NATURE 



\N(yv. I, 1888 



underlying obscurity of ideas by which I find myself as often 

 completely befogged. 



It appears to me that it is sometimes overlooked that what is 

 usually called the "Darwinian theory" is set out in a book 

 which bears as its title the words, not, as they are usually quoted, 

 "The Origin of Species," but "The Origin of Species by 

 Natural Selection. " These words I regard as a proposition of 

 which the book itself affords what is intended to be the proof. 

 It seemed to me that Mr. Romanes intended to distinctly 

 traverse this proposition, and, this being so, the careful considera- 

 tion of his views became a matter of very great importance. Mr. 

 Romanes now denies that he intended anything of the kind. 

 But the denial comes rather late in the day, because the impres- 

 sion which I received from his paper at the Linnean Society was 

 certainly shared at the time by others. For example, though it 

 is unusual for a purely scientific paper to receive an extended 

 notice in large print in the Times, Mr. Romanes was so 

 favoured, and here is what the Tzwifj (August 16, 1886) says on 

 one of the points on which Mr. Romanes complains that I have 

 misrepresented him : — 



"The position which Mr. Romanes takes up is the result of 

 his perception, shared by many evolutionists, that the theory of 

 natural selection is not really a theory of the origin of species, 

 but rather a theory of the origin and cumulative development of 

 adaptations." Now, I suppose Mr. Romanes would call this an 

 "absurd misrepresentation." If so, it is singular that, as far as 

 I remember, he took no steps to correct the statement of his 

 views to which the Times gave its wide circulation. 



But is it a misrepresentation ? It is not, I think, difficult to 

 cite a good deal of evidence that it is not. Anyone who will 

 take the trouble to refer to the Journal of the Linnean Society, 

 Zoology, vol. xix. p. 345, will find printed in capital letters 

 across a page of Mr. Romanes's paper, "Natural Selection not 

 a Theory of the Origin of Species." Now, everybody knows 

 that the idea of the evolution of organic nature existed in men's 

 minds long before Mr. Darwin. He did not originate ir ; what 

 he did originate was the theory that "natural selection" is 

 the mechanical means by which that evolution has been brought 

 about. Mr. Romanes says roundly that it is not, or words have 

 ceased to have meaning. Well, coming from "the biological 

 investigator upon whom," the Time's tells us, "in England, the 

 mantle of Mr. Darwin has most conspicuously descended," I 

 thought that a "startling paradox," and I said so. There was 

 nothing very novel in this : it only put into other words what 

 Mr. Wallace had already said (Nature, vol. xxxiv. p. 467), 

 when he took exception to Mr. Romanes's " extraordinary state- 

 ment that, during his whole life, Darwin was mistaken in suppos- 

 ing his theory to be 'a theory of the origin of species,' and that 

 all Darwinians who have believed it to be so have blindly fallen 

 into the same error." 



The next point on which Mr. Romanes complains is that 

 I make him say specific difi'erences are not adaptive, while those 

 of genera are. And he calls this an absurd misrepresentation ! 

 It is really too comical, because it is the key of his whole 

 strategic position. When Mr. Romanes read his paper at the 

 Linnean Society, he began by saying that he regarded it as the 

 most important work of his life. And the expression would 

 certainly not have been exaggerated if he had succeeded in 

 establishing what he terms (capitals again) the "inutility," i.e. 

 non-adaptiveness, " of specific characters." Even Mr. Romanes 

 could not assert that all specific characters are non-adaptive. 

 But he asserts (Nature, I.e., p. 314) that "a very large pro- 

 portion, if not the majority, of features which serve to distinguish 

 species from species are features presenting no utilitarian signi- 

 ficance." If this could be proved, it would be quite as eftective 

 as proving the proposition universally in inflicting a deadly blow 

 on the Darwinian theory, the very essence of which is that 

 specific differences must be advantageous. I agree with Mr. 

 Wallace (Nature, I.e., p. 467) " that there is no proof 

 worthy of the name that specific characters are frequently 

 useless." 



I am of course prepared to admit that, in regard to plants, 

 about which only I feel competent to speak, there are a vast 

 number" of specific 'lifferences the adaptive significance of which 

 we are either wholly ignorant of, or, at any rate, very im- 

 perfectly understand. But Mr. Darwin has himself led the way in 

 a host of discoveries which have shown in innumerable directions, ( 

 which had never been previously suspected, the adaptive signi- 

 ficance of plant structures. We seem to me justified, then, in | 

 drawing the conclusion that all specific differences in plants are i 



probably adaptive. This Mr. Romanes calls reasoning in a 

 circle ; to me it seems only a reasonable induction, the validity 

 of which is strengthened every day by fresh observation. 



As to the distinction which Mr. Romanes draws between 

 specific and generic differences, I only summed up what he 

 repeats again and again. Here is a specimen : — " It is compa- 

 ratively seldom that we encounter any difiiculty in perceiving the 

 utilitarian significance of generic and family distinctions, while 

 we still more rarely encounter any such difficulty in the case of 

 ordinal and class distinctions. Why, then, should we encounter 

 this difficulty in the case of specific distinctions ? " In my 

 opinion the actual state of things is exactly the reverse. But, as 

 I discussed this point at some length in my Bath address, I need 

 not touch upon it further. 



I do not undertake to follow Mr. Romanes into all his 

 dialectical subtleties. But the position which I understood 

 him to have taken up in his paper was quite intelligible, and 

 was of very great interest to the biologist. I briefly analyze it 

 as follows : — Mr. Darwin explained the origin of species by 

 natural selection ; this implies that specific differences are 

 adaptive ; but this is not universally the case ; it follows, then, 

 that natural selection is not the explanation of the origin of 

 species except when specific differences are adaptive, which, in 

 point of fact, they are not in the majority of cases. It is clear 

 that this shrivels up the part played by natural selection to very 

 small dimensions, and minimises pretty effectively in proportion 

 the position of the Darwinian theory in the field of biological 

 speculation. The force, however, of the whole train of argument 

 obviously depends, as I have remarked before, on the proof 

 which can be given of the proposition that the majority of specific 

 differences are non-adaptive. When we turn to the part of Mr. 

 Romanes's paper dealing with this vital