices, customs, all having more or less of religious sanction; but they were principles of action enunciated without reference to times, or persons, or special cases. What, then, was the constant element in these unlike ideas of Philosophy held by the ancients? Clearly this last idea agrees with the first, in implying that Philosophy seeks for wide and deep truths, as distinguished from the multitudinous detailed truths which the surfaces of things and actions present. By comparing the conceptions of Philosophy that have been current in modern times, we get a like result.

The disciples of Schelling and Fichte join the Hegelian in ridiculing the so-called Philosophy which has been current in England. Not without reason, they laugh on reading of "Philosophical instruments;" and would deny that any one of the papers in the Philosophical Transactions has the least claim to come under such a title. Retaliating on their critics, the English may, and most of them do, reject as absurd the imagined Philosophy of the German schools. They hold that whether consciousness does or does not vouch for the existence of something beyond itself, it at any rate cannot comprehend that something; and that hence, in so far as any Philosophy professes to be an Ontology, it is false. These two views cancel one another over large parts of their areas. The English criticism on the Germans, cuts off from Philosophy all that is regarded as absolute knowledge. The German criticism on the English tacitly implies that if Philosophy is limited to the relative, it is at any rate not concerned with those aspects of the relative which are embodied in mathematical formulae, in accounts of physical researches, in chemical analyses, or in descriptions of species and reports of physiological experiments. Now what has the too-wide German conception in common with the conception current among English men of science; which, narrow and crude as it is, is not so narrow and crude as their misuse of the word philosophical indicates? The two have this in common, that neither Germans nor English apply the word to unsystematized knowledge — to knowledge quite un-co-ordinated with other knowledge. Even the most limited specialist would not describe as philosophical, an essay which, dealing wholly with details, manifested no perception of the bearings of those details on wider truths.

The vague idea of Philosophy thus raised may be rendered more definite by comparing what has been known in England as Natural Philosophy with that development of it called Positive Philosophy. Though, as M. Comte admits, the two consist of knowledge essentially the same in kind; yet, by having put this kind of knowledge into a more coherent form, he has given it more of that character to which the term philosophical is applied. Without saying anything about the character of his co-ordination, it must be conceded that, by the fact of its co-ordination, the body of knowledge organized by him has a better claim to the title Philosophy, than has the comparatively-unorganized body of knowledge named Natural Philosophy.

If subdivisions of Philosophy be contrasted with one another or with the whole, the same implication comes out. Moral Philosophy and Political Philosophy, agree with Philosophy at large in the comprehensiveness of their reasonings and conclusions. Though under the head Moral Philosophy, we treat of human actions as right or wrong, we do not include special directions for behaviour in school, at table, or on the Exchange; and though Political Philosophy has for its topic the conduct of men in their public relations, it does not concert itself with modes of voting or details of administration. Both of these sections of Philosophy contemplate particular instances only as illustrating truths of wide application.

§37. Thus every one of these conceptions implies belief in a possible way of knowing things more completely than they are known through simple experiences, mechanically accumulated in memory or heaped up in cyclopaedias. Though in the extent of the sphere which they have supposed Philosophy to fill, men have differed and still differ very widely; yet there is a real if unavowed agreement among them in signifying by this title a knowledge which transcends ordinary knowledge. That which remains as the common element in these conceptions of Philosophy, after the elimination of their discordant elements, is — knowledge of the highest degree of generality. We see this tacitly asserted by the simultaneous inclusion of God, Nature, and Man, within its scope; or still more distinctly by the division of Philosophy as a whole into Theological, Physical, Ethical, etc. For that which characterizes the genus of which these are species, must be something more general than that which distinguishes any one species.

What must be the shape here given to this conception? Though persistently conscious of a Power manifested to us, we have abandoned as futile the attempt to learn anything respecting that Power, and so have shut out Philosophy from much of the domain supposed to belong to it. The domain left is that occupied by Science. Science concerts itself with the co-existences and sequences among phenomena; grouping these at first into generalizations of a simple or low order, and rising gradually to higher and more extended generalizations. But if so, where remains any subject-matter for Philosophy?

The reply is — Philosophy may still properly be the title retained for knowledge of the highest generality. Science means merely the family of the Sciences — stands for nothing more than the sum of knowledge formed of their contributions; and ignores the knowledge constituted by the fusion of these contributions into a whole. As usage has defined it, Science consists of truths existing more or less separated, and does not recognize these truths as entirely integrated. An illustration will make the difference clear.

If we ascribe the flow of a river to the same force which causes the fall of a stone, we make a statement that belongs to a certain division of Science. If, to explain how gravitation produces this movement in a direction almost horizontal, we cite the law that fluids subject to mechanical forces exert re-active forces which are equal in all directions, we formulate a wider truth, containing the scientific interpretations of many other phenomena; as those presented by the fountain, the hydraulic press, the steam-engine, the air-pump. And when this proposition, extending only to the dynamics of fluids, is merged in a proposition of general dynamics, comprehending the laws of movement of solids as well as of fluids, there is reached a yet higher truth; but still a truth that comes wholly within the realm of Science. Again, looking around at Birds and Mammals, suppose we say that air-breathing animals are hot-blooded; and that then, remembering how Reptiles, which also breathe air, are not much warmer than their media, we say, more truly, that animals (bulks being equal) have temperatures proportionate to the quantities of air they breathe; and that then, calling to mind certain large fish, as the tunny, which maintain a heat considerably above that of the water they swim in, we further correct the generalization by saying that the temperature varies as the rate of oxygenation of the blood; and that then, modifying the statement to meet other criticisms, we finally assert the relation to be between the amount of heat and the amount of molecular change — supposing we do all this, we state scientific truths that are successively wider and more complete, but truths which, to the last, remain purely scientific. Once more if, guided by mercantile experiences, we reach the conclusions that prices rise when the demand exceeds the supply; that commodities flow from places where they are abundant to places where they are scarce; that the industries of different localities are determined in their kinds mainly by the facilities which the localities afford for them; and if, studying these generalizations of political economy, we trace them all to the truth that each man seeks satisfaction for his desires in ways costing the smallest efforts — such social phenomena being resultants of individual actions so guided; we are still dealing with the propositions of Science only.

How, then, is Philosophy constituted? It is constituted by carrying a stage further the process indicated. So long as these truths are known only apart and regarded as independent, even the most general of them cannot without laxity of speech be called philosophical. But when, having been severally reduced to a mechanical axiom, a principle of molecular physics, and a law of social action, they are contemplated together as corollaries of some ultimate truth, then we rise to the kind of knowledge which constitutes Philosophy proper.

The truths of Philosophy thus bear the same relation to the highest scientific truths, that each of these bears to lower scientific truths. As each widest generalization of Science comprehends and consolidates the narrower generalizations of its own division; so the generalizations of Philosophy comprehend and consolidate the widest generalizations of Science. It is therefore a knowledge the extreme opposite in kind to that which experience first accumulates. It is the final product of that process which begins with a mere colligation of crude observations, goes on establishing propositions that are broader and more separated from particular cases, and ends in universal propositions. Or to bring the definition to its simplest and clearest form: — Knowledge of the lowest kind is un-unified knowledge; Science is partially-unified knowledge; Philosophy is completely-unified knowledge.

§38. Such, at least, is the meaning we must here give to the word Philosophy, if we employ it at all. In so defining it, we accept that which is common to the various conceptions of it current among both ancients and moderns — rejecting those elements in which these conceptions disagree. In short, we are simply giving precision to that application of the word which has been gradually establishing itself.

Two forms of Philosophy as thus understood, may be distinguished and dealt with separately. On the one hand, the things contemplated may be the universal truths: all particular truths referred to being used simply for proof or elucidation of these universal truths. On the other hand, setting out with the universal truths, the things contemplated may be the particular truths as interpreted by them. In both cases we deal with the universal truths; but in the one case they are passive and in the other case active — in the one case they form the products of exploration and in the other case the instruments of exploration. These divisions we may appropriately call General Philosophy and Special Philosophy respectively.

The remainder of this volume will he devoted to General Philosophy. Special Philosophy, divided into parts determined by the natures of the phenomena treated, will be the subject-matter of subsequent volumes.

Chapter 2

The Data of Philosophy

§39. Every thought involves a whole system of thoughts and ceases to exist if severed from its various correlatives. As we cannot isolate a single organ of a living body, and deal with it as though it had a life independent of the rest, so, from the organized structure of our cognitions, we cannot cut out one, and proceed as though it had survived the separation. The development of formless protoplasm into an embryo is a specialization of parts, the definiteness of which increases only as fast as their combination increases. Each becomes a distinguishable organ only on condition that it is bound up with others, which have simultaneously become distinguishable organs. Similarly, from the unformed material of consciousness, a developed intelligence can arise only by a process which, in making thoughts defined also makes them mutually dependent — establishes among them certain vital connexions the destruction of which causes instant death of the thoughts. Overlooking this all-important truth, however, speculators have habitually set out with some professedly — simple datum or data; have supposed themselves to assume nothing beyond this datum or these data; and have thereupon proceeded to prove or disprove propositions which were, by implication, already unconsciously asserted along with that which was consciously asserted.

This reasoning in a circle has resulted from the misuse of words: not that misuse commonly enlarged upon — not the misapplication or change of meaning whence so much error arises; but a more radical and less obvious misuse. Only that thought which is directly indicated by each word has been contemplated; while numerous thoughts indirectly indicated have been left out of consideration. Because a spoken or written word can be detached from all others, it has been inadvertently assumed that the thing signified by a word can be detached from the things signified by all other words. How profoundly this error vitiates the conclusions of one who makes it, we shall quickly see on taking a case. The sceptical metaphysician, wishing his reasonings to be as rigorous as possible, says to himself — "I will take for granted only this one thing." What now are the tacit assumptions inseparable from his avowed assumption? The resolve itself indirectly asserts that there is some other thing, or are some other things, which he might assume; for it is impossible to think of unity without thinking of a correlative duality or multiplicity. In the very act, therefore, of restricting himself, he takes in much that is professedly left out. Again, before proceeding he must give a definition of that which he assumes. Is nothing unexpressed involved in the thought of a thing as defined? There is the thought of something excluded by the definition — there is, as before, the thought of other existence. But there is much more. Defining a thing, or setting a limit to it, implies the thought of a limit; and limit cannot be thought of apart from some notion of quantity extensive, protensive, or intensive. Further, definition is impossible unless there enters into it the thought of difference; and difference, besides being unthinkable without having two things that differ, implies the existence of other differences than the one recognized; since without them there cannot have been formed the general conception of difference. Nor is this all. As before potted out (§24) all thought involves the consciousness of likeness: the one thing avowedly postulated cannot be known absolutely as one thing, but can be known only as of such or such kind — only as classed with other things in virtue of some common attribute. Thus, along with the single avowed datum, we have surreptitiously brought in a number of unavowed data — existence other than that alleged, quantity, number, limit, difference, likeness, class, attribute. Now in these unacknowledged postulates, we have the outlines of a general theory; and that theory can be neither proved nor disproved by the metaphysician's argument. Insist that his symbol shall be interpreted at every step into its full meaning, with all the complementary thoughts implied by that meaning, and you find already taken for granted in the premisses that which in the conclusion is asserted or denied.

In what way, then, must Philosophy set out? The developed intelligence is framed upon certain organized and consolidated conceptions of which it cannot divest itself; and which it can no more stir without using than the body can stir without help of its limbs. In what way, then, is it possible for intelligence, striving after Philosophy, to give any account of these conceptions, and to show either their validity or their invalidity? There is but one way. Those of them which are vital, or cannot be severed from the rest without mental dissolution, must be assumed as true provisionally. The fundamental intuitions that are essential to the process of thinking, must be temporarily accepted as unquestionable: leaving the assumption of their unquestionableness to be justified by the results.

§40. How is it to be justified by the results? As any other assumption is justified — by ascertaining that all the conclusions deducible from it correspond with the facts as directly observed — by showing the agreement between the experiences. There is no mode of establishing the validity of any belief except that of showing its congruity with all other beliefs. If we suppose that a mass which has a certain colour and lustre is the substance called gold, how do we proceed to prove that it is gold? We represent to ourselves certain other impressions which gold produces on us, and then observe whether, under the appropriate conditions, this particular mass produces on us such impressions. We remember that gold has a high specific gravity; and if, on poising this substance on the finger, we find that its weight is great considering its bulk, we take the correspondence between the represented impression and the presented impression as further evidence that the substance is gold. Knowing that gold, unlike most metals, is insoluble in nitric acid, we imagine to ourselves a drop of nitric acid placed on the surface of this yellow, glittering, heavy substance, without causing corrosion; and when, after so placing a drop of nitric acid, no effervescence or other change follows, we hold this agreement between the anticipation and the experience to be an additional reason for thinking that the substance is gold. And if, similarly, the great malleability assessed by gold we find to be paralleled by the great malleability of this substance; if, like gold, it fuses at about 2,000 deg.; crystallizes in octahedrons; is dissolved by selenic acid; and, under all conditions, does what gold does under such conditions; the conviction that it is gold reaches what we regard as the highest certainty — we know it to be gold in the fullest sense of knowing. For, as we here see, our whole knowledge of gold consists in nothing more than the consciousness of a definite set of impressions, standing in definite relations, disclosed under definite conditions; and if, in a present experience, the impressions, relations, and conditions, perfectly correspond with those in past experiences, the cognition has all the validity of which it is capable. So that, generalizing the statement, hypotheses, down even to those simple ones which we make from moment to moment in our acts of recognition, are verified when entire congruity is found between the states of consciousness constituting them, and certain other states of consciousness given in perception, or reflection, or both; and no other knowledge is possible for us than that which consists of the consciousness of such congruities and their correlative incongruities.

Hence Philosophy, compelled to make those fundamental assumptions without which thought is impossible, has to justify them by showing their congruity with all other dicta of consciousness. Debarred as we are from everything beyond the relative, truth, raised to its highest form, can be for us nothing more than perfect agreement, throughout the whole range of our experience, between those representations of things which we distinguish as ideal and those presentations of things which we distinguish as real. If, by discovering a proposition to be untrue, we mean nothing more than discovering a difference between a thing inferred and a thing perceived; then a body of conclusions in which no such difference anywhere occurs, must be what we mean by an entirely true body of conclusions.

And here, indeed, it becomes also obvious that, setting out with these fundamental intuitions provisionally assumed to be true, the process of proving or disproving their congruity with all other dicta of consciousness becomes the business of Philosophy; and the complete establishment of the congruity becomes the same thing as the complete unification of knowledge in which Philosophy reaches its goal.

§41. What is this datum, or rather, what are these data, which Philosophy cannot do without? Clearly one primordial datum is involved in the foregoing statement. Already by implication we have assumed that congruities and incongruities exist, and are cognizable by us. We cannot avoid accepting as true the verdict of consciousness that some manifestations are like one mother md some are unlike one another. Unless consciousness be a competent judge of the likeness and unlikeness of its states, there can never be established that congruity throughout the whole of our cognitions which constitutes Philosophy; nor can there ever be established that incongruity by which only any hypothesis, Philosophical or other, can be shown erroneous.

It is useless to say, as Sir W. Hamilton does, that "consciousness is to be presumed trustworthy until proved mendacious." It cannot be proved mendacious in this, its primordial act; since proof involves a repeated aCceptance of this primordial act. Nay more, the very thing supposed to be proved cannot be expressed without recognizing this primordial act as valid; since unless we accept the verdict of consciousness that they differ, mendacity and trustworthiness become identical. Process and product of reasoning both disappear in the absence of this assumption.

It may, indeed, be often shown that what, after careless comparison, were supposed to be like states of consciousness, are really unlike; or that what were carelessly supposed to be unlike, are really like. But how is this shown? Simply by a more careful comparison, mediately or immediately made. And what does acceptance of the revised conclusion imply? Simply that a deliberate verdict of consciousness is preferable to a rash one; or, to speak more definitely — that a consciousness of likeness or difference which survives critical examination must be accepted in place of one that does not survive — the very survival being itself the acceptance.

And here we get to the bottom of the matter. The permanence of a consciousness of likeness or difference, is our ultimate warrant for asserting the existence of likeness or difference; and, in fact, we mean by the existence of likeness or difference, nothing more than the permanent consciousness of it. To say that a given congruity or incongruity exists, is simply our way of saying that we invariably have a consciousness of it along with a consciousness of the compared things. We know nothing more of existence than continued manifestation.

§42. But Philosophy requires for its datum some substantive proposition. To recognize as unquestionable a certain fundamental process of thought, is not enough: we must recognize as unquestionable some fundamental product of thought, reached by this process. If Philosophy is completely — unified knowledge — if the unification of knowledge is to be effected only by showing that some ultimate proposition includes and consolidates all the results of experience; then, clearly, this ultimate proposition which has to be proved congruous with all others, must express a piece of knowledge, and not the validity of an act of knowing. Having assumed the trustworthiness of consciousness, we have also to assume as trustworthy some deliverance of consciousness.

What must this be? Must it not be one affirming the widest and most profound distinction which things present? An ultimate principle that is to unify all experience, must be co-extensive with all experience. That which Philosophy takes as its datum, must be an assertion of some likeness and difference to which all other likenesses and differences are secondary. If knowing is classifying, or grouping the like and separating the unlike; and if the unification of knowledge proceeds by arranging the smaller classes of like experiences within the larger, and these within the still larger; then, the proposition by which knowledge is unified, must be one specifying the antithesis between two ultimate classes of experiences, in which all others merge.

Let us consider what these classes are. In drawing the distinction between them, we cannot avoid using words which have implications wider than their meanings — we cannot avoid arousing thoughts that imply the very distinction which it is the object of the analysis to establish. Keeping this fact in mind, we can do no more than ignore the connotations of the words, and attend only to the things they avowedly denote.

§43. Setting out from the conclusion lately reached, that all things known to us are manifestations of the Unknowable, and suppressing every hypothesis respecting that which underlies one or other order of these manifestations; we find that the manifestations, considered simply as such, are divisible into two great classes, called by some impressions and ideas, The implications of these words are apt to vitiate the reasonings of those who use the words; and it is best to avoid the risk of making unacknowledged assumptions. The term sensation, too, commonly used as the equivalent of impression, implies certain psychological theories — tacitly, if not openly, postulates a sensitive organism and something acting upon it: and can scarcely be employed without bringing these postulates into the thoughts and including them in the inferences. Similarly, the phrase state of consciousness, as signifying either an impression or an idea, is objectionable. As we cannot think of a state without thinking of something of which it is a state, and which is capable of different states, there is involved a foregone conclusion — an undeveloped system of metaphysics. Here, accepting the inevitable implication that the manifestations imply something manifested, our aim must be to avoid any further implications. Though we cannot exclude further implications from our thoughts, and cannot carry on our argument without tacit recognitions of them, we can at any rate refuse to recognize them in the terms with which we set out. We may do this most effectually by classing the manifestations as vivid and faint respectively. Let us consider what are the several distinctions that exist between these.

And first a few words on this most conspicuous distinction which these names imply. Manifestations that occur under the conditions called those of perception (which conditions we must separate from all hypotheses, and regard as themselves a certain group of manifestations) are ordinarily far more distinct than those which occur under the conditions known as those of reflection, or memory, or imagination, or ideation. These vivid manifestations do, indeed, sometimes differ but little from the faint ones. When it is nearly dark we may be unable to decide whether a certain manifestation belongs to the vivid order or the faint order — whether as we say, we really see something or fancy we see it. In like manner, between a very feeble sound and the imagination of a sound, it is occasionally difficult to discriminate. But these exceptional cases are extremely rare in comparison with the enormous mass of cases in which, from instant to instant, the vivid manifestations distinguish themselves unmistakeably from the faint. Conversely, it now and then happens (though under conditions which we distinguish as abnormal) that manifestations of the faint order become so strong as to be mistaken for those of the vivid order. Ideal sights and sounds are in the insane so much intensified as to be classed with real sights and sounds — ideal and real being here supposed to imply no other contrast than that which we are considering. These cases of illusion, as we call them, bear, however, so small a ratio to the great mass of cases, that we may safely neglect them, and Say that the relative faintness of manifestations of the second order is so marked, that we are never in doubt as to their distinctness from those of the first order. Or if we recognize the exceptional occurrence of doubt, the recognition serves but to introduce the significant fact that we have other means of deciding to which order a particular manifestation belongs, when the test of comparative vividness fails us.

Manifestations of the vivid order precede, in our experience, those of the faint order. To put the facts in historical sequence — there is first a presented manifestation of the vivid order, and then, afterwards. may come a represented manifestation that is like it except in being much less distinct. After having those vivid manifestations known as particular places and persons and things, we can have those faint manifestations which we call recollections of the places, persons, and things, but cannot have these previously. Before tasting certain substances and smelling certain perfumes, we are without those faint manifestations called ideas of their tastes and smells; and where certain orders of the vivid manifestations are shut out (as the visible from the blind and the audible from the deaf) the corresponding faint manifestations never come into existence. It is true that special faint manifestations precede the vivid. What we call a conception of a machine may presently be followed by a vivid manifestation matching it — a so-called actual machine. But in the first place this occurrence of the vivid manifestation after the faint is not either spontaneous or easy like that of the faint after the vivid. And in the second place, though a faint manifestation of this kind may occur before the vivid one answering to it, yet its component parts may not. Without the foregoing vivid manifestations of wheels and bars and cranks, the inventor could have no faint manifestation of his new machine. Thus it cannot be denied that the two orders of manifestations are distinguished from one another as independent and dependent.

Note next that they form concurrent series; or rather let us call them, not series, which implies linear arrangements, but heterogeneous streams or processions. These run side by side; each now broadening and now narrowing, each now threatening to obliterate its neighbour and now in turn threatened with obliteration, but neither ever quite excluding the other from their common channel. Let us watch the mutual actions of the two currents. During what we call states of activity, the vivid manifestations predominate. We simultaneously receive many and varied presentations — a crowd of sights, sounds, resistances, tastes, odours, etc.; some groups of them changing and others temporarily fixed, but altering as we move; and when we compare in its breadth and massiveness this stream of vivid manifestations with the stream of faint ones, these last sink into relative insignificance. They never wholly disappear, however. Always along with the vivid manifestations, even in their greatest obtrusiveness, there goes a thread called thoughts constituted of the faint manifestations. Or if it be contended that the occurrence of a deafening explosion or an intense pain may for a moment exclude every idea, it must yet be admitted that such breach of continuity can never be immediately known as occurring; since the act of knowing is impossible in the absence of ideas. On the other hand, after certain vivid manifestations which we call the acts of closing the eyes and adjusting ourselves so as to enfeeble the vivid manifestations called pressures, sounds, etc., the faint manifestations become relatively predominant. The current of them, no longer obscured by the vivid current, grows distinct, and seems almost to exclude the vivid current. But the vivid manifestations, however small the current of them becomes, still continue: pressure and touch do not wholly disappear. It is only during the state termed sleep, that manifestations of the vivid order cease to be distinguishable as such, and those of the faint order come to be mistaken for them. And even of this we remain unaware till manifestations of the vivid order recur on awaking. We can never inter that manifestations of the vivid order have been absent, until they are again present; and can therefore never directly know them to be absent. Thus, of the two streams of manifestations, each preserves its continuity. As they flow side by side, either trenches on the other; but at no moment can it be said that the one has, then and there, broken through the other.

Besides this longitudinal cohesion there is a lateral cohesion, both of the vivid to the vivid and of the faint to the faint. The components of the vivid series are bound together by ties of co-existence as well as by ties of succession; and the components of the faint series are similarly bound together. Between the degrees of union in the two cases there are, however, marked and very significant differences. Let us observe them. Over a limited area of consciousness, as we name this double stream, lights and shades and colours and outlines constitute a group to which we give a certain name distinguishing it as an object; and while they continue present, these united vivid manifestations remain inseparable. So, too, is it with co-existing groups of manifestations: each persists as a special combination; and most of them preserve unchanging relations with those around. Such of them as do not — such of them as are capable of what we call independent movements, nevertheless show us a constant connexion between certain of the manifestations they include, along with a variable connexion of others. And though after certain vivid manifestations known as a change in the conditions of perception, there is a change in the proportions among the vivid manifestations constituting any group, their cohesion continues. Turning to the faint manifestations, we see that their lateral cohesions are much less extensive, and in most cases by no means so rigorous. After the group of feelings I call closing my eyes, I can represent an object now standing in a certain place, as standing in some other place, or as absent. While I look at a blue vase, I cannot separate the vivid manifestation of blueness from the vivid manifestation of a particular shape; but, in the absence of these vivid manifestations, I can separate the faint manifestation of the shape from the faint manifestation of blueness, and replace the last by a faint manifestation of redness, and I can also change the shape and the size of the vase to any extent. It is so throughout: the faint manifestations cling together to a certain extent, but most of them may be re-arranged with facility. Indeed none of the individual faint manifestations cohere in the same indissoluble way as do the individual vivid manifestations. Though along with a faint manifestation of pressure there is always some faint manifestation of extension, yet no particular faint manifestation of extension is bound up with a particular faint manifestation of pressure. So that whereas in the vivid order the individual manifestations cohere indissolubly usually in large groups, in the faint order the individual manifestations none of them cohere indissolubly, and are most of them loosely aggregated: the only indissoluble cohesions among them being between certain of their generic forms.

While the components of each current cohere strongly with their neighbours of the same current, most of them do not cohere strongly with those of the other current. Or, more correctly, we may say that the vivid current unceasingly flows on quite undisturbed by the faint current; and that the faint current, though often largely determined by the vivid, and always to some extent carried with it, may yet maintain a substantial independence, letting the vivid current slide by. We will glance at the interactions of the two. Save in peculiar cases hereafter to be dealt with, the faint manifestations fail to modify in the slightest degree the vivid manifestations. Those vivid manifestations, which I know as components of a landscape, as surgings of the sea, as whistlings of the wind, as movements of vehicles and people, are absolutely uninfluenced by the accompanying faint manifestations which I know as my ideas. On the other hand, the current of faint manifestations is always perturbed by the vivid. Frequently it consists mainly of faint manifestations which cling to the vivid ones, and are carried with them as they pass, memories and suggestions as we call them. At other times when, as we say, absorbed in thought, the disturbance of the faint current is but superficial. The vivid manifestations drag after them such few faint manifestations only as constitute recognitions of them: to each impression adhere certain ideas which make up the interpretation of it as such or such, and sometimes not even this cohesion happens. But there meanwhile flows on a main stream of faint manifestations wholly unrelated to the vivid manifestations — what we call a reverie, perhaps, or it may be a process of reasoning. And occasionally, during the state known as absence of mind, this current of faint manifestations so far predominates that the vivid current scarcely affects it at all. Hence, these concurrent series of manifestations, each coherent with itself longitudinally and transversely have but a partial coherence with one another. The vivid series is quite unmoved by its passing neighbour; and though the faint series is always to some extent moved by the adjacent vivid series, and is often carried bodily along with the vivid series, it may nevertheless become in great measure separate.

Yet another all-important difference has to be named. The conditions under which these two orders of manifestations occur, are unlike; and the conditions of occurrence of each order belong to itself. Whenever the immediate antecedents of vivid manifestations are traceable, they prove to be other vivid manifestations; and though we cannot say that the antecedents of the faint manifestations always lie wholly among themselves, yet the essential ones do. These statements need a good deal of explanation. Changes among the motions and sounds and aspects of what we call objects, are either changes that follow certain other motions, sounds, and aspects, or changes of which the antecedents are unapparent. Some of the vivid manifestations, however, occur only under conditions that seem of another order. Those known as colours and visible forms presuppose open eyes. But what is opening of the eyes, translated into the terms we are here using? Literally it is an occurrence of certain vivid manifestations. The preliminary idea of opening the eyes does, indeed, consist of faint manifestations, but the act of opening them consists of vivid manifestations. And the like is still more obviously the case with those movements of the eyes and the head which are followed by new groups of vivid manifestations. Similarly with the antecedents to the vivid manifestations which we distinguish as touch and pressure. All the changeable ones have for their conditions of occurrence certain vivid manifestations called sensations of muscular tension. It is true that the conditions to these conditions are manifestations of the faint order — those ideas of muscular actions which precede muscular actions. And here arises a complication, for what is called the body, is present to us as a set of vivid manifestations connected with the faint manifestations in a special way-a way such that in it alone certain vivid manifestations are capable of being produced by faint manifestations. There must be named, too, the kindred exception furnished by the emotions — an exception which, however, serves to enforce the general proposition. For while it is true that the emotions must be classed as vivid manifestations, which admit of being produced by the faint manifestations we call ideas; it is also true that because the conditions to their occurrence thus exist among the faint manifestations, we regard them as belonging to the same general aggregate as the faint manifestations — do not class them with such other vivid manifestations as colours, sounds pressures, smells, etc. But omitting these peculiar vivid manifestations which we know as muscular tensions and emotions, we may say of the rest, that their antecedents are manifestations belonging to their own class. In the parallel current we find a parallel truth. Though many manifestations of the faint order are partly caused by manifestations of the vivid order, which call up memories, as we say, and suggest inferences, yet these results mainly depend on certain antecedents belonging to the faint order. A cloud drifts across the Sun, and may or may not change the current of ideas: the inference that it will rain may arise, or the previous train of thought may continue — a difference determined by conditions among the thoughts. Again, such power as a vivid manifestation has of causing certain faint manifestations depends on the pre-existence of appropriate faint manifestations. If I have never heard a curlew, the cry which an unseen one makes, fails to produce an idea of the bird. And on remembering what various trains of thought are aroused by the same sight, we see that the occurrence of each faint manifestation chiefly depends on its relations to other faint manifestations that have gone before or co-exist.

Here we are introduced, lastly, to one of the most important of the differences between those two orders of manifestations. The conditions of occurrence are not distinguished solely by the fact that each set, when identifiable, belongs to its own order of manifestations. They are further distinguished in a very significant way. Manifestations of the faint order have traceable antecedents; can be made to occur by establishing their conditions of occurrence; and can be suppressed by establishing other conditions. But manifestations of the vivid order continually occur without previous presentation of their antecedents; and in many cases they persist or cease in such ways as to show that their antecedents are beyond control. The sensation known as a flash of lightning, breaks across the current of our thoughts absolutely without notice. The sounds from a band that strikes up in the street or from a crash of china in the next room, are not connected with any previously-present manifestations, either of the faint order or of the vivid order. Often these vivid manifestations, arising unexpectedly, persist in thrusting themselves across the current of the faint ones; which not only cannot directly affect them, but cannot even indirectly affect them. A wound produced by a blow from behind, is a vivid manifestation the conditions of occurrence of which were neither among the faint nor among the vivid; and the conditions to the persistence of which are bound up with the vivid manifestations in some unmanifested way. So that whereas in the faint order, the conditions of occurrence are always among the pre-existing or co-existing manifestations; in the vivid order, the conditions of occurrence are often neither present nor can be made present.

Let me briefly enumerate these distinctive characters. Manifestations of the one order are vivid and those of the other are faint. Those of the one order are originals, while those of the other are copies. The first form with one another a heterogeneous current that is never broken; and the second also form with one another a heterogeneous current that is never broken: or, to speak strictly, no breakage of either is ever directly known. Those of the first order cohere with one another, not only longitudinally but also transversely; as also do those of the second order with one another. Between manifestations of the first order the cohesions, both longitudinal and transverse, are indissoluble by any direct action of the second order; but between manifestations of the second order, these cohesions are most of them dissoluble with ease. While the members of each current are so coherent with one another that it cannot be broken, the two currents, running side by side, have but little coherence. The conditions under which manifestations of either order occur, themselves belong to that order; but whereas in the faint order the conditions are always present, in the vivid order they are often not present, but lie somewhere outside of the series. Seven separate characters, then, mark off these two orders of manifestations from one another.

§44. What is the meaning of this? The foregoing analysis was commenced in the belief that the proposition postulated by Philosophy, must affirm some ultimate classes of likenesses and unlikenesses, in which all other classes merge; and here we have found that all manifestations of the Unknowable are divisible into two such classes. What is the division equivalent to?

Obviously it corresponds to the division between object and Subject. This profoundest distinction among manifestations of the Unknowable, we recognize by grouping them into self and not-self. These faint manifestations, forming a continuous whole differing from the other in the quantity, quality, cohesion, and conditions of existence of its parts, we call the ego; and these vivid manifestations, bound together in relatively-immense masses, and having independent conditions of existence, we call the non-ego. Or rather, more truly — each order of manifestations carries with it the irresistible implication of some power that manifests itself; and by the words ego and non-ego respectively, we mean the power that manifests itself in the faint forms, and the power that manifests itself in the vivid forms.

This segregation of the manifestations and coalescence of them into two distinct wholes, is in great part spontaneous, and precedes all deliberate judgments; though it is endorsed by such judgments when they come to be made. For the manifestations of each order have not simply that kind of union implied by grouping them as belonging to the same class, but they have that much more intimate union implied by cohesion, Their cohesive union exhibits itself before any acts of classing take place. So that, in truth, these two orders of manifestations are substantially self-separated and self-consolidated. The members of each, by clinging to one another and parting from their opposites, themselves form the united wholes known as object and subject. It is this self-union of their members which gives to these wholes formed of them, their individualities as wholes, and that separateness from each other which transcends judgment; and judgment merely aids by assigning to their respective classes, such manifestations as have not distinctly united themselves with the rest of their kind.

One further perpetually-repeated act of judgment there is, indeed, which strengthens this fundamental antithesis, and gives a vast extension to one term of it. We continually learn that while the conditions of occurrence of faint manifestations are always to be found, the conditions of occurrence of vivid manifestations are often not to be found. We also continually learn that vivid manifestations which have no perceivable antecedents among the vivid manifestations, are like certain preceding ones which had perceivable antecedents among the vivid manifestations. Junction of these two experiences produces the irresistible belief that some vivid manifestations have conditions of occurrence existing out of the current of vivid manifestations — existing as potential vivid manifestations capable of becoming actual. And so we are made conscious of an indefinitely-extended region of power or being, not merely separate from the current of faint manifestations constituting the phenomenal ego, but lying beyond the current of vivid manifestations constituting the immediately-present portion of the phenomenal non-ego.

§45. In a very imperfect way, passing over objections and omitting needful explanations, I have thus indicated the nature and justification of that fundamental belief which Philosophy requires as a datum. I might, indeed, safely have assumed this ultimate truth; which Common Sense asserts, which every step in Science takes for granted, and which no metaphysician ever for a moment succeeded in expelling from consciousness. But as all that follows proceeds upon this postulate, it seemed desirable briefly to show its warrant, with the view of shutting out criticisms which might else be made. It seemed desirable to prove that this deepest cognition is neither, as the idealist asserts, an illusion, nor as the sceptic thinks, of doubtful worth, nor as is held by the natural realist, an inexplicable intuition; but that it is a legitimate deliverance of consciousness elaborating its materials after the laws of its normal action. While, in order of time, the establishment of this distinction precedes all reasoning; and while, running through our mental structure as it does, we are debarred from reasoning about it without taking for granted its existence; analysis nevertheless enables us to justify the assertion of its existence, by showing that it is also the outcome of a primary classification based on accumulated likenesses and accumulated differences. In other words — Reasoning, which is itself but a formation of cohesions among manifestations, here strengthens, by the cohesions it forms, the cohesions which it finds already existing.

Before proceeding a further preliminary is needed. The manifestations of the Unknowable, separated into the two divisions of self and not-self, are re-divisible into certain most general forms, the reality of which Science, as well as Common Sense, from moment to moment assumes. In the chapter on "Ultimate Scientific Ideas," it was shown that we know nothing of these forms, considered t themselves. As, nevertheless, we must continue to use the words signifying them, it is needful to say what interpretations are to be put on these words.

Chapter 3

Space, Time, Matter, Motion, and Force

§46. That sceptical state of mind which the criticism of Philosophy usually produce, is, in great measure, caused by the misinterpretation of words. These have by association acquired meanings quite different from those given to them in philosophical discussion; and the ordinary meanings being unavoidably suggested, there results more or less of that dream-like illusion which is so incongruous with our instinctive convictions. The word phenomenon and its equivalent word appearance, are in great part to blame for this. In ordinary speech these always imply visual perceptions. Habit almost, if not quite, disables us from thinking of appearance except as something seen; and though phenomenon has a more generalized meaning, yet we cannot rid it of associations with appearance. When, therefore, Philosophy proves that our knowledge of the external world can be but phenomenal — when it concludes that the things of which we are conscious are appearances; it inevitably suggests an illusiveness like that to which our visual perceptions are so liable. Good pictures show us that the aspects of things may be very nearly simulated by colours on canvas. The looking-glass distinctly proves how deceptive is sight when unverified by touch; as does also the apparent bend in a straight stick inclined in the water. And the cases in which we think we see something which we do not see, further shake our faith in vision. So that the implication of uncertainty has infected the very word appearance. Hence, Philosophy, by giving it an extended meaning, leads us to think of all our senses as deceiving us in the same way that our eyes do; and so makes us feel ourselves in a world of phantasms. Had phenomenon and appearance no such misleading associations, little, if any, of this mental confusion would result. Or if, when discussing the nature of our knowledge, we always thought of tactual impressions instead of visual impressions — if instead of the perceptions of objects yielded by our eyes we always insisted upon thinking of the perceptions yielded by our hands, the idea of unreality would in large measure disappear. Metaphysical criticism would then have merely the effect of proving to us that feelings of touch and pressure produced by an object give us no knowledge of its nature, at the same time that the criticism would by implication admit that there was a something which produced these feelings. It would prove to us that our knowledge consists simply of the effects wrought on our consciousness, and that the causes of those effects remain unknown; but it would not in doing this tend in any degree to disprove the existence of such causes: all its arguments tacitly taking them for granted. And when the two were always thought of in this immediate relation, there would be little danger of falling into the insanities of idealism.

Such danger as might remain, would disappear on making a further verbal correction. We increase the seeming unreality of that phenomenal existence which we can alone know; by contrasting it with a noumenal existence which we imagine would, if we could know it, be more truly real to us. But we delude ourselves with a verbal fiction. What is the meaning of the word real? In the interpretation given to it, the discussions of philosophy retain one element of the vulgar conception of things while they reject the rest, and create confusion by the inconsistency. The peasant, on contemplating an object, does not regard that which he is conscious of as something in himself, but believes it to be the external object itself: to him the appearance and the reality are one and the same thing. The metaphysician, however, while his words imply belief in a reality sees that consciousness cannot embrace it, but only the appearance of it; and so he transfers the appearance into consciousness and leaves the reality outside. This reality left outside, he continues to think of much in the same way that the peasant thinks of the appearance. The realness ascribed to it is constantly spoken of as though it were known apart from all acts of consciousness. It seems to be forgotten that the idea of reality can be nothing more than some mode of consciousness; and that the question to be considered is — What is the relation between this mode and other modes?

By reality we mean persistence in consciousness: a persistence which is either unconditional, as our consciousness of space, or which is conditional, as our consciousness of a body while grasping it. The real, as we conceive it, is distinguished solely by the test of persistence; for by this test we separate it from what we call the unreal. Between a person standing before us and the idea of such a person, we discriminate by our ability to expel the idea from consciousness and our inability, while looking at him, to expel the person from consciousness. And when in doubt as to the trustworthiness of some impression made on our eyes in the dusk, we settle the matter by observing whether the impression persists on closer inspection; and we predicate reality if the persistence is complete. How truly persistence is what we mean by reality, is shown in the fact that when, after criticism has proved that the real as presented in perception is not the objectively real, the vague consciousness which we retain of the objectively real, is of something which persists absolutely, under all changes of mode, form, or appearance. And the fact that we cannot form even an indefinite notion of the absolutely real, except as the absolutely persistent, implies that persistence is our ultimate test of the real whether as existing under its unknown form or under the form known to us.

Consequently, the result must be the same to us whether that which we perceive be the Unknowable itself, or an effect invariably wrought on us by the Unknowable. If, under certain conditions furnished by our constitutions, some Power of which the nature is beyond conception, always produces a certain mode of consciousness — if this mode of consciousness is as persistent as would be this Power were it in consciousness; the reality will be to consciousness as complete in the one case as in the other. Were Unconditioned Being itself present in thought, it could but be persistent; and if, instead, there is Being conditioned by the forms of thought, but no less persistent, it must be to us no less real.

Hence there may be drawn these conclusions: — First, that we have an indefinite consciousness of an absolute reality transcending relations, which is produced by the absolute persistence in us of something which survives all changes of relation. Second, that we have a definite consciousness of relative reality, which unceasingly persists in us under one or other of its forms, and under each form so long as the conditions of presentation are fulfilled; and that the relative reality, being thus continuously persistent in us, is as real to us as would be the absolute reality could it be immediately known. Third, that thought being possible only under relation, the relative reality can be conceived as such only in connexion with an absolute reality; and the connexion between the two being absolutely persistent in our consciousness, is real in the same sense as the terms it unites are real.

Thus then we may resume, with entire confidence, those realistic conceptions which Philosophy at first sight seems to dissipate. Though reality under the forms of our consciousness is but a conditioned effect of the absolute reality, yet this conditioned effect standing in indissoluble relation with its unconditioned cause, and being equally persistent with it so long as the conditions persist, is, to the consciousness supplying those conditions, equally real. Much as our visual perceptions, though merely symbols found to be the equivalents of tactual perceptions, are yet so identified with those tactual perceptions that we appear actually to see the solidity and hardness which we do but infer, and thus conceive as solid objects what are only the signs of solid objects; so, on a higher stage, do we deal with these relative realities as though they were the actual existences instead of effects of the actual existences. And we may legitimately continue so to deal with them as long as the conclusions to which they help us are understood as relative and not absolute.

This general conclusion it now remains to interpret specifically in its application to each of our ultimate scientific ideas.

§47* We think in relations. We have seen (Chap. iii. Part I) that ultimate modes of being cannot be known or conceived as they exist in themselves; that is, out of relation to our consciousness. We have seen, by analyzing the product of thought, that it always consists of relations, and cannot include anything deeper than the most general of these. On analyzing the process of thought, we found that cognition of the Absolute is impossible, because it presents neither relation nor its elements — difference and likeness. And lastly, it was shown that though by the relativity of our thought we are eternally debarred from knowing or conceiving Absolute Being; yet that this very relativity of our thought, necessitates that vague consciousness of Absolute Being which no mental effort can suppress. That relation is the universal form of thought, is thus a truth which all kinds of demonstration unite in proving. By the transcendentalists, certain other elements of consciousness are regarded as forms of thought, or more strictly of intuition, which is the ultimate component of thought. While relation would of necessity be admitted by them to be a universal mental form, they would class with it two others as also universal. Were their doctrine otherwise tenable, however, it must still be rejected if such alleged further forms are interpretable as generated by the primary form. If we think in relations, and if relations have certain universal forms, it is manifest that such universal forms of relations will become universal forms of consciousness. And if these further universal forms are thus explicable, it is superfluous, and therefore unphilosophical, to assign them an independent origin. Now relations are of two orders — relations of sequence, and relations of coexistence; of which the one is original and the other derived. The relation of sequence is given in every change of consciousness. The relation of co-existence, which cannot be originally given in a consciousness of which the states are serial, becomes distinguished only when it is found that certain relations of sequence have their terms presented in consciousness in either order with equal facility; while the others are presented only in one order. Relations of which the terms are not reversible, become recognized as sequences proper; while relations of which the terms occur indifferently in both directions, become recognized as co-existences. Endless experiences, which from moment to moment present both orders of these relations, render the distinction between them perfectly definite; and at the same time generate an abstract conception of each. The abstract of all sequences is Time. The abstract of all co-existences is Space. From the fact that in thought, Time is inseparable from sequence, and Space from co-existence, we do not here infer that Time and Space are original forms of consciousness under which sequences and co-existences are known; but we infer that our conceptions of Time and Space are generated, as other abstracts are generated from other concretes: the only difference being that the organization of experiences has, in these cases, been going on throughout the entire evolution of intelligence.

<* For the psychological conclusions briefly set forth in this section and the three sections following it, the justification will be found in the writer's Principles of Psychology.>

This synthesis is confirmed by analysis. Our consciousness of Space is a consciousness of co-existent Positions. A portion of space can be conceived only by representing its limits as co-existing in certain relative Positions; and each of its imagined boundaries, be it line or plane, can be thought of in no other way than as made up of co-existent positions in close proximity And since a position is not an entity — since the congeries of positions which constitute any conceived portion of space, and mark its bounds, are not sensible existences; it follows that the co-existent positions which make up our consciousness of Space are not co-existences in the full sense of the word (which implies realities as their terms), but are the blank forms of co-existences, left behind when the realities are absent; that is, are the abstracts of co-existences. The experiences out of which, during the evolution of intelligence, this abstract of all co-existences has been generated, are experiences of individual positions ascertained by touch; and each of such experiences involves the resistance of an object touched, and the muscular tensions which measure this resistance. By countless unlike muscular adjustments, involving unlike muscular tensions, different resisting positions are disclosed; and these, as they can be experienced in one order as readily as another, we regard as co-existing. But since, under other circumstances, the same muscular adjustments do not produce contacts with resisting positions, there result the same states of consciousness minus the resistances — blank forms of co-existence from which the co-existent objects before experienced are absent. And from a building up of these, too elaborate to be here detailed, results that abstract of all relations of co-existence which we call Space. It remains only to point out, as a truth hereafter to be recalled, that the experiences from which the consciousness of Space arises, are experiences of force, A plexus of muscular forces we ourselves exercise, constitutes the index of each position as originally disclosed to us; and the resistance which makes us aware of something existing in that position, is an equivalent of the pressure we consciously exert. Thus, experiences of forces variously correlated, are those from which our consciousness of Space is abstracted.

Our Space-consciousness being thus shown to be purely relative, what are we to say of that which causes it? Is there an absolute Space which relative Space in some sort represents? Is Space in itself a form or condition of absolute existence, producing in our minds a corresponding form or condition of relative existence? These are unanswerable questions. Our conception of Space is produced by some mode of the Unknowable; and the complete unchangeableness of our conception of it simply implies a complete uniformity in the effects wrought by this mode of the Unknowable upon us. But therefore to call it a necessary mode of the Unknowable is illegitimate. All we can assert is that Space is a relative reality; that our consciousness of this unchanging relative reality implies an absolute reality equally unchanging in so far as we are concerned; and that the relative reality may be unhesitatingly accepted in thought as a valid basis for our reasonings; which, when rightly carried on, will bring us to truths that have a like relative reality — the only truths which concern us or can possibly be known to us.

Concerning Time, relative and absolute, a parallel argument leads to parallel conclusions. These are too obvious to need specifying in detail.

§48. Our conception of Matter, reduced to its simplest shape, is that of co-existent positions that offer resistance; as contrasted with our conception of Space, in which the co-existent positions offer no resistance. We think of Body as bounded by surfaces that resist, and as made up throughout of parts that resist. Mentally abstract the co-existent resistances, and the consciousness of Body disappears, leaving behind it the consciousness of Space. And since the group of co-existing resistant positions gives us impressions of resistance whether we touch its near, its remote, its right, or its left side; it results that as different muscular adjustments indicate different co-existences, we are obliged to conceive every portion of matter as containing more than one resistant position — that is, as occupying Space. Hence the necessity we are under of representing to ourselves the ultimate elements of Matter as being at once extended and resistant: this being the universal form of our sensible experiences of Matter, becomes the form which our conception of it cannot transcend, however minute the fragments which imaginary subdivisions produce. Of these two inseparable elements, the resistance is Primary and the extension secondary. Occupied extension, or Body, being distinguished in consciousness from unoccupied extension, or Space, by its resistance, this attribute must clearly have precedence in the genesis of the idea. If, as was argued in the last section, the experiences, mainly ancestral, from which our consciousness of Space is abstracted, can be received only through impressions of resistance made on the organism; the implication is, that experiences of resistance being those from which the conception of Space is generated, the resistance-attribute of Matter must be regarded as primordial and the space-attribute as derivative. Whence it becomes clear that our experiences of force, are those out of which the idea of Matter is built. Matter as opposing our muscular energies, being immediately present to consciousness in terms of force; and its occupancy of Space being known by an abstract of experiences originally given in terms of force; it follows that forces, standing in certain correlations, form the whole content of our idea of Matter.

Such being our cognition of the relative reality, what are we to say of the absolute reality? We can only say that it is some mode of the Unknowable, related to the Matter we know as cause to effect. The relativity of our cognition of Matter is shown alike by the above analysis, and by the contradictions which are evolved when we deal with the cognition as an absolute one (§16). But. as we have lately seen, though known to us only under relation, Matter is as real in the true sense of that word, as it would be could we know it out of relation; and further, the relative reality which we know as Matter, is necessarily represented to the mind as standing in a persistent or real relation to the absolute reality. We may therefore deliver ourselves over, without hesitation, to those terms of thought which experience has organized in us. We need not in our physical, chemical, or other researches, refrain from dealing with Matter as made up of extended and resistant atoms; for this conception, necessarily resulting from our experiences of Matter, is not less legitimate than the conception of aggregate masses as extended and resistant. The atomic hypothesis, and the kindred hypothesis of an all-pervading ether consisting of units, are simply developments of those universal forms which the actions of the Unknowable have wrought in us. The conclusions logically worked out by their aid are sure to be in harmony with all others which these same forms involve, and will have a relative truth that is equally complete.

§49. The conception of Motion, as presented or represented in the developed consciousness, involves the conceptions of Space, of Time, and of Matter. A something perceived; a series of positions occupied by it in succession; and a group of co-existent positions united in thought with the successive ones — these are the constituents of the idea. And since, as we have seen, these are severally elaborated from experiences of force as given in certain correlations, it follows that from a further synthesis of such experiences, the idea of Motion is also elaborated. A certain other element in the idea, which is in truth its fundamental element (namely, the necessity which the moving body is under to go on changing its position), results immediately from the earliest experiences of force. Movements of different parts of the organism in relation to one another, are the first presented in consciousness. These, produced by the actions of the muscles, entail reactions On consciousness in the shape of sensations of muscular tension. Consequently, each stretching-out or drawing-in of a limb, is originally known as a series of muscular tensions, varying as the position of the limb changes. And this rudimentary consciousness of Motion, consisting of serial impressions of force, becomes inseparably united with the consciousnesses of Space and Time as fast as these are abstracted from other impressions of force. Or rather, out of this primitive conception of Motion, the adult conception of it is developed simultaneously with the development of the conceptions of Space and Time: all three being evolved from the more multiplied and varied impressions of muscular tension and objective resistance.

That this relative reality answers to some absolute reality it is needful only for form's sake to assert. What has been said above, respecting the Unknown Cause which produces in us the effects called Matter, Space, and Time, will apply, on simply changing the terms, to Motion.

§§ 50, 51. We come down, then, finally to Force, as the ultimate of ultimates. Though Space, Time, Matter, and Motion, are apparently all necessary data of intelligence, yet a psychological analysis (here indicated only in rude outline) shows us that these are either built up of, or abstracted from, experiences of Force. Matter and Motion as we know them are concretes built up from the contents of various mental relations; while Space and Time are abstracts of the forms of these various relations. Deeper down than these, however, are the primordial experiences of Force. A single impression of force is manifestly receivable by a sentient being devoid of mental forms. Grant but sensibility, with no established power of thought, and a force producing some nervous change, will still be presentable at the supposed seat of sensation. Though no single impression of force so received, could itself produce a consciousness (which implies relations between different states), yet a multiplication of such impressions, differing in kind and degree, would give the materials for the establishment of relations, that is, of thought. And if such relations differed in their forms as well as in their contents, the impressions of such forms would be organized simultaneously with the impressions they contained. It needs but to remember that consciousness consists of changes, to see that the ultimate datum of consciousness must be that of which change is the manifestation; and that thus the force by which we ourselves produce changes, and which serves to symbolize the cause of changes in general, is the final disclosure of analysis.

That this undecomposable mode of consciousness into which all other modes may be decomposed, cannot be itself the Power manifested to us through phenomena, has been already proved (§18). We saw that to assume identity of nature between the cause of changes as it exists absolutely, and that cause of change of which we are conscious in our own muscular efforts, betrays us into alternate impossibilities of thought. Force, as we know it, can be regarded only as a conditioned effect of the Unconditioned Cause — as the relative reality indicating to us an Absolute Reality by which it is immediately produced.

Chapter 4

The Indestructibility of Matter

§52. Not because the truth is unfamiliar, is it needful here to assert the indestructibility of Matter; but partly because the symmetry of our argument demands enunciation of this truth, and partly because the evidence on which it is accepted must be examined. Could it be shown, or could it with reason be supposed, that Matter, either in its aggregates or in its units, ever becomes nonexistent, it would be needful either to ascertain under what conditions it becomes non-existent, or else to confess that Science and Philosophy are impossible. For if, instead of having to deal with fixed quantities and weights, we had to deal with quantities and weights which are apt, wholly or in part, to be annihilated, there would be introduced an incalculable element, fatal to all positive conclusions. Clearly, therefore, the proposition that matter is indestructible must be deliberately considered.

So far from being admitted as a self-evident truth, this would, in primitive times, have been rejected as a self-evident error. There was once universally current, a notion that things could vanish into nothing, or arise out of nothing. If men did not believe this in the strict sense of the word (which would imply that the process of creation or annihilation was clearly represented in consciousness), they still believed that they believed it; and how nearly, in their confused thoughts, the one was equivalent to the other, is shown by their conduct. Nor, indeed, have dark ages and inferior minds alone betrayed this belief. In its dogmas respecting the beginning and end of the world, the current theology clearly implies it; and it may be questioned whether Shakespeare, in his poetical anticipation of a time when all things shall disappear and "leave not a wrack behind," was not under its influence. The accumulation of experiences, however, and still more the organization of experiences, has slowly reversed this conviction. All apparent proofs that something can come out of nothing, a wider knowledge has one by one cancelled. The comet which is suddenly discovered and nightly waxes larger, is proved not to be a newly-created body but a body which was until lately beyond the range of vision. The cloud formed a few minutes ago in the sky, consists not of substance that has just begun to be, but of substance that previously existed in a transparent form. And similarly with a crystal or a precipitate in relation to the fluid depositing it. Conversely, the seeming annihilations of matter turn out to be only changes of state. It is found that the evaporated water, though it has become invisible, may be brought by condensation to its original shape. Though from a discharged fowling-piece the gunpowder has disappeared, there have appeared in place of it certain gases which, in assuming a larger volume, have caused the explosion. Not, however, until the rise of quantitative chemistry, could the conclusion suggested by such experiences be harmonized with all the facts. When, having ascertained not only the combinations formed by various substances, but also the proportions in which they combine, chemists were enabled to account for the matter that had made its appearance or become invisible, scepticism was dissipated. And of the general conclusion thus reached, the exact analysis daily made, by which the same portion of matter is pursued through numerous disguises and finally separated, furnish never-ceasing confirmations.

Such has become the effect of this specific evidence, joined to that general evidence which the continued existence of familiar objects gives us, that the Indestructibility of Matter is now held by many to be a truth of which the negation is inconceivable.

§53. This last fact rises the question whether we have any higher warrant for this fundamental belief than the warrant of conscious induction. Before showing that we have a higher warrant, some explanations are needful.

The consciousness of logical necessity, is the consciousness that a certain conclusion is implicitly contained in certain premises explicitly stated. If, contrasting a young child and an adult, we see that this consciousness of logical necessity, absent from the one is present in the other, we are taught that there is a growing up to the recognition of certain necessary truths, merely by the unfolding of the inherited intellectual forms and facilities.

To state the case more specifically: — Before a truth can be known as necessary, two conditions must be fulfilled. There must be a mental structure capable of grasping the terms of the proposition and the relation alleged between them; and there must be such definite and deliberate mental representation of these terms, as makes possible a clear consciousness of this relation. Non-fulfilment of either condition may cause non-recognition of the necessity of the truth. Let us take cases.

The savage who cannot count the fingers on one hand, can frame no definite thought answering to the statement that 7 and 5 are 12; still less can he frame the consciousness that no other total is possible.

The boy adding up figures inattentively says to himself that 7 and 5 are 11; and may repeatedly bring out a wrong result by repeatedly making this error.

Neither the non-recognition of the truth that 7 and 5 are 12, which in the savage results from undeveloped mental structure, nor the assertion, due to the boy's careless mental action, that they make 11, leads us to doubt the necessity of the relation between these two separately-existing numbers and the sum they make when existing together. Nor does failure from either cause to apprehend the necessity of this relation, make us hesitate to say that when its terms are distinctly represented in thought, its necessity will be seen; and that, apart from multiplied experiences, this necessity becomes cognizable when structures and functions are so far developed that groups of 7 and 5 and 12 can be mentally grasped.

Manifestly, then, there are recognitions of necessary truths, as such, which accompany mental evolution. And there are ascending gradations in these recognitions. A boy who has intelligence enough to see that things which are equal to the same thing are equal to one another, may be unable to see that ratios which are severally equal to certain other ratios that are unequal to each other, are themselves unequal; though to a more-developed mind this last axiom is no less obviously necessary than the first.

All this which holds of logical and mathematical truths, holds, with change of terms, of physical truths. There are necessary truths in Physics for the apprehension of which, also, a developed and disciplined intelligence is required; and before such intelligence arises, not only may there be failure to apprehend the necessity of them, but there may be vague beliefs in their contraries. Up to comparatively-recent times, all mankind were in this state of incapacity respecting physical axioms; and the mass of mankind are so still. Effects are expected without causes of fit kinds; or effects extremely disproportionate to causes are looked for; or causes are supposed to end without effects.* But though many are unable to grasp physical axioms, it no more follows that physical axioms are not knowable a priori by a developed intellect, than it follows that logical relations are not necessary, because undeveloped intellects cannot perceive their necessity.

<* I knew a lady who contended that a dress folded up tightly, weighed more than when loosely folded up; and who under this belief, had her trunks made large that she might diminish the charge for freight! Another whom I know, ascribes the feeling of lightness which accompanies vigour. to actual decrease of weight; believes that by. stepping gently, she can press less upon the ground; and, when cross-questioned. asserts that. If placed in scales, she can make herself lighter by an act of will!>

It is thus with the notions which have been current respecting the creation and annihilation of Matter. In the first place, there has been a confounding of two radically-different things — disappearance of Matter from a visible form, say by evaporation, and passage of Matter from existence into non-existence. Until this confusion is avoided, the belief that Matter can be annihilated readily obtains currency. In the second place, the currency of it continues so long as there is not power of introspection enough to make manifest what results from the attempt to annihilate Matter in thought. But when the vague ideas arising in a nervous structure imperfectly organized, are replaced by the clear ideas arising in a definite nervous structure; this definite structure, moulded by experience into correspondence with external things, makes necessary in thought the relations answering to uniformities in things. Hence, among others, the conception of the Indestructibility of Matter.

For self-analysis shows this to be a datum of consciousness. Conceive space to be cleared of all bodies save one. Now imagine the remaining one not to be removed from its place, but to lapse into nothing while standing in that place. You fail. The space which was solid you cannot conceive becoming empty, save by transfer of that which made it solid. What is termed the ultimate incompressibility of Matter, is an admitted law of thought. However small the bulk to which we conceive a piece of matter reduced, it is impossible to conceive it reduced into nothing. While we can represent to ourselves its parts as approximated, we cannot represent to ourselves the quantity of matter as made less. To do this would be to imagine some of the parts compressed into nothing, which is no more possible than to imagine compression of the whole into nothing. Our inability to conceive Matter becoming non-existent, is consequent on the nature of thought. Thought consists in the establishment of relations. There can be no relation established, and therefore no thought framed, when one of the related terms is absent from consciousness. Hence it is impossible to think of something becoming nothing, for the same reason that it is impossible to think of nothing becoming something — the reason, namely, that nothing cannot become an object of consciousness. The annihilation of Matter is unthinkable for the same reason that the creation of Matter is unthinkable.

It must be added that no experimental verification of the truth. that Matter is indestructible, is possible without a tacit assumption of it. For all such verification implies weighing, and weighing assumes that the matter forming the weight remains the same.

§54. And here we are introduced to that which it most concerns us to observe — the nature of the perceptions by which the permanence of Matter is perpetually illustrated. These perceptions under all their forms simply reveal this — that the force which a given quantity of matter embodies remains always the same under the same conditions. A toy which long unseen produces in us a set of visual and tactual feelings like those produced in childhood is recognized as the same because it has the power of affecting us in the same ways. The downward strain of some sovereigns which the bank-clerk weighs to save himself the trouble of counting, proves the special amount of a special kind of Matter; and the goldsmith uses the same test when the shape of the Matter has been changed by a workman. So, too, with special properties. Whether a certain crystal is or is not diamond, is decided by its resistance to abrasion and the degree to which it bends light out of its course. And so the chemist when a piece of substance lately visible and tangible has been reduced to an invisible, intangible gas, but has the same weight, or when the quantity of a certain element is inferred from its ability to neutralize a given quantity of some other element, he refers to the amount of action which the Matter exercises as his measure of the amount of Matter.

Thus, then, by the Indestructibility of Matter, we reilly mean the indestructibility of the force with which Matter affects us. And this truth is made manifest not only by analysis of the a posteriori cognition, but equally so by analysis of the a priori one.*

<* Lest he should not have observed it, the reader must be warned that the terms "a priori truth" and "necessary truth," as used in this work, are to be interpreted not in the old sense, as implying cognitions wholly independent of experiences, but as implying cognitions that have been rendered organic by immense accumulations of experiences, received partly by the individual, but mainly by all ancestral individuals whose nervous systems he inherits. On referring to the Principles of Psychology (§§426-433), it will be seen that the warrant alleged for one of these irreversible ultimate convictions is that, on the hypothesis of Evolution, it represents an immeasurably-greater accumulation of experiences than can be acquired by any single individual.>

Chapter 5

The Continuity of Motion

§55. Like the Indestructibility of Matter, the Continuity of Motion, or, more strictly, of that something which has Motion for one of its sensible forms, is a truth on which depends the possibility of exact Science, and therefore of a Philosophy which unifies the results of exact Science. Motions, visible and invisible, of masses and of molecules, form the larger half of the phenomena to be interpreted; and if such motions might either proceed from nothing or lapse into nothing, there could be no scientific interpretation of them.

This second fundamental truth, like the first, is not self-evident to primitive men nor to the uncultured among ourselves. Contrariwise, to uninstructed minds the opposite seems self-evident. The facts that a stone thrown up soon loses its ascending motion, and that after the blow its fall gives to the Earth, it remains quiescent, apparently prove that the principle of activity* which the stone manifested may disappear absolutely. Accepting the dicta of unaided perception, all men once believed, and most believe still, that motion can pass into nothing, and ordinarily does so pass. But the establishment of certain facts having opposite implications, led to inquiries which have proved these appearances to be illusive. The discovery that the celestial motions do not diminish, raised the suspicion that a moving body, when not interfered with, will go on for ever without change of velocity; and suggested the question whether bodies which lose their motion, do not at the same time communicate as much motion to other bodies. It was a familiar fact that a stone would glide further over a smooth surface, as that of ice, presenting no small objects to which it could part with its motion by collision, than over a surface strewn with such small objects; and that a stick hurled into the air would travel a far greater distance than if hurled into a dense medium like water. Thus the primitive notion that moving bodies have an inherent tendency to stop — a notion which the Greeks did not get rid of, and which lasted till the time of Galileo — began to give way. It was further shaken by such experiments as those of Hooke, which proved that a top spins the longer in proportion as it is prevented from communicating motion to surrounding matter.

<* Throughout this chapter I use this phrase. not with any metaphysical meaning, but merely to avoid foregone conclusions.>

To explain here all disappearances of visible motions is out of the question. It must suffice to state, generally, that the molar motion which disappears when a bell is struck by its clapper, re-appears in the bell's vibrations and in the waves of air they produce; that when a moving mass is stopped by coming against a mass that is immovable, the motion which does not show itself in sound shows itself in molecular motion; and that when bodies rub against one another, the motion lost by friction is gained in the motion of molecules. But one aspect of this general truth, as it is displayed in the motions of masses, we must carefully contemplate; for, otherwise, the doctrine of the Continuity of Motion will be misapprehended.

§56. As expressed by Newton, the first law of motion is that "every body must persevere in its state of rest, Or of uniform motion in a straight line, unless it be compelled to change that state by forces impressed upon it."

With this truth may be associated the truth that a body describing a circular orbit round a centre which detains it by a tractive force, moves in that orbit with undiminished velocity.

The first of these abstract truths is never realized in the concrete, and the second of them is but approximately realized. Uniform motion in a straight line implies the absence of a resisting medium; and it further implies the absence of forces, gravitative or other exercised by neighbouring masses: conditions never fulfilled. So, too, the maintenance of a circular orbit by any celestial body, implies that there are no perturbing bodies, and that there is an exact adjustment between its velocity and the tractive force of its primary: neither requirement ever being conformed to. In actual orbits, sensibly elliptical as they are, the velocity is sensibly variable. And along with great eccentricity there goes great variation.

With the case of these celestial bodies which, moving in eccentric orbits, display at one time little motion and at another much motion, may be associated as partially analogous the case of the pendulum. With speed now increasing and now decreasing, the pendulum alternates between extremes at which motion ceases.

How shall we so conceive these allied phenomena as to express rightly the truth common to them? The first law of motion, nowhere literally fulfilled, is yet, in a sense, implied by these facts which seem at variance with it. Though in a circular orbit the direction of the motion is continually being changed, yet the velocity remains unchanged. Though in an elliptical orbit there is now acceleration and now retardation, yet the average speed is constant through successive revolutions. Though the pendulum comes to a momentary rest at the end of each swing, and then begins a reverse motion, yet the oscillation, considered as a whole, is continuous: friction and atmospheric resistance being absent, this alternation of states would go on for ever.

What, then, do these cases show us in common? That which vision familiarizes us with in Motion, and that which has thus been made the dominant element in our conception of Motion, is not the element of which we can allege continuity. If we regard Motion simply as change of place, then the pendulum shows us both that the rate of this change may vary from instant to instant, and that, ceasing at intervals, it may be afresh initiated.

But if what we may call the translation-element in Motion is not continuous, what is continuous? If, like Galileo, we watch a swinging chandelier, and observe, not the isochronism of its oscillations but the recurring reversal of direction, we are impressed with the fact that though, at the end of each swing, the translation through space ceases, yet there is something which does not cease; for the translation recommences in the opposite direction. And on remembering that when a violent push was given to the chandelier it described a larger arc, and was a longer time before the resistance of the air brought it to rest, we are shown that what continues to exist during its alternating movements is some correlative of the muscular effort which put it in motion. The truth forced on our attention is that translation through space is not itself an existence; and that hence the cessation of Motion, considered simply as translation, is not the cessation of an existence, but is the cessation of a certain sign of an existence.

Still there remains a difficulty If that element in the chandelier's motion of which alone we can allege continuity is the correlative of the muscular effort which moved, the chandelier, what becomes of this element at either extreme of the oscillation? Arrest the chandelier in the middle of its swing, and it gives a blow to the hand-exhibits some principle of activity such as muscular effort can give. But touch it at either turning point and it displays no such principle of activity. This has disappeared just as much as the translation through space has disappeared. How then, can it be alleged that though the Motion through space is not continuous, the principle of activity implied by the Motion is continuous?

Unquestionably the facts show that the principle of activity continues to exist under some form. When not perceptible it must be latent. How is it latent? A clue to the answer is gained on observing that though the chandelier when seized at the turning point of its swing, gives no impact in the direction of its late movement, it forthwith begins to pull in the opposite direction; and on observing, further, that its pull is great when the swing has been made extensive by a violent push. Hence the loss of visible activity at the highest point of the upward motion, is accompanied by the production of an invisible activity which generates the subsequent motion downwards. To conceive this latent activity gained, as an existence equal to the perceptible activity lost, is not easy; but we may help ourselves so to conceive it by considering cases of another class.

§57. When one who pushes against a door that has stuck fast, produces by great effort no motion, but eventually by a little greater effort bursts the door open, swinging it back and tumbling headlong into the room, he has evidence that the first muscular strain which did not produce transfer of matter through space, was yet equivalent to a certain amount of such transfer. Again, when a railway-porter gradually stops a detached carriage by pulling at the buffer, he shows us that (supposing friction, etc., absent) the slowly-diminished motion of the carriage over a certain space, is the equivalent of the constant backward strain put upon the carriage while it is traveling through that space. Carrying with us the conception thus reached, we will now consider a case which makes it more definite.

When used as a plaything, a ball fastened to the end of an india-rubber string yields a clear idea of the correlation between perceptible activity and latent activity. If, retaining one end of the string, a boy throws the ball from him horizontally, its motion is resisted by the increasing strain on the string; and the string, stretched more and more as the ball recedes, presently brings it to rest. Where now exists the principle of activity which the moving ball displayed? It exists in the strained thread of india-rubber. Under what form of changed molecular state it exists we need not ask. It suffices that the string is the seat of a tension generated by the motion of the ball, and equivalent to it. When the ball has been arrested the stretched string begins to generate in it an opposite motion, and continues to accelerate that motion until the ball comes back to the point at which the stretching of the string commenced — a point at which, but for loss by atmospheric resistance and molecular redistribution, its velocity would be equal to the original velocity. Here the truth that the principle of velocity, alternating between visible and invisible modes, does not cease to exist when the translation through space ceases to exist, is readily comprehensible; and it becomes easy to understand the corollary that at each point in the path of the ball, the quantity of its perceptible activity, plus the quantity which is latent in the stretched string, yields a constant sum.

