oscillations between an extreme in which the subjects are under rigid restraint, and an extreme in which the restraint is not enough to prevent disorder. 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 all bonds. In this familiar fact, that a period of tyranny is followed by a period of license and _vice versâ_, we see how these opposing forces are ever equilibrating each other; and we also see, in the tendency of such movements and counter-movements to become more moderate, how the equilibration progresses towards completeness. 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. This process, now so far advanced among ourselves that the oscillations are comparatively unobtrusive, must go on till the balance between the antagonist forces approaches indefinitely near perfection. For, as we have already seen, the adaptation of man’s nature to the conditions of his existence, cannot cease until the internal forces which we know as feelings are in equilibrium with the external forces they encounter. And the establishment of this equilibrium, is the arrival at a state of human nature and social organization, such that the individual has no desires but those which may be satisfied without exceeding his proper sphere of action, while society maintains no restraints but those which the individual voluntarily respects. The progressive extension of the liberty of citizens, and the reciprocal removal of political restrictions, are the steps by which we advance towards this state. And the ultimate abolition of all limits to the freedom of each, save those imposed by the like freedom of all, must result from the complete equilibration between man’s desires and the conduct necessitated by surrounding conditions.
Of course in this case, as in the preceding ones, there is thus involved a limit to the increase of heterogeneity. A few pages back, we reached the conclusion that each advance in mental evolution, is the establishment of some further internal action, corresponding to some further external action—some additional connection of ideas or feelings, answering to some before unknown or unantagonized connection of phenomena. 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. Whence we saw it to follow that increase of heterogeneity can come to an end only as equilibration is completed. Evidently the like must simultaneously take place with society. Each increment of heterogeneity in the individual, must directly or indirectly involve, as cause or consequence, some increment of heterogeneity in the arrangements of the aggregate of individuals. And the limit to social complexity can be arrived at, only with the establishment of the equilibrium, just described, between social and individual forces.
* * * * * * * * * * § 136. Here presents itself a final question, which has probably been taking a more or less distinct 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—if equilibration, passing through the gradually-perfected forms of moving equilibrium, must end in complete rest; what is the fate towards which all things tend? If the bodies constituting our Solar System are slowly dissipating the forces they possess—if the Sun is losing his heat at a rate which, though insignificant as stated in terms of our chronology, will tell in millions of years—if geologic and meteorologic processes cannot but diminish in activity as the Sun’s radiations diminish—if with the diminution of these radiations there must also go on a diminution in the quantity of vegetal and animal existence—if Man and Society, however high the degree of evolution at which they arrive, are similarly dependent on this supply of force that is gradually coming to an end—if thus the highest, equally with the lowest, terrestrial life, must eventually dwindle and disappear; are we not manifestly progressing towards omnipresent death? And have we thus to contemplate, as the out-come of things, a universe of extinct suns round which circle planets devoid of life?”
That such a state must be the proximate end of the processes everywhere going on, seems beyond doubt. But the further question tacitly involved, whether this state will continue eternally, is quite a different one. To give a positive answer to this further question would be quite illegitimate; since to affirm any proposition into which unlimited time enters as one of the terms, is to affirm a proposition of which one term cannot be represented in consciousness—is to affirm an unthinkable proposition. At a first glance it may appear that the reverse conclusion must be equally illegitimate; and that so the question is altogether insoluble. But further consideration will show that this is not true. So long as the terms to which we confine our reasonings are finite, the finite conclusions reached are not necessarily illegitimate. Though, if the general argument, when carried out, left no apparent escape from the inference that the state of rest to which Evolution is carrying things, must, when arrived at, last for ever, this inference would be invalid, as transcending the scope of human intelligence; yet if, on pushing further the general argument, we bring out the inference that such a state will not last for ever, this inference is not necessarily invalid: since, by the hypothesis, it contains no terms necessarily transcending the scope of human intelligence. It is permissible therefore, to inquire, what are the probable ulterior results of this process which must bring Evolution to a close in Universal Death. Without being so rash as to form anything like a positive conclusion on a matter so vast and so far beyond the boundaries of exact science; we may still inquire what _seems_ to be the remote future towards which the facts point.
