Chapter VI. Darwinism In The Strict Sense.
It remains for us to consider what is essentially Darwinian in Darwinism, namely, the theory of natural selection as the determining factor in evolution. For, given the reality of evolution and descent, and that transformations from one form to another, from lower to higher, have really taken place, what was the guiding and impelling factor in evolution, what forced it forwards and upwards? It is here that the real problem of Darwinism begins. Only from this point onwards does the doctrine of evolution, which is not in itself necessarily committed to any theory of the factors, become definitely Darwinian or anti-Darwinian. And it is this problem that is mainly concerned in the discussions taking place to-day as to whether Darwin was right, or whether Darwinism as a hypothesis has not broken down.
The most characteristic feature of Darwin's theory was “natural teleology,” that is, the explanation of what is apparently full of purpose and plan in the world, purely as the necessary consequence of very simple conditions, without purpose or any striving after an aim. He sought to show that evolution and ascent [pg 140] can be realised through purely “natural” causes, that this world of life, man included, must have come about, but not because it was intended so to do. In this sense, indeed, his doctrine is an attempt to do away with teleology. But in another sense it is so even more emphatically. The world, and especially the world of life, is undoubtedly full of what is de facto purposive. The living organism, as a whole and in every one of its parts, is marvellously adapted to the end of performing its functions, maintaining its own life and reproducing. Every single living being is a miracle of inexhaustible adaptations to an end. Whence came these? They, too, are products, unsought for, unintended, and yet necessary, and coming about “of themselves,” that is without teleological or any supernatural guiding principles. To eliminate purpose and the purposive creating and guiding activity of transcendental principles from interpretations of nature, and to introduce purely naturalistic principles—“principles of chance,” if we understand chance in this connection not as opposed to necessity, but to plan and purpose—this is the aim of the Darwinian theory. And it only becomes definitely anti-theological because it is anti-teleological.
The conclusions which Darwin arrived at as to the factors in the transformation of species, and in the production of “adaptations,” have been in part supported by the specialists he influenced, in part strengthened, but in part modified and even reversed, so that a great crisis [pg 141] has come about in regard to Darwinism in the strict sense—a crisis which threatens to be fatal to it. We must here attempt to take a general survey of the state of the question and to define our own position.
Darwin's interpretation is well known. It is the theory of the natural selection of the best adapted through the struggle for existence, which is of itself a natural selection, and results in the sifting out of particular forms and of higher forms. Darwin's thinking follows the course that all anti-teleological thought has followed since the earliest times. In bringing forth the forms of life, nature offers, without choice or aim or intention, a wealth of possibilities. The forms which happen to be best adapted to the surrounding conditions of life maintain themselves, and reproduce; the others perish, and are eliminated (survival of the fittest). Thus arises adaptation at first in the rough, but gradually in more and more minute detail. This adaptation, brought about by chance, gives the impression of intelligent creative purpose.
In Darwin this fundamental mode of naturalistic interpretation took, under the influence of the social-economic theories of Malthus, the special form of natural selection by means of the struggle for existence, in association with the assumption of unlimited and fluctuating variability in the forms of life. All living beings have a tendency to increase in number without limit. But the means of subsistence and other conditions of existence do not increase at the same [pg 142] rate; they are relatively constant. Thus competition must come about. Any organism that is, by fortuitous variation, more favourably equipped than its fellows maintains itself and reproduces itself; the less favoured perish. For all things living are exposed to enemies, to untoward circumstances, and the like. Every individual favoured above its rivals persists, and can transmit to its descendants its own more favourable, more differentiated, more highly equipped character. Thus evolution is begun, and is forced on into the ever more diverse and ever “higher.”
To Darwin this struggle for existence and this selection according to utility seemed, at any rate, the chief factor in progress. He did, indeed, make some concessions to the Lamarckian principle that new characters may be acquired by increased use, and to other “secondary” principles. But these are of small importance as compared with his main factor.