NOTE E.—P. 99.

SCHOOLS OF EVOLUTIONISTS.

It is well to recognise the fact that evolutionists do not constitute a homogeneous party; amid that, while there is a growing disposition 416to acknowledge the reality of Organic Evolution, there is likewise a growing tendency to question the sufficiency of the causes by which Mr. Darwin sought to account for it.

1. From the first there has been an important section of evolutionists, represented by such names as Owen, Mivart, Asa Gray, G. H. Lewes, Dana, and J. J. Murphy (in his Habit and Intelligence), who, with differences among themselves, held that the rise of species could not be accounted for by the Darwinian hypothesis of Natural Selection acting on fortuitous variations. The tendency in this school was to seek the causes of evolution within, rather than without, the organism. Most of them were theistic evolutionists—i.e. they held that the development of organisms could not be explained without the assumptions of intelligence and purpose. Not all who opposed the Darwinian hypothesis were of this class. Mr. G. H. Lewes, e.g., writes: “At each stage of differentiation there has been a selection, but we cannot by any means say that this selection was determined by the fact of its giving the organism a superiority over rivals inasmuch as during all the early stages, while the organ was still In formation, there could be no advantage occurring from it. . . . The sudden appearance of new organs, not a trace of which is discernible in the embryo or adult form of organisms lower in the scale—for instance, the phosphorescent and electric organs—is like the sudden appearance of new instruments in the social organism, such as the printing press and the railway, wholly inexplicable on the theory of descent, but is explicable on the theory of organic affinity” (!).—Physical Basis of Mind, pp. 110, 117.

2. Important differences exist between Mr. Darwin and his fellow-worker in the same field, Mr. A. Wallace, involving a distinction of principle on two vital points. (l) Mr. Darwin’s own views underwent considerable modifications in the direction of recognising that Natural Selection is not an all-sufficient explanation, and that more must be allowed to forces interior to the organism. See his Descent of Man, p.61; and Cf. Mivart’s Lessons from Nature, viii., ix., and the articles of Spencer and Romanes cited below. He specially supplemented it by the hypothesis of Sexual Selection. These alterations on the theory Mr. Wallace rejects, repudiating Sexual Selection, and maintaining the hypothesis in the form in which Mr. Darwin abandoned it. (2) Mr. Darwin held his theory to be all inclusive, embracing man as well as the lower animals; Mr. Wallace holds that there are provable breaks in the chain of evolution, and that man, in particular, has a distinct origin. See Lecture IV.

3. Yet more significant is the recent tendency to revolt against. the authority of Mr. Darwin, and to recognise the existence of large classes of phenomena which Natural Selection does not explain. This change of front in recent discussions on Darwinism is too marked to escape notice. I take one or two examples which may show the drift of opinion.

Mr. G. J. Romanes, who as late as 1882 wrote a book on The Scientific Evidences of Evolution, in which Mr. Darwin’s theory received uncompromising support, afterwards wrote in 1887: “The 417hypothesis of Physiological Selection (his own view) sets out with an attempted proof of the inadequacy of the theory of Natural Selection, considered as a theory of the origin of species. This proof is drawn from three distinct heads of evidence—(l) the inutility to species of a large number of their specific characters; (2) the general fact of sterility between allied species, which admittedly cannot be explained by Natural Selection, and therefore has hitherto never been explained; (3) the swamping influence, upon even useful variations, of free intercrossing with the parent form.”—“Physiological Selection,” in Nineteenth Century, January 1887. The effect of Mr. Romanes’s heresy was to arouse “a storm of criticism” from the orthodox Darwinian party.

Mr. Herbert Spencer has published two papers on “Factors of Organic Evolution,” in which, while still according an important place to Natural Selection, he very greatly restricts its field of action. The articles, he says, “will perhaps help to show that it is as yet far too soon to close the inquiry concerning the causes of Organic Evolution.”—P. 75. In a subsequent article in the Nineteenth Century; he thus delivers his soul: “The new biological orthodoxy behaves just as the old biological orthodoxy did. In the days before Darwin, those who occupied themselves with the phenomena of life passed by with unobservant eye the multitudinous facts which point to an evolutionary origin for plants and animals; and they turned deaf ears to those who insisted upon the significance of these facts. Now that they have come to believe in this evolutionary origin, and have at the same time accepted the hypothesis that Natural Selection has been the sole cause of the evolution, they are similarly unobservant of the multitudinous facts which cannot rationally be ascribed to that cause, and turn deaf ears to those who would draw their attention to them. The attitude is the same; it is only the creed that has changed.”—Nineteenth Century, February 1888.

In a well-written and appreciative Essay on Charles Darwin in “The Round Table Series,” the same criticism is passed upon the theory that from the standpoint of biology too much stress has been laid on Natural Selection. “Natural Selection obviously can never be the cause of modifications in any given individual. . . . Natural Selection cannot cause an iota of modification in structure. . . . In the case of Human Selection, not the least modification in an organism can he produced by the process of selection itself. The modifications somehow produced in the animals selected are transmitted to the offspring; but the cause of modification lies elsewhere than in selection; and it is largely due to man’s own modification of the environment. . . . It would undoubtedly have been better had Darwin omitted Natural Selection as a modifying agent altogether.”—Pp. 22–26.

Even Professor Huxley sounds a wavering note: “How far Natural Selection suffices for the production of species remains to he seen. . . . On the evidence of palaentology, the evolution of many existing forms of animal life from their predecessors is no longer an 418hypothesis, but an historical fact; it is only the nature of the physiological factors to which that evolution is due which is still open to discussion.”—Art. “Evolution” in Ency. Brit.

4. Yet more deep-reaching is the controversy between the older Darwinian and Spencerian schools on the One hand, and the newer school headed by Prof. Weismann on the other, on the subject of the transmissibility of acquired characters. According to Mr. Spencer, “either there has been inheritance of acquired characters, or there has been no evolution.”—Cont. Rev., March 1893, p. 446. But this Weismann, Lankester, and others absolutely deny. See controversy between Mr. Spencer and Prof. Weismann in Cont. Rev, for 1893; and cf. Weismann’s Papers on Heredity (trans. 1889), Einer’s Organic Evolution, Thomson’s Study of Animal Life, chap. xx., etc.

Good general criticisms of the Darwinian theory may be seen in Mivart’s Genesis of Species, Murphy’s Habit and Intelligence, Elam’s Winds of Doctrine, Bouverie Pusey’s Permanence and Evolution (1882), Van Dyke’s Theism and Evolution, Professor Sehurman’s Ethical Import of Darwinism, Principal Dawson’s Modern Ideas of Evolution, Martineau’s Study of Religion, Iverach’s Christianity and Evolution, etc.