View Shopping Cart

CRITICAL REVIEWS

DARWINISM TO-DAY.

BY VERNON L. KELLOGG.

New York: Henry Holt & Co. 1907. With good analytical Table of Contents and an (insufficient) Index.

A BOOK like this has long been greatly needed: and this ever increasing need is admirably met by this volume. Of course, Prof. Kellogg writes from his own point of view, and he would not be human if he did not leave some things to be desired. Readers of his book should supplement it by reading also some such book as Rudolph Otto’s "Naturalism and Religion"; as readers of Otto’s book should certainly supplement it by reading Prof. Kellogg’s. If what Otto has to say, for example, upon teleology, and the relation of teleology to mechanical explanations of phenomena, will help the reader to correct Prof. Kellogg’s unreasonable objection to all that he calls "mystical" in our world-view, Prof. Kellogg will on the other hand give him a far richer knowledge of, if not a deeper insight into, the great debate which has been going on of late upon the factors and processes of the development of organized forms. No one can have been unaware of this debate or of the gradual modifications it has been working in the attitude of the scientific world to the traditional Darwinian conceptions. But the general reader has lacked adequate guidance to an exact estimate of the drift of the discussion, and has been liable to be left in a state of mental confusion or to be unduly swayed by the latest advocate of a special line of theory he may have chanced to read. A comprehensive survey of the whole field of the debate from the hand of a competent guide is what he has needed. And this is what Prof. Kellogg has given us in this volume.

Prof. Kellogg wisely begins at the beginning - with a lucid account of what Evolution means, in general, and what that particular theory of Evolution known as Darwinism really is. And he rightly finds the differentiation of Darwinism, specifically so called, in the Selection Theories - or, let us say, that we may keep our eyes fixed on the real pivot of it all, in the theory of Natural Selection. Keeping this central point well in sight, he next gives his readers a careful and clear account, in no way glozing its extent or its seriousness, of the widespread revolt of biological investigators during the last few decades against the principle of Natural Selection - against ascribing to it the whole work of species-forming, and even at times against ascribing to it any effectiveness or capacity for species-forming. Having thus exhibited the attack on Darwinism in its full reach and force, he next, with equal care and fullness, recounts the defense which has been made of it - a defense sometimes very strong, but always involving certain concessions which go to modify or even to transform the role which is ascribed to Natural Selection in the molding of forms. This leads naturally to a survey of the new theories of species-forming which have been suggested, whether as auxiliary to the theory of Natural Selection, designed to supply its deficiencies, or as alternative to it, designed to supplant it. This survey has not been carried through without betraying Prof. Kellogg’s own predilections; the volume naturally closes, therefore, with a chapter on Darwinism’s Present Standing, in which the results of the debate are summed up and Prof. Kellogg’s own conclusions outlined. These conclusions may be briefly stated in these two sentences (p. 374): "Darwinism, as the all-sufficient or even most important causo-mechanical factor in species-forming and hence as the sufficient explanation of descent, is discredited and cast down." "Darwinism, as the natural selection of the fit, the final arbiter in descent control, stands unscathed, clear and high above the obscuring cloud of battle." That is to say, Prof. Kellogg recognizes in Natural Selection a true cause, actually working in nature, to the control of which the stream of descent is subjected, so that when we look at the whole course of development, we see it moving on under its guidance. But he recognizes also that Natural Selection rather works on the stream of descent than produces it, and accounts rather for the general channel in which it flows, than for itself, whether in its main character or many of its minor characteristics. He evidently conceives himself as standing midway between the contending extremes, allowing to Natural Selection a most important function in species-forming, but denying to it the omnipotence which the Neo-Darwinians are prone to ascribe to it.

The place of Darwin in the history of the evolutionary theories is determined by the fact that he first pointed to a vera causa, actually working in the world, to which could be plausibly ascribed the production of the various forms which occur in the animated universe. The essence of his suggestion consisted in the very simple proposition that if multitudes more beings are born into the world than can possibly live in it, it will be inevitable that those which are least fitted to live in it will be crowded out, which will result naturally in the survival of the fittest in each generation. Thus there will come about the gradual molding of organized beings to fit their environment. The strength of the theory lies in its simplicity, and its apparent appeal to nothing but recognized facts. We all know that overproduction is the law of life. We all know that no two individuals are precisely alike. We are all prepared to allow that in the struggle for existence which seems inevitable in these circumstances it will be the fittest among these unlike individuals which survive. We are equally prepared to admit that, as "like begets like," the fittest will reproduce in their offspring their fitnesses. Who, then, can deny that in the course of innumerable generations going on thus, very considerable modifications from the original stock might be produced? Is there not given here, then, an adequate account of the whole course of development of animate forms?

Certainly the theory looks very simple and convincing. But so soon as we transfer it from the region of imaginary construction to that of fact, difficulties arise. Many of the objections which have been urged against it seem to us, to be sure, to be little justified. These are largely directed against its consistency or completeness as a logical construction. From this point of view, however, as it seems to us, the theory is unassailable. When, for example, it is objected - as it has been persistently objected - that it provides only for the survival of the fittest, not for the production of the fittest; that it leaves unexplained the whole matter of the cause of variation and particularly of the causes of the actual variations which occur; that it has no account to give of the opportune appearance of the variations needed, or of the repeated consecution of variations in the same direction in the line of actual descent - and the like: the mark seems to us to be completely missed. The Darwinian theory does not need to concern itself with the origin of the fittest, the cause of variation, the causes of the specific variations which occur, or their opportuneness or consecution. It is logically complete in the simple postulates of variation, struggle for existence, the survival of the fittest. If we admit, as all must admit, that no two individuals are ever exactly alike, then we must admit that some of these individuals are more fit to exist than others; that is given in the very fact of difference. We need not concern ourselves with how the "fitness" arises; relative fitness is inherent in the mere fact of difference. Neither need we concern ourselves with the objection that relative fitness in some particulars in a given individual may be offset by relative unfitness in other particulars. To estimate in these circumstances which organism is on the whole most fit to survive might puzzle us: it cannot puzzle Nature, which acts simply along the line of the resultant. Wherever two individuals exist it is inevitable that one will be "fitter" than the other: wherever thousands or millions of individuals, generically alike, come into being, there necessarily exist among them some, few or many, who will be "fitter" than the rest. And if these thousands or millions of individuals come into being in such circumstances that the great majority of them must needs be crowded out, the survival of the "fittest" seems certain; and as this process goes on through generation after generation, the line of descent must follow the line of relative fitness.