Aided by this illustration, we can vaguely conceive what happens between bodies connected, not by a stretched string, but by a traction exercised by an invisible agency. It matters not to our general conception that the intensity of this traction varies in a different manner: decreasing as the square of the distance increases, but being practically constant for terrestrial distances. Notwithstanding these differences there is a truth common to the two cases. The weight of something held in the hand shows that between one body in space and another there exists a strain. This downward pull affects the hand as it might be affected by a stretched elastic string. Hence, when a body projected upwards and gradually retarded by gravity, finally stops, we must regard the principle of activity manifested as having become latent in the strain between it and the Earth — a strain of which the quantity is to be conceived as the product of its intensity and the distance through which it acts. Carrying a step further our illustration of the stretched string, will elucidate this. To simulate the action of gravity at terrestrial distances, let us imagine that when the attached moving body has stretched the elastic string to its limit, say at the distance of ten feet (from which point it is prevented from contracting back), a second like string could instantly be tied to the end of the first and to the body, which continuing its course stretched this second string, and so on with a succession of such strings, till the body was arrested. Then, obviously, the quantity of the principle of activity which the moving body possessed, but which has now become latent in the stretched strings, is measured by the number of such strings over which the strain extends. Now though the tractive force of the Earth is not exercised in a like way — though gravity, utterly unknown in its nature, is probably a resultant of actions pervading the ethereal medium; yet the above analogy suggests the belief that the principle of activity exhibited by a stone thrown up and presently arrested, has not ceased to exist, but has become so much imperceptible or latent activity in the medium occupying space; and that when the stone falls, this is re-transformed into its equivalent of perceptible activity. If we conceive the process at all, we must conceive it thus: otherwise, we have to conceive that a power has been changed into a space-relation, and this is inconceivable.

Here, then, is the solution of the difficulty The space-element of Motion is not in itself a thing. Change of position is not an existence, but the manifestation of an existence. This existence (supposing it not transferred by collision or friction) may cease to display itself as translation; but it can do so only by displaying itself as strain. And this principle of activity now shown by translation, now by strain, and often by the two together, is alone that which in Motion we can call continuous.

§58. What is this principle of activity? Vision gives us no idea of it. If by a mirror we cast the image of an illuminated object on to a dark wall, and then suddenly changing the attitude of the mirror make the reflected image pass from side to side, no thought arises that there is present in the image a principle of activity. Before we can conceive the presence of this, we must regard the visual impression as symbolizing something tangible. Sight of a moving body suggests a principle of activity which would be appreciable by skin and muscles were the body laid hold of. This principle of activity which Motion shows us, is the objective sense of effort. By pushing and pulling we get feelings which, generalized and abstracted, yield our ideas of resistance and tension. Now displayed by changing position and now by unchanging strain, this principle of activity is ultimately conceived by us under the single form of its equivalent muscular effort. So that the continuity of Motion, as well as the indestructibility of Matter, is really known to us in terms of Force. Here, however, the Force is of the kind known as Energy — a word applied to the force, molar or molecular, possessed by matter in action, as distinguished from the passive force by which matter maintains its shape and occupies space: a force which physicists appear to think needs no name.

§59. And now we reach the truth to be here especially noted. All proofs of the Continuity of Motion involve the postulate that the quantity of Energy is constant. Observe what results when we analyze the reasonings by which the Continuity of Motion is shown.

A particular planet is identified by its constant power to affect our eyes in a special way. Further, such planet has not been seen to move by the astronomer; but its motion is inferred from a comparison of its present position with the position it before occupied. This comparison proves to be a comparison between the different impressions produced on him by the different adjustments of his observing instruments. And the validity of the inferences. drawn depends on the truth of the assumption that these masses of matter, celestial and terrestrial, continue to affect his senses in the same ways under the same conditions. On going a step further back, it turns out that difference in the adjustment of his observing instrument, and by implication in the planet's position, is meaningless until shown to correspond with a certain calculated position which the planet must occupy, supposing that no motion has been lost. And if, finally, we examine the implied calculation, we find that it takes into account those accelerations and retardations which ellipticity of the orbit involves, as well as those variations of motion caused by adjacent planets — we find, that is, that the motion is concluded to be indestructible not from the uniform velocity of the planet, but from the constant quantity of motion exhibited after allowances have been made for the motions communicated to, or received from, other celestial bodies. And when we ask how this is estimated, we discover that the estimate assumes certain laws of force or energy; which laws, one and all, embody the postulate that energy cannot be destroyed.

Similarly with the a priori conclusion that Motion is continuous. That which defies suppression in thought (disciplined thought, of course), is the force which the motion indicates. We can imagine retardation to result from the actions of other bodies. But to imagine this we must imagine loss of some of the energy implied by the motion. We are obliged to conceive this energy as impressed in the shape of reaction on the bodies causing the retardation. And the motion communicated to them, we are compelled to regard as a product of the communicated energy. We can mentally diminish the velocity or space-element of motion, by diffusing the momentum or force-element over a larger mass of matter; but the quantity of this force-element is unchangeable in thought.*

<* This exposition differs in its point of view from the expositions ordinarily given; and some of the words employed, such as strain, have somewhat larger implications. Unable to learn anything about the nature of Force, physicists have, of late years, formulated ultimate physical truths in such ways as often tacitly to exclude the consciousness of Force: conceiving cause, as Hume proposed, in terms of antecedence and sequence only. "Potential energy," for example, is defined as constituted by such relations in space as permit masses to generate in one another certain motions, but as being in itself nothing. While this mode of conceiving the phenomena suffices for physical inquiries. It does not suffice for the purposes of philosophy. In the Principles of Psychology, §§ 347-350, I have shown that our ideas of Body, Space, Motion, are derived from our ideas of muscular tension, which are the ultimate symbols into which all our other mental symbols are interpretable. Hence to formulate phenomena in the proximate terms of Body, Space, Motion, while discharging from the concepts the consciousness of Force, is to acknowledge the superstructure while ignoring the foundation.

When, in 1875, I recast the foregoing chapter, and set forth more fully the doctrine contained in the answering chapters of preceding editions, I supposed myself to be alone in dissenting from the prevailing doctrine. But a year after, in the Philosophical Magazine for October, 1876, I was glad to see the same view enunciated and defended by Dr. Croll, in an essay "On the Transformation of Gravity." I commend his arguments to those who are not convinced by the arguments used above.

Let me add a remark concerning the nature of the question at issue. It is assumed that, as a matter of course, it is a question falling within the sphere of the mathematicians and physicists. I demur to the assumption. It is a question falling within the sphere of the psychologists — a question concerning the right interpretation of our ideas.>

Chapter 6

The Persistence of Force*

<* Some explanation of this title is needful. In the text itself are given the reasons for using the word "force" instead of the word "energy" and here I must say why I think "persistence" preferable to "conservation." Some two years ago (this was written in 1861) I expressed to my friend Prof. Huxley, my dissatisfaction with the (then) current expression — "Conservation of Force," assigning as reasons, first, that the word "conservation" implies a conserver and an act of conserving; and, second, that it does not imply the existence of the force before the particular manifestation of it which is contemplated. And I may now add, as a further fault, the tacit assumption that, without some act of conservation, force would disappear. All these implications are at variance with the conception to be conveyed. In place of "conservation" Prof. Huxley suggested persistence. This meets most of the objections; and though it may be urged that it does not directly imply pre-existence of the force at any time manifested, yet no word less faulty in this respect can be found. In the absence of a word coined for the Purpose, it seems the best; and as such I adopt it.>

§60. In the foregoing two chapters, manifestations of force of two fundamentally-different classes have been dealt with — the force by which matter demonstrates itself to us as existing, and the force by which it demonstrates itself to us as acting.

Body is distinguishable from space by its power of affecting our senses, and, in the last resort, by its opposition to our efforts. We can conceive of body only by joining in thought extension and resistance: take away resistance, and there remains only space. In what way this force which produces space-occupancy is conditioned we do not know. The mode of force which is revealed to us only by opposition to our own powers, may have for one of its factors the mode of force which reveals itself by the changes initiated in our consciousness. That the space a body occupies is in part determined by the degree of that activity of its molecules known as heat, is a familiar truth. Moreover, such molecular rearrangement as occurs when water is changed into ice, is shown to be accompanied by an evolution of force which may burst the containing vessel and give motion to the fragments. Nevertheless, the forms of our experience oblige us to distinguish between two modes of force; the one not a worker of change and the other a worker of change, actual or potential. The first of these — the space-occupying kind of force — has no specific name.

For the second kind of force, the specific name now accepted is "Energy." That which in the last chapter was spoken of as perceptible activity, is called by physicists, "actual energy;" and that which was there spoken of as latent activity, they call "potential energy." While including the mode of activity shown in molar motion, Energy includes also the several modes of activity into which molar motion is transformable — heat, light, etc. It is the common name for the power shown alike in the movements of masses and in the movements of molecules. To our perceptions this second kind of force differs from the first kind as being not intrinsic but extrinsic.

In aggregated matter as presented to sight and touch, this antithesis is, as above implied, much obscured. Especially in a compound substance, both the latent energy locked up in the chemically-combined molecules and the actual energy made perceptible to us as heat, complicate the manifestations of intrinsic force by the manifestations of extrinsic force. But the antithesis, here partially hidden, is clearly seen on reducing the data to their lowest terms — a unit of matter, or atom, and its motion. The force by which it exists is passive but independent; while the force by which it moves is active but dependent on its past and present relations to other atoms. These two cannot be identified in our thoughts. For as it is impossible to think of motion without something that moves, so it is impossible to think of energy without something possessing the energy.

While recognizing this fundamental distinction between that intrinsic force by which body manifests itself as occupying space, and that extrinsic force distinguished as energy, I here treat of them together as being alike persistent. And I thus treat of them together partly because, in our consciousness of them, there is the same essential element. The sense of effort is our subjective symbol for objective force in general, passive and active. Power of resisting that which we know as our own muscular strain, is the ultimate element in our idea of body as distinguished from space; and any motor energy which we give to body, or receive from it, is thought of as equal to a certain amount of muscular strain. The two consciousnesses differ essentially in this, that the feeling of effort common to them is in the last case joined with consciousness of change of position, but in the first case is not.*

<* Concerning the fundamental distinction here made between the space-occupying kind of force, and the kind of force shown by various modes of activity I am, as in the last chapter, at issue with some of my scientific friends. They do not admit that the conception of force is involved in the conception of a unit of matter. From the psychological point of view however, Matter, in all its properties, is the unknown cause of the sensations it produces in us; of which the one which remains when all ot hers are absent, is resistance to our efforts — a resistance we are obliged to symbolize as the equivalent of the muscular force it opposes. In imagining a unit of matter we may not ignore this symbol, by which alone a unit of matter can be figured in thought as an existence. It is not allowable to speak as though there remained a conception of an existence when that conception has been eviscerated — deprived of the element of thought by which it is distinguished from empty space. Divest the conceived unit of matter of the objective correlate to our subjective sense of effort, and the entire fabric of physical conceptions disappears.>

There is, however, a further and more important reason for here dealing with the proposition that Force under each of these forms persists. We have to examine its warrant.

§61. A little more patience is asked. We must reconsider the reasoning by which the indestructibility of Matter and the continuity of Motion are established, that we may see how impossible it is to arrive by parallel reasoning at the Persistence of Force.

In all three cases the question is one of quantity. Does the Matter or Motion, or Force, ever diminish in quantity? Quantitative science implies measurement, and measurement implies a unit of measure. The units of measure from which all others of any exactness are derived, are units of linear extension. Our units of linear extension are the lengths of masses of matter or the spaces between marks made on the masses, and we assume these lengths, or these spaces between marks, to remain unchanged while the temperature is unchanged. From the standard-measure preserved at Westminster, are derived the measures for trigonometrical surveys, for geodesy, the measurement of terrestrial arcs, and the calculations of astronomical distances, dimensions, etc., and therefore for Astronomy at large. Were these units of length, original and derived, irregularly variable, there could be no celestial dynamics, nor any of that verification yielded by it of the constancy of the celestial masses and of their energies. Hence, persistence of the space-occupying species of force cannot be proved, for the reason that it is tacitly assumed in every experiment or observation by which it is proposed to prove it. The like holds of the force distinguished as energy. The endeavour to establish this by measurement, takes for granted both the persistence of the intrinsic force by which body manifests itself as existing, and the persistence of the extrinsic force by which body acts. For it is from these equal units of linear extension, through the medium of the equal-armed lever or scales, that we derive our equal units of weight, or gravitative force; and only by means of these can we make those quantitative comparisons by which the truths of exact science are reached. Throughout the investigations leading the chemist to the conclusion that of the carbon which has disappeared during combustion, no portion has been lost, what is his repeatedly-assigned proof? That afforded by the scales. In what terms is the verdict of the scales given? In grammes — in units of weight — in units of gravitative force. And what is the total content of the verdict? That as many units of gravitative force as the carbon exhibited at first, it exhibits still. The validity of the inference, then, depends entirely upon the constancy of the units of force. If the force with which the portion of metal called a gramme-weight tends towards the Earth, has varied, the inference that matter is indestructible is vicious. Everything turns on the truth of the assumption that the gravitation of the weights is persistent; and of this no proof is assigned, or can be assigned. In the reasonings of the astronomer there is a like implication, from which we may draw the like conclusion. No problem in celestial dynamics can be solved without the assumption of some unit of force. This unit need not be, like a pound or a ton, one of which we can take direct cognizance. It is requisite only that the mutual attraction which some two of the bodies concerned exercise at a given distance, shall be taken as one; so that the other attractions with which the problem deals, may be expressed in terms of this one. Such unit being assumed, the motions which the respective masses will generate in one another in a given time, are calculated; and compounding these with the motions they already have, their places at the end of that time are predicted. The prediction is verified by observation. From this, either of two inferences may be drawn. Assuming the masses to be unchanged, their energies may be proved undiminished; or assuming their energies undiminished, the masses may be proved unchanged. But the validity of one or other inference depends wholly on the truth of the assumption that the unit of force is unchanged. Let it be supposed that the gravitation of the two bodies towards each other at the given distance has varied, and the conclusions drawn are no longer true. Nor is it only in their concrete data that the reasonings of terrestrial and celestial physics assume the Persistence of Force. The equality of action and reaction is taken for granted from beginning to end of either argument; and to assert that action and reaction are equal and opposite, is to assert that Force persists. The implication is that there cannot be an isolated force, but that any force manifested implies an equal antecedent force from which it is derived, and against which it is a reaction.

We might indeed be certain, even in the absence of any such analysis as the foregoing, that there must exist some principle which, as being the basis of science, cannot be established by science. All reasoned-out conclusions whatever must rest on some postulate. As before shown (§23), we cannot go on merging derivative truths in those wider truths from which they are derived, without reaching at last a widest truth which can be merged in no other, or derived from no other. And the relation in which it stands to the truths of science in general, shows that this truth transcending demonstration is the Persistence of Force. To this an ultimate analysis brings us down, and on this a rational synthesis must build up.

§62. But now what is the force of which we predicate persistence? That which the word ordinarily stands for is the consciousness of muscular tension — the feeling of effort which we have either when putting something in motion or when resisting a pressure. This feeling, however, is but a symbol.

In §18 it was said that though, since action and reaction are equal and opposite, we are obliged to think of the downward pull of a weight as equal to the upward pull which supports it, and though the thought of equality suggests kinship of nature, yet, as we cannot ascribe feeling to the weight, we are obliged to admit that Force as it exists beyond consciousness has no likeness to force as we conceive it, though there is between them the kind of equivalence implied by simultaneous variation. The effort of one who throws a cricket ball is followed by the motion of the ball through space, and its momentum is re-transformed into muscular strain in one who catches it. What the force was when it existed in the flying cricket ball it is impossible to imagine: we have no terms of thought in which to represent it. And it is thus with all the transformations of energy taking place in the world around. Those illustrations given in §66, showing the changes of form which energy undergoes and the equivalence between so much of it in one form and so much in another, fail to enlighten us respecting the energy itself. It assumes under this or that set of conditions this or that shape, and the quantity of it is not altered during its transformations. For that interpretation of things which is alone possible for us this is all we require to know — that the force or energy manifested, now in one way now in another, persists or remains unchanged in amount. But when we ask what this energy is, there is no answer save that it is the noumenal cause implied by the phenomenal effect.

Hence the force of which we assert persistence is that Absolute Force we are obliged to postulate as the necessary correlate of the force we are conscious of. By the Persistence of Force, we really mean the persistence of some Cause which transcends our knowledge and conception. In asserting it we assert an Unconditioned Reality, without beginning or end.

Thus, quite unexpectedly, we come down once more to that ultimate truth in which, as we saw, Religion and Science coalesce — the continued existence of an Unknowable as the necessary correlative of the Knowable.

Chapter 7

The Persistence of Relation Among Forces

§63. The first deduction to be drawn from the ultimate universal truth that force persists, is that the relations among forces persist. Supposing a given manifestation of force, under a given form and given conditions, be either preceded by or succeeded by some other manifestation, it must, in all cases where the form and conditions are the same, be preceded by or succeeded by such other manifestation. Every antecedent mode of the Unknowable must have an invariable connexion, quantitative and qualitative, with that mode of the Unknowable which we call its consequent.

For to say otherwise is to deny the persistence of force. If in any two cases there is exact likeness not only between those conspicuous antecedents which we call the causes, but also between those accompanying antecedents which we call the conditions, we cannot affirm that the effects will differ, without affirming either that some force has come into existence or that some force has ceased to exist. If the co-operative forces in the one case are equal to those in the other, each to each, in distribution and amount; then it is impossible to conceive the product of their joint action in the one case as unlike that in the other; without conceiving one or more of the forces to have increased or diminished in quantity; and this is conceiving that force is not persistent.

To impress the truth thus enunciated under its most abstract form, some illustrations will be desirable.

§64. Let two bullets, equal in weights and shapes, be projected with equal energies; then, in equal times, equal distances must be travelled by them. The assertion that one of them will describe an assigned space sooner than the other, though their initial momenta were alike and they have been equally resisted (for if they are unequally resisted the antecedents differ) is an assertion that equal quantities of force have not done equal amounts of work; and this cannot be thought without thinking that some force has disappeared into nothing or arisen out of nothing. Assume, further that during its night one of them has been drawn by the Earth a certain number of inches out of its original line of movement; then the other, which has moved the same distance in the same time, must have fallen just as far towards the Earth. No other result can be imagined without imagining that equal attractions acting for equal times, have produced unequal effects; which involves the inconceivable proposition that some action has been created or annihilated. Again, one of the bullets having penetrated the target to a certain depth, penetration by the other bullet to a smaller depth, unless caused by greater local density in the target, cannot be mentally represented. Such a modification of the consequents without modification of the antecedents, is thinkable only through the impossible thought that something has become nothing or nothing has become something.

It is thus not with sequences only, but also with simultaneous changes and permanent co-existences. Given charges of powder alike in quantity and quality, fired from barrels of the same structure, and propelling bullets of equal weights, sizes, and forms, similarly rammed down;* and it is a necessary inference that the concomitant actions which make up the explosion, will bear to one another like relations of quantity and quality in the two cases. The proportions among the different products of combustion will be equal. The several amounts of energy taken up in giving momentum to the bullet, heat to the gases, and sound on their escape, will preserve the same ratios. The quantities of light and smoke in the one case will be what they are in the other; and the two recoils will be alike. For no difference, of relation among these concurrent phenomena can be imagined as arising, without imagining it as arising by the creation or annihilation of energy.

<* This was written while muzzle-loading was still usual.>

That which holds between these two cases must hold among any number of cases; and that which here holds between comparatively simple antecedents and consequents, must hold however involved the antecedents become and however involved the consequents become.

§65. Thus Uniformity of Law, resolvable as we find it into the persistence of relations among forces, is a corollary from the persistence of force. The general conclusion that there exist constant connexions among phenomena, ordinarily regarded as an inductive conclusion only, is really a conclusion deducible from the ultimate datum of consciousness.

More than this may be said. Every apparent inductive proof of the uniformity of law itself takes for granted both the persistence of force and the persistence of relations among forces. For in the exact sciences, in which alone we may seek relations definite enough to prove uniformity, any alleged demonstration must depend on measurement; and as we have already seen, measurement, whether of matter or force, assumes that both are persistent in assuming that the measures have not varied. While at the same time every determination of the relations among them — in amount, proportion, direction, or what not — similarly implies measurement, the validity of which as before implies the persistence of force.

That uniformity of law thus follows inevitably from the persistence of force, will become more and more clear as we advance. The next chapter will indirectly supply abundant frustrations of it.

Chapter 8

The Transformation and Equivalence of Forces

§66. When, to the unaided senses, Science began to add supplementary senses in the shape of measuring instruments, men began to perceive various phenomena which eyes and fingers could not distinguish. Of known forms of force, minuter manifestations became appreciable; and forms of force before unknown were rendered cognizable and measurable. Where forces had apparently ended in nothing, and had been carelessly supposed to have actually done so, instrumental observation proved that effects had in every instance been produced: the forces having reappeared in new shapes. Here has at length arisen the inquiry whether the force displayed in each surrounding change, does not in the act of expenditure undergo metamorphosis into an equivalent amount of some other force or forces. And to this inquiry experiment is giving an affirmative answer, which becomes daily more decisive. Séguin, Mayer, Joule, Grove, and Helmholtz, are more than others to be credited with the enunciation of this doctrine. Let us glance at the evidence on which it rests.

Motion, wherever we can directly trace its genesis, we find had pre-existed as some other mode of force. Our own voluntary acts have always certain sensations of muscular tension as their antecedents. When, as in letting fall a relaxed limb we are conscious of a bodily movement requiring no effort, the explanation is that the effort was exerted in raising the limb to the position whence it fell. In this case, as in the case of an inanimate body descending to the Earth, the force accumulated by the downward motion is equal to the force previously expended in the act of elevation. Conversely, Motion that is arrested produces, under different circumstances, heat, electricity, magnetism, light. From the warming of the hands by rubbing them together, up to the ignition of a railway-brake by intense friction — from the lighting of detonating powder by percussion, up to the setting on fire a block of wood by a few blows from a steam-hammer; we have abundant instances in which heat arises as Motion ceases. It is uniformly found that the heat generated is great in proportion as the Motion lost is great; and that to diminish the arrest of motion by diminishing the friction, is to diminish the quantity of heat evolved. The production of electricity by Motion is illustrated equally in the boy's experiment with rubbed sealing-wax, in the common electrical machine, and in the apparatus for exciting electricity by the escape of steam. Wherever there is friction between heterogeneous bodies electrical disturbance is one of the consequences. Magnetism may result from Motion either immediately, as through percussion on steel, or mediately as through electric currents previously generated by Motion. And similarly, Motion may create light; either directly, as in the minute incandescent fragments struck off by violent collisions, or indirectly, as through the electric spark. "Lastly, Motion may be again reproduced by the forces which have emanated from Motion; thus, the divergence of the electrometer, the revolution of the electrical wheel, the deflection of the magnetic needle, are, when resulting from frictional electricity palpable movements reproduced by the intermediate modes of force, which have themselves been originated by motion."

That mode of force which we distinguished as Heat, is now regarded as molecular motion — not motion as displayed in the changed relations of sensible masses to one another, but as assessed by the units of which such sensible masses consist. Omitting cases in which there is structural rearrangement of the molecules, heated bodies expand; and expansion is interpreted as due to movements of the molecules in relation to one another: wider oscillations. That radiation through which anything of higher temperature than things around it, communicates Heat to them, is clearly a species of motion. Moreover, the evidence afforded by the thermometer that Heat thus diffuses itself, is simply a movement caused in the mercurial column. And that the molecular motion which we call Heat, may be transformed into visible motion, familiar proof is given by the steam-engine; in which "the piston and all its concomitant masses of matter are moved by the molecular dilatation of the vapour of water." Where Heat is absorbed without apparent result, modern inquiries have detected unobtrusive modifications: as in glass, the molecular state of which is so far changed, that a Alarized ray of light passing through it becomes visible, which it does not when the glass is cold; or as on polished metallic surfaces, which are altered in molecular structure by radiations from objects very close to them. The transformation of Heat into electricity occurs when dissimilar metals touching each other are heated at the point of contact: electric currents being so produced. Solid, incombustible matter put into heated gas, as lime into the Oxyhydrogen flame, becomes incandescent; and so exhibits the conversion of Heat into light. The production of magnetism by Heat, if it cannot be proved to take place directly, may be proved to take place indirectly through the agency of electricity. And through the same agency may be established the correlation of Heat and chemical affinity — a correlation which is directly shown by the marked influence Heat exercises on chemical composition and decomposition.

The transformations of Electricity into other modes of force are clearly demonstrable. Produced by the motion of heterogeneous bodies in contact, Electricity, through attractions and repulsions, will immediately reproduce motion in neighbouring bodies. In this case a current of Electricity magnetizes a bar of soft iron; and in that case the rotation of an equipped magnet generates currents of Electricity. Here is the cell of a battery in which, from the play of chemical affinities, an electric current results; and there, in the adjacent cell, is an electric current effecting chemical decomposition. In the conducting wire we witness the transformation of Electricity into heat; while in electric sparks and in the voltaic arc we see light produced. Molecular arrangement, too, is changed by Electricity: as instance the transfer of matter from pole to pole of a battery; the fractures caused by the disruptive discharge; the formation of crystals under the influence of electric currents. And then that, conversely, Electricity is directly generated by rearrangement of the molecules of matter, is shown when a storage-battery or accumulator is used.

How from Magnetism the other physical forces result, must be next briefly noted — briefly, because in each successive case the illustrations become in great part the obverse forms of those before given. That Magnetism produces motion is the ordinary evidence we have of its existence. In the magneto-electric machine a rotating magnet evolves electricity. and the electricity so evolved may immediately after exhibit itself as heat, light, or chemical affinity. Faraday' s discovery of the effect of Magnetism on polarized light, as well as the discovery that change of magnetic state is accompanied by heat, point to further like connexions. Lastly, experiments show that the magnetization of a body alters its internal structure; and that, conversely, the alteration of its internal structure, as by mechanical strain, alters its magnetic condition.

Improbable as it seemed, it is now proved that from Light also may proceed the like variety of agencies. Rays of light change the atomic arrangements of particular crystals. Certain mixed gases, which do not otherwise combine, combine in the sunshine. In some compounds light produces decomposition. Since the inquiries of photographers have drawn attention to the subject, it has been shown that "a vast number of substances, both elementary and compound, are notably affected by this agent, even those apparently the most unalterable in character, such as metals." And when a daguerreotype plate is connected with a proper apparatus "we get chemical action on the plate, electricity circulating through the wires, magnetism in the coil, heat in the helix, and motion in the needles."

The genesis of all other modes of force from Chemical Action, scarcely needs pointing out. The ordinary accompaniment of chemical combination is heat; and when the affinities are intense, light also is produced. Chemical changes involving alteration of bulk, cause motion, both in the combining elements and in adjacent masses of matter: witness the propulsion of a bullet by the explosion of gunpowder. In the galvanic battery we see electricity resulting from chemical composition and decomposition. While through the medium of this electricity, Chemical Action produces magnetism.

These facts, the larger part of which are culled from Grove's work on The Correlation of Physical Forces, show that each force is transformable, directly or indirectly, into the others. In every change Force (or Energy, as in these cases it is called) undergoes metamorphosis; and from the new form or forms it assumes, may subsequently result either the previous one or any of the rest, in endless variety of order and combination. It is further now manifest that the physical forces stand not simply in qualitative correlations with one another, but also in quantitative correlations. Besides proving that one mode of force may be transformed into another mode, experiments show that from a definite amount of one, the amounts of others that arise are definite. Ordinarily it is difficult to show this; since it mostly happens that the transformation of any force is not into some one of the rest but into several of them: the proportions being determined by ever-varying conditions. But in certain cases positive results have been reached. Mr. Joule has ascertained that the fall of 772 lb. through one foot, will raise the temperature of a pound of water one degree of Fahrenheit. Dulong, Petit, and Neumann, have proved a relation in amount between the affinities of combining bodies and the heat evolved during their combination. Between chemical action and voltaic electricity a quantitative connexion has been established by Faraday. The well-determined relations between the amounts of heat generated and of water turned to steam, or still better the known expansion produced in steam by each additional degree of heat, may be cited in further evidence. Hence it is no longer doubted that among the several forms which force assumes, the quantitative relations are fixed.

§67. Throughout the Cosmos this truth must invariably hold. Every change, or group of changes, going on in it, must be due to forces affiliable on the like or unlike forces previously existing; while from the forces exhibited in such change or changes must be derived others more or less transformed. And besides recognizing this necessary linking of the forces at any time manifested with those preceding and succeeding them, we must recognize the amounts of these forces as necessarily producing such and such quantities of results, and as necessarily limited to those quantities.

That unification of knowledge which is the business of Philosophy, is but little furthered by the establishment of this truth under its general form. We must trace it out under its leading special forms. Changes, and the accompanying transformations of forces, are everywhere in progress, from the movements of stars to the currents of commodities; and to comprehend the great fact that forces, unceasingly metamorphosed, are nowhere increased or decreased, it is requisite to contemplate the changes of all kinds going on that we may learn whence arise the forces they and what becomes of these forces. Of course if answerable at all, these questions can be answered only in the establish rudest way. The most we can hope is to establish a qualitative correlation that is indefinitely quantitative — quantitative to the extent of implying something like a due proportion between causes and effects.

Let us, then, consider the several classes of phenomena which the several concrete sciences deal with.

§68. The antecedents of those forces which our Solar System displays, belong to a past of which we can never have anything but inferential knowledge. Many and strong as are the reasons for believing the Nebular Hypothesis, we cannot yet regard it as more than an hypothesis. If, however, we assume that the matter of our Solar System was once diffused and had irregularities of shape and density such as existing nebulae display, or resulted from the coalescences of moving nebulous masses, we have, in the momenta of its parts, original and acquired forces adequate to produce the motions now going on.

Various stages in the formation of spiral nebulae imply that rotation in many cases results from concentration: whether always, there is no proof; for large nebulae are too diffused, small ones too dense, and others are seen too much edgeways, to yield evidence. But in the absence of adverse pre-arrangement some rotation may safely be inferred. So far as the evidence carries us, we perceive some quantitative relation between the motions generated and the gravitative forces expended in generating them. In the Solar System the outermost planets, formed from that matter which has travelled the shortest distance towards the common centre of gravity, have the smallest velocities. Doubtless this is explicable on the teleological hypothesis, since it is a condition to equilibrium. But without insisting that this is beside the question, it will suffice to point out that the like cannot be said of the planetary rotations. No such final cause can be assigned for the rapid axial movement of Jupiter and Saturn, or the slow axial movement of Mars. If, however, we look for the natural antecedents of these gyrations which all planets exhibit, the nebular hypothesis furnishes them; and they bear manifest quantitative relations to the rates of motions. For the planets that turn on their axes with extreme rapidity are those having large orbits — those of which the once-diffused components, probably formed into broad rings, moved to their centres of aggregation in immense spaces, and so acquired high velocities. While conversely; the planets which rotate with relatively small velocities, are those formed out of small nebulous rings.

"But what," it may be asked, "has in such case become of all that motion which ended in the aggregation of this diffused matter into solid bodies?" The answer is that it has been radiated in the form of heat and light; and this answer the evidence, so far as it goes, confirms. Geologists and physicists agree in concluding that the heat of the Earth's interior is but a remnant of the heat which once made molten the whole mass. The mountainous surfaces of the Moon and of Venus, indicating, as they do, crusts which have, like our own, been corrugated by contraction, imply that these bodies, too, have undergone refrigeration. Lastly we have in the Sun a still-continued production of the heat and light which result from the arrest of diffused matter moving towards a common centre of gravity . Here also, as before, a quantitative relation is traceable. Mars, the Earth, Venus, and Mercury, which severally contain comparatively small amounts of matter whose centripetal motion has been destroyed, have already lost nearly all the produced heat; while the great planets, Jupiter and Saturn, imply by their low specific gravity, as well as by the perturbations of their surfaces, that they still retain much heat. And then the Sun, a thousand times as great in mass as the largest planet, and having to give off an enormously greater quantity of heat and light due to that loss of molar motion which concentration entails, is still radiating with great intensity.

§69. Those forces which have wrought the surface of our planet into its present shape, are traceable to the primordial source just assigned. Geologic changes are either direct or indirect results of the unexpended heat caused by nebular condensation. They are commonly divided into igneous and aqueous — heads under which we may most conveniently consider them.

All those disturbances known as earthquakes, all those elevations and subsidences which they severally produce, all those accumulated effects of many such elevations and subsidences exhibited in ocean-basins, islands, continents, table-lands, mountain-chains, and all those formations which are distinguished as volcanic, geologists now regard as modifications of the Earth's crust caused by the actions and reactions of its interior. Even supposing that volcanic eruptions, extrusions of igneous rock, and upheaved mountain-chains, could be otherwise satisfactorily accounted for, it would be impossible otherwise to account for those wide-spread elevations and depressions whence continents and oceans result. Such phenomena as the fusion or agglutination of sedimentary deposits, the warming of springs, the sublimation of metals into the fissures where we find them as ores, may be regarded as positive results of the residuary heat of the Earth's interior; while fractures of strata and alterations of level are its negative results, since they ensue on its escape. The original cause of all these effects is still, however, as it has been from the first, the gravitating movement of the Earth's matter towards the Earth's centre; seeing that to this is due both the eternal heat itself and the collapse which takes place as it is radiated into space.

To the question — Under what forms previously existed the force which works out the geological changes classed as aqueous, the answer is less obvious. The effects of rain, of rivers, of winds, of waves, of marine currents, do not manifestly proceed from one general source. Analysis, nevertheless, proves that they have a common genesis. If we ask, — Whence comes the power of the river-current, bearing sediment down to the sea? the reply is, — The gravitation of water throughout the tract which this river drains. If we ask, — How came the water to be dispersed over this tract? the reply is, — It fell in the shape of rain. If we ask, — How came the rain to be in that position whence it fell? the reply is, — The vapour from which it was condensed was drifted there by the winds. If we ask, — How came this vapour to be at that height? the reply is, — It was raised by evaporation. And if we ask, — What force thus raised it? the reply is, — The Sun's heat. Just that amount of gravitative force which the Sun's heat overcame in raising the molecules of water, is given out again in the fall of those molecules to the same level. Hence the denudations effected by rain and rivers, during the descent of this condensed vapour to the level of the sea, are indirectly due to the radiated energy of the Sun. Similarly with the winds that transport the vapours hither and thither. Consequent as atmospheric currents are on differences of temperature (either general, as between the equatorial and polar regions, or special as between tracts of the Earth's surface having unlike physical characters) all such currents are due to that source from which the irregularly distributed heat proceeds. And if the winds thus originate, so too do the waves raised by them on the sea's surface. Whence it follows that whatever changes waves produce — the wearing away of cliffs, the breaking down of rocks into shingle, sand, and mud — are also traceable to the solar rays as their primary cause. The same may be said of ocean-currents. Generated as the larger ones are by the excess of heat which the ocean in tropical climates acquires from the Sun; and determined as the smaller ones are in part by local shapes of land; it follows that the distribution of sediment and other geological processes which these marine currents effect, are affiliable upon the energy the Sun radiates. The only aqueous agency otherwise originating is that of the tides — an agency which, equally with the others, is traceable to unexpended celestial motion. But making allowance for the changes this works, we conclude that the slow wearing down of continents and gradual filling up of seas, effected by rain, rivers, winds, waves, and ocean-streams, are the indirect effects of solar heat.

Thus we see that while the geological changes classed as igneous, arise from the still-progressing motion of the Earth's substance to its centre of gravity; the antagonistic changes classed as aqueous, arise from the still-progressing motion of the Sun's substance towards its centre of gravity.

§70. That the forces exhibited in vital actions, vegetal and animal, are similarly derived, is an obvious deduction from the facts of organic chemistry. Let us note first the physiological generalizations; and then the generalizations which they necessitate.

Plant-life is all directly or indirectly dependent on the heat and light of the Sun-directly dependent in the immense majority of plants, and indirectly dependent in plants which, as the fungi, flourish in the dark: since these, growing at the expense of decaying organic matter, mediately draw their forces from the same original source. Each plant owes the carbon and hydrogen of which it mainly consists, to the carbon dioxide and water contained in the surrounding air and earth. These must, however, be decomposed before their carbon and hydrogen can be assimilated. To overcome the affinities which hold their elements together requires the expenditure of energy; and this energy is supplied by the Sun. When, under fit conditions, plants are exposed to the solar rays, they give off oxygen and accumulate carbon and hydrogen. In darkness this process ceases. It ceases, too, when the quantities of light and heat received are greatly reduced, as in winter. Conversely, it is active when the light and heat are great, as in summer. And the like relation is seen in the fact that while plant-life is luxuriant in the tropics, it diminishes in temperate regions, and disappears as we approach the poles. Thus the irresistible inference is that the forces by which plants grow and carry on their functions, are forces which previously existed as solar radiations.

That in the main, the processes of animal life are opposite to those of vegetal life is a truth long current among men of science. Chemically considered, vegetal life is chiefly a process of de-oxidation, and animal life chiefly a process of oxidation; chiefly we must say, because in so far as plants are expenders of force for the purposes of organization, they are oxidizers; and animals, in some of their minor processes, are probably de-oxidizers. But with this qualification, the general truth is that while the plant, decomposing carbon dioxide and water and liberating oxygen, builds up the detained carbon and hydrogen (along with a little nitrogen and small quantities of other elements) into stem, branches, leaves, and seeds; the animal, consuming these branches, leaves, and seeds, and absorbing oxygen, re-composes carbon dioxide and water, forming also certain nitrogenous compounds in minor amounts. And while the decomposition effected by the plant is at the expense of energies emanating from the Sun, the re-composition effected by the animal is at the profit of these energies, which are liberated during the combination of such elements. Thus the movements, internal and external, of the animal, are re-appearances in new forms of a power absorbed by the plant under the shape of light and heat. Just as the solar forces expended in raising vapour from the sea's surface, are given out again in the fall of rain and rivers to the same level, and in the accompanying transfer of solid matters; so, the solar forces that in the plant raised certain chemical elements to a condition of unstable equilibrium, are given out again t the actions of the animal during the fall of these elements to a condition of stable equilibrium.

Besides thus tracing a qualitative correlation between these two great orders of organic activity, as well as between both of them and inorganic activities, we may rudely trace a quantitative correlation. Where vegetal life is abundant, we usually find abundant animal life; and as we advance from torrid to temperate and frigid climates, the two decrease together. Speaking generally, the animals of each class reach larger sizes in regions where vegetation is luxuriant, than in those where it is sparse.

Certain facts of development in both plants and animals, illustrate still more directly the truth we are considering. In pursuance of a suggestion made by Mr. (afterwards Sir William) Grove, Dr. Carpenter pointed out that a connexion between physical and vital forces is exhibited during incubation. The transformation of the unorganized contents of an egg into the organized chick, is a question of heat: withhold heat and the process does not commence; supply heat and it goes on while the temperature is maintained, but ceases when the egg is allowed to cool. The developmental changes can be completed only by keeping the temperature with tolerable constancy at a definite height for a definite time; that is — only by supplying a definite quantity of heat. Though the proclivities of the molecules determine the typical structure assumed, yet the energy supplied by the thermal undulations gives them the power of arranging themselves into that structure. In the metamorphoses of insects we may discern parallel facts. The hatching of their eggs is determined by temperature, as is also the evolution of the pupa into the imago; and both are accelerated or retarded according as heat is artificially supplied or withheld. It will suffice just to add, that the germination of plants presents like relations of cause and effect, as every season shows .

Thus then the various changes exhibited by the organic creation, whether considered as a whole, or in its two great divisions, or in its individual members, conform, so far as we can ascertain, to the general principle.

§71. Even after all that has been said in the foregoing part of this work, many will be alarmed by the assertion that the forces which we distinguish as mental, come within the same generalization. Yet there is no alternative but to make this assertion: the facts which justify, or rather which necessitate, it being abundant and conspicuous. At the same time they are extremely involved. The essential correlations occur in organs which are mostly invisible, and between forces or energies quite other than those which are apparent. Let us first take a superficial view of the evidence.

The modes of consciousness called pressure, motion, sound, light, heat, are effects produced in us by agencies which as otherwise expended, crush or fracture pieces of matter, generate vibrations in surrounding objects, cause chemical combinations, and reduce substances from a solid to a liquid form. Hence if we regard the changes of relative position, of aggregation, or of chemical union, thus arising, as being transformed manifestations of certain energies; so, too, must we regard the sensations which such energies produce in us. Any hesitation to admit this must disappear on remembering that the last correlations, like the first, are not qualitative only but quantitative. Masses of matter which, by scales or dynamometer, are shown to differ greatly in weight, differ as greatly in the feelings of pressure they produce on our bodies. In arresting moving objects, the strains we are conscious of are proportionate to the momenta of such objects as otherwise measured. The impressions of sounds given to us by vibrating strings, bells, or columns of air, are found to vary in strength with the amount of force applied. Fluids or solids proved to be markedly contrasted in temperature by the different degrees of expansion they produce in the mercurial column, produce in us correspondingly different degrees of the sensation of heat. And unlike intensities in our impressions of light, answer to unlike effects as measured by photometers.

Besides the correlation and equivalence between external physical forces and the mental forces generated by them under the form of sensations, there appears to be a correlation and equivalence between sensations and those physical forces which, in the shape of bodily actions, result from them. In addition to the excitements of secreting organs, sometimes traceable, there arise contractions of the involuntary muscles. Sensations increase the action of the heart, and recent experiments imply that the muscular fibres of the arteries are at the same time contracted. The respiratory muscles, too are stimulated. The rate of breathing is visibly and audibly augmented both by pleasurable and painful excitements of the nerves, if these reach any intensity. When the quantity of sensation is great, it generates contractions of the voluntary muscles, as well as of the involuntary ones. Violent pains cause violent struggles. The start that follows a loud sound, the wry face produced by an extremely disagreeable taste, the jerk with which the hand or foot is snatched out of very hot water exemplify the genesis of motions by feelings; and in these cases it is manifest that the quantity of bodily. action is proportionate to the quantity of sensation. even where pride causes suppression of the screams and groans expressive of great pain (also indirect results of muscular contraction), we may still see in the clenching of the hands, the knitting of the brows, and the setting of the teeth, that the bodily actions excited are as great, though less obtrusive in their results. If we take emotions instead of sensations, we find the correlation and equivalence similarly suggested. emotions of moderate intensity, like sensations of moderate intensity, generate little beyond excitement of the heart and vascular system, joined sometimes with increased action of glandular organs. But as the emotions rise in strength, the muscles of the face, body, and limbs, begin to move. Of examples may be mentioned the frowns, dilated nostrils, and stampings of anger; the contracted brows, and wrung hands, of grief; the laughs and leaps of joy; the frantic struggles of terror or despair. Passing over cases in which extreme agitation causes fainting, we see that whatever be the kind of emotion, there is a manifest relation between its amount, and the amount of muscular action induced, from the fidgettiness of impatience up to the almost convulsive movements accompanying great mental agony. To these several orders of evidence must be joined the further order, that between feelings and those voluntary motions which result from them, there comes the sensation of muscular tension, standing in manifest correlation with both — a correlation that is distinctly quantitative: the sense of strain varying, other things equal, directly as the quantity of momentum generated.

§71a. But now, reverting to the caution which preceded these two paragraphs, we have to note, first, that the facts do not prove transformation of feeling into motion but only a certain constant ratio between feeling and motion; and then we have further to note that what seems a direct quantitative correlation is illusory. For example, tickling is followed by almost uncontrollable movements of the limbs; but obviously there is no proportion between the amount of force applied to the surface and the amount of feeling or the amount of motion: rather there is an inverse proportion, for while a rough touch does not produce the effect a gentle one does. Even when it is recognized that the feeling is not the correlate of the external touching action but of a disturbance in certain terminal tactile structures, it still remains demonstrable that there is no necessary relation between the amount of such disturbance and the amount of feeling produced; for under some conditions muscular motion results without the intercalation of any feeling. When the spinal cord has been so injured as to cut off all nervous communication between the lower part of the body and the brain, tickling the sole of the foot produces convulsion of the leg more violent than it would do were it accompanied by sensation: there is a reflex transmission of the stimulus and genesis of motion without passage through consciousness. Cases of another class show that between central feelings or emotions and the muscular movements they initiate there are no fixed ratios: instance the sense of effort felt in making a small movement by one who is exhausted, or the inability of an patient to raise a limb from the bed however strong the desire to do it. So that neither the feelings peripherally initiated nor those centrally initiated, though they are correlated with motions, are quantitatively correlated. Even still more manifest becomes the lack of direct relation, either qualitative or quantitative, between outer stimuli and inner feelings, or between such inner feelings and muscular motions, when we contemplate the complex kinds of mental processes. The emotions and actions of a man who has been insulted are clearly not equivalents of the sensations produced by the words in his ears for the same words otherwise arranged, would not have caused them. The thing said bears to the mental action it excites, much the same relation that the pulling of a trigger bears to the subsequent explosion — does not produce the power but merely liberates it. Whence, then, arises this immense amount of nervous energy which a whisper or a glance may call forth?

Evidently we shall go utterly wrong if the problem of the transformation and equivalence of forces is dealt with as though an organism were simple and passive instead of being complex and active. In the living body there are already going on multitudinous transformations of energy very various in their natures, and between any physical action filling on it and any motion which follows, there are intercalated numerous changes of kind and quantity. The fact of chief significance for us here, is that organization is, under one of its aspects, a set of appliances for the multiplication of energies — appliances which, by their successive actions, make the energy eventually given out enormous as compared with the energy which liberated it. A physical stimulus affecting an organ of sense, is in some cases multiplied by local nervous agents; the augmented energy is again multiplied in some part of the spinal cord or in some higher ganglion; and this usually again multiplied in the cerebrum and discharged to the muscles, is there enormously multiplied in the contracting fibres. Of these transformations Only some carried on centrally have accompanying states of consciousness; so that, manifestly, there can be no quantitative equivalence either between the sensation and the original stimulus, or between it and the eventual motion. All we can say is that, other things equal, the three vary together; so that if in one case successive stages of increase are 1, 9, 27, 270 they in another case be 2, 18, 54, 540. This kind of correlation is all which the foregoing facts imply. But now let us glance at the indirect evidences which confirm the view that mental and physical forces are connected, though in an indirect way.

Nowadays no one doubts that mental processes and the resulting actions are contingent on the presence of a nervous system; and that, greatly obscured as it is by numerous and involved conditions, a general relation may be traced between the size of this system and the quantity of mental action as measured by its results. Further, this nervous apparatus has a chemical constitution on which its activity, depends; and there is one element in it between the amount of which and the amount of function performed, there is an ascertained connexion: the proportion of phosphorus present in the brain being the smallest in infancy, old age, and idiotcy, and the greatest during the prime of life. Note, next, that the evolution of thought and emotion varies, other things equal, with the supply of blood to the brain. On the one hand, an arrest of the cerebral circulation from stoppage of the heart, immediately entails unconsciousness. On the other hand, excess of cerebral circulation (unless it is such as to cause undue pressure) results in unusual excitement. Not the quantity only but also the condition, of the blood passing through the brain, influences the mental manifestations. The arterial currents must be duly aerated, to produce the normal amount of cerebration. If the blood is not allowed to exchange its carbon dioxide for oxygen, there results asphyxia, with its accompanying stoppage of ideas and feelings. That the quantity of consciousness is, other things equal, determined by the constituents of the blood, is unmistakably seen in the exaltation which certain vegeto-alkalies commonly produce when taken into it. The gentle exhilaration which tea and coffee create, is familiar to all; and though the gorgeous imaginations and intense feelings produced by opium and hashish, have been experienced by few (in this country at least), the testimony of those who have experienced them is sufficiently conclusive. Yet another proof that the genesis of the mental energies depends on chemical change, is afforded by the fact that the effete products separated from the blood by the kidneys, vary in character with the amount of cerebral action. Excessive activity of mind is accompanied by excretion of an unusual quantity of the alkaline phosphates.

§71b. But now after recognizing the classes of facts which unite to prove that the law of metamorphosis, and in a partial way the law of equivalence, holds between physical energies and nervous energies, let us enter upon the ultimate question — What is the nature of the relation between nervous energies and mental states? how are we to conceive molecular changes in the brain as producing feelings, or feelings as producing molecular changes which end in motion?

In his lecture on Animal Automatism, Prof. Huxley set forth the proofs that alike in animals and in Man, the great mass of those complex actions which we associate with purpose and intelligence may be performed automatically: and contended that the consciousness which ordinarily accompanies them is outside the series of changes constituting the nervous coordination — does not form a link in the chain but is simply a "concomitant" or a "collateral product." In so far as it correlates the nervous actions by which our bodily and mental activities are carried on, with physical forces in general, Prof. Huxley's conclusion accords with the conclusions above set forth; but in so far as it regards the accompanying states of consciousness as collateral products only, and not as factors in any degree, it differs from them. Here I cannot do more than indicate the set of evidences by which I think my own conclusion is supported if not justified.

One of them we have in the facts of habit, which prove that states of consciousness which were at first accompaniments of sensory impressions and resulting motions, gradually cease to be concomitants. The little boy who is being taught to read has definite perceptions and thoughts about the form and sound of each letter, but in maturity all these have lapsed, so that only the words are consciously recognized: each letter produces its effect automatically. So, too, the girl learning to knit is absorbed in thinking of each movement made under the direction of her eyes, but eventually the movements come to be performed almost like those of a machine while her mind is otherwise occupied. Such cases seem at variance with the belief that consciousness is outside the lines of nervous communication, and suggest, rather that it exists in any line of communication in course of establishment and disappears when the communication becomes perfect. If it is not a link in the line, it is not easy to see how these changes can arise.

Sundry facts appear to imply that consciousness is needful as an initiator in cases where there are no external stimuli to set up the co-ordinated nervous changes: the nervous structures, though capable of doing everything required if set going, are not set going unless there a rises an idea. Now this implies that an idea, or co-ordinated set of feelings, has the power of working changes in the nervous centres and setting up motions: the state of consciousness is a factor.

Then what we may call passive emotions — emotions which do not initiate actions — apparently imply that between feelings and nervous changes there is not merely a concomitance but a physical nexus. Intense grief or anxiety in one who remains motionless, is shown to be directly dependent on nervous changes by the fact that there is an unusual excretion of phosphates by the kidneys. Now unless we suppose that in such cases there is great activity of certain nervous plexuses ending in nothing, we must say that the feeling is a product of the molecular changes in them.

Once more there is the question — if feeling is not a factor how is its existence to be accounted for? To any one who holds in full the Cartesian doctrine that animals are automata, and that a howl no more implies feeling than does the bark of a toy dog, I have nothing to say. But whoever does not hold this, is obliged to hold that as we ascribed anger and affection to our fellow-men, though we literally know no such feelings save in ourselves, so must we ascribe them to animals under like conditions, if so, however — if feelings are not factors and the appropriate actions might be automatically performed without them — then, on the supernatural hypothesis it must be assumed that feelings were given to animals for no purpose, and on the natural hypothesis it must be assumed that they have arisen to do nothing.

§71c. But whether feeling is only a concomitant of certain nervous actions, or whether it is, as concluded above, a factor in such actions, the connexion between the two is inscrutable. If we suppose that in which consciousness inheres to be an immaterial something, not implicated in these nervous actions but nevertheless affected by them in such way as to produce feeling, then we are obliged to conceive of certain material changes — molecular motions — as producing changes in something in which there is nothing to be moved; and this we cannot conceive. If, on the other hand, we regard this something capable of consciousness, as so related to certain nervous changes that the feelings arising in it jot them in producing muscular motions, then we meet the same difficulty under its converse aspect. We have to think of an immaterial something — a something which is not molecular motion — which is capable of affecting molecular motions: we have to endow it with the power to work effects which, so far as our knowledge goes, can be worked only by material forces. So that this alternative, too, is in the last resort inconceivable.

The only supposition having consistency is that that in which consciousness inheres is the all-pervading ether. This we know can be affected by molecules of matter in motion and conversely can affect the motions of molecules; as witness the action of light on the retina. In pursuance of this supposition we may assume that the ether which pervades not only all space but all matter, is, under special conditions in certain parts of the nervous system, capable of being affected by the nervous changes in such way as to result in feeling, and is reciprocally capable under these conditions of affecting the nervous changes. But if we accept this explanation we must assume that the potentiality of feeling is universal, and that the evolution of feeling in the ether takes place only under the extremely complex conditions occurring in certain nervous centres. This, however, is but a semblance of an explanation, since we know not what the ether is, and since, by the confession of those most capable of judging, no hypothesis that has been framed accounts for all its powers. Such an explanation may be said to do no more than symbolize the phenomena by symbols of unknown natures.

Thus though the facts oblige us to say that physical and psychical actions are correlated, and in a certain indirect way quantitatively correlated, so as to suggest transformation, yet how the material affects the mental and how the mental affects the material, are mysteries which it is impossible to fathom. But they are not profounder mysteries than the transformations of the physical forces into one another. They are not more completely beyond our comprehension than the natures of Mind and Matter. They have simply the same insolubility as all other ultimate questions. We can learn nothing more than that here is one of the uniformities in the order of phenomena.

§72. If the general law of transformation and equivalence holds of the forces we class as vital and mental, it must hold also of those which we class as social. Whatever takes place in a society results either from the undirected physical energies around, from these energies as directed by men, or from the energies of the men themselves.

While, as among primitive tribes, men's actions are mainly independent of one another, social forces can scarcely be said to exist: they come into existence along with co-operation. The effects which can be achieved only by the joint actions of many, we may distinguish as social. At first these are obviously due to accumulated individual efforts, but as fast as societies become large and highly organized, they acquire such separateness from individual efforts as to give them a character of their own. The network of roads and railways and telegraph wires — agencies in the formation of which individual labours were so merged as to be practically lost — serve to carry on a social life that is no longer thought of as caused by the independent doings of citizens. The prices of stocks, the rates of discount, the reported demand for this or that commodity, and the currents of men and things setting to and from various localities, show us large movements and changes scarcely at all affected by the lives and deaths and deeds of persons. But these and multitudinous social activities displayed in the growth of towns, the streams of traffic in their streets, the daily issue and distribution of newspapers, the delivery of food at people's doors, etc., are unquestionably transformed individual energies, and have the same source as these energies — the food which the population consumes. The correlation of the social with the physical forces through the intermediation of the vital ones, is, however, best shown in the different amounts of activity displayed by the same society according as its members are supplied with different amounts of force from the external world. A very bad harvest is followed by a diminution of business. Factories are worked half-time railway traffic falls; retailers find their sales lessened; and if the scarcity rises to famine, a thinning of the population still more diminishes the industrial vivacity . Conversely, an unusually abundant supply of food, occurring under conditions not otherwise unfavourable, both excites the old producing and distributing agencies and sets up new ones. The surplus social energy finds vent in speculative enterprises. Labour is expended in opening new channels of communication. There is increased encouragement to those who furnish the luxuries of life and minister to the aesthetic faculties. There are more marriages, and a greater rate of increase in population. Thus the society grows larger, more complex, and more active. When the whole of the materials for subsistence are not drawn from the area inhabited, but are partly imported, the people are still supported by certain harvests elsewhere grown at the expense of certain physical forces, and the energies they expend originate from them.

If we ask whence come these physical forces, the reply is of course as heretofore — the Sun's rays. Based as the life of a society is on animal and vegetal products, and dependent as these are on the light and heat of the Sun, it follows that the changes wrought by men as socially organized, are effects of forces having a common origin with those which produce all the other orders of changes we have analyzed. Not only is the energy extended by the horse harnessed to the plough, and by the labourer guiding it, derived from the same reservoir as is the energy of the cataract and the hurricane; but to this same reservoir are traceable those subtler and more complex manifestations of energy which humanity, as socially embodied, evolves. The assertion is startling but it is an unavoidable deduction.

Of the physical forces that are directly transformed into social ones, the like is to be said. Currents of air and water, which before the use of steam were the only agents brought in aid of muscular effort for performing industrial processes, are, as we have seen, generated by solar heat. And the inanimate power that now, to so vast an extent, supplements human labour, is similarly derived. Sir John Herschel was the first to recognize the truth that the force impelling a locomotive, originally emanated from the Sun. Step by step we go back — from the motion of the piston to the evaporation of the water; thence to the heat evolved during the burning of coal; thence to the assimilation of carbon by the plants of whose imbedded products coal consists; thence to the carbon di-oxide from which their carbon was obtained; and thence to the rays of light which effected the de-oxidation. Solar forces millions of years ago expended on the Earth's vegetation, and since locked up in deep-seated strata, now smelt the metals required for our machines, turn the lathes by which the machines are shaped, work them when put together, and distribute the fabrics they produce. And since economy of labour makes possible a larger population, gives a surplus of human power that would else be absorbed in manual occupations, and thus facilitates the development of higher kinds of activity; these social forces which are directly correlated with Physical forces anciently derived from the Sun, are only less important than those of which the correlates are the vital forces recently derived from it.

§73. Many who admit that among physical phenomena at large, transformation of forces is now established, will probably say that inquiry has not yet gone far enough to enable us to assert equivalence. And in respect of the forces classed as vital, mental, and social, the evidence assigned they will consider by no means conclusive even of transformation, much less of equivalence.

But the universal truth above followed out under its various aspects, is a corollary from the persistence of force. From the proposition that force can neither come into existence nor cease to exist, the several foregoing conclusions inevitably follow. Each manifestation of force can be interpreted only as the effect of some antecedent force; no matter whether it be an inorganic action, an animal movement, a thought, or a feeling. Either bodily and mental energies, as well as inorganic ones, are quantitatively correlated to certain energies expended in their production, and to certain other energies which they initiate; or else nothing must become something and something must become nothing. The alternatives are, to deny the persistence of force, or to admit that from given amounts of antecedent energies neither more nor less than certain physical and psychical changes can result. This corollary cannot indeed be made more certain by accumulating illustrations. Whatever proof of correlation and equivalence is reached by experimental inquiry, is based on measurement of the forces expended and the forces produced. But, as was shown in the last chapter, any such process implies the use of some unit of force which is assumed to remain constant; and its constancy can be assumed only as being a corollary from the persistence of force. How then can any reasoning based on this corollary, prove the equally direct corollary that when a given quantity of force ceases to exist under one form, an equal quantity must come into existence under some other form or forms?

"What, then," it may be asked, "is the use of investigations by which transformations and equivalence of forces is sought to be inductively established? If the correlation cannot be made more certain by them than it is already does not their uselessness necessarily follow?" No. They are of value as disclosing the many particular implications which the general truth does not specify. They are of value as teaching us how much of one mode of force is the equivalent of so much of another mode. They are of value as detecting under what conditions each metamorphosis occurs. And they are of value as leading us to inquire in what shape the remnant of force has escaped, when the apparent results are not equivalent to the cause.

Chapter 9

The Direction of Motion

§74. The Absolute Cause of changes, no matter what may be their special natures, is not less incomprehensible in respect of the unity or duality of its action, than in all other respects. Are phenomena due to the variously-conditioned workings of a single force, or are they due to the conflict of two forces? Whether everything is explicable on the hypothesis of universal pressure, whence so-called tension results differentially from inequalities of pressure; or whether things are to be explained on the hypothesis of universal tension, from which pressure is a differential result; or whether, as most physicists hold, pressure and tension everywhere co-exist; are questions which it is impossible to settle. Each of these three suppositions makes the facts comprehensible, only by postulating an inconceivability. To assume a universal pressure, confessedly requires us to assume an infinite plenum — an unlimited space full of something which is everywhere pressed by something beyond; and this assumption cannot be mentally realized. That universal tension is the agency, is an idea open to a parallel and equally fatal objection. And verbally intelligible as is the proposition that pressure and tension everywhere co-exist, yet we cannot truly represent to ourselves one ultimate unit of matter as drawing another while resisting it.

Nevertheless, this last belief we are compelled to entertain. Matter cannot be conceived except as manifesting forces of attraction and repulsion. In our consciousness, Body is distinguished from Space by its opposition to our muscular energies; and this opposition we feel under the twofold form of a cohesion which hinders our efforts to rend, and a resistance which hinders our efforts to compress. Without resistance there can be nothing but empty extension. Without cohesion there can be no resistance. Probably this conception of antagonistic forces originates from the antagonism of our flexor and extensor muscles. But be this as it may we are obliged to think of all objects as made up of parts that attract and repel one another, since this is the form of our experience of all objects.

By a higher abstraction results the conception of attractive and repulsive forces pervading space. We cannot dissociate force from occupied extension, or occupied extension from force, because we have never an immediate consciousness of either in the absence of the other. Nevertheless, we have abundant proof that force is exercised through what appears to our senses a vacuity. Mentally to represent this exercise, we are hence obliged to fill the apparent vacuity with a species of matter — an ethereal medium. The constitution we assign to this ethereal medium, however, is necessarily an abstract of the impressions received from tangible bodies. The opposition to pressure which a tangible body offers to us, is not shown in one direction only, but in all directions; and so likewise is its tenacity. Suppose countless lines radiating from its centre, and it resists along each of these lines and coheres along each of these lines. Hence the constitution of those ultimate units through the instrumentality of which phenomena are interpreted. Be they molecules of ponderable matter or molecules of ether, the properties we conceive them to possess are nothing else than these perceptible properties idealized. Centres of force attracting and repelling one another in all directions, are simply insensible portions of matter having the endowments common to sensible portions of matter — endowments of which we cannot by any mental effort divest them. In brief, they are the invariable elements of the conception of matter, abstracted from its variable elements — size, form, quality, etc. And so to interpret manifestations of force which cannot be tactually experienced, we use the terms of thought supplied by our tactual experiences, and this for the sufficient reason that we must use these or none.

It needs scarcely be said that these universally co-existent forces of attraction and repulsion, must not be taken as realities, but as our symbols of the reality. They are the forms under which the workings of the Unknowable are cognizable by us — modes of the Unconditioned as presented under the conditions of our consciousness. How these ideas st and related to the absolute truth we cannot know, but we may unreservedly surrender ourselves to them as relatively true, and may proceed to evolve a series of deductions having a like relative truth.

§75. Universally co-existent forces of attraction and repulsion, imply certain laws of direction of all movement. Where attractive forces alone are concerned, or rather are alone appreciable, movement takes place in the direction of their resultant; which may, in a sense, be called the line of greatest traction. Where repulsive forces alone are concerned, or rather are alone appreciable, movement takes place along their resultant; which is usually known as the line of least resistance. And where both attractive and repulsive forces are concerned, and are appreciable, movement takes place along the resultant of the tractions and resistances. Strictly speaking this last is the sole law; since, by the hypothesis, both forces are everywhere in action. But very frequently the one kind of force is so immensely in excess, that the effect of the other kind may be left out of consideration. Practically, we may say that a body falling to the Earth follows the line of greatest traction; since, though the resistance of the air must, if the body be irregular, cause some divergence from this line (quite perceptible with feathers and leaves), yet, ordinarily the divergence is so slight that we may disregard it. In the same manner though the courses taken by steam from an exploding boiler, differ somewhat from those which it would take were gravitation out of the question; yet, as gravitation affects its courses only infinitesimally, we are justified in saying that the escaping steam goes along lines of least resistance. Motion, then, always follows the line of greatest traction, or the line of least resistance, or the resultant of the two; and though the last is alone strictly true, the others are in many cases sufficiently near the truth for practical purposes.

Motion set up in any direction is itself a cause of further motion in that direction, since it is the manifestation of a surplus force in that direction. This holds equally with the transit of matter through space, the transit of matter through matter, and the transit through matter of any kind of vibration. In the case of matter moving through space, this principle is expressed in the law of inertia — a law which all the calculations of physical astronomy assume. In the case of matter moving through matter, we trace the same truth under the familiar experience that any breach made by one solid through another, or any channel formed by a fluid through a solid, becomes a route along which, other things equal, subsequent movements of like nature most readily take place. And in the case of motion passing through matter under the form of an impulse communicated from part to part, the facts of magnetization appear to imply that the establishment of undulations along certain lines, determines their continuance along those lines.

It further follows from the conditions, that the direction of movement can rarely if ever be perfectly straight. For matter in motion to pursue continuously the exact line in which it sets out, the forces of attraction and repulsion must be symmetrically disposed around its path; and the chances against this are infinitely great. It may be added that in proportion as the forces at work are numerous and varied, the line a moving body describes is necessarily complex: witness the contrast between the flight of an arrow and the gyrations of a stick tossed about by breakers.

As a step towards unification of knowledge, we have now to trace these general laws throughout the various orders of changes which the Cosmos exhibits.

§76. In the Solar System the principles thus briefly summarized are every instant exemplified. Each planet aid satellite has a momentum which would, if acting alone, carry it forward in the direction it is at any instant pursuing — a momentum which would make a straight line its line of least resistance. Each planet and satellite, however, is drawn by a force which, if it acted alone, would take it in a straight line towards its primary. And the resultant of these two forces is that curve which it describes — a curve consequent on the unsymmetrical distribution of the forces around. When more closely examined, its path supplies further illustrations. For it is not an exact circle or ellipse; which it would be were the tangential and centripetal forces the only ones concerned. Adjacent members of the Solar System, ever varying in their relative positions, cause perturbations; that is, slight divergences from that circle or ellipse which the two chief forces would produce. These perturbations severally show us in minor degrees, how the line of movement is the resultant of all the forces engaged; and how this line becomes more complicated in proportion as the forces are multiplied.

If instead of the motions of the planets and satellites as wholes, we consider the motions of their parts, we meet with comparatively complex illustrations. Every portion of the Earth's substance in its daily rotation; describes a curve which is in the main a resultant of that resistance which checks its nearer approach to the centre of gravity, that momentum which would carry it off at a tangent, and those forces of gravitation and cohesion which keep it from being so carried off. When with this axial motion is contemplated the orbital motion, the course of each part is seen to be a much more involved one. And we find it to have a still greater complication on taking into account that lunar attraction which mainly produces the tides and the precession of the equinoxes.

§77. We come next to terrestrial changes: present ones as observed, and past ones as inferred by geologists. Let us set out with the unceasing movements in the Earth's atmosphere; descend to the slow alterations in progress on its surface; and then to the still slower ones going on beneath.

Masses of air absorbing heat from surfaces warmed by the Sun, expand, and ascend: the resistance being less than the resistance to lateral movement. Adjacent atmospheric masses, moving in the directions of the diminished resistance, displace the expanded air. When, again, by the ascent of heated air from great tracts like the torrid zone, there is produced at the upper surface of the atmosphere a protuberance — when the air forming this protuberance overflows laterally towards the poles; it does so because, while the tractive force of the Earth is nearly the same, the lateral resistance is diminished. And throughout the course of each current thus generated, as well as throughout the course of each counter-current flowing into the space vacated, the direction is always the resultant of the Earth's tractive force and the resistance offered by the surrounding masses of air: modified only by conflict with other currents similarly generated, and by collision with prominences on the Earth's crust. The movements of water, in both its gaseous and liquid states, furnish further examples. Evaporation is the escape of particles of water in the direction of least resistance; and as the resistance (which is due to gaseous pressure) diminishes, the evaporation increases. On the other hand condensation, which takes place when any portion of atmospheric vapour has its temperature much lowered, may be interpreted as a diminution of the mutual pressure among the condensing particles, while the pressure of surrounding particles remains the same; and so is a motion taking place in the direction of lessened resistance. In the course followed by the resulting raindrops, we have one of the simplest instances of the joint effect of the two antagonist forces. The Earth's attraction, and the resistance of atmospheric currents ever varying in direction and intensity, give as their resultants, lines which incline to the horizon in countless different degrees and undergo perpetual variations. In the course the rain-drops take while trickling over the surface, in every rill, in every larger stream, and in every river, we see them descending as straight as the antagonism of surrounding objects permits. So far from a cascade furnishing an exception, it furnishes but another illustration. For though all solid obstacles to a vertical fall of the water are removed, yet the water's horizontal momentum is an obstacle; and the parabola in which the stream leaps from the projecting ledge is generated by the combined gravitation and momentum.

The Earth's solid crust undergoes changes which supply another group of illustrations. The denudation of lands and the depositing of the removed sediment in new strata at the bottoms of seas and lakes, is a process throughout which motion is obviously determined in the same way as is that of the water effecting the transport. Again, though we have no direct inductive proof that the forces classed as igneous expend themselves along lines of least resistance, yet what little we know of them is in harmony with the belief that they do so. Earthquakes continually revisit the same localities, and special tracts undergo for long periods together successive elevations or subsidences: facts which imply that already-fractured portions of the Earth's crust are those most prone to yield under the pressure caused by further contractions. The distribution of volcanoes along certain lines, as well as the frequent recurrence of eruptions from the same vents, are facts of like meaning.

