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 [pg 146] 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 [pg 147] 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 [pg 148] 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 [pg 149] 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 [pg 150] 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 Chapter III. as a standpoint of general validity in relation to teleology and theology would still hold good. Even an entirely naÏve, anthropomorphic, “supernatural” theology is ready to see, in the natural course of things, in the “causÆ secundariÆ,” the realisation of Divine purpose, teleology, and does not fail to recognise that the Divine purpose may fulfil itself not only in an extraordinary manner, through “miracles” and “unconditioned” events, but also in ordinary ways, “through means” and the universal causal nexus. Thus it is quite consistent even with a theology of this kind to regard the whole system of causes and effects, which, according to the Darwin-Weismann doctrine, have gradually brought forth the whole diversity of the world of life, with man at its head, in a purely causal [pg 151] way without teleological intervention, as an immense system of means marvellous in its intricacy, in the inevitable necessity of its inter-relations, and in the exactness of its work, the ultimate result of which must have come about, but perhaps at the same time was intended to come about. Whether I regard this ultimate result as the mere consequence of blind happenings, or as an intended purpose, does not depend, as we have seen, upon the knowledge gained by natural science, but depends above all on whether this ultimate result seems to me of sufficient value to be thought of as the purpose of a world-governing intelligence, and thus depends upon my personal attitude to human nature, reason, mind, and the spiritual, religious, and moral life. If I venture to attribute worth, and absolute worth, to these things, nothing, not even the fact of the “struggle for existence” in its thousand forms, in its gradually transforming effects, in the almost endless nexus of its causes and results, germinal selection included, can take away my right (and eventually my duty) to regard the ultimate result as an end, and the nexus of causes as a system of means. To enable me to do this, it is only requisite that internal necessity should govern the system, and that the result should not be a chance one, so that it might even have been suppressed, have failed, or have turned out quite differently. Necessity and predetermination are characteristic of the relation between means and purpose. But this requisite is precisely that which natural science [pg 152] does afford us,—namely, the proof that all phenomena are strictly governed by law, and are absolutely predetermined by their antecedents. At this point the religious and the scientific consideration coincide exactly. The hairs of our head, and the hairs in the fur of a polar bear, which is varying towards white, and is therefore selected in the struggle for existence,36 even the fluctuating variations of a determinant in the germ, are “numbered” according to both conceptions. Every variation that cropped up, every factor that “selected” the fit, and eliminated the unfit, was strictly predestined, and must of necessity have appeared as, and when, and where it did appear.37
The whole nexus of conditions and results, the inclined plane of evolution and the power of Being to move up it, has its sufficient reason in the nature and original state of the cosmos, in the constitution of its “matter,” its “energy,” its laws, its sequences and the grouping of its phenomena. Only from beginnings so constituted could our present world have come to be as it is, and [pg 153] that necessarily. Only because the primary possibility and fitness for life—vegetable, animal and human—was in it from the beginning, could all these have come to be. This primary possibility did not “come into being,” it was À priori immanent in it. Whence came this? There is no logical, comprehensible, or any other necessity why there should be a world at all, or why it should be such that life and evolution must become part of it. Where then lies the reason why it is, rather than is not, and why it is as it is?
To this must be added what Weismann himself readily admits and expressly emphasises. The whole theory treats, and must treat plant, animal, and man as only ingenious machines, mere systems of physical processes. This is the ideal aimed at—to interpret all the phenomena of life, growth, and reproduction thus. Even instincts and mental endowments are so interpreted, since there must be corresponding morphological variations of the fine structure of the nervous organ, and instinctive actions are then “explained” as the functions of these. But how “mechanical happening” comes to have this marvellous inwardness, which we call sensation, feeling, perception, thought and will, which is neither mechanical nor derivable from anything mechanical; and, further, how physical and psychical can condition one another without doing violence to the law of the conservation of the sum of energy, is an absolute riddle. But this whole psychical world exists, with graduated stages perhaps as close to each other as [pg 154] in the physical world, but even less capable than these of being explained as having arisen out of their antecedent lower stages. And this psychical world, which is, indeed, related to and dependent upon the corporeal life, as also conversely, has its own quite peculiar laws: thought does not follow natural laws, but those of logic, which is entirely indifferent to exciting stimuli, for instance of the brain, which conform to natural laws. But this world, its riddles and mysteries, its great content and its history, beyond the reach of mechanical theories, is so absolutely the main thing (especially in regard to the question of the possibility of religion), that the question of bodily structure and evolution becomes beside it a mere accessory problem, and even the last is only a relatively unimportant roundabout way of coming at the gist of the business. How completely the evolution of the higher mental faculties transcends such narrow and meagre formulÆ as the struggle for existence and the like, Weismann himself indicates in connection with man's musical sense, and its relation to the “musical” instinct in animals. The same and much more might be alleged in regard to the whole world of mind, of the Æsthetic, ethical and religious, of the kingdom of thought, of science, and of poetry.