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 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 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 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.

Differences of Opinion As To the Factors In Evolution.

The theory of natural selection in the struggle for existence rapidly gained wide acceptance, but from the first it was called in question from many sides. Bronn, who translated Darwin’s works into German, was and remained loyal to the idea of a “developmental law”—that there is within the organism an innate tendency towards self-differentiation and progress, thus a purely teleological principle.(34) Similarly, von Baer emphasised the idea of an endeavour to realise an aim; von Kölliker, that of “heterogenesis”; Nägeli, that of an impulse towards perfection—all three thus recognising the theory of evolution, but dissenting from the view that the struggle for existence is the impelling factor and actual guide in the process. Very soon, in another direction, antagonism became pronounced between the strictly Darwinian elements of the theory (the struggle for existence and its corollaries) and the accessory Lamarckian elements. Through these and other controversies the present state of the question has emerged.

The main antithesis at present is the following. On the one side, the “all-sufficiency of natural selection” is maintained, that is, progressive evolution is regarded as coming about without direct self-exertion on the part of the organisms themselves, simply through the fact that fortuitous variations are continually presenting themselves, and are being selected and established according to their utility in the struggle for existence. On the other side—with Lamarck—the progress is regarded as due to effort and function on the part of the organism itself. (Increased use of an organ strengthens it; a changed use transforms it; disuse causes it to degenerate. Thus new characters appear, old ones pass away, and in the course of thousands of years the manifold diversity of the forms of life has been brought about.)

Further, by those of the one side variation is regarded as occurring by the smallest steps that could have selective value in the struggle for existence. To the others variation seems to have taken place by leaps and bounds, with relatively sudden transformations of the functional and structural equilibrium on a large scale. In regard to these the _rôle_ of the struggle for existence must be merely subsidiary. This saltatory kind of evolution-process is called “halmatogenesis,” or, more neatly, “kaleidoscopic variation,” because, as the pictures in a kaleidoscope change not gradually but by a sudden leap to an essentially new pattern, so also do the forms of life. Associated with this is the following contrast. One side believes in free and independent variation of any organ, any part, any function, physical or mental, any instinct, and so on, apart from change or persistence in the rest of the organism; the other side believes in the close connectedness of every part with the whole, in the strict “correlation” of all parts, in variation in one part being always simultaneously associated with variation in many other parts, all being comprised in the “whole,” which is above and before all the parts and determines them. And further, to one school variation seems without plan in all directions, simply plus or minus on either side of a mean; to the other, variation seems predetermined and in a definite direction—an “orthogenesis,” in fact, which is inherent in the organism, and which is indifferent to utility or disadvantage, or natural selection, or anything else, but simply follows its prescribed path in obedience to innate law. The representatives of this last position differ again among themselves. Some regard it as true in detail, in regard, for instance, to the markings of a butterfly’s wing, the striping of a caterpillar, the development of spots on a lizard; while others regard it as governing the general process of evolution as a whole. Finally, there is the most important contrast of all. On the one side, subordination, passivity, complete dependence on the selective or directive factors in evolution, which alone have any power; on the other, activity, spontaneous power of adaptation and transformation, the relative freedom of all things living, and—the deepest answer to the question of the controlling force in evolution—_the secret of life_. This last contrast goes deeper even than the one we have already noted, that between the Darwinian and the Lamarckian principle of explanation; and it leads ultimately from the special Darwinian problem to quite a new one, to be solved by itself—the problem of the nature and secret of living matter.

Weismannism.

In regard to almost all the points to which we have referred, the most consistent and decided champion of Darwinism in its essential principles is the zoologist of Freiburg, August Weismann.(35) In long chapters on the protective coloration of animals, on the phenomena of mimicry—that resemblance to foreign objects (leaves, pieces of wood, bark, and well-protected animals) by which the mimics secure their own safety from enemies—on the protective devices in plants, the selective value of “the useful” is demonstrated. In regard to the marvellous phenomena of “carnivorous” plants, the still more marvellous instincts of animals, which cannot be interpreted on Lamarckian lines as “inherited habit,” but only as due to the cumulative influence of selection on inborn tendencies, as well as in regard to “symbiosis,” “the origin of flowers,” and so on, he attempts to show that the heterodox attempts at explanation are insufficient, and that selection alone really explains. At the same time the Darwinian principle is carried still further. It is not only among the individuals, the “persons,” that the selective struggle for existence goes on. Personal selection depends upon a “germinal selection” within the germ-plasm, influencing it, and being influenced by it—for instance, restrained.

