BOOKS.
CHARLES DARWIN..
[SECOND NOTICE.]
Ix answering one of Mr. Galton's anthropological circulars in 1874, Darwin wrote,—" My innate taste for natural history was strongly confirmed and directed by the voyage in the 'Beagle." And, in fact, it was during that voyage, for ever famous in the annals of science, or while engaged in working-up the materials collected in the course of it, that all his great theories suggested themselves in outline to his awakened and stimulated intellect. The greatest of all, as we have already seen, had become definite in his mind before he published his Journal of Researches in 1839. The question of the origin of coral-reefs was the subject of study in 1838. In the same year, Darwin read a paper on the formation of mould, and the share taken in it by earth-worms, before the Geological Society. A year earlier, in 1837, he had thought upon the problem of cross-fertilisation of flowers, his solution of which has brought about almost as fundamental a revolution in botany as the theory of natural selection has in biology, and was busy on the key which was, he hoped, to unlock the mystery of the origin of emotional expression. He thus started with a stock of great ideas that most men acquire only after long and patient study, and his career is a wonderful illustration of the importance of hypotheses in science, when followed out in verification with the "rigour and vigour" so distasteful to Mr. Matthew Arnold in the domain of exegetical theology.
No doubt, as Professor Huxley intimates in his characteristic contribation to the second of these volumes, and as Darwin suggests in the autobiography which gives a special charm to the first of them, it was the uniformitarianiam of Lyell, whose
• Life and Letters of Charles Darwin, including an Autobiographical Chapter. Edited by Ms Pon, Francis Darwin. 3 vol, Loon • Murray. 'M. Principles of Geology had appeared in 1830, that disposed the naturalist of the ' Beagle ' to look to natural and known causes for the explanation of the phenomena of organic life. It is easy for us to do so in these days, but it was not so easy fifty years ago. Lyell himself was not always true to his own doctrine. But Darwin grasped it with a completeness then unexampled, and it was because he did BO that, speculative as his genius was, it almost always kept within the bounds of the verifiable, and brought him to conclusions scientific in character even when not strictly accurate in substance. His true glory lies not so much in the suggestion of natural selection as the key to evolutional transmutation, as in the prophetic sense he must have had from the beginning of the verifiability of the theory, without which sense he could never have worked out the elaborate proof of it presented in the Origin of Species. • It is necessary fully to comprehend this, in order rightly to appreciate Darwin's scientific work. For though the principle of selection is not hard to understand, the theory is one of extreme difficulty, and even its author did not—could not, indeed—foresee the extension that has taken place of its applica- tion. Thirty years ago, although evolution had been before the world since the rise of Greek philosophy, and had been quite recently formulated by such a thinker as Herbert Spencer with singular lucidity, it was regarded rather as a curious quasi. metaphysical speculation than as a verifiable hypothesis. Darwin gave it reality in the physical region, and made evolution the master-theory of the scientific age. This result of his genius is sometimes overlooked, because in natural selection is not to be found the whole explanation of organic forms. It does not explain the origin of life, and probably never will explain it. Nor does it explain the begin- ning of variation ; but it may explain in some measure, though Darwin does not say so, the degree of variation, in that the greater the number of variation-forms, the greater is the amount of material for selection to work upon, and the greater the tendency to survival of some among these forms, and so to the accumulation of the tendency to vary. In the same way heredity, though inexplicable in its origin, may be ex- plicable in respect of its gradations, by the Darwinian theory. No amount of variation combined with heredity could, without selection, account for adaptations or slowly mutable species; forms would multiply indefinitely, capable only of more or less artificial classification. All the supplementary hypotheses of which recent years have witnessed the promulgation, are really subsidiary to selection,—even such a one as that of sexual selection, which is due to Darwin himself. They may, some of them, be useful, as showing that the material of selection is not solely the product of variation ; but selection still remains supreme. "All the ingenuity," says Professor Harley, "and all the learning of hostile critics "—and they have been at work for thirty years- " has not enabled them to adduce a solitary fact of which it can be said, this is irreconcilable with the Darwinian theory." This, of course, does not prove the theory, which is probably not sus- ceptible of absolute proof, because we cannot perfectly imitate or reproduce the operations of Nature, whose process is one of minute variation continued and accumulated through long tracts of time. But it warrants, and, indeed, compels, acceptance of it until it shall be supplanted by one of greater generality, the possibility of which was always present to Darwin's mind. In a sense, the theory is of a higher grade than that of gravitation, —for gravitation is an assumption, while the rapid increase of individuals, and their consequent struggle for existence, which, in feet, constitute the theory of natural selection, are verre causx, though undiscovered causes may exist of greater importance in the production of species. A. word may be said, in passing, on the real meaning of the phrases, "struggle for existence" and "survival of the fittest," so often used in con- nection with the Darwinian theory. Neither is an exact expression. The former is of too dramatic a character, and the latter is not true. The competition of organic forms is mostly passive; those that perish, perish through lack of opportunity rather than through the operation of positively adverse influences. Millions of seeds are produced by certain orchids, of which only a very few, perhaps one or two, germinate and thrive, the remainder die chiefly because they "fall on stony ground." Amid the interactions of energies that make up our world, in the long-run, the better adapted forms get pushed, as it were, into their appropriate places in the polity of Nature. But these places are not unlimited in number ; with the process of time they change in shape, and probably
in number too. On the other hand, the production of variation-forms is endless. Hence innumerable forms must perish ; hence, also, species become extinct, new species come into being, and those higher species, genera, are evolved. The forms, however, that are preserved are by no means necessarily the best of those produced. They would be, if selection had perfectly free play. But this is not the case. Selection is some- times assisted, sometimes hindered, by conditions of environ- ment, by mere numbers of individual forms, by the tendency to vary, it may be in a wrong direction, of adaptations themselves, by correlative modifications,—nay, even by chance. For what may be termed relative chance is not an unscientific conception.