§78. That organic growth takes place in the direction of least resistance, is a proposition set forth and illustrated by Mr. James Hinton, in the Medico-Chirurgical Review for October, 1858. After detailing a few of the early observations which led him to this generalization, he formu1ates it thus: —

"Organic form is the result of motion." "Motion takes the direction of least resistance." "Therefore organic form is the result of motion in the direction of least resistance."

After an elucidation and defence of this position, Mr. Hinton proceeds to interpret, in conformity with it, sundry phenomena of development. Shaking of plants, he says: —

"The formation of the root furnishes a beautiful illustration of the law of least resistance, for it grows by insinuating itself, cell by cell, through the interstices of the soil; it is by such minute additions that it increases, winding and twisting whithersoever the obstacles it meets in its path determine, and growing there most, where the nutritive materials are added to it most abundantly. As we look on the roots of a mighty tree, it appears to us as if they had forced themselves with giant violence into the solid earth. But it is not so; they were led on gently cell added to cell, softly as the dews descended, and the loosened earth made way. Once formed, indeed, they expand with an enormous power, but the spongy condition of the growing radicles utterly forbids the supposition that they are forced into the earth. Is it not probable, indeed, that the enlargement of the roots already formed may crack the surrounding soil, and help to make the interstices into which the new rootlets grow? * * *

"Throughout almost the whole of organic nature the spiral form is more or less distinctly marked. Now, motion under resistance takes a spiral direction, be seen by the motion of a body rising or falling through water. A bubble rising rapidly in water describes a spiral closely resembling a corkscrew, and a body of moderate specific gravity dropped into water may be seen to fall in a curved direction, the spiral tendency of which may be distinctly observed. * * * In this prevailing spiral form of organic bodies, therefore, it appears to me, that there is presented a strong prima facie case for the view I have maintained. * * * The spiral form of the branches of many trees is very apparent, and the universally spiral arrangement of the leaves around the stem of plants needs only to be referred to. * * * The heart commences as a spiral turn, and in its perfect form a manifest spiral may be traced through the left ventricle, right ventricle, right auricle, left auricle, and appendix. And what is the spiral turn in which the heart commences but a necessary result of the lengthening, under a limit, of the cellular mass of which it then consists? * * *

"Every one must have noticed the peculiar curling up of the young leaves of the common fern. The appearance is as if the leaf were rolled up, but in truth this form is merely a phenomenon of growth. The curvature results from the increase of the leaf, it is only another form of the wrinkling up, or turning at right angles by extension under limit.

"The rolling up or imbrication of the petals in many flower-buds is a similar thing; at an early period the small petals may be seen lying side by side; afterwards growing within the capsule, they become folded round one another. * * *

"If a flower-bud be opened at a sufficiently early period, the stamens will be found as if moulded in the cavity between the pistil and the corolla, which cavity the anthers exactly fill; the stalks lengthen at an after period. I have noticed also in a few instances, that in those flowers in which the petals are imbricated, or twisted together, the pistil is tapering as growing up between the petals; in some flowers which have the petals so arranged in the bud as to form a dome (as the hawthorn; e.g.), the pistil is flattened at the apex, and in the bud occupies a space precisely limited by the stamens below, and the enclosing petals above and at the sides. I have not, however, satisfied myself that this holds good in all cases."

Without endorsing all Mr. Hinton's illustrations, his conclusion may be accepted as a large instalment of the truth. But in the case of organic growth, as in all other cases, the line of movement is in strictness the resultant of tractive and resistant forces; and the tractive forces here form so considerable an element that the formula is not complete without them. The shapes of plants are manifestly modified by gravitation. The direction of each branch is not what it would have been in the absence of the pull exercised by the Earth; and every flower and leaf is somewhat altered in the course of development by the weight of its parts. Though in animals such effects are less conspicuous, yet the instances in which flexible organs have their directions in great measure determined by gravity, justify the assertion that throughout the whole organism the forms of parts must be affected by this force.

The organic movements which constitute growth, are not, however, the only organic movements to be interpreted. There are also those which constitute function; and throughout these the same general principles are discernible. That the vessels and ducts along which blood, lymph, bile, and all the secretions, find their ways, are channels of least resistance, is an illustration almost too conspicuous to be named. Less conspicuous, however, is the truth that the currents set ting along these vessels are affected by the tractive force of the Earth; witness varicose veins; witness the relief to an inflamed part obtained by raising it; witness the congestion of head and face produced by stooping. And in the facts that dropsy in the legs gets greater by day and decreases at night, while, conversely that oedematous fullness under the eyes common in debility, grows worse during the hours of reclining and decreases after getting up, we see how the transudation of liquid through the walls of the capillaries, varies according as change of position changes the effect of gravity in different parts of the body.

It may be well just to note the bearing of the principle on the development of species. From a dynamic point of view, "natural selection" implies structural changes along lines of least resistance. The multiplication of any kind of plant or animal in localities that are favourable to it, is a growth where the antagonistic forces are less than elsewhere. And the preservation of varieties which succeed better than their allies in coping with surrounding conditions, is the continuance of vital movements in those directions where the obstacles to them are most eluded.

§79. Throughout mental phenomena the law enunciated is not readily established. In a large part of them, as those of thought and emotion, there is no perceptible movement. Even in sensation and action, which show us in one part of the body an effect produced by a force applied to another part, the intermediate movement is inferential only. Some suggestions may be made however.

A stimulation implies a force added to, or evolved in, that part of the organism which is its seat; while a mechanical movement implies an expenditure or loss of force in that part of the organism which is its seat: implying some tension of molecular state between the two localities. Hence if, in the life of a minute animal, there are circumstances involving that a stimulation in one particular place is habitually followed by a contraction in another particular place — if there is thus a repeated motion through some line of least resistance between these places; what must be the result as respects the line? If this line — this channel — is affected by the discharge — if the obstructive action of the tissues traversed, involves any reaction. upon them, deducting from their obstructive power; then a subsequent motion between these two points will meet with less resistance along this channel than the previous motion met with, and will consequently take this channel still more decidedly. Every repetition will further diminish the resistance offered; and thus will gradually be formed a permanent line of communication, differing greatly from the surrounding tissue in respect of the ease with which force traverses it. Hence in small creatures may result rudimentary nervous connexions. Only an adumbration of nervous processes thus hinted as conforming to the general law, is here possible. But the effects of associations between impressions and motions as seen in habits, all yield illustrations. In knitting, in reading aloud, in the performance of the skilled pianist who talks while he plays, we have examples of the way in which channels of nervous communication are eventually made so permeable by perpetual discharges along them as to bring about a state almost automatic or reflex: illustrating at once the fact that molecular motion follows lines of least resistance, and the fact that motion along such lines, by diminishing the resistance, further facilitates the motion. Though qualifications arising in the same manner as those indicated in the last chapter complicate these nervo-motor processes in ways which cannot here be followed, they do not conflict with the law set forth. Moreover they are congruous with the principle that in proportion to the frequency with which any external connexion of phenomena is experienced, will be the strength of the answering internal connexion of nervous states. In this way will arise all degrees of cohesion among nervous states, as there are all degrees of commonness among the surrounding co-existences and sequences that generate them. Whence must result a general correspondence between associated ideas and associated actions in the environment.*

<* This paragraph is a re-statement, somewhat amplified, of an idea set forth in the Medico-Chirurgical Review for January, 1859 (pp. 189 and 190); and contains the germ of the intended fifth part of the Principles of Psychology, which was withheld for reasons given in the preface to that work.>

The relation between emotions and actions may be similarly construed. Observe what happens with emotions which are undirected by volitions. As was pointed out in the last chapter, there result movements of the involuntary and voluntary muscles, that are great in proportion as the emotions are strong. It remains here to add that the order in which these muscles are affected conforms to the principle. A pleasurable or painful feeling of but slight intensity does little more than increase the action of the heart. Why? For the reason that the relation between nervous excitement and cardiac contraction, being common to every species of feeling, is the one of most frequent repetition; that hence the nervous connexion offering the least resistance to a discharge, is the one along which a feeble force produces motion. A stronger sentiment affects not only the heart but the muscles of the face, and especially those around the mouth. Here the like explanation applies; since these muscles, being both comparatively small and, for purposes of speech, perpetually used, offer less resistance than other voluntary muscles to the nervo-motor forces. By a further increase of emotion the respiratory and vocal muscles become perceptibly excited. Finally, under violent passion, the muscles of the trunk and limbs are strongly contracted. The single instance of laughter, which is an undirected discharge of feeling that affects first the muscles round the mouth, then those of the vocal and respiratory apparatus, then those of the limbs, and then those of the spine; suffices to show that when no special route is opened for it, a force evolved in the nervous centres produces motion along channels which offer the least resistance, and if is too great to escape by these, produces motion along channels offering successively greater resistance.*

<* For details see a paper on "The Physiology of Laughter," published in Macmillan's Magazine for March, 1860, and reprinted in Essays, vol. II.>

Probably it will be thought impossible to extend this reasoning so as to include voluntary acts. Yet we are not without evidence that the transition from special desires to special muscular motions, conforms to the same principle. The mental antecedents of a voluntary movement, are such as temporarily make the line through which this movement is initiated, the line of least resistance. For a volition, suggested as it is by some previous thought joined with it by associations that determine the transition, is itself a representation of the movements which are willed, and of their sequences. But to represent in consciousness certain of our own movements, is partially to arouse the sensations accompanying such movements, inclusive of those of muscular tension — is partially to excite the appropriate motor-nerves and all the other nerves implicated. That is to say, the volition is itself an incipient discharge along a line which previous experiences have rendered a line of least resistance. And the passing of volition into action is simply a completion of the discharge.

One corollary must be noted; namely that the particular set of movements by which an object of desire is reached, are usually movements implying the smallest total of forces to be overcome. As the motion initiated by each feeling takes the line of least resistance, it is inferable that a group of feelings constituting a more or less complex desire will initiate motions along a series of lines of least resistance; that is, the desired end will be achieved with the smallest effort. Doubtless through want of knowledge or want of skill or want of resolution to make immediate exertion, a man often takes the more laborious of two courses. But it remains true that relatively to his mental state at the time, his course is the easiest to him — the one least resisted by the aggregate of his feelings.

§80. As with individual men so is it with aggregations of men. Social changes take directions that are due to the joint actions of citizens, determined as are those of all other changes wrought by composition of forces.

Thus when we note the direction of a nation's growth, we find it to be that in which the aggregate of opposing forces is least. Its units have energies to be expended in self-maintenance and reproduction. These energies are met by various antagonistic energies — those of geologic origin, those of climate, of wild animals, of other human races with whom there is enmity or competition. And the tracts the society spreads over, are those in which there is the smallest total of antagonisms while they yield the best supply of food and other materials which further the genesis of energies. For these reasons it happens that fertile valleys where water and vegetal products abound, are early peopled. Sea-shores, too, supplying much easily-gathered food, are lines along which mankind have commonly spread. The general fact that, so far as we can judge from the traces left by them, large societies first appeared in those warm regions where the fruits of the earth are obtainable with comparatively little exertion, and where the cost of maintaining bodily heat is but slight, is a fact of like meaning. And to these instances may be added the allied one daily furnished by emigration, which we see going on towards countries presenting the fewest obstacles to the self-preservation of individuals, and therefore to national growth. Similarly with that resistance to the movements of a society which neighbouring societies offer. Each of the tribes or nations inhabiting any region, increases in numbers until it outgrows its means of subsistence. In each there is thus a force ever pressing outwards on to adjacent areas — a force antagonized by like forces in the tribes or nations occupying those areas. And the wars that result — the conquests of weaker tribes or nations, and the overrunning of their territories by the victors, are instances of social movements taking place in the directions of least resistance. Nor do the conquered peoples, when they escape extermination or enslavement, fail to show us movements which are similarly determined. For, migrating as they do to less fertile regions — taking refuge in deserts or among mountains — moving in directions where the resistances to social growth are comparatively great; they still do this only under an excess of pressure in all other directions: the physical obstacles to self-preservation they encounter; being really less than the obstacles offered by the enemies from whom they fly.

Internal social movements also may be thus interpreted. Localities naturally fitted for producing particular commodities — that is, localities in which such commodities are got at the least cost of energy — that is, localities in which the desires for these commodities meet with the least resistance; become localities devoted to the obtainment of these commodities. Where soil and climate render wheat a profitable crop, or a crop from which the greatest amount of life-sustaining power is gained by a given quantity of effort, the growth of wheat becomes a dominant industry. Where wheat cannot be economically produced, oats, or rye, or maize, or potatoes, or rice, is the agricultural staple. Along sea-shores men support themselves with least effort by catching fish, and hence fishing becomes the occupation. And in places which are rich in coal or metallic ores, the population, finding that labour expended in raising these materials brings a larger return of food and clothing than when otherwise expended, becomes a population of miners. This last instance introduces us to the phenomena of exchange, which equally illustrate the general law. For the practice of barter begins as soon as it facilitates the fulfilment of men's desires, by diminishing the exertion needed to reach the objects of those desires. When instead of growing his own corn, weaving his own cloth, sewing his own shoes, each man began to confine himself to farming, or weaving, or shoemaking; it was because each found it more laborious to make everything he wanted, than to make a great quantity of one thing and barter the surplus for other things. Moreover, in deciding what commodity to produce, each citizen was, as he is at the present day, guided in the same manner. In choosing those forms of activity which their special circumstances and special faculties dictate, the social units severally move towards the objects of their desires in the directions which present to them the fewest obstacles. The process of transfer which commerce presupposes, supplies another series of examples. So long as the forces to be overcome in procuring any necessary of life in the district where it is consumed, are less than the forces to be overcome in procuring it from an adjacent district, exchange does not take place. But when the adjacent district produces it with an economy that is not outbalanced by cost of transit — when the distance is so small and the route so easy that the labour of conveyance plus the labour of production is less than the labour of production in the consuming district, transfer commences. Movement in the direction of least resistance is also seen in the establishment of the channels along which intercourse takes place. At the outset, when goods are carried on the backs of men and horses, the paths chosen are those which combine shortness with levelness and freedom from obstacles — those which are achieved with the smallest exertion. And in the subsequent formation of each highway, the course taken is that which deviates horizontally from a straight line so far only as is needful to avoid vertical deviations entailing greater labour in draught. The smallest total of obstructive forces determines the route, even in seemingly exceptional cases; as where a detour is made to avoid the opposition of a landowner. All subsequent improvements, ending in macadamized roads, canals, and railways, which reduce the antagonism of friction and gravity to a minimum, exemplify the same truth. After there comes to be a choice of roads between one point and another, we still see that the road chosen is that along which the cost of transit is the least: cost being the measure of resistance. When there arises a marked localization of industries, the relative growths of the populations devoted to them may be interpreted on the same principle. The influx of people to each industrial centre is determined by the payment for labour — that is, by the quantity of commodities which a given amount of effort will obtain. To say that artisans flock to places where, in consequence of facilities for production, an extra proportion of produce can be given in the shape of wages, is to say that they flock to places where there are the smallest obstacles to the Support of themselves and families; and so growth of the social organism takes place where the resistance is least.

Nor is the law less clearly to be traced in those functional changes daily going on. The flow of capital into businesses yielding the largest returns, the buying in the cheapest market and selling in the dearest, the introduction of more economical modes of manufacture, the development of better agencies for distribution, exhibit movements taking place in directions where they are met by the smallest totals of opposing forces. For if we analyze each of these changes — if instead of interest on capital we read surplus of products which remains after maintenance of labourers — if we thus interpret large interest or large surplus to imply labour expended with the greatest results — and if labour expended with the greatest results means muscular action so directed as to evade obstacles as far as possible; we see that all these commercial phenomena imply complicated motions set up along lines of least resistance.

Social movements of these various orders severally conform to the two derivative principles named at the outset. In the first place we see that, once set up in given directions, such movements, like all others, tend to produce continuance in these directions. A commercial mania or panic, a current of commodities, a social custom, a political agitation, or a popular delusion, maintains its course long after its original cause has ceased, and requires antagonistic forces to arrest it. In the second place it is to be noted that in proportion to the complexity of social forces is the tortuousness of social movements. The involved series of various processes through which a man is returned to Parliament, or through which afterwards, by an Act he finally gets passed, certain doings of his fellow-citizens are changed, show this.

§81. And now of the general truth above set forth what is our ultimate evidence? Must we accept it simply as an empirical generalization? or may it be established as a corollary from a still deeper truth? The reader will anticipate the answer.

Suppose several tractive forces, variously directed, to be acting on a given body. By what is known as the composition of forces, there may be found for any two of these, a single force of such amount and direction as to produce on the body an exactly equal effect. Such a resultant force, as it is called, may be found for any pair of forces throughout the group. Similarly, for any pair of resultants a single resultant may be found. And by repeating this course, all of them may be reduced to two. If these two are equal and opposite — that is, if there is no line of greatest traction, motion does not arise. If they are opposite but not equal, motion arises in the direction of the greater. If they are neither equal nor opposite, motion arises in the direction of their resultant. For in either of these cases there is an unantagonized force in one direction. And this residuary force must move the body in the direction in which it is acting. To assert the contrary is to assert that a force can be expended without effect; and this involves a denial of the persistence of force. If in place of tractions we take resistances, the argument equally holds; and it holds also where both tractions and resistances are concerned. Thus the law that motion follows the line of greatest traction, or the line of least resistance, or the resultant of the two, is a necessary deduction from that primordial truth which transcends proof.

Reduce the proposition to its simplest form, and its truth becomes still more obvious. Suppose two weights suspended over a pulley, or suppose two men pulling against each other. The heavier weight will descend, and the stronger man will draw the weaker towards him. If asked how we know which is the heavier weight or the stronger man, we can only reply that it is the one producing motion in the direction of its pull. But if of two opposing tractions we can know one as greater than the other only by the motion it generates in its own direction, then the assertion that motion occurs in the direction of greatest traction is a truism. When, going a step further back, we seek a warrant for the assumption that of the two conflicting forces, the one which produces motion in its own direction is the greatest, we find no other than the consciousness that such part of the greater force as is unneutralized by the lesser, must produce its effect — the consciousness that this residuary force cannot disappear, but must manifest itself in some equivalent change — the consciousness that force is persistent. Here too, as before, it may be remarked that no number of varied illustrations, like those of which this chapter mainly consists, can give greater certainty to the conclusion thus immediately drawn from the ultimate datum of consciousness. For in all cases, as in the simple ones just given, we can identify the greatest force only by the resulting motion.

From this same primordial truth, too, may be deduced the principle that motion once set up along any line, becomes itself a cause of subsequent motion along that line. The mechanical axiom that, if left to itself, matter moving in any direction will continue in that direction with undiminished velocity, is but an indirect assertion of the persistence of that kind of force called energy; since it is an assertion that the energy manifested in the transfer of a body along a certain length of a certain line in a certain time, cannot disappear without producing some equal manifestation: a manifestation which, in the absence of conflicting forces, must be a further transfer in the same direction at the same velocity. In the case of matter traversing matter a like inference is necessitated. Here however the actions are complicated. A liquid that follows a certain channel through or over a solid, as water along the Earth's surface, loses part of its motion in the shape of heat, through friction and collision with the matters forming its bed. A further amount may be absorbed in overcoming the forces it liberates; as when it loosens a mass which falls into its channel. But after these deductions, any further deduction from the energy embodied in the motion of the water, is at the expense of a reaction on the channel which diminishes its obstructive power: such reaction being shown in the motion acquired by the detached portions carried away. The cutting out of river-courses perpetually illustrates this truth. Still more involved is the case of motion passing through matter by impulse from part to part; as a nervous discharge through animal tissue. There are conceivable anomalies. Some chemical change wrought along the route traversed, may render it less fit than before for conveying a current. Or some obstructive form of force may be generated; as in metals, the conducting power of which is, for the time, decreased by the heat which the electric current produces. The real question is, however, what structural modification, if any, is produced throughout the matter traversed, apart from incidental disturbing forces — apart from everything but the necessary resistance of the matter: that, namely which results from the inertia of its units. If we confine our attention to that part of the motion which, escaping transformation, continues its course, then the persistence of force necessitates that as much of it as is taken up in changing the positions of the units, must leave these by so much less able to obstruct subsequent motion in the same direction.

Thus in all the changes displayed by the Solar System, in all those which are going on in the Earth's crust, in all processes of organic development and function, in all mental actions and the effects they work on the body, and in all modifications of structure and activity in societies, the implied movements are of necessity determined in the manner above set forth. The truth set forth holds not only of one class, or of some classes, of phenomena, but it is among those universal truths by which our knowledge of phenomena in general is unified.

Chapter 10

The Rhythm of Motion

§82. When the pennant of a vessel lying becalmed shows the coming breeze, it does so by gentle undulations which travel from its fixed to its free end. Presently the sails begin to flap; and their blows against the mast increase in rapidity as the breeze rises. Even when, being fully bellied out, they are in great part steadied by the strain of the yards and cordage, their free edges tremble with each stronger gust. And should there come a gale, the jar that is felt on laying hold of the shrouds shows that the rigging vibrates; while the whistle of the wind proves that in it, also, rapid undulations are generated. Ashore the conflict between the current of air and the things it meets results in a like rhythmical action. The leaves all shiver in the blast; each branch oscillates; and every exposed tree sways to and fro. The blades of grass and dried bents in the meadows, and still better the stalks in the neighbouring corn-fields, exhibit the same rising and falling movements. Nor do the more stable objects fail to do the like, though in a less manifest fashion; as witness the shudder that may be felt throughout a house during the paroxysms of a violent storm. Streams of water produce in opposing objects the same general effects as do streams of air. Submerged weeds growing in the middle of a brook, undulate from end to end. Branches brought down by the last flood, and left entangled at the bottom where the current is rapid, are thrown into a state of up and down movement that is slow or quick t proportion as they are large or small; and where, as in great rivers like the Mississippi, whole trees are thus held, the name "sawyers," by which they are locally known, sufficiently describes the rhythm produced in them. Note, again, the effect of the antagonism between the current and its channel. In shallow places, where the action of the bottom on the water flowing over it is visible, we see a ripple produced — a series of undulations. If we study the action and reaction going on between the moving fluid and its banks, we still find the principle illustrated, though in a different way. For in every rivulet, as in the mapped-out course of every great river, the bends of the stream from side to side throughout its tortuous course constitute a lateral undulation — an undulation so inevitable that even an artificially-straightened channel is eventually changed into a serpentine one. Kindred phenomena may be observed when the water is stationary and the solid matter moving. A stick drawn laterally through the water with much force, proves by the throb which it communicates to the hand that it is in a state of vibration. Even where the moving body is massive, it only requires that great force should be applied to get a sensible effect of like kind: instance the screw of a screw-steamer [of the primitive type], which instead of a smooth rotation falls into a rapid rhythm that sends a tremor through the whole vessel. The sound produced when a bow is drawn over a violin-string, shows us vibrations accompanying the movement of a solid. In lathes and planing machines, the attempt to take off a thick shaving causes a violent jar of the whole apparatus, and the production of a series of waves on the iron or wood that is cut. Every boy in scraping his slate-pencil finds it scarcely possible to help making a ridged surface. If you roll a ball along the ground or over the ice, there is always more or less up and down movement — a movement that is visible while the velocity is considerable, but becomes too small and rapid to be seen by the unaided eye as the velocity diminishes. However smooth the rails, and however perfectly built the carriages, a railway-train inevitably acquires oscillations, both lateral and vertical. Even where a moving mass is suddenly arrested by collision, the law is still illustrated; for both the body striking and the body struck are made to tremble; and trembling is rhythmical movement. Little as we habitually observe it, it is yet certain that the impulses our actions impress from moment to moment on surrounding objects, are propagated through them in vibrations. It needs but to look through a telescope of high power, placed on a table, to be convinced that each pulsation of the heart gives a jar to surrounding things. Motions of another order — those namely of the ethereal medium — teach us the same thing. Every fresh discovery confirms the hypothesis that light consists of undulations, and that the rays of heat have a like fundamental nature: their undulations differing from those of light only in their comparative lengths. Nor do the movements of electricity fail to furnish us with illustrations; though of a different order. The northern aurora may often be observed to pulsate with waves of greater brightness; and the electric discharge through a vacuum shows by its stratified appearance that the current is not uniform, but comes in gushes of greater and lesser intensity. Should it be said that there are some motions, as those of projectiles, which are not rhythmical, the reply is that the exception is apparent only, and that these motions would be rhythmical if they were not interrupted. It is common to assert that the trajectory of a cannon-ball is a parabola; and it is true that (omitting atmospheric resistance) the curve described differs so slightly from a parabola that it may practically be regarded as one. But, strictly speaking, it is a portion of an extremely eccentric ellipse, having the Earth's centre of gravity for its remoter focus; and but for its arrest by the substance of the Earth, the cannon-ball would travel round that focus and return to the point whence it started; again to repeat this slow rhythm. Indeed, while seeming to do the reverse, the discharge of a cannon furnishes one of the best illustrations of the principle enunciated. The explosion produces violent undulations in the surrounding air. The whizz of the shot, as it flies towards its mark, is due to another series of atmospheric undulations. And the eccentric movement round the Earth's centre, which the cannon-ball is beginning to perform, being checked by solid matter, is transformed into a rhythm of another order; namely, the vibration which the blow sends through neighbouring bodies.*

<* After having for some years supposed myself alone in the belief that all motion is rhythmical, I discovered that my friend Professor Tyndall also held this doctrine.>

Rhythm is very generally not simple but compound. There are usually at work various forces, causing undulations differing in rapidity; and hence besides the primary rhythms there arise secondary rhythms, produced by the periodic coincidence and opposition of the primary ones. Double, triple, and even quadruple rhythms, are thus generated. One of the simplest instances is afforded by what in acoustics are known as "beats": recurring intervals of sound and silence which are perceived when two notes of nearly the same pitch are struck together and which are due to the alternate correspondence and antagonism of the atmospheric waves. In like manner the phenomena due to what is called interference of light, result from the periodic agreement and disagreement of ethereal undulations — undulations which, by alternately intensifying and neutralizing each other, produce intervals of increased and diminished light. On the sea-shore may be noted sundry instances of compound rhythms. We have that of the tides, in which the daily rise and fall undergoes a fortnightly increase and decrease, due to the alternate coincidence and antagonism of the solar and lunar attractions. We have again that which is perpetually furnished by the surface of the sea: every large wave bearing smaller ones on its side, and these still smaller ones, with the result that each flake of foam, along with the portion of water bearing it, undergoes minor ascents and descents of several orders while it is being raised and lowered by the greater billows. A different and very interesting example of compound rhythm occurs in the little rills which, at low tide, run over the sand out of the shingle banks above. Where the channel of one of these is narrow and the stream runs strongly, the sand at the bottom is raised into a series of ridges corresponding to the ripple of the water. On watching, it will be seen that these ridges are being raised higher and the ripple growing stronger; until at length, the action becoming violent, the whole series of ridges is suddenly swept away, the stream runs smoothly, and the process commences afresh.

Rhythm results wherever there is a conflict of forces not in equilibrium. If the antagonist forces at any point are balanced, there is rest; and in the absence of motion there can of course be no rhythm. But if instead of a balance there is an excess of force in one direction — if, as necessarily follows, motion is set up in that direction; then for the motion to continue uniformly in that direction, the moving matter must, notwithstanding its unceasing change of place, present unchanging relations to the sources of force by which its motion is produced and opposed. This however is impossible. Every further transfer through space, by altering the ratio between the forces concerned, must prevent uniformity of movement. And if the movement cannot be uniform, then (save where it is destroyed, or rather transformed, as by the collision of two bodies travelling through space in a straight line towards each other) the only alternative is rhythm.

A secondary conclusion must not be omitted. In the last chapter we saw that motion is never absolutely rectilinear; and here it remains to add that, as a consequence, rhythm is necessarily incomplete. A truly rectilinear rhythm can arise only when the opposing forces are in exactly the same line, and the probabilities against this are infinitely great. To generate a perfectly circular rhythm, the two forces concerned must be exactly at right angles to each other, and must have exactly a certain ratio; and against this the probabilities are likewise infinitely great. All other proportions and directions of the two forces (omitting such as produce parabolas or hyperbolas) will produce an ellipse of greater or less eccentricity. And when, as always happens, above two forces are engaged, the curve described must be more complex, and cannot exactly repeat itself. So that throughout nature, this action and reaction of forces never brings about a complete return to a previous state. Where the movement is that of some aggregate whose units are partially independent, regularity is no longer traceable. And on the completion of any periodic change, the degree in which the state arrived at differs from the state departed from, is marked in proportion as the influences at work are numerous.

§83. That spiral arrangement common among the more structured nebulae, shows us the progressive establishment of revolution, and therefore of rhythm, in those remote spaces which the nebulae occupy. Double stars, moving in more or less eccentric orbits round common centres of gravity in periods some of which are now ascertained, exhibit settled rhythmical actions in distant parts of our Sidereal System.

The periodicities of the planets, satellites, and comets, familiar though they are, must be named as so many grand illustrations of this general law of movement. But besides the revolutions of these bodies in their orbits (all more or less eccentric), the Solar System presents us with rhythms of a less manifest and more complex kind. In each planet and satellite there is the revolution of the nodes — a slow change in the position of the orbit-plane, which after completing itself commences afresh. There is the gradual alteration in the length of the axis major of the orbit, and also of its eccentricity: both of which are rhythmical alike in the sense that they alternate between maxima and minima, and in the sense that the progress from one extreme to the other is not uniform, but is made with fluctuating velocity. Then, too, there is the revolution of the line of apsides round the heavens — not regularly, but through complex oscillations. And, further, we have changes in the directions of the planetary axes — that known as nutation, and that larger gyration which, in the case of the Earth, causes the precession of the equinoxes. These rhythms, already more or less compound, are compounded with one another. One of the simplest re-compoundings is seen in the secular acceleration and retardation of the moon, consequent on the varying eccentricity of the Earth's orbit. Another, having more important consequences, results from the changing direction of the axis of rotation in a planet having a decidedly eccentric orbit. The Earth furnishes the best example. During a certain long period it presents more of its northern than of its southern hemisphere to the Sun at the time of nearest approach to him; and then again, during a like period, presents more of its southern hemisphere than of its northern: a recurring coincidence which involves an epoch of 21,000 years, during which each hemisphere goes through a cycle of temperate seasons and seasons that are extreme in their heat and cold. Nor is this all. There is even a variation of this variation. For the summers and winters of the whole Earth become more or less strongly contrasted, as the eccentricity of its orbit increases or decreases. Hence during the increase of the eccentricity, the epochs of moderately contrasted seasons and epochs of strongly contrasted seasons, through which alternately each hemisphere passes, must grow more and more different in the degrees of their contrasts; and contrariwise during decrease of the eccentricity. So that in those movements of the Earth which determine the varying quantities of light and heat which any portion of it receives from the Sun, there goes on a quadruple rhythm: that causing day and night; that causing summer and winter; that causing the changing position of the axis at perihelion and aphelion, taking 21,000 years to complete; and that causing the variation of the orbit's eccentricity, gone through in millions of years.

§84. Those terrestrial processes directly depending on the solar heat, of course exhibit a rhythm that corresponds to the periodically changing amount of heat which each part of the Earth receives. The simplest, though the least obtrusive, instance is supplied by the magnetic variations. In these there is a diurnal increase and decrease, an annual increase and decrease, and a decennial increase and decrease: the latter answering to a period during which the solar spots become alternately abundant and scarce. And besides known variations there are probably others corresponding to the astronomical cycles just described. More obvious examples are furnished by the movements of the ocean and the atmosphere. Marine currents from the equator to the poles above, and from the poles to the equator beneath, show us an unceasing backward and forward motion throughout this vast mass of water — a motion varying in amount according to the seasons, and compounded with smaller like motions of local origin. The similarly-caused general currents in the air, have similar annual variations similarly modified. Irregular as they are in detail, we still see in the monsoons and other tropical atmospheric disturbances, or even in our autumn equinoctial gales and spring east winds, a periodicity sufficiently decided. Again, we have an alternation of times during which evaporation predominates with times during which condensation predominates; shown in the tropics by strongly marked rainy seasons and seasons of drought, and in the temperate zones by changes of which the periodicity is less definite. The diffusion and precipitation of water furnish us with examples of rhythm of a more rapid kind. During wet weather lasting over some weeks, the tendency to condense, though greater than the tendency to evaporate, does not show itself in continuous rain; but the period is made up of rainy days and days which are wholly or partially fair. Nor is it in this rude alteration only that the law is manifested. During any day throughout this wet weather a minor rhythm is often traceable; and especially so when the tendencies to evaporate and to condense are nearly balanced. Among mountains this minor rhythm and its causes may be studied to advantage. Moist winds, which do not precipitate their contained water in passing over the comparatively warm lowlands, lose so much heat when they reach the cold mountain peaks, that condensation rapidly takes place. Water, however, in passing from the gaseous to the liquid state, gives out heat; and therefore the resulting clouds are warmer than the air that precipitates them, and much warmer than the high rocky surfaces round which they fold themselves. Hence in the course of the storm, these high rocky surfaces are raised in temperature, partly by radiation from the enwrapping cloud, partly by contact of the falling rain-drops. Consequently they no longer lower so much the temperature of the air passing over them, and cease to precipitate its contained water. The clouds break; the sky begins to clear; and a gleam of sunshine promises that the day is going to be fine. But the small supply of heat which the cold mountains' tops have received, is soon lost: especially when partial dispersion of the clouds permits radiation into space. Very soon, therefore, these elevated surfaces, becoming as cold as at first, begin again to condense the vapour in the air above, and there comes another storm, followed by the same effects as before. In lower lands this action and reaction is less conspicuous, because the contrast of temperatures is less marked. Even here, however, it may be traced, not only on showery days, but on days of continuous rain; for in these we do not see uniformity: always there are fits of harder and gentler rain.

Of course these meteorologic rhythms involve corresponding rhythms in the changes wrought by wind and water on the Earth's surface. Variations in the quantities of sediment brought down by rivers that rise and fall with the seasons, must cause variations in the resulting strata — alternations of colour or quality in the successive laminae. Beds formed from the detritus of shores worn down and carried away by the waves, must similarly show periodic differences answering to the periodic winds of the locality. In so far as frost influences the rate of denudation, its recurrence is a factor in the rhythm of sedimentary deposits. And the geological changes produced by glaciers must similarly have their alternating periods of greater and less intensity.

There is some evidence that modifications in the Earth's crust due to igneous action have an indefinite periodicity. Volcanic eruptions are not continuous but intermittent, and as far as the data enable us to judge, have something like an average rate of recurrence, as witness the case of Kilauea; which rate is complicated by rising into epochs of greater activity and falling into epochs of comparative quiescence. So too, according to Mallet, is it with earthquakes and the elevations or depressions caused by them. Sedimentary formations yield indirect evidence. At the mouth of the Mississippi the alternation of strata gives decisive proof of successive sinkings of the surface, that have taken place at tolerably equal intervals. Everywhere in the extensive groups of conformable strata that imply small subsidences recurring with a certain average frequency, we see a rhythm in the action and reaction between the Earth's crust and its contents — a rhythm compounded with those slower ones shown in the termination of groups of strata, and the commencement of other groups not conformable to them.

§85. Perhaps nowhere are illustrations of rhythm so numerous and so manifest as among the phenomena of life. Plants do not, indeed, usually show us any decided periodicities, save those determined by day and night and by the seasons. But in animals we have a great variety of movements in which the alternation of opposite extremes goes on with all degrees of rapidity. The swallowing of food is effected by a wave of constriction passing along the oesophagus; its digestion is largely aided by a muscular action of the stomach that is also undulatory; and the peristaltic motion of the intestines is of like nature. The blood obtained from this food is propelled in pulses, and is aerated by lungs that alternately contract and expand. All locomotion results from oscillating movements. Even where it is apparently continuous, as in many minute forms, the microscope proves the vibration of cilia to be the agency by which the creature is moved smoothly forwards.

Primary rhythms of the organic actions are compounded with secondary ones of longer duration. We see this in the periodic need for food, and in the periodic need for repose. Each meal induces a more rapid rhythmic action of the digestive organs; the pulsation of the heart is accelerated; the inspirations become more frequent. During sleep, on the contrary, these several movements slacken. So that in the course of the twenty-four hours, those small undulations of which the different kinds of organic action are constituted, undergo one long wave of increase and decrease, complicated with several minor waves. Experiments have shown that there are still slower rises and falls of functional activity. Waste and assimilation are not balanced by every meal, but one or other maintains for some time a slight excess; so that a person in ordinary health undergoes an increase and decrease of weight during recurring intervals of tolerable equality. There are oscillations of vigour too. Even men in training cannot be kept stationary at their highest power, but when they have reached it begin to retrograde. Further evidence of rhythm in the vital movements is furnished by invalids. Sundry disorders are named from the intermittent character of their symptoms. Even where the periodicity is not very marked, it is mostly traceable. Patients rarely if ever become uniformly worse; and convalescents have usually their days of partial relapse or of less decided advance.

Aggregates of living creatures illustrate the general truth in other ways. If each species of organism be regarded as a whole, it displays two kinds of rhythm. Life as it exists in every member of such species, is an extremely complex kind of movement, more or less distinct from the kinds of movement which constitute life in other species. This extremely complex kind of movement begins, rises to its climax, declines, and ceases in death. And every individual in each generation thus exhibits a wave of that peculiar activity characterizing the species as a whole. The other form of rhythm is seen in that variation of number which each tribe of animals and plants undergoes. Throughout the unceasing conflict between the tendency of a species to increase and the antagonistic tendencies, there is never an equilibrium: one always predominates. In the case even of a cultivated plant or domesticated animal, where artificial means are used to maintain the supply at a uniform level, oscillations of abundance and scarcity cannot be avoided. And among creatures uncared for by man, such oscillations are usually more marked. After a race of organisms has been greatly thinned by enemies or innutrition, its surviving members become more favourably circumstanced than usual. During the decline in their numbers their food has grown relatively abundant, while their enemies have somewhat diminished from want of prey. The conditions thus remain for some time favourable to their increase, and they multiply rapidly. By-and-by their food is rendered relatively scarce, at the same time that their enemies have become more numerous; and the destroying influences being thus in excess, their number begins to diminish again. Yet one more rhythm, extremely slow, may be traced in the phenomena of Life under their most general aspect. The researches of palaeontologists show that there have been going on, during the vast period of which our sedimentary rocks bear record, successive changes of organic forms. Species have appeared, become abundant, and then disappeared. Genera, at first constituted of but few species, have for a time gone on growing more multiform, and then have declined in the number of their subdivisions: leaving at last but one or two, or none at all. During longer epochs whole orders have thus arisen, culminated, and dwindled away. And even those wider divisions containing many orders have similarly undergone a gradual rise, a high tide, and a long-continued ebb. The stalked Crinoidea, for example, which during the carboniferous epoch became abundant, have almost disappeared: only a single species being extant. Once a large family, the Brachiopoda have now become rare. The shelled Cephalopods, at one time dominant among the inhabitants of the ocean, both in number of forms and of individuals, are in our day nearly extinct. And after an "age of reptiles" has come an age in which reptiles have been in great measure supplanted by mammals. Thus Life on the Earth has not progressed uniformly, but in immense undulations.

§86. It is not manifest that changes of consciousness are in any sense rhythmical. Yet here, too, analysis proves both that the mental state existing at any moment is not uniform, but is decomposable into rapid oscillations, and also that mental states pass through longer intervals of increasing and decreasing intensity.

Though while attending to any single sensation, or any group of related sensations constituting the consciousness of an object, we seem to remain in a persistent and homogeneous condition of mind, self-examination shows that this apparently unbroken mental state is traversed by many minor states, in which various other sensations and preceptions are rapidly presented and disappear. As thinking consists in the establishment of relations, it follows that continuance of it in any one state to the entire exclusion of other states, would be a cessation of thought, that is, of consciousness. So that any seemingly uniform feeling, say of pressure, really consists of portions of that feeling perpetually recurring after momentary intrusions of other feelings and ideas — quick thoughts concerning the place where it is felt, the external object producing it, its consequences, etc. Much more conspicuous rhythms, having longer waves, are seen during the outflow of emotion into dancing, poetry and music. The current of mental energy expended in one of these modes of bodily action, is not continuous but falls into successive pulses. The measure of a dance is produced by the alternation of strong muscular contractions with weaker ones; and, save in measures of the simplest order, such as are found among barbarians and children, this alternation is compounded with longer rises and falls in the degree of muscular excitement. Poetry is a form of speech in which the emphasis is regularly recurrent, that is,in which the muscular effort of pronunciation has definite periods of greater and less intensity: periods that are complicated with others answering to the successive verses. Music more variously exemplifies the law. There are the recurring bars, in each of which there is a primary and a secondary beat. There is the alternate increase and decrease of muscular strain implied by the ascents and descents to the higher and lower notes — ascents and descents composed of smaller waves, breaking the rises and falls of the larger ones, in a mode peculiar to each melody. And then we have, further, the alternations of piano and forte passages. That these several kinds of rhythm, characterizing aesthetic expression, are not, in the common sense of the word, artificial, but are intenser forms of an undulatory movement habitually generated by feeling in its bodily discharge, is shown by the fact that they are all traceable in ordinary speech, which in every sentence has its primary and secondary emphases, and its cadence containing a chief rise and fall complicated with subordinate rises and falls. Still longer undulations may be observed by every one in himself and in others, on occasions of extreme pleasure or extreme pain. During hours in which bodily pain never actually ceases, it has its variations of intensity — fits or paroxysms; and then after these intervals of suffering there usually come intervals of comparative ease. Moral pain has the like smaller and larger waves. One possessed by intense grief does not utter continuous moans, or shed tears with an equable rapidity; but these signs of passion come in recurring bursts. Then after a time during which such stronger and weaker waves of emotion alternate, there comes a calm — a time of comparative deadness; after which dull sorrow rises afresh into acute anguish, with its series of paroxysms. Similarly great delight, as shown by children who display it without control, undergoes variations in intensity: there are fits of laughter and dancing about, separated by pauses in which smiles, and other slight manifestations of pleasure, suffice to discharge the lessened excitement. Nor are there wanting evidences of mental undulations greater in length than any of these. We continually hear of moods which recur at intervals. Many persons have their days of vivacity and days of depression. Others have periods of industry following periods of idleness; and times at which particular subjects or tastes are cultivated with zeal, alterating with times at which they are neglected. Respecting which slow oscillations the only qualification to be made is, that being affected by numerous influences they are irregular.

§87. In nomadic societies the changes of place, determined by exhaustion or failure of the supply of food, are periodic; and in many cases recur with the seasons. Each tribe that has become partially fixed in its locality, goes on increasing until, under pressure of hunger, there results migration of some part of it — a process repeated at intervals. From such excesses of population, and such waves of migration, come conflicts with other tribes; which are also increasing and tending to diffuse themselves. Their antagonisms result not in a uniform motion, but in an intermittent one. War, exhaustion, recoil-peace, prosperity, and renewed aggression: — see here the alteration as occurring among both savage and civilized peoples. And irregular as is this rhythm, it is not more so than the different sizes of the societies, and the involved causes of variation in their strengths, would lead us to anticipate.

Passing from external to internal social changes, we meet this backward and forward movement under many forms. In commercial currents it is especially conspicuous. Exchange during early times is carried on mainly at fairs, held at long intervals. The flux and reflux of people and commodities which each of these exhibits, becomes more frequent as national development brings greater social activity. The rapid rhythm of weekly markets begins to supersede the slow rhythm of fairs. And eventually exchange becomes at some places so active, as to bring about daily meetings of buyers and sellers — a daily wave of accumulation and distribution of cotton, or corn, or capital. In production and consumption there are undulations almost equally obvious. Supply and demand are never completely adjusted, but each, from time to time in excess, leads presently to excess of the other. Farmers who have one season grown wheat abundantly, are disgusted with the consequent low price, and next season, sowing a much smaller quantity, bring to market a deficient crop; whence follows a converse effect. Consumption undergoes parallel undulations that need not be specified. The balancing of supplies between different districts, too, entails oscillations. A place at which some necessary of life is scarce, becomes a place to which currents of it are set up from other places where it is relatively abundant; and these currents lead to a wave of accumulation where they meet — a glut: whence follows a recoil — a partial return of the currents. But the undulatory character of these actions is best seen in the rises and falls of prices. These, when tabulated and reduced to diagrams, show us in the clearest manner how commercial movements are compounded of oscillations of various magnitudes. The price of consols or the price of wheat, as thus represented, is seen to undergo vast ascents and descents having highest and lowest points that are reached only in the course of years. These largest waves of variation are broken by lesser ones extending over periods of months. On these come others severally having a week or two's duration. And were the changes marked in greater detail, we should see the smaller undulations that take place each day and the still smaller ones which brokers telegraph from hour to hour. The whole outline would show a complication like that of a vast ocean-swell, having on its surface large billows, which themselves bear waves of moderate size, covered by wavelets, that are roughened by a minute ripple. Similar diagrammatic representations of births, marriages, and deaths, of disease, of crime, of pauperism, exhibit involved conflicts of rhythmical motions throughout society under these several aspects.

There are like traits in social changes of more complex kinds. Both in England and on the Continent the actions and reactions of political progress are now generally recognized. Religion has its periods of exaltation and depression — generations of belief and self-mortification, following generations of indifference and laxity. There are poetical epochs, and epochs in which the sense of the beautiful seems almost dormant. Philosophy, after having been awhile dominant, lapses for a long season into neglect, and then again slowly revives. Each concrete science has its eras of deductive reasoning, and its eras in which attention is chiefly directed to collecting and colligating facts. And that in such minor phenomena as those of fashion, there are oscillations from one extreme to the other, is a trite observation.

As may be foreseen, social rhythms well illustrate the irregularity that results from combination of many causes. Where the variations are those of one simple element in national life, as the supply of a particular commodity, we do indeed witness a return, after many involved movements, to a previous state — the price becomes what it was before: implying a like relative abundance. But where the action is one into which many factors enter, there is never a complete recurrence. A political reaction never brings round just the old form of things. The rationalism of the present day differs widely from the rationalism of the last century. And though fashion from time to time revives extinct types of dress, these always reappear with decided modifications.

§88. Rhythm being thus manifested in all forms of movement, we have reason to suspect that it is determined by some primordial condition to action in general. The tacit implication is that it is deducible from the persistence of force. This we shall find to be the fact.

When the prong of a tuning-fork is pulled on one side by the finger, some extra tension is produced among its cohering particles, which resist any force that draws them out of their state of equilibrium. As much force as the finger exerts, so much opposing force arises among the cohering particles. Hence, when the prong is liberated, it is urged back by a force equal to that used in detecting it. When, therefore, the prong reaches its original position, the force impressed during its recoil, has generated in it a corresponding amount of momentum — an amount nearly equivalent to the force originally impressed (nearly, we must say, because a certain portion has gone in giving motion to the air, and a certain other portion has been transformed into heat). This momentum carries the prong beyond the position of rest, nearly as far as it was originally drawn in the reverse direction; until at length, being gradually used up in producing an opposing tension among the particles, it is all lost. This opposing tension then generates a second recoil, and so on continually: the vibration eventually ceasing only because at each movement a certain amount of force goes in creating atmospheric and ethereal undulations. Now evidently this repeated action and reaction is a consequence of the persistence of force. The force exerted by the finger in bending the prong cannot disappear. Under what form then does it exist? It exists under the form of that cohesive tension which it has generated among the particles. This cohesive tension cannot cease without an equivalent result. What is its equivalent result? The momentum generated in the prong while being carried back to its position of rest. This momentum too — what becomes of it? It must either continue as momentum, or produce some correlative force of equal amount. It cannot continue as momentum, since change of place is resisted by the cohesion of the parts; and thus it gradually disappears by being transformed into tension among these parts. This is retransformed into the equivalent momentum; and so on continuously. If, instead of motion that is directly antagonized by the cohesion of matter, we consider motion through space, as of a comet, the same truth presents itself under another form. Though while it is approaching the Sun no opposing force seems at work, and therefore no cause of rhythm, yet its own accumulated momentum must eventually carry the moving body beyond the attracting body; and so must become a force in conflict with that which generated it. This force cannot be destroyed, but it can have its direction changed by the still continued attraction: the result being that a passage round the attracting body is followed by a retreat during which this embodied force, gradually becoming non-apparent, is transformed into gravitative strain, until all of it having been thus transformed there begins a return from aphelion.

Before ending, two qualifications must be made. As the rhythm of motion itself postulates continuity of motion, it cannot be looked for when motion has suddenly become invisible. A hint tacitly given in §82 implies that what we may call a fragmentary motion — a motion which under its perceptible form is suddenly brought to an end — cannot under that form exhibit rhythm: instance the stoppage of a hammer by an anvil. In such cases, however, we observe that this non-continuous motion is transformed into motions that are continuous and rhythmical — the sound-waves, the ether-waves of the heat generated, and the waves of vibration sent through the mass struck: the rhythms of these motions continuing as long as the motions themselves do.

The other qualification is that the motions shall be those occurring within a closed system, such as is constituted by our own Sun, planets, satellites, and periodic comets. If a body approaching a centre of attraction from remote space, has any considerable proper motion not towards that centre, this body, passing round it, may take a course which negatives return — an hyperbola. I say an hyperbola because the chances against a parabolic course are infinity to one.

But bearing in mind these two qualifications, of which the last may be considered almost nominal, we may conclude that under the conditions existing within our Solar System and among terrestrial phenomena, rhythm, everywhere arising from the play of antagonist forces, is a corollary from the persistence of force.

Chapter 11

Recapitulation, Criticism, and Recommencement

§89. Let us pause awhile to consider how far the contents of the foregoing chapters go towards forming a body of knowledge answering to the definition of Philosophy.

In respect of its generality, the proposition enunciated and exemplified in each chapter is of the required kind — is a proposition transcending those class-limits which Science, as currently understood, recognizes. "The Indestructibility of Matter" is a truth not belonging to mechanics more than to chemistry — a truth assumed alike by molecular physics and the physics that deals with sensible masses — a truth which the astronomer and the biologist equally take for granted. Not merely do those divisions of Science which deal with the movements of celestial and terrestrial bodies postulate "The Continuity of Motion," but it is no less postulated in the physicist's investigations into the phenomena of light and heat, and is tacitly if not avowedly, implied in the generalizations of the higher sciences. So, too, "The Persistence of Force," involved in each of the preceding propositions, is co-extensive with them, as is also its corollary, "The Persistence of Relations among Forces." These are not highly general truths; they are universal truths. Passing to the deductions drawn from them, we see the same thing. That force is transformable, and that between its correlates there exist quantitative equivalences, are ultimate facts not to be classed with those of mechanics, or thermology, or electricity, or magnetism; but they are frustrated throughout phenomena of every order. Similarly, the law that motion follows the line of least resistance or the line of greatest traction or the resultant of the two, we found to be an all-pervading law; conformed to alike by each planet in its orbit, and by, the moving matters, aerial, liquid, and solid, on its surface-conformed to no less by every organic movement and process than by every inorganic movement and process. And so, likewise, it has been shown that rhythm is exhibited universally, from the slow gyrations of double stars down to the inconceivably rapid oscillations of molecules — from such terrestrial changes as those of recurrent glacial epochs down to those of the winds and tides and waves; and is no less conspicuous in the functions of living organisms, from pulsations of the heart up to paroxysms of the emotions.

These truths have the character which constitutes them parts of Philosophy. They are truths which unify concrete phenomena belonging to all divisions of Nature; and so must be components of that all-embracing conception of things which Philosophy seeks.

§90. But now what parts do these truths play in forming such a conception? Does any one of them singly convey an idea of the Cosmos: meaning by that word the totality of the manifestations of the Unknowable? Do all of them taken in succession yield us an adequate idea of this kind? Do they even when thought of in combination compose anything like such an idea? To each of these questions the answer must be — No.

Neither these truths nor any other such truths, separately or jointly, constitute that integrated knowledge in which Philosophy finds its goal. It has been supposed by one thinker that when Science has reduced all more complex laws to some most simple law, as of molecular action, knowledge will have reached its limit. Another authority holds that all minor facts are so merged in the major fact that the force everywhere in action is nowhere lost, that to express this is to express "the constitution of the universe." But either conclusion implies a misapprehension of the problem.

For these are all analytical truths, and no analytical truth, nor any number of analytical truths, will make up that synthesis of thought which alone can be an interpretation of the synthesis of things. The decomposition of phenomena into their elements is but a separation for understanding phenomena in their state of composition, as actually manifested. To have ascertained the laws of the factors is not to have ascertained the laws of their co-operation. The thing to be expressed is the joint product of the factors under all its various aspects. A clear comprehension of this matter is important enough to justify some further exposition.

§91. Suppose a chemist, a geologist, and a biologist, have given the deepest explanations furnished by their respective sciences, of the processes going on in a burning candle, in a region changed by earthquake, and in a growing plant. To the assertion that their explanations are not the deepest possible, they will probably rejoin, "What would you have? What remains to be said of combustion when light and heat and the dissipation of substance have all been traced down to the liberation of molecular motion as their common cause? When all the actions accompanying an earthquake are explained as consequent upon the slow loss of the Earth's internal heat, how is it possible to go lower? When the influence of light on the oscillations of molecules has been proved to account for vegetal growth, what is the imaginable further rationale? You ask for a synthesis. You say that knowledge does not end with the resolution of phenomena into the actions of certain factors, each conforming to ascertained laws; but that the laws of the factors having been ascertained, there comes the chief problem — to show how from their joint action result the phenomena in all their complexity. Well, do not the above interpretations satisfy this requirement? Do we not, starting with the molecular motions of the elements concerned in combustion, build up synthetically an explanation of the light, and the heat, and the produced gases, and the movements of the produced gases? Do we not, setting out from the still-continued radiation of the Earth's heat, construct by synthesis a clear conception of its nucleus as contracting, its crust as collapsing, as becoming shaken and fissured and contorted and burst through by lava? And is it not the same with the chemical changes and accumulation of matter in the growing plant?"

To all which the reply is, that the ultimate interpretation to be reached by Philosophy, is a universal synthesis comprehending and consolidating such special syntheses. The synthetic explanations which Science gives, even up to the most general, are more or less independent of one another. Must there not be a deeper explanation including them? Is it to be supposed that in the burning candle, in the quaking Earth, and in the organism that is increasing, the processes as wholes are unrelated to one another? If it be admitted that each of the factors concerned always operates in conformity to a law, is it to be concluded that their co-operation conforms to no law? These various changes, artificial and natural, organic and inorganic, which for convenience sake we distinguish, are not from the highest point of view to be distinguished; for they are all changes going on in the same Cosmos, and forming parts of one vast transformation. The play of forces is essentially the same in principle throughout the whole region explored by our intelligence; and though, varying infinitely in their proportions and combinations, they work out results everywhere different, yet there cannot but be among these results a fundamental community. The question to be answered is — what is the common element in the histories of all concrete processes?

§92. To resume, then, we have now to seek a law of composition of phenomena, co-extensive with those laws of their components set forth in the foregoing chapters. Having seen that matter is indestructible, motion continuous, and force persistent — having seen that forces perpetually undergo transformations, and that motion, following the line of least resistance, is always rhythmic, it remains to find the formula expressing the combined consequences of the laws thus separately formulated.

Such a formula must be one that specifies the course of the changes undergone by both the matter and the motion. Every transformation implies re-arrangement of parts; and a definition of it, while saying what has happened to the sensible or insensible portions of substance concerned, must also say what has happened to the movements, sensible or insensible, which the rearrangement of parts implies. Further, unless the transformation always goes on in the same way and at the same rate, the formula must specify the conditions under which it commences, ceases, and is reversed.

The law we seek, therefore, must be the law of the continuous redistribution of matter and motion. Absolute rest and permanence do not exist. Every object, no less than the aggregate of all objects, undergoes from instant to instant some alteration of state. Gradually or quickly it is receiving motion or losing motion, while some or all of its parts are simultaneously changing their relations to one another. And the question is — What dynamic principle, true of the metamorphosis as a whole and in its details, expresses these ever-changing relations?

Chapter 12

Evolution and Dissolution

§93. An entire history of anything must include its appearance out of the imperceptible and its disappearance into the imperceptible. Any account of an object which begins with it in a concrete form, or leaves off with it in a concrete form, is incomplete; since there remains an era of its existence undescribed and unexplained. While admitting that knowledge is limited to the phenomenal, we have, by implication, asserted that the sphere of knowledge is co-extensive with the phenomenal — co-extensive with all modes of the Unknowable which can affect consciousness. Hence, wherever we now find Being so conditioned as to act on our senses, there arise the questions — how came it to be thus conditioned? and how will it cease to be thus conditioned? Unless on the assumption that it acquired a sensible form at the moment of perception, and lost its sensible form the moment after perception, it must have had an antecedent existence under this sensible form, and will have a subsequent existence under this sensible form. And knowledge of it remains incomplete until it has united the past, present, and future histories into a whole.

Our daily sayings and doings presuppose more or less such knowledge, actual or potential, of states which have gone before and of states which will come after. Knowing any man personally, implies having before seen him under a shape much the same as his present shape; and knowing him simply as a man, implies the inferred antecedent states of infancy, childhood, and youth. Though the man's future is not known specifically, it is known generally. that he will die and decay, are facts which complete in outline the changes to be gone through by him. So with all objects around. The pre-existence under concrete forms of our woollens, silks, and cottons, we can trace some distance back. We are certain that our furniture consists of matter which was aggregated by trees within these few generations. Even of the stones composing the walls of the house, we are able to say that years or centuries ago, they formed parts of some stratum in the Earth. Moreover, respecting the hereafter of the wearable fabrics, the furniture, and the walls, we can assert this much, that they are all decaying, and in periods of various lengths will lose their present coherent shapes. This information which all men gain conceding the past and future careers of surrounding things, Science continues unceasingly to extend. To the biography of the individual man, it adds an intra-uterine biography beginning with him as a minute germ; and following out his ultimate changes it finds his body resolved into certain gaseous products of decomposition. Not stopping short at the sheep's back and the caterpillar's cocoon, it identifies in wool and silk the nitrogenous matters absorbed by the sheep and the caterpillar from plants. The substance of a plant's leaves, in common with the wood from which furniture is made, it again traces back to certain gases in the air and certain minerals in the soil. And the stratum of stone which was quarried to build the house, it leads was once a loose sediment deposited in an estuary or on the sea-bottom.

If, then, the past and the future of each object is a sphere of possible knowledge; and if intellectual progress consists largely, if not mainly, in widening our acquaintance with this past and this future; it is obvious that the limit towards which we progress is an expression of the whole past and the whole future of each object and the aggregate of objects. It is no less obvious that this limit, if reached, can be reached only in a very qualified sense: inference more than observation must bring us to it. This garden-annual we trace down to a seed planted in the spring, and analogy helps us back to the microscopic ovule whence the seed arose. Observation, verifying forecast, extends our knowledge to the flowers and the seeds, and afterwards to the death and decay which, sooner or later, ends in diffusion, partly through the air, partly through the soil. Here the rise of the aggregate out of the imperceptible and its passage back into the imperceptible is indistinct at each extreme. Nevertheless we may say that in the case of this organism, as of organisms in general, the account, partially based on observation but largely based on inference, fulfils the definition of a complete history fairly well. But it is otherwise throughout the inorganic world. Inference here plays the chief part. Only by the piecing together of scattered facts can we form any conception of the past or future of even small inorganic masses, and still less can we form it of greater ones; and when we come to the vast masses forming our Solar System, the limits to their existence, alike in the past and in the future, can be known but inferentially: direct observation no longer aids us. Still, science leans more and more to the conclusion that these also once emerged from the imperceptible through successive stages of condensation and will in an immeasurably remote future lapse again into the imperceptible. So that here, too, the conception of a complete history is in a sense applicable, though we can never fill it out in more than an indefinite way.

But after recognizing the truth that our knowledge is limited to the phenomenal and the further truth that even the sphere of the phenomenal cannot be penetrated to its confines, we must nevertheless conclude that so far as is possible philosophy has to formulate this passage from the imperceptible into the perceptible, and again from the perceptible into the imperceptible.

This last sentence contains a tacit suggestion which must, however, be excluded. The apparent implication is that a confessedly imperfect theory may, by extension after the manner described, be changed into an avowedly perfect one. But we may anticipate that the extension will prove in large measure impracticable. Complete accounts of the beginnings and ends of individual objects cannot in most cases be reached: their initial and terminal stages are left vague after investigation has done its best. Still more, then, with the totality of things must we conclude that the initial and terminal stages are beyond the reach of our intelligence. As we cannot fathom either the infinite past or the infinite future, it follows that both the emergence and immergence of the totality of sensible existences must ever remain matters of speculation only: speculation more or less justified by reasoning from established data, but still — speculation.

Hence the conception of Philosophy above implied must be regarded as an ideal to which the real can never do more than approximate. Ideals in general — even those of the exact sciences — cannot be reached, but can only be nearly approached; and yet they in common with other ideals, are indispensable aids to inquiry and discovery. So that while it may remain the aim of philosophy to give that comprehensive account of things which includes passage from the imperceptible into the perceptible and again from the perceptible into the imperceptible, yet it may be admitted that it must ever fall short of this aim. Still, while recognizing its inevitable incompleteness, we infer that such approach to completeness as is possible will be affected under guidance of the conceptions reached in the last two chapters. That general law of the redistribution of matter and motion which we lately saw is required to unify the various kinds of changes, must also be one that unifies the successive changes which sensible existences, separately and together, pass through between their appearance and their disappearance. Only by some formula combining these characters can knowledge be reduced to a coherent whole.

§94. Already in the foregoing paragraphs the formula is foreshadowed. Already in recognizing the fact that Science, tracing back the histories of various objects, finds their components were once in diffused states, and forecasting their futures sees that diffused states will be again assumed by them, we have recognized the facts that the formula must be one comprehending the two opposite processes of concentration and dispersion. And already in thus describing the general nature of the formula, we have approached a specific expression of it. The change from a dispersed, imperceptible state to a concentrated, perceptible state, is an integration of matter and concomitant dissipation of motion; and the change from a concentrated, perceptible state to a dispersed, imperceptible state, is an absorption of motion and concomitant disintegration of matter. These are truisms. Constituent parts cannot aggregate without losing some of their relative motion; and they cannot separate without more relative motion being given to them. We are not concerned here with any motion which the components of a mass have with respect to other masses: we are concerned only with the motion they have with respect to one another. Confining our attention to this internal motion, and to the matter possessing it, the axiom which we have to recognize is that a progressing consolidation involves a decrease of internal motion; and that increase of internal motion involves a progressing unconsolidation.

When taken together, the two opposite processes thus formulated constitute the history of every sensible existence under its simplest form. Loss of internal motion and consequent integration, eventually followed by gain of internal motion and consequent disintegration — see here a statement comprehensive of the entire series of changes passed through: comprehensive in an extremely general way, as any statement which holds of sensible existences at large must be; but still, comprehensive in the sense that all the changes gone through fall within it. This will probably be thought too sweeping an assertion, but we shall quickly find it justified.

§95. For here we have to note the further all-important fact, that every change suffered by every sensible existence, is a change in one or other of these two opposite directions. Apparently an aggregate which has passed out of some originally discrete state into a concrete state, thereafter remains for an indefinite period without undergoing further integration, and without beginning to disintegrate. But this is untrue. All things are growing or decaying, accumulating matter or wearing away, integrating or disintegrating. All things are varying in their temperatures, contracting or expanding, integrating or disintegrating. Both the quantity of matter contained in an aggregate and the quantity of motion contained in it, increase or decrease; and increase or decrease of either is an advance towards greater diffusion or greater concentration. Continued losses or gains of substance, however slow, imply ultimate disappearance or indefinite enlargement; and losses or gains of insensible motion will, if continued, produce complete integration or complete disintegration. Heat rays falling on a cold mass, augmenting the molecular motions throughout it, and causing it to occupy more space, are beginning a process which if carried far will disintegrate the mass into liquid, and if carried farther will disintegrate the liquid into gas. Conversely, the decrease of bulk which a volume of gas undergoes as it parts with some of its molecular motion, is a decrease which, if the loss of molecular motion proceeds, will be followed by liquefaction and eventually by solidification. And since there is no such thing as a constant temperature, the necessary inference is that every aggregate is at every moment progressing towards either greater concentration or greater diffusion.

§96. A general idea of these universal actions under their simplest aspects having been obtained, we may now consider them under certain more complex aspects. Thus far we have supposed one or other of the two opposite processes to go on alone — we have supposed an aggregate to be either losing motion and integrating or gaining motion and disintegrating. But though every change furthers one or other of these processes, neither process is ever unqualified by the other. For each aggregate is at all times both gaining motion and losing motion.

Every mass from a grain of sand to a planet, radiates heat to other masses, and absorbs heat radiated by other masses; and in so far as it does the one it becomes integrated, while in so far as it does the other it becomes disintegrated. In inorganic objects this double process ordinarily works but unobtrusive effects. Only in a few cases, among which that of a cloud is the most familiar, does the conflict produce rapid and marked transformations. One of these floating bodies of vapour expands and dissipates, if the amount of molecular motion it receives from the Sun and Earth exceeds that which it loses by radiation into space and towards adjacent surfaces; while, contrariwise, if, drifting over cold mountain-tops, it radiates to them much more heat than it receives, the loss of molecular motion is followed by increasing integration of the vapour, ending in the aggregation of it into liquid and the fall of rain. Here, as elsewhere, the integration or the disintegration is a differential result.

In living aggregates, and especially in animals, these conflicting processes go on with great activity under several forms. There is not merely what we may call the passive integration of matter, which inanimate masses effect by simple molecular attractions, but there is an active integration of it under the form of food. In addition to that passive superficial disintegration which inanimate objects suffer from external agents, animals produce in themselves active internal disintegration, by absorbing such agents. While, like inorganic aggregates, they passively radiate and receive motion, they are also active absorbers of motion latent in food, and active expenders of that motion. But notwithstanding this complication of the two processes, and the immense exaltation of the conflict between them, it remains true that there is always a differential progress towards either integration or disintegration. During the earlier part of the cycle of changes the integration predominates — there goes on what we call growth. The middle part of the cycle is usually characterized, not by equilibrium between the integrating and disintegrating processes, but by alternate excesses of them. And the cycle closes with a period in which the disintegration, beginning to predominate, eventually puts a stop to integration, and after death undoes what integration had originally done. At no moment are assimilation and waste so balanced that no increase or decrease of mass is going on. Even in cases where one part is growing while other parts are dwindling, and even in cases where different parts are differently exposed to external sources of motion, so that some are expanding while others are contracting, the truth still holds. For the chances are infinity to one against these opposite changes balancing one another; and if they do not balance, the aggregate as a whole is integrating or disintegrating.

Hence that the changes ever going on are from a diffused imperceptible state to a concentrated perceptible state, and back again to a diffused inmperceptible state, must be that universal law of redistribution of matter and motion, which serves to unify the seemingly diverse groups of changes, as well as the entire course of each group.

§97. The processes thus everywhere in antagonism, and everywhere gaining now a temporary and now an enduring predominance the one over the other, we call Evolution and Dissolution. Evolution under its most general aspect is the integration of matter and concomitant dissipation of motion; while Dissolution is the absorption of motion and concomitant disintegration of matter.

The last of these titles answers its purpose tolerably well, but the first is open to grave objections. Evolution has other meanings, some of which are incongruous with, and some even directly opposed to, the meaning here given to it. The evolution of a gas is literally an absorption of motion and distintegration of matter, which is exactly the reverse of that which we here call Evolution. As ordinarily understood, to evolve is to unfold, to open and expand, to throw out; whereas as understood here, the process of evolving, though it implies increase of a concrete aggregate, and in so far an expansion of it, implies that its component matter has passed from a more diffused to a more concentrated state — has contracted. The antithetical word Involution would more truly express the nature of the change; and would, indeed, describe better those secondary characters of it which we shall have to deal with presently. We are obliged, however, notwithstanding the liabilities to confusion resulting from these unlike and even contradictory meanings, to use Evolution as antithetical to Dissolution. The word is now so widely recognized as signifying, not, indeed, the general process above described, but sundry of its most conspicuous varieties, and certain of its secondary but most remarkable accompaniments, that we cannot now substitute another word.

While, then, we shall by Dissolution everywhere mean the process tacitly implied by its ordinary meaning — the absorption of motion and disintegration of matter; we shall everywhere mean by Evolution, the process which is always an integration of matter and dissipation of motion, but which, as we shall now see, is in most cases much more than this.

Chapter 13

Simple and Compound Evolution

§98. Where the only forces at work are those directly tending to produce aggregation or diffusion, the whole history of an aggregate will comprise no more than the approaches of its components towards their common centre and their recessions from their common centre. The process of evolution, including nothing beyond what was described at the outset of the last chapter, will be simple.

Again, where the forces which cause movements towards a common centre greatly exceed all other forces, any changes additional to those of aggregation will be comparatively insignificant: there will be integration slightly modified by further kinds of redistribution.

Or if because of the smallness of the mass, or because of the little motion it receives from without in return for the motion it loses, the integration proceeds rapidly; there will similarly be wrought but insignificant effects by secondary forces, even though these are considerable.