It has been already shown that all equilibration, so far as we can trace it, is relative. The dissipation of a body’s motion by communication of it to surrounding matter, solid, liquid, gaseous, and ethereal, tends to bring the body to a fixed position in relation to the matter that abstracts its motion. But all its other motions continue as before. The arrest of a cannon-shot does not diminish its movement towards the East at a thousand miles an hour, along with the wall it has struck; and a gradual dispersion of the Earth’s rotatory motion, would abstract nothing from the million and a half miles per day through which the Earth speeds in its orbit. Further, we have to bear in mind that this motion, the disappearance of which causes relative equilibration, is not lost but simply transferred; and by continual division and subdivision finally reduced to ethereal undulations and radiated through space. Whether the sensible motion dissipated during relative equilibration, is directly transformed into insensible motion, as happens in the case of the Sun; or whether, as in the sensible motions going on around us, it is directly transformed into smaller sensible motions, and these into still smaller, until they become insensible, matters not. In every instance the ultimate result is, that whatever motion of masses is lost, re-appears as molecular motion pervading space. Thus the questions we have to consider, are—Whether after the completion of all the relative equilibrations above contemplated as bringing Evolution to a close, there remain any further equilibrations to be effected?—Whether there are any other motions of masses that must eventually be transformed into molecular motion?—And if there are such other motions, what must be the consequence when the molecular motion generated by their transformation, is added to that which already exists?
To the first of these questions the answer is, that there _do_ remain motions which are undiminished by all the relative equilibrations thus far considered; namely, the motions of translation possessed by those vast masses of incandescent matter called stars—masses now known to be suns that are in all probability, like our own, surrounded by circling groups of planets. The belief that the stars are literally fixed, has long since been exploded: observation has proved many of them to have sensible proper motions. Moreover, it has been ascertained by measurement, that in relation to the stars nearest to us, our own star is moving at the rate of about half a million miles per day; and if, as is admitted to be not improbable by sundry astronomers, our own star is traversing space in the same direction with adjacent stars, its absolute velocity may be, and most likely is, immensely greater than this. Now no such changes as those taking place within the Solar System, even when carried to the extent of integrating the whole of its matter into one mass, and diffusing all its relative movements in an insensible form through space, can affect these sidereal movements. Hence, there appears no alternative but to infer, that these sidereal movements must remain to be equilibrated by some subsequent process.
The next question that arises, if we venture to inquire the probable nature of this process, is—To what law do sidereal motions conform? And to this question Astronomy replies—the law of gravitation. The relative motions of binary stars have proved this. When it was discovered that certain of the double stars are not optically double but physically double, and move round each other, it was at once suspected that their revolutions might be regulated by a mutual attraction like that which regulates the revolutions of planets and satellites. The requisite measurements having been from time to time made, the periodic times of sundry binary stars were calculated on this assumption; and the subsequent performances of their revolutions in the predicted periods, have completely verified the assumption. If, then, it is demonstrated that these remote bodies are centres of gravitation—if we infer that all other stars are centres of gravitation, as we may fairly do—and if we draw the unavoidable corollary, that this gravitative force which so conspicuously affects stars that are comparatively near each other, must affect remote stars; we find ourselves led to the conclusion that all the members of our Sidereal System gravitate, individually and as an aggregate.
But if these widely-dispersed moving masses mutually gravitate, what must happen? There appears but one tenable answer. Even supposing they were all absolutely equal in weight, and arranged into an annulus with absolute regularity, and endowed with exactly the amounts of centrifugal force required to prevent nearer approach to their common centre of gravity; the condition would still be one which the slightest disturbing force would destroy. Much more then are we driven to the inference, that our actual Sidereal System cannot preserve its present arrangement: the irregularities of its distribution being such as to render even a temporary moving equilibrium impossible. If the stars are so many centres of an attractive force that varies inversely as the square of the distance, there appears to be no escape from the conclusion, that the structure of our galaxy must be undergoing change; and must continue to undergo change.