The localisation of a form, for instance, may be regarded as relatively fortuitous when not due either to the environment or to any property of its own.
With these considerations before us, it is not difficult to appreciate the Darwinian teleology, which has replaced that of the special creationists, and has so much wider and grander a scope. We can farther see that survival by selection is not con- fined to the forms of life. The principle is equally active in the inorganic world, and in the field of human thought and action. But in these the selection is of a different kind. In the inorganic world, it cannot be said to be of the more fit, for of inorganic teleology nothing is known or can safely be surmised ; while in the organic world, such perfection of existence as may be attainable through the division of functional labour is the evident tendency. In the world of man, the character of the selection varies with the degree of intelligence and knowledge attained by mankind, or by particular societies of men; but the preservation is still of those variations of thought or habit which beat correspond with the genius of the age or stage, modified by the natural conservatism of the race.
Thus, to sum up, we must not expect anything like a complete proof of the Darwinian theory, but only look for a continually advancing proof, which is exactly what we do meet with in every department of science. We must remember, in dealing with the theory, how endlessly complex is the organic world, how little we know of the causes and modes of variation, and of the in- fluences that modify the action of selection ; nor must we forget how little natural selection is susceptible of direct experimental proof. No act of man, for instance, has yet produced forms of common descent sterile with each other. The fact is often used as an objection to the theory, but the answer is that neither " unconscious " nor " methodical " selection has the same teleology as natural selection.
Darwin's later theories have not commanded the anent accorded to those which marked the outset of his career. The doctrine of paugenesis, or the multiplication of cells by free "gemmules," is based upon the assumption that the cell is a distinct unity, which is probably not the case. His explanation of plant-movements, again, is open to exception, but it contains so much that is true, that though not itself a true theory, it will probably lead to one. He seems, also, not always fully to have comprehended that heredity is not a force or power, but a short way of expressing a series of facts ; and his tendency to regard acquired characters as inheritable is much too pronounced. Characters are only inherited when, by causes as yet very indis- tinctly known, they become in the course of time impressed upon the elements of the embryo, and are converted into a pro- perty or strain of the race. The inheritance is not from the individual, but from a series of individuals forming a longer or shorter tract of the line of descent. Lastly, Darwin's derivation of the moral nature of man from that of brutes shows a very defective knowledge of our moral nature, and is not supported by the facts at his command. We shall return to this subject in a future notice, but may add here that it is difficult to examine, side by side, the skeleton of a man and the skeleton of a chimpanzee or gorilla, without admitting the physical community of their ancestry. But even here intermediate forms are still wanting, to which objection, however, the sudden appearance of highly organised dicotyledonous plants (oaks, maples, he.) in the upper cretaceous period may be pleaded by way of answer. Between the mind of man, however, and that of the brutes, the gulf is much wider than that which separates the physical structures of the highest animal and the lowest man. "Of the multitudes [of animals] so various in their nature, so strange and wild in their shapes," writes Cardinal Newman, "we as little know the [mental] state as we can tell of the inhabitants of the sun and moon." The argument which evolves man from an animal form of existence, rests upon an insufficient basis in respect of his
moral nature, and is, indeed, reduced to one of faint analogy. The moral nature of man is not shown in his acts merely, but in the admiration which noble conduct awakes in him ; and there is no proof whatever that brutes are actually capable of any such emotion or of the motives bound up with all human conduct which really inspires our admiration, while, to us at all events, it seems inconceivable that they should possess a trace of either.
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