But when, conversely, the integration is slow. either, because the quantity of motion contained in the aggregate is relatively great; or because, though the quantity of motion which each part possesses is not relatively great, the large size of the aggregate prevents easy dissipation of the motion. or because, though motion is rapidly lost more motion is rapidly received; then, other forces will cause in the aggregate sensible modifications. Along with the change constituting integration, there will take place further changes. The Evolution, instead of being simple, will be compound.

These several propositions require some explanation.

§99. So long as a body moves freely through space, every force which acts on it produces an equivalent in the shape of some change in its motion. No matter how high its velocity the slightest lateral traction or resistance causes it to deviate from its line of movement; and the effect of the perturbing influence goes on accumulating in the ratio of the squares of the times during which its action continues uniform. But when this same body is held fast by gravitation or cohesion, small incident forces, instead of giving it some relative motion through space, are otherwise dissipated.

What thus holds of masses holds, in a qualified way, of the sensible parts of masses, and of molecules. As the sensible parts of a mass, and the molecules of a mass, are, by virtue of their aggregation, not perfectly free, it is not true of each of them, as of a body moving through space, that every incident force produces an equivalent change of position: part of the force goes in working other changes. But in proportion as the parts of the molecules are freely bound together, incident forces effect marked re-arrangements among them. Where the integration is so slight that the parts, sensible or insensible, are almost independent, they are almost completely amenable to every additional action; and along with the concentration going on there go on other re-distributions. Contrariwise, where the parts are so close that what we call the attraction of cohesion is great, additional actions, unless intense, have little power to cause secondary re-arrangements. The firmly-united parts do not change their relative positions in obedience to small perturbing forces; but each small perturbing force usually does nothing more than temporarily modify the insensible molecular motions.

How may we best express this difference in general terms? An aggregate that is widely diffused, or but little integrated, is an aggregate containing a large quantity of motion — actual or potential or both. An aggregate that has become completely integrated or dense, is one containing comparatively little motion: most of the motion its parts once had has been lost during the integration that has rendered it dense. Hence, other things equal, in proportion to the quantity of motion an aggregate contains will be the quantity of secondary change in the arrangement of its parts that accompanies the primary change in their arrangements. Hence also other things equal, in proportion to the time during which the internal motion is retained, will be the quantity of this secondary re-distribution. It matters not how these conditions are fulfilled. Whether the internal motion continues great because the components are of a kind that will not readily aggregate, or because surrounding conditions prevent them from parting with their motion, or because the loss of their motion is impeded by the size of the aggregate they form, or because they directly or indirectly obtain more motion in place of that which they lose; it throughout remains true that much retained internal motion renders secondary re-distributions facile, and that long retention of it makes possible an accumulation of such secondary re-distributions. Conversely, non-fulfilment of these conditions, however caused, entails opposite results. Be it that the components of the aggregate have special aptitudes to integrate quickly, or be it that the smallness of the aggregate permits easy escape of their motion, or be it that they receive little or no motion in exchange for that which they lose; it alike holds that but little secondary re-distribution can accompany the primary re-distribution constituting their integration.

Let us, before studying simple and compound Evolution as thus determined, contemplate a few cases in which the quantity of internal motion is artificially changed, and note the effects on the re-arrangement of parts.

§100. When a vessel has been filled to the brim with loose fragments, shaking it causes them to settle down into less space, so that more may be put in. And when among th e fragments there are some of much greater specific gravity than the rest, these, in the course of a prolonged shaking, find their way to the bottom. What are these results, expressed in general terms? We have a group of units acted on by an incident force — the attraction of the Earth. So long as these units are not agitated, this incident force cannot change their relative positions; agitate them, and their loose arrangement passes into a more compact arrangement. Again, so long as they are not agitated, the incident force cannot separate the heavier units from the lighter; agitate them, and the heavier units begin to segregate. Mechanical disturbances of more minute kinds, acting on the parts of much denser masses, produce analogous effects. A piece of iron which, when it leaves the workshop, is fibrous in structure, becomes crystalline if exposed to a perpetual jar. The polar forces mutually exercised by the atoms, fail to change their disorderly arrangement into an orderly arrangement while they are relatively quiescent; but these forces succeed in rearranging them when they are kept in a state of intestine motion. Similarly, the fact that a bar of steel suspended in the magnetic meridian and repeatedly struck, becomes magnetized, is ascribed to a re-arrangement of particles produced by the magnetic force of the Earth when vibrations are propagated through them. Now imperfectly as these cases parallel those we are considering. they yet serve roughly to illustrate the effect which adding to the quantity of motion an aggregate contains, has in facilitating re-distribution of its components.

More fully illustrative are the instances in which, by artificially adding to or substracting from the molecular motion called its heat, we give an aggregate increased or diminished facility of re-arranging its molecules. The process of tempering steel or annealing glass, shows us that internal re-distribution is aided by insensible vibrations, as we have just seen it to be by sensible vibrations. When some molten glass is dropped into water, and its outside is thus, by sudden solidification, prevented from participating in that contraction which subsequent cooling of the inside tends to produce; the units are left in such a state of tension, that the mass flies into fragments if a small portion be broken off. But if this mass be kept for a day or two at a considerable heat, though a heat not sufficient to alter its form, this extreme brittleness disappears: the component particles being thrown into greater agitation, the tensile forces are enabled to re-arrange them into a state of equilibrium. Much more conspicuous is the effect of heat where the re-arrangement of parts taking place is that of visible segregation. An instance is furnished by the subsidence of fine precipitates. These sink down very slowly from solutions which are cold; while warm solutions deposit them with comparative rapidity. That is to say, exalting the molecular oscillation throughout the mass, allows the suspended particles to separate more readily from the particles of fluid. The influence of heat on chemical changes is so familiar that examples are scarcely needed. Be the substances concerned gaseous, liquid, or solid, it equally holds that their chemical unions and disunions are aided by rise of temperature. Affinities which do not suffice to effect the re-arrangement of mixed units that are in a state of feeble agitation, suffice to effect it when the agitation is raised to a certain point. And so long as this molecular motion is not great enough to prevent those chemical cohesions which the affinities tend to produce, exalting it facilitates chemical re-arrangement.

Let us pass to illustrations of a different class. Other things equal, the liquid form of matter implies a greater quantity of contained motion than the solid form: the liquidity being itself a consequence of such greater quantity. Hence, an aggregate made up partly of liquid matter and partly of solid matter, contains more motion than one which, otherwise like it, is made up wholly of solid matter. It is inferable, then, that a liquid-solid aggregate, or, as we call it, a plastic aggregate, will admit of internal re-distribution with comparative facility; and the inference is verified by experience. While a magma of unlike substances ground up with water continues thin there goes on a settlement of its heavier components — a separation of them from the lighter. As the water evaporates this separation is impeded, and ceases when the magma becomes thick. But even when it has reached the semi-solid state in which gravitation fails to cause further segregation of its mixed components, other forces may still produce segregation: witness the fact that when the pasty mixture of ground flints and kaolin, prepared for making porcelain, is kept some time, it becomes gritty and unfit for use — the particles of silica separate themselves from the rest and unite into grains; or witness the fact known to every housewife, that in long-kept currant-jelly the sugar takes the shape of imbedded crystals.

No matter then under what form the motion contained by an aggregate exists — be it visible agitation, or such vibrations as produce sound, be it molecular motion absorbed from without, or the constitutional molecular motion of some component liquid, the same truth holds. Incident forces work secondary re-distributions easily when the contained motion is large in quantity; and work them with increasing difficulty as the contained motion diminishes.

§101. Yet another class of facts which fall within the same generalization must be named before proceeding. They are those presented by certain contrasts in chemical stability. Speaking generally, stable compounds contain but little molecular motion, and in proportion as the contained molecular motion is great the instability is great.

The most common and marked illustration of this, is that chemical stability decreases as temperature increases. Compounds of which the elements are strongly united and compounds of which the elements are feebly united, are alike in this, that heating them or adding to the quantities of their contained molecular motion, diminishes the strengths of the unions of their elements; and by continually augmenting the contained molecular motion, a point is in each case reached at which the union is destroyed. That is to say the re-distribution of matter which constitutes simple chemical decomposition, is easy in proportion as the quantity of contained motion is great. The like holds with double decompositions. Two compounds, A B and C D, mingled together and kept at a low temperature, may severally remain unchanged: the cross-affinities between their components may fail to cause re-distribution. Raise the heat of the mixture, and re-distribution takes place; ending in the formation of the compounds A C and B D.

Another truth having a like implication, is that chemical elements which, as they ordinarily exist, contain much motion, have combinations less stable than those of which the elements, as they ordinarily exist, contain little motion. The gaseous form of matter implies a relatively large amount of molecular motion, while the solid form implies a relatively small amount. What are the traits of their respective compounds? Those which the permanent gases form with one another, cannot resist high temperatures: most of them are easily decomposed by heat; and at a red heat, even the stronger ones yield up their components. On the other hand, the chemical unions between elements that are solid except at high temperatures, are very stable. In many, if not indeed in most, cases, such unions are not destroyed by any heat we can produce.

There is, again, the relation, which appears to have a kindred meaning, between instability and amount of composition. "In general, the molecular heat of a compound increases with the degree of complexity." With increase of complexity there also goes increased facility of decomposition. Whence it follows that molecules with contain much motion in virtue of their complexity, are those of which the components are most easily re-distributed. This holds not only of the complexity arising from the union of several unlike elements; it holds also of the complexity arising from the union of the same elements in higher multiples. Matter has two solid states, distinguished as crystalloid and colloid; of which the first is due to union of the individual atoms or molecules, and the second to the union of groups of such individual atoms or molecules; and of which the first is stable and the second unstable.

But the most conclusive illustration is furnished by the combinations into which nitrogen enters. These are specially unstable and contain specially great quantities of motion. A peculiarity of nitrogen is that, instead of giving out heat when it combines with other elements, it absorbs heat. Besides carrying with it into the liquid or solid compound it forms, the motion which previously constituted it a gas, it takes up additional motion; and where the other element with which it unites is gaseous, the molecular motion proper to this, also, is locked up in the compound. Now these nitrogen-compounds are unusually prone to decomposition; and the decompositions of many of them take place with extreme violence. All our explosive substances are nitrogenous — the most destructive of them all, chloride of nitrogen, being one which contains the immense quantity of motion proper to its component gases, plus a further quantity of motion.

Evidently these general chemical truths are parts of the more general physical truth we are tracing out. We see in them that what holds of sensible masses, holds also of the insensible masses we call molecules. Like the aggregates formed of them, these ultimate aggregates become more or less integrated according as they lose or gain motion; and like them also, according as they contain much or little motion, they are more or less liable to undergo secondary re-distributions along with the primary re-distribution.

§102. And now having brought this general principle clearly into view, let us observe how, in conformity with it, Evolution becomes, according to the conditions, either simple or compound.

If a little sal-ammoniac or other volatile solid be heated, it is disintegrated by the absorbed molecular motion and rises in gas. If this gas comes in contact with a cold surface, and loses it excess of molecular motion, integration takes place — the substance assumes the form of crystals. This is a case of simple evolution. The concentration of matter and dissipation of motion do not here proceed gradually — do not pass through stages; but the molecular motion which caused assumption of the gaseous state being dissipated, the matter passes suddenly to a solid state. The result is that along with this primary re-distribution there go on no appreciable secondary re-distributions. Substantially the same thing holds with crystals deposited from solutions. Loss of that molecular motion which, down to a certain point, keeps the molecules from uniting, and sudden solidification when the loss goes below that point, occur here as before; and here as before, the absence of a period during which the molecules are partially free and gradually losing their freedom, is accompanied by the absence of minor re-arrangements.

Mark, conversely, what happens when the concentration is slow. A gaseous mass losing its heat and undergoing a consequent decrease of bulk, undergoes also many simultaneous changes. The great quantity of molecular motion contained in it, giving great molecular freedom, renders every part sensitive to every incident force; and, as a result, its parts have various motions besides that implied by their progressing integration. Indeed these secondary motions which we know as currents, are so conspicuous as quite to subordinate the primary motion. Suppose that, presently, the loss of molecular motion has reached the point at which the gaseous state can no longer be maintained, and condensation follows. Under their more closely-united form, the parts of the aggregate display, to a considerable degree, the same phenomena as before. The molecular motion and accompanying molecular mobility implied by the liquid state, permit easy re-arrangement; and hence there go on rapid and marked changes in the relative positions of parts — local streams produced by slight disturbing forces. But now, if instead of a mobile liquid we take a sluggish one such as molten pitch or asphalte, what happens as the molecular motion decreases? The liquid thickens — its parts cease to be movable among one another with ease; and the transpositions caused by feeble incident forces become slow. Little by little the currents are stopped, but the mass still continues modifiable by stronger incident forces. Gravitation makes it bend or spread out when not supported on all sides, and it may easily be indented. As it cools, it continues to grow stiffer; and eventually, further loss of heat renders it quite hard: its parts are no longer appreciably re-arrangeable by any save violent actions.

Among inorganic aggregates, then, secondary redistributions accompany the primary re-distributions where this is gradual. During the gaseous and liquid stages, the secondary re-distributions, rapid and extensive as they are, leave no traces: the molecular mobility being such as to negative the fixed arrangement of parts we call structure. On approaching solidity we arrive at a plastic condition in which re-distributions can still be made, though much less easily; and in which they have a certain persistence — a persistence which can, however, become decided only where solidification stops further re-distribution.

Here we see what are the conditions under which Evolution becomes compound, while we see how the compounding of it can be carried far only in cases more special than any hitherto contemplated; since, on the one hand, extensive secondary re-distributions are possible only where there is a great quantity of contained motion, and, on the other hand, such re-distributions can have permanence only where the contained motion has become small: opposing conditions which seem to negative any large amount of permanent secondary re-distribution.

§103. And now we are in a position to see how these apparently contradictory conditions are reconciled. We shall appreciate the peculiarity of the aggregates classed as organic, in which Evolution becomes so high; and shall see that this peculiarity consists in the combination of matter into forms embodying enormous amounts of motion at the same time that they have a great degree of concentration.

For notwithstanding its semi-solid consistence, organic matter contains molecular motion locked up in each of the ways above contemplated separately. Let us note its distinctive traits. Three out of its four chief components are gaseous; and in their uncombined states these gases united in it have so much molecular motion that they are condensible only with extreme difficulty. Hence it is to be inferred that the proteid-molecule concentrates an immense amount of motion in a small space. And since many equivalents of these gaseous elements unite in one of these proteid-molecules, there must be in it a large quantity of relative motion in addition to that which the ultimate atoms possess. Moreover, organic matter has the peculiarity that its molecules are aggregated into the colloid and not into the crystalloid arrangement; forming, as is supposed, clusters of clusters which have movements in relation to one another. Here, then, is a further mode in which molecular motion is included. Yet again, these compounds of which the essential parts of organisms are built, are nitrogenous; and we have lately seen it to be a peculiarity of nitrogenous compounds that, instead of giving out heat during their formation, they absorb heat. To all the molecular motion possessed by gaseous nitrogen, is added more motion; and the whole is concentrated in semi-solid protein. Organic aggregates are very generally distinguished, too, by having much insensible motion in a free state — the motion we call heat. Though in many cases the quantity of this contained insensible motion is inconsiderable, in other cases a temperature much above that of the environment is constantly maintained. Once more, there is the vast quantity of motion embodied in the water that permeates organic matter. It is this which, giving to the water its high molecular mobility, gives mobility to the organic molecules partially suspended in it; and preserves that plastic state which so greatly facilitates re-distribution.

These several statements yield no adequate idea of the extent to which living organic substance is thus distinguished from other substances having like sensible forms of aggregation. But some approximation to such an idea may be obtained by contrasting the bulk occupied by this substance, with the bulk which its constituents would occupy if uncombined. An accurate comparison cannot be made in the present state of science. What expansion would occur if the constituents of the nitrogenous compounds could be divorced without adding motion from without, is too complex a question to be answered. But respecting the constituents of that which forms four-fifths of the weight of an ordinary animal — its water — a tolerably definite answer can be given. Were the oxygen and hydrogen of water to lose their affinities, and were no molecular motion supplied to them beyond that contained in water at blood-heat, they would assume a volume twenty times that of the water.* Whether protein under like conditions would expand in a greater or a less degree, must remain an open question; but remembering the gaseous nature of three out of its four chief components, remembering the above-named peculiarity of nitrogenous compounds, remembering the high multiples and the colloidal form, we may conclude that the expansion would be great. We shall not be wrong, therefore, in saying that the elements of the human body if suddenly disengaged from one another, would occupy far more than a score times the space they do: the movements of their molecules would compel this wide diffusion. Thus the essential characteristic of living organic matter, is that it unites this large quantity of contained motion with a degree of cohesion which permits temporary fixity of arrangement.

<* I am indebted for this result to Dr. [afterwards Sir] Edward Frankland, who has been good enough to have the calculation made for me.>

§104. Besides seeing that organic aggregates differ from other aggregates, alike in the quantity of motion they contain and the amount of re-arrangement of parts which accompanies the progressive integration; we shall see that among organic aggregates themselves, differences in the quantities of contained motion are accompanied by differences in the amounts of re-distribution.

The contrasts among organisms in chemical composition yield us the first illustration. Animals are distinguished from plants by their far greater amOunts of structure, as well as by far greater rapidity with which changes go on in them; and, in comparison with plants, animals contain immensely larger proportions of those nitrogenous molecules in which so much motion is locked up. So, too, is it with the contrasts between the different parts of each animal. Though certain nitrogenous parts, as cartilage, are stable and inert, yet the parts in which secondary re-distributions have gone on, and are ever going on, most actively, are those mainly formed of highly-compounded nitrogenous molecules; while parts which, like deposits of fat, consist of relatively-simple molecules, that are non-nitrogenous, are seats of but little structure and but little change.

We find proof, too, that the continuance of the secondary re-distributions by which organic aggregates are distinguished depends on the presence of that locked-up motion which gives mobility to the water diffused through them; and that, other things equal, there is a direct relation between the amount of re-distribution and the amount of contained water. The evidences may be put in three groups. There is the familiar fact that a plant has its formative changes arrested by cutting off the supply of water: the primary redistribution continues — it withers and shrinks or becomes more integrated — but the secondary re-distributions cease. There is the less familiar fact that the like result occurs in animals — occurs, indeed, after a relatively smaller diminution of water. Certain of the lower animals furnish additional proofs. The Rotifera may be rendered apparently lifeless by desiccation, and will yet revive if wetted. When the African rivers it inhabits are dried up the Lepidosiren remains torpid in the hardened mud until return of the rainy season brings water. Humboldt states that during the summer drought, the alligators of the Pampas lie buried in a state of suspended animation beneath the parched surface, and struggle up out of the earth as soon as it becomes humid. The history of each organism teaches the same thing. The young plant, just putting its head above the soil, is more succulent than the adult plant; and the amount of transformation going on in it is relatively greater. In that portion of an egg which displays the formative processes during the early stages of incubation, the changes of arrangement are more rapid than those which an equal portion of the body of a hatched chick undergoes. As may be inferred from their respective powers to acquire habits and aptitudes, the structural modifiability of a child is greater than that of an adult; and the structural modifiability of a young man is greater than that of an old man: contrasts which are associated with contrasts in the densities of the tissues; since the ratio of water to solid matter diminishes with advancing age. And then we have this relation repeated in the contrasts between parts of the same organism. In a tree, structural changes go on rapidly at the ends of shoots, where the ratio of water to solid matter is very great; while the changes are very slow in the dense and almost dry substance of the trunk. Similarly in animals, we have the contrast between the high rate of change going on in a soft tissue like the brain, and the low rate of change going on in dry non-vascular tissues — hairs, nails, horns, etc.

Other groups of facts prove that the quantity of secondary re-distribution in an organism varies, caeteris paribus, according to the contained quantity of the motion called heat. The contrasts between different organisms, and different states of the same organism, unite in showing this. Speaking generally, the amounts of structure and rates of structural change, are smaller throughout the vegetal kingdom than throughout the animal kingdom; and, speaking generally, the heat of plants is less than the heat of animals. Comparisons of the several divisions of the animal kingdom with one another, disclose parallel relations. Regarded as a whole, vertebrates are higher in temperature than invertebrates; and they are as a whole higher in activity and complexity. Between subdivisions of the Vertebrata themselves, like differences in the degrees of molecular vibration accompany like differences in the degrees of evolution. The least compounded of the Vertebrata are the fishes; and, usually, the heat of fishes is nearly the same as that of the water in which they swim: only some large ones being decidedly warmer. Though we habitually speak of reptiles as cold-blooded, and though they have not much more power than fishes of maintaining a temperature above that of their medium, yet since their medium (which is, in the majority of cases, the air of warm climates) is on the average warmer than the medium inhabited by fishes, the temperature of the class reptiles is higher than that of the class fishes; and we see in them a correspondingly higher complexity. The much more active molecular agitation in mammals and birds, goes along with a considerably greater multiformity of structure and a far greater vivacity. The most instructive contrasts, however, are those occurring in the same organic aggregates at different temperatures. Structural changes in plants vary in rate as the temperature varies. Though light effects those molecular changes causing vegetal growth, yet in the absence of heat, such changes are not effected: in winter there is enough light, but not enough heat. That this is the sole cause of the suspension of growth, is proved by the fact that at the same season, plants contained in hot-houses go on producing leaves and flowers. We see, too, that their seeds, to which light is not simply needless but detrimental, germinate only when the return of a warm season raises the rate of molecular agitation. In like manner the ova of animals, undergoing those changes which produce structure in them, must be kept more or less warm: in the absence of a certain amount of motion among their molecules, the re-arrangement of parts does not go on. Hybernating animals also supply proof that loss of heat carried far, retards extremely the vital transformations. In animals which do not hybernate, as in man, prolonged exposure to intense cold causes extreme sleepiness, which implies a lowered rate of organic changes; and if the loss of heat continues, there comes death, or stoppage of these changes.

Here, then, is an accumulation of proofs. Living aggregates are distinguished by the associated facts, that during integration they undergo remarkable secondary changes which other aggregates do not undergo to anything like the same extent; and that they contain (bulks being supposed equal) immensely greater quantities of motion, locked up in various ways.

§105. The last chapter closed with the remark that while Evolution is always an integration of Matter and dissipation of Motion, it is in most cases much more. And this chapter opened by specifying the conditions under which Evolution is integrative only, or remains simple, and the conditions under which it is something further than integrative, or becomes compound. In illustrating this contrast between simple and compound Evolution, and in explaining how the contrast arises, a vague idea of Evolution in general has been conveyed. Unavoidably, we have to some extent forestalled the full discussion of Evolution about to be commenced.

There is nothing in this to regret. A preliminary conception, indefinite but comprehensive, is needful as an introduction to a definite conception. A complex idea is not communicable directly, by giving one after another its component parts in their finished forms; since if no outline pre-exists in the mind of the recipient these component parts will not be rightly combined. Much labour has to be gone through which would have been saved had a general notion, however cloudy, been conveyed before the distinct and detailed delineation was commenced.

That which the reader has incidentally gathered respecting the nature of Evolution from the foregoing sections, he may thus advantageously use as a rude sketch. He will bear in mind that the total history of every sensible existence is included in its Evolution and Dissolution; which last process we leave for the present out of consideration. He will not forget that whatever aspect of it we are for the moment considering, Evolution is always to be regarded as an integration of Matter and dissipation of Motion, which may be, and usually is, accompanied by other transformations of Matter and Motion. And he will everywhere expect to find that the primary re-distribution ends in forming aggregates which are simple where it is rapid, but which become compound in proportion as its slowness allows the effects of secondary re-distributions to accumulate.

§106. There is much difficulty in tracing out transformations so vast, so varied, and so intricate as those now to be entered upon. Besides having to deal with concrete phenomena of all orders, we have to deal with each group of phenomena under several aspects, no one of which can be fully understood apart from the rest and no one of which can be studied simultaneously with the rest. Already we have seen that during Evolution two great classes of changes are going on together; and we shall presently see that the second of these great classes is re-divisible. Entangled with one another as all these changes are, explanation of any one class or order involves direct or indirect reference to others not yet explained. We can do no more than make the best compromise.

It will be most convenient to devote the next chapter to a detailed account of Evolution under its primary aspect; tacitly recognizing its secondary aspects only so far as the exposition necessitates.

The succeeding two chapters, occupied exclusively with secondary re-distributions, will make no reference to the primary re-distribution beyond that which is unavoidable: each being also limited to one particular trait of the secondary re-distributions.

In a further chapter will be treated a third, and still more distinct, character of the secondary re-distributions.

Chapter 14

The Law of Evolution

§107. Deduction has now to be verified by induction. Thus far the argument has been that all sensible existences must, in some way or other and at some time or other, reach their concrete shapes through processes of concentration; and the facts named have been named merely to clarify the perception of this necessity. But we have not arrived at that unified knowledge constituting Philosophy, until we have seen how existences of all orders do exhibit a progressive integration of Matter and accompanying loss of Motion. Tracing, so far as we may by observation and inference, the objects dealt with by the Astronomer and the Geologist, as well as those which Biology, Psychology, and Sociology treat of, we have to consider what direct proof there is that the Cosmos, in general and in detail, conforms to this law.

Throughout the classes of facts successively contemplated, attention will be directed not so much to the truth that every aggregate has undergone, or is undergoing, integration, as to the further truth that in every more or less separate part of every aggregate, integration has been, or is, in progress. Instead of simple wholes and wholes of which the complexity has been ignored, we have now to deal with wholes as they actually exist — mostly made up of many members combined in many ways. And in them we shall have to trace the transformation under several forms — a passage of the total mass from a more diffused to a more consolidated state; a concurrent similar passage in every portion of it that comes to have a distinguishable individuality; and a simultaneous increase of combination among such individualized portions.

§108. Our Sidereal System by its general form, by its clusters of stars of various degrees of closeness, and by its nebulae in all stages of condensation, gives grounds for suspecting that, generally and locally, concentration is going on. Assume that its matter has been, and still is being, drawn together by gravitation, and we have an explanation of its leading traits of structure — from its solidified masses up to its collections of attenuated flocculi barely discernible by the most powerful telescopes, from its double stars up to such complex aggregates as the nubeculae. Without dwelling on this evidence, however, let us pass to the case of the Solar System.

The belief, so variously supported, that this has had a nebular genesis, is the belief that it has arisen by the integration of matter and concomitant loss of motion. Evolution, under its primary aspect, is illustrated most simply and clearly by this passage of the Solar System from a diffused incoherent state to a consolidated coherent state. While, according to the nebular hypothesis, there has been going on a gradual concentration of the Solar System as an aggregate, there has been a simultaneous concentration of each partially-independent member. The changes of every planet in passing through its stages of nebulous ring, gaseous spheroid, liquid spheroid, and spheroid externally solidified, have in essentials — dissipation of motion and aggregation of matter — paralleled the changes gone through by the general mass; and those of every satellite have done the like. Moreover, at the same time that the matter of the whole, as well as the matter of each partially-independent part, has been thus integrating, there has been the further integration implied by increasing combination among the parts. The satellites of each planet are linked with their primary into a balanced cluster, while the planets and their satellites form with the Sun, a compound group of which the members are more strongly bound together than were the far-spread portions of the nebulous medium out of which they arose.

Even apart from the nebular hypothesis, the Solar System furnishes facts having a like general meaning. Not to make much of the meteoric matter perpetually added to the Earth, and probably to the other planets, as well as, in larger quantities, to the Sun, it will suffice to name two generally-admitted instances. The one is the retardation of comets by the ethereal medium, and the inferred retardation of planets — a process which must in time, as Lord Kelvin argues, bring comets, and eventually planets, into the Sun. The other is the Sun's still-continued loss of motion in the shape of radiated heat; accompanying the still-continued integration of his mass.

§109. To astronomic evolution we pass without break to the evolution which, for convenience, we separate as geologic. The history of the Earth, as traced out from the structure of its crust, carries us back to that molten state which the nebular hypothesis implies; and, as before pointed out (§69), the changes called igneous are accompaniments of the advancing consolidation of the Earth's substance and loss of its contained motion. The general effects and the local effects must be briefly exemplified.

Leaving behind the time when the more volatile elements now existing as solids were kept by the high temperature in a gaseous form, we may begin with the fact that until the Earth's surface had cooled far below red heat, the mass of water at present covering three-fifths of it, must have existed as vapour. This enormous volume of unintegrated liquid became integrated as fast as dissipation of the Earth's contained motion allowed; leaving, at length, a comparatively small portion uncondensed, which would condense but for the unceasing absorption of molecular motion from the Sun. In the formation of the Earth's crust we have a similar change similarly caused. The passage from a thin solid film, everywhere fissured and movable on the subjacent molten matter, to a crust so thick and strong as to be but now and then very slightly dislocated by disturbing forces, illustrates the process. And while, in this superficial solidification, we see under one form how concentration accompanies loss of contained motion, we see it under another form in that diminution of the Earth's bulk implied by superficial corrugation.

Local or secondary integrations have advanced along with this general integration. A molten spheroid merely skinned over with solid matter, could have presented nothing beyond small patches of land and water. Differences of elevation great enough to form islands of considerable size, imply a crust of some rigidity; and only as the crust grew thick could the land be united into continents divided by oceans. So, too, with the more striking elevations. The collapse of a thin layer round its cooling and contracting contents, would throw it into low ridges. The crust must have acquired a relatively great depth and strength before extensive mountain systems of Vast elevation became possible: continued integration of it made possible great local integrations. In sedimentary changes a like progress is inferable. Denudation acting on the small surfaces exposed during early stages, would produce but small local deposits. The collection of detritus into strata of great extent, and the union of such strata into extensive "systems," imply wide surfaces of land and water, as well as subsidences great in both area and depth; so that integrations of this order must have grown more pronounced as the Earth's crust thickened.

§110. Already we have recognized the fact that the evolution of an organism is primarily the formation of an aggregate, by the continued incorporation of matter previously spread through a wider space. Every plant grows by taking into itself elements that were before diffused, and every animal grows by re-concentrating these elements previously dispersed in surrounding plants or other animals. Here it will be proper to complete the conception by pointing out that the early history of a plant or animal, still more clearly than its later history, shows us this fundamental process. For the microscopic germ of each organism undergoes, for a long time, no other change than that implied by absorption of nutriment. Cells embedded in the stroma of an ovarium, become ova by little else than continued growth at the expense of adjacent materials. And when, after fertilization, a more active evolution commences, its most conspicuous trait is the drawing-in, to a germinal centre, of the substance which the ovum contains.

Now, however, our attention must be directed mainly to the secondary integrations which accompany the primary integration. We have to observe how, along with the formation of a larger mass of matter, there goes on a gathering together and consolidation of this matter into parts, as well as a closer combination of the parts. In the mammalian embryo the heart, at first a long pulsating blood-vessel, by-and-by twists upon itself and integrates. The bile-cells constituting the rudimentary liver, do not simply become different from the wall of the intestine in which they at first lie, but, while accumulating, they diverge from it and consolidate into an organ. The anterior portion of the cerebrospinal axis, at first continuous with. the rest, and not markedly distinguished from it, undergoes a union of its rapidly-growing parts; and at the same time the resulting head folds into a mass marked off from the spine. The like process, variously exhibited in other organs, is meanwhile exhibited by the body as a whole; which becomes integrated somewhat in the same way that an outspread handkerchief and its contents become integrated when its edges are drawn in and fastened to make a bundle. Kindred changes go on after birth, and continue even up to old age. In man, that solidification of the bony framework which, during childhood, is seen in the coalescence of portions of the same bone ossified from different centres, is afterwards seen in the coalescence of bones that were originally distinct. The appendages of the vertebrae join with the vertebral centres to which they belong: a change not completed until towards thirty. At the same time the epiphyses, formed separately from the main bodies of their respective bones, have their cartilaginous connexions turned into osseous ones — are fused to the masses beneath them. The component vertebra of the sacrum, which remain separate till about the sixteenth year, then begin to unite; and in ten or a dozen years more their union is complete. Still later occurs the junction of the coccygeal vertebra; and there are some other bony unions which remain unfinished unless advanced age is reached. To which add that the increase of density, going on throughout the tissues at large during life, is the formation of a more fully integrated substance.

The species of change thus illustrated, may be traced in all animals. That mode of it which consists in the union of similar parts originally separate, has been described by Milne-Edwards and others, as exhibited in various Invertebrata; though it does not seem to have been included by them as an essential trait of organic development. We shall, however, see that local integration is an all-important part of this process, when we find it not only in the successive stages passed through by every embryo, but also in ascending from the lower creatures to the higher. As manifested in either way, it goes on both longitudinally and transversely; under which different forms we may conveniently consider it. Of longitudinal integration, the sub-kingdom Annulosa* supplies abundant examples. Its lower members, such as worms and next to them myriapods, are mostly characterized by the great numbers of their segments; reaching in some cases to several hundreds. But in the higher divisions — crustaceans, insects, and arachnids — this number is reduced to twenty-two, thirteen, or even fewer; while, accompanying the reduction, there is a shortening or integration of the whole body, reaching its extreme in the crab and the spider. The significance of these contrasts, as bearing on the doctrine of Evolution, will be clear when it is observed that they are parallel to those which arise during the development of individual annulose animals. The head and thorax of a lobster form one compact box, made by the union of a number of segments which in the embryo were separable. Similarly, the butterfly shows us segments so much more closely united than they were in the caterpillar, as to be, some of them, no longer distinguishable from one another. The Vertebrata again, throughout their successively higher classes, furnish like instances of longitudinal union. In most fishes, and in limbless reptiles, none of the vertebra coalesce. In most mammals and in birds, a variable number of vertebra become fused to form the sacrum; and in the higher apes and in man, the caudal vertebra also lose their separate individualities in a single oscoccygis. That which we may distinguish as transverse integration, is well illustrated among the Annulosa in the development of the nervous system. Leaving out those most degraded forms which do not present distinct ganglia, we find that the lower annulose animals, in common with the larva of the higher, are severally characterized by a double chain of ganglia running from end to end of the body; while in the more perfectly-formed annulose animals, the two chains unite into a single chain. Mr. Newport has described the course of this concentration in insects, and by Rathke it has been traced in crustaceans. During the early stages of the common cray-fish, there is a pair of ganglia to each ring. Of the fourteen pairs belonging to the head and thorax, the three pairs in advance of the mouth consolidate to form the cephalic ganglion or brain. Meanwhile, of the remainder, the first six pairs severally unite in the median line, while the rest remain more or less separate. Of these six double ganglia thus formed, the anterior four coalesce into one mass; the remaining two coalesce into another mass, and then these two masses coalesce. Here longitudinal and transverse integration go on simultaneously and in the highest crustaceans they are both carried still further. The Vertebrata exhibit transverse integration in the development of the generative system. The lowest mammals — the Monotremata — in common with birds, to which they are in many respects allied, have oviducts which towards their lower extremities are dilated into cavities, each imperfectly performing the function of a uterus. "In the Marsupialia there is a closer approximation of the two lateral sets of organs on the median line: for the oviducts converge towards one another and meet (without coalescing) on the median line; so that their uterine dilatations are in contact with each other, forming a true 'double uterus.'... As we ascend the series of 'placental' mammals, we find the lateral coalescence becoming more and complete.... In many of the Rodentia the uterus still remains completely divided into two lateral halves; whilst in others these coalesce at their lower portions, forming a rudiment of the true 'body' of the uterus in the human subject. This part increases at the expense of the lateral 'cornua' in the higher herbivora and carnivora; but even in the lower quadrumana the uterus is somewhat cleft at its summit."†

<* I adhere to this name though of late years the two divisions Annelida and Arthropoda have usurped its place. Their kinship as lower and higher is admitted, and the name is descriptive of both; for the being formed of rings is their most conspicuous structural trait.>

<† Carpenter's Prin. of Comp. Phys., p. 617.>

Under the head of organic integrations, there remain to be noted another class of illustrations. Whether the Annulosa referred to above are or are not originally compound animals, it is unquestionable that there are compound animals among other classes of invertebrates: integration is displayed not within the limits of an individual only but by the union of many individuals. The Salpidae are composite creatures having the shape of chains joined more or less permanently; and Pyrosoma shows us a large number united into a cylinder. Moreover in the Botryllidae the merging of the individualities goes so far that instead of having separate skins they are enclosed within a common skin. Among the Caeienterata integration produces half-fused colonies of types unlike these. There are the branched Hydrozoa in which many individuals form an aggregate in such a way as to have a common system of nutrition, while some of them undertake special functions; and much the same may be said of those compound Actinozoa which are imbedded in the calcareous frameworks we know as corals. And then in certain pelagic types, grouped as Siphonophora, the united individuals, in some cases alike, are in other cases severally transformed in adaptation to various functions; so that the component individuals, assuming the characters of different organs, become practically combined into a single organism.

From this kind of integration we pass to a kind in which the individuals are not physically united but simply associated — are integrated only by their mutual dependence. We may set down two kinds — those which occur within the same species, and those which occur between members of different species. More or less of the gregarious tendency is common among animals; and when it is marked, there is, in addition to simple aggregation, some degree of combination. Creatures that hunt in packs, or that have sentinels, or that are governed by leaders, form bodies partially united by co-operation. Among polygamous mammals and birds this mutual dependence is closer; and the social insects show us still more consolidated assemblages: some of them having their members so united that they cannot live independently How organisms in their totality are mutually dependent, and in that sense integrated, we shall see on remembering — first, that while all animals live directly or indirectly on plants, plants utilize the carbon dioxide excreted by animals; second, that among animals the flesh-eaters cannot exist without the plant-eaters; third, that a large proportion of plants can continue their respective races only by the help of insects. Without detailing the more complex connexions, which Mr. Darwin has so beautifully illustrated, it will suffice to say that the Flora and Fauna in each habitat, constitute an aggregate so far integrated that many of its species die out if placed amid the plants and animals of another habitat. And this integration, too, increases as organic evolution advances.

§111. The phenomena set down in the foregoing paragraph introduce us to others of a higher order, with which they ought, in strictness, to be grouped-phenomena which we may term super-organic. Inorganic bodies present us with certain facts. Additional facts, mostly of a more involved kind, are presented by organic bodies. There remain yet further facts, not presented by any organic body taken singly, but which result from the actions of aggregated organic bodes. Though phenomena of this order are, as we see, foreshadowed among inferior organisms, they become so conspicuous in mankind as socially united, that practically we may consider them to commence here.

In the social organism integrative changes are abundantly exemplified. Uncivilized societies display them when wandering families, such as those of Bushmen, join into tribes of considerable size. A further progress in mass results from the subjugation of weak tribes by strong ones; and in the subordination of their respective chiefs to the conquering chief. Such combinations which, among aboriginal races, are continually being formed and continually broken up, become, among superior races, relatively permanent. If we trace the stages through which our own society, or any adjacent one, has passed, we see this unification from time to time repeated on a larger scale and gaining in stability The consequent establishment of groups of vassals bound to their respective lords; the subsequent subjection of groups of inferior nobles to dukes or earls; and the still later growth of the kingly power over dukes and earls; are so many instances of increasing consolidation. This process slowly completes itself by destroying the original lines of demarcation. And of the European nations it may be further remarked, that in the tendency to form alliances, in the restraining influences exercised by governments over one another, in the system of settling international arrangements by congresses, as well as in the weakening of commercial barriers and the increasing facilities of communication, we see the beginnings of a European federation — a still larger integration that any now established.

But it is not only in these external unions of groups with groups, and of the compound groups with one another, that the general law is exemplified. It is exemplified also in unions which take place internally, as the groups become better organized. There are two orders of these, broadly distinguishable as regulative and operative. A civilized society is made unlike a savage tribe by the establishment of regulative classes-governmental, administrative, military, ecclesiastical, legal, etc., which, while they severally have their bonds of union, constituting them sub-classes, are also held together as a general class by a certain community of privileges, of blood, of education, of intercourse. In some societies, fully developed after their particular types, this consolidation into castes, and this union among the upper castes by separation from the lower eventually grow very decided: to be afterwards rendered less decided, only in cases of social metamorphosis caused by the industrial régime. The integrations seen throughout the operative or industrial organization, later in origin, are not merely of this indirect kind, but they are also direct — they show us physical approach. We have integrations consequent on the growths of adjacent parts performing like functions; as, for instance, the junction of Manchester with its calico-weaving suburbs. We have other integrations which arise when, out of several places producing a particular commodity, one gaining more and more of the business, draws to it masters and workers, and leaves the other places to dwindle; as witness the growth of the Yorkshire cloth-districts at the expense of those in the West of England; or the absorption by Staffordshire of the pottery-manufacture, and the consequent decay of establishments at Derby and elsewhere. We have those more special integrations that arise within the same city; whence result the concentration of corn-merchants about Mark Lane, of civil engineers in Great George Street, of bankers in the centre of the city. Industrial integrations which consist, not in the approximation or fusion of parts, but in the establishment of centres of connexion, are shown in the Bankers' clearing-house and the Railway clearing-house. While of yet another species are those unions which bring into relation dispersed citizens who are occupied in like ways; as traders are brought by the Exchange, and as are professional men by institutes like those of Civil Engineers, Architects, etc.

These seem to be the last of our instances. Having followed up the general law to social aggregates, there apparently remain no other aggregates to which it can apply. This, however, is not true. Among what were above distinguished as super-organic phenomena, there are sundry further groups of remarkable illustrations. Though evolutions of the various products of social activities cannot be said directly to exemplify the integration of matter and dissipation of motion, yet they exemplify it indirectly. For the progress of Language, of Science, and of the Arts, industrial and aesthetic, is an objective register of subjective changes. Alterations of structure in human beings, and concomitant alterations of structure in aggregates of human beings, jointly produce corresponding alterations of structure in all those things which humanity creates. As in the changed impress on the wax, we read a change in the seal; so in the integrations of advancing Language, Science, and Art, we see reflected certain integrations of advancing human structure, individual and social. A section must be devoted to each group.

§112. Among uncivilized races, the many-syllabled names of not uncommon objects, as well as the descriptive character of proper names, show that the words used for the less-familiar things are formed by uniting the words used for the more-familiar things. This process of composition is sometimes found in its incipient stage — a stage in which the component words are temporarily joined to signify some unnamed object, and, from lack of frequent use, do not permanently cohere. But in most inferior languages, the process of "agglutination" has gone far enough to produce some stability in the compound words: there is a manifest integration. How small is this integration, however, in comparison with that reached in well-developed languages, is shown both by the great length of the compound words used for common things and acts, and by the separableness of their elements. Certain North-American tongues illustrate this very well. In a Ricaree vocabulary extending to fifty names of common objects, which in English are nearly all expressed by single syllables, there is not one monosyllabic word. Things so familiar to these hunting tribes as dog and bow, are, in the Pawnee language, ashakish and teeragish; the hand and the eyes are respectively iksheeree and keereekoo. for day the term is shakoorooeeshairet, and for devil it is tsaheekshkakooraiwah. while the numerals are composed of from two syllables up to five, and in Ricaree up to seven. That the great length of these familiar words implies low development, and that in the formation of higher languages out of lower there is a gradual integration, which reduces the polysyllables to dissyllables and monosyllables, is an inference confirmed by the history of our own language. Anglo-Saxon steorra has been in course of time consolidated into English star, mona into moon, and nama into name. The transition through semi-Saxon is clearly traceable. Sunu became in semi-Saxon sune, and in English son; the final e of sune being an evanescent form of the original u. The change from the Anglo-Saxon plural, formed by the distinct syllable as, to our plural formed by the appended consonant s, shows the same thing: smithas in becoming smiths, and endas in becoming ends, illustrate progressive coalescence. So, too does the disappearance of the terminal an in the infinitive mood of verbs; as shown in the transition from the Anglo-Saxon cuman to the semi-Saxon cumme, and to the English come. Moreover the process has been slowly going on, even since what we distinguish as English was formed. In Elizabeth's time, verbs were still frequently pluralized by the addition of en — we tell was we tellen; and in some places this form of speech may even now be heard. In like manner the terminal ed of the past tense, has united with the word it modifies. Burn-ed has in pronunciation become burnt; and even in writing, the terminal t has in some cases taken the place of the ed. Only where antique forms in general are adhered to, as in the church-service, is the distinctness of this inflection still maintained. Further, we see that the compound vowels have been in many cases fused into single vowels. That in bread the e and a were originally both sounded, is proved by the fact that they are still so sounded in parts where old habits linger. We, however have contracted the pronunciation into bred; and we have made like changes in many other common words. Lastly, let it be noted that where the repetition is greatest, the process is carried furthest; as instance the contraction of lord (originally hlaford) into lud in the mouths of barristers; and, still better, the coalescence of God be with you into Good bye.

Besides thus exhibiting the integrative process, Language equally exhibits it throughout all grammatical development. The lowest kinds of human speech, having merely nouns and verbs without inflections, permit no such close union of the elements of a proposition as results when their relations are marked either by inflections or by connective words. Such speech is what we significantly call "incoherent." To a considerable extent, incoherence is seen in the Chinese language. "If, instead of saying I go to London, figs come from Turkey, the sun shines through the air, we said, I go end London, figs come origin Turkey, the sun shines passage air, we should discourse after the manner of the Chinese." From this "aptotic" form, there is a transition, by coalescence, to a form in which the connexions of words are expressed by joining with them certain inflectional words. "In Languages like the Chinese," remarks Dr. Latham, "the separate words most in use to express relation may become adjuncts or annexes." To this he adds the fact that "the numerous inflexional languages fall into two classes. In one, the inflexions have no appearance of having been separate words. In the other, their origin as separate words is demonstrable." From which the inference drawn is, that the "aptotic" languages, by the more and more constant use of adjuncts, gave rise to the "agglutinate" languages, or those in which the original separateness of the inflexional parts can be traced; and that out of these, by further use, arose the "amalgamate" languages, or those in which the original separateness of the inflexional parts can no longer be traced. Strongly corroborative of this inference is the fact that, by such a process, there have grown out of the amalgamate languages, the "anaptotic" languages, of which our own is the best example — languages in which, by further consolidation, inflexions have almost disappeared, while, to express the verbal relations, new kinds of words have been developed. When we see the Anglo-Saxon inflexions gradually lost by contraction during the development of English, and, though to a less degree, the Latin inflexions dwindling away during the development of French, we cannot deny that grammatical structure is modified by integration; and seeing how clearly the earlier stages of grammatical structure are explained by it, we must conclude that it has been going on from the first.

In proportion to the degree of this integration, is the extent to which integration of another order is carried. Aptotic languages are, as already pointed out, necessarily incoherent — the elements of a proposition cannot be completely tied into a whole. But as fast as coalescence produces inflected words, it becomes possible to unite them into sentences of which the parts are so mutually dependent that no considerable change can be made without destroying the meaning. Yet a further stage in this process may be noted. After the development of those grammatical forms which make definite statements possible, we do not at first find them used to express anything beyond statements of a simple kind. A single subject with a single predicate, accompanied by but few qualifying terms, are usually all. If we compare, for instance, the Hebrew scriptures with writings of modern times, a marked difference of aggregation among the groups of words, is visible. In the number of subordinate propositions which accompany the principal one; in the various complements to subjects and predicates; and in the numerous qualifying clauses — all of them united into one complex whole — many sentences in modern compositions exhibit a degree of integration not to be found in ancient ones.

§113. The history of Science presents facts of the same meaning at every step. Indeed the integration of groups of like entities and like relations, constitutes the most conspicuous part of scientific progress. A glance at the classificatory sciences, shows that the confused incoherent aggregations which the vulgar make of natural objects, are gradually rendered complete and compact, and bound up into groups within groups. While, instead of considering all marine creatures as fish, shell-fish, and jellyfish, Zoology establishes among them subdivisions under the heads Vertebrata, Annulosa, Mollusca, Coelenterata, etc.; and while, in place of the wide and vague assemblage popularly described as "creeping things," it makes the specific classes Annelida, Myiiapoda, Insecta, Arachnida; it simultaneously gives to these an increasing consolidation. The several species, genera, and orders of which each consists, are arranged according to their affinities and tied together under common definitions; at the same time that, by extended observation and rigorous criticism, the previously unknown and undetermined forms are integrated with their respective congeners. Nor is the process less clearly displayed in those sciences which have for their subject-matter, not classified objects but classified relations. Under one of its chief aspects, scientific advance is the advance of generalization; and generalizing is uniting into groups all like co-existences and sequences among phenomena. The colligation of many concrete relations into a generalization of the lowest order, exemplifies this process in its simplest form; and it is again exemplified in a more complex form by the colligation of these lowest generalizations into higher ones, and these into still higher ones. Year by year connexions are established among orders of phenomena that appear unallied; and these connexions, multiplying and strengthening, gradually bring the seemingly unallied orders under a common bond. When, for example, Humboldt quotes the observation of the Swiss — "it is going to rain because we hear the murmur of the torrents nearer," — when he recognizes the kinship between this and an observation of his own, that the cataracts of the Orinoco are heard at a greater distance by night than by day — when he notes the analogy between these facts and the fact that the unusual visibility of remote objects is also an indication of coming rain — and when he points out that the common cause of these variations is the smaller hindrance offered to the passage of both light and sound, by media which are comparatively homogeneous, either in temperature or hygrometric state; he helps in bringing under one generalization certain traits of light and certain traits of sound. Experiments having shown that light and sound conform to like laws of reflection and refraction, the conclusion that they are both produced by undulations — though undulations of unlike kinds — gains probability: there is an incipient integration of two classes of facts between which no connexion was suspected in times past. A still more decided integration has been of late taking place between the once independent sub-sciences of Electricity, Magnetism, and Light.

The process will manifestly be carried much further. Such propositions as those set forth in preceding chapters, on "The Persistence of Force," "The Transformation and Equivalence of Forces," "The Direction of Motion," and "The Rhythm of Motion," unite within single bonds phenomena belonging to all orders of existences. And if there is such a thing as that which we here understand by Philosophy, there must eventually be reached a universal integration.

§114. Nor do the industrial and aesthetic Arts fail to supply us with equally conclusive evidence. The progress from small and simple tools, to complex and large machines, is a progress in integration. Among what are classed as the mechanical powers, the advance from the lever to the wheel-and-axle is an advance from a simple agent to an agent made up of several simple ones. On comparing the wheel-and-axle, or any of the mechanical appliances used in early times with those used now, we see that in each of our machines several of the primitive machines are united. A modern apparatus for spinning or weaving, for making stockings or lace, contains not simply a lever, an inclined plane, a screw, a wheel-and-axle, joined together, but several of each — all made into a whole. Again, in early ages, when horsepower and man-power were alone employed, the motive agent was not bound up with the tool moved; but the two have now become in many cases joined together. The firebox and boiler of a locomotive are combined with the machinery which the steam works. A much more extensive integration is seen in every factory. Here numerous complicated machines are all connected by driving shafts with the same steam-engine — all united with it into one vast apparatus.

Contrast the mural decorations of the Egyptians and Assyrians with modern historical paintings, and there is manifest an advance in unity of composition — in the subordination of the parts to the whole. One of these ancient frescoes is made up of figures which vary but little in conspicuousness: there are no gradations of light and shade. The same trait may be noted in the tapestries of medieval days. Representing perhaps a hunting scene, one of these contains men, horses, dogs, beasts, birds, trees, and flowers, miscellaneously dispersed: the living objects being variously occupied, and mostly with no apparent consciousness of one another's proximity. But in paintings since produced, faulty as many of them are in this respect, there is always some co-ordination — an arrangement of attitudes, expressions, lights, and colours, such as to combine the parts into a single scene; and the success with which unity of effect is educed from variety of components, is a chief test of merit.

In music, progressive integration is displayed in more numerous ways. The simple cadence embracing but a few notes, which in the chants of savages is monotonously repeated, becomes, among civilized races, a long series of different musical phrases combined into one whole; and so complete is the integration that the melody cannot be broken off in the middle, nor shorn of its final note, without giving us a painful sense of incompleteness. When to the air, a bass, a tenor, and an alto are added; and when to the different voice-parts there is joined an accompaniment; we see integrations of another order which grow gradually more elaborate. And the process is carried a stage higher when these complex solos, concerted pieces, choruses, and orchestral effects, are combined into the vast ensemble of an oratorio or a musical drama.

Once more the Arts of literary delineation, narrative and dramatic, furnish us with illustrations. The tales of primitive times, like those with which the storytellers of the East still amuse their listeners, are made up of successive occurrences, mostly unnatural, that have no natural connexions: they are but so many separate adventures put together without necessary sequence. But in a good modern work of imagination, the events are the proper products of the characters living under given conditions; and cannot at will be changed in their order or kind, without injuring or destroying the general effect. Further, the characters themselves, which in early fictions play their respective parts without showing how their minds are modified by one another or by the events, are now presented to us as held together by complex moral relations, and as acting and reacting on one another's natures.

§115. Evolution, then, under its primary aspect, is a change from a less coherent form to a more coherent form, consequent on the dissipation of motion and integration of matter. This is the universal process through which sensible existences, individually and as a whole, pass during the ascending halves of their histories. This proves to be a character displayed in those earliest changes which the visible Universe is supposed to have undergone, and in those latest changes which we trace in societies and the products of social life. And, throughout, the unification proceeds in several ways simultaneously.

Alike during the evolution of the Solar System, of a planet, of an organism, of a nation, there is progressive aggregation. This may be shown by the increasing density of the matter already contained in it; or by the drawing into it of matter that was before separate: or by both. But in any case it implies a loss of relative motion. At the same time, the parts into which the mass has divided, severally consolidate in like manner. We see this in that formation of planets and satellites which has gone on along with the progressive concentration of the nebula that originated the Solar System; we see it in that growth of separate organs which advances, pari passu, with the growth of each organism; we see it in that rise of special industrial centres and special masses of population, which is associated with the development of each society. Always more or less of local integration accompanies the general integration. And then, beyond the increased closeness of juxtaposition among the components of the whole, and among the components of each part, there is increase of combination, producing mutual dependence of them. Dimly foreshadowed as this mutual dependence is among inorganic existences, both celestial and terrestrial, it becomes distinct among organic and super-organic existences. From the lowest living forms upwards, the degree of development is marked by the degree in which the several parts constitute a co-operative assemblage — are integrated into a group of organs that live for and by one another. The like contrast between undeveloped and developed societies is conspicuous: there is an ever-increasing coordination of parts. And the same thing holds true of social products, as, for instance, of Science; which has become highly integrated not only in the sense that each division is made up of dependent propositions, but in the sense that the several divisions cannot carry on their respective investigations without aid from one another.

Chapter 15

The Law of Evolution (continued)

§116. Changes great in their amounts and various in their kinds, which accompany those dealt with in the last chapter, have thus far been ignored; or, if tacitly recognized, have not been avowedly recognized. Integration of each whole has been described as taking place simultaneously with integration of each of the parts into which it divides itself. But how comes the whole to divide itself into parts? This is a transformation more remarkable than the passage of the whole from an incoherent to a coherent state; and a formula which says nothing about it omits more than half the phenomena to be formulated.

This larger half of the phenomena we have now to treat. Here we are concerned with those. secondary re-distributions of matter and motion which go on along with the primary re-distribution. We saw that while in very incoherent aggregates, secondary redistributions produce but evanescent results, in aggregates that reach and maintain a certain medium state, neither very incoherent nor very coherent, results of a relatively persistent kind are produced — structural modifications. And our next inquiry must be — What is the universal expression for these structural modifications?

Already an implied answer has been given by the title — Compound Evolution. Already in distinguishing as simple Evolution, that integration of matter and dissipation of motion which is unaccompanied by secondary re-distributions, it has been tacitly asserted that where secondary re-distributions occur complexity arises; the mass, instead of remaining uniform, must have become multiform. The proposition is an identical one. To say that along with the primary re-distribution there go secondary re-distributions, is to say that along with the change from a diffused to a concentrated state, there goes a change from a homogeneous state to a heterogeneous state. The components o f the mass while becoming integrated have also become differentiated.*

<* The terms here used must be understood in relative senses. Since we know of no such thing as absolute diffusion or absolute concentration, the change can never be anything but a change from a more diffused to a less diffused state — from smaller coherence to greater coherence; and, similarly, as no concrete existences present us with absolute simplicity — as nothing is perfectly uniform — as we nowhere find complete homogeneity, the transformation is literally always towards greater complexity or increased multiformity or further heterogeneity. This qualification the reader must bear in mind.>

This, then, is the second aspect under which we have to study Evolution. In the last chapter we contemplated existences of all orders as displaying progressive integration. In this chapter we have to contemplate them as displaying progressive differentiation.

§117. A growing variety of structure throughout our Sidereal System, is implied by the contrasts which indicate aggregation throughout it. We have nebulae that are diffused and irregular, and others that are spiral, annular, spherical. We have groups of stars the members of which are scattered, and groups concentrated in all degrees down to closely-packed globular clusters. We have these groups differing in the numbers of their members, from those containing several thousand stars to those containing but two. Among individual stars there are great contrasts, real as well as apparent, of size; and from their unlike colours, as well as from their unlike spectra, many contrasts among their physical states are inferable. Beyond which heterogeneities in detail there are general heterogeneities. Nebulae are numerous in some regions of the heavens, while in others there are only stars. Here the celestial spaces are almost void of objects, and there we see dense aggregations, nebular and stellar together.

The matter of our Solar System during its integration has become more multiform. The concentrating gaseous spheroid, dissipating its contained molecular motion, acquiring more marked unlikeness of density and temperature between interior and exterior, and leaving behind from time to time annular portions of its mass, underwent differentiations which increased in number and degree, until there was evolved the existing organized group of Sun, planets, and satellites. The heterogeneity of this is variously displayed. There are the immense contrasts between the Sun and the planets, in bulk and in weight; as well as the subordinate contrasts of like kind between one planet and another, and between the planets and their satellites. There is the further contrast between the Sun and the planets in respect of temperature; and there are indications that the planets differ from one another in their proper heats, as well as in the heats which they receive from the sun. Bearing in mind that they also differ in the inclinations of their orbits, the inclinations of their axes, in their specific gravities, and in their physical constitutions, we see how decided is the complexity wrought in the Solar System by those secondary redistributions which have accompanied the primary redistribution.

§118. Passing from illustrations, which, as assuming the nebular hypothesis, must be classed as more or less hypothetical, let us descend to evidence less open to objection.

It is now agreed among geologists that the Earth was once a molten mass. Originally, then, it was comparatively homogeneous in consistence; and, because of the circulation which takes place in heated liquids, must have been comparatively homogeneous in temperature. It must, too, have been surrounded by an atmosphere consisting partly of the elements of air and water, and partly of those various other elements which assume gaseous forms at high temperatures. Cooling by radiation must, after an immense time, have resulted in differentiating the portion most able to part with its heat; namely, the surface. A further cooling, leading to deposition of all solidifiable elements contained in the atmosphere, and then to precipitation of the water, leaving behind the air, must thus have caused a second marked differentiation; and as the condensation commenced on the coolest parts of the surface-namely, about the poles there must so have resulted the first geographical distinctions.

To these illustrations of growing heterogeneity, inferred from known laws, Geology adds an extensive series that have been inductively established. The Earth' s structure has been age after age further complicated by additions to the strata which form its crust; and it has been age after age made more various by the increasing composition of these strata; the more recent of which, formed from the detritus of the more ancient, are many of them rendered highly complex by the mixtures of materials they contain. This heterogeneity has been vastly augmented by the actions of the Earth's nucleus on its envelope; whence have resulted not only many kinds of igneous rocks, but the tilting up of sedimentary strata at all angles, the formation of faults and metallic veins, the production of endless dislocations and irregularities. Again, geologists teach us that the Earth's surface has been growing more varied in elevation — that the most ancient mountain-systems are the smallest, and the Andes and Himalayas the most modern; while, in all probability, there have been corresponding changes in the bed of the ocean. As a consequence of this ceaseless multiplication of differences, we now find that no considerable portion of the Earth's exposed surface, is like any other portion, either in contour, in geologic structure, or in chemical composition.

There has been simultaneously going on a gradual differentiation of climates. As fast as the Earth cooled and its crust solidified, inequalities of temperature arose between those parts of its surface most exposed to the Sun and those less exposed; and thus in time there came to be the marked contrasts between regions of perpetual ice and snow regions where winter and summer alternately reign for periods varying according to the latitude, and regions where summer follows summer with scarcely an appreciable variation. Meanwhile, elevations and subsidences, recurring here and there over the Earth's crust, and producing irregular distributions of land and sea, have entailed various modifications of climate beyond those dependent on latitude; while a yet further series of such modifications has been caused by increased differences of height in the surface, which in sundry places have brought arctic, temperate, and tropical climates to within a few miles of one another. The general results are, that every extensive region has its own meteorological conditions, and that every locality in each region differs more or less from others in those conditions: as also in its structure, its contour, its soil.

Thus between our existing Earth, the phenomena of whose varied crust neither geographers, geologists, mineralogists, nor meteorologists have yet enumerated, and the molten globe out of which it was evolved, the contrast in heterogeneity is striking.

§119. The clearest, most numerous, and most varied illustrations of the advance in multiformity that accompanies the advance in integration, are furnished by living bodies. Distinguished as these are by the great quantity of their contained molecular motion, they exhibit in an extreme degree the secondary re-distributions which contained motion facilitates. The history of every plant and every animal, while it is a history of increasing bulk, is also a history of simultaneously-increasing differences among the parts. This transformation has several aspects.

The chemical composition which is almost uniform throughout the substance of a germ, vegetal or animal, gradually ceases to be uniform. The several compounds, nitrogenous and non-nitrogenous, which were homogeneously mixed, segregate by degrees, become diversely proportioned in diverse places, and produce new compounds by transformation or modification. In plants the albuminous and amylaceous matters which form the substance of the embryo, give origin here to a preponderance of chlorophyll and there to a preponderance of cellulose. Over the parts that are becoming leaf-surfaces, certain of the materials are metamorphosed into wax. In this place starch passes into one of its isomeric equivalents, sugar; and in that place into another of its isomeric equivalents, gum. By secondary change some of the cellulose is modified into wood; while some of it is modified into the allied substance which, in large masses, we call cork. And the more numerous compounds thus arising, initiate further unlikenesses by mingling in unlike ratios. The yelk, or essential part of an animal-ovum, having components which are at first evenly diffused among one another, chemically transforms itself in like manner. Its protein, its fats, its salts, become dissimilarly proportioned in different localities; and multiplication of isomeric forms leads to further mixtures and combinations that constitute minor distinctions of parts. Here a mass darkening by accumulation of hematine, presently dissolves into blood. There fatty and albuminous matters uniting, compose nerve-tissue. At this spot the nitrogenous substance takes on the character of cartilage; and at that, calcareous salts, gathering together in the cartilage, lay the foundation of bone. All these chemical differentiations slowly become more marked and more numerous.

Simultaneously arise contrasts of minute structure. Distinct tissues take the place of matter that had previously no recognizable unlikenesses of parts; and each of the tissues first produced undergoes secondary modifications, causing sub-species of tissues. The granular protoplasm of the vegetal germ, equally with that which forms the unfolding point of every shoot, gives origin to cells that are at first alike. Some of these, as they grow, flatten and unite by their edges to form the outer layer. Others lengthen, and at the same time join together in bundles to lay the foundation of woody-fibre. Before much elongating, certain of these cells show a breaking-up of the lining deposit, which, during elongation, becomes a spiral thread, or a reticulated framework, or a series of rings; and by the longitudinal union of cells so lined, vessels are formed. Meanwhile each of these differentiated tissues is re-differentiated: instance that constituting the essential part of a leaf, the upper stratum of which is composed of chlorophyll-cells remaining closely packed, while the lower stratum becomes spongy. Of the same general character are the transformations undergone by the fertilized ovum, which, at first a cluster of similar cells, quickly reaches a stage marked by dissimilarity of the cells. More frequently recurring fission of the superficial cells, a resulting smaller size of them, and subsequent union of them into an outer layer, constitute the first differentiation; and the middle area of this layer is rendered unlike the rest by still more active processes of like kind. By such modifications upon modifications, many and various, arise the classes and sub-classes of tissues which, intricately combined one with another, compose organs.

Equally conforming to the law are the changes in general shape and in the shapes of organs. All germs are at first spheres and all limbs are at first buds or mere rounded lumps. From this primordial uniformity and simplicity, there take place divergences, both of the wholes and of the leading parts, towards multiformity of contour and towards complexity of contour. Remove the compactly-folded young leaves that terminate every shoot, and the nucleus is found to be a central knob bearing lateral knobs, one of which may grow into either a leaf, a sepal, a petal, a stamen, or a carpel: all these eventually — unlike parts being at first alike. The shoots themselves also depart from their primitive unity of form; and while each branch becomes more or less different from the rest, the whole exposed part of the plant becomes different from the imbedded part. So, too, is it with the organs of animals. One of the Arthropoda, for instance, has limbs that were originally indistinguishable from one another — composed a homogeneous series; but by continuous divergences there have arisen among them unlikenesses of size and form, such as we see in the crab and the lobster. Vertebrate creatures equally exemplify this truth. The wings and legs of a bird are of similar shapes when they bud-out from the sides of the embryo.

Thus in every plant and animal, conspicuous secondary re-distributions accompany the primary re-distribution. A first difference between two parts; in each of these parts other differences which presently become as marked as the first; and a like multiplication of differences in geometrical progression, until there is reached that complex combination constituting the adult. This is the history of all living things whatsoever. Pursuing an idea which Harvey set afloat, it has been shown by Wolff and Von Baer, that during its development each organism passes from a state of homogeneity to a state of heterogeneity. For a generation this truth has been accepted by biologists.*

<* It was in 1852 that I became acquainted with Von Baer's expression of this general principle. The universality of law had ever been with me a postulate, carrying with it a correlative belief, tacit if not avowed, in unity of method throughout Nature. This statement that every plant and animal, originally homogeneous, becomes gradually heterogeneous, set up a co-ordination among thoughts which were previously unorganized, or but partially organized. It is true that in Social Statics (Part IV, §§12-16), published before meeting with Von Baer's formula, the development of an individual organism and the development of a social organism, are described as alike consisting in advance from simplicity to complexity, and from independent like parts to mutually-dependent unlike parts. But though admitting of extension to other super-organic phenomena, this statement was too special to admit of extension to inorganic phenomena. The great aid tendered by Von Baer's formula arose from its higher abstractness; since, only when organic transformations had been expressed in the most abstract terms, was the way opened for seeing what they had in common with inorganic transformations. The conviction that this process of change gone through by each unfolding organism, is a process gone through by all things, found its first coherent statement in an essay on "Progress: its Law and Cause" which I published in the Westminster Review for April, 1857 — an essay with the first half of which this chapter coincides in substance, and partly in form. In that essay, how ever, as also in the first edition of this work, I fell into the error of supposing that the transformation of the homogeneous into the heterogeneous constitutes Evolution. We have seen that this is not so. It constitutes the secondary re-distribution accompanying the primary re-distribution in that Evolution which we distinguish as compound; or rather is we shill presently see, it constitutes the most conspicuous trait of this secondary re-distribution.>

§120. When we pass from individual forms of life to life at large, and ask whether the same law is seen in the ensemble of its manifestations — whether modern plants and animals have more heterogeneous structures than ancient ones, and whether the Earth's present Flora and Fauna are more heterogeneous than the Flora and Fauna of the past, — we find the evidence so fragmentary that nearly every conclusion is open to dispute. Three-fifths of the Earth's surface being covered by water; a great part of the exposed land being inaccessible to, or untravelled by, the geologist; the most of the remainder having been scarcely more than glanced at; and even familiar portions, as England, having been so imperfectly explored that a new series of strata has been added within these few years; it is clearly impossible to say with any certainty what creatures have, and what have not, existed at any particular period. Considering the perishable nature of many of the lower organic forms, the metamorphosis of many beds of sediment, and the gaps that occur among the rest, we shall see further reason for distrusting our deductions. On the one hand, the repeated discovery of vertebrate remains in strata previously supposed to contain none — of reptiles where only fish were thought to exist, and of mammals where it was believed there were no creatures higher than reptiles; renders it daily more manifest how small is the value of negative evidence. On the other hand, the worthlessness of the assumption that we have found the earliest, or anything like the earliest, organic remains, is becoming equally clear. That the oldest known aqueous formations have been greatly changed by igneous action, and that still older ones have been totally transformed by it, is becoming undeniable. And the fact that sedimentary strata earlier than any we know have been melted up, being admitted, it must also be admitted that we cannot say how far back in time this destruction of sedimentary strata has been going on. For aught we know to the contrary, only the last chapters of the Earth's biological history may have come down to us.