Thus, in the absence of tenable alternatives, we are brought to the positions:—1, that the stars are in motion;—2, that they move in conformity with the law of gravitation;—3, that, distributed as they are, they cannot move in conformity with the law of gravitation, without undergoing change of arrangement. If now we permit ourselves to take a further step, and ask the nature of this change of arrangement, we find ourselves obliged to infer a progressive concentration. Whether we do or do not suppose the clustering which is now visible, to have been caused by mutual gravitation acting throughout past eras, as the hypothesis of Evolution implies, we are equally compelled to conclude that this clustering must increase throughout future eras. Stars at present dispersed, must become locally aggregated; existing aggregations, at the same time that they are enlarged by the drawing in of adjacent stars, must grow more dense; and aggregations must coalesce with each other: each greater degree of concentration augmenting the force by which further concentration is produced.
And now what must be the limit of this concentration? The mutual attraction of two individual stars, when it so far predominates over other attractions as to cause approximation, almost certainly ends in the formation of a binary star; since the motions generated by other attractions, prevent the two stars from moving in straight lines to their common centre of gravity. Between small clusters, too, having also certain proper motions as clusters, mutual attraction may lead, not to complete union, but to the formation of binary clusters. As the process continues however, and the clusters become larger, it seems clear that they must move more directly towards each other, thus forming clusters of increasing density; and that eventually all clusters must unite into one comparatively close aggregation. While, therefore, during the earlier stages of concentration, the probabilities are immense against the actual contact of these mutually-gravitating masses; it is tolerably manifest, that as the concentration increases, collision must become probable, and ultimately certain. This is an inference not lacking the support of high authority. Sir John Herschel, treating of those numerous and variously-aggregated clusters of stars revealed by the telescope, and citing with apparent approval his father’s opinion, that the more diffused and irregular of these, are “globular clusters in a less advanced state of condensation;” subsequently remarks, that “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.” Now what is here alleged of these minor sidereal aggregations, cannot be denied of the large aggregations; and thus the above-described process of concentration, appears certain to bring about an increasingly-frequent integration of masses.
We have next to consider the consequences of the accompanying loss of velocity. The sensible motion which disappears, cannot be destroyed; but must be transformed into insensible motion. What will be the effect of this insensible motion? Some approach to a conception of it, will be made by considering what would happen were the comparatively insignificant motion of our planet thus transformed. 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 so relatively small a momentum as that acquired by the Earth in falling through 95,000,000 of miles to the Sun, being equivalent to a molecular motion such as would reduce the Earth to gases of extreme rarity; what must be the molecular motion generated by the mutually-arrested momenta of two stars, that have moved to their common centre of gravity through spaces immeasurably greater? There seems no alternative but to conclude, that this molecular motion must be so great, as to reduce the matter of the stars to an almost inconceivable tenuity—a tenuity like that which we ascribe to nebular matter. Such being the immediate effect of the integration of any two stars in a concentrating aggregate, what must be the ulterior effect on the aggregate as a whole? Sir John Herschel, in the passage above quoted, describing the collisions that must arise in a mutually-gravitating group of stars, adds that those stars “which remain outstanding after such conflicts, _must_ ultimately give rise to circulation of a permanent character.” The problem, however, is here dealt with purely as a mechanical one: the assumption being, that the mutually-arrested masses will continue as masses—an assumption to which no objection was apparent at the time when Sir John Herschel wrote this passage; since the doctrine of the correlation of forces was not then recognized. But obliged as we now are to conclude, that stars moving at the high velocities acquired during concentration, will, by mutual arrest, be dissipated into gases of great tenuity, the problem becomes different; and a different inference appears unavoidable. For the diffused matter produced by such conflicts, must form a resisting medium, occupying that central region of the aggregate 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 further such collision, by augmenting this resisting medium, and making the losses of velocity greater, must further 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 and extending beyond the whole aggregate, must, by continuing to shorten their gyrations, entail an increasingly-active integration and re-active disintegration of the moving masses; until they are all finally dissipated. This, indeed, is the conclusion which, leaving out all consideration of the process gone through, presents itself as a simple deduction from the persistence of force. If the stars have been, and still are, concentrating however indirectly on their common centre of gravity, and must eventually reach it; it is a corollary from the persistence of force, that the quantities of motion they have severally acquired, must suffice to carry them away from the common centre of gravity to those remote regions whence they originally began to move towards it. And since, by the conditions of the case, they cannot return to these remote regions in the shape of concrete masses, they must return in the shape of diffused masses. Action and reaction being equal and opposite, the momentum producing dispersion, must be as great as the momentum acquired by aggregation; and being spread over the