In order to explain the mystery of heredity, Weismann long ago elaborated, in his germ-plasm theory, the doctrine that the developing individual is materially preformed, or rather predetermined in the “idants” and “ids” of the germ-cell. Thus every one of its physical characters (and, through these, its psychical characters), down to hairs, skin spots, and birth-marks, is represented in the “id” by “determinants” which control the “determinates” in development. In the course of their growth and development these determinants are subject to diverse influences due to the position they happen to occupy, to their quality, to changes in the nutritive conditions, and so on. Through these influences variations in the determinants may be brought about. And thus there comes about a “struggle” and a process of selection among the determinants, the result of which is expressed in changes in the determinates, in the direction of greater or less development. On this basis Weismann attempts to reach explanations of the phenomena of variation, of many apparently Lamarckian phenomena, and of recognised cases of “orthogenesis,” and seeks to complete and deepen Roux’s theory of the “struggle of parts,” which was just another attempt to carry Darwinism within the organism.

What distinguishes Weismann, and makes him especially useful for our present purpose of coming to an understanding in regard to the theory of selection is, that his views are unified, definite and consistent. In his case we have not to clear up the ground and to follow things out to their conclusions, nor to purge his theories from irrelevant, vitalistic, or pantheistic accessory theories, as we have, for instance, in the case of Haeckel. His book, too, is kept strictly within its own limits, and does not attempt to formulate a theory of the universe in general, or even a new religion on the basis of biological theories. Let us therefore inquire what has to be said in regard to this clearest and best statement of the theory of selection when we consider it from the point of view of the religious conception of the world.

Whatever else may be said as to the all-sufficiency of natural selection there can be no doubt that it presupposes two absolute mysteries which defy naturalistic explanation and every other, and which are so important that in comparison with them the problem of the struggle for efficacy and its meaning fades into insignificance. These are the functions and capacities of living organisms in general, and in particular those of variation and inheritance, of development and self-differentiation. What is, and whence comes this mysterious power of the organism to build itself up from the smallest beginnings, from the germ? And the equally mysterious power of faithfully repeating the type of its ancestors? And, again, of varying and becoming different from its ancestors? Even the “mechanical” theory of selection is forced to presuppose the secret of life. Weismann indeed attempts to solve this riddle through his germ-plasm theory, the predisposition of the future organism in the “ids,” determinants, and biophors, and through the variation of the determinants in germinal selection, amphimixis and so on. But this is after all only shifting the problem to another place, and translating the mystery into algebraical terms, so to speak, into symbols with which one can calculate and work for a little, which formulate a definite series of observations, an orderly sequence of phenomena, which are, however, after all, “unknown quantities” that explain nothing.

In order to explain the developing organism Weismann assumes that each of its organs or parts, or “independent regions,” is represented in the germ-plasm by a determinant, upon the fate of which the development of the future determinate depends. It is thought of as a very minute corpuscle of living matter. Thus there are determinants of hairs and scales, pieces of skin, pits, marks, &c. But every determined organ, or part, or “independent region,” is itself in its turn an “organism,” is indeed a system of an infinite number of interrelated component parts, and each of these again is another, down to the individual cells. And each cell is an “organism” in itself, and so on into infinity. Is all this represented in the determinants? And how?

Further, the individual determinate, for instance of a piece of skin, is not something isolated, but passes over without definite boundary into others. Therefore the determinants also cannot be isolated, but must be systems within systems, dependent upon and merging into one another. How, at the building up of the organism, do the determinants find their direction and their localisation? And, especially, how do they set to work to build up their organ? Here the whole riddle of the theory of epigenesis, which Weismann wished to do away with as a mystery, is repeated a thousand times and made more difficult. In order to explain puzzling processes on a large scale, others have been constructed, which on close investigation prove to be just the same mysterious and unexplained processes, only made infinitely smaller.

Moreover, even if the whole of “Weismannism,” including germinal selection, could be accepted, and if it were as sufficient as it is insufficient, what we advanced at the end of