Most inferences must thus be extremely questionable. If a progressionist argues that the earliest known vertebrate remains are those of Fishes, which are the most homogeneous of the Vertebrata; that Reptiles, which are more heterogeneous, are later; and that later still, and more heterogeneous still, are Mammals and Birds; it may be replied that the Palaeozoic deposits, not being estuary deposits, are not likely to contain the remains of terrestrial Vertebrata, which may nevertheless have existed. A like answer may be made to the argument that the vertebrate fauna of the Palaeozoic period, consisting, so far as we know, entirely of Fishes, was less heterogeneous than the modern vertebrate fauna, which includes Reptiles, Birds and Mammals, of multitudinous genera; while a uniformitarian may contend with great show of truth, that this appearance of higher and more varied forms in later geologic eras, was due to progressive immigration — that a continent slowly upheaved from the ocean at a point remote from pre-existing continents, would necessary be peopled from them in a succession like that which our strata display. At the same time the counter-arguments may be proved equally inconclusive. When, to show that there cannot have been a continuous evolution of the more homogeneous organic forms into the more heterogeneous ones, the uniformitarian points to the breaks which occur in the succession of these forms, there is the sufficient answer that current geological changes show us why such breaks must occur, and why, by subsidences and elevations of large areas, there must be produced breaks so immense as those which divide the great geologic epochs. Or again, if the opponent of the development hypothesis cites the facts set forth by Professor Huxley in his lecture on "Persistent Types" — if he points out that "of some two hundred known orders of plants, not one is exclusively fossil," while "among animals, there is not a single totally extinct class; and of the orders, at the outside not more than seven per cent are unrepresented in the existing creation" — if he urges that among these some have continued from the Silurian epoch to our own day with scarcely any change and if he infers that there is a much greater average resemblance between the living forms of the past and those of the present, than consists with the hypothesis; there is still a satisfactory reply, on which in fact Prof. Huxley insists; namely, that we have evidence of a "pre-geologic era" of unknown duration. And, indeed, when we remember that the enormous subsidences of the Silurian period show the Earth's crust to have been approximately as thick then as it is now — when we conclude that the time taken to form so thick a crust, must have been immense as compared with the time which has since elapsed — when we assume, as we must, that during this comparatively immense time the geologic and biologic changes went on at their usual rates; it becomes manifest, not only that the palaeontological records which we find do not negative the theory of evolution, but that they are such as might rationally be looked for.

Moreover, though the evidence suffices neither for proof nor disproof, yet some of its most conspicuous facts support the belief, that the more heterogeneous organisms and groups of organisms, have been evolved from the less heterogeneous ones. The average community of type between the fossils of adjacent strata, and especially the community found between the latest tertiary fossils and creatures now existing, is one of these facts. The discovery in some modern deposits of such forms as the Pataeotherium and Anaplotherium, which, according to Prof. Owen, had a type of structure intermediate between some of the types now existing, is another of these facts. And the comparatively recent appearance of Man, is a third fact of this kind, which possesses still greater significance.* Hence we may say that though our knowledge of past life upon the Earth is relatively small, yet what we have, and what we continually add to it, support the belief that there has been an evolution of the simple into the complex alike in individual forms and in the aggregate of forms.

<* I leave these sentences as they stood when written nearly forty years ago, thinking it better to name in a note the vast amount of confirmatory evidence which has accumulated in the interval, and which renders unassailable the conclusion drawn. In 1862 no one thought it possible that there could be proof of a transition between reptiles and birds; and yet since that time forms unquestionably transitional have been found. Though the indications of many other such kinships, by the discoveries of intercalary forms, have not yet in most cases been followed by proofs of continuous genealogy, yet it is otherwise in the case of the horse, the ancestry of which has been traced. Evidence of descent from a three-toed animal of the Miocene period is considered by Prof. Huxley as conclusive: sceptical and cautious though he is. In his Inaugural Address to the Geological Society in 1870, on "Paleontology and the Doctrine of Evolution." many further illustrations are given of kinships between ancient and modern types. Nowadays, indeed, there is universal agreement among naturalists (a few surviving disciples of Cuvier in France being excepted) that all organic forms have arisen by the superposing of modifications upon modifications: increase in heterogeneity being an average implication.>

§121. Advance from the homogeneous to the heterogeneous is clearly displayed in the progress of the latest and most heterogeneous creature — Man. While the peopling of the Earth has been going on, the human organism has grown more heterogeneous among the civilized divisions of the species; and the species, as a whole, has been made more heterogeneous by the multiplication of races and the differentiation of them from one another. In proof of the first of these statements may be cited the fact that, in the relative development of the limbs, civilized men depart more widely from the general type of the placental mammalia, than do the lowest men. Though often possessing well-developed body and arms, the Papuan has very small legs: thus reminding us of the man-like apes, in which there is no great contrast in size between the hind and fore limbs. But in the European, the greater length and massiveness of the legs has become marked — the fore and hind limbs are relatively more heterogeneous. The greater ratio which the cranial bones bear to the facial bones, illustrates the same truth. Among the Vertebrata in general, evolution is marked by an increasing heterogeneity in the vertebral column, and especially in the components of the skull: the higher forms being distinguished by the relatively larger size of the bones which cover the brain, and the relatively smaller size of those which form the jaws, etc. Now this trait, which is stronger in Man than in any other creature, is stronger in the European than in the savage. Moreover, from the greater extent and variety of faculty he exhibits, we may infer that the civilized man has also a more complex or heterogeneous nervous system than the uncivilized man; and, indeed, the fact is in part visible in the increased ratio which his cerebrum bears to the subjacent ganglia. If further elucidation be needed, every nursery furnishes it. In the infant European we see sundry resemblances to the lower human races; as in the flatness of the alae of the nose, the depression of its bridge, the divergence and forward opening of the nostrils, the form of the lips, the absence of a frontal sinus, the width between the eyes, the smallness of the legs. Now as the developmental process by which these traits are turned into those of the adult European, is a continuation of that change from the homogeneous to the heterogeneous displayed during the previous evolution of the embryo; it follows that the parallel developmental process by which the like traits of the barbarous races have been turned into those of the civilized races, has also been a continuation of the change from the homogeneous to the heterogeneous. The truth of the second statement is so obvious as scarcely to need illustration. Every work on Ethnology, by its divisions and subdivisions of races, bears testimony to it. Even were we to admit that Mankind originated from several separate stocks, it would still remain true that as, from each of these stocks, there have sprung many now widely different tribes, which are proved by philological evidence to have had a common origin, the race as a whole is more heterogeneous than it once was. Add to which that we have, in the Anglo-Americans, an example of a new variety arising within these few generations; and that, if we may trust to the descriptions of observers, we are likely soon to have another such in Australia.

§122. On passing from Humanity under its individual form to Humanity as socially embodied, we find the general law still more variously exemplified. The change from the homogeneous to the heterogeneous is displayed equally in the progress of civilization as a whole, and in the progress of every tribe or nation; and it is still going on with increasing rapidity.

Society in its first and lowest stage is a homogeneous assemblage of individuals having like powers and like functions: the only marked difference of function being that which accompanies difference of sex. Every man is warrior, hunter, fisherman, tool-maker, builder; every woman performs the same drudgeries; every family is self-sufficing, and, save for purposes of companionship, aggression, and defence, might as well live apart from the rest. Very early, however, in the course of social evolution, we find an incipient differentiation between the governing and the governed. Some kind of chieftainship soon arises after the advance from the state of separate wandering families to that of a nomadic tribe. The authority of the strongest and cunningest makes itself felt among savages, as in a herd of animals or a posse of schoolboys: especially in war. At first, however, it is indefinite, uncertain; is shared by others of scarcely inferior power; and is unaccompanied by any difference in occupation or style of living: the first ruler kills his own game, makes his own weapons, builds his own hut, and, economically considered, does not differ from others of his tribe. Along with conquests and the massing of tribes, the contrast between the governing and the governed grows more decided. Supreme power becomes hereditary in one family; the head, first military and then political, ceasing to provide for his own wants, is served by others; and he begins to assume the sole office of ruling. At the same time there has been arising a co-ordinate species of government — that of Religion. Ancient records and traditions show that the earliest conquerors and kings came to be regarded as divine personages. The maxims and commands they uttered during their lives were held sacred after their deaths, and were enforced by their divinely-descended successors; who in their turns were promoted to the pantheon of the race, there to be worshipped and propitiated along with their predecessors. For a long time these connate forms of government — civil and religious — remain closely associated. For many generations the king continues to be the chief priest, and the priesthood to be members of the royal race. For many ages religious law continues to contain more or less of civil regulation, and civil law to possess more or less of religious sanction; and even among the most advanced nations these two controlling agencies are by no means completely differentiated from each other. Having a common root with these, and gradually diverging from them, we find yet another controlling agency — that of Manners or ceremonial usages. Titles of honour were originally the names of the god-king; afterwards of God and the king; still later of persons of high rank; and finally came, some of them, to be used between man and man. Forms of complimentary address were at first expressions of propitiation from prisoners to their conqueror, or from subjects to their ruler, either human or divine — expressions that were afterwards used subordinate authorities, and slowly descended into ordinary intercourse. Modes of salutation were once signs of subjection to a victor, afterwards obeisances made before the monarch and used in worship of him when dead. Presently others of the god-descended race were similarly saluted; and by degrees some of the salutations have become the due of all.* Thus, no sooner does the originally homogeneous social mass differentiate into the governed and the governing parts, than this last exhibits an incipient differentiation into religious and secular-Church and State; while at the same time or still earlier there begins to take shape, that less definite species of government which rules our daily intercourse — a species of government which, as we may see in heralds' colleges, in books of the peerage, in masters of ceremonies, is not without a certain embodiment of its own. Each of these kinds of government is itself subject to successive differentiations. In the course of ages, there arises, as among ourselves, a highly complex political organization of monarch, ministers, lords and commons, with their subordinate administrative departments, courts of justice, revenue offices, etc., supplemented in the provinces by municipal governments, county governments, parish or union governments — all of them more or less elaborated. By its side there grows up a highly complex religious organization, with its various grades of officials from archbishops down to sextons, its colleges, convocations, ecclesiastical courts, etc.; to all which must be added the ever-multiplying independent sects, each with its general and local authorities. And simultaneously there is developed a complicated system of customs, manners, and temporary fashions, enforced by society at large, and serving to control those minor transactions between man and man which are not regulated by civil and religious law. Moreover, it is to be observed that this increasing heterogeneity in the governmental appliances of each nation, has been accompanied by an increasing heterogeneity in the governmental appliances of different nations. All peoples are more or less unlike in their political systems and legislation, in their creeds and religious institutions, in their customs and ceremonial usages.

<* For detailed proof see essay on "Manners and Fashion" in Essays, etc., Vol. III.>

Meanwhile there has been going on a differentiation of a more familiar kind; that, namely, by which the mass of the community has been segregated into distinct classes and orders of workers. While the governing part has undergone the complex development above indicated, the governed part has undergone a more complex development, which has resulted in that minute division of labour characterizing advanced nations. It is needless to trace out this progress from its first stages, up through the caste-divisions of the East and the incorporated guilds of Europe, to the elaborate producing and distributing organization existing among ourselves. Political economists have long since described the industrial progress which, through increasing division of labour, ends with a civilized community whose members severally perform different actions for one another; and they have further pointed out the changes through which the solitary producer of any one commodity, is transformed into a combination of producers who, united under a master, take separate parts in the manufacture of such commodity. But there are yet other and higher phases of this advance from the homogeneous to the heterogeneous in the industrial organization of society. Long after considerable progress has been made in the division of labour among the different classes of workers, there is relatively little division of labour among the widely separated parts of the community: the nation continues comparatively homogeneous in the respect that in each district the same occupations are pursued. But when roads and other means of transit become numerous and good, the different districts begin to assume different functions, and to become mutually dependent. The calico-manufacture locates itself in this county, the woollen-manufacture in that; silks are produced here, lace there; stockings in one place, shoes in another; pottery, hardware, cutlery, come to have their special towns; and ultimately every locality grows more or less distinguished from the rest by the leading occupation carried on in it. Nay, more, this subdivision of functions shows itself not only among the different parts of the same nation, but among different nations. That exchange of commodities which free-trade promises so greatly to increase, will ultimately have the effect of specializing, in a greater or less degree, the industry of each people. So that beginning with a primitive tribe, almost if not quite homogeneous in the functions of its members, the progress has been, and still is, towards an economic aggregation of the whole human race; growing ever more heterogeneous in respect of the separate functions assumed by separate nations, the separate functions assumed by the local sections of each nation, the separate functions assumed by the many kinds of producers in each place, and the separate functions assumed by the workers united in growing or making each commodity. And then, lastly, has to be named the vast organization of distributers, wholesale and retail, forming so conspicuous an element in our town-populations, which is becoming ever more specialized in its structure.

§123. Not only is the law thus exemplified in the evolution of the social organism, but it is exemplified in the evolution of all products of human thought and action, whether concrete or abstract, real or ideal. Let us take Language as our first illustration.

The lowest form of language is the exclamation, by which an entire idea is vaguely conveyed through a single sound; as among the lower animals. That human language ever consisted solely of exclamations, and so was strictly homogeneous in respect of its parts of speech, we have no evidence. But that language can be traced down to a form in which nouns and verbs are its only elements, is an established fact. In the gradual multiplication of parts of speech out of these primary ones — in the differentiation of verbs into active and Passive, of nouns into abstract and concrete - in the rise of distinctions of mood, tense, person, or number and case — in the formation of auxiliary verbs, of adjectives, adverbs, pronouns, prepositions, articles — in the divergence of those orders, genera, species, and varieties of parts of speech by which civilized races express minute modifications of meaning; we see a change from the homogeneous to the heterogeneous. And it may be remarked that it is more especially because it has carried this subdivision of functions further than any other language, that the English language is structurally superior. Another process throughout which we may trace the development of language, is the differentiation of words of allied meanings. Philology early disclosed the truth that in all languages words may be grouped into families having each a common ancestry. An aboriginal name, applied indiscriminately to each member of an extensive and ill-defined class of things or actions, presently undergoes modifications by which the chief divisions of the class are expressed. These several names springing from the primitive root, themselves become the parents of other names still further modified. And by the aid of those systematic modes, which presently arise, of making derivatives and forming compounds expressing still smaller distinctions, there is finally developed a tribe of words so heterogeneous in sound and meaning, that to the initiated it seems incredible they should have had a common origin. Meanwhile, from other roots there are being evolved other such tribes, until there results a language of a hundred thousand different words, signifying as many different objects, qualities, acts. Yet another way in which language advances from the homogeneous to the heterogeneous, is by the multiplication of languages. Whether, as Max Müller and Bunsen think, all languages have grown from one stock, or whether, as some philologists say, they have grown from two or more stocks, it is clear that since large families of languages, as the Indo-European, are of one parentage, there have arisen multiplied kinds through a process of continuous divergence. The diffusion over the Earth's surface which has led to differentiation of the race, has simultaneously led to differentiation of its speech: a truth which we see further illustrated in each country by the dialects found in separate districts. Thus linguistic changes conform to the general law, alike in the evolution of languages, in the evolution of families of words, and in the evolution of parts of speech. If in our conception of language we include not its component words only but those combinations of them by which distinct ideas are conveyed — namely sentences — we have to recognize one more aspect of its progress from homogeneity to heterogeneity which has accompanied the progress in integration. Rude speech consists of simple propositions having subjects and predicates indefinitely linked; and anything like a complex meaning is conveyed by a succession of such propositions connected only by juxtaposition. Even in the speech of comparatively developed peoples, as the Hebrews, we find very little complexity. Compare a number of verses from the Bible with some paragraphs from a modern writer, and the increase in heterogeneity of structure is very conspicuous. And beyond the fact that many of our ordinary sentences are by the supplementary clauses, secondary propositions, and qualifying phrases they contain made relatively involved, there is the fact that there is great variety among the sentences in a page: now long, now short, now formed in one way, now in another, so that a double progress in heterogeneity in the style of composition is displayed.

On passing from spoken to written language, we come upon several classes of facts, having similar implications. Written language is connate with Painting and Sculpture; and at first all three are appendages of Architecture, and have a direct connexion with the early form of settled government — the theocratic. Merely noting the fact that sundry wild races, as the Australians and the tribes of South Africa, are given to depicting personages and events on the walls of caves, which are probably regarded as sacred places, let us pass to the case of the Egyptians. Among them, as also among the Assyrians, we see mural paintings used to decorate the temple of the god and the palace of the king (which were, indeed, originally identical); and as such they were governmental appliances in the same sense that stage-pageants and religious feasts were. Further, they were governmental appliances in virtue of representing the worship of the god, the triumphs of the god-king, the submission of his subjects, and the punishment of the rebellious. And yet again they were governmental, as being the products of an art reverenced by the people as a sacred mystery. From the constant use of this pictorial representation, there grew up the but slightly-modified practice of picture-writing — a practice which was found still extant among the Mexicans at the time they were discovered. By abbreviations analogous to those still going on in our own language, the most familiar of these pictured figures were successively simplified; and ultimately there grew up symbols, most of which had but distant resemblances to the things for which they stood. The inference that the hieroglyphics of the Egyptians thus arose, is confirmed by the fact that the picture-writing of the Mexicans was found to have given birth to a like family of ideographic forms; and among them, as among the Egyptians, these had been partially differentiated into the kuriological or imitative, and the tropical or symbolic: which were, however, used together in the same record. In Egypt, written language underwent a further differentiation, resulting in the hieratic and the epistolographic or enchorial: both derived from the original hieroglyphic. At the same time for proper names, which could not be otherwise expressed, phonetic symbols were employed; and though the Egyptians never achieved complete alphabetic writing, yet it can scarcely be doubted that among other peoples phonetic symbols, occasionally used in aid of ideographic ones, were the germs out of which alphabetic writing arose. Once having become separate from hieroglyphics, alphabetic writing itself underwent numerous differentiations — multiplied alphabets were produced: between most of which, however, connexions can still be traced. And in each civilized nation there have now grown up, for the representation of one set of sounds, several sets of written signs, used for distinct purposes. Finally, through a yet more important differentiation came printing; which, uniform in kind as it was at first, has since become multiform.

§124. While written language was passing through its earlier stages of development, the mural decoration which formed its root was being differentiated into Painting and Sculpture. The gods, kings, men, and animals represented, were originally marked by indented outlines and coloured. In most cases these outlines were of such depth, and the object they circumscribed so far rounded, as to form a species of work intermediate between intaglio and bas-relief. In other cases we see an advance upon this: the spaces between the figures being chiselled out, and the figures themselves appropriately tinted, a painted bas-relief was produced. The restored Assyrian architecture at Sydenham exhibits this style of art carried to greater perfection: the persons and things represented, though still barbarously coloured, are carved with more truth and in greater detail; and in the winged lions and bulls used for the angles of gateways, we see advance towards a completely sculptured figure; which, nevertheless, is still coloured and still forms part of the building. But though in Assyria the production of a statue proper seems to have been little, if at all, attempted, we may trace in Egyptian art the gradual separation of the sculptured figure from the wall. While a walk through the collection in the British Museum will afford an opportunity of observing transitions, it will bring into view much evidence that the independent statues were derived from bas-reliefs: newly all of them not only display that lateral attachment of the arms with the body which is a characteristic of bas-relief, but have the back of the statue united from head to foot with a block which stands in place of the original wall. Greece repeated the leading stages of this progress. As in Egypt and Assyria, these twin arts were at first united with each other and with their parent, Architecture; and were aids of Religion and Government. On the friezes of Greek temples, we see coloured bas-reliefs representing sacrifices, battles, processions, games — all in some sort religious. On the pediments we see painted sculptures partially united with the tympanum, and having for subjects the triumphs of gods or heroes. Even when we come to statues that are definitely separated from the buildings to which they pertain, we still find them coloured; and only in the later periods of Greek civilization, does the differentiation of painting from sculpture appear to have become complete. In Christian art there occurred a parallel re-genesis. All early paintings and sculptures throughout Europe were religious in subject — represented Christs, crucifixions, virgins, holy families, apostles, saints. They formed integral parts of church architecture, and were among the means of exciting worship: as in Roman Catholic countries they still are. Moreover, the early sculptures of Christ on the cross, of virgins, of saints, were coloured; and it needs but to call to mind the painted madonnas and crucifixes still abundant in continental churches, to perceive the significant fact that painting and sculpture continue in closest connexion with each other, where they continue in closest connexion with their parent. Even when Christian sculpture become separate from painting, it was still at first religious and governmental in its subjects — was used for tombs in churches and statues of saints and kings; while, at the same time, painting, where not purely ecclesiastical, was applied to the decoration of palaces, and after representing royal personages, was almost wholly devoted to sacred legends. Only in modern times have painting and sculpture become entirely secular arts. Only within these few centuries has painting been divided into historical, landscape, marine, architectural, animal, still-life, etc., and sculpture grown heterogeneous in respect of the variety of real and ideal subjects with which it occupies itself.

Strange as it seems then, all forms of written language, of painting, of sculpture, have a common root in those rude drawings on skins and cavern-walls by which savages commemorated notable deeds of their chiefs, and which, during social progress, developed into the politico-religious decorations of ancient temples and palaces. Little resemblance as they now have, the bust that stands on the console, the landscape that hangs against the wall, and the copy of The Times lying upon the table, are remotely akin. The brazen face of the knocker which the postman has just lifted, is related not only to the woodcuts of the Illustrated London News which he is delivering, but to the characters of the billet-doux which accompanies it. Between the painted window the prayer-book on which its light falls, and the adjacent monument, there is consanguinity. The effigies on our coins, the signs over shops, the figures that fill every ledger, the coat-of-arms outside the carriage-panel, and the placards inside the omnibus, are, in common with dolls, blue-books, and paper-hangings, lineally descended from the sculpture-paintings and picture-writings in which the Egyptians represented and recorded the triumphs and worship of their god-kings. Perhaps no example can be given which more vividly illustrates the multiplicity and heterogeneity of the products that in course of time may arise by successive differentiations from a common stock.

The transformation of the homogeneous into the heterogeneous thus displayed in the separation of Painting and Sculpture from Architecture and from each other, and in the greater variety of subjects they embody, is further displayed in the structure of each work. A modern picture or statue is of far more complex nature than an ancient one. An Egyptian sculpture-fresco represents all its figures as on one plane — that is, at the same distance from the eye; and so is less heterogeneous than a painting that represents them as at various distances. It exhibits all objects as similarly lighted; and so is less heterogeneous than a painting which exhibits different objects, and different parts of each object, as in different degrees of light. It uses scarcely any but the primary colours, and these in their full intensities; and so is less heterogeneous than a painting which, introducing the primary colours but sparingly, employs an endless variety of intermediate tints, each of heterogeneous composition, and differing from the rest not only in quality but in strength. Moreover, these earliest works manifest great uniformity of conception. In ancient societies the modes of representation were so fixed that it was sacrilege to introduce a novelty. In Egyptian and Assyrian bas-reliefs, deities, kings, priests, attendants, winged-figures and animals, are in all cases depicted in like positions, special to each class, holding like implements, doing like things, and with like expression or non-expression of face. If a palm-grove is introduced, all the trees are of the same height, have the same number of leaves, and are equidistant. When water is imitated, each wave is a counterpart of the rest; and the fish, almost always of one kind, are evenly distributed. The beards of the Assyrian kings, gods, and winged-figures, are everywhere similar; as are the manes of the lions, and equally so those of the horses. Hair is represented throughout by one form of curl. The king's beard is built up of compound tiers of uniform curls, alternating with twisted tiers placed transversely and arranged with perfect regularity; and the terminal tufts of the bulls' tails are represented in exactly the same manner. Without tracing out analogous traits in early Christian art, in which, though less striking, they are still visible, the advance in heterogenity will be sufficiently manifest on remembering that in the pictures of our own day the composition is endlessly varied; the attitudes, faces, expressions, unlike; the subordinate objects different in size, form, position, texture. Or, if we compare an Egyptian statue, seated upright on a block, with hands on knees, fingers outspread and parallel, eyes looking straight forward, and the two sides perfectly symmetrical, with a statue of the advanced Greek or the modern school, which is asymmetrical in respect of the position of the head, the body, the limbs, the arrangement of the hair, dress, appendages, and in its relations to neighbouring objects, we see the change from the homogeneous to the heterogeneous clearly manifested.

§125. In the co-ordinate origin and gradual differentiation of Poetry, Music, and Dancing, we have another series of illustrations. Rhythm in speech, rhythm in sound, and rhythm in motion, were in the beginning, parts of the same thing. Among existing barbarous tribes we find them still united. The dances of savages are accompanied by some kind of monotonous chant, the clapping of hands, the striking of rude instruments: there are measured movements, measured words, and measured tones; and the whole ceremony, usually having reference to war or sacrifice, is of governmental character. The early records of the historic races similarly show these three forms of metrical action united in religious festivals. In the Hebrew writings we read that the triumphal ode composed by Moses on the defeat of the Egyptians, was sung to an accompaniment of dancing and timbrels. The Israelites danced and sung "at the inauguration of the golden calf. And as it is generally agreed that this representation of the Deity was borrowed from the mysteries of Apis, it is probable that the dancing Was copied from that of the Egyptians on those occasions." There was an annual dance in Shiloh on the sacred festival; and David danced before the ark. Again, in Greece the like relation existed: the original type being there, as probably in other cases, a simultaneous chanting and mimetic representation of the achievements of the god. The Spartan dances were accompanied by hymns; and in general the Greeks had "no festivals or religious assemblies but what were accompanied with songs and dances" — both of them being forms of worship used before altars. Among the Romans, too, there were sacred dances: the Salian and Lupercalian being named as of that kind. Even in the early Christian church, dances in the choir at festivals, occasionally led by bishops, were among the forms of worship, and in some places continued down to the 18th century. The incipient separation of these once united arts from each other and from religion, was early visible in Greece. Probably diverging from dances partly religious, partly warlike, as the Corybantian, came the war-dances proper, of which there were various kinds; and from these resulted secular dances. Meanwhile Music and Poetry, though still joined, came to have an existence separate from dancing. The primitive Greek poems, religious in subject, were not recited but chanted; and though at first the chant of the poet was accompanied by the dance of the chorus, it ultimately grew into independence. Later still, when the poem had been differentiated into epic and lyric — when it became the custom to sing the lyric and recite the epic-poetry proper was born. As, during the same period, musical instruments were being multiplied, we may presume that music came to have an existence apart from words. And both of them were beginning to assume other forms than the religious. Facts having like implications might be cited from the histories of later times and peoples: as the practices of our Anglo-Saxon "gleemen" and Celtic bards, who sang to the harp heroic narratives versified by themselves to music of their own composition: thus uniting the now separate offices of poet, composer, vocalist, and instrumentalist. The common origin and gradual differentiation of Dancing, Poetry, and Music is thus sufficiently manifest.

Besides being displayed in the separation of these arts from one another and from religion, growing heterogeneity is also displayed in the multiplied differentiations which each of them afterwards undergoes. Just referring to the numberless kinds of dancing that have, in course of time, come into use, and to the progress of poetry, as seen in the development of the various forms of metre, of rhyme, and of general organization, let us confine our attention to music as a type of the group. As argued by Dr. Burney, and as implied by the customs of extant savages, the first musical instruments were percussive-sticks, calabashes, tom-toms — and were used simply to mark the time of the dance. So, too, the vocal music of various semi-civilized races consists of simple phrases endlessly reiterated. In this constant repetition of the same sounds we see music in its most homogeneous form. The Egyptians had a lyre with three strings. The early lyre of the Greeks had four, constituting their tetrachord. In course of some centuries lyres of seven and eight strings came to be employed. And, by the expiration of a thousand years, they had advanced to their "great system" of the double octave. Through all which changes of course arose a greater heterogeneity of melody or rather recitative. Simultaneously came into use the different modes — Dorian, Ionian, Phrygian, AEolian, and Lydian — answering to our keys; and of these there were ultimately fifteen. As yet, however, there was but little heterogeneity in the time of their music. Instruments being used merely to accompany the voice, the vocal music being completely subordinated to words, — the singer being also the poet, chanting his own compositions and making the lengths of his notes agree with the feet of his verses — there unavoidably arose a tiresome uniformity of measure which, as Dr. Burney says, "no resources of melody could disguise." Lacking the complex rhythm obtained by our equal bars and unequal notes, the only rhythm was that produced by the quantity of the syllables, and was of necessity monotonous. And further, the chant thus resulting being like recitative, was much less differentiated from ordinary speech than is our modern song. Nevertheless, considering the extended range of notes in use, the variety of modes, the occasional variations of time consequent on changes of metre, and the multiplication of instruments, we see that music had, towards the close of Greek civilization, attained to considerable heterogeneity: not indeed as compared with our music, but as compared with that which preceded it. As yet, however, there existed nothing but serial combinations of notes (for so we must call them since they were not melodies in our sense): harmony was unknown. It was not until Christian church-music had reached some development, that music in parts was evolved; and then it came into existence through an unobtrusive differentiation. The practice which led to it was the employment of two choirs singing alternately the same air. Afterwards it became the habit (possibly first suggested by a mistake) for the second choir to commence before the first had ceased: thus producing a fugue. With the simple airs then in use, a partially harmonious fugue might not improbably result; and a very partially harmonious fugue satisfied the ears of that age, as we know from still preserved examples. The idea having once been given, the composing of airs productive of fugal harmony would naturally grow up; as in some way it did grow up out of this alternate choir-singing. And from the fugue to concerted music of two, three, four, and more parts, the transition was easy. Without pointing out in detail the increasing complexity that resulted from introducing notes of various lengths, from the multiplication of keys, from the use of accidentals, from varieties of time, from modulations and so forth, it needs but to contrast music as it is with music as it was, to see how immense is the increase of heterogeneity. We see this also if, looking at music in its ensemble, we enumerate its many different genera and species — if we consider the divisions into vocal, instrumental, and mixed; and their subdivisions into music for different voices and different instruments — if we observe the many forms of sacred music, from the simple hymn, the chant, the canon, motet, anthem, etc., up to the oratorio; and the still more numerous forms of secular music, from the ballad up to the serenata, from the instrumental solo up to the symphony. Again, the same truth is seen on comparing any one sample of aboriginal music with a sample of modern music — even an ordinary song for the piano; which we find to be relatively very heterogeneous, not only in respect of varieties in the intervals and in the lengths of the notes, the number of different notes sounding at the same instant in company with the voice, and the variations of strength with which they are sounded and sung, but in respect of the changes of key, the changes of time, the changes of timbre of the voice, and the many other modifications of expression. While between the old monotonous dance-chant and a grand opera of our own day, the contrast in heterogeneity is so extreme that it seems scarcely credible that the one is the ancestor of the other.

§126. Many further illustrations of the general law throughout social products might be detailed. Going back to the time when the deeds of the god-king, chanted and mimetically represented in dances before his altar, were further narrated in picture-writings on the walls of temples and palaces, and so constituted a rude history, we might trace the development of Literature through phases in which, as in the Hebrew Scriptures, it presents in one work, theology, cosmogony, history, biography, civil laws, ethics, poetry; through other phases in which, as in the Iliad, the religious, martial, historical, the epic, dramatic, and lyric elements are similarly commingled; down to its present heterogeneous development, in which its divisions and subdivisions are so numerous and varied as to defy complete classification. Or we might track the unfolding of Science; beginning with the era in which it was not yet differentiated from Art, and was, in union with Art, the handmaid of Religion; passing through the era in which the sciences were so few and rudimentary, as to be simultaneously cultivated by the same philosophers; and ending with the era in which the genera and species are so multitudinous that few can enumerate them, and no one can adequately grasp even one genus. Or we might do the like with Architecture, with the Drama, with Dress. But doubtless the reader is already weary of illustrations, and my promise has been amply fulfilled. The advance from the simple to the complex through successive modifications upon modifications, is seen alike in the earliest changes of the Heavens to which we can reason our way back, and in the earliest changes we can inductively establish; it is seen in the geologic and climatic evolution of the Earth, of every individual organism on its surface and in the aggregate of organisms; it is seen in the evolution of Humanity, whether contemplated in the civilized man, or in the assemblage of races; it is seen in the evolution of Society, in respect alike of its political, its religious, and its economical organization; and it is seen in the evolution of those countless concrete and abstract products of human activity, which constitute the environment of our daily life. From the remotest past which Science can fathom, up to the novelties of yesterday, an essential trait of Evolution has been the transformation of the homogeneous into the heterogeneous.

§127. So that the general formula arrived at in the last chapter needs supplementing. It is true that Evolution, under its primary aspect, is a change from a less coherent state to a more coherent state, consequent on the dissipation of motion and integration of matter; but this is far from being the whole truth. Along with a passage from the coherent to the incoherent, there goes on a passage from the uniform to the multiform. Such, at least, is the fact wherever Evolution is compound; which it is in the immense majority of cases. While there is a progressing concentration of the aggregate, caused either by the closer approach of the matter within its limits, or by the drawing in of further matter, or by both; and while the more or less distinct parts into which the aggregate divides and subdivides are also severally concentrating; these parts are simultaneously becoming unlike — unlike in size, or in form, or in texture, or in composition, or in several or all of these. The same process is exhibited by the whole and by its members. The entire mass is integrating, and at the same time differentiating from other masses; while each member of it is also integrating and at the same time differentiating from other members.

Our conception, then, must unite these characters. As we now understand it, Evolution is definable as a change from an incoherent homogeneity to a coherent heterogeneity, accompanying the dissipation of motion and integration of matter.

Chapter 16

The Law of Evolution (continued)

§128. But does this generalization express the whole truth? Does it include everything essentially characterizing Evolution and exclude everything else? Does it comprehend all the phenomena of secondary redistribution which Compound Evolution presents, without comprehending any other phenomena? A critical examination of the facts will show that it does neither.

Changes from the less heterogeneous to the more heterogeneous, which are not included in what we here call Evolution, occur in every local disease. In a morbid growth we see a new differentiation. Whether this morbid growth be, or be not, more heterogeneous than the tissues in which it is seated, is not the question. The question is whether the organism as a whole is, or is not, rendered more heterogeneous by the addition of a part unlike every pre-existing part, in form, or composition, or both. To this question there can be none but an affirmative answer. Again, the earlier stages of decomposition in a dead body involve increase of heterogeneity. Supposing the chemical changes to commence in some parts sooner than in others, as they commonly do, and to affect different tissues in different ways, as they must, it seems clear that the entire body, made up of undecomposed parts and parts decomposed in various modes and degrees, has become more heterogeneous than it was. Though grater homogeneity will be the eventual result, the immediate result is certainly not Evolution. Other instances are furnished by social disorders and disasters. A rebellion which, while leaving some provinces undisturbed, develops itself here in secret societies, there in public demonstrations, and elsewhere in actual conflicts, necessarily renders the society, as a whole, more heterogeneous. Or when a dearth causes commercial derangement with its entailed bankruptcies, closed factories, discharged operatives, food-riots, incendiarisms; it is manifest that as a large part of the community retains its ordinary organization displaying the usual phenomena, these new phenomena must be regarded as adding to the complexity previously existing. But such changes, so far from constituting further Evolution, are steps towards Dissolution.

So that the definition arrived at in the last chapter is an imperfect one. The changes above instanced as coming within the formula as it now stands, are so obviously unlike the rest, that the inclusion of them implies some distinction hitherto overlooked. Such further distinction we have now to supply.

§129. At the same time that Evolution is a change from the homogeneous to the heterogeneous, it is a change from the indefinite to the definite. Along with an advance from simplicity to complexity, there is an advance from con fusion to order — from undetermined arrangement to determined arrangement. Development, no matter of what kind, exhibits not only a multiplication of unlike parts, but an increase in the clearness with which these parts are marked off from one another. And this is the distinction sought. For proof, it needs only to reconsider the instances given above. The changes constituting local disease, have no such definiteness, either in place, extent, or outline, as the changes constituting development. Though certain morbid growths are more common in some parts of the body than in others (as warts on the hands, cancer in the breasts, tubercle in the lungs), yet they are not confined to these parts; nor, where found, are they anything like so precise in their relative positions as are the normal parts around. Their sizes are very variable: they bear no such constant proportions to the body as organs do. Their forms, too, are far less specific than organic forms. And they are extremely confused in their internal structures. That is, they are in all respects comparatively indefinite. The like peculiarity may be traced in decomposition. That total indefiniteness to which a dead body is finally reduced, is a state towards which the putrefactive changes tend from their commencement. The advancing destruction of the organic compounds blurs the tissue-structures — diminishes their distinctness. From the portions that have undergone most decay, there is a gradual transition to the less decayed portions, not a sharp demarcation. And step by step the lines of organization, once so precise, disappear. Similarly with social changes of an abnormal kind. The disaffection initiating a political outbreak, implies a loosening of those ties by which citizens are bound up into distinct classes and sub-classes. Agitation, growing into revolutionary meetings, fuses ranks that are usually separated. Acts of insubordination break through the ordained limits to individual conduct, and tend to obliterate the lines between those in authority and those beneath them. At the same time arrest of trade causes artizans and others to lose their occupations; and, ceasing to be functionally distinguished, they merge into an indefinite mass. When at last there comes positive insurrection, all magisterial and official powers, all class distinctions, all industrial differences, cease: organized society lapses into an unorganized aggregate of social units. Similarly, in so far as famines and pestilences cause changes from order towards disorder, they cause changes from definite arrangements to indefinite arrangements.

Thus, then, is that increase of heterogeneity which is not a trait of Evolution, distinguished from that increase of heterogeneity which is. Though in disease and after death, individual or social, the earliest modifications are additions to the pre-existing heterogeneity, they. are not additions to the pre-existing definiteness. From the outset they begin to destroy this definiteness, and gradually produce a heterogeneity that is indeterminate instead of determinate. As a city, already multiform in its variously-arranged structures of various architecture, may be made more multiform by an earthquake, which leaves part of it standing and overthrows other parts in different ways and degrees, but is at the same time reduced from orderly arrangement to disorderly arrangement; so may organized bodies be made for a time more multiform by changes which are nevertheless disorganizing changes. And in the one case as in the other, it is the absence of definiteness which distinguishes the multiformity of regression from the multiformity of progression.

If advance from the indefinite to the definite is an essential characteristic of Evolution, we shall of course find it everywhere displayed; as in the last chapter we found displayed the advance from the homogeneous to the heterogeneous. To see whether it is so, let us now consider the same several classes of facts.

§130. Beginning, as before, with a hypothetical illustration, we have to note that each step in the evolution of the Solar System, supposing it to have originated from diffused matter, was an advance towards more definite structure. As usually conceived, the initial nebula was irregular in shape and with indistinct margins, like those of nebulae now existing. Having partially-different proper motions, the parts of its attenuated substance, while being drawn together, generated, by the averaging of their motions, as well as by changes in the directions of these motions, a certain angular momentum; and the entire mass as it concentrated and acquired rotation must have assumed the form of an oblate spheroid which with every increase of density, became more specific in outline, and had its surface more distinctly marked off from the surrounding void. Simultaneously, the constituent portions of nebulous matter, instead of moving round their common centre of gravity in various planes, as they would at first do, must have had these planes more and more merged into a single plane, that became less vague as the concentration progressed — became gradually defined.

According to the hypothesis, change from indistinct characters to distinct ones, was repeated in the evolution of planets and satellites. A gaseous spheroid is less definitely limited than a liquid spheroid, since it is subject to larger undulations of surface, and to greater distortions of general form; and, similarly, a liquid spheroid, covered as it must be with waves of various magnitudes, tidal and other, is less definite than a solid spheroid. The decrease of oblateness which goes along with increase of integration, brings relative definiteness of other elements. A concentrating planet having an axis inclined to the plane of its orbit, must, while very oblate, have its plane of rotation much disturbed by external attractions; whereas its approach to a spherical form, involves a smaller precessional motion, and less marked variations in the direction of its axis.

With progressing settlement of the space-relations, the force-relations simultaneously become more settled; and the exact calculations of physical astronomy show us how definite these force-relations now are. In short, it needs but to think of the contrast between the chaos of the primitive nebula and the ordered relations of the Solar System in the sizes, shapes, motions, and combined inter-actions of its members, to see that increase of definiteness has been a marked trait of its evolution.

§131. From that primitive molten state of the Earth inferable from geological data as well as from the nebular hypothesis (probably a liquid shell having a nucleus of gases above the "critical point" of temperature, kept by pressure at a density as great as that of the superjacent liquid) the transition to its existing state has been through stages in which the characters became more determinate. A liquid spheroid is less specific than a solid spheroid in having no fixed distribution of parts. Currents of molten matter, though kept to certain general circuits by the conditions of equilibrium, cannot, in the absence of solid boundaries, be precise in their limits and directions: all parts must be in motion with respect to other parts. But a superficial solidification, even though partial, is a step towards the establishment of definite relations of position. In a thin crust, however, often ruptured by disturbing forces, and moved by every tidal undulation, fixity of relative position can be but temporary. Only as the crust thickens can there arise distinct and settled geographical positions. Observe, too, that when, on a surface adequately cooled, there begins to precipitate the water floating above as vapour, the deposits cannot maintain definiteness either of state or place. Falling on a solid envelope not thick enough to preserve anything beyond slight variations of level, the water must form small and shallow pools over the coolest areas; which areas must pass insensibly into others that are too hot to allow condensation. With progressing refrigeration, however — with a thickening crust, a consequent formation of larger elevations and depressions, and the precipitation of more atmospheric water, there comes an arrangement of parts which is comparatively fixed; and the definiteness of position increases, until there result continents and oceans — a distribution that is not only topographically settled, but presents separations of land from water more definite than could have existed when all the uncovered areas were low islands with shelving beaches, over which the tide ebbed and flowed to great distances.

Respecting the characters classed as geological, we may draw kindred inferences. While the Earth's crust was thin, mountain-chains were impossibilities: there could not have been long and well-defined axes of elevation, with distinct water-sheds and areas of drainage. Moreover, the denudation of small islands by small rivers, and by tidal streams both feeble and narrow, would produce no clearly-marked sedimentary strata. Confused and varying masses of detritus, such as we now find at the mouths of brooks, must have been the prevailing formations. And these could give place to distinct strata, only as there arose continents and oceans, with their great rivers, long coast-lines, and wide-spreading marine currents.

There must simultaneously have resulted more definite meteorological conditions. Differences of climates and seasons grew relatively decided as the heat derived from the Sun became distinguishable from the proper heat of the Earth; and the production of more specific conditions in each locality was aided by increasing permanence in the distribution of lands and seas. These are conclusions sufficiently obvious.

§132. We come now to the evidence yielded by organic bodies. In place of deductive illustrations, we shall here find illustrations which have been inductively established, and are therefore less open to criticism. The course of mammalian development, for example, will supply us with numerous proofs ready-described by embryologists.

The first change which the ovum of a mammal undergoes after repeated segmentation has reduced it to a mulberry-like mass, is the appearance of a distinction between the peripheral or epiblastic cells of this mass and the internal or hypoblastic cells. While growing rapidly the cluster of cells becomes hollow, and the blastodermic vesicle so formed presents a definite contrast between the outer layer, or epiblast, and its contents. The mass of hypoblast cells, having at first an indefinite, lens-like figure attached to the inside of the epiblast, spreads out and flattens into a membrane, the boundary of which is irregular — indefinite alike in form and constitution. And then the middle or thicker part presently becomes an opaque circular spot constituting the embryonic area: a spot which gradually acquires a pronounced outline. In the centre of this there at length comes the primitive streak or trace, which, as its name implies, is indefinite but by-and-by "becomes a more pronounced structure." Within this streak or trace the vertebrate axis first shows itself. Beginning as a shallow groove, it becomes slowly more pronounced; its sides grow higher; their summits overlap and at last unite; and so the indefinite groove passes into a definite tube, forming the vertebral canal. In this vertebral canal the leading divisions of the brain are at first discernible only as slight bulgings; while the proto-vertebrae commence as indistinct modifications of the tissue bounding the canal. Meanwhile in kindred ways the indefinite out-spread membrane through which are absorbed the materials for the unfolding structures around, is changed, into a definite alimentary canal. And in an analogous manner the entire embryo, which at first lies outspread on the yelk-sack, gradually rises up from it, and by the infolding of its ventral region becomes a separate mass, definitely outlined, connected with the yelk-sack only by a narrow duct.

These changes through which the general structure is marked out with slowly-increasing precision, are paralleled in the evolution of each organ. The liver commences by multiplication of certain cells in the wall of the intestine. The thickening produced by this multiplication, "increases so as to form a projection upon the exterior of the canal — a hollow bud;" and at the same time that the organ grows and becomes distinct from the intestine, the channels running through it are transformed into ducts having clearly-marked walls. Similarly, certain cells of the external coat of the alimentary canal at its upper portion, accumulate into lumps or buds from which the lungs are developed; and these, in their general outlines and detailed structure, acquire distinctness step by step. But even were no examples given, it would be undeniable that since a simple cluster of similar cells grows into head, trunk, and limbs of distinct shapes, each made up of many organs containing parts severally having clear outlines and composed of specific tissues, increase of definiteness has been a leading trait of the transformation.

Changes of this order continue long after birth; and, in the human being, are some of them not completed till middle life. During youth, most of the articular surfaces of the bones remain rough and fissured — the calcareous deposit ending irregularly in the surrounding cartilage. But between puberty and the age of thirty, these articular surfaces are finished off into smooth, hard, sharply-cut "epiphyses." Generally, indeed, we may say that increase of definiteness continues when there has ceased to be any appreciable increase of heterogeneity. And there is reason to think that those modifications which take place after maturity bringing about old age and death, are modifications of this nature; since they cause rigidity of structure, a consequent restriction of movement and of functional pliability, a gradual narrowing of the limits within which the vital processes go on, ending in an organic adjustment too precise — too narrow in its margin of possible variation to permit the requisite adaptation to changes of external conditions.

§133. To give clear proof that the Earth's Flora and Fauna, regarded either as wholes or in their separate species, have progressed in definiteness, is no more possible than it was to prove that they have progressed in heterogeneity: the facts are not sufficient. If, however, we allow ourselves to reason from the hypothesis, now daily rendered more probable, that every species has arisen through the accumulation of modifications upon modifications, just as every individual arises. we shall see that there must have been a progress, from the indeterminate to the determinate, both in the particular forms and in the groups of forms.

We may set out with the significant fact that the lowest organisms (which are analogous in structure to the germs of all higher ones) have so little definiteness that it is difficult, if not impossible, to decide whether they are plants or animals. Respecting sundry of them there are unsettled disputes between zoologists and botanists. Note next that among the Protozoa, great indefiniteness of shape is general. Of sundry shell-less Rhizopods the form is so irregular as to admit of no description: it is neither alike in any two individuals nor in the same individual at successive moments. By aggregation of Protozoa, are produced, among other creatures, the Sponges, most of which are indefinite in size, in contour, in internal arrangement; and such more definite aggregates as the Hydra are made indefinite both by the great differences between their contracted and expanded states and by their reproductive developments. As further showing how relatively indeterminate are the simplest organisms, it may be mentioned that their structures vary greatly with surrounding conditions: so much so that, among the Protozoa and Protophyta, many forms which were once classed as distinct species, and even as distinct genera, are found to be merely varieties of one species. If, now, we call to mind how precise in their traits are the highest organisms — how sharply cut their outlines, how invariable their proportions, and how comparatively constant their structures under changed conditions; we cannot deny that greater definiteness is one of their characteristics. If they have been evolved out of lower organisms, increase of definiteness has been an accompaniment of their evolution.

That, in course of time, species have become more sharply marked off from other species, genera from genera, and orders from orders, is a conclusion not admitting of a more positive establishment than the foregoing. If, however, species and genera and orders have arisen by evolution, then, as Mr. Darwin shows, the contrasts between groups must have become greater. Disappearance of intermediate forms, less fitted for special spheres of existence than the extreme forms they connected, must have made the differences between the extreme forms decided; and so, from indistinct varieties, must have been produced distinct species: an inference which is in harmony with what we know respecting races of men and races of domestic animals.

§134. The successive phases through which societies pass, obviously display the progress from indeterminate arrangements to determinate arrangements. A wandering tribe of savages, being fixed neither in its locality nor in its internal distribution, is far less definite in the relative positions of its parts than a nation. In such a tribe the social relations are confused and unsettled. Political authority is vague. Distinctions of rank are neither clearly marked nor impassable. And save in the different occupations of men and women, there are no decided industrial divisions. Only in tribes of considerable size, which have enslaved other tribes, is economic differentiation distinct.

But one of these primitive societies that evolves, becomes step by step more specific. Increasing in size, consequently ceasing to be so nomadic, and restricted in its range by neighbouring societies, it acquires, after prolonged border warfare, a settled territorial boundary. The distinction between the ruling race and the people, sometimes amounts, in the popular belief, to a difference of nature. The warrior-class attains a perfect separation from classes devoted to the cultivation of the soil or to other occupations regarded as servile. And there arises a priesthood which is defined in its rank, its functions, its privileges. This sharpness of definition, growing both greater and more variously exemplified as societies advance to maturity, is extremest in those which have reached their full development or are declining. Of ancient Egypt we read that its social divisions were precise and its customs rigid. Recent investigations make it more than ever clear that among the Assyrians and surrounding peoples, not only were the laws unalterable, but even the minor habits, down to those of domestic routine, Assessed a sacredness which insured their permanence. In India at the present day, the unchangeable distinctions of caste, not less than the constancy in modes of dress, industrial processes, and religious observances, show how definite are the arrangements where the antiquity is great. Nor does China, with its long-settled political organization, its elaborate and precise conventions, fail to exemplify the same truth.

The successive phases of our own and adjacent societies, furnish facts somewhat different in kind but similar in meaning. Originally monarchical authority was more baronial, and baronial authority more monarchical, than afterwards. Between modern priests and the priests of old times, who while officially teachers of religion were also warriors, judges, architects, there is a marked difference in definiteness of function. And among the people engaged in productive occupations, like contrasts hold: the regulative parts have become definitely distinct from the operative parts and the distributive parts from both. The history of our constitution, reminding us how the powers of King, Lords, and Commons have been gradually settled, describes analogous changes. Countless facts bearing the like construction meet us when we trace the development of legislation; in the successive stages of which we find statutes gradually rendered more specific in their applications to particular cases. Even now each new law beginning as a vague proposition, is, in the course of enactment, elaborated into specific clauses; and only after its interpretation has been established by judges' decisions in courts of justice, does it reach its final definiteness. From the annals of minor institutions like evidence may be gathered. Religious, charitable, literary, and all other societies, starting with ends and methods roughly sketched out and easily modifiable, show us how, by the accumulation of rules and precedents, the purposes become more precisely formulated and the modes of action more restricted; until at last decay follows a fixity which admits of no adaptation to new conditions. Should it be objected that among civilized nations there are examples of decreasing definiteness (instance the breaking down of limits between ranks), the reply is, that such apparent exceptions are the accompaniments of a social metamorphosis — a change from the military type of social structure to the industrial type, during which old lines of structure are disappearing and new ones becoming more marked.

§135. All organized results of social action — all super-organic structures, pass through parallel phases. Being, as they are, objective products of subjective processes, they must display corresponding changes; and that they do this, the cases of Language, of Science, of Art, clearly prove.

Strike out from our sentences everything but nouns and verbs, and there stands displayed the vagueness characterizing undeveloped tongues. Each inflection of a verb, or addition by which the case of a noun is marked, by limiting the conditions of action or of existence, enables men to express their thoughts more precisely. That the application of an adjective to a noun, or an adverb to a verb narrows the class of things or changes indicated, implies that the additional word serves to make the proposition more distinct. And similarly with other parts of speech.

The like effect results from the multiplication of words of each order. When the names for objects, and acts, and qualities, are but few, the range of each is proportionately wide, and its meaning therefore unspecific. The similes and metaphors so much used by aboriginal races, indirectly and imperfectly suggest ideas which they cannot express directly and perfectly from lack of words. Or to take a case from ordinary life, if we compare the speech of the peasant who, out of his limited vocabulary, can describe the contents of the bottle he carries, only as "doctor's stuff" which he has got for his "sick" wife, with the speech of the physician, who tells those educated like himself the particular composition of the medicine and the particular disorder for which he has prescribed it; we have vividly brought home to us the precision which language gains by the multiplication of terms.

Again, in the course of its evolution, each tongue acquires a further accuracy through processes which fix the meaning of each word. Intellectual intercourse slowly diminishes laxity of expression. By-and-by dictionaries give definitions. And eventually, among the most cultivated, indefiniteness is not tolerated, either in the terms used or in their grammatical combinations.

Once more, languages considered as wholes become more sharply marked off from one another, and from their common parent; as witness, in early times, the clear distinction that arose between the two connate languages Greek and Latin, and in later times the divergence of three Latin dialects into Italian, French, and Spanish.

§136. In his History of the Inductive Sciences, Dr. Whewell says that the Greeks failed in physical philosophy because their "ideas were not distinct, and appropriate to the facts." I do not quote this remark for its luminousness; since it would be equally proper to ascribe the indistinctness and inappropriateness of their ideas to the imperfection of their physical philosophy; but I quote it because it serves as good evidence of the indefiniteness of primitive science. The same work and its fellow, The Philosophy of the Inductive Sciences, yield other evidences equally good, because equally independent of any such hypothesis as is here to be established. Respecting mathematics, we have the fact that geometrical theorems grew out of empirical methods; and that these theorems, at first isolated, did not acquire the clearness which demonstration gives, until they were arranged by Euclid into a series of dependent propositions. At a later period, the same general truth was exemplified in the progress from the "method of exhaustions" and the "method of indivisibles" to the "method of limits;" which is the central idea of the infinitesimal calculus. in early mechanics may be traced a dim perception that action and reaction are equal and opposite; though, for ages after, this truth remained unformulated. And similarly, the property of inertia, though not distinctly comprehended until Kepler lived, was vaguely recognized long before. "The conception of statical force," "was never presented in a distinct form till the works of Archimedes appeared;" and "the conception of accelerating force was confused, in the mind of Kepler and his contemporaries, and did not become clear enough for purposes of sound scientific reasoning before the succeeding century." To which specific assertions may be added the general remark, that "terms which originally, and before the laws of motion were fully known, were used in a very vague and fluctuating sense, were afterwards limited and rendered precise." When we turn from abstract scientific conceptions to the concrete previsions of science, of which astronomy furnishes numerous examples, a like contrast is visible. The times at which celestial phenomena will occur, have been predicted with ever-increasing accuracy. Errors once amounting to days are now diminished to seconds. The correspondence between the real and supposed forms of orbits has been gradually rendered more precise. Originally thought circular, then epicyclical, then elliptical, orbits are now ascertained to be curves which always deviate from perfect ellipses, and are ever undergoing changes.

But the general advance of Science in definiteness is best shown by the contrast between its qualitative stage and its quantitative stage. At first the facts ascertained were that between such and such phenomena some connexion existed — that the appearances a and b always occurred together or in succession; but it was known neither what was the nature of the relation between a and b, nor how much of a accompanied so much of b. The development of Science has in part been the reduction of these vague connexions to distinct ones. Most relations have been classed as mechanical, chemical, thermal, electric, magnetic, etc.; and we have learnt to infer the relative amounts of the antecedents and consequents with exactness. Of illustrations, some furnished by physics have been given, and from other sciences plenty may be added. We have ascertained the constituents of numerous compounds which our ancestors could not analyze, and of a far greater number which they never even saw; and the combining equivalents of the elements are now accurately calculated. Physiology shows advance from qualitative to quantitative prevision in ascertaining definite relations between organic products and the materials consumed; as well as in measurement of functions by spirometer and sphygmograph. By Pathology it is displayed in the use of the statistical method of determining the sources of diseases, and the effects of treatment. In Botany and Zoology, the numerical comparisons of Floras and Faunas, leading to specific conclusions respecting their sources and distributions, illustrate it. And in Sociology, questionable as are many conclusions drawn from the classified sum-totals of the census, from the Board-of-Trade tables, and from criminal returns, it must be admitted that these imply a progress towards more precise conceptions of social phenomena.

That an essential characteristic of advancing Science is increase in definiteness, appears indeed almost a truism, when we remember that Science may be described as definite knowledge, in contradistinction to that indefinite knowledge possessed by the uncultured. And if, as we cannot question, Science has, in the course of ages, been evolved out of this indefinite knowledge of the uncultured, then, the gradual acquirement of that great definiteness which now distinguishes it, must have been a leading trait in its evolution.

§137. The arts, industrial and aesthetic, supply illustrations perhaps still more striking. Palaeolithic flint implements show the extreme want of precision in men's first handiworks. Though a great advance on these is seen in the tools and weapons of existing savage tribes, yet an inexactness in forms and fittings distinguishes such tools and weapons from those of civilized races. In a smaller degree, the productions of the less-advanced nations are characterized by like defects. A Chinese junk, with all its contained furniture and appliances, nowhere presents a line that is quite straight, a uniform curve, or a true surface. Nor do the utensils and machines of our ancestors fail to exhibit a similar inferiority to our own. An antique chair, an old fireplace, a lock of the last century, or almost any article of household use that has been preserved for a few generations, proves by contrast how greatly the industrial products of our time excel those of the Past in their accuracy. Since planing machines have been invented, it has become possible to produce absolutely straight lines, and surfaces so truly level as to be air-tight when applied to each other. While in the dividing-engine of Troughton, in the micrometer of Whitworth, in microscopes that show fifty thousand divisions to the inch, and in ruled divisions up to 200,000, we have an exactness as far exceeding that reached in the works of our great-grandfathers, as theirs exceeded that of the aboriginal celt-makers.

In the Fine Arts there has been a parallel progress. From the rudely-carved and painted idols of savages, through the early sculptures characterized by limbs without muscular detail, wooden-looking drapery, and faces devoid of individuality, up to the later statues of the Greeks or some of those now produced, the increased accuracy of representation is conspicuous. Compare the mural paintings of the Egyptians with the paintings of medieval Europe, or these with modern paintings, and the more precise rendering of the appearances of objects is manifest. It is the same with fiction and the drama. In the marvellous tales current among Eastern nations, in the romantic legends of feudal Europe, as well as in the mystery-plays and those immediately succeeding them, we see great want of correspondence to the realities of life; alike in the predominance of supernatural events, in the extremely improbable occurrences, and in the vaguely-indicated personages. Along with social advance, there has been a progressive diminution of unnaturalness — an approach to truth of representation. And now, cultivated men applaud novels and plays in proportion to the fidelity with which they exhibit characters. improbabilities, like the impossibilities which preceded them, are disallowed; and we see fewer of those elaborate plots which life rarely furnishes: realities are more definitely pictured.

§138. Space might be filled with evidences of other kinds, but the basis of induction is already wide enough. Proof that all Evolution is from the indefinite to the definite, we find not less abundant than proof that all Evolution is from the homogeneous to the heterogeneous.

It should, however, be added that this advance in definiteness is not a primary but a secondary phenomenon — is a result incidental on other changes. The transformation of a whole that was originally diffused and uniform into a concentrated combination of multiform parts, implies progressive separation both of the whole from its environment and of the parts from one another. While this is going on there must be indistinctness. Only as the whole gains density, does it become sharply marked off from the space or matter lying outside of it; and only as each division draws into its mass those peripheral portions which are at first imperfectly disunited from the peripheral portions of neighbouring divisions, can it acquire anything like a precise outline. That is to say, the increasing definiteness is a concomitant of the increasing consolidation, general and local. While the secondary re-distributions are ever adding to the heterogeneity, the primary redistribution, while augmenting the integration, is incidentally giving distinctness to the increasingly unlike parts as well as to the aggregate of them.

But though this universal trait of Evolution is a necessary accompaniment of the traits set forth in preceding chapters, it is not expressed in the words used to describe them. It is therefore needful further to modify our formula. The more specific idea of Evolution now reached is — a change from an indefinite, incoherent homogeneity, to a definite coherent heterogeneity, accompanying the dissipation of motion and integration of matter.

Chapter 17

The Law of Evolution (concluded)

§139. The conception of Evolution elaborated in the foregoing chapters, is still incomplete. True though it is, it is not the whole truth. The transformations which all things undergo during the ascending phases of their existence, we have contemplated under three aspects; and by uniting these three aspects as simultaneously presented, we have formed an approximate idea of the transformations. But there are concomitant changes about which nothing has yet been said, and which, though less conspicuous, are no less essential.

For thus far we have attended only to the re-distribution of Matter, neglecting the accompanying redistribution of Motion. Distinct or tacit reference has, indeed, repeatedly been made to the dissipation of Motion, that goes on along with the concentration of Matter; and were all Evolution absolutely simple, the total fact would be contained in the proposition that as Motion dissipates Matter concentrates. But while we have recognized the ultimate re-distribution of the Motion, we have passed over its proximate re-distribution. Though something has from time to time been said about the escaping motion, nothing has been said about the motion which does not escape. In proportion as Evolution becomes compound — in proportion as an aggregate retains, for a considerable time, such quantity of motion as permits secondary re-distributions of its component matter, there necessarily arise secondary redistributions of its retained motion. As fast as the parts are transformed, there goes on a transformation of the sensible or insensible motions possessed by the parts. They cannot become more integrated, either individually or as a combination, without their motions, individual or combined, becoming more integrated. There cannot arise among them heterogeneities of size, of form, of quality, without there also arising heterogeneities in the amounts and directions of their motions, or the motions of their molecules. And increasing definiteness of the parts implies increasing definiteness of their motions. In short, the rhythmical actions going on in each aggregate, must differentiate and integrate at the same time that the structures do so.

§139a. The general theory of this re-distribution of the retained motion, must here be briefly stated. Properly to supplement our conception of Evolution under its material aspect by a conception of Evolution under its dynamical aspect, we have to recognize the source of the integrated motions that arise, and to see how their increased multiformity and definiteness are necessitated.

If Evolution is passage from a diffused state to an aggregated state, then the motions of the celestial bodies must have resulted from the uncancelled motions of their once dispersed components. Along with the molecular motions everywhere active, there were molar motions of those vast streams of nebulous matter which were generated during the process of concentration — molar motions of which large portions were gradually dissipated as heat, leaving undissipated portions. But since the molar motions of these nebulous streams were constituted from the motions of multitudinous incoherent gaseous parts severally moving more or less independently it follows that when aggregation into a liquid and finally solid celestial mass was reached, these partially independent motions of the incoherent parts became merged into the motion of the whole: or, in other words, unintegrated motions became an integrated motion.

While we must leave in the shape of hypothesis the belief that the celestial motions have thus originated, we may see, as a matter of fact, that the integration of insensible motions originates all sensible motions on the Earth's surface. As all know, the denudation of lands and deposit of new strata, are effected by water while descending to the sea, or during the arrest of those undullations produced on it by winds; and, as before said, the elevation of water to the height whence it fell, is due to solar heat, as is also the genesis of those aerial currents which drift it about when evaporated and agitate its surface when condensed. That is to say, the molecular motion of the ethereal medium is transformed into the motion of gases, thence into the motion of liquids, and thence into the motion of solids: stages in each of which a certain amount of molecular motion is lost and an equivalent motion of masses gained. It is the same with organic movements. Certain rays issuing from the Sun, enable the plant to reduce special elements existing in gaseous combinations around it, to solid forms — enable the plant, that is, to grow and carry on its functional changes. And since growth, equally with circulation of sap, is a mode of sensible motion, while those rays which have been expended in generating both consist of insensible motions, we have here, too a transformation of the kind alleged Animals, derived as their forces are, directly or indirectly, from plants, carry this transformation a step further. The automatic movements of the viscera, together with the voluntary movements of the limbs and body at large, arise at the expense of certain molecular movements throughout the nervous and muscular tissues; and these originally arose at the expense of certain other molecular movements propagated by the Sun to the Earth; so that both the structural and functional motions which organic Evolution displays, are motions of aggregates generated by the arrested motions of units. Even with the aggregates of these aggregates the same rule holds. For among associated men the progress is ever towards a merging of individual actions in the actions of corporate bodies. In militant life this is seen in the advance from the independent fighting of separate warriors to the combined fighting of regiments, and in industrial life in the advance from the activities of separate workers to the combined activities of factory hands. So is it, too, when instead of acting alone citizens act in bodies — companies, unions, associations, etc. While, then, during Evolution the escaping motion becomes, by widening dispersion, more disintegrated, the motion that is for a time retained, becomes more integrated; and so, considered dynamically, Evolution is a decrease in the relative movements of parts and an increase in the relative movements of wholes — using the words parts and wholes in their most general senses. The advance is from the motions of simple molecules to the motions of compound molecules; from molecular motions to the motions of masses; and from the motions of smaller masses to the motions of larger masses.

The accompanying change towards greater multiformity among the retained motions, takes place under the form of an increased variety of rhythms. A multiplication of rhythms must accompany a multiplication in the degrees and modes of aggregation, and in the relations of the aggregated masses to incident forces. The degree or mode of aggregation will not, indeed, affect the rate or extent of rhythm where the incident force increases as the aggregate increases, which is the case with gravitation: here the only cause of variation in rhythm is difference of relation to the incident force; as we see in a pendulum which, though unaffected in its movements by a change in the weight of the bob, alters its rate of oscillation when its length is altered or when, otherwise unchanged, it is taken to the equator. But in all cases where the incident forces do not vary as the masses, every new order of aggregation initiates a new order of rhythm: witness the conclusion drawn from the recent researches into radiant heat and light, that the molecules of different gases have different rates of undulation.* So that increased multiformity in the arrangement of matter necessarily generates increased multiformity of rhythm; both through increased variety in the sizes and forms of aggregates, and through increased variety in their relations to the forces which move them. That these motions, as they become more integrated and more heterogeneous, must become more definite, is a proposition that need not detain us. In proportion as any part of an evolving whole segregates and consolidates, and in so doing loses the relative mobility of its components, its aggregate motion must obviously acquire distinctness.

<* This was written in 1867.>

Here, then, to complete our conception of Evolution, we must contemplate throughout the Cosmos, these metamorphoses of retained motion which accompany the metamorphoses of component matter. We may do this with comparative brevity: the reader having now become so familiar with the mode of looking at the facts, that less illustration will suffice. To save space, it will be convenient to deal with the several aspects of the metamorphoses at the same time.

§140. Masses of diffused matter moving towards a common centre, from many points at many distances with many degrees of indirectness, must carry into the nebulous mass eventually formed, numerous momenta unlike in their amounts and directions. As the integration progresses, such parts of these momenta as conflict are mutually neutralized, and dissipated as heat. Unless the original distribution is quite symmetrical, which is infinitely improbable, rotation will result. The mass having at first unlike angular velocities at the periphery and at various distances from the centre will have its differences of angular velocity gradually reduced; advancing towards a final state, now nearly reached by the Sun in which the angular velocity of the whole mass is the same — in which the motion is integrated. So, too, with each planet and satellite. Progress from the motion of a nebulous ring, incoherent and admitting of much relative motion within its mass, to the motion of a dense spheroid, is progress to a motion that is completely integrated. The rotation, and the translation through space, severally become one and indivisible. Meanwhile, there has been established that further integration displayed by the motions of the Solar System as a whole. Locally in each planet and its satellites, and generally in the Sun and the planets, we have a system of simple and compound rhythms, with periodic and secular variations, forming together an integrated set of movements.

Along with advancing integration of the motions there has gone advance in the multiformity and distinctness of them. The matter which, in its original diffused state, had movements that were confused, indeterminate, or without sharply-marked distinctions, has, during the evolution of the Solar System, acquired definitely heterogeneous movements. The periods of revolution of all the planets and satellites are unlike; as are also their times of rotation. Out of these definitely heterogeneous motions of a simple kind, arise others that are complex, but still definite; — as those produced by the revolutions of satellites compounded with the revolutions of their primaries; as those of which precession is the result; and as those which are known as perturbations. Each additional complexity of structure has caused additional complexity of movements; but still, a definite complexity, as is shown by having calculable results.

§141. While the Earth's surface was molten, the currents in the voluminous atmosphere surrounding it, mainly of ascending heated gases and of descending precipitated liquids, must have been local, numerous, indefinite, and but little distinguished from one another. But when after a vast period the surface, now solidified, had so far cooled that solar radiation began to cause appreciable differences of temperature between the equatorial and polar regions, an atmospheric circulation from poles to equator and from equator to poles, must have slowly established itself: other vast moving masses of air becoming, at last, trade-winds and other such permanent definite currents. These integrated motions, once comparatively homogeneous, were rendered heterogeneous as great islands and continents arose, to complicate them by periodic winds, caused by the varied heating of wide tracts of land at different seasons. Rhythmical motions of a constant and simple kind, were, by increasing multiformity of the Earth's surface, differentiated into an involved combination of constant and recurrent rhythmical motions, joined with smaller motions that are irregular.

Parallel changes must have taken place in the motions of water. On a thin crust, admitting of but small elevations and depressions, and therefore of but small lakes and seas, none beyond small local circulations were possible. But along with the formation of continents and oceans, came the vast movements of water from warm latitudes to cold and from cold to warm — movements increasing in amount, in definiteness, and in variety of distribution, as the features of the Earth's surface became larger and more contrasted. The like holds with drainage waters. The tricklings of insignificant streams over small tracts of land, were once alone possible; but as fast as wide areas came into existence, the motions of many tributaries became massed into the motions of great rivers; and instead of motions very much alike, there arose motions considerably varied.

Nor can we well doubt that the changes in the Earth's crust itself, have presented an analogous progress. Small, numerous, local, and like one another, while the crust was thin, the movements of elevation and subsidence must, as the crust thickened, have extended over larger areas, must have continued for longer eras in the same directions, and must have been made more unlike in different regions by local differences of structure.

§142. In organisms the advance towards a more integrated, heterogeneous, and definite distribution of the retained motion, which accompanies the advance towards a more integrated, heterogeneous, and definite distribution of the component matter, is mainly what we understand as the development of functions. All active functions are either sensible movements, as those produced by contractile organs; or such insensible movements as those propagated through nerves; or such insensible movements as those by which, in secreting organs, molecular re-arrangements are effected, and new combinations of matter produced. And during evolution functions, like structures, become more consolidated individually, as well as more combined with one another, at the same time that they become more multiform and more distinct.