same quantity of matter, must cause an equivalent distribution through space, whatever be the form of the matter. One condition, however, essential to the literal fulfilment of this result, must be specified; namely, that the quantity of molecular motion produced and radiated into space by each star in the course of its formation from diffused matter, shall be compensated by an equal quantity of molecular motion radiated from other parts of space into the space which our Sidereal System occupies. In other words, if we set out with that amount of molecular motion implied by the existence of the matter of our Sidereal System in a nebulous form; then it follows from the persistence of force, that if this matter undergoes the re-distribution constituting Evolution, the quantity of molecular motion given out during the integration of each mass, plus the quantity of molecular motion given out during the integration of all the masses, must suffice again to reduce it to the same nebulous form. Here indeed we arrive at an impassable limit to our reasonings; since we cannot know whether this condition is or is not fulfilled. On the hypothesis of an unlimited space, containing, at certain intervals, Sidereal Systems like our own, it may be that the quantity of molecular motion radiated into the region occupied by our Sidereal System, is equal to that which our Sidereal System radiates; in which case the quantity of motion possessed by it, remaining undiminished, our Sidereal System may continue during unlimited time, to repeat this alternate concentration and diffusion. But if, on the other hand, throughout boundless space there exist no other Sidereal Systems subject to like changes, or if such other Sidereal Systems exist at more than a certain average distance from each other; then it seems an unavoidable conclusion that the quantity of motion possessed, must diminish by radiation into unoccupied space; and that so, on each successive resumption of the nebulous form, the matter of our Sidereal System will occupy a less space; until at the end of an infinite time it reaches either a state in which its concentrations and diffusions are relatively small, or a state of complete aggregation and rest. Since, however, we have no evidence showing the existence or non-existence of Sidereal Systems throughout remote space; and since, even had we such evidence, a legitimate conclusion could not be drawn from premises of which one element (unlimited space) is inconceivable; we must be for ever without answer to this transcendent question. All we can say is, that so far as the data enable us to judge, the integration of our Sidereal System will be followed by disintegration; that such integration and disintegration will be repeated; and that, for anything we know to the contrary, the alternation of them may continue without limit.
But leaving this ultimate insoluble problem, and confining ourselves to the proximate and not necessarily insoluble one, we find reason for thinking that after the completion of those various equilibrations which bring to a close all the forms of Evolution we have contemplated, there must still continue an equilibration of a far wider kind. When that integration everywhere in progress throughout our Solar System, has reached its climax, there will remain to be effected the immeasurably greater integration of our Solar System, with all other such systems. As in those minor forms now going on around us, this integration with its concomitant equilibration, involves the change of aggregate motion into diffused motion; so in those vaster forms hereafter to be carried out, there must similarly be gained in molecular motion what is lost in the motion of masses; and the inevitable transformation of this motion of masses into molecular motion, cannot take place without reducing the masses to a nebulous form. Thus we seem led to the conclusion that the entire process of things, as displayed in the aggregate of the visible Universe, is analogous to the entire process of things as displayed in the smallest aggregates. Where, as in organic bodies, the whole series of changes constituting Evolution can be traced, we saw that, dynamically considered, Evolution is a change from molecular motion to the motion of masses; and this change, becoming more active during the ascending phase of Evolution while the masses increase in bulk and heterogeneity, eventually begins to get less active; until, passing through stages in which the integration grows greater, and the equilibrium more definite, it finally ceases; whereupon there arises, by an ulterior process, an increase of molecular motion, ending in the more or less complete dissolution of the aggregate. And here we find reason to believe that, along with each of the thousands of similar ones dispersed through the heavens, our Solar System, after passing through stages during which the motion of masses is produced at the expense of lost molecular motion, and during which there goes on an increasingly active differentiation and integration, arrives at a climax whence these changes, beginning to decline in activity, slowly bring about that complete integration and equilibration which in other cases we call death; and that there afterwards comes a time, when the still-remaining motions of masses are transformed into a molecular motion which causes dissolution of the masses. Motion as well as Matter being fixed in quantity, it would seem that the change in the distribution of Matter which Motion effects, coming to a limit in whichever direction it is carried, the indestructible Motion thereupon necessitates a reverse distribution. Apparently, the universally-coexistent forces of attraction and repulsion, which, as we have seen, necessitate rhythm in all minor changes throughout the Universe, also necessitate rhythm in the totality of its changes—produce now an immeasurable period during which the attractive forces predominating, cause universal concentration, and then an immeasurable period during which the repulsive forces predominating, cause universal diffusion—alternate eras of Evolution and Dissolution. And thus there is suggested the conception of a past during which there have been successive Evolutions similar to that which is now going on; and a future during which successive other such Evolutions may go on.
