2. End suggested by this tendency to variation
2. "The lower animals," says a writer on biology, "are just as well organised for the purposes of their life as the higher are for theirs. The tape-worm is relatively quite as perfect as the man, and distinguished from him by many superior capabilities."[227] It is incorrect to look upon the evolution of animal life as working upon one line, so that the different kinds of living beings can be arranged, as it were, in an order of merit, in which the organisation of the higher animal plainly excels that of the lower. The conditions of life are manifold and various enough to permit of the existence of many species equally perfect in relation to their environments. The fact that we are still able to speak of one species or one animal as higher than another, is not owing to the one being better adapted to its environment than the other, but is supposed rather to be due to the higher forms having "their organs more distinctly specialised for different functions."[228] Even Mr Spencer, for whom equilibrium is the goal of life, implicitly admits that "adaptation" alone is not the end of human action, by his doctrine that the degree of evolution may be measured by the complexity of the adjustments it effects between organism and environment. |(a) prescribes self-development rather than self-preservation,| The end, therefore, it may be said, is no longer the mere "self-preservation" found in adaptation to environment, but the "self-development" which implies temporary disharmony between organism and surroundings.
For "self-preservation" and "self-development," though frequently spoken of as identical, are really distinct and often opposed notions—the former denoting a tendency to persist in one's present state of being, while the latter implies more or less change. It may be held, however, that for an organism such as man to persist in his state of being, implies modification of his faculties, and that this modification involves development. For any organism to exist apart from change is, of course, impossible. Life is only known to us as a series of changes. But that change does not necessarily mean development or "change to a higher condition." Degradation is as well known a fact as development; and between the two, there is room for a state of existence of which it is difficult to say whether it improves or deteriorates. And whatever may be intended by the phrase, "self-preservation" points to a state of this kind rather than to an improving condition. The notion of "self-development" has therefore a richer content than that of "self-preservation"; but just on this account it cannot be explained by a reference to the nature of things as they are.
thus taking account of variability
It is true that self-development can only go on by a continuous process of adjustment; but it is also necessary for it that this tendency to adaptation should be continually hindered from becoming complete or lapsing into equilibrium. It is here that the function of variation comes in. On the one side there is this tendency to vary after a fashion often without any apparent regard to external conditions; on the other side, there is the action of the external conditions selecting and favouring those variations which bring the organism into closer correspondence with them. The wide range over which the theory of natural selection applies is due to the fact that the environment is never uniform and never constant, so that modifications on the part of the organism have a chance of suiting its varied and changing character. Its changes, moreover, are often the result not so much of any absolute alteration in external circumstances, as of a new relation between them and living beings having been brought about. For the enormous reproductive faculty of most organisms makes them multiply so rapidly as to press ever more and more closely against the limit of subsistence, and thus to produce competition for the means of living. Hence the fresh lines of development originated by each organism have to be tested by their correspondence with a constantly changing medium. The altered circumstances give the modifications which organisms are for ever striking out an opportunity of perpetuating themselves.
which complicates the tendency to correspondence with environment,
By each new variation the existing relation between organism and environment is disturbed. The variation may, however, prove its utility at once by a more exact correspondence than before with the requirements of external conditions. But, in what are called the higher grades of life, variations from the type are sometimes not immediately useful, although they may ultimately become most advantageous.[229] Were it not for the remarkable power of persistence possessed by the higher animals, the modified organism would be unable to hold its own. The great majority of such eccentric or extraordinary variations do, as a matter of fact, soon disappear, because unable to prove their utility. But others of them, either by the power they give the organism to mould circumstances to itself, or by their appropriateness to the greater complexity which comes with the increased number of living organisms, and the more delicate readjustment it requires, prove themselves to be fitter to live than if no variation had taken place and the preceding state of relative equilibrium had been maintained. The higher adjustment of life to its surroundings, which marks each stage of advancing evolution, had its beginning in the rupture of the original simpler harmony that previously existed.
especially in human conduct.
If we compare human conduct with that of animals lower in the organic scale, it becomes evident that there is a broad difference between the two in this, that actions in the former are purposed, performed with a definite end in view; whereas, in the latter, they seem to be the blind result of impulse, and there are slight, if any, traces of purpose. In activity of the latter kind, natural selection works in the ordinary way by choosing for survival the animals which behave so as best to suit their environment. But actions done with a view to an end may anticipate the verdict of this natural law. The agent may see that conduct of a particular kind would conduce to the promotion of life, while conduct of a different kind would render him less fit to live; and, as a consequence, the former action may be chosen. In this way development may be anticipated, and the present order of affairs may be disturbed, more or less forcibly, in order to bring about a foreseen better state of things.