The nutritive juices in animals of low types move hither and thither through the tissues quite irregularly, as local strains and pressures determine: in the absence of a true blood and a distinct vascular system, there is no definite circulation. But along with the structural evolution which establishes a good apparatus for distributing blood, there goes on the functional evolution which establishes large and rapid movements of blood, definite in their courses and definitely distinguished as efferent and afferent, and that are heterogeneous both in their directions and in their characters: being here divided into gushes and there continuous.

Again, accompanying the structural differentiations and integrations of the alimentary canal, there arise differentiations and integrations both of its mechanical movements and its actions of a non-mechanical kind. Along an alimentary canal of a primitive type there pass, almost uniformly from end to end, waves of constriction. But in a well-organized alimentary canal, the waves of constriction are widely unlike at different parts, in their kinds, strengths, and rapidities. In the oesophagus they are propulsive in their office, and travelling with considerable speed, take place at intervals during eating, and then do not take place till the next meal. In the stomach another modification of this originally uniform action occurs: the muscular constrictions are powerful, and continue during the long periods that the stomach contains food. Throughout the upper intestines, again, a further difference shows itself — the waves travel along without cessation but are relatively moderate. Finally, in the rectum this rhythm departs in another way from the common type: quiescence, lasting for many hours, is followed by a series of strong contractions. Meanwhile, the essential actions which these movements aid, have been growing more definitely heterogeneous. Secretion and absorption are no longer carried on in much the same way from end to end of the tube; but the general function divides into various subordinate functions. The solvents and ferments furnished by the coats of the canal and the appended glands, become widely unlike at upper, middle, and lower parts of the canal; implying different kinds of molecular changes. Here the process is mainly secretory there it is mainly absorbent, and in other places, as in the oesophagus, neither secretion nor absorption takes place to any appreciable extent. While these and other internal motions, sensible and insensible, are being rendered more various, and severally more integrated and more distinct, there is advancing the integration by which they are united into local groups of motions and a combined system of motions. While the function of alimentation subdivides, its subdivisions become co-ordinated, so that muscular and secretory actions go on in concert, and so that excitement of one part of the canal sets up excitement of the rest. Moreover, the whole alimentary function, while it supplies matter for the circulatory and respiratory functions, becomes so integrated with them that it cannot for a moment go on without them. And, as evolution advances, all three of these fundamental functions fall into greater subordination to the nervous functions — depend more and more on the due mount of nervous discharge; while at the same time their motions become co-ordinated, or in a sense integrated, with those of the nervo-muscular system, on which they depend for the supply of materials.

When we trace up the functions of motor organs the same truth discloses itself. Microscopic creatures are moved through the water by the oscillations of cilia, here large and single or double, and here smaller and numerous; and various larger forms, as the Turbellaria, progress by ciliary action over solid surfaces. These motions of cilia are, in the first place, severally very minute; in the second place they are homogeneous; and in the third place there is but little definiteness in them individually, or in their joint product, which is mostly a random change of position not directed to any selected point. Contrasting this ciliary action with the action of developed locomotive organs, we see that instead of many small or unintegrated movements there are a few comparatively large or integrated movements; that actions all alike are replaced by actions partially or wholly unlike; and that instead of being very feebly or almost accidentally co-ordinated, their definite co-ordination renders the motions of the body as a whole, precise. A parallel contrast, less extreme but sufficiently decided, is seen when we pass from the lower types of creatures with limbs to the higher types of creatures with limbs. The legs of a Centipede have motions that are numerous, small, and homogeneous; and are so little integrated that when the creature is divided and subdivided, the legs belonging to each part propel that part independently. But in one of the higher Arthropoda: as a Crab, the relatively few limbs have motions which are comparatively large in their amounts, which are considerably unlike one another, and which are integrated into total bodily movements of much definiteness.

§143. The last illustrations introduce us to illustrations of the kind classed as mental. They are the physiological aspects of the simpler among those functions which, under a more special and complex aspect, we distinguish as psychological. The phenomena subjectively known as changes in consciousness, are objectively known as nervous excitations and discharges, which science now interprets into modes of motion. Hence, in following up organic evolution, advance of the retained motion alike in integration, in heterogeneity, and in definiteness, may be expected to show itself both in the visible nervo-muscular actions and in the correlative mental changes. We may conveniently look at the facts as exhibited during individual evolution, before looking at them as exhibited in general evolution.

The progress of a child in speech very clearly displays the transformation. Infantine noises are comparatively homogeneous; alike as being severally long-drawn and nearly uniform from end to end, and as being constantly repeated with but little variation of quality. They are quite un-co-ordinated — there is no integration of them into compound sounds. They are inarticulate, or without those definite beginnings and endings and joinings characterizing words. Progress shows itself first in the multiplication of the inarticulate sounds: the extreme vowels are added to the medium vowels, and the compound to the simple. Presently the movements which form the simpler consonants are achieved, and some of the sounds become sharply cut; but this definiteness is partial, for only initial consonants being used, the sounds end vaguely. While an approach to distinctness thus results, there also results, by combination of different consonants with the same vowels, an increase of heterogeneity; and along with the complete distinctness which terminal consonants give, arises a further great addition to the number of unlike sounds produced. The more difficult consonants and the compound consonants, imperfectly articulated at first, are by-and-by articulated with precision; and hence arises another multitude of different and definite words — words that imply many kinds of vocal movements, severally performed with exactness, as well as perfectly integrated into complex groups. The subsequent advance to dissyllables and polysyllables, and to involved combinations of words, shows the still higher degree of integration and heterogeneity eventually reached by these organic motions.

The acts of consciousness correlated with these nervo-muscular acts, of course go through parallel phases; and the advance from childhood to maturity yields daily proof that the changes which, on their physical side are nervous processes, and on their mental side are processes of thought, become more various, more defined, more coherent. At first the intellectual functions are much alike in kind — recognitions and classifications of simple impressions alone go on; but in course of time these functions become multiform. Reasoning grows distinguishable, and eventually we have conscious induction and deduction; deliberate recollection and deliberate imagination are added to simple unguided association of ides; more special modes of mental action, as those which result in mathematics, music, poetry, arise; and within each of these divisions the mental movements are ever being further differentiated. In definiteness it is the same. At first the infant makes its observations so inaccurately that it fails to distinguish individuals. The child errs continually in its spelling, its grammar, its arithmetic. The youth forms incorrect judgments on the affairs of life. Only with maturity comes that precise co-ordination of data which is implied by a good adjustment of thoughts to things. Lastly, with the integration by which simple mental acts are combined into complex mental acts, we see the like. In the nursery you cannot obtain continuous attention — there is inability to form a coherent series of impressions; and there is a parallel inability to unite many co-existent impressions, even of the same order: witness the way in which a child's remarks on a picture, show that it attends only to the individual objects represented, and never to the picture as a whole. But advancing years bring the ability to understand an involved sentence, to follow long trains of reasoning, to hold in one mental grasp numerous concurrent circumstances. A like progressive integration takes place among the mental changes we distinguish as feelings; which in a child act singly, producing impulsiveness, but in an adult act more in concert, producing a comparatively balanced conduct.

After these illustrations supplied by individual evolution, we may deal briefly with those supplied by general evolution, which are analogous to them. A creature of very low intelligence, when aware of some large object in motion near it, makes a spasmodic movement, causing, it may be, a leap or a dart. The perceptions implied are relatively simple, homogeneous, and indefinite: the moving objects are not distinguished in their kinds as injurious or otherwise, as advancing or receding. The actions of escape, too, are all of one kind, have no adjustments of direction, and may bring the creature nearer the source of peril instead of further off. At a higher stage the dart or the leap is away from danger: the nervous changes are so far specialized that there results distinction of direction; indicating a greater variety among them, a greater co-ordination or integration of them in each process, and a greater definiteness. In still higher animals, able to discriminate between enemies and not-enemies, as a bird which flies from a man but not from a cow, the acts of perception have severally become united into more complex wholes, since cognition of certain differential attributes is implied; they have also become more multiform, since each additional component impression adds to the number of possible compounds; and they have, by consequence, become more specific in their correspondences with objects — more definite. And then in animals so intelligent that they identify by sight not species only but individuals of a species, the mental changes are yet further distinguished in the same three ways. In the course of human evolution the law is equally manifested. The thoughts of the savage are nothing like so heterogeneous in their kinds as those of the civilized man, whose complex environment presents a multiplicity of new phenomena. His mental acts, too are much less involved — he has no words for abstract ideas, and is found to be incapable of integrating the elements of such ideas. And in all but simple matters there is none of that precision in his thinking, and that grasping of many linked conceptions, which, among civilized men, leads to the exact conclusions of science.

§144. How in societies the movements or functions produced by the confluence of individual actions, increase in their amounts, their multiformities, their precision, and their combination, scarcely needs insisting upon after what has been potted out in foregoing chapters. For the sake of symmetry of statement, however, a typical example or two may be set down.

At first the military activities, undifferentiated from the rest (all men in primitive societies being warriors) are relatively homogeneous, ill-combined, and indefinite: savages making a joint attack severally fight independently; in similar ways, and without order. But as societies evolve the movements of the thousands of soldiers which replace the tens of warriors, are divided and re-divided in their kinds of movements: here are gunners, there infantry and elsewhere cavalry. Within each of the differentiated functions of these bodies there come others: there are distinct actions of privates, sergeants, captains, colonels, generals, as also of those who constitute the commissariat and those who attend to the wounded. The clustered motions that have thus become comparatively heterogeneous in general and in detail, have simultaneously increased in precision; so that in battle, men and the regiments formed of them, are made to take definite positions and perform definite acts at definite times. Once more, there has gone on that integration by which the multiform actions of an army are directed to a single end. By a co-ordinating apparatus having the commander-in-chief for its centre, the charges, and halts, and retreats are duly concerted; and a hundred thousand individual motions are united under one will.

Again on comparing the rule of a savage chief with that of a civilized government, aided by its subordinate local governments and their officers, down to the police, we see how, as men have advanced from tribes of hundreds to nations of millions, the regulative action has grown large in amount; how, guided by written laws, it has passed from vagueness and irregularity to comparative precision; and how it has subdivided into processes increasingly multiform. Or after observing how the barter that goes on among barbarians differs from our own commercial processes, by which a million's worth of commodities is distributed daily; by which the relative values of articles immensely varied in kinds and qualities are exactly measured, and the supplies adjusted to the demands; and by which industrial activities of all orders are so combined that each depends on the rest and aids the rest; we see that the kind of movement which constitutes trade, has become progressively more vast, more varied, more definite, and more integrated.

§145. A finished conception of Evolution thus includes the re-distribution of the retained motion, as well as that of the component matter. This added element of the conception is scarcely, if at all, less important than the other. The movements of the Solar System have a significance equal to that which the sizes, forms, and relative distances of its members possess. The Earth's geographical and geological structure are not more important elements in the order of Nature than are the motions, regular and irregular, of the water and the air clothing it. And of the phenomena presented by an organism, it must be admitted that the combined sensible and insensible actions we call its life, do not yield in interest to its structural traits. Leaving out, however, all implied reference to the way in which these two orders of facts concern us, it is clear that with each redistribution of matter there necessarily goes a re-distribution of motion; and that the unified knowledge constituting Philosophy, must comprehend both aspects of the transformation.

Our formula, therefore, needs an additional clause. To combine this satisfactorily with the clauses as they stand in the last chapter, is scarcely practicable; and for convenience of expression it will be best to change their order. On doing this, and making the requisite addition, the formula finally stands thus: — Evolution is an integration of matter and concomitant dissipation of motion; during which the matter passes from an indefinite, incoherent homogeneity to a definite, coherent heterogeneity and during which the retained motion undergoes a parallel transformation.

[Note. Only at the last moment, when this sheet is ready for press and all the rest of the volume is standing in type, so that new matter cannot be introduced without changing the "making up" throughout 150 pages, have I perceived that the above formula should be slightly modified. Hence my only practicable course is to indicate here the alteration to be made, and to set forth the reasons for it in Appendix A.

The definition of Evolution needs qualifying by introduction of the word "relatively" before each of its antithetical clauses. The statement should be that "the matter passes from a relatively indefinite, incoherent homogeneity to a relatively definite, coherent heterogeneity." Already this qualification has been indicated in a note to §116 (page 295), but, more effectually to exclude misapprehensions, it must be incorporated in the definition. In Appendix A are named the circumstances which led to inadequate recognition of it.]

Chapter 18

The Interpretation of Evolution

§146. Is this law ultimate or derivative? Must we rest satisfied with the conclusion that throughout all classes of concrete phenomena such is the course of transformation? Or is it possible for us to ascertain why such is the course of transformation? May we seek for some all-pervading principle which underlies this all-pervading process? Can the inductions set forth in the preceding four chapters be reduced to deductions?

Manifestly this community of result implies community of cause. It may be that of the cause no account can be given, further than that the Unknowable is manifested to us after this mode. Or, it may be that this mode of manifestation is implied by a simpler mode, from which these many complex effects follow. Analogy suggests the latter inference. Just as it was possible to interpret the empirical generalizations called Kepler's laws, as necessary consequences of the law of gravitation; so it may be possible to interpret the foregoing empirical generalizations as necessary consequences of some deeper law.

Unless we succeed in finding a rationale of this universal metamorphosis, we obviously fall short of that completely unified knowledge constituting Philosophy. As they at present stand, the several conclusions we have lately reached appear to be independent. There is no demonstrated connexion between increasing definiteness and increasing heterogeneity, or between both and increasing integration. Still less proof is there that these laws of the re-distribution of matter and motion, are necessarily correlated with those laws of the direction of motion and the rhythm of motion, previously set forth. But until we see these now separate truths to be implications of one truth, our knowledge remains imperfectly coherent.

§147. The task before us, then, is that of exhibiting the phenomena of Evolution in synthetic order. Setting out from an established ultimate principle, it has to be shown that the course of transformation among all kinds of existences, cannot but be that which we have seen it to be. It has to be shown that the re-distribution of matter and motion, must everywhere take place in those ways, and produce those traits, which celestial bodies, organisms, societies, alike display. And it has to be shown that in this universality of process, is traceable the same necessity which we find in each simplest movement around us, down to the accelerated fall of a stone or the recurrent beat of a harp-string.

In other words, the phenomena of Evolution have to be deduced from the Persistence of Force. As before said — "to this an ultimate analysis brings us down, and on this a rational synthesis must build up." This being the ultimate truth which transcends experience by underlying it, furnishes a common basis on which the widest generalizations stand; and hence these widest generalizations are to be unified by referring them to this common basis. Already the truths that there is equivalence among transformed forces, that motion follows the line of least resistance or greatest traction and that it is universally rhythmic, we have found to be severally deducible from the persistence of force; and this affiliation of them on the persistence of force has reduced them to a coherent whole. Here we have similarly to affiliate the universal traits of Evolution, by showing that, given the persistence of force, the re-distribution of Matter and Motion necessarily proceeds in such ways as to produce these traits. By doing this we shall unite them as correlative manifestations of one law, at the same time that we unite this law with the foregoing simpler laws.

§148. Before proceeding it will be well to set down some principles that must be borne in mind. In interpreting Evolution we shall have to consider, under their special forms, the various resolutions of force or energy which accompany the re-distributions of matter and motion. Let us glance at such resolutions under their most general forms.

Any incident force is primarily divisible into its effective and non-effective portions. In mechanical impact the entire momentum of a striking body is never communicated to the body struck: even under those most favourable conditions in which the striking body loses all its sensible motion, there still remains with it some of the original momentum under the shape of that insensible motion produced among its particles by the collision. Again, of the light or heat falling on any mass, a part, more or less considerable, is reflected; and only the remaining part works molecular changes in the mass. Next it is to be noted that the effective force is itself divisible into the temporarily effective and the permanently effective. The units of an aggregate acted on may undergo only those rhythmical changes of relative position which constitute increased vibration; or they may also undergo changes of relative position which are not from instant to instant neutralized by opposite ones. Of these the first, disappearing in the shape of radiating undulations, leave the molecular arrangement as it originally was; while the second conduce to one form of that re-arrangement characterizing compound Evolution. Yet a further distinction has to be made. The permanently effective force works out changes of relative position of two kinds — the insensible and the sensible. The insensible transpositions among the units are those constituting molecular changes, including what we call chemical composition and decomposition; and it is these which largely constitute the qualitative differences that arise in an aggregate. The sensible transpositions are such as result when certain of the units — molar units as well as molecular units — instead of being put into different relations with their immediate neighbours, are carried away from them and deposited elsewhere.

Concerning these divisions and subdivisions of any force affecting an aggregate, the fact which it chiefly concerts us to observe is, that they are complementary to one another. Of the whole incident force, the effective must be that which remains after deducting the non-effective. The two parts of the effective force must vary inversely as each other: where much of it is temporarily effective, little of it can be permanently effective; and vice versa. Lastly, the permanently effective force, being expended in working both the insensible re-arrangements which constitute molecular modification, and the sensible re-arrangements which result in structure, must generate of either kind an amount that is great or small in proportion as it has generated a small or great amount of the other.

Chapter 19

The Instability of the Homogenous Exemplifying Instability at Large*

<* The idea developed in this chapter originally formed part of an article on "Transcendental Physiology," published in 1857. See Essays, Vol. I.>

§149. The difficulty of dealing with transformations so many-sided as those which all existences have undergone, or are undergoing, is such as to make a definite or complete deductive interpretation seem almost hopeless. So to grasp the total process of re-distribution, as to see simultaneously its several necessary results in their actual interdependence, is scarcely possible. There is, however, a mode of rendering the process as a whole tolerably comprehensible. Though the genesis of the re-arrangement undergone by every evolving aggregate is in itself one, it presents to our intelligence several factors; and after interpreting the effects of each separately, we may, by synthesis of the interpretations, form an adequate conception.

The proposition which comes first in logical order, is, that some re-arrangement must result; and this proposition may be best dealt with under the more specific shape, that the condition of homogeneity is a condition of unstable equilibrium.

First, as to the meanings of the terms, respecting which some readers may need explanation. The state of "unstable equilibrium," so named in mechanics, is well illustrated by a stick standing on its lower end, in contrast with the state of stable equilibrium of a stick suspended by its upper end: the one instantly losing its equilibrium and the other regaining it if disturbed. But the reader must be warned against confusing the instability thus exemplified with the instability here to be treated of. The one shown by a stick on end may be called an external instability, while that which we have now to consider is an internal instability. It is not alleged that a homogeneous aggregate is liable because of its homogeneity to be overthrown or deranged by an external force. The allegation is that its component parts cannot maintain their arrangements unaltered: they must forthwith begin to change their relations to one another. Let us take a few illustrations.

Of mechanical ones the most familiar is that of the scales. If they be accurately made and not clogged by dirt or rust, it is impossible to keep a pair of scales perfectly balanced: eventually one scale will descend and the other ascend — they will assume a heterogeneous relation. Could a mass of water be brought into a state of perfect homogeneity — a state of complete quiescence, and exactly equal density throughout — yet the radiation of heat from neighbouring bodies, by affecting differently its different parts, would inevitably produce inequalities of density and consequent currents; and would so render it to that extent heterogeneous. Take a piece of red-hot matter, and however evenly heated it may at first be, it will quickly cease to be so: the exterior, cooling faster than the interior will become different from it in temperature. And the lapse into heterogeneity of temperature, so obvious. in this extreme case, takes place more or less in the cases of all surrounding objects, which are ever being warmed or cooled. The action of chemical forces supplies other illustrations. Expose a fragment of metal to air or water, and in course of time it will be coated with a film of oxide, carbonate, or other compound: its outer parts will become unlike its inner parts. Often the heterogeneity produced by the actions of chemical forces on the surfaces of masses, is not striking, because the changed portions are soon washed away, or otherwise removed. But if this be prevented comparatively complex structures result. In some quarries of trap-rock there are striking examples. Not unfrequently a piece of trap may be found reduced, by the action of the weather, to a number of loosely-adherent coats, like those of an onion. Where the block has been undisturbed, we may trace the whole series of these, from the angular, irregular outer one, through successively included ones in which the shape becomes gradually rounded, ending at length in a spherical nucleus. On comparing the original mass of stone with this group of concentric coats, each differing from the rest in form, and probably in the state of decomposition it has arrived at, we get a marked illustration of the multiformity to which, in lapse of time, a uniform body may be brought by external chemical action. The instability of the homogeneous is equally seen in the changes set up throughout the interior of a mass, when it consists of units that are not rigidly bound together. The molecules of a slowly-settling precipitate do not remain separate, and equably distributed through the fluid in which they make their appearance. They aggregate either into crystalline grains or into flocculi; and where the mass of fluid is great and the process prolonged, these flocculi do not continue equi-distant, but asSemble into groups. That is to say, there is a destruction of the balance at first subsisting among the diffused particles, and also of the balance at first subsisting among the groups into which these particles unite.

The instability thus variously illustrated is consequent on the fact that the several parts of any homogeneous aggregate are exposed to different forces — forces which differ either in kind or amount; and are of necessity differently modified. The relations of outside and inside, and of comparative nearness of the parts to neighbouring sources of influence, imply the reception of influences that are unlike in quantity or quality, or both: unlike changes, now temporary now permanent, being caused.

For like reasons the process must repeat itself in each of the component masses of units that are differentiated by the modifying forces. Each of these minor groups, like the major group, must gradually, in obedience to the unlike influences acting on it, lose its balance of parts, and pass from a uniform into a multiform state. And so on continuously. Whence, indeed, it follows that not only must the homogeneous lapse into non-homogeneous, but the more homogeneous must tend ever to become less homogeneous. If any given whole, instead of being absolutely uniform throughout, consist of parts distinguishable from one another — if each of these parts, while somewhat unlike other parts, is uniform within itself; then, each of them being in unstable equilibrium, it follows that while the changes set up within it must render it multiform, they must at the same time render the whole more multiform than before. The general principle, now to be followed out in its applications, is thus somewhat more comprehensive than the title of the chapter implies.

No demurrer to the conclusions drawn, can be based on the truth that perfect homogeneity nowhere exists; since, whether that state with which we commence be or be not one of perfect homogeneity, the process must equally be towards a relative heterogeneity.

§150. The stars are distributed with a threefold irregularity. There is first the marked contrast between the Milky Way and other parts of the heavens, in respect of the quantities of stars within given visual areas. There are secondary contrasts of like kind in the Milky Way itself, which has its thick and thin places; as well as throughout the celestial spaces in general, which are more closely strewn in some regions than in others. And there is a third order of contrasts produced by the aggregation of stars into small clusters. Besides this heterogeneity in the distribution of stars, considered without distinctions of kind, a further heterogeneity is disclosed when they are classified by their differences of colour, which answer to differences of physical constitution. While yellow stars are found in all parts of the heavens, red and blue stars are not so: there are wide regions in which both red and blue stars are rare; there are regions in which the blue occur in considerable numbers, and there are other regions in which the red are comparatively abundant. Yet one more irregularity of like significance is presented by the nebulae. These are not dispersed with anything like uniformity, but are far more numerous around the poles of the galactic circle than in the neighbourhood of its plane.

No one will expect that anything like a definite interpretation of this structure can be given on the hypothesis of Evolution, or any other hypothesis. Such an interpretation would imply some reasonable assumption respecting the pre-existing distribution of the stellar matter and of the matter forming nebulae, and we have no warrant for any assumption. If we allow imagination to range back through antecedent Possibilities and probabilities, we see it to be unlikely that homogeneous matter filled the space which our Sidereal System now fills, at a time immediately preceding its initiation. Rather the evidence which the heavens present implies that the distribution out of which the present distribution arose, was irregular in all respects. Though certain traits of our galaxy suggest that it has a vague individuality, and that, along with their special motions, its stars have some general motion; yet the evidence forces on us the conclusion that many varieties of changes have been simultaneously going on in its different parts. We find nebulae in all stages of concentration, star-clusters variously condensed, groups of larger stars approximating in different degrees, as well as regions like those which the nubeculae occupy, presenting complex structures and apparently active changes. The most which can be said respecting this total distribution is that, subject as all parts of our Sidereal System are to the law of gravitation, the heterogeneities it exhibits, everywhere implying a progressing concentration, that is, integration, point backward to a less heterogeneous state and point forward to a more heterogeneous state. But, leaving aside this too transcendent question, we may without undue rashness consider from the evolution point of view the changes to be anticipated in one of those collections of matter described as a diffused nebulosity, or one of those more distinct ones of which the outlying parts are compared to wisps of cloud blown about by the wind. The only evolutional process which can at first be displayed is the primary one of integration — the gathering together through mutual attraction of the parts; for in this early stage in which indefiniteness and incoherence are so fully exemplified, there does not yet exist such an aggregate as is capable of exhibiting secondary re-distributions: we have only the dispersed components of such an aggregate. Contemplating, then, only the process of integration, we may, without asking anything about the previous history of an irregular nebula, safely assume that its parts have their respective proper motions; for the chances are infinity to one against a state of rest relatively to one another. Further, the chances are infinity to one against their proper motions being such that during concentration they will cancel one another: the motion of some part, or the resultant of the motions of several parts, will constitute a proper motion distinct from that which mutual gravitation generates — a motion which, unless just counterbalanced by an opposite one (again an infinite improbability) will generate rotation. It may, indeed, be argued that, apart from any pre-existing proper motions of its parts, a nebulous mass, if irregular, will acquire rotation while integrating; since each outlying fragment, arriving after the rest have been gathered together, is infinitely unlikely to fall into the mass in such a manner that its motion will be entirely cancelled by resistance; but, falling into it so as to be deflected laterally, will have its motion of approach so changed in direction as to become in part a motion of revolution: a resultant of all such motions, largely conflicting, being an eventual rotation of the mass. It must not, however, be assumed that this will necessarily be the rotation of a solitary aggregate. The great nebula in Andromeda does not appear on the way to form a single body; and is an advanced spiral of which the that in Canes Venatici outer parts have a tangential motion too great to permit of their being drawn into the centre. Rather the apparent implication of the structure is that there will be formed a cluster of masses revolving round a common centre of gravity. Such cases, joined with those of the annular nebula, suggest that often the processes of integration result in compound structures, various in their kinds, while in other cases, and perhaps most frequently, single masses of rotating nebulous matter are formed.

Ignoring all such possibilities and probabilities, however, and limiting our attention to that form of the nebular hypothesis which regards the solar system as having resulted from a rotating spheroid of diffused substance; let us consider what consequence the instability of the homogeneous necessitates. Being oblate in figure, unlike in the densities of its centre and surface, unlike in their temperatures, and probably unlike in the angular velocities of its parts, such a mass cannot be called homogeneous; and any further changes exhibited by it can illustrate the general law, only as being changes from a more homogeneous to a less homogeneous state. Just noting that one of these changes is the increasing oblateness of form, let us go on to observe those which are to be found in the transformations of such of its parts as are at first homogeneous within themselves. If we accept the conclusion that the equatorial portion of this rotating and contracting spheroid will, at successive stages, have a centrifugal force great enough to prevent nearer approach to the centre of rotation, and will so be left behind; we shall find, in the fate of the detached ring, an exemplification of the principle we are following out. Consisting of gaseous matter such a ring, even if uniform at the time of its detachment, could not continue so. In the absence of equality among the forces, internal and external, acting on it, there must be a point or points at which the cohesion of its parts would be less than elsewhere — a point or points at which rupture would therefore take place. The original assumption was that the ring would rupture at one place only, and would then collapse on itself. But this was a more than questionable assumption: such, at least, I know to have been the opinion of the late Sir John Herschel. So vast a ring, consisting of matter having such feeble cohesion, must break up into many parts. Nevertheless, appeal to another high authority — the late Sir G. B. Airy — yielded verification for the belief that the ultimate result which Laplace predicted would take place. And here is furnished a further illustration of the instability of the homogeneous. For even supposing the masses of nebulous matter into which such a ring separated, were so much alike in their sizes and distances as to attract one another with exactly equal forces (which is infinitely improbable); yet the unequal actions of external disturbing forces would inevitably destroy their equilibrium — there would be one or more points at which adjacent masses would begin to part company. Separation, once commenced, would with accelerating speed lead to a grouping of the masses. A like result would eventually take place with the groups thus formed; until they at length aggregated into a single mass.

§151. Already so many references have been made to the formation of a crust over the originally incandescent Earth, that it may be thought superfluous again to name it. It has not, however, been thus far considered in connexion with the general principle under discussion. Here it must be noted as a nece ssary consequence of the instability of the homogeneous. In this cooling and soldification of the Earth's surface, we have one of the simplest, as well as one of the most important, instances of that change from a uniform to a multiform state which occurs in any mass through exposure of its component parts to unlike conditions. To the differentiation of the Earth's exterior from its interior, thus brought about, we must add one of the most conspicuous differentiations which the exterior itself afterwards undergoes, as being similarly brought about. Were the forces to which the surface of the Earth is subject, alike in all directions, there would be no reason why certain of its parts should become permanently unlike the rest. But being unequally exposed to the chief external centre of force — the Sun — its main divisions become unequally modified. While the crust thickens and cools, there arises that contrast, now so decided, between the polar and equatorial regions.

Along with these most marked physical differentiations of the Earth, there have been going on numerous chemical differentiations, admitting of similar interpretation. Leaving aside all speculations concerning the origin of the so-called simple substances, it will suffice to show how in place of that comparative homogeneity of the Earth's crust, chemically considered, which must have existed when its temperature was high, there has arisen, during its cooling, an increasing chemical heterogeneity. Let us contemplate this change somewhat in detail. At an extreme heat the bodies we call elements cannot combine. Even under such heat as can be generated artificially, some very strong affinities yield; and the great majority of chemical compounds are decomposed at much lower temperatures. Probably, therefore, when the Earth was in its first state of incandescence, there were no chemical combinations. But without drawing this inference, let us set out with the unquestionable fact that the compounds which can exist at the highest temperatures, and which must therefore have been the first formed as the Earth cooled, are those of the simplest constitutions. The protoxides (including under that head the alkalies, earths, etc.) are, as a class,the most stable compounds known — the least changeable by heat. These, consisting severally of one atom of each component element, are but one degree less homogeneous than the elements themselves. More heterogeneous than these, more decomposable by heat, and therefore later in the Earth's history, are the deutoxides, tritoxides, peroxides, etc.; in which two, three, four, or more atoms of oxygen are united with one atom of metal or other base. Still less able to resist heat are the salts, which present us with compound atoms each made up of five, six, seven, eight, ten, twelve, or more atoms, of three or more kinds. Then there are the hydrated salts of a yet greater heterogeneity, which undergo partial decomposition at much lower temperatures. After them come the further-complicated supersalts and double salts, having a stability again decreased; and so throughout. After making a few unimportant qualifications demanded by peculiar affinities, it may be asserted as a general law of these inorganic combinations that, other things equal, the stability decreases as the complexity increases. When we pass to the compounds which make up organic bodes, we find this general law further exemplified; we find much greater complexity and much less stability. A molecule of albumen, for instance, consists of more than two hundred ultimate units of five different kinds. According to the latest analyses it contains in each molecule, 72 of carbon, 18 of nitrogen, 1 of sulphur, 112 of hydrogen, and 22 of oxygen — in all, 225 atoms; or, more strictly speaking, equivalents. And this substance is so unstable as to decompose at quite moderate temperatures; as that to which the outside of a joint of roasting meat is exposed. Possibly it will be objected that some inorganic compounds, as phosphuretted hydrogen, chloride of nitrogen, and the nitrogen-explosives in general, are more decomposable than most organic compounds. This is true. But the admission may be made without damage to the argument. The proposition is not that all simple combinations are more stable than all complex ones. To establish our inference it is necessary only to show that, as an average fact, the simple combinations can exist at a higher temperature than the complex ones. And this is beyond question. Thus it is manifest that the present chemical heterogeneity of the Earth's surface, and of the bodies upon it, has arisen by degrees as the decrease of heat has permitted; and that it has shown itself in three forms: — first, in the multiplication of chemical compounds; second, in the greater number of different elements contained in the more modern of these compounds; and third, in the higher and more varied multiples in which these more numerous elements combine.

Without specifying them, it will suffice just to name the meteorologic processes eventually set up in the Earth's atmosphere, as further illustrating the alleged law. They equally display that destruction of a homogeneous state which results from unequal exposure to incident forces.

§152. Take a mass of unorganized but organizable matter — either the body of one of the lowest living forms, or the germ of one of the higher: both comparatively homogeneous. Consider its circumstances. Either it is immersed in water or air or is contained within a parent organism. Wherever placed, however, its outer and inner parts stand differently related to surrounding agencies — nutriment, oxygen, and the various stimuli. But this is not all. Whether it lies quiescent at the bottom of a pool or on the leaf of a plant; whether it moves through the water preserving some definite attitude; or whether it is in the inside of an adult; it equally happens that certain parts of its surface are more exposed to surrounding agencies than other parts — in some cases more exposed to light, heat, or oxygen, and in other cases to the maternal tissues and their contents. Hence must follow the loss of its original equilibrium. This may take place in one of two ways. Either the disturbing forces may be such as to over-balance the affinities of the organic elements, and there results decomposition; or, as ordinarily occurs, such changes are induced as do not destroy the organic compounds but only modify them: the parts most exposed to the modifying forces being most modified. To elucidate this a few cases are required.

Observe first what appear to be exceptions. Certain minute animal forms present either no appreciable differentiations or differentiations so obscure as to be made out with great difficulty. Concerning these forms, however, note the fact that in all cases (some say in nearly all) the presence of a nucleus shows conformity to the general law, since it implies a contrast between the innermost protoplasm and the protoplasm surrounding it. But let us pass on to the seemingly exceptional fact that the surrounding protoplasm does not exhibit the kind of differentiation between inner and outer above alleged. To this objection, there immediately presents itself the answer that this homogeneous body-substance does not become heterogeneous because its parts are not subject to any permanent heterogeneity of conditions: it has no fixed surface. In all members of the lowest group, Proteomyxa, the protoplasm continually protrudes itself, now in thicker now in thinner processes — pseudopodia; proved to have no limiting membranes by often coalescing. These, when they touch fragments of nutriment, contract and draw them into the mass of the body; so that what was just before external now becomes internal. Thus there are no fixed relations of parts and therefore no differentiations. And it is noteworthy that in certain of the Amoebae, less excursive than others of the type in the movements of their substance, we see an incipient differentiation: sometimes there is an investing film, "delicate and evanescent," implying that an outer part which is for a short time stationary, begins to be differentiated. Perceiving, then, that this apparent exception is in fact a verification, we go on to observe that permanent relations of inner and outer are followed by permanent differentiations. Elsewhere (Essays, i, 439) I have quoted from Sachs various proofs that a portion of protoplasm, whether normally detached, as in a spore, or abnormally detached, as by a rupture, forthwith becoming globular, at once acquires a surface denser than the interior; and Kerner similarly describes the protoplasm of a zoospore as "fixing itself and putting on a delicate cell-wall." These cases, joined with those of various Protozoa which, ceasing their active changes of form, pass into a resting stage and become enclosed in a cyst, and joined with the cases of Protophyta, like Sphaerella nivalis or "Red Snow," which, in its young stage ovoid, flagellate, locomotive, and secreting a skin, presently passes into a resting stage and becomes spherical and covered by a substantial cell-membrane, yield clear evidence that in these lowest types there is a lapse from a more homogeneous state into a less homogeneous state. And throughout the higher Protozoa and Protophyta, the primary contrast is between cell-membrane and cell-contents — between the part exposed to environing forces and the part sheltered from them.

The transition — the most important transition which the organic world presents — between the simple forms above exemplified and those compound forms in which a number of such are united into a colony, is well seen in certain minute algae, Pandorina and Eudorina: each being a spherically-arranged colony of sixteen or thirty-two members. In this first advance from unicellular types to multicellular types we find conformity to the general law in so far that the hollow sphere conspicuously displays the primary contrast between outer and inner; a primitive amorphous cluster has undergone a marked differentiation of parts corresponding to the difference of conditions. Still more instructive is the evidence furnished by types slightly in advance of these — Pleodorina and Volvox; the first consisting of some 128 cells and the second of 10,000 or more. Hollow spheres like the foregoing, they present in common the significant trait that, revolving, as they do, on a constant axis and moving forward approximately in the line of that axis, their two ends are exposed to slightly different conditions, and the primitive homogeneity of the members of the colony has, in consequence, lapsed into appropriate heterogeneity. These ciliated alga-cells, whether living singly or joined into groups, severally have a minute red speck which is proved to be sensitive to light, and causes motion towards it. Now in these compound forms just named, the eye-spots are more developed in those cells forming the anterior part of the spherical colony-cells which also carry on more actively the nutritive function; while those cells which form the posterior part of the sphere, and carry on the reproductive function, have smaller eye-spots. On passing to the animal kingdom (which at its root is so little differentiated from the vegetal kingdom that there are unsettled disputes respecting the inclusion of the lowest forms in the one or the other) we meet with parallel illustrations. The nucleated cell, which is the common starting point for all organisms, animal and vegetal, presents us as before with the primary contrast between inner and outer. And as in the multicellular plants so in the multicellular animals, a like primary contrast is forthwith repeated in the initial clusters of cells. Produced by the repeated fissions of the primitive germ-cell, each such cluster presently forms itself into a hollow sphere: the "cleavage cavity" being manifestly homologous with the cavity of the Volvox-sphere.* In simple types of Metazoa, as the hydroid polyps, the blastula, being thus established in conformity with the primary contrast of conditions, there presently begins a secondary differentiation which, like that we have seen in the Volvox but in a more pronounced manner, answers to the secondary contrast of conditions; for this spherical assemblage of cells becomes ovoid, and by the aid of its cilia moves through the water broad end foremost: the lapse from homogeneity of form being in some cases made more pronounced by the assumption of a sausage-shape. Simultaneously the component cells of the two ends become unlike in character. A far more marked differentiation, or lapse into greater heterogeneity, is seen when this single-layered spheroid of ciliated cells is changed into a double-layered spheroid by introversion of one side: a sack with the mouth sewn up and the bottom thrust in as far as it will go, serving to illustrate the relations of parts. Hence results the gastrula with its ectoderm and endoderm; severally playing contrasted parts in subsequent development. So that at successive stages there is repeated this rise of a contrast of structures answering to a contrast of conditions — that which occurs in the simple cell, that which occurs in the hollow sphere of such cells, and that which occurs in the double-walled sphere.

<* I may remark in passing that in the one case (and possibly by inheritance in the other) this formation of a hollow sphere is the result of the more rapid growth of the outer parts than the inner parts of a solid group. Being dependent for nutrition on light and carbon-dioxide in the water, the outside components of a Volvox (either the cells or the chlorophyll in each cell) have a great advantage over the cells or portions of cells which are more centrally placed; and it needs but to consider what happens if the periphery of a sphere increases at a proportionately greater rate than its contents to see that it must either leave the contents behind or draw them after it and become hollow. An analogous effect of excessive peripheral growth may occasionally be seen exempted when, after a dry fit during which potatoes have not grown much, there comes rain and a rapid increase of bulk; this being the explanation of the fact that in very large potatoes there is not uncommonly a split in the interior, caused by the strain which the disproportionate growth of the periphery necessarily causes.>

Illustrations presenting the law under another aspect — one from each organic kingdom — are instructive. The ciliated germ or planula of a Zoophyte which, during its locomotive stage, is distinguishable only into outer and inner tissues, no sooner becomes fixed than its upper end begins to assume a different structure from its lower. The disc-shaped gemmae of the Marchantia, originally alike on both surfaces, and falling at random with either side uppermost, immediately begin to develop rootlets on their under sides and stomata on their upper sides: a fact proving beyond question, that this primary differentiation is determined by this fundamental contrast of conditions.

Of course in the germs of higher organisms, the metamorphoses immediately due to the instability of the homogeneous, are soon masked by those due to the assumption of the hereditary type. Even in the early stages above described there are to be traced modifications thus originating. Even before the primary cell-multiplication begins, there is said to be an observable distinction between the two poles of the egg-cell, foreshadowing the different germ-layers. Of course as development progresses assumption of the transmitted type of structure quickly obscures these primary lapses from homogeneity; though for some time the fundamental relations of inner and outer are recognizable in the differentiations. But what has been said suffices to establish the alleged general truth. It is enough that incipient organisms, setting out from relatively homogeneous arrangements, forthwith begin to fall into relatively heterogeneous ones. It is enough that the most conspicuous differentiations which they display, correspond to the most marked differences of conditions to which their parts are subject. It is enough that the habitual contrast between outside and inside, which we know is produced in inorganic masses by unlikeness of exposure to incident forces, is paralleled by the first contrast which makes its appearance in all organic masses.

It remains to point out that in the assemblage of organisms constituting a species, the principle enunciated is no less traceable. We have abundant materials for the induction that each species will not remain uniform — is ever becoming to some extent multiform; and there is ground for the deduction that this lapse from homogeneity to heterogeneity is caused by the subjection of its members to unlike circumstances. Tending ever to spread from its original habitat into adjacent habitats, each species must have its peripheral parts subject to sets of forces unlike those to which its central parts are subject, and so must tend to have its peripheral members made different from its central members.

§153. Among mental phenomena full establishment of the alleged law would involve an analysis too extensive for the occasion. To show satisfactorily how states of consciousness, relatively homogeneous, become heterogeneous through differences in the changes wrought by different external forces, would require us to trace out the organization of early experiences. Without here attempting this it must suffice to set down the conclusions to be drawn.

The development of intelligence is, under one of its chief aspects, a classifying of the unlike things previously confounded together — a formation of sub-classes and sub-sub-classes, until the once confused aggregate of objects known, is resolved into an aggregate which unites great heterogeneity among its multiplied groups, with complete homogeneity among the members of each group. On following through ascending grades of creatures, the genesis of that vast structure of knowledge acquired by sight, we see that in the first stage, where eye-specks suffice only for discriminating light from darkness, there can be no classifications of objects seen, save those based on the manner in which light is obstructed, and the degree in which it is obstructed. By such undeveloped visual organs, the shadows perceived would be merely distinguished into those of the stationary objects which the creature passed during its own movements, and those of the moving objects which came near while it was at rest; so that the extremely general classification of visible things into stationary and moving, would be the earliest formed. A kindred step follows. While the simplest eyes cannot distinguish between an obstruction of light caused by a small object close to, and an obstruction caused by a large object at some distance, eyes a little more developed can distinguish them; whence must result a vague differentiation of the class of moving objects into the nearer and the more remote. Further developments which make possible a better estimation of distances by adjustment of the optic axes, and those which, through enlargement and subdivision of the retina, make possible the discrimination of shapes, must give greater definiteness to the classes already formed, and subdivide these into smaller classes, consisting of objects less unlike. In every infant may be traced the analogous transformation of a confused aggregate of impressions of surrounding things, not recognized as differing in their distances, sizes, and shapes, into separate classes of things unlike one another in these and various other respects. And in both cases the change from this first indefinite, incoherent, and comparatively homogeneous consciousness, to a definite, coherent, and heterogeneous one, is due to differences in the actions of incident forces on the organism. These brief indications must suffice. Probably they will give adequate clue to an argument by which each reader may satisfy himself that the course of mental evolution offers no exception to the general law. In further aid of such an argument, I will here add an illustration which is comprehensible apart from the process of mental evolution as a whole.

It has been remarked (I am told by Coleridge) that with the advance of language, words which were originally alike in their meanings acquire unlike meanings — a change he expressed by the formidable word "de-synonymization." Among indigenous words this loss of equivalence cannot be clearly shown; because in them the divergences of meaning began before the dawn of literature. But among words that have been coined, or adopted from other languages, since the writing of books commenced, it is demonstrable. By the old divines, miscreant was used in its etymological sense of unbeliever; but in modern speech it has entirely lost this sense. Similarly with evil-doer and malefactor. Exactly synonymous as these are by derivation, they are no longer synonymous by usage. By a malefactor we now under stand a convicted criminal, which is far from being the acceptation of evil-doer. The verb produce bears in Euclid its primary meaning — to prolong or draw out; but the now largely-developed meanings of produce, have little in common with the meanings of prolong, or draw out. In the Church of England liturgy an odd effect now results from the occurrence of prevent in its original sense — to come before, instead of its modern specialized sense — to come before with the effect of arresting. But the most conclusive cases are those in which the contrasted words consist of the same parts differently combined, as in go under and undergo. We go under a tree, and we undergo a pain. But though, if analytically considered, the meanings would be the same were the words transposed, habit has so far modified their meanings that we could not without absurdity speak of undergoing a tree and going under a pain. Many such instances show that between two words which are originally of like force, an equilibrium cannot be maintained. Unless they are daily used in exactly equal degrees, in exactly similar relations (which is infinitely improbable), there necessarily aries a habit of associating one rather than the other with particular acts, or objects. Such a habit once commenced, becomes confirmed; and gradually their homogeneity of meaning disappears.

Should any difficulty be felt in understanding how these mental changes exemplify a law of physical transformations that are wrought by physical forces, it will disappear on contemplating acts of mind as nervous functions. It will be seen that each loss of equilibrium above instanced, is a loss of functional equality between some two elements of the nervous system. And it will be seen that, as in other cases, this loss of functional equality is due to differences in the incidence of forces.

§154. Masses of men, in common with all other masses, show a like proclivity similarly caused. Small combinations and large societies equally manifest it; and in the one, as in the other, both governmental and industrial differentiations are initiated by it. Let us glance at the facts under these heads.

A business-partnership, balanced as the authorities of its members may theoretically be, presently becomes a union in which the authority of one partner is tacitly recognized as greater than that of the other or others. Though the shareholders have given equal powers to the directors of their company, inequalities of power soon arise among them; and often the supremacy of some one director grows so marked, that his decisions determine the course which the board takes. Nor in associations for political, charitable, literary, or other purposes, do we fail to find a like process of division into dominant and subordinate parties; each having its leader, its members of less influence, and its mass of uninfluential members. These minor instances in which unorganized groups of men, standing in homogeneous relations, may be watched gradually passing into organized groups of men standing in heterogeneous relations, give us key to social inequalities. Barbarous and civilized communities are alike characterized by separation into classes, as well as by separation of each class into more important and less important units; and this structure is the gradually-consolidated result of a process like that daily exemplified in trading and other combinations. So long as men are constituted to act on one another, either by physical force or by force of character the struggles for supremacy must finally be decided in favour of some class or some one; and the difference once commenced must tend to become ever more marked. Its unstable equilibrium being destroyed, the uniform must gravitate with increasing rapidity into the multiform. And so supremacy and subordination must establish themselves, as we see they do, throughout the whole structure of a society, from the great class-divisions pervading its entire body, down to village cliques, and even down to every posse of schoolboys. Probably it will be objected that such changes result, not from the homogeneity of the original aggregations, but from their non-homogeneity — from certain slight differences existing among their units at the outset. This is doubtless the proximate cause. In strictness, such changes must be regarded as transformations of the relatively homogeneous into the relatively heterogeneous. But an aggregation of men absolutely alike in their endowments, would eventually undergo a similar transformation. For in the absence of uniformity in the lives severally led by them — in their occupations, physical conditions, domestic relations, and trains of thought and feeling — there must arise differences among them; and these must eventually initiate social differentiations. Even inequalities of health caused by accidents will, by entailing inequalities of physical and mental power, disturb the exact balance of mutual influences among the units; and the balance once disturbed, will inevitably be lost.

Turning to the industrial organization, and noting that its division into regulative and operative is primarily determined, like the preceeding, by differences of power (women and slaves being the first working classes); admitting, too, that even among savages some small specializations arise from individual aptitudes; we go on to observe that the large industrial divisions into which societies gravitate, are due to unlikenesses of external circumstances. Such divisions are absent until such unlikenesses are established. Nomadic tribes do not permanently expose any groups of their members to special local conditions; nor does a stationary tribe, when occupying only a small area, maintain from generation to generation marked contrasts in the local conditions of its members; and in such tribes there are no decided economic differentiations. But a community which, by conquest, or otherwise, has overspread a large tract, and has become so far settled that its members live and die in their respective districts, keeps its several sections in different circumstances; and then they no longer remain alike in their occupations. Those who live dispersed continue to hunt or cultivate the earth; those who spread to the sea-shore fall into maritime occupations; while the inhabitants of some spot chosen, perhaps for its centrality, as one of periodic assemblage, become traders, and a town springs up. In the adaptations of these social units to their respective functions, we see a progress from uniformity to multiformity caused by unlike incidence of forces. Later in the process of social evolution these local adaptations are greatly multiplied. Differences in soil and climate, cause the rural inhabitants in different parts of the kingdom to have their occupations partially specialized, and to be come known as chiefly producing cattle, or sheep, or wheat, or oats, or hops, or fruit. People living where coal-fields are discovered are transformed into colliers; Cornishmen take to mining because Cornwall is metalliferous; and iron-manufacture is the dominant industry where iron-stone is plentiful. Liverpool has taken to importing cotton, because of its proximity to the district where cotton-goods are made; and for analogous reasons Hull has become the chief port at which foreign wools are brought in. Thus in general and in detail, industrial heterogeneities of the social organism primary depend on local influences. Those divisions of labour which, under another aspect, were interpreted as due to the setting up of motion in the directions of least resistance (§80), are here interpreted as due to differences in the incident forces; and the two interpretations are quite consistent with each other. For that which in each determines the direction of least resistance, is the distribution of the forces to be overcome; and hence unlikenesses of distribution in separate localities, entails unlikenesses in the lines of human actions in those localities — entails industrial differentiations.

§155. It has still to be shown that this general truth is demonstrable a priori — that the instability of the homogeneous is a corollary from the persistence of force. Already this has been tacitly implied, but here it will be proper to expand the tacit implication into definite proof.

On striking a mass of matter with such force as either to indent it or make it fly to pieces, we see both that the blow affects differently its different parts, and that the differences are consequent on the unlike relations of its parts to the force impressed. The part struck is driven in towards the centre of the mass. It thus compresses, and tends to displace, the more centrally situated portions. These, however, cannot be compressed or thrust out of their places without pressing on surrounding portions. And when the blow is violent enough to fracture the mass, we see, in the radial dispersion of the fragments, that the original momentum has been divided into numerous minor momenta, unlike in their directions. We see that the parts are differently affected by the disruptive force, because they are differently related to it in their directions and attachments — that the effects being the joint products of the force and the conditions cannot be alike in parts which are differently conditioned. A body on which radiant heat is falling, exemplifies this truth still more clearly. Take the simplest case — that of a sphere. While the part nearest to the radiating centre receives the rays at right angles, the rays strike the other parts of the exposed side at all angles from 90° down to 0°. The molecular vibrations propagated through the mass from the surface which receives the heat, proceed inwards at angles differing for each point. Further, the interior parts reached by the vibrations proceeding from all points of the heated side, must be dissimilarly affected in proportion as their positions are dissimilar. So that whether they be on the recipient area, in the middle, or at the remote side, the constituent molecules are thrown into states of vibration more or less unlike one another.

But now, what is the ultimate meaning of the conclusion that a force produces different changes throughout a uniform mass, because the parts of the mass stand in different relations to the force? Fully to understand this, we must contemplate each part as simultaneously subject to other forces — those of gravitation, of cohesion, molecular motion, etc. The effect wrought by an additional force, must be a resultant of it and the forces already in action. If the forces already in action on two parts of any aggregate, are different in their resultant directions, the effects produced on these two parts by equal additional forces must be different in their directions. Why must they be different? Because such unlikeness as exists between the two sets of factors, is made by the presence in the one of some specially-directed force that is not present in the other; and that this force will produce an effect, rendering the total result in the one case unlike that in the other, is a necessary corollary from the persistence of force. Still more manifest does it become that the dissimilarly-placed parts of any aggregate must be dissimilarly modified by an incident force, when we remember that the quantities of the incident force to which they are severally subject, are not equal, as above supposed, but are nearly always unequal. Look again at the above examples. The amounts of any external radiant force which the different parts of an aggregate receive, are widely contrasted: we have the contrast between the quantity falling on the side next the radiating centre, and the quantity, or rather no quantity, falling on the opposite side; we have contrasts in the quantities received by differently-placed areas on the exposed side; and we have endless contrasts between the quantities received by the various parts of the interior. Similarly when mechanical force is expended on any aggregate, either by collision, continued pressure, or tension, the amounts of strain distributed throughout the mass are manifestly unlike for unlike positions. And it is obvious that ordinary chemical action affects surface more than centre, and often one part of the surface more than another. But to say the different parts of an aggregate receive different quantities of any force capable of changing them, is to say that if they were before homogeneous they must be rendered to a proportionate extent heterogeneous; since, force being persistent, the different quantities of it falling on the different parts, must work in them different quantities of effect-different changes. Yet one more kindred deduction is required to complete the argument. Even apart from the action of any external force, the equilibrium of a homogeneous aggregate must be destroyed by the unequal actions of its parts on one another. That mutual influence which produces aggregation (not to mention other mutual influences) must work different effects on the different parts; since they are severally exposed to it in unlike amounts and directions. This will be clearly seen on remembering that the portions of which the whole is made up, may be severally regarded as minor wholes; that on each of these minor wholes, the action of the entire aggregate then becomes an external incident force; that such external incident force must, as above shown, work unlike changes in the parts of any such minor whole; and that if the minor wholes are severally thus rendered heterogeneous, the entire aggregate is rendered heterogeneous.

The instability of the homogeneous is thus deducible from that primordial truth which underlies our intelligence. One stable homogeneity only, is hypothetically possible. If centres of force, absolutely uniform in their powers, were diffused with absolute uniformity through unlimited space, they would remain in equilibrium. This however, though a verbally intelligible supposition, is one that cannot be represented in thought; since unlimited space is inconceivable. But all finite forms of the homogeneous — all forms of it which we can know or conceive, must inevitably lapse into heterogeneity; and the less heterogeneous must lapse into the more heterogeneous. In three several ways does the persistence of force necessitate this. Setting external agencies aside, each unit of a homogeneous whole must be differently affected from any of the rest by the aggregate action of the rest upon it. The resultant force exercised by the aggregate on each unit, being in no two cases alike in both amount and direction, and usually not in either, any incident force, even if uniform in amount and direction, cannot produce like effects on the units. And as the various positions of the parts in relation to any incident force, prevents them from receiving it in uniform amounts and directions, a further difference in the effects wrought on them inevitably arises.

One further remark is needed. The conclusion that the changes with which Evolution commences, are thus necessitated, has to be supplemented by the conclusion that these changes must continue. The absolutely homogeneous (supposing it to exist) must lose its equilibrium; and the relatively homogeneous must lapse into the relatively less homogeneous. That which is true of any total mass, is true of the parts into which it segregates. The uniformity of each such part must as inevitably be lost in multiformity, as was that of the original whole; and for like reasons. And thus the continued changes characterizing Evolution, in so far as they are constituted by the lapse of the homogeneous into the heterogeneous, and of the less heterogeneous into the more heterogeneous, are necessary consequences of the persistence of force.

[A small change in the definition of Evolution indicated in a note at the end of Chapter XVII of this part, must be recalled as involving a correlative change in this chapter. Here, as before, the required change, though already implied (page 367), has not been sufficiently emphasized, and lack of the emphasis invites misinterpretation. For reasons like those before given, the requisite explanations cannot be made in this place. The reader will find them in Appendix A.

Replies to certain criticisms on the general doctrine set forth in this chapter will be found in Appendix C.]

Chapter 20

The Multiplication of Effects

§156. To the cause of increasing complexity set forth in the last chapter, we have in this chapter to add another. Though secondary in order of time, it is scarcely secondary in order of importance. Even in the absence of the cause already assigned, it would necessitate a change from the homogeneous to the heterogeneous; and joined with it, it makes this change both more rapid and more involved. To come in sight of it we have but to pursue a step further that conflict between force and matter already delineated. Let us do this.

As already shown, when the components of a uniform aggregate are subject to a uniform force, they being differently conditioned, are differently modified. But while we have contemplated the various parts of the aggregate as undergoing unlike changes, we have not yet contemplated the unlike changes simultaneously produced on the various parts of the incident force. These must be as numerous as the others. In differentiating the parts on which it falls in unlike ways, the incident force must itself be correspondingly differentiated. Instead of being as before, a uniform force, it must thereafter be a multiform force — a group of dissimilar forces. A few illustrations will make this truth manifest.

In the case, lately cited, of a body shattered by violent collision, besides the change of the homogeneous mass into a heterogeneous group of scattered fragments, there is a change of the homogeneous momentum into a group of momenta, heterogeneous in both amounts and directions. Similarly with the forces we know as light and heat. After the dispersion of these by a radiating body towards all points, they are re-dispersed towards all points by the bodies on which they fall. Of the Sun's rays, issuing from him on every side, some few strike the Moon. Reflected at all angles from the Moon's surface, some few of these strike the Earth. By a like process the few which reach the Earth are again diffused: some into space, some from object to object. And on each occasion, such portions of the rays as are transmitted instead of reflected, undergo refractions or other changes which equally destroy their uniformity. More than this is true. By conflict with matter a uniform force is in part changed into forces differing in their kinds. When one body is struck against another, that which we usually regard as the effect, is a change of position or motion in one or both bodies. But this is a very incomplete view of the matter. Besides the visible mechanical result, sound is produced — a vibration in one or both bodies and in the surrounding air; and under some circumstances we call this the effect. Moreover, the air has not simply been made to vibrate; it has had currents raised in it by the transit of the bodies. Further, if there is not that great structural change which we call fracture, there is a disarrangement of the particles of the two bodies around their point of collision; amounting in some cases to a visible condensation. Yet more, this condensation is accompanied by genesis of heat. In some cases a spark — that is, light — results from the incandescence of a portion struck off. Thus by the original mechanical force expended in the collision, at least five kinds of forces have been produced. Take, again, the lighting of a candle. Primarily, this is a chemical change consequent on a rise of temperature. The process of combination having once been set going by extraneous heat, there is a continued formation of carbon dioxide, water, etc. Along with this process of combination there is a production of heat; there is a production of light; there is an attending column of hot gases generated; there are currents caused in the surrounding air. Nor does the decomposition of one force into many forces end here. Each of the several changes worked becomes the parent of further changes. The carbon dioxide formed will eventually combine with some base; or under the influence of sunshine give up its carbon to the leaf of a plant. The water will modify the hygrometric state of the air around; or, if the current of hot gases containing it comes against a cold body, will be condensed: altering the temperature, and perhaps the chemical state, of the surface it covers. The heat given out melts the subjacent tallow and expands whatever else it warms. The light, falling on various substances, calls forth from them reactions by which it is decomposed, and divers colours are thus produced. Similarly with these secondary actions, which may be traced out into ever-multiplying ramifications, until they become too minute to be appreciated. Universally, then, the effect is more complex than the cause. Whether the aggregate on which it falls be homogeneous or otherwise, an incident force is transformed by the conflict into a number of forces that differ in their amounts, or directions, or kinds; or in all these respects. And of this group of variously-modified forces, each ultimately undergoes a like transformation.

Let us now mark how the process of evolution is furthered by this multiplication of effects. An incident force decomposed by the reactions of a body into a group of unlike forces, becomes the cause of a secondary increase of multiformity in the body which decomposes it. By the reactions of the various parts, differently modified as we have seen they must be, the incident force itself must be divided into differently modified parts. Each differentiated division of the aggregate thus becomes a centre from which a differentiated division of the original force is again diffused. And since unlike forces must produce unlike results, each of these differentiated forces must produce, throughout the aggregate, a further series of differentiations. This secondary cause of the change from homogeneity to heterogeneity, obviously becomes more potent in proportion as the heterogeneity increases. When the parts into which any evolving whole has segregated itself, have diverged widely in nature, they will necessarily react very diversely on any incident force — they will divide an incident force in to so many strongly contrasted groups of forces. And each of them becoming the centre of a quite distinct set of influences, must add to the number of distinct secondary changes wrought throughout the aggregate. Yet another corollary must be added. The number of unlike parts of which an aggregate consists, is an important factor in the process. Every additional specialized division is an additional centre of specialized forces, and must be a further source of complication among the forces at work throughout the mass — a further source of heterogeneity. The multiplication of effects must proceed in geometrical progression.

§157. The scattered parts of an irregular nebula in course of being drawn together or integrated, cannot display in a definite manner the secondary traits of evolution: these presuppose an aggregate already formed. We can say only that the half-independent components, each attracted by all and all by each, exhibit in their various momenta, different in their amounts and directions, a multiplication of effects produced by a single gravitative force.

But assuming that the integrative process has at length generated a single mass of nebulous matter, then the simultaneous condensation and rotation show us how two effects of the aggregative force, at first but slightly divergent, become at last widely differentiated. An increase of oblateness in this spheroid must take place through the joint action of these two forces, as the bulk diminishes and the rotation grows more rapid; and this we may set down as a third effect. The genesis of heat, accompanying augmentation of density, is a consequence of yet another order — a consequence by no means simple; since the various parts of the mass, being variously condensed, must be variously heated. Acting throughout a gaseous spheroid, of which the parts are unlike in their temperatures, the forces of aggregation and rotation must work a further series of changes: they must set up circulating currents, both general and local. At a later stage light as well as heat will be generated. Thus without dwelling on the likelihood of chemical combinations and electric disturbances, it is manifest that, supposing matter to have originally existed in a diffused state, the once uniform force which caused its aggregation, must have become gradually divided into different forces; and that each further stage of complication in the resulting aggregate, must have initiated further subdivisions of this force — a further multiplication of effects, increasing the previous heterogeneity.

This section of the argument may however be adequately sustained without having recourse to any such hypothetical illustrations as the foregoing. The astronomical attributes of the Earth will, even by themselves, suffice for our purpose. Consider first the effects of its rotation. There is the oblateness of its form; there is the alternation of day and night; there are certain constant marine currents; and there are certain constant aerial currents. Consider next the secondary series of consequences due to the divergence of the Earth's plane of rotation from the plane of its orbit. The many variations of the seasons, both simultaneous and successive, which pervade its surface, are thus caused. External attraction of the Moon and Sun acting on the equatorial protuberance of this rotating spheroid with inclined axis, produces the motion called nutation, and that slower and larger one from which follows the precession of the equinoxes, with its several sequences. And then, by this same force, are generated the tides, aqueous and atmospheric.

Perhaps, however, the simplest way of showing the multiplication of effects among phenomena of this order, will be to set down the influences of any member of the Solar System on the rest. A planet directly produces in neighbouring planets certain appreciable perturbations, complicating those otherwise produced in them; and in the remoter planets it directly produces certain less visible perturbations. Here is a first series of effects. But each of the perturbed planets is itself a source of perturbations — each directly affects all the others. Hence, planet A having drawn planet B out of the position it would have occupied in A's absence, the perturbations which B causes are different from what they would else have been; and similarly with C, D, E, etc. Here then is a secondary series of effects; far more numerous though far smaller in their amounts. As these indirect perturbations must to some extent modify the movements of each planet, there results from them a tertiary series; and so on in ever multiplying and diminishing waves throughout the entire system.

§158. If the Earth was formed by the concentration of diffused matter, it must at first have been incandescent; and whether the nebular hypothesis be accepted or not, this original incandescence of the Earth may now be regarded as inductively established — or, if not established, at least rendered so probable that it is a generally admitted geological doctrine. Several results of the gradual cooling of the Earth — as the formation of a crust, the solidification of sublimed elements, the precipitation of water, etc. — have been already noticed, and I again refer to them merely to point out that they are simultaneous effects of the one cause, diminishing heat. Let us now, however, observe the multiplied changes afterwards arising from the continuance of this one cause. The Earth, falling in temperature, must contract. Hence the solid crust at any time existing is presently too large for the shrinking nucleus, and, being unable to support itself, inevitably follows the nucleus. But a spheroidal envelope cannot sink down into contact with a smaller internal spheroid, without disruption: it will run into wrinkles as the rind of an apple does when the bulk of its interior decreases from evaporation. As the cooling progresses and the envelope thickens, the ridges consequent on these contractions must become greater, rising ultimately into hills and mountains; and the later systems of mountains thus produced must not only be higher, as we find them to be, but must be longer, as we also find them to be. Thus, leaving out of view other modifying forces, we see what immense heterogeneity of surface arises from the one cause, loss of heat — a heterogeneity which the telescope shows us to be paralleled on the Moon, where aqueous and atmospheric agencies have been absent. But we have yet to notice another kind of heterogeneity of surface, simultaneously caused. While the Earth's crust was thin, the ridges produced by its contractions must not only have been small in height and length, but the tracts between them must have rested with comparative smoothness on the subjacent liquid spheroid; and the water in those arctic and antarctic regions where it first condensed, must have been evenly distributed. But as fast as the crust grew thicker and gained corresponding strength, the lines of fracture from time to time caused in it, occurred at greater distances apart; the intermediate surfaces followed the contracting nucleus with less uniformity; and there consequently resulted larger areas of land and water. If any one, after wrapping an orange in tissue paper and observing both how small are the wrinkles and, how evenly the intervening spaces lie on the surface of the orange, will then wrap it in thick cartridge-paper, and note both the greater height of the ridges and the larger spaces throughout which the paper does not touch the orange, he will see that as the Earth's solid envelope thickened, the areas of elevation and depression became greater. In place of islands more or less homogeneously scattered throughout an all-embracing sea, there must have gradually arisen heterogeneous arrangements of continent and ocean, such as we now know. These simultaneous changes in the ex tent and in the elevation of the lands, involved yet another species of heterogeneity — that of coast-line. A tolerably even surface raised out of the ocean will have a simple, regular sea-margin; but a surface varied by table-lands and intersected by mountain-chains, will, when raised out of the ocean, have an outline extremely irregular, alike in its leading features and in its details. Thus endless is the accumulation of geological and geographical results brought about by this one cause — escape of the Earth's primitive heat.

When we pass from the agency which geologists term igneous, to aqueous and atmospheric agencies, we see a like ever-growing complication of effects. The denuding actions of air and water have, from the beginning, been modifying every exposed surface: everywhere working many different changes. As already said (§69) the original source of those gaseous and fluid motions which effect denudation, is the solar heat. The transformation of this into various modes of energy, according to the nature and conditions of the matter on which it falls, is the first stage of complication. The Sun's rays, striking at all angles a sphere that from moment to moment presented and withdrew different parts of its surface, and each of them for a different time daily throughout the year, would produce a considerable variety of changes even were the sphere uniform. But falling as they do on a sphere surrounded by an atmosphere containing wide areas of cloud, but which here unveils vast tracts of sea, there of level land, there of mountains, there of snow and ice, they cause in it countless different movements. Currents of air of all sizes, directions, velocities, and temperatures, are set up; as are also marine currents similarly contrasted in their characters. In this region the surface is giving off vapour; in that, dew is being precipitated; and in another, rain is descending — unlikenesses which arise from the changing ratio between the absorption and radiation of heat in each place. At one hour a rapid fall in temperature leads to the formation of ice, with an accompanying expansion throughout the moist bodies frozen; while at another a thaw unlocks the dislocated fragments of these bodies. And then, passing to a second stage of complication, we see that the many kinds of motion directly or indirectly caused by the Sun's rays, severally produce results which vary with the conditions. Oxidation, drought, wind, frost, rain, glaciers, rivers, waves, and other denuding agents effect disintegrations that are determined in their amounts and qualities by local circumstances. Acting on a tract of granite, such agents here work scarcely an appreciable effect; there cause exfoliations of the surface and a resulting heap of debris and boulders; and elsewhere, after decomposing the feldspar into a white clay, carry away this with the accompanying quartz and mica, and deposit them in separate beds, fluviatile or marine. When the exposed land consists of several unlike formations, sedimentary and igneous, changes proportionately more heterogeneous are wrought. The formations being disintegrable in different degrees, there follows an increased irregularity of surface. The areas drained by adjacent rivers being differently constituted, these rivers carry down to the sea unlike combinations of ingredients; and so sundry new strata of distinct compositions arise. And here, indeed, we may see very clearly how the heterogeneity of the effects increases in a geometrical progression with the heterogeneity of the object acted upon. Let us, for the fuller elucidation of this truth in relation to the inorganic world, consider what would follow from an extensive cosmical catastrophe — say a great subsidence throughout Central America. The immediate results would themselves be sufficiently complex. Besides the numberless dislocations of strata, the ejections of igneous matter, the propagation of earthquake vibrations many thousands of miles around, the loud explosions, and the escape of gases, there would be an inrush of the Atlantic and Pacific Oceans, a subsequent recoil of enormous waves, which would traverse both these oceans and produce myriads of changes along their shores, and corresponding atmospheric waves complicated by the currents surrounding each volcanic vent, as well as electrical discharges with which eruptions are accompanied. But these temporary effects would be insignificant compared with the permanent ones. The complex currents of the Atlantic and Pacific would be altered in their directions and amounts. The distribution of heat achieved by these currents would be different from what it is. The arrangement of the isothermal lines, not only on the neighbouring continents but even throughout Europe, would be changed. The tides would flow differently from what they do now. There would be more or less modification of the winds in their periods, strengths, directions, qualities; and rain would fall scarcely anywhere at the same times and in the same quantities as at present. In these many changes, each including countless minor ones, may be seen the immense heterogeneity of the results wrought out by one force, when that force expends itself on a previously complicated area: the implication being that from the beginning the complication has advanced at an increasing rate.