Let none suppose, however, that this is to be taken as anything more than a speculation. In dealing with times and spaces and forces so immensely transcending those of which we have definite experience, we are in danger of passing the limits to human intelligence. Though these times and spaces and forces cannot literally be classed as infinite; yet they are so utterly beyond the possibility of definite conception, as to be almost equally unthinkable with the infinite. What has been above said, should therefore be regarded simply as a possible answer to a possible doubt. When, 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, the Universal Death thus implied will continue indefinitely; it is legitimate to point out how, on carrying the argument still further, we are led to infer a subsequent Universal Life. But while this last inference may fitly be accepted as a demurrer to the first, it would be unwise to accept it in any more positive sense.
* * * * * * * * * * § 137. Returning from this parenthetical discussion, concerning the probable or possible state of things that may arise after Evolution has run its course; and confining ourselves to the changes constituting Evolution, with which alone we are immediately concerned; we have now to inquire whether the cessation of these changes, in common with all their transitional characteristics, admits of _à priori_ proof. It will soon become apparent that equilibration, not less than the preceding general principles, is deducible from the persistence of force.
We have seen (§ 85) that phenomena are interpretable only as the results of universally-coexistent forces of attraction and repulsion. These universally-coexistent forces of attraction and repulsion, are, indeed, the complementary aspects of that absolutely persistent force which is the ultimate datum of consciousness. Just in the same way that the equality of action and re-action is a corollary from the persistence of force, since their inequality would imply the disappearance of the differential force into nothing, or its appearance out of nothing; so, we cannot become conscious of an attractive force without becoming simultaneously conscious of an equal and opposite repulsive force. For every experience of a muscular tension, (under which form alone we can immediately know an attractive force,) presupposes an equivalent resistance—a resistance shown in the counter-balancing pressure of the body against neighbouring objects, or in that absorption of force which gives motion to the body, or in both—a resistance which we cannot conceive as other than equal to the tension, without conceiving force to have either appeared or disappeared, and so denying the persistence of force. And from this necessary correlation, results our inability, before pointed out, of interpreting any phenomena save in terms of these correlatives—an inability shown alike in the compulsion we are under to think of the statical forces which tangible matter displays, as due to the attraction and repulsion of its atoms, and in the compulsion we are under to think of dynamical forces exercised through space, by regarding space as filled with atoms similarly endowed. Thus from the existence of a force that is for ever unchangeable in quantity, there follows, as a necessary corollary, the co-extensive existence of these opposite forms of force—forms under which the conditions of our consciousness oblige us to represent that absolute force which transcends our knowledge.
But the forces of attraction and repulsion being universally co-existent, it follows, as before shown, that all motion is motion under resistance. Units of matter, solid, liquid, aëriform, or ethereal, filling the space which any moving body traverses, offer to such body the resistance consequent on their cohesion, or their inertia, or both. In other words, the denser or rarer medium which occupies the places from moment to moment passed through by such moving body, having to be expelled from them, as much motion is abstracted from the moving body as is given to the medium in expelling it from these places. This being the condition under which all motion occurs, two corollaries result. The first is, that the deductions perpetually made by the communication of motion to the resisting medium, 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 till equilibration takes place; and equilibration must eventually take place. Both these are manifest deductions from the persistence of force. To say that the whole or part of a body’s motion can disappear, save by transfer to something which resists its motion, is to say that the whole or part of its motion can disappear without effect; which is to deny the persistence of force. Conversely, to say that the medium traversed can be moved out of the body’s path, without deducting from the body’s motion, is to say that motion of the medium can arise out of nothing; which is to deny the persistence of force. Hence this primordial truth is our immediate warrant for the conclusions, that the changes which Evolution presents, cannot end until equilibrium is reached; and that equilibrium must at last be reached.