It was pointed out that the production of diversities of structure by diverseforces, and forces acting under diverse conditions, has been illustratedin astronomic evolution; and that a like connexion of cause and effect isseen in the large and small modifications undergone by our globe. The earlychanges of organic germs supplied further evidence that unlikenesses of structurefollow unlikenesses of relations to surrounding agencies -- evidence enforcedby the tendency of the differently-placed members of each species to divergeinto varieties. And we found that the contrasts, political and industrial,which arise between the parts of societies, serve to illustrate the sameprinciple. The instability of the relatively homogeneous thus everywhereexemplified, we saw also holds in each of the distinguishable parts intowhich any whole lapses; and that so the less heterogeneous tends continuallyto become more heterogeneous.
A further step in the inquiry disclosed a secondary cause of increasingmultiformity. Every differentiated part is not simply a seat of further differentiations,but also a parent of further differentiations; since in growing unlike otherparts, it becomes a centre of unlike reactions on incident forces, and byso adding to the diversity of forces at work, adds to the diversity of effectsproduced. This multiplication of effects proved to be similarly traceablethroughout all Nature -- in the actions and reactions that go on throughoutthe Solar System, in the never-ceasing geologic complications, in the involvedchanges produced in organisms by new influences, in the many thoughts andfeelings generated by single impressions, and in the ever-ramifying resultsof each additional agency brought to bear on a society. To which was joinedthe corollary that the multiplication of effects advances in a geometricalprogression along with advancing heterogeneity.
Completely to interpret the structural changes constituting Evolution,there remained to assign a reason for that increasingly-distinct demarcationof parts, which accompanies the production of differences among parts. Thisreason we discovered to be the segregation of mixed units under the actionof forces capable of moving them. We saw that when unlike incident forceshave made the parts of an aggregate unlike in the natures of their componentunits, there necessarily arises a tendency to separation of the dissimilarunits from one another, and to a clustering of those units which are similar.
This cause of the definiteness of the local integrations which accompanylocal differentiations, turned out to be likewise exemplified by all kindsof Evolution -- by the formation of celestial bodies, by the moulding ofthe Earth's crust, by organic modifications, by the establishment of mentaldistinctions, by the genesis of social divisions.
At length, to the query whether these processes have any limit, therecame the answer that they must end in equilibrium. That continual divisionand subdivision of forces which changes the uniform into the multiform andthe multiform into the more multiform, is a process by which forces are perpetuallydissipated; and dissipation of them, continuing as long as there remain anyforces unbalanced by opposing forces, must end in rest. It was shown thatwhen, as happens in aggregates of various orders, many movements go on together,the earlier dispersion of the smaller and more resisted movements, establishesmoving equilibria of different kinds: forming transitional stages on theway to complete equilibrium. And further inquiry made it apparent that forthe same reason, these moving equilibria have certain self-conserving powers;shown in the neutralization of perturbations, and in the adjustment to newconditions. This general principle of equilibration, like the preceding generalprinciples, was traced throughout all forms of Evolution -- astronomic, geologic,biologic, mental, and social. And our concluding inference was, that thepenultimate stage of equilibration in the organic world, in which the extremestmultiformity and most complex moving equilibrium are established, must beone implying the highest state of humanity.
But the fact which here chiefly concerts us, is that each of these lawsof the re-distribution of Matter and Motion, was found to be a derivativelaw-a law deducible from the fundamental law. The Persistence of Force beinggranted, there follow as inevitable inferences "The Instability of theHomogeneous" and "The Multiplication of Effects;" while "Segregation"and "Equilibration" also become corollaries. And on thus discoveringthat the processes of change grouped under these titles are so many differentaspects of one transformation, determined by an ultimate necessity we arriveat a complete unification of them -- a synthesis in which Evolution in generaland in detail becomes known as an implication of the law that transcendsproof. Moreover, in becoming thus unified with one another the complex truthsof Evolution become simultaneously unified with those simpler truths shownto have a like origin -- the equivalence of transformed forces, the movementof every mass and molecule along its line of least resistance, and the limitationof its motion by rhythm. Which further unification brings us to a conceptionof the entire plexus of changes presented by each concrete phenomenon, andby the aggregate of concrete phenomena, as a manifestation of one fundamentalfact -- a fact shown alike in the total change and in all the separate changescomposing it. §190. Finally we turned to contemplate, as exhibited throughout Nature,that process of Dissolution which forms the complement of Evolution, andwhich, at some time or other, undoes what Evolution has done.