§159. We have next to trace throughout organic evolution, this same all-pervading principle. And here, where the transformation of the homogeneous into the heterogeneous was first observed, the production of many changes by one cause is least easy to demonstrate in a direct way. Heredity complicates everything. Nevertheless, by indirect evidence we may establish our proposition.

By way of preparation observe how numerous are the changes which any marked stimulus works on an adult organism — a human being for instance. An alarming sound or sight, besides impressions on the organs of sense and the nerves, may produce a start, a scream, a distortion of the face, a trembling consequent on general muscular relaxation, a burst of perspiration, and perhaps an arrest of the heart followed by syncope; and if the system be feeble, an illness with its long train of complicated symptom may set in. Similarly in cases of disease. A minute portion of the small-pox virus taken into the system will, in a severe case, cause, during the first stage, rigors, heat of skin, accelerated pulse, furred tongue, loss of appetite, thirst, epigastric uneasiness, vomiting, headache, pats in the back and limbs, muscular weakness, convulsions, delirium, etc.; in the second stage, cutaneous eruption, itching, tingling, sore throat, swelled fauces, salivation, cough, hoarseness, dyspnoea, etc.; and in the third stage, oedematous inflammations, pneumonia, pleurisy, diarrhoea, inflammation of the brain, ophthalmia, erysipelas, etc.: each of which enumerated symptoms is itself more or less complex. Now it needs only to consider that this working of many changes by one force on an adult organism, must be partially paralleled in an embryo-organism, to understand that in it too there must be a multiplication of effects, ever tending to produce increasing heterogeneity. Each organ as it is developed, serves, by its actions and reactions on the rest, to initiate new complexities. The first pulsations of the foetal heart must simultaneously aid the unfolding of every part. The growth of each tissue, by taking from the blood special proportions of elements, must modify the constitution of the blood; and so must modify the nutrition of all the other tissues. The distributive actions, implying as they do a certain waste, necessitate an addition to the blood of effete matters, which must influence the rest of the system, and perhaps, as some think, initiate the formation of excretory organs. The nervous connexions established among the viscera must further multiply their mutual influences. And so is it with every modification of structure — every additional part and every alteration in the ratios of parts. Proof of a more direct kind is furnished by the fact, that the same germ may be evolved into different forms according to circumstances. Thus, during its earliest stages, every germ is sexless — originates either male or female as the balance of forces acting on it determines. Again, there is the familiar truth that the larva of a working-bee will develop into a queen-bee if, before a certain period, it is fed after a manner like that in which the larvae of queen-bees are fed. Then there is the still more striking evidence furnished by ants and termites. Riley, Grassi, Haviland, and Hart, have shown that differences of nutrition not only originate the differences between males and females but also the different traits of solders, workers, and nurses.* Varying degree of nutrition, after initiating the unlikeness of sex, then determines the unlikenesses of external organs possessed by the various classes of sexless individuals. Next comes the evidence, still more directly relevant, supplied by the effects of castration. If the removal of certain organs prevents the development of certain other organs in remote parts of the system — in man the vocal structures, the beard, some traits of general form, some instincts and other mental characters — then it is clear that where these organs have not been removed, the presence of them determines the occurrence of these various changes of development, and doubtless many minor ones which are unobtrusive. Here the fact that one cause produces many effects in the course of organic evolution is indisputable. Doubtless we are, and must ever continue, unable to conceive those mysterious properties which make the germ when subject to fit influences undergo the special changes initiating, and mainly constituting, the transformations of an unfolding organism; though we may consistently suppose that they represent an infinite series of inherited modifications consequent on the instability of the homogeneous, the multiplication of effects, and one further factor still to be set forth. All here contended is that, given a germ possessing these mysterious properties, the evolution of an organism from it depends, in part, on that multiplication of effects which we have seen to be one cause of evolution in general, so far as we have yet traced it.

<* See Principles of Biology, Vol. I, pp. 680-8.>

When, leaving the development of single plants and animals, we pass to that of the Earth's Flora and Fauna, the course of the argument again becomes clear and simple. Though, as before admitted, the fragmentary facts Palaeontology has accumulated, do not clearly warrant us in saying that, in the lapse of geologic time, there have been evolved more heterogeneous organisms, and more heterogeneous assemblages of organisms; yet we shall now see that there must ever have been a tendency towards these results. We shall find that the production of many effects by one cause, which, as already shown, has been all along increasing the physical heterogeneity of the Earth, has further necessitated an increasing heterogeneity of its inhabiting organisms, individually and collectively. An illustration will make this clear.

Suppose that by upheavals, occurring, as they are known to do, at long intervals, the East Indian Archipelago were raised into a continent, and a chain of mountains formed along the axis of elevation. By the first of these upheavals, the plants and animals of Borneo, Sumatra, New Guinea, and the rest, would be subjected to slightly-modified sets of conditions. The climate of each would be altered in temperature, in humidity, and in its periodical variations, while the local differences would be multiplied. The modifications would effect, perhaps inappreciably, the entire Flora and Fauna of the region. The change of level would entail additional modifications, varying in different species, and also in different members of the same species, according to their distance from the axis of elevation. Plants growing only on the sea-shore in special localities, might become extinct. Others, living only in swamps of a certain humidity, would, if they survived at all, probably undergo visible changes of appearance. While more marked alterations would occur in some of the plants that spread over the lands newly raised out of the water. The animals and insects living on these modified plants, would themselves be in some degree modified by changes of food, as well as by changes of climate; and the modifications would be more marked where, from the dwindling or disappearance of one kind of plant, an allied kind was eaten. In the lapse of the many generations arising before the next upheaval, the sensible or insensible alterations thus produced in each species, would become organized — in all the races which survived there would be more or less adaptation to the new conditions. The next upheaval would superinduce further organic changes, implying wider divergences from the primary forms; and so repeatedly. Now, however, observe that this revolution would not be a substitution of a thousand modified species for the thousand original species; but in place of the thousand original species there would arise several thousand species, or varieties, or changed forms. Each species being distributed over an area of some extent, and tending continually to colonize the new area exposed, its different members would be subject to different sets of changes. Plants and animals migrating towards the equator would not be affected in the same way with others migrating from it. Those which spread towards the new shores, would undergo changes unlike the changes undergone by those which spread into the mountains. Thus, each original race of organisms would become the root from which diverged several races, differing more or less from it and from one another; and while some of these might subsequently disappear, probably more than one would survive into the next geologic period. Not only would certain modifications be thus caused by changes of physical conditions and food, but also, in some cases, other modifications caused by changes of habit. The fauna of each island, peopling, step by step, the newly-raised tracts, would eventually come in contact with the faunas of other islands; and some members of these other faunas would be unlike any creatures before seen. Herbivores meeting with new beasts of prey would, in some cases, be led into modes of defence or escape differing from those previously used; and simultaneously the beasts of prey would modify their modes of pursuit and attack. We know that when circumstances demand it, such changes of habit do take place in animals; and we know that if the new habits become the dominant ones, they must eventually in some degree alter the organization. Note, now, a further consequence. There must arise not simply a tendency towards the differentiation of each race of organisms into several races; but also a tendency to the occasional production of a somewhat higher organism. Taken in the mass, these divergent varieties, which have been caused by fresh physical conditions and habits of life, will exhibit alterations quite indefinite in kind and degree, and alterations that do not necessarily constitute an advance. Probably in most cases the modified type will be not appreciably more heterogeneous than the original one. But it must now and then occur that some division of a species, falling into circumstances which give it rather more complex experiences, and demand actions somewhat more involved, will have certain of its organs further differentiated in proportionately small degrees — will become slightly more heterogeneous. Hence, there will from time to time arise an increased heterogeneity both of the Earth's flora and fauna, and of individual races included in them. Omitting detailed explanations, and allowing for qualifications which cannot here be specified, it is sufficiently clear that geological mutations have all along tended to complicate the forms of life, whether regarded separately or collectively That multiplication of effects which has been a part-cause of the transformation of the Earth's crust from the simple into the complex, has simultaneously led to a parallel transformation of the Life upon its surface.*

<* Had this paragraph, first published in the Westminster Review in April, 1857, been written after the appearance of Mr. Darwin's work on The Origin of Species, instead of before, it would doubtless have been otherwise expressed. Reference would have been made to the process of "natural selection," as greatly facilitating the differentiations described. As it is, however, I prefer to let the passage stand in its original shape; partly because it seems to me that these successive changes of conditions would produce divergent varieties or species, apart from the influence of "natural selection" (though in less numerous ways as well as less rapidly); and partly because I conceive that in the absence of these successive changes of conditions, "natural selection" would effect comparatively little. Let me add that though these positions are not enunciated in The Origin of Species, yet a common friend gives me reason to think that Mr. Darwin would coincide in them.>

The deduction here drawn from the established truths of geology and the general laws of life, gains immensely in weight on finding it to be in harmony with an induction drawn from direct experience. Just that divergence of many races from one race, above described as continually occurring during geologic time, we know to have occurred during the pre-historic and historic periods, in man and domestic animals. And just that multiplication of effects which we concluded must have been instrumental to the first, we see has in great measure wrought the last. Single causes, as famine, pressure of population, war, have periodically led to further dispersions of men and of dependent creatures: each such dispersion initiating new modifications, new varieties. Whether all the human races be or be not derived from one stock, philology shows that in many cases a group of races, now easily distinguishable from one another, was originally one race — that the diffusion of one race into different regions and conditions of existence has produced many altered forms of it. Similarly with domestic animals. Though in some cases, as that of dogs, community of origin will perhaps be disputed, yet in other cases, as that of the sheep or the cattle of our own country, it will not be questioned that local differences of climate, food, and treatment, have transformed one original breed into many breeds, now become so far distinct as to produce unstable hybrids. Moreover, through the complication of effects flowing from single causes, we here find, what we before inferred, not only an increase of general heterogeneity, but also of special heterogeneity. While of the divergent divisions and subdivisions of the human race, many have undergone changes not constituting an advance; others have become more heterogeneous. The civilized European departs more widely from the mammalian archetype than does the Australian.

§160. A sense-impression does not expend itself in arousing some single state of consciousness; but the state of consciousness aroused is made up of various represented sensations connected by co-existence or sequence with the presented sensation. And that, in proportion as the grade of intelligence is high, the number of ideas suggested is great, may be readily inferred. Let us, however, look at the proof that here, too, each change is the parent of many changes and that the multiplication increases in proportion as the area affected is complex.

Were some hitherto unknown bird, driven by stress of weather from the remote north, to make its appearance on our shores, it would excite no speculation in the sheep or cattle amid which it alighted: a perception of it as a creature like those constantly flying about, would be the sole interruption of that dull current of consciousness which accompanies grazing and rumination. The cowherd, by whom we may suppose the exhausted bird to be presently caught, would probably gaze at it with some slight curiosity, as being unlike any he had before seen would note its most conspicuous markings, and vaguely ponder on the questions, where it came from, and how it came. By the sight of it, the village bird-stuffer would have suggested to him sundry forms to which it bore a little resemblance; would receive from it more numerous and more specific impressions respecting structure and plumage; would be reminded of other birds brought by storms from foreign parts; would tell who found them, who stuffed them, who bought them. Supposing the unknown bird taken to a naturalist of the old school, interested only in externals, (one of those described by Edward Forbes, as examining animals as though they were skins filled with straw,) it would excite in him a more involved series of mental changes. There would be an elaborate examination of the feathers, a noting of all their technical distinctions, with a reduction of these perceptions to certain equivalent written symbols; reasons for referring the new form to a particular family order, and genus would be sought out and written down; communications with the secretary of some society or editor of some journal, would follow; and probably there would be not a few thoughts about the addition of the ii to the describer's name, to form the name of the species. Lastly, in the comparative anatomist such a new species, should it have any marked internal peculiarity, might produce additional sets of changes — might suggest modified views respecting the relationships of the division to which it belonged; or, perhaps, alter his conceptions of the homologies and developments of certain organs; and the conclusions drawn might possibly enter as elements into still wider inquiries concerning the origin of organic forms.

From ideas let us turn to emotions. In a young child, a father's anger produces little else than vague fear — a sense of impending evil, taking various shapes of physical suffering or deprivation of pleasures. In elder children the same harsh words will arouse additional feelings: sometimes a sense of shame, of penitence, or of sorrow for having offended; at other times, a sense of injustice and a consequent anger. In the wife, yet a further range of feelings may come into existence — perhaps wounded affection, perhaps self-pity for ill-usage, perhaps contempt for groundless irritability, perhaps sympathy for some suffering which the irritability indicates, perhaps anxiety about an unknown misfortune which she thinks has produced it. Nor are we without evidence that among adults, the like differences of development are accompanied by like differences in the number of emotions aroused, in combination or rapid succession: the lower natures being characterized by that impulsiveness which results from the uncontrolled action of a few feelings; and the higher natures being characterized by the simultaneous action of many secondary feelings, modifying those first awakened.

Perhaps it will be objected that the illustrations here given, are drawn from the functional changes of the nervous system, not from its structural changes; and that what is proved among the first does not necessarily hold among the last. This must be admitted. Those, however, who recognize the truth that the structural changes are the slowly accumulated results of the functional changes, will readily draw the corollary that a part-cause of the evolution of the nervous system, as of other evolution, is this multiplication of effects which becomes ever greater as the development becomes higher.

§161. If the advance of Man towards greater heterogeneity, in both body and mind, is in part traceable to the production of many effects by one cause, still more clearly may the advance of Society towards greater heterogeneity be so explained.

Consider the growth of industrial organization. When some individual of a tribe displays unusual aptitude for making weapons, which were before made by each man for himself, there arises a tendency towards the differentiation of that individual into a maker of weapons. His companions, warriors and hunters all of them, severally wishing to have the best weapons that can be made, are certain to offer strong inducements to this skilled individual to make weapons for them. He, on the other hand, having both an unusual faculty, and an unusual liking, for making weapons (capacity and desire being commonly associated), is predisposed to fulfil these commissions on the offer of adequate rewards: especially as his love of distinction is also gratified. This first specialization of function, once commenced, tends ever to become more decided. On the side of the weapon-maker, continued practice gives increased skill. On the side of his clients, cessation of practice entails decreased skill. Thus this social movement tends to become more decided in the direction in which it was first set up; and the incipient heterogeneity is, on the average of cases, likely to become permanent for that generation, if no longer.

Such a differentiation has a tendency to initiate other differentiations. The advance described implies the introduction of barter. The maker of weapons has to be paid in such other articles as he agrees to take. Now he will not habitually exchange for one kind of article. He does not want mats only, or skins, or fishing-gear. He wants all these, and on each occasion will bargain for the particular things he then most needs. What follows? If among the members of the tribe there exist any slight differences of skill in the manufacture of these various things the weapon-maker will take from each one the thing which that one excels in making. But he who has bartered away his mats or his fishing-gear, must make other mats or fishing-gear for himself; and in so doing must, in some degree, further develop his aptitude. If such transactions are repeated, these specializations may become appreciable. And whether or not there ensue distinct differentiations of other individuals into makers of particular articles, it is clear that the one original cause produces not only the first dual effect, but a number of secondary dual effects, like in kind but minor in degree. This process, of which traces may be seen among groups of schoolboys, cannot well produce a lasting distribution of functions in an unsettled tribe; but where there grows up a fixed and multiplying community, it will become permanent, and increase with each generation. An addition to the number of citizens, involving a greater demand for every commodity, intensifies the functional activity of each specialized person or class; and this renders the specialization more definite where it exists, and establishes it where it is nascent. By increasing the pressure on the means of subsistence, a larger population again augments these results; since every individual is forced more and more to confine himself to that which he can do best, and by which he can gain most. And this industrial progress opens the way for further growth of population, which reacts as before. Under the same stimuli new occupations arise. Among competing workers, some discover better processes or better materials. The substitution of bronze for stone entails on him who first makes it a great increase of demand — so great an increase that presently all his time is occupied in making the bronze for the articles he sells, and he is obliged to depute the fashioning of these articles to others; so that eventually the making of bronze, thus differentiated from a pre-existing occupation, becomes an occupation by itself. But now mark the ramified changes which follow this change. Bronze soon replaces stone not only in the articles it was first used for, but in many others; and so affects the manufacture of them. Further, it affects the processes which such improved utensils subserve, and the resulting products — modifies buildings, carvings, dress, personal decorations. And all these changes react on the people-increase their manipulative skill, their intelligence, their comfort-refine their habits and tastes.

This increasing social heterogeneity that results from the production of many effects by one cause, cannot of Course be followed out. But leaving the intermediate phases of social development, let us take an illustration from its passing phase. To trace the effects of steampower, in its manifold applications to mining, navigation, and manufactures, would carry us into unmanageable detail. Let us confine ourselves to the latest embodiment of steam-power — the locomotive engine. This, as the proximate cause of our railway-system, has changed the face of the country, the course of trade, and the habits of the people. Consider, first, the complicated sets of changes that precede the making of every railway — the provisional arrangements, the meetings, the registration, the trial-section, the parliamentary survey, the lithographed plans, the books of reference, the local deposits and notices, the application to Parliament, the passing Standing-Orders Committee, the first, second, and third readings: each of which brief heads indicates a multiplicity of transactions, and a further development of sundry occupations, (as those of engineers, surveyors, lithographers, parliamentary agents, share-brokers,) and the creation of sundry others (as those of traffic-takers, reference-makers). Consider, next, the yet more marked changes implied in railway construction — the cuttings, embankings, tunnellings, diversions of roads; the building of bridges, viaducts, and stations; the laying down of ballast, sleepers, and rails; the making of engines, tenders, carriages, and wagons: which processes, acting upon numerous trades, increase the importation of timber, the quarrying of stone, the manufacture of iron, the mining of coal, the burning of bricks; institute a variety of special manufactures weekly advertised in the Railway Times; and call into being some new classes of workers-drivers, stokers, cleaners, plate-layers, signalmen. Then come the changes, more numerous and involved still, which railways in action produce on the community at large. The organization of every business is modified. Ease of communication makes it better to do directly what was before done by proxy; agencies are established where previously they would not have paid; goods are obtained from remote wholesale houses instead of near retail ones; and commodities are used which distance once rendered inaccessible. Rapidity and economy of carriage tend to specialize more than ever the industries of different districts — to confine each manufacture to the parts in which, from local advantages, it can be best carried on. Cheap distribution equalizes prices, and also, on the average, lowers prices: thus bringing divers articles within the reach of those before unable to buy them. At the same time the practice of travelling is immensely extended. People who before could not afford it, take annual trips to the sea, visit their distant relations, make tours, and so are benefited in body, feelings, and intellect. The prompter transmission of letters and of news produces further changes — makes the pulse of the nation faster. Yet more, there arises a wide dissemination of cheap literature through railway book-stalls, and of advertisements in railway carriages: both of them aiding ulterior progress. So that beyond imagination are the changes, thus briefly indicated, consequent on the invention of the locomotive engine.

It should be added that we here see more clearly than, ever, how in proportion as the area over which any influence extends becomes heterogeneous, the results are in a yet higher degree multiplied in number and kind. While among the uncivilized men to whom it was first known, caoutchouc caused but few changes, among ourselves the changes have been so many and varied that the history of them occupies a volume. Upon the small, homogeneous community inhabiting one of the Hebrides, the electric telegraph would produce, were it used, scarcely any results; but in England the results it produces are multitudinous.

Space permitting, the synthesis might here be pursued in relation to all the subtler products of social life. It might be shown how, in Science, an advance of one division presently advances other divisions — how Astronomy has been immensely forwarded by discoveries in Optics, while other optical discoveries have initiated Microscopic Anatomy, and greatly aided the growth of Physiology — how Chemistry has indirectly increased our knowledge of Electricity, Magnetism, Biology, Geology — how Electricity has reacted on Chemistry and Magnetism, developed our views of Light and Heat, and disclosed sundry laws of nervous action. But it would needlessly tax the reader's patience to detail, in their many ramifications, these various changes; so involved and subtle as to be followed with difficulty.

§162. After the argument which closed the last chapter, a parallel one here seems scarcely required. For symmetry's sake, however, it will be proper briefly to point out how the multiplication of effects, like the instability of the homogeneous, is a corollary from the persistence of force.

Things which we call different are things which react in different ways; and we can know them as different only by the differences in their reactions. When we distinguish bodies as hard or soft, rough or smooth, we mean that certain like muscular forces expended on them are followed by unlike reactive forces, causing unlike sets of sensations. Objects classed as red, blue, yellow etc., are objects which decompose light in contrasted ways; that is, we know contrasts of colour as contrasts in the changes produced in a uniform incident force. The proposition that the different parts of any whole must react differently on a uniform incident force, and must thus reduce it to a group of multiform forces, is in essence a truism. Suppose we reduce this truism to its lowest terms.

When, from unlikeness between the effects they produce on consciousness, we predicate unlikeness between two objects, what is our warrant? and what do we mean by the unlikeness, objectively considered? Our warrant is the persistence of force. Some kind or amount of change has been wrought in us by the one which has not been wrought by the other. This change we ascribe to some force exercised by the one which the other has not exercised. And we have no alternative but to do this, or to assert that the change had no antecedent, which is to deny the persistence of force. Whence it is further manifest that what we regard as the objective unlikeness is the presence in the one of some force, or set of forces, not present in the other — something in the kinds or amounts or directions of the constituent forces of the one, which those of the other do not parallel. But now if things or parts of things which we call different, are those of which the constituent forces differ in one or more respects, what must happen to any like forces, or any uniform force, falling on them? Such like forces, or parts of a uniform force, must be differently modified. The force which is present in the one and not in the other, must be an element in the conflict — must produce its equivalent reaction; and must so affect the total reaction. To say otherwise is to say that this differential force will produce no effect, which is to say that force is not persistent.

I need not develop this corollary further. It manifestly follows that a uniform force falling on a uniform aggregate, must undergo dispersion; that falling on an aggregate made up of unlike parts, it must undergo dispersion from each part, as well as qualitative differentiations; that in proportion as the parts are unlike, these qualitative differentiations must be marked; that in proportion to the number of the parts, they must be numerous; that the secondary forces so produced must undergo further transformations while working equivalent transformations in the parts that change them; and similarly with the forces they generate. Thus the conclusions that a part-cause of Evolution is the multiplication of effects, and that this increases in geometrical progression as the heterogeneity becomes greater, are not only to be established inductively, but are deducible from the deepest of all truths.

Chapter 21


§163. The general interpretation of Evolution is far from being completed in the preceding chapters. We must contemplate its changes under yet another aspect, before we can form a definite conception of the process constituted by them. Though the laws already set forth furnish a key to the re-arrangement of parts which Evolution exhibits, in so far as it is an advance from the uniform to the multiform, they furnish no key to this rearrangement in so far as it is an advance from the indefinite to the definite. On studying the actions and reactions everywhere going on, we have found it to follow from a certain primordial truth, that the homogeneous must lapse into the heterogeneous, and that the heterogeneous must become more heterogeneous; but we have not discovered why the differently-affected parts of any simple whole, become clearly marked off from one another, at the same time that they become unlike. Thus far no reason has been given why there should not ordinarily arise a vague chaotic heterogeneity, in place of that orderly heterogeneity displayed in Evolution. It still remains to find out the cause of that local integration which accompanied local differentiation — that gradually-completed segregation of like units into a group, distinctly separated from neighbouring groups which are severally made up of other kinds of units. The rationale will be conveniently introduced by a few instances in which we may watch this segregative process taking place.

When, late in September, the trees are gaining their autumn colours, and we are hoping soon to see a further change increasing the beauty of the landscape, we are sometimes disappointed by the occurrence of an equinoctial gale. Out of the mixed mass of foliage on each branch , the strong current of air carries away the decaying and brightly-tinted leaves, but fails to detach those which are still green. And while these last, frayed and seared by long-continued beatings against one another, give a sombre colour to the woods, the red and yellow and orange leaves are collected together in ditches and behind walls and in corners where eddies allow them to settle. That is to say , by that uniform force which the wind exerts on both kinds, the dying leaves are picked out from among their still-living companions and gathered in places by themselves. Again, the separation of particles of different sizes, as dust and sand from pebbles, may be similarly effected, as we see on every road in March. And from the days of Homer downwards, the power of currents of air, natural and artificial, to part from one another units of unlike characters, has been habitually utilized in the winnowing of chaff from wheat. In every brook we see how the mixed materials carried down are separately deposited — how in rapids the bottom gives rest to nothing but boulders and pebbles; how where the current is not so strong, sand is let fall; and how , in still places, there is a sediment of mud. This selective action of moving water is commonly applied in the arts to obtain masses of particles of different degrees of fineness. Emery, for example, after being ground, is carried by a slow current through successive compartments; in the first of which the largest grains subside; in the second of which the grains that settle before the water has escaped, are somewhat smaller; in the third smaller still; until in the last there are deposited those finest particles which have not previously been able to reach the bottom. And in a way that is different though equally significant, this segregative effect of water in motion, is exemplified in the carrying away of soluble from insoluble matters — an application of it hourly made in every laboratory. The effects of the uniform forces which aerial and aqueous currents exercise, are paralleled by those of uniform forces of other orders. Electric attraction will separate small bodies from large, or light bodies from heavy. By magnetism, grains of iron may be selected from other grains; as by the Sheffield grinder, whose magnetized gauze-mask filters out the steel-dust his wheel gives off , from the stone-dust which accompanies it. And how the affinity of any agent acting differently on the mixed components of a body, enables us to take away some component and leave the rest behind , is perpetually shown in chemical experiments.

What, now, is the general truth here variously presented? How are these facts, and countless similar ones, to be expressed in terms that embrace them all? In each case we see in action a force which may be regarded as simple or uniform-fluid motion in a certain direction at a certain velocity; electric or magnetic attraction of a given amount; chemical affinity of a particular kind; or rather, in strictness, the acting force is compounded of one of these with some other uniform force, as gravitation, etc. In each case we have an aggregate made up of unlike units — either atoms of different substances combined or intimately mingled, or fragments of the same substance of different sizes, or other constituent parts that are unlike in their specific gravities, shapes, or other attributes. And in each case these unlike units, or groups of units, of which the aggregate consists, are, under the influence of some resultant force acting indiscriminately on them all, separated from one another — segregated into minor aggregates, each consisting of units that are severally like one another and unlike those of the other minor aggregates. Such being the common aspect of these changes, let us look for the common interpretation of them.

In the chapter on "The Instability of the Homogeneous," it was shown that a uniform force falling on any aggregate, produces unlike modifications in its different parts — turns the uniform into the multiform and the multiform into the more multiform. The transformation thus wrought, consists of either insensible or sensible changes of relative position among the units, or of both. Such portion of the permanently effective force as reaches each different part, or differently-conditioned part, may be expended in modifying the mutual relations of its constituents; or it may be expended in moving the part to another place; or it may be expended partially in the first and partially in the second. And if little or none is absorbed in re-arranging the components of a compound unit, much or the whole must show itself in motion of such compound unit to some other place in the aggregate. and conversely. What must follow from this, in cases where none or only part of the force generates chemical re-distributions, what physical re-distributions must be generated? Parts that are similar to each other will be similarly acted on by the force, while parts that are dissimilar will be dissimilarly acted on. Hence the permanently effective incident force, when wholly or partially transformed into mechanical motion of the units, will produce like motions in units that are alike, and unlike motions in units that are unlike. If then, in an aggregate containing two or more orders of mixed units, those of the same order will be moved in the same way, and in a way that differs from that in which units of other orders are moved, the respective orders must segregate. A group of like things on which are impressed motions that are alike in amount and direction, must be transferred as a group to another place, and if they are mingled with some group of other things, on which the motions impressed are like one another, but unlike those of the first group in amount or direction or both, these other things must be transferred as a group to some other place — the mixed units must undergo a simultaneous selection and separation.

Further to elucidate this process, let me set down a few instances in which we may see that the definiteness of the separation is in proportion to the definiteness of the differences among the units. Take a handful of pounded substance, containing fragments of all sizes, and let it fall gradually while a gentle breeze is blowing. The large fragments will be collected on the ground almost immediately under the hand; somewhat smaller fragments will be carried a little to the leeward; still smaller ones further away; and those minute particles we call dust, will be drifted far before they reach the earth: that is, the segregation is indefinite where the differences among the fragments are indefinite, though the divergences are greatest where the differences are greatest. If, again, the handful be made up of distinct orders of units — as pebbles, coarse sand, and dust — these will, under like conditions, be segregated with greater definiteness. The pebbles will drop almost vertically; the sand, falling obliquely, will deposit itself within a tolerably circumscribed space beyond the pebbles; while the dust will be blown almost horizontally to a great distance. A case in which another kind of force comes into play, will still better illustrate this truth. Through a mixed aggregate of soluble and insoluble substances, let water slowly percolate. There will in the first place be a distinct parting of the substances that are the most widely unlike: the soluble will be carried away; the insoluble will remain behind. Further, some separation, though a less definite one, will be effected among the soluble substances; since the first part of the current will remove the most soluble in the largest amounts, and after these have been dissolved, it will continue to bring out the remaining less soluble. Even the undissolved matters will have simultaneously undergone some segregation; for the percolating fluid will carry down the minute fragments from among the large ones, and will often deposit those of small specific gravity in one place, and those of great specific gravity in another. To complete the elucidation we must glance at the obverse fact; namely that mixed units which differ but slightly, are moved in but slightly different ways by incident forces, and can therefore be separated only by such adjustments of the incident forces as allow slight differences to become appreciable factors in the result. The parting of alcohol from water by distillation is a good example. Here we have molecules consisting of oxygen and hydrogen, mingled with molecules consisting of oxygen, hydrogen, and carbon. The two orders of molecules have a considerable likeness of nature: they similarly maintain a fluid form at ordinary temperatures; they similarly become gaseous more and more rapidly as the temperature is raised; and they boil at points not very far apart. Now this comparative likeness of the molecules is accompanied by difficulty in segregating them. If the mixed fluid is unduly heated, much water distils over with the alcohol: it is only within a narrow range of temperature that molecules of the one kind are driven off rather than the others; and even then not a few of the others accompany them. The most interesting and instructive example, however, is furnished by certain phenomena of crystallization. When several salts that have little analogy of constitution, are dissolved in the same body of water, they are separated without much trouble, by crystallization: subject as they are to uniform forces, they segregate. The crystals of each salt do, indeed, usually contain certain small amounts of the other salts present in the solution; but from these they are severally freed by repeated re-solutions and crystallizations. Mark now, however, that the reverse is the case when the salts contained in the same body of water are chemically homologous. The nitrates of baryta and lead, or the sulphates of zinc, soda, and magnesia, unite in the same crystals; nor will they crystallize separately if these crystals be dissolved afresh, and afresh crystallized. On seeking the cause of this anomaly, chemists found that such salts were isomorphous-that their molecules, though not chemically identical, are identical in the proportions of acid, base, and water, composing them, and in the crystalline forms they assume when uniting. Here, then, we see clearly that units of unlike kinds are selected out and separated with a readiness proportionate to the degree of their unlikeness.

There is a converse cause of segregation which it is needless here to treat of with equal fullness. If different units acted on by the same force, must be differently moved; so, conversely units of the same kind must be differently moved by different forces. Supposing some group of units forming part of a homogeneous aggregate, are unitedly exposed to a force which is unlike in amount or direction to the force acting on the rest of the aggregate, then this group of units will separate from the rest, provided that, of the force so acting on it, there remains any portion not dissipated in molecular vibrations or absorbed in producing molecular rearrangements. After all that has been said above, this proposition needs no defence.

Before ending our preliminary exposition, a complementary truth must be specified; namely that mixed forces are segregated by the reaction of uniform matters, just as mixed matters are segregated by the action of uniform forces. Of this truth a complete and sufficient illustration is furnished by the dispersion of refracted light. A beam of light, made up of ethereal undulations of different orders, is not uniformly deflected by a homogeneous refracting body; but the different orders of undulations it contains are deflected at different angles: the result being that these different orders of undulations are separated and integrated, and so produce the colours of the spectrum. A segregation of another kind occurs when rays of light traverse an obstructing medium. Those which consist of comparatively short undulations are absorbed before those which consist of comparatively long ones; and the red rays, which consist of the longest undulations, alone penetrate when the obstruction is very great. How, conversely, there is produced a separation of like forces by the reaction of unlike matters, is also made manifest by the phenomena of refraction; since adjacent and parallel beams of light, falling on, and passing through, unlike substances, are made to diverge.

§164. In vague ways the heavenly bodies exemplify that cause of material segregation last assigned — the action of unlike forces on like units.

I say in vague ways because our Sidereal System displays more of aggregation than of segregation. That the irregular swarms of stars constituting the Milky Way with its branches and gaps and denser regions, have been gathered together from a more widely diffused state, may be reasonably inferred; though as we know nothing of the preceding distribution such a change cannot be proved: still less can there be proved a segregative process.

It is true that in clusters of stars, beginning with those having members considerably dispersed and ending with those having members closely concentrated-globular clusters — we see strong evidence of aggregation; and it may be contended that since the mutual gravitations of the stars forming a cluster, differ in their degrees and directions from those of the stars from which they have separated, there is a kind of segregation. But it must be admitted that the conformity to the above-named principle is but an indefinite one.

There are, however, two classes of facts which exhibit segregation, though they leave us ignorant of its causes. The first is that star-clusters are abundant along the course of the Milky Way: by far the larger number of them lying in the neighbourhood of its plane and relatively few in regions on either side. The second is that, contrariwise, the nebulae are sparsely scattered in and about the galactic circle and are relatively numerous in the spaces remote from it. Though there are thus presented two cases of segregation there is no evidence that these different classes of bodies have been separated from a mixed assemblage, nor is there any indication of the forces by which this contrast in distribution has been produced. We can only say that the facts are congruous with the belief that segregation, probably indirect rather than direct in its cause, has been going on.

The formation and detachment of a nebulous ring, illustrates the same general principle. To conclude, as Laplace did, that the equatorial portion of a rotating nebulous spheroid will, during concentration, acquire a centrifugal force sufficient to prevent it from following the rest of the contracting mass, is to conclude that such portions will remain behind as are in common subject to a certain differential force. The line of division between the ring and the spheroid, must be a line inside of which the aggregative force is greater than the force resisting aggregation; and outside of which the force resisting aggregation is greater than the aggregative force. Hence the alleged process conforms to the law that among like units, exposed to unlike forces, the similarly conditioned separate from the dissimilarly conditioned.

§165. Those geologic changes usually classed as aqueous, display under numerous forms the segregation of unlike units by a uniform incident force. On seashores the waves are ever sorting-out and separating the mixed materials against which they break. From each mass of fallen cliff, the tide carries away all those particles which are so small as to remain long suspended in the water; and, at some distance from shore, deposits them in the shape of fine sediment. Large particles, sinking with comparative rapidity, are accumulated into beds of sand near low water-mark. The small pebbles collect together at the bottom of the incline up which the breakers rush; and on the top lie the larger stones and boulders. Still more specific segregations may occasionally be observed. Flat pebbles, produced by the breaking down of laminated rock, are sometimes separately collected in one part of a shingle bank. On this shore the deposit is wholly of mud; on that it is wholly of sand. Here we find a sheltered cove filled with small pebbles almost of one size; and there, in a curved bay one end of which is more exposed than the other we see a progressive increase in the massiveness of the stones as we walk from the less exposed to the more exposed end. Trace the history of each geologic deposit, and we are quickly led down to the fact that mixed fragments of matter, differing in their sizes or weights, are, when exposed to the momentum and friction of water, joined with the attraction of the Earth, selected from one another, and united into groups of comparatively like fragments. And we see that, other things equal, the separation is definite in proportion as the differences of the units are marked. After they have been formed, sedimentary strata exhibit segregations of another kind. The flints and the nodules of iron pyrites that are found in chalk, as well as the silicious concretions which sometimes occur in limestone, are interpreted as aggregations of molecules of silex or sulphuret of iron, originally diffused through the deposit, but gradually collected round centres, notwithstanding the solid or semi-solid state of the surrounding matter. Bog iron-ore supplies the conditions and the result in still more obvious correlation.

Among igneous changes we do not find so many examples of the process described. Nevertheless, geological phenomena of this order are not barren of illustrations. Where the mixed matters composing the Earth's crust have been raised to a very high temperature, segregation commonly takes place as the temperature falls. Sundry of the substances that escape in a gaseous form from volcanoes, sublime into crystals on coming against cool surfaces; and solidifying, as these substances do, at different temperatures, they are deposited at different parts of the crevices through which they are emitted together. The best illustration, however, is furnished by the changes that occur during the slow cooling of igneous rock. When, through one of the fractures from time to time made in the Earth's crust, a portion of the molten nucleus is extruded, and when this is cooled with comparative rapidity, there results trap or basalt — a substance that is uniform in texture, though made up of various ingredients. But when, not escaping through the superficial strata, such a portion of the molten nucleus is slowly cooled, granite is the result: the mingled particles of quartz, feldspar, and mica, being kept for a long time in a fluid and semi-fluid state — a state of comparative mobility-undergo those changes of position which the forces impressed on them by their fellow units necessitate. The differential forces arising from mutual polarity, segregate the quartz, feldspar, and mica, into crystals. How completely this is dependent on the long-continued agitation of the mixed particles, and consequent long-continued movableness by small differential forces, is proved by the fact that in a granite dyke the crystals in the centre, where the fluidity or semi-fluidity continued for a longer time, are much larger than those at the sides, where contact with the neighbouring rock caused more rapid cooling and solidification.

§166. The actions going on throughout an organism are so involved, that we cannot expect to identify the forces by which particular segregations are effected. Among the few instances admitting. of interpretation, the best are those in which mechanical pressures and tensions are the agencies at work.

The spine of a vertebrate animal is subjected to certain general strains — the weight of the body, together with the reactions involved by all considerable muscular efforts; and under these conditions it has become segregated as a whole. At the same time being exposed to different forces during those lateral bendings which the movements necessitate, its parts retain a certain separateness. If we trace up the development of the vertebral column from its primitive form of a cartilaginous cord in the lowest fishes, we see that, throughout, it maintains an integration corresponding to the unity of the incident forces, joined with a division into segments corresponding to the variety of the incident forces. Each segment, considered apart, exemplifies the truth more simply. A vertebra is not a single bone, but consists of a central mass with sundry appendages or processes, and in unfinished types of vertebra these appendages are separate from the central mass, and, indeed, exist before it makes its appearance. But these several independent bones constituting a primitive spinal segment, are subjected to a certain aggregate of forces which agree more than they differ: as the fulcrum to a group of muscles habitually acting together, they perpetually undergo certain reactions in common. And accordingly, in the course of development, they gradually coalesce. Still clearer is the illustration furnished by spinal segments that become fused together where they are together exposed to some predominant strain. The sacrum consists of a group of vertebra firmly united. In the ostrich and its congeners there are from seventeen to twenty sacral vertebra; and, besides being confluent with one another , these are confluent with the iliac bones, which run on each side of them. If, now , we assume these vertebra to have been originally separate, as they still are in the embryo bird, and if we consider the forces to which they must in such case have been exposed, we shall see that their union results in the alleged way. For through these vertebra the entire weight of the body is transferred to the legs: the legs support the pelvic arch; the pelvic arch supports the sacrum; and to the sacrum is articulated the rest of the spine, with all the organs attached to it and upheld by it. Hence, if separate, the sacral vertebra must be held firmly together by strongly-contracted muscles, and must, by implication, be prevented from partaking in those lateral movements which the other vertebra undergo — they must be subjected to a common strain, while they are preserved from strains which would affect them differently; and so they fulfil the conditions under which segregation occurs. But the cases in which cause and effect are brought into the most obvious relation, are supplied by the limbs. The metacarpal bones (those which in man support the palm of the hand) are separate from one another in most mammals: the separate actions of the toes entailing on them slight amounts of separate movements. This is not so however in the ox-tribe and the horse-tribe. In the ox-tribe, only the middle metacarpals (third and fourth) are developed; and these, attaining massive proportions, coalesce to form the cannon bone. In the horse-tribe, the segregation is what we may distinguish as indirect: the second and fourth metacarpals are present only as rudiments united to the sides of the third, while the third is immensely developed; thus forming a cannon bone which differs from that of the ox in being a single cylinder, instead of two cylinders fused together. The metatarsus in these quadrupeds exhibits parallel changes. Now each of these metamorphoses occurs where the different bones grouped together have no longer any different functions, but retain only a common function. The feet of oxen and horses are used solely for locomotion — are not put, like those of unguiculate mammals, to purposes which involve some relative movements of the metacarpals. Thus there directly or indirectly results a single mass of bone where the incident force is single. And for the inference that these facts have a causal connexion, we find confirmation throughout the entire class of birds, in the wings and legs of which, like segregations are found under like conditions. While this sheet is passing through the press (1862), a fact illustrating this general truth in a yet more remarkable manner, has been mentioned to me by Prof. Huxley who kindly allows me to make use of it while still unpublished by him. The Glyptodon, an extinct mammal found fossilized in South America, has long been known as a large uncouth creature allied to the Armadillo, but having a massive dermal armour consisting of polygonal plates closely fitted together so as to make a vast box, inclosing the body in such way as effectually to prevent it from being bent, laterally or vertically, in the slightest degree. This box, which must have weighed several hundredweight, was supported on the spinous processes of the vertebrae, and on the adjacent bones of the pelvic and thoracic arches. And the significant fact is that here, where the trunk vertebrae were together exposed to the pressure of this heavy dermal armour, at the same time that, by its rigidity , they were preserved from all relative movements, they were united into one solid, continuous bone.

The formation and maintenance of a species, considered as an assemblage of similar organisms, is interpretable in an analogous way. Already we have seen that in so far as the members of a species are subject to different sets of incident forces, they are differentiated, or divided into varieties. Here it remains to add that such of them as are subject to like sets of incident forces, are segregated. For by the process of "natural selection," there is a continual purification of each species from those individuals which depart from the common type in ways that unfit them for the conditions of their existence. Consequently, there is a continual leaving behind of those individuals which are in all respects fit for the conditions of their existence, and are therefore nearly alike. The circumstances to which any species is exposed, being an involved combination of incident forces; and the members of the species having among them some that differ more than is usual from the average structure required for meeting these forces; it results that these forces are constantly separating such divergent individuals from the rest, and so preserving the uniformity of the rest — keeping up its integrity as a species or variety. Just as the changing autumn leaves are picked out by the wind from among the green ones around them, or just as, to use Prof. Huxley's simile, the smaller fragments pass through a sieve while the larger are kept back; so, the uniform incidence of external forces affects the members of a group of organisms similarly in proportion as they are similar, and differently in proportion as they are different; and thus is ever segregating the like by parting the unlike from them. Whether these separated members are killed off, as mostly happens, or whether, as otherwise happens, they survive and multiply into a distinct variety, in consequence of their fitness to certain partially-unlike conditions, matters not to the argument. The one case conforms to the law that the unlike units of an aggregate are sorted into their kinds and parted, when uniformly subject to the same incident forces, and the other to the converse law that the like units of an aggregate are parted and separately grouped when subject to different incident forces. And on consulting Mr. Darwin's remarks on divergence of character, it will be seen that the segregations thus caused tend ever to become more definite.

§167. Mental evolution under one of its leading aspects, we found to consist in the formation in the mind of groups of like objects and like relations — a differentiation of the various things originally confounded together in one assemblage, and an integration of each separate order of things into a separate group (§153). Here it remains to point out that while unlikeness in the incident forces is the cause of such differentiations, likeness in the incident forces is the cause of such integrations. For what is the process through which classifications are established? How do plants become grouped in the mind of the botanist into orders, genera, and species? Each plant he examines yields him a certain complex impression. Now and then he picks up a plant like one before seen; and the recognition of it is the production in him of a like connected group of sensations, by a like connected group of attributes. That is to say there is produced throughout the nerve-centres concerned, a combined set of changes, similar to a combined set of changes before produced. Considered analytically, each such combined set of changes is a combined set of molecular modifications wrought in the affected part of the organism. On every repetition of the impression, a like combined set of molecular modifications is superposed on the previous ones, and makes them greater: thus generating an internal plexus of.modifications, with its answering idea, corresponding to these similar external objects. Meanwhile, another kind of plant produces in the brain of the botanist another set of molecular modifications — a set which does not agree with the one we have been considering, but disagrees with it; and by repetition of such there is generated a different idea answering to a different species. What, now, is the nature of this process expressed in general terms? On the one hand there are the like and unlike things from which severity emanate the groups of forces by which we perceive them. On the other hand, there are the organs of sense and percipient centres, through which, in the course of observation, these groups of forces pass. In passing through them the like groups of forces are segregated, or separated from the unlike groups of forces; and each such separate series of groups of forces, answering to an external genus or species, produces an idea of the genus or species. We before saw that as well as a separation of mixed matters by the same force, there is a separation of mixed forces by the same matter; and here we may further see that the unlike forces so separated, work unlike structural changes in the aggregate that separates them — structural changes each of which thus represents the integrated series of motions that has produced it.

By a parallel process, the relations of co-existence and sequence among impressions, become sorted into kinds and grouped. When two phenomena that have been experienced in a given order, are repeated in the same order, those nerve-centres which before were affected by the transition are again affected; and such molecular modification as they received from the first motion propagated through them is increased by this second motion. Each such motion works a structural alteration which, in conformity with the law set forth in Chapter IX, involves a diminished resistance to all such motions that afterwards occur. The segregation of these successive motions (or more strictly, the permanently effective portions of expanded them in overcoming resistance) thus becomes the cause of, and the measure of, the mental connexions between the impressions which the phenomena produced. Meanwhile, phenomena different from these, being phenomena that affect different nervous elements, will have their connexions severally represented by motions along other routes; and along each of these other routes, the nervous discharges will severally take place with a readiness proportionate to the frequency with which experience repeats the connexions of phenomena. The classification of relations must hence go on pari passu with the classification of the related things. In common with the mixed sensations received from the external world, the mixed relations it presents cannot be impressed on the organism.without more or less segregation of them resulting. And through this continuous sorting and grouping of changes or motions, which constitutes nervous function, there is gradually wrought that sorting and grouping of matter, which constitutes nervous structure.

§168. In social evolution, the collecting together of the like and the separation of the unlike by incident forces, is primarily displayed in the same manner as we saw it to be among groups of inferior creatures. The human races tend to differentiate and integrate, as do races of other living forms.

Of the forces which effect and maintain the segregations of mankind, may first be named those external ones classed as physical conditions. The climate and food which are favourable to an indigenous people, are more or less detrimental to an alien people of different bodily constitution. In tropical regions the northern races cannot permanently exist: if not killed off in the first generation, they are so in the second, and, as in India, can maintain their footing only by the artificial process of continuous immigration and emigration. That is to say, the external forces acting equally on the inhabitants of a given locality, tend to expel all who are not of a certain type, and thus to keep up the integration of those who are of that type. Even among the Indian peoples themselves the like happens: some of the hill-tribes being segregated by surviving the malarious influences which kill off Hindus who enter their habitat. The other foxes conspiring to produce these national segregations, are those mental ones shown in the affinities of men for others like themselves. Units of one society who are obliged to reside in another, generally form colonies in the midst of that other — small societies of their own. Races which have been artificially severed, show tendencies to re-unite. Now though these segregations caused by the mutual likings of kindred men, do not seem due to the general principle enunciated, they really are thus interpretable. When treating of the direction of motion (§80), it was shown that the actions performed by men for the satisfaction of their wants, are always motions along lines of least resistance. The feelings characterizing a member of a given race, are feelings which get complete satisfaction only among other members of that race a satisfaction partly derived from sympathy with those having like feelings, but mainly derived from the adapted social conditions which grow up where such feelings prevail. When, therefore, a citizen of any nation is, as we see, attracted towards others of his nation, the rationale is that certain agencies which we call desires, move him in the direction of least resistance. Human motions, like all other motions, being determined by the distribution of forces, it follows that such segregations of races as are not produced by incident external forces, are produced by forces which the units of the races exercise on one another.

During the development of each society we see analogous segregations caused in analogous ways. A few of them result from minor natural affinities; but those most important ones which constitute political and industrial organization, result from the union of men in whom similarities have been produced by training. Men brought up to bodily labour are men who have had wrought in them a certain likeness — a likeness which, in respect of their powers of action, obscures and subordinates their natural differences. Those trained to brain-work have acquired a certain other community of character which makes them, as social units, more like one another than like those trained to manual occupations. And there arise class-segregations answering to these super-induced likenesses. More definite segregations take place among the more definitely assimilated members of any class who are brought up to the same calling. Even where the necessities of their work forbid concentration in one locality, as among artizans happens with masons and bricklayers, and among traders happens with the retail distributers, and among professionals happens with the medical men, there are not wanting Operative Builders' Unions, and Grocers' Societies, and Medical Associations, implying a process of sifting out and grouping. And where, as among the manufacturing classes, the functions discharged do not require the dispersion of citizens who are artificially assimilated, there is an aggregation of them in special localities, and a consequent increase in the definiteness of industrial divisions. If, now, we seek the causes of these segregations, considered as results of force and motion, we are brought to the same general principle as before. This likeness produced in the members of any class or sub-class by training, is an aptitude acquired by them for satisfying their wants in like ways. That is, the occupation has become to each a line of least resistance. Hence under that pressure which determines all men to activity these similarly — modified social units are similarly affected, and tend to take similar courses. If, then, there be any locality which, either by its physical peculiarities or by peculiarities wrought on it during social evolution, is rendered a place where a certain kind of industrial action meets with less resistance than elsewhere, it follows from the law of direction of motion that those social units who have been moulded to this kind of industrial action, will be segregated by moving towards this place. If, for instance, the proximity of coal and iron mines to a navigable river, gives to Glasgow an advantage in the building of iron-ships-if the total labour required to produce a given vessel, and get its equivalent in food and clothing, is less there than elsewhere; there is caused a concentration of iron-ship builders at Glasgow, either by detention of the population born to iron-ship building, or by immigration of those elsewhere engaged in it, or by both. The principle equally holds where the occupation is mercantile instead of manufacturing. Stock-brokers cluster where the amount of effort to be severally gone through by them in discharging their functions, and obtaining their profits, is less than elsewhere. A local exchange having once been established, becomes a place where the resistance to be overcome by each is smaller than in any other place; and, being like units under stress of common desires, pursuit of the course of least resistance by each involves their aggregation around this place.

Of course, with units so complex as those which constitute a society , and with forces so involved as those which move them, the resulting selections and separations must be far more entangled, or far less definite, than those we have hitherto considered. For men's likenesses being of various kinds, lead to various orders of segregation. There are likenesses of disposition, likenesses of taste, likenesses produced by education, likenesses that result from class-habits, likenesses of political feeling; and it needs but to glance round at the caste-divisions, the associations for philanthropic, scientific, and artistic purposes, the religious parties and social cliques, to see that some species of likeness among the component members of each body determines their union. Now the different segregative processes, by traversing one another and often by their indirect antagonism, more or less obscure one another's effects, and prevent any one differentiated class from completely integrating. But if this cause of incompleteness be borne in mind, social segregations will be seen to conform to the same principle as all other segregations.

§169. Can the general truth thus variously illustrated be deduced from the persistence of forte, in common with foregoing truths? Probably the exposition at the beginning of the chapter will have led most readers to conclude that it can be so deduced.

The abstract propositions involved are these: — First, that like units, subject to a uniform force capable of producing motions in them, will be moved to like degrees in the same direction. Second, that like units if exposed to unlike forces capable of producing motion in them, will be differently moved-moved either in different directions or to different degrees in the Same direction. Third, that unlike units if acted on by a uniform force capable of producing motion in them, will be differently moved — moved either in different directions or to different degrees in the same direction. Fourth, that the incident forces themselves must be affected in analogous ways: like forces falling on like units must be similarly modified by the conflict; unlike forces falling on like units must be dissimilarly modified; and like forces falling on unlike units must be dissimilarly modified. These propositions may be reduced to a still more abstract form. They all imply that in the actions and reactions of force and matter, an unlikeness in either of the factors necessitates an unlikeness in the effects, and that in the absence of unlikeness in either of the factors the effects must be alike.

When they are thus generalized, the dependence of these propositions on the persistence of force is obvious. Any two forces that are not alike, are forces which differ either in their amounts or directions or both; and by what is called the resolution of forces, it may be proved that this difference is constituted by the presence in the one of some force not present in the other. Similarly, any two units or portions of matter which are unlike in size, form, weight, or other attribute, can be known as unlike only through some unlikeness in the forces they impress on us; and hence this unlikeness also, is constituted by the presence in the one of some force or forces not present in the other. Such being the common nature of these unlikenesses, what is the corollary? Any unlikeness in the incident forces, where the things acted on are alike, must generate a difference between the effects; since, otherwise, the differential force produces no effect, and force is not persistent. Any unlikeness in the things acted on, where the incident forces are alike, must generate a difference between the effects; since, otherwise, the differential force whereby these things are made unlike, produces no effect, and force is not persistent. While, conversely, if the forces acting and the things acted on are alike, the effects must be alike; since, otherwise, a differential effect can be produced without a differential cause, and force is not persistent.

Thus these general truths being necessary implications. of the persistence of force, all the re-distributions above traced out as characterizing Evolution in its various phases, are also implications of the persistence of force. If of the mixed units making up any aggregate, those of the same kind have like motions impressed on them by a uniform force, while units of another kind are moved by this uniform force in ways more or less unlike the ways in which those of the first kind are moved, the two kinds must separate and integrate. If the units are alike and the forces unlike, a division of the differently affected units is equally necessitated. Thus there inevitably arises the demarcated grouping which we everywhere see. By virtue of this segregation, growing ever more decided while there remains any possibility of increasing it, the change from uniformity to multiformity is accompanied by a change from indistinctness in the relations of parts to distinctness in the relations of parts. As we before saw that the transformation of the homogeneous into the heterogeneous is inferable from that ultimate truth which transcends proof; so we here see that from this same truth is inferable the transformation of an indefinite homogeneity into a definite heterogeneity.

Chapter 22


§170. towards what do these changes tend? Will they go on for ever? or will there be an end to them? Can things increase in heterogeneity through all future time? or must there be a degree which the differentiation and integration of Matter and Motion cannot pass? Is it possible for this universal metamorphosis to proceed in the same general course indefinitely? or does it work towards some ultimate state admitting no further modification of like kind? The last of these alternative conclusions is that to which we are inevitably driven. Whether we watch concrete processes, or whether we consider the question in the abstract, we are alike taught that Evolution has an impassable limit.

The re-distributions of matter which go on around us, are ever being brought to conclusions by the dissipation of the motions which effect them. The rolling stone parts with portions of its momentum to the things it strikes, and finally comes to rest; as do also, in like manner, the various things it has struck. Descending from the clouds and trickling over the Earth's surface till it gathers into brooks and rivers, water, still running towards a lower level, is at last arrested by the resistance of other water that has reached the lowest level. In the lake or sea thus formed, every agitation raised by a wind or the immersion of a solid body, propagates itself around in waves which diminish as they widen, and gradually become lost to observation in motions communicated to the atmosphere and the matter on the shores. The impulse given by a player to a harp-string is transformed through its vibrations into aerial pulses; and these, spreading on all sides, and weakening as they spread, soon cease to be perceptible, and are gradually expended in generating thermal undulations that radiate into space: each aerial pulse causing compression and evolution of heat. Equally in the cinder which falls out of the fire, and in the vast mass of molten lava ejected by a volcano, we see that the molecular agitation disperses itself by radiation; so that the temperature inevitably sinks at last to the same degree as that of surrounding bodies. The proximate rationale of the process exhibited under these several forms, lies in the fact dwelt on when treating of the Multiplication of Effects, that motions are ever being decomposed into divergent motions, and these into re-divergent motions. The rolling stone sends off the stones it hits in directions differing more or less from its own, and they do the like with the things they hit. Move water or air, and the movement is quickly resolved into dispersed movements. The heat produced by pressure in a given direction diffuses itself by undulations in all directions. That is to say, these motions undergo division and subdivision, and by continuance of this process without limit they are, though never lost, gradually dissipated.

In all cases, then, there is a progress toward equilibrium. That universal co-existence of antagonist forces which, as we before saw, necessitates the universality of rhythm, and which, as we before saw, necessitates the decomposition of every force into divergent forces, at the same time necessitates the ultimate establishment of a balance. Every motion, being motion under resistance, is continually suffering deductions; and these unceasing deductions finally result in the cessation of the motion.

The general truth thus frustrated under its simplest aspect, we must now look at under those more complex aspects it usually presents throughout Nature. In nearly all cases, the motion of an aggregate is compound; and the equilibration of each of its components, being carried on independently, does not affect the rest. The ship's bell that has ceased to vibrate, still continues those vertical and lateral oscillations caused by the ocean-swell. The water of a smooth stream on whose surface have died away the undulations caused by a rising fish, moves as fast as before towards the sea. The arrested bullet travels with undiminished speed round the Earth's axis. And were the rotation of the Earth destroyed, there would not be implied any diminution of the Earth's movement with respect to the Sun and other external bodies. So that in every case, what we regard as equilibration is a disappearance of some one or more of the many movements a body possesses, while its other movements continue as before. That this process may be duly realized and the state of things towards which it tends fully understood, it will be well here to cite a case in which we may watch this successive equilibration of combined movements more completely than we can do in those above instanced. Our end will best be served not by the most imposing but by the most familiar example. Let us take that of a spinning top. When the string which has been wrapped round a top's axis is violently drawn off, and the top falls on to the table, it usually happens that besides the rapid rotation two other movements are given to it. A slight horizontal momentum, unavoidably impressed on it when leaving the handle, carries it. away bodily from the place on which it drops; and in consequence of its axis being more or less inclined, it falls into a certain oscillation, described by the expressive though inelegant word "wabbling." These two subordinate motions, variable in their proportions to each other and to the chief motion, are commonly soon brought to a close by separate processes of equilibrium. The momentum which carries the top bodily along the table, resisted somewhat by the air but mainly by the irregularities of the surface, shortly disappears; and the top thereafter continues to spin on one spot. Meanwhile, in consequence of that opposition which the axial momentum of a rotating body makes to any change in the plane of rotation, (so beautifully exhibited by the gyroscope,) the "wabbling" diminishes, and like the other is quickly ended. These minor motions having been dissipated, the rotatory motion, interfered with only by atmospheric resistance and the friction of the pivot, continues some time with such uniformity that the top appears stationary: there being thus temporary established a condition which the French mathematicians have termed equilibrium mobile. It is true that when the velocity of rotation sinks below a certain point, new motions commence and increase till the top falls; but these are merely incidental to a case in which the centre of gravity is above the point of support. Were the top, having an axis of steel, to be suspended from a surface adequately magnetized, the moving equilibrium would continue until the top became motionless, without any further change of attitude. Now the facts which it behoves us here to observe are these. First, that the various motions which an aggregate possesses are separately equilibrated: those which are smallest, or which meet with the greatest resistance, or both, disappearing first; and leaving at last that which is greatest, or meets with least resistance, or both. Second, that when the aggregate has a movement of its parts with respect to each other which encounters but little external resistance, there is apt to be established a moving equilibrium. Third, that this moving equilibrium eventually lapses into complete equilibrium.

Fully to comprehend the process of equilibration, is not easy; since we have simultaneously to contemplate various phases of it. The best course will be to glance separately at what we may conveniently regard as its four different orders. The first order includes the comparatively simple motions, as those of projectiles, which are not prolonged enough to exhibit their rhythmical character, but which, being quickly divided and subdivided into motions communicated to other portions of matter, are presently dissipated in the rhythm of ethereal undulations. In the second order, comprehending various kinds of ordinary vibration or oscillation, the implied energy is used up in generating a tension which, having become equal to it or momentarily equilibrated with it, thereupon produces a motion in the opposite direction, that is subsequently equilibrated in like manner: thus causing a visible rhythm which is presently lost in invisible rhythms. The third order of equilibration, not hitherto noticed, obtains in those aggregates which continually receive as much energy as they expend. The steam-engine (and especially that kind which feeds its own furnace and boiler) supplies an example. Here the energy from moment to moment dissipated in overcoming the resistance of the machinery driven, is from moment to moment re-placed from the fuel; and the balance of the two is maintained by a raising or lowering of the expenditure according to the variation of the supply: each increase or decrease in the quantity of steam, resulting in a rise or fall of the engine's movement, such as brings it to a balance with the increased or decreased resistance. This, which we may fitly call the dependent moving equilibrium, should be specify noted; since it is one that we shall commonly meet with throughout various phases of Evolution. The equilibrium to be distinguished as of the fourth order, is the independent or perfect moving equilibrium. This we see illustrated in the rhythmical motions of the Solar System, which, being resisted only by a medium of inappreciable density, undergo no sensible diminution in such periods of time as we can measure.

Something has still to be added. The reader must note two leading truths brought out by the foregoing exposition: the one concerning the ultimate, or rather the penultimate, state of motion which the processes described tend to bring about; the other concerning the concomitant distribution of matter. This penultimate state of motion is the moving equilibrium, which tends to arise in an aggregate having compound motions, as a transitional state on the way towards complete equilibrium. Throughout Evolution of all kinds there is a continual approximation to, and more or less complete maintenance of, this moving equilibrium. As in the Solar System there has been established an independent moving equilibrium — an equilibrium such that the relative motions of its members are continually so counterbalanced by opposite motions, that the mean state of the aggregate never varies; so is it, though in a less distinct manner, with each form of dependent moving equilibrium. The state of things exhibited in the cycles of terrestrial changes, in the balanced functions of organic bodies that have reached their adult forms, and in the acting and re-acting processes of fully-developed societies, is similarly one characterized by compensating oscillations. The involved combination of rhythms seen in each of these cases, has an average condition which remains practically constant during the deviations ever taking place on opposite sides of it. And the fact which we have here to observe is that, as a corollary from the general law of equilibrium, every evolving aggregate must go on changing until a moving equilibrium is established; since, as we have seen, an excess of force which the aggregate possesses in any direction, must eventually be expended in overcoming resistances to change in that direction: leaving behind only those movements which compensate one another, and so form a moving equilibrium. Respecting the structural state simultaneously reached, it must obviously be one presenting an arrangement of forces that counterbalance all the forces to which the aggregate is subject. So long as there remains a residual force in any direction — be it excess of a force exercised by the aggregate on its environment, or of a force exercised by its environment on the aggregate, equilibrium does not exist; and therefore the re-distribution of matter must continue. Whence it follows that the limit of heterogeneity towards which every aggregate progresses, is the formation of as many specializations and combinations of parts, as there are specialized and combined forces to be met.

§171. Those successively changed forms which, if the nebular hypothesis be granted, must have arisen during the evolution of the Solar System, were so many transitional kinds of moving equilibrium, severally giving place to more enduring kinds. Thus the assumption of an oblate spheroidal figure by condensing nebulous matter, was the assumption of a temporary and partial moving equilibrium among the component parts — a moving equilibrium that must have grown more settled as local conflicting movements were dissipated. In the formation and detachment of the nebulous rings which, according to this hypothesis, from time to time took place, we have instances of progressive equilibration severally ending in the establishment of a complete moving equilibrium. For the genesis of each such ring implies a balancing of that attractive force which the whole spheroid exercises on its equatorial portion, by that centrifugal force which the equatorial portion has acquired during previous concentration. So long as these two forces are not equal, the equatorial portion follows the contracting mass; but as soon as the second force has increased up to an equality with the first, the equatorial portion can follow no further and remains behind. While, however, the resulting ring, regarded as a whole, has reached a state of moving equilibrium, its parts are not balanced with respect to one another. As we before saw (§150) the probabilities against the maintenance of an annular form by nebulous matter are great: from the instability of the homogeneous, it is inferable that nebulous matter so distributed will break up into portions, and eventually concentrate into a single mass. That is to say, the ring will progress towards a moving equilibrium of a more complete kind, during the dissipation of that motion which maintained its particles in a diffused form; leaving at length a planetary body attended perhaps by a group of minor bodies similarly produced, constituting a moving equilibrium that is all but perfect.*

<* Sir David Brewster has cited with approval, a calculation by M. Babinet, to the effect that on the hypothesis of nebular genesis, the matter of the Sun, when it filled the Earth's orbit, must have taken 3181 years to rotate; and that therefore the hypothesis cannot be true. This calculation of M. Babinet may pair-off with that of M. Comte who, contrariwise, made the time of this rotation agree very nearly with the Earth's period of revolution round the Sun. For if M. Comte's calculation involved a petitio principii, that of M. Babinet is based on two assumptions both of which are gratuitous, and one of them inconsistent with the doctrine to be tested. He has evidently proceeded on the current supposition respecting the Sun's internal density, which is not proved, and from which there are reasons for dissenting; and he has evidently taken for granted that all parts of the nebulous spheroid, when it filled the Earth's orbit, has the same angular velocity; whereas if (as is implied in the nebular hypothesis, rationally understood) this spheroid resulted from the concentration of widely-diffused matter, the angular velocity of its equatorial portion would obviously be far greater than that of its central portion.>

Hypothesis aside, the principle of equilibration is still perpetually illustrated in those minor changes of state which the Solar System undergoes. Each planet, satellite, and comet, exhibits at its aphelion a momentary equilibrium between that force which urges it further away from its primary, and that force which retards its retreat. In like manner at perihelion a converse equilibrium is momentarily established. The variation of each orbit in eccentricity, and in the position of its plane, has similarly a limit at which the forces producing change in the one direction, are equalled by those antagonizing it; and an opposite limit at which an opposite arrest takes place. Meanwhile, each of these simple perturbations, as well as each of the complex ones resulting from their combination, exhibits, besides the temporary equilibration at each of its extremes, a certain general equilibration of compensating deviations on either side of a mean state. That the moving equilibrium thus constituted tends, in the course of indefinite time, to lapse into a complete equilibrium, by the gradual decrease of planetary motions and eventual integration of all the separate masses composing the Solar System, is a belief suggested by certain observed cometary retardations — a belief entertained by some of high authority. The received option that the appreciable diminution in the period of Encke's comet, implies a loss of momentum caused by resistance to the ethereal medium, commits astronomers who hold it, to the conclusion that this same resistance must cause a loss of planetary motions — a loss which, infinitesimal though it may be in such periods as we can measure, will, if indefinitely continued, bring these motions to a close. Even should there be, as Sir John Herschel suggests, a rotation of the ethereal medium in the same direction with the planets, this arrest, though immensely postponed, would not be absolutely prevented. Such an eventuality, however, must in any case be so inconceivably remote as to have no other than a speculative interest for us. It is referred to here, simply as illustrating the still-continued tendency towards complete equilibrium, through the still-continued dissipation of sensible motion, or transformation of it into insensible motion.

But there is another species of equilibration going on in the Solar System, with which the human race is less remotely concerned. The tacit assumption that the Sun can continue to give off an undiminished amount of light and heat through all future time, is now abandoned. Involving as it does, under a disguise, the conception of power produced out of nothing, it is of the same order as the belief which misleads perpetual-motion schemers. The spreading recognition of the truth that whatever force is manifested under one shape must previously have existed under another shape, implies recognition of the truth that the force known to us in solar radiations, is the changed form of some other force of which the Sun is the seat; and that, by the emission of these radiations, this other force is being slowly exhausted. The force by which the Sun's substance is drawn to his centre of gravity, is the only one which physical laws warrant us in concluding to be the correlate of the forces emanating from him: the only assignable source for the insensible motions constituting solar light and heat, is the sensible motion which disappears during the concentration of the Sun's mass. We before saw it to be a corollary from the nebular hypothesis, that there is such a progressing concentration of the Sun's mass. And here remains to be added the further corollary, that just as in the case of the small members of the Solar System, the heat generated by concentration, once escaping rapidly, has in each left a central residue which escapes but slowly; so in the case of that immensely larger mass forming the Sun, the immensely greater quantity of heat generated and still in process of rapid diffusion, must, as the concentration approaches its limit, diminish in amount, and eventually leave but a relatively small internal remnant. With or without the accompaniment of that hypothesis of nebular condensation whence it naturally follows, the doctrine that the Sun is gradually losing his heat, has now gained general acceptance; and calculations have been made, both respecting the amount of heat and light already radiated, as compared with the amount that remains, and respecting the period during which active radiation will continue. Prof. Helmholtz estimates that since the time when, according to the nebular hypothesis, the matter composing the Solar System extended to the Orbit of Neptune, there has been evolved by the arrest of sensible motion, an amount of heat 454 times as great as that which the Sun still has to give out. He also makes an approximate estimate of the rate at which this remaining 1/464th is being diffused: showing that decrease of the Sun's diameter to the extent of 1/10,000 would produce heat, at the present rate, for more than 2000 years; or in other words, that a contraction of 1/20,000,000 of his diameter, suffices to generate the light and heat annually emitted; and that thus at the present rate of expenditure, the Sun's diameter will diminish by something like 1/20 in the lapse of the next million years.* Of course these conclusions are but rude approximations to the truth. Until quite recently, we have been totally ignorant of the Sun's chemical composition, and even now have obtained but a superficial knowledge of it. We know nothing of his internal structure; and it is quite possible that the assumptions respecting central density, made in the foregoing estimates, are wrong.

