expressions. This inability to maintain a balance in the use of verbal symbols, which characterizes every man, characterizes, by consequence, aggregates of men; and the desynonymization of words is the ultimate effect.
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.
* * * * * § 114. 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 two heads.
A business partnership, balanced as the authorities of its members may theoretically be, practically 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 usually 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 the 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 manifestly 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 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 school-boys. 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 it is abundantly clear that an aggregation of men, absolutely alike in their endowments, would eventually undergo a similar transformation. For in the absence of perfect 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 finally initiate social differentiations. Even inequalities of health caused by accidents, must, by entailing inequalities of physical and mental power, disturb the exact balance of mutual influences among the units; and the balance once disturbed, must inevitably be lost. Whence, indeed, besides seeing that a body of men absolutely homogeneous in their governmental relations, must, like all other homogeneous bodies, become heterogeneous, we also see that it must do this from the same ultimate cause—unequal exposure of its parts to incident forces.
The first industrial divisions of societies are much more obviously 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 economical differentiations. But a community which, growing populous, 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 physical 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 periodical assemblage, become traders, and a town springs up. Each of these classes undergoes a modification of character consequent on its function, and better fitting it to its function. Later in the process of social evolution these local adaptations are greatly multiplied. A result of differences in soil and climate, is that the rural inhabitants in different parts of the kingdom have their occupations partially specialized; and become respectively distinguished as chiefly producing cattle, or sheep, or wheat, or oats, or hops, or cyder. People living where coal-fields are discovered are transformed into colliers; Cornishmen take to mining because Cornwall is metalliferous; and the iron-manufacture is the dominant industry where ironstone is plentiful. Liverpool has assumed the office of importing cotton, in consequence 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. Even in the establishment of breweries, of dye-works, of slate-quarries, of brickyards, we may see the same truth. So that both in general and in detail, the specializations of the social organism which characterize separate districts, primarily depend on local circumstances. Those divisions of labour which under another aspect were interpreted as due to the setting up of motion in the directions of least resistance (§ 91), 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 case _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 course of human action in those localities—entails industrial differentiations.
* * * * * § 115. In common with the general truths set forth in preceding chapters, the instability of the homogeneous is demonstrable _à priori_. It, like each of them, is a corollary from the persistence of force. Already this has been tacitly implied by assigning unlikeness in the exposure of its part to surrounding agencies, as the reason why a uniform mass loses its uniformity. But here it will be proper to expand this 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 with which the striking body comes in contact, receiving the whole of the communicated momentum, is driven in towards the centre of the mass. It thus compresses and tends to displace the more centrally situated portions of the mass. These, however, cannot be compressed or thrust out of their places without pressing on all surrounding portions. And when the blow is violent enough to fracture the mass, we see, in the radial dispersion of its fragments, that the original momentum, in being distributed throughout it, has been divided into numerous minor momenta, unlike in their directions. We see that these directions are determined by the positions of the parts with respect to each other, and with respect to the point of impact. 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 cause 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. Taking the simplest case (that of a sphere) we see that 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°. Again, the molecular vibrations propagated through the mass from the surface which receives the heat, must proceed inwards at angles differing for each point. Further, the interior parts of the sphere affected 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 atoms are all thrown into states of vibration more or less unlike each other.
But now, what is the ultimate meaning of the conclusion that a uniform 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, of molecular motion, &c. 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 directions, the effects produced on these two parts by like forces must be different in their directions. Why must they be different? They must 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 very unequal. The outer parts of masses are usually alone exposed to chemical actions; and not only are their inner parts shielded from the affinities of external elements, but such affinities are brought to bear unequally on their surfaces; since chemical action sets up currents through the medium in which it takes place, and so brings to the various parts of the surface unequal quantities of the active agent. Again, 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. But to say the different parts of an aggregate receive different quantities of any incident force, is to say that their states are modified by it in different degrees—is to say that if they were before homogeneous in their relations 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. We may, by parallel reasoning, reach the conclusion that, 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 each other. 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. 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 the various positions of the parts in relation to any incident force, preventing them from receiving it in uniform amounts and directions, a further difference in the effects wrought on them is inevitably produced.