<* See paper "On the Inter-action of Natural Forces," by Prof. Helmholtz, translated by Prof. Tyndall, and published in the Philosophical Magazine, supplement to Vol. XI, in the fourth series.>

But no uncertainty in the data on which these calculations proceed, and no consequent error in the inferred rate at which the Sun is expending his reserve energy, militates against the general proposition that this reserve of energy is being expended, and must in time be exhausted.

Thus while the Solar System, if evolved from diffused matter, has illustrated the law of equilibration in the establishment of a moving equilibrium; and while, as at present constituted, it illustrates the law of equilibration in the perpetual balancing of all its movements; it also illustrates this law in these processes which astronomers and physicists infer are still going on. That motion of masses produced during Evolution, is being slowly rediffused in molecular motion of the ethereal medium; both through the progressive integration of each mass, and the resistance to its motion through space. Infinitely remote as may be the state when all the relative motions of its masses shall be transformed into molecular motion, and all the molecular motion dissipated; yet such a state of complete integration and complete equilibration, is that towards which the changes now going on throughout the Solar System inevitably tend.

§172. A spherical figure is the one which can alone equilibrate the forces of mutually-gravitating molecules. If an aggregate of such molecules rotates, the form of equilibrium becomes a spheroid of greater or less oblateness, according to the rate of rotation; and it has been ascertained that the Earth is an oblate spheroid, diverging just as much from sphericity as is requisite to counterbalance the centrifugal force consequent on its velocity round its axis. That is to say, during the evolution of the Earth, there has been reached an equilibrium of those forces which affect its general outline. The only other equilibration which the Earth as a whole can exhibit, is the loss of its rotation; and that any such loss is going on we have no direct evidence. It has been contended, however, by Prof. Helmholtz and others, that inappreciable as may be its effect within known periods of time, the friction of the tidal wave must be diminishing the Earth's motion round its axis, and must eventually destroy it. Now though it seems an oversight to say that the axial motion can thus be destroyed, since the extreme effect, to be reached only in infinite time, would be an extension of the Earth's day to the length of lunation; yet it seems clear that this friction of the tidal wave is a real cause of decreasing rotation. Slow as its action is, we must recognize its retarding effect as exemplifying, under another form, the universal progress towards equilibrium.*

<* While the effect of tidal friction is to decrease the rate of rotation, the still-continued contraction of the Earth has the effect of increasing it. How the difference between these conflicting effects is to be ascertained it is not easy to see.>

It is needless to show in detail how those movements which the Sun's rays generate in the air and water on the Earth's surface, and through them in the Earth's solid substance,* one and all teach the same general truth. Evidently the winds and waves and streams, as well as the denudations and depositions they effect, illustrate on a grand scale, and in endless modes, that gradual dissipation of motions described in the first section, and the consequent tendency towards a balanced distribution of forces. Each of these sensible motions, produced directly or indirectly by integration of those insensible motions communicated from the Sun, becomes divided and subdivided into motions less and less sensible; until by gradual or sudden arrest of each, and production of its equivalent in molecular motion, there is an escape of it into space in the shape of thermal undulations. In their totality, these complex motions constitute a dependent moving equilibrium. As we before saw there is traceable throughout them an involved combination of rhythms. The unceasing circulation of water from the ocean to the land and from the land back to the ocean, is a type of these various compensating actions which, in the midst of all the irregularities produced by their mutual interferences, maintain an average. And in this, as in other equilibrations of the third order, we see that the energy ever in course of dissipation, is ever renewed from without: the rises and falls in the supply being balanced by rises and falls in the expenditure; as witness the variations of meteorologic activity in northern zones caused by changes of the seasons. But the fact it chiefly concerts us to note is that this process must go on bringing things ever nearer to complete rest. These mechanical movements, meteorologic and geologic, which are continually being equilibrated, both temporary by counter-movements and permanently by the dissipation of such movements and counter-movements, will slowly diminish as the quantity of force received from the Sun diminishes. As the insensible motions propagated to us from the centre of our system become feebler, the sensible motions here produced by them must decrease; and at that remote period when the solar heat has ceased to be appreciable, there will no longer be any appreciable re-distributions of matter on the surface of our planet.

<* Until I recently consulted his Outlines of Astronomy on another question, I was not aware that so far back as 1833, Sir John Herschel had pointed out that "the sun's rays are the ultimate source of almost every motion which takes place on the surface of the earth." He expressly includes geologic, meteorologic, and vital actions; as also those which we produce by the combustion of coal.>

Thus, all terrestrial changes are incidents in the course of cosmical equilibration. It was before pointed out (§69), that of the incessant alterations which the Earth's crust and atmosphere undergo, those which are not due to the action of the moon and to the still-progressing motion of the Earth's substance towards its centre of gravity, are due to the still-progressing motion of the Sun's substance towards its centre of gravity. Here it is to be remarked that this continuance of integration in the Earth and in the Sun, is a continuance of that transformation of sensible motion into insensible motion which we have seen ends in equilibrium; and that the arrival in each case at the extreme of integration, is the arrival at a state in which no more sensible motion remains to be transformed into insensible motion — a state in which the forces producing integration and the forces opposing integration have become equal.

§173. Every living body exhibits, in a four-fold form, the process we are tracing out — exhibits it from moment to moment in the balancing of mechanical forces; from hour to hour in the balancing of functions; from year to year in the changes of state that compensate changes of conditions; and finally in the arrest of vital movements at death. Let us consider the facts under these heads.

The sensible motion constituting each visible action of an animal, is soon brought to a close by some opposing force within or without the animal. When a man's arm is raised, the motion given to it is antagonized partly by gravity and partly by the internal resistances consequent on structure; and its motion, thus suffering continual deduction, ends when the arm has reached a position at which the forces are equilibrated. The limits of each systole and diastole of the heart, severally show us a momentary equilibrium between muscular strains that produce opposite movements; and each gush of blood has to be immediately followed by another because the rapid dissipation of its momentum would otherwise soon bring the circulating mass to a stand. As much in the actions and reactions going on among the internal organs, as in the mechanical balancing of the whole body there is at every instant a progressive equilibration of the motions at every instant produced. Viewed in their aggregate, and as forming a series, the organic functions constitute a dependent moving equilibrium, a moving equilibrium of which the motive power is ever being dissipated through the special equilibrations just exemplified, and is ever being renewed by the taking in of additional motive power. The force stored up in food continually adds to the momentum of the vital actions, as much as is continually deducted from them by the forces overcome. All the functional movements thus maintained are rhythmical (§85); by their union compound rhythms of various lengths and complexities are produced; and in these simple and compound rhythms, the process of equilibration, besides being exemplified at each extreme of every rhythm, is seen in the habitual preservation of a constant mean, and in the re-establishment of that mean when accidental causes have produced divergence. from it. When, for instance, there is a great expenditure of muscular energy, there arises a reactive demand on those stores of energy which are laid up in the form of consumable matter throughout the tissues: increased respiration and increased circulation aid an extra genesis of force, that counterbalances the extra dissipation of force. This unusual transformation of molecular motion into sensible motion, is presently followed by an unusual absorption of food — the source of molecular motion; and the prolonged draft on the spare capital in the tissues, is followed by a prolonged rest, during which the abstracted capital is replaced. If the deviation from the ordinary course of the functions has been so great as to derange them, as when violent exertion produces loss of appetite and loss of sleep, an equilibration is still eventually effected. Providing the disturbance is not such as to destroy life (in which case complete equilibration is suddenly effected), the ordinary balance is by-and-by re-established: the returning appetite is keen in proportion as the waste has been large; while sleep, sound and prolonged, makes up for previous wakefulness. Not even when some extreme excess has wrought a derangement that is never wholly rectified, is there an exception to the general law; for in such cases the cycle of the functions is, after a time, equilibrated about a new mean state, which thenceforth becomes the normal state of the individual. And this process exemplifies in a large way what physicians call the vis medicatrix naturae. The third form of equilibration displayed by organic bodies, is a sequence of that just illustrated. When, through a change of habit or circumstance, an organism is permanently subject to some new influence, or different amount of an old influence, there arises, after more or less disturbance of the organic rhythms, a balancing of them around the new average condition produced by this additional influence. if the quantity of motion to be habitually generated by a muscle becomes greater than before, its nutrition becomes greater than before. if the expenditure of the muscle bears to its nutrition, a greater ratio than expenditure bears to nutrition in other parts of the system, the excess of nutrition becomes such that the muscle grows. And the cessation of its growth is the establishment of a balance between the daily waste and the daily repair. The like is manifestly the case with all organic modifications consequent on changes of climate or food. If we see that a different mode of life is followed, after a period of derangement, by some altered condition of the system — if we see that this altered condition, becoming by-and-by established, continues without further change; we have no alternative but to say that the new forces brought to bear on the system, have been compensated by the opposing forces they have evoked. And this is the interpretation of the process called adaptation. Finally, each organism illustrates the law in the ensemble of its life. At the outset it daily absorbs under the form of food, an amount of force greater than it daily expends; and the surplus is daily equilibrated by growth. As maturity is approached this surplus diminishes; and in the perfect organism the day's absorption of latent energy balances the day's expenditure of actual energy. That is to say, during adult life there is continuously exhibited an equilibrium of the third order. Eventually, the daily loss begins to outbalance the daily gain, and there results a diminishing amount of functional action; the organic rhythms extend less and less widely on each side of the medium state; and there finally comes that complete equilibrium we call death.

The ultimate structural state accompanying that ultimate functional state towards which an organism tends, may be deduced from one of the propositions set down in the opening section of this chapter. We saw that the limit of heterogeneity is reached when the equilibration of any aggregate becomes complete — that the re-distribution of matter can continue so long only as there continues some motion unbalanced. What is the implication in the case of organic aggregates? We have seen that to maintain the moving equilibrium of one, requires the habitual genesis of internal forces corresponding in number, directions, and amounts to the external incident forces — as many inner functions, single or combined, as there are single or combined outer actions to be met. But functions are the correlatives of organs; amounts of functions are, other things equal, the correlatives of sizes of organs; and combinations of functions the correlatives of connexions of organs. Hence the structural complexity accompanying functional equilibrium, is definable as one in which there are as many specialized parts as are capable, separately and jointly, of counteracting the separate and joint forces amid which the organism exists. And this is the limit of organic heterogeneity. to which Man has approached more nearly than any other creature.

Groups of organisms display this universal tendency towards a balance very obviously. in §85, every species of plant and animal was shown to be perpetually undergoing a rhythmical variation in number — now from abundance of food or absence of enemies rising above its average; and then, by a consequent scarcity of food or abundance of enemies, being depressed below its average. And here we have to observe that there is thus maintained an equilibrium between the sum of those forces which result in the increase of each race, and the sum of those forces which result in its decrease. Either limit of variation is a point at which the one set of forces, before in excess of the other, is counterbalanced by it. And amid these oscillations produced by their conflict, lies that average number of the species at which its expansive tendency is in equilibrium with surrounding repressive tendencies. Nor can it be questioned that this balancing of the preservative and destructive forces which we see going on in every race, must necessarily go on. Increase of number cannot but continue until increase of mortality stops it; and decrease of number cannot but continue until it is either arrested by fertility or extinguishes the race entirely.

§174. The equilibrations of those nervous actions which constitute the obverse face of mental life, may be classified in like manner with those which constitute what we distinguish as bodily life. We may deal with them in the same order.

Each pulse of nerve force from moment to moment generated, (and it was explained in §86 that nerve currents are not continuous but rhythmical,) is met by counteracting forces, in overcoming which it is dispersed and equilibrated. Such part of it as does not work mental changes works bodily changes — contractions of the involuntary muscles, the voluntary muscles, or both; as also some stimulation of secreting organs. That the movements thus initiated are ever being brought to a close by the opposing forces they evoke, we have just seen; and here it is to be observed that the like holds with the cerebral changes thus initiated. The arousing of a thought or feeling, involves the overcoming of a certain resistance: instance the fact that where the association of mental states has not been frequent, a sensible effort is needed to call up the one after the other; instance the fact that during nervous prostration there is a comparative inability to think — the ideas will not follow one another with the ordinary rapidity; instance the converse fact that at times of unusual energy, natural or artificial, thinking is easy, and more numerous, more remote, or more difficult connexions of ideas are formed. That is to say, the wave of nervous energy each instant generated, propagates itself throughout body and brain, along those channels which the passing conditions render lines of least resistance; and spreading widely in proportion to its amount, ends only when it is equilibrated by the resistances it everywhere meets. If we contemplate mental actions as extending over hours and days, we discover equilibrations analogous to those hourly and daily established among the bodily functions. This is seen in the daily alternation of mental activity and mental rest — the forces expended during the one being compensated by the forces acquired during the other. It is also seen in the recurring rise and fall of each desire. Each desire reaching a certain intensity, is equilibrated either by expenditure of the energy it embodies in the desired actions, or, less completely, in the imagination of such actions: the process ending in that satiety or that comparative quiescence, forming the opposite limit of the rhythm. And it is further manifest under a two-fold form on occasions of intense joy or grief. Each paroxysm, expressing itself in violent actions and loud sounds, presently reaches an extreme whence the counteracting forces produce return to a condition of moderate excitement; and the successive paroxysms, finally diminishing in intensity, end in a mental equilibrium either like that before existing, or having a partially different medium state. But the kind of mental equilibration to be especially noted, is that shown in the establishment of a correspondence between relations among our ideas and relations in the external world. Each outer connexion of phenomena which we are capable of perceiving, generates, through accumulated experiences, an inner connexion of mental states; and the result towards which this process tends, is the formation of a mental connexion having a relative strength that answers to the relative constancy of the physical connexion represented. In conformity with the general law that motion pursues the line of least resistance, and that, other things equal, a line once taken by motion is made a line which will be more readily taken by future motion, we have seen that the ease with which nervous impressions follow one another is, other things equal, great in proportion to the number of times they have been repeated together in experience. Hence, corresponding to such an invariable relation as that between the resistance of an object and some extension possessed by it, there arises an indissoluble connexion in consciousness; and this connexion, being as absolute internally as the answering one is externally, undergoes no further change — the inner relation is in perfect equilibrium with the outer relation. Conversely, it happens that, answering to such uncertain relations of phenomena as that between clouds and rain, there arise relations of ideas of like uncertainty; and if, under given aspects of the sky, the tendencies to infer fair or foul weather, corresponds to the frequencies with which fair or foul weather follows such aspects, the accumulation of experiences has balanced the mental sequences and the physical sequences. When it is remembered that between these extremes there are countless orders of external associations having different degrees of constancy, and that during the evolution of intelligence there arise answering eternal associations having different degrees of cohesion; it will be seen that there is a progress towards equilibrium between the relations of thought and the relations of things. The like general truths are exhibited in the process of moral adaptation, which is a continual approach to equilibrium between the emotions and the kinds of conduct required by surrounding conditions. Just as repeating the association of two ideas facilitates the excitement of the one by the other, so does each discharge of feeling into action render the subsequent discharge of such feeling into such action more easy. Thus it happens that if an individual is placed permanently in conditions which demand more action of a special kind than has before been requisite, or than is natural to him — if by every more frequent or more lengthened performance of it under such pressure, the resistance is somewhat diminished; then, dearly, there is an advance towards a balance between the demand for this kind of action and the supply of it. Either in himself, or in his descendants continuing to live under these conditions, enforced repetition must at length bring about a state in which this mode of directing the energies will be no more repugnant than the other modes previously natural to the race. Hence the limit towards which emotional modification perpetually tends, is a combination of desire that correspond to the various orders of activity which the circumstances of life call for. In acquired habits, and in the moral differences of races and nations that are produced by habits maintained through successive generations, we have illustrations of this progressive adaptation, which can cease only with the establishment of equilibrium between constitution and conditions.

§175. Each society displays the process of equilibration in the continuous adjustment of its population to its means of subsistence. A tribe of men living on wild animals and fruits, is manifestly, like every tribe of inferior creatures, always oscillating from side to side of that average number which the locality can support. Though, by artificial production unceasingly improved, a superior race continually alters the limit which external conditions put to population; yet there is ever a checking of population at the temporary limit reached. It is true that where the limit is being rapidly changed, as among ourselves, there is no actual stoppage: there is only a rhythmical variation in the rate of increase. But in noting the causes of this rhythmical variation — in watching how, during periods of abundance, the proportion of marriages increases, and how it decreases during periods of scarcity, it will be seen that the expansive force produces unusual advance whenever the repressive force diminishes, and vice versa; and thus there is as near a balancing of the two as the changing conditions permit.

The internal actions constituting social functions, exemplify the general principle no less clearly. Supply and demand are continually being adjusted throughout all industrial processes; and this equilibration is interpretable in the same way as preceding ones. The production and distribution of a commodity imply a certain aggregate of forces causing special kinds and amounts of motion. The price of this commodity, is the measure of a certain other aggregate of forces expended in other kinds and amounts of motion by the labourer who purchases it. And the variations of price represent a rhythmical balancing of these forces. Every rise or fall in the value of a particular security, implies a conflict of forces in which some, becoming temporarily predominant, cause a movement that is. presently arrested, or equilibrated, by the increased opposing forces; and amid these daily and hourly oscillations lies a more slowly-varying medium, into which the value ever tends to settle, and would settle but for the constant addition of new influences. As in the individual organism so in the social organism, functional equilibrations generate structural equilibrations. When on the workers in any trade there comes an increased demand, and when in return for the increased supply they receive an amount of other commodities larger than before — when, consequently, the resistances overcome by them in sustaining life are less than the resistances overcome by other workers; there results a flow of other workers into this trade. This flow continues until the extra demand is met, and the wages so far fall that the total resistance overcome in obtaining a livelihood, is as great in this newly-adopted occupation as in the occupations whence it drew recruits. The occurrence of motion along lines of least resistance, was before shown to necessitate the growth of population in those places where the labour required for self-maintenance is the smallest; and here we further see that those engaged in any such advantageous locality, must multiply till there arises an approximate balance between its population and that of others available by the same citizens.

These various industrial actions and reactions constitute a dependent moving equilibrium like that maintained among the functions of an individual organism, and like it tends ever to become more complete. During early stages of social evolution, while the resources of the locality inhabited are unexplored and the arts of production undeveloped, there is never anything more than a temporary and partial balancing of such actions. But when a society approaches the maturity of that type on which it is organized, the various industrial activities settle down into a comparatively constant state. Moreover, advance in organization, as well as advance in growth, is conducive to a better equilibrium of industrial functions. While the diffusion of mercantile information is slow and the means of transport deficient, the adjustment of supply to demand is very imperfect. Great over-production of a commodity is followed by great under-production, and there results a rhythm having extremes that depart widely from the mean state in which demand and supply are equilibrated. But when good roads are made and there is a rapid diffusion of printed or written intelligence, and still more when railways and telegraphs come into existence — when the periodical fairs of early days grow into weekly markets, and these into daily markets, there is gradually produced a better balance of production and consumption: the rapid oscillations of price within narrow limits on either side of a comparatively uniform mean, indicate a near approach to equilibrium. Evidently this industrial progress has for its limit, that which Mr. Mill has called "the stationary state." When population shall have become dense over all habitable parts of the globe; when the resources of every region have been fully explored; and when the productive arts admit of no further improvements; there must result an almost complete balance, both between the fertility and mortality in each society, and between its producing and consuming activities. Each society will exhibit only minor deviations from its average number, and the rhythm of its industrial functions will go on from day to day and year to year with comparatively insignificant perturbations.

One other kind of social equilibration has still to be considered: — that which results in the establishment of governmental institutions, and which becomes complete as these institutions fall into harmony with the desires of the people. Those aggressive impulses inherited from the pre-social state — those tendencies to seek self-satisfaction regardless of injury to other beings, which are essential to a predatory life, constitute an anti-social force tending ever to cause conflict and separation. Contrariwise, those desires which can be fulfilled only by co-operation and those which find satisfaction through intercourse with fellow-men, as well as those resulting in what we call loyalty, are forces tending to keep the units of a society together. On the one hand, there is in each man more or less of resistance against restraints imposed on his actions by other men — a resistance which, tending ever to widen each man's sphere of action, and reciprocally to limit the spheres of action of other men, constitutes a repulsive force mutually exercised by the members of a social aggregate. On the other hand, the general sympathy of man for man and the more special sympathy of each variety of man for others of the same variety, together with allied feelings which the social state gratifies, act as an attractive force, tending ever to keep united those who have a common ancestry. And since the resistances to be overcome in satisfying the totality of their desires when living separately, are greater than the resistances to be overcome in satisfying the totality of their desires when living together, there is a residuary force that prevents separation. Like other opposing forces, those exerted by citizens on one another produce alternating movements which, at first extreme, undergo gradual diminution on the way to ultimate equilibrium. In small, undeveloped societies, marked rhythms result from these conflicting tendencies. A tribe that has maintained its unity for a generation or two, reaches a size at which it will no longer hold together; and, on the occurrence of some event causing unusual antagonism among its members, divides. Each primitive nation exhibits wide oscillations between an extreme in which the subjects are under rigid restraint, and an extreme in which the restraint fails to prevent rebellion and disintegration. In more advanced nations of like type, we always find violent actions and reactions of the same essential nature: "despotism tempered by assassination," characterizing a political state in which unbearable repression from time to time brings about a bursting of bonds. Among ourselves the conflicts between Conservatism (which stands for the restraints of society over the individual) and Reform (which stands for the liberty of the individual against society), fall within slowly approximating limits. so that the temporary predominance of either produces a less marked deviation from the medium state — a smaller disturbance of the moving equilibrium.

Of course in this case, as in preceding cases, there is involved a limit to the increase of heterogeneity. A few pages back, it was shown that an advance in mental evolution is the establishment of some further internal action corresponding to some further external action. We inferred that each such new function, involving some new modification of structure, implies an increase of heterogeneity; and that thus, increase of heterogeneity must go on while there remain any outer relations affecting the organism which are unbalanced by inner relations. Evidently the like must simultaneously take place with society. Each increment of heterogeneity in the individual implies, as cause or consequence, some increment of heterogeneity in the arrangements of the aggregate of individuals. And the limit to social complexity can be reached only with the establishment of the equilibrium, just described, between social and individual forces.

§176. Here presents itself a final question, which has probably been taking shape in the minds of many while reading this chapter. "If Evolution of every kind is an increase in complexity of structure and function that is incidental to the universal process of equilibration, and if equilibration must end in complete rest, what is the fate towards which all things tend? If the Solar System is slowly dissipating its energies — if the Sun is losing his heat at a rate which will tell in millions of years — if with decrease of the Sun's radiations there must go on a decrease in the activity of geologic and meteorologic processes as well as in the quantity of vegetable and animal life — if Man and Society are similarly dependent on this supply of energy which is gradually coming to an end; are we not manifestly processing towards omnipresent death?"

That such a state must be the outcome of the changes everywhere going on, seems beyond doubt. Whether any ulterior process may reverse these processes and initiate a new life, is a question to be considered hereafter. For the present it must suffice that the end of all the transformations we have traced, is quiescence. This admits of a priori proof. The law of equilibration, not less than the preceding general laws, is deducible from the ultimate datum of consciousness.

The forces of attraction and repulsion being, as shown in §74, universally co-existent, it follows that all motion is motion under resistance: either that exercised on the moving body by other bodies, or that exercised by the medium traversed. There are two corollaries. The first is that deductions perpetually made by the communication of motion to that which resists, cannot but bring the motion of the body to an end in a longer or shorter time. The second is that the motion of the body cannot cease until these deductions destroy it. In other words, movement must continue while equilibration is incomplete, and equilibration must eventually become complete. Both these are manifest deductions from the persistence of force. Hence this primordial truth is our warrant for the conclusions that the changes which Evolution presents cannot end until equilibrium is reached, and that equilibrium must at last be reached.

At the same time it follows that in every aggregate having compound motions, there results a comparatively early dissipation of the motions which are smaller and much resisted, followed by long-continuance of the larger and less resisted motions; and that so there arise moving equilibria. Hence, also, may be inferred the tendency to conservation of such moving equilibria. For any new motion given to the parts of a moving equilibrium by a disturbing force, must either be such that it cannot be dissipated before the pre-existing motions, in which case it brings the moving equilibrium to an end. or else it must be such that it can be dissipated before the pre-existing motions, in which case the moving equilibrium is re-established.

Thus from the persistence of force follow, not only the various direct and indirect equilibrations going on around, together with th at cosmical equilibration which brings Evolution under all its forms to a close, but also those less manifest equilibrations shown in the readjustments of moving equilibria that have been disturbed. By this ultimate principle is provable the tendency of every organism, disordered by some unusual influence, to return to a balanced state. To it also may be traced the capacity, possessed in a slight degree by individuals and in a greater degree by species, of becoming adapted to new circumstances. And not less does it afford a basis for the inference that there is a gradual advance towards harmony between man's mental nature and the conditions of his existence.

Chapter 23


§177. When, in Chapter 22, we glanced at the cycle of changes through which every existence passes, in a short time or in a time almost infinitely long — when the opposite re-distributions of matter and motion implied were severally distinguished as Evolution and Dissolution. the natures of the two, and the conditions under which they respectively occur, were specified in general terms. Since then, we have contemplated the phenomena of Evolution in detail, and have followed them out to those states of equilibrium in which they all end. To complete the argument we must now contemplate, somewhat more in detail than before, the complementary phenomena of Dissolution. Not, indeed, that we need dwell long on Dissolution, which has none of those various and interesting aspects which Evolution presents; but something more must be said than has yet been said.

It was shown that neither of these two antagonist processes goes on unqualified by the other, and that a movement towards either is a differential result of the conflict between them. An evolving aggregate, while on the average losing motion and integrating, is always, in one way or other, receiving some motion and to that extent disintegrating; and after the integrative changes have ceased to predominate, the reception of motion, though perpetually checked by its dissipation, constantly tends to produce a reverse transformation, and eventually does produce it. When Evolution has run its course — when an aggregate has reached that equilibrium in which its changes end, it thereafter remains subject to all actions in its environment which may increase the quantity of motion it contains, and which in course of time are sure, either slowly or suddenly, to give its parts such excess of motion as will cause disintegration. According as its size, its nature, and its conditions determine, its dissolution may come quickly or may be indefinitely delayed — may occur in a few days or may be postponed for billions of years. But exposed as it is to the contingencies not simply of its immediate neighbourhood but of a Universe everywhere in motion, the time must at last come when, either alone or in company with surrounding aggregates, it has its parts dispersed.

The process of dissolution so caused we have here to look at as it takes place in aggregates of different orders. The course of change being the reverse of that hitherto traced, we may properly take the illustrations of it in the reverse order — beginning with the most complex and ending with the most simple.

§178. Regarding the evolution of a society as at once an increase in the number of individuals integrated into a corporate body, an increase in the masses and varieties of the parts into which this corporate body divides, as well as of the actions called their functions, and an increase in the degree of combination among these masses and their functions; we shall see that social dissolution conforms to the general law in being, materially considered, a disintegration, and, dynamically considered, a decrease in the movements of wholes and an increase the movements of parts; while it further conforms to the general law in being, caused by an excess of motion in some way or other received from without.

It is obvious that the social dissolution which follows the aggression of mother nation, and which, as history shows us, is apt to occur when social evolution has ended and decay has begun, is, under its broadest, aspect, the reception of a new external motion; and when, as sometimes happens, the conquered society is dispersed, or when its component divisions fall apart, its dissolution is literally a cessation of those corporate movements which the society, both in its army and in its industrial bodies, presented, and a lapse into individual or uncombined movements.

Again, social disorder, however caused, entails a decrease of integrated movements and an increase of disintegrated movements. As the disorder progresses the political actions previously combined become uncombined: there arise the antagonistic actions of riot or revolt. Simultaneously, the industrial and commercial processes that were co-ordinated throughout the body politic, are broken up; and only the local, or small, trading transactions continue. And each further disorganizing change diminishes the joint operations by which men satisfy their wants, and leaves them to satisfy their wants, as best they can, by separate operations. Of the way in which such distintegrations are set up in a society that has evolved to the limit of its type, and reached a state of moving equilibrium, a good illustration is furnished by Japan. The finished fabric into which its people have organized themselves, maintained an almost constant state so long as it was preserved from fresh external forces. But as soon as it received an impact from European civilization, partly by armed aggression, partly by commercial impulse, partly by the influence of ideas, this fabric began to fall to pieces. There is now in progress a political dissolution.* Probably a political reorganization will follow; but, be this as it may, the change thus far produced by an outer action is a change towards dissolution — a change from integrated motions to disintegrated motions.

<* This was written in 1867.>

Even where a society that has developed into the highest form permitted by the characters of its units, begins to dwindle and decay, the progressive dissolution is still essentially of the same nature. Decline of numbers is, in such case, brought about partly by emigration; for a society having the fixed structure in which evolution ends, is one that will not yield and modify under pressure of population: so long as its structure is plastic it is still evolving. Hence the surplus population is continually dispersed: the influences brought to bear on the citizens by other societies cause their detachment, and there is an increase of the uncombined motions of units instead of an increase of combined motions. Gradually as the society becomes still less capable of changing into the form required for successful competition with more plastic societies, the number of citizens who can live within its unyielding framework becomes positively smaller. Hence it dwindles both through continued emigration and through the diminished multiplication that follows innutrition. And this further dwindling is similarly a decrease in the total quantity of combined motion and an increase in the quantity of uncombined motion — as we shall presently see when we come to deal with individual dissolution.

Considering, then, that social aggregates differ so much from aggregates of other kinds, formed, as they are, of units held together loosely and indirectly, in such variable ways by such complex forces, the processes of dissolution among them conforms to the general law quite as clearly as could be expected.

§179. When from these super-organic aggregates we descend to organic aggregates, the truth that Dissolution is a disintegration of matter caused by the reception of additional motion from without, becomes easily demonstrable. We will look first at the transformation and afterwards at its cause.

Death, or that final equilibration which precedes dissolution, is the bringing to a close all those many conspicuous integrated motions that arose during evolution. The impulsions of the body from place to place first cease; presently the limbs cannot be stirred; later still the respiratory actions stop; finally the heart becomes stationary and, with it, the circulating fluids. That is, the transformation of molecular motion into the motion of masses, comes to an end. The process of decay involves an increase of insensible movements; since these are far greater in the gases generated than they are in the fluid-solid matters out of which the gases arise. Each of the complex chemical units composing an organic body, possesses a rhythmic motion in which its many component units jointly partake. When decomposition breaks up these complex molecules, and their constituents assume gaseous forms, there is, besides that increase of motion implied by diffusion, a resolution of such motions as the complex molecules possessed, into motions of their constituent molecules. So that in organic dissolution we have, first, an end put to that transformation of the motions of units into the motions of aggregates, which constitutes evolution, dynamically considered; and we have afterwards, though in a subtler sense, a transformation of the motions of aggregates into the motions of units. Still it is not thus shown that organic dissolution answers to the general definition of dissolution — the absorption of motion and concomitant disintegration of matter. The disintegration of matter is, indeed, conspicuous enough; but the absorption of motion is not conspicuous. True, the fact that motion has been absorbed may be inferred from the fact that particles previously integrated into a solid mass, occupying a small space, have most of them moved away from one another and now occupy a great space; for the motion implied by this expansion must have been obtained from somewhere. But its source is not obvious. A little search, however, will bring us to its derivation.

At a temperature below the freezing point of water, decomposition of organic matter does not take place. Dead bodies kept at this temperature are prevented from decomposing for an indefinitely long period: witness the frozen carcases of mammoths (elephants of a species long ago extinct) that are found imbedded in the ice at the mouths of Siberian rivers; and which, though they have been there for many thousands of years, have flesh so fresh that when at length exposed it is devoured by wolves. What, now, is the meaning of such exceptional preservations? A body kept below freezing point, is a body which receives very little heat by radiation or conduction; and the reception of but little heat is the reception of but little molecular motion. That is to say,in an environment which does not furnish it with molecular motion passing a certain amount, an organic body does not undergo dissolution. Confirmatory evidence is yielded by the variations in rate of dissolution which accompany variations of temperature. All know that in cool weather the organic substances used in our households keep longer, as we say, than in hot weather. Equally certain, if less familiar, is the fact that in tropical climates decay proceeds much more rapidly than in temperate climates. Thus, dispersion of the dead body into gases is rapid in proportion as the molecular motion received from without is great. The still-quicker decompositions produced by exposure to artificially-raised temperatures, afford further proofs: instance those which occur in cooking. The charred surfaces of parts much heated, show us that the molecular motion absorbed has served to dissipate in gaseous forms all the elements but the carbon.

The nature and causes of Dissolution are thus clearly displayed by the aggregates which so clearly display the nature and causes of Evolution. One of these aggregates being made of that peculiar matter to which a large quantity of constitutional motion gives great plasticity, and the ability to evolve into a highly complex form, (§103); it results that after evolution has ceased, a small amount of molecular motion added to that already contained in its peculiar matter, suffices to cause dissolution. Though at death there is reached an equilibrium among the sensible masses, or organs, which make up the body; yet, as the insensible units or molecules of which these organs consist are chemically unstable, small incident forces suffice to overthrow them, and hence disintegration proceeds rapidly.

§180. Most inorganic aggregates, having arrived at dense forms in which comparatively little motion is retained, remain long without marked changes. Each has lost so much motion in passing from the unintegrated to the integrated state, that much motion must be given to it to cause resumption of the unintegrated state; and an immense time may elapse before there occur in the environment, changes great enough to communicate to it the requisite quantity of motion. We will look first at those few inorganic aggregates which retain much motion, and therefore readily undergo dissolution.

Among these are the liquids and volatile solids which dissipate under ordinary conditions — water that evaporates, camphor that wastes away by the dispersion of its molecules. In all such cases motion is absorbed; and always the dissolution is rapid in proportion as the quantity of heat or motion which the mass receives from its environment is great. Next come the cases in which the molecules of a highly integrated or solid aggregate, are dispersed among the molecules of a less integrated or liquid aggregate; as in aqueous solutions. One evidence that this disintegration of matter has for its concomitant the absorption of motion, is that soluble substances dissolve the more quickly the hotter the water: supposing always that no elective affinity comes into play. Another and still more conclusive evidence is, that when crystals of a given temperature are placed in water of the same temperature, the process of solution is accompanied by a fall of temperature — often a very great one. Omitting instances in which some chemical action takes place between the salt and the water, it is a uniform law that the motion which disperses the molecules of the salt through the water, is at the expense of the molecular motion possessed by the water. An allied and still better example is furnished by cases in which the dissolution of two solids results from mixing them, as happens with snow and salt. Here dissolution necessitates so great an absorption of molecular motion as greatly to lower the temperature of the liquid produced.

Masses of sediment accumulated into strata, afterwards compressed by many thousands of feet of superincumbent strata, and reduced in course of time to a solid state, may remain for untold millions of years unchanged; but in subsequent millions of years they are inevitably exposed to disintegrating actions. Raised along with other such masses into a continent, denuded and exposed to rain, frost, and the grinding actions of glaciers, they have their particles gradually separated, carried away, and widely dispersed. Or when, as otherwise happens, the encroaching sea arrives, the undermined cliffs formed of them fall from time to time; the waves, rolling about the small pieces, and in storms knocking together the larger blocks, reduce them to boulders and pebbles, and at last to sand and mud. Even if portions of the disintegrated strata accumulate into shingle banks which afterwards become solidified, the process of dissolution, arrested though it may be for some enormous geologic period, is finally resumed. As many a shore shows us, the conglomerate itself is sooner or later subject to the like processes; and its cemented masses of heterogeneous components are broken up and worn away by impact and attrition — that is, by communicated mechanical motion.

When not thus effected, the disintegration is effected by communicated molecular motion. A consolidated stratum in some area of subsidence, brought down nearer and nearer to the regions occupied by molten matter, comes eventually to have its particles brought to a plastic state by heat, or finally melted down into liquid. Whatever may be its subsequent transformations, the transformation then exhibited by it is an absorption of motion and disintegration of matter.

Thus be it simple or compound, small or large, a crystal or a mountain-chat, every inorganic aggregate on the Earth undergoes, at some time or other, a reversal of those changes undergone during its evolution. Not that it usually passes back from the perceptible into the imperceptible, during any period in which it is or can be exposed to human observation. It does not become aeriform and invisible, as organic aggregates do in great part, though not wholly. But still its disintegration and dispersion carry it some distance on the way towards the imperceptible; and there are reasons for thinking that its arrival there is but delayed. At a period immeasurably remote, every such inorganic aggregate, along with all undissipated remnants of organic aggregates, must be reduced to a state of gaseous diffusion, and so complete the cycle of its changes.

§181. For the Earth as a whole, when it has gone through the entire series of its ascending transformations, must remain exposed to the contingencies of its environment; and in the course of those ceaseless changes going on throughout a Universe of which all parts are in motion, must, at some period beyond the utmost stretch of imagination, be subject to energies sufficient to cause its complete disintegration. Let us glance at the energies competent to disintegrate it.

In his essay on "The Inter-action of Natural Forces," Prof. Helmholtz states the thermal equivalent of the Earth's movement through space, as calculated on the now received datum of Mr. Joule. "If our Earth," he says, "were by a sudden shock brought to rest in her orbit — which is not to be feared in the existing arrangement of our system — by such a shock a quantity of heat would be generated equal to that produced by the combustion of fourteen such Earths of solid coal. Making the most unfavourable assumption as to its capacity for heat, that is, placing it equal to that of water, the mass of the Earth would thereby be heated 11,200 degrees; it would therefore be quite fused, and for the most part reduced to vapour. If then the Earth, after having been thus brought to rest, should fall into the Sun, which of course would be the case, the quantity of heat developed by the shock would be 400 times greater." Now though this calculation seems to be nothing to the purpose, since the Earth is not likely to be suddenly arrested in its orbit and not likely therefore suddenly to fall into the Sun; yet, as before pointed out (§171), there is a force at work which it is held must at last bring the Earth into the Sun. This force is the resistance of the ethereal medium. From ethereal resistance is inferred a retardation of all moving bodies in the Solar System — a retardation which some astronomers contend even now shows its effects in the relative nearness to one another of the orbits of the older planets. If, then, retardation is going on, there must come a time, no matter how remote, when the slowly diminishing orbit of the Earth will end in the Sun; and though the quantity of molar motion to be then transformed into molecular motion, will not be so great as that which the calculation of Helmholtz supposes, it will be great enough to reduce the substance of the Earth to a gaseous state.

This dissolution of the Earth and, at intervals, of every other planet, is not, however, a dissolution of the Solar System. All the changes exhibited throughout the Solar System, are incidents accompanying the integration of the entire matter composing it: the local integration of which each planet is the scene, completing itself long before the general integration is complete. But each secondary mass leaving gone through its evolution and reached a state of equilibrium among its parts (supposing that the available time suffices, which in the cases of Jupiter and Saturn it may not), thereafter continues in its extinct state, until, by the still-progressing general integration, it is brought into the central mass. And though each such union of a secondary mass with the central mass, implying transformation of molar motion into molecular motion, causes partial diffusion of the total mass formed, and adds to the quantity of motion that has to be dispersed in the shape of light and heat; yet it does but postpone the period at which the total mass must become completely integrated, and its excess of contained motion radiated into space.

§182. Here we come to the question raised at the close of the last chapter — Does Evolution as a whole, like Evolution in detail, advance towards complete quiescience? Is that motionless state called death, which ends Evolution in organic bodies, typical of the universal death in which Evolution at large must end? And have we thus to contemplate as the outcome of things, a boundless space holding here and there extinct Suns, fated to remain for ever without further change?

To so speculative an inquiry, none but a speculative answer is to be expected. Such answer as may be ventured, must be taken less as a positive answer than as a demurrer to the conclusion that the proximate result must be the ultimate result. If, pushing to its extreme the argument that Evolution must come to a close in complete equilibrium or rest, the reader suggests that for aught which appears to the contrary there must result a Universal Death which will continue indefinitely, two replies may be made. The first is that the evidence presented in the heavens at large implies that while of the multitudinous aggregates of matter it presents, most are passing through those stages — which must end in local rest, there are others which, having barely commenced the series of changes constituting Evolution, are on the way to become theatres of life. The second reply is that when we contemplate our Sidereal System as a whole, certain of the great facts which science has established imply potential renewals of life, now in one region now in another, followed, possibly, at a period unimaginably remote by a more general renewal. This conclusion is suggested when we take into account a factor not yet mentioned.

For hitherto we have considered only that equilibration which is taking place within our Solar System and within similar systems; taking no note of that immeasurably greater equilibration which remains to take place: ending those motions through space which such systems possess. That the stars, in old times called fixed, are all in motion, has now become a familiar truth, and that they are moving with velocities ranging from say 10 miles per second up to some 70 miles per second (which last is the velocity of a "runaway star" supposed to be passing through our Sidereal System) is a truth deduced from observations by modern astronomers. To be joined with this is the fact that there are dying stars and probably dead stars. Beyond the evidence furnished by the various kinds of light they emit, of which the red indicates relatively advanced age, there is the evidence that in some cases bright stars have attendants which are dark or almost dark: the most conspicuous case being that of Sirius, round which revolves a body of about one-third its size but yielding only 1/30000th part of its light — a star approaching to our Sun in size, which has gone out. The implication appears to be that beyond the luminous masses constituting the visible Sidereal System, there are non-luminous masses, perhaps fewer in number perhaps more numerous, which in common with the luminous ones are impelled by mutual gravitation. How then are to be equilibrated the motions of these vast masses, luminous and nonluminous, having high velocities?

This question may be divided into two, a major and a minor, of which the minor admits of something like an answer, while the major seems unanswerable.

§182a. Scattered through immensurable space, but more especially in and about the region of the Milky Way, are numerous star-clusters, varying in their characters from those which are hardly distinguishable from unusually rich portions of the heavens, to those which constitute condensed swarms of stars; kinds of which may be named, as at the one extreme, 24 Persei, 103 Cassiopeia and 32 Cygni, and at the other extreme, 13 Herculis and 2 Aquarei.* The varieties between these extremes were regarded by Sir William Herschel as implying progressive concentration; and in his opinion Sir John Herschel apparently agreed. Pursuing the argument the latter wrote: —

<* The clusters here named are exhibited in Dr. Isaac Roberts's splendid series of Photographs of Stars, Star-Clusters, and Nebulae (two vols.), in which also will be found the references presently to be made.>

"Among a crowd of solid bodies of whatever size, animated by independent and partially opposing impulses, motions opposite to each other must produce collision, destruction of velocity, and subsidence or near approach towards the centre of preponderant attraction; while those which conspire, or which remain outstanding after such conflicts, must ultimately give rise to circulation of a permanent character." (Outlines of Astronomy, 9th ed., p. 641.) The problem, however, is here dealt with purely as a mechanical one: the assumption being that the mutually arrested masses will continue as masses. Writing in 1849 Sir John Herschel did not take account of the results reached and verified during the few preceding years by Mayer and Joule, respecting the quantitative equivalence between motion and heat. But accepting, as we must now do, the conclusion drawn by Helmho1tz (§171) congruous with one previously drawn by Mayer, we are obliged to infer that stars moving at the high velocities acquired during concentration, will, by mutual arrest, be dissipated into gases of extreme tenuity constituting what we conceive as nebulous matter. When we infer this the problem becomes different; and a different conclusion seems unavoidable. For the diffused matter produced by such conflicts must form a resisting medium, occupying that central region of the cluster through which its members from, time to time pass in describing their orbits — a resisting medium which they cannot move through without having their velocities diminished. Every additional collision, by augmenting this resisting medium, and making the losses of velocity greater must aid in preventing the establishment of that equilibrium which would else arise; and so must conspire to produce more frequent collisions. And the nebulous matter thus formed, presently enveloping the whole cluster, must, by continuing to shorten the gyrations of the moving masses, entail an increasingly active integration and reactive disintegration of them, until they are all dissipated.*

<* I leave these three sentences as they stood in the revised edition of this work published in 1867, because evidence since obtained goes far to show that the process described is going on. In the photographs contained in the second volume of his Stars, Star-Clusters, and Nebulae, and by the accompanying description; Dr. Roberts shows that in some of them (as instance, M. 3 Canum Venaticorum) there is distinctly visible a nebulous central region, such as might be produced at early stages of the process described; and that he conceives such a process to be taking place is proved by his remarks on page 178.>

Products of the kind implied are presented in the large diffused, and irregular nebulae, such as the one in Orion Sir John Herschel describes them (p. 650) as "very great in extent," "irregular and capricious in their shapes," "no less so in the distribution of their light," and not having "any similarity of figure or aspect." And then he remarks that "they have one important character in common" — "they are all situated in or near the borders of the Milky Way." That is to say, they are found in that region of the heavens in which star-clusters also are most abundant. Thus in their distribution and in their characters these nebulae are congruous with the supposition that they have resulted from dissipation of clusters arising in the way described.

What may we say concerning the future of one of these vast irregular nebulae? The first remark is that as, in conformity with the foregoing speculation, it contains the matter not of one star but of many stars, so in conformity with its aspect it is not a nebulous mass of the kind out of which a single star or sun originates: being so large that it covers numerous interstellar spaces. The second remark is that when its widest diffusion has been reached concentration will commence, and the implication is that after an immense period a rotating nebula of one or other of the kinds so abundantly exemplified will result. That a spiral nebula is produced by concentration of one of these vast diffused masses, containing the matter of many stars, is an inference supported by the fact that in some spiral nebulae many stars and nebulous stars embedded within the spiral structure have manifestly been formed or are forming while the general concentration is going on — instance 74 Piscium, 100 Comae, and M. 51 Canum Venaticorum — and suggesting that a new concentrating cluster will eventually arise. If so, the implication appears to be that there will eventually again arise a process like that just suggested — collisions of concentrating masses and progressing diffusion until the nebulous form is again produced.

If in pursuance of this view we regard (1) the star-clusters variously condensed, (2) the diffused and irregular nebulae, (3) the spiral and other nebulae that are concentrating into star-systems, as exhibiting different stages of the same process, then the implication is that in many thousands of places throughout our Sidereal System there are going on alterations of Evolution and Dissolution. And this conception may be taken as a sufficient answer to the inference above drawn that equilibration must end in universal death — a speculative demurrer to a speculative conclusion.

§182b. There still presents itself the question which, unanswerable though it may be, we cannot ignore — What are we to think concerning the future of the visible Universe? To the conception of alternating evolutions and dissolutions taking place in multitudinous different parts of it, there must be joined the conception of it as either remaining in its present state or as changing; and that rises the question — Changing towards what other state? That its state must change is clear: the irregular distribution of it being such as to render even a temporary moving equilibrium impossible.

At the outset there arises the doubt whether our Sidereal System is an aggregate at all, in such sense as is implied by conformity to the law of Evolution and Dissolution — whether it does not transcend those limits implied by conformity to the law. When, reducing its stars and their distances to dimensions that may be imagined, we think of them as comparable to peas one hundred miles apart, the conception of them as forming a whole held together only by mutual gravitation seems somewhat strained. The assumed unity seems more questionable on observing the marks of independence in the dispersed parts. Besides multitudinous cases of the kind above described in which star-clusters apparently carry on their transformations irrespective of the Sidereal System as a whole, there are some far larger local transformations that appear to be of kindred nature. I refer to those going on in the Magellanic clouds or nubeculae, major and minor — two closely-packed agglomerations, not, indeed, of single stars only, but of single stars, of clusters regular and irregular, of nebula, and of diffused nebulosity. That these have been formed by mutual gravitation of parts once widely scattered, there is evidence in the barrenness of the surrounding celestial spaces: the nubecula minor especially, being seated, as Humboldt says, in "a kind of starless desert." And since the traits of these chaotic aggregates are such as do not consist with any process of evolution, we must infer that they are passing through the counter-process of dissolution: the resulting nebulous matter having already enveloped large portions of their miscellaneous components; a conclusion receiving support from the fact that while the one lies in a space devoid of stars the other has around it numerous outlying nebula and star-clusters, which must in course of time be drawn into it. Thus there are considerable difficulties in the way of regarding our Sidereal System as a whole, subject to the processes of evolution and dissolution.

Nevertheless sundry traits seem to imply that throughout a past so immense that the time occupied in the evolution of a solar or stellar system becomes by comparison utterly insignificant, there has been a gathering together of the matter of our Universe from a more dispersed state; and its disc-like form, or else annular form, indicated by the encircling appearance of the Milky Way, rises the thought that it has a combined motion within which all minor motions are included. Moreover the contrast between the galactic circle, with its closely packed millions of stars dotted with numerous star-clusters, and the regions about the galactic poles, in which the more regular nebula are chiefly congregated, yields further evidence that our Sidereal System has some kind of unity, and that during an immeasurable past it has undergone transformations due to general forces. If, then, we must contemplate the visible Universe as an aggregate, subject to processes of evolution and dissolution of the same essential nature as those traceable in minor aggregates, we cannot avoid asking what is likely to be its future.

In his Outlines of Astronomy (pp. 630-1), Sir John Herschel refers to speculations respecting the rotation of our Sidereal System in the plane of the galactic circle. Dismissing the hypothesis of Mädler that the centre of rotation is in the Pleiades, he thinks that no opinion can reasonably be formed whether rotation exists or not, until after some thirty or forty years of observations of a special class. In any case, however, the irregularities of the Milky Way necessitate the conclusion that there is going on, and must continue to go on, a general change of structure. The greater massiveness of it in the northern than in the southern hemisphere, the cleft form, the breach of continuity, the branchings, the narrow connecting necks, and the parts that are almost or quite islanded, exclude the idea of equilibrium, whether the system as a whole be stationary or whether it be rotating. In §150, when referring to the fate of nebulous rings, I cited the option of Sir John Herschel to the effect that a nebulous ring would not break at one place and collapse, but would break at many places and form separate masses. I joined with it the opinion of Sir G. B. Airy, to whom I put the question whether these would remain separate, and who agreed that the masses thus formed, parting more widely at some one place, would eventually collapse into a single mass. Parallel conclusions respecting changes in the Milky Way seem legitimate, or rather, indeed, seem necessitated. Separation of it into parts — minor Sidereal Systems — is a result to which its present aspect points. That such minor sidereal systems could remain permanently independent is not to be supposed. Mutual attraction would cause in some cases the formation of binary sidereal systems, and in other cases coalescence, according to the directions and amounts of their respective proper motions. The implication is that there may be repeated, on vaster scales, changes like those described as occurring in star-clusters: local concentrations taking place within these minor sidereal systems, with resulting evolutions and dissolutions, at the same time that the minor sidereal systems themselves, progressively uniting, become more condensed, and consequently the scenes of more active changes of like kinds. If, giving imagination the rein, we suppose this process carried to its limit, and ultimately to present on an immensely larger scale the kind of change which the nubeculae exhibit, there arises the thought of a progressing destruction of the molar motions possessed by the concentrating stars, and a simultaneous diffusion of their substances, which, as the process comes to a close, spreads the matter of the Sidereal System in its nebulous form throughout the whole of that space which it originally filled — a diffusion reversing the preceding concentration — a dissolution that prepares the way for a new evolution. Reduced to its abstract form, the argument is that the quantity of motion implied by dispersion must be as great as the quantity of motion implied by aggregation, or rather must be the same motion, taking now the molar form and now the molecular form; and if we allow ourselves to conceive this as an ultimate result there arises the conception not only of local evolutions and dissolutions throughout our Sidereal System but of general evolutions and dissolutions alternating indefinitely.

But we cannot draw such a conclusion without tacitly assuming something beyond the limits of possible knowledge, namely, that the energy contained in our Sidereal System remains undiminished. Continuance of such alterations without end presupposes that the quantity of molecular motion radiated by each star in the course of its formation from diffused matter, shall either not escape from our Sidereal System or shall be compensated by an equal quantity of molecular motion radiated into it from other parts of space. If the ether which fills the interspaces of our Sidereal System has a boundary somewhere beyond the outermost stars, it is inferable that motion is not lost by radiation beyond that boundary; and if so the original degree of diffusion may be resumed. Or if, supposing that the ether is unbounded, the temperature of space is the same within and without our Sidereal System, then it is inferable that the quantity of motion contained within our Sidereal System remaining undiminished, its alternate concentrations and diffusions may continue undiminished. But we shall never be able to say whether either condition is fulfilled.

We may indeed dismiss such questions as passing the bounds of rational speculation. They have here been touched upon for the purpose of showing that it is not inferable from the general progress towards equilibrium that a state of universal quiescence or death will be reached; but that if a process of reasoning ends in that conclusion, a further process of reasoning points to renewals of activity and life.

Here, however, it is needless for the adequate presentation of the general doctrine, that Evolution and Dissolution should be traced in either direction to their ends. In §93 it was said that no actual philosophy can fill out the scheme of an ideal philosophy — cannot even of a small aggregate trace the entire history from its appearance to its disappearance, and must be immeasurably far from doing this with the all-comprehensive aggregate.

But unable though we must ever remain to give a complete account of the transformation of things, even in any of its minor parts, and still more in its totality we are able to recognize throughout it the same general law; and may reasonably infer that it holds in those parts of the transformation which are beyond the reach of our intelligence as it does in those parts which are within its reach.

Chapter 24

Summary and Conclusion

§184. At the close of a work like this, it is more than usually needful to contemplate as a whole that which the successive chapters have presented in parts. A coherent knowledge implies something more than the establishment of connexions: we must not rest after seeing how each minor group of truths falls into its place within some major group, and how all the major groups fit together. It is requisite that we should retire a space, and, looking at the entire structure from a distance at which details are lost to view, observe its general character.

Something more than recapitulation — something more even than an organized re-statement, will come within the scope of the chapter. We shall find that in their ensemble the general truths reached exhibit, under certain aspects, a oneness not hitherto observed.

There is, too, a special reason for noting how the various divisions and subdivisions of the argument consolidate; namely, that the theory at large thereby obtains a final illustration. The reduction of the generalizations which have been set forth separately to a completely integrated state, exemplifies once more the process of Evolution, and strengthens still further the general fabric of conclusions.

§185. Here, indeed, we find ourselves brought round unexpectedly to the truth with which we set out, and with which our re-survey must commence. For this integrated form of knowledge is the form which, apart from the doctrine of Evolution, we decided to be the highest form.

When we inquired what constitutes Philosophy — when we compared men's various conceptions of Philosophy, so that, eliminating the elements in which they differed, we might see in what they agreed; we found in them all the tacit implication that Philosophy is completely unified knowledge. Apart from each scheme of unified knowledge, and apart from proposed methods by which unification is to be effected, we traced in every case a belief that unification is possible, and that the end of Philosophy is achievement of it.

After reaching this conclusion we considered the data with which Philosophy must set out. Fundamental propositions, or propositions not deducible from deeper ones can be established only by showing the complete congruity of all the results reached through the assumption of them; and, premising that they were simply assumed till thus established, we took as our data those components of our intelligence without which there cannot go on the mental processes implied by philosophizing.

From the specification of these we passed to certain primary truths — "The Indestructibility of Matter," "The Continuity of Motion," and "The Persistence of force;" of which the last is ultimate and the others derivative. Having previously seen that our experiences of Matter and Motion are resolvable into experiences of force, we further saw the truths that Matter and Motion are unchangeable in quantity, to be implications of the truth that Force is unchangeable in quantity. This we concluded is the truth by derivation from which all other truths are to be proved.

The first of the truths which presented itself to be so proved, is "The Persistence of the relations among Forces." This, which is ordinarily called Uniformity of Law, we found to be a necessary implication of the truth that Force can neither arise out of nothing nor lapse into nothing.

The next deduction was that forces which seem to be lost are transformed into their equivalents of other forces; or, conversely, that forces which become manifest, do so by disappearance of pre-existing equivalent forces. These truths we found illustrated by the motions of the heavenly bodies, by the changes going on over the Earth's surface, and by all organic and super-organic actions.

It was shown to be the same with the law that everything moves along the line of least resistance, or the line of greater traction, or their resultant. Among movements of all orders, from those of stars down to those of nervous discharges and commercial currents, it was shown both that this is so, and tat, given the Persistence of Force, it must be so.

So, too, we saw it to be with "The Rhythm Of Motion." All motion alternates — be it the motion of planets in their orbits or ethereal molecules in their undulations be it the cadences of speech or the rises and falls of prices; and, as before, it became manifest that Force being persistent, this perpetual reversal of Motion between limits is inevitable.

§186. These truths holding of existences at large, were recognized as of the kind required to constitute what we distinguish as Philosophy. But, on considering them, we perceived that as they stand they do not form a Philosophy. and that a Philosophy cannot be formed by any number of such truths separately known. Each expresses the law of some one factor by which phenomena, as we experience them, are produced; or, at most, expresses the law of co-operation of some two factors. But knowing what are the elements of a process, is not knowing how these elements combine to effect it. That which alone can unify knowledge must be the law of co-operation of the factors — a law expressing simultaneously the complex antecedents and the complex consequents which any phenomenon as a whole presents.

A further inference was that Philosophy, as we understand it, must not unify the changes displayed in separate concrete phenomena only; and must not stop short with unifying the changes displayed in separate classes of concrete phenomena; but must unify the changes displayed in all concrete phenomena. If the law of operation of each factor holds true throughout the Cosmos, so, too, must the law of their co-operation. And hence in comprehending the Cosmos as conforming to this law of co-operation, must consist that highest unification which Philosophy seeks.

Descending to a more concrete view, we saw that the law sought must be the law of the continuous re-distribution of Matter and Motion. The changes everywhere going on, from those which are slowly altering the structure of our galaxy down to those which constitute a chemical decomposition, are changes in the relative positions of component parts; and everywhere necessarily imply that along with a new arrangement of Matter there has arisen a new arrangement of Motion. Hence it follows that there must be a law of the concomitant redistribution of Matter and Motion which holds of every change, and which, by thus unifying all changes, must be the basis of a Philosophy.

In commencing our search for this universal law of re-distribution, we contemplated from another point of view the problem of Philosophy, and saw that its solution could not but be of the nature indicated. It was shown that an ideally complete Philosophy must formulate the whole series of changes passed through by existences separately and as a whole in passing from the imperceptible to the perceptible and again from the perceptible to the imperceptible. If it begins its explanations with existences that already have concrete forms, or leaves off while they still retain concrete forms, then, manifestly, they had preceding histories, or will have succeeding histories, or both, of which no account is given. Whence we saw it to follow that the formula sought, equally applicable to existences taken singly and in their totality, must be applicable to the whole history of each and to the whole history of all. This must be the ideal form of a Philosophy, however far short of it the reality may fall.

By these considerations we were brought within view of the formula. For if it had to express the entire progress from the imperceptible to the perceptible and from the perceptible to the imperceptible; and if it Was also to express the continuous re-distribution of Matter and Motion, then, obviously, it could be no other than one defining the opposite processes of concentration and diffusion in terms of Matter and Motion. And if so, it must be a statement of the truth that the concentration of Matter implies the dissipation of Motion, and that, conversely, the absorption of Motion implies the diffusion of Matter.

Such, in fact, we found to be the law of the entire cycle of changes passed through by every existence. Moreover we saw that besides applying to the whole history of each existence, it applies to each detail of the history. Both processes are going on at every instant. but always there is a differential result in favour of the first or the second. And every change, even though it be only a transposition of parts, inevitably advances the one process or the other.

Evolution and Dissolution, as we name these opposite transformations, though thus truly defined in their most general characters, are but incompletely defined; or rather, while the definition of Dissolution is sufficient, the definition of Evolution is extremely insufficient. Evolution is always an integration of Matter and dissipation of Motion; but it is in nearly all cases much more than this. The primary re-distribution of Matter and Motion is accompanied by secondary re-distributions.

Distinguishing the different kinds of Evolution thus produced as simple and compound, we went on to consider under what conditions the secondary re-distributions which make Evolution compound, take place. We found that a concentrating aggregate which loses its contained motion rapidly, or integrates quickly, exhibits only simple Evolution; but in proportion as its largeness, or the peculiar constitution of its components, hinders the dissipation of its motion, its parts, while undergoing that primary re-distribution which results in integration, undergo secondary re-distributions producing more or less complexity.

§187. From this conception of Evolution and Dissolution as together making up the entire process through which things pass; and from this conception of Evolution as divided into simple and compound; we went on to consider the law of Evolution, as exhibited among all orders of existences, in general and in detail.

The integration of Matter and concomitant dissipation of Motion, was traced not in each whole only, but in the parts into which each whole divides. By the aggregate Solar System, as well as by each planet and satellite, progressive concentration has been, and is still being, exemplified. In each organism that general incorporation of dispersed materials which causes growth, is accompanied by local incorporations, forming what we call organs. Every society, while it displays the aggregative process by its increasing mass of population, displays it also by the rise of dense masses on special parts of its area. And in all cases, along with these direct integrations there go the indirect integrations by which parts are made mutually dependent.

From this primary re-distribution we were led on to consider the secondary re-distributions, by inquiring how there came to be a formation of parts during the formation of a whole. It turned out that there is habitually a passage from homogeneity to heterogeneity along with the passage from diffusion to concentration. While the matter composing the Solar System has been assuming a denser form, it has changed from unity to variety of distribution. Solidification of the Earth has been accompanied by a progress from comparative uniformity to extreme multiformity. In the course of its advance from a germ to a mass of relatively great bulk, every plant and animal also advances from simplicity to complexity. The increase of a society in numbers and consolidation has for its concomitant an increased heterogeneity both of its political and its industrial organization. And the like holds of all super-organic products — Language, Science, Art, and Literature.

But we saw that these secondary re-distributions are not thus completely expressed. While the parts into which each whole is resolved become more unlike one another, they also become more sharply marked off. The result of the secondary re-distribution is therefore to change an indefinite homogeneity into a definite heterogeneity. This additional trait also we found in evolving aggregates of all orders. Further consideration, however, made it apparent that the increasing definiteness which goes along with increasing heterogeneity is not an independent trait, but that it results from the integration which progresses in each of the differentiating parts, while it progresses in the whole they form.

Further, it was pointed out that in all evolutions, inorganic, organic, and super-organic, this change in the arrangement of Matter is accompanied by a parallel change in the arrangement of contained Motion: every increase in structural complexity involving a corresponding increase in functional complexity. It was shown that along with the integration of molecules into masses, there arises an integration of molecular motion in to the motion of masses; and that as fast as there results variety in the sizes and forms of aggregates and their relations to incident forces, there also results variety in their movements.

The transformation thus contemplated under separate aspects, being in itself but one transformation, it became needful to unite these separate aspects into a single conception — to regard the primary and secondary redistributions as simultaneously working their various effects. Everywhere the change from a confused simplicity to a distinct complexity, in the distribution of both matter and motion, is incidental to the consolidation of the matter and the loss of its internal motion. Hence the re-distribution of the matter and of its retained motion, is from a relatively diffused, uniform, and indeterminate arrangement, to a relatively concentrated, multiform, and determinate arrangement.

§188. We come now to one of the additions that may be made to the general argument while summing it up. Here is the fit occasion for observing a higher degree of unity in the foregoing inductions, than we observed while making them.

The law of Evolution has been thus far contemplated as holding true of each order of existences, considered as a separate order. But the induction as so presented, falls short of that completeness which it gains when we contemplate these several orders of existences as forming together one natural whole. While we think of Evolution as divided into astronomic, geologic, biologic, psychologic, sociologic, etc., it may seem to some extent a coincidence that the same law of metamorphosis holds throughout all its divisions. But when we recognize these divisions as mere conventional groupings, made to facilitate the arrangement and acquisition of knowledge — when we remember that the different existences with which they severally deal are component parts of one Cosmos; we see at once that there are not several kinds of Evolution having certain traits in common, but one Evolution going on everywhere after the same manner, We have repeatedly observed that while any whole is evolving, there is always going on an evolution of the parts into which it divides itself; but we have not observed that this equally holds of the totality of things, which is made up of parts within parts from the greatest down to the smallest. We know that while a physically-cohering aggregate like the human body is getting larger and taking on its general shape, each of its organs is doing the same; that while each organ is growing and becoming unlike others, there is going on a differentiation and integration of its component tissues and vessels; and that even the components of these components are severally increasing and passing into more definitely heterogeneous structures. But we have not duly remarked that while each individual is developing, the society of which he is an insignificant unit is developing too; that while the aggregate mass forming a society is integrating and becoming more definitely heterogeneous, so, too, that total aggregate, the Earth, is continuing to integrate and differentiate; that while the Earth, which in bulk is not a millionth of the Solar System, progresses towards its more concentrated structure, the Solar System similarly progresses.

So understood, Evolution becomes not one in principle only, but one in fact. There are not many metamorphoses similarly carried on, but there is a single metamorphosis universally progressing, wherever the reverse metamorphosis has not set in. In any locality, great or small, where the occupying matter acquires an appreciable individuality, or distinguishableness from other matter, there Evolution goes on; or rather, the acquirement of this appreciable individuality is the commencement of Evolution. And this holds regardless of the size of the aggregate, and regardless of its inclusion in other aggregates.

§189. After making them, we saw that the inductions which, taken together, establish the law of Evolution, do not, so long as they remain inductions, form that whole rightly named Philosophy; nor does even the foregoing, from agreement into identity passage of these inductions suffice to produce the unity sought. For, as was pointed out at the time, to unify the truths thus reached with other truths, they must be deduced from the Persistence of Force. Our next step, therefore, was to show why, Force being persistent, the transformation which Evolution shows us necessarily results.

The first conclusion was, that any finite homogeneous aggregate must lose its homogeneity, through the unequal exposures of its parts to incident forces, and that the imperfectly homogeneous must lapse into the decidedly non-homogeneous. It was pointed out that the production of diversities of structure by diverse forces, and forces acting under diverse conditions, has been illustrated in astronomic evolution; and that a like connexion of cause and effect is seen in the large and small modifications undergone by our globe. The early changes of organic germs supplied further evidence that unlikenesses of structure follow unlikenesses of relations to surrounding agencies — evidence enforced by the tendency of the differently-placed members of each species to diverge into varieties. And we found that the contrasts, political and industrial, which arise between the parts of societies, serve to illustrate the same principle. The instability of the relatively homogeneous thus everywhere exemplified, we saw also holds in each of the distinguishable parts into which any whole lapses; and that so the less heterogeneous tends continually to become more heterogeneous.

A further step in the inquiry disclosed a secondary cause of increasing multiformity. Every differentiated part is not simply a seat of further differentiations, but also a parent of further differentiations; since in growing unlike other parts, it becomes a centre of unlike reactions on incident forces, and by so adding to the diversity of forces at work, adds to the diversity of effects produced. This multiplication of effects proved to be similarly traceable throughout all Nature — in the actions and reactions that go on throughout the Solar System, in the never-ceasing geologic complications, in the involved changes produced in organisms by new influences, in the many thoughts and feelings generated by single impressions, and in the ever-ramifying results of each additional agency brought to bear on a society. To which was joined the corollary that the multiplication of effects advances in a geometrical progression along with advancing heterogeneity.

Completely to interpret the structural changes constituting Evolution, there remained to assign a reason for that increasingly-distinct demarcation of parts, which accompanies the production of differences among parts. This reason we discovered to be the segregation of mixed units under the action of forces capable of moving them. We saw that when unlike incident forces have made the parts of an aggregate unlike in the natures of their component units, there necessarily arises a tendency to separation of the dissimilar units from one another, and to a clustering of those units which are similar. This cause of the definiteness of the local integrations which accompany local differentiations, turned out to be likewise exemplified by all kinds of Evolution — by the formation of celestial bodies, by the moulding of the Earth's crust, by organic modifications, by the establishment of mental distinctions, by the genesis of social divisions.

At length, to the query whether these processes have any limit, there came the answer that they must end in equilibrium. That continual division and subdivision of forces which changes the uniform into the multiform and the multiform into the more multiform, is a process by which forces are perpetually dissipated; and dissipation of them, continuing as long as there remain any forces unbalanced by opposing forces, must end in rest. It was shown that when, as happens in aggregates of various orders, many movements go on together, the earlier dispersion of the smaller and more resisted movements, establishes moving equilibria of different kinds: forming transitional stages on the way to complete equilibrium. And further inquiry made it apparent that for the same reason, these moving equilibria have certain self-conserving powers; shown in the neutralization of perturbations, and in the adjustment to new conditions. This general principle of equilibration, like the preceding general principles, was traced throughout all forms of Evolution — astronomic, geologic, biologic, mental, and social. And our concluding inference was, that the penultimate stage of equilibration in the organic world, in which the extremest multiformity and most complex moving equilibrium are established, must be one implying the highest state of humanity.

But the fact which here chiefly concerts us, is that each of these laws of the re-distribution of Matter and Motion, was found to be a derivative law-a law deducible from the fundamental law. The Persistence of Force being granted, there follow as inevitable inferences "The Instability of the Homogeneous" and "The Multiplication of Effects;" while "Segregation" and "Equilibration" also become corollaries. And on thus discovering that the processes of change grouped under these titles are so many different aspects of one transformation, determined by an ultimate necessity we arrive at a complete unification of them — a synthesis in which Evolution in general and in detail becomes known as an implication of the law that transcends proof. Moreover, in becoming thus unified with one another the complex truths of Evolution become simultaneously unified with those simpler truth