One further remark is needed. To the conclusion that the changes with which Evolution _commences_, are thus necessitated, remains to be added the conclusion that these changes must _continue_. The absolutely homogeneous 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 which characterize 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.
----- Footnote 16: The idea developed in this chapter originally formed part of an article on “Transcendental Physiology,” published in 1857. See _Essays_, pp. 279–290.
CHAPTER XIV. THE MULTIPLICATION OF EFFECTS.
§ 116. 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.
When a uniform aggregate is subject to a uniform force, we have seen that its constituents, being differently conditioned, are differently modified. But while we have contemplated the various parts of the aggregate as thus 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 and important as the others. Action and re-action being equal and opposite, it follows that 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.
A single force is divided by conflict with matter into forces that widely diverge. 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. These being reflected at all angles from the Moon’s surface, some few of them strike the Earth. By a like process the few which reach the Earth are again diffused through surrounding space. And on each occasion, such portions of the rays as are absorbed instead of reflected, undergo refractions that equally destroy their parallelism. More than this is true. By conflict with matter, a uniform force is in part changed into forces differing in their directions; and in part it is 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 a moment’s thought shows that this is a very incomplete view of the matter. Besides the visible mechanical result, sound is produced; or, to speak accurately, 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, but 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 disengagement of heat. In some cases a spark—that is, light—results, from the incandescence of a portion struck off; and occasionally this incandescence is associated with chemical combination. Thus, by the original mechanical force expended in the collision, at least five, and often more, different 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 carbonic acid, water, &c.—in itself a result more complex than the extraneous heat that first caused it. But along with this process of combination there is a production of heat; there is a production of light; there is an ascending column of hot gases generated; there are currents established 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 carbonic acid formed, will by and by 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 come 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 it warms. The light, falling on various substances, calls forth from them reactions by which it is modified; and so divers colours are produced. Similarly even 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—a uniform force thus reduced to a multiform force—becomes the cause of a secondary increase of multiformity in the body which decomposes it. In the last chapter we saw that the several parts of an aggregate are differently modified by any incident force. It has just been shown that by the reactions of the differently modified parts, the incident force itself must be divided into differently modified parts. Here it remains to point out that 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 into 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, as well as the degree of their unlikeness, is an important factor in the process. Every additional specialized division is an additional centre of specialized forces. If a uniform whole, in being itself made multiform by an incident force, makes the incident force multiform; if a whole consisting of two unlike sections, divides an incident force into two unlike groups of multiform forces; it is clear that each new unlike section 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. Each stage of evolution must initiate a higher stage.
* * * * * § 117. The force of aggregation acting on irregular masses of rare matter, diffused through a resisting medium, will not cause such masses to move in straight lines to their common centre of gravity; but, as before said, each will take a curvilinear path, directed to one or other side of the centre of gravity. All of them being differently conditioned, gravitation will impress on each a motion differing in direction, in velocity, and in the degree of its curvature—uniform aggregative force will be differentiated into multiform momenta. The process thus commenced, must go on till it produces a single mass of nebulous matter; and these independent curvilinear motions must result in a movement of this mass round its axis: a simultaneous condensation and rotation in which we see how two effects of the aggregative force, at first but slightly divergent, become at last widely differentiated. A gradual increase of oblateness in this revolving 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, which must accompany 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 sufficiently 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 alone suffice our purpose. Consider first the effects of its momentum round its axis. 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 aërial 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 differences of the seasons, both simultaneous and successive, which pervade its surface, are thus caused. External attraction acting on this rotating oblate 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, &c. 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 continually. Thus the force exercised by any planet works a different effect on each of the rest; this different effect is from each as a centre partially broken up into minor different effects on the rest; and so on in ever multiplying and diminishing waves throughout the entire system.
* * * * * § 118. 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 must 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, &c., have been already noticed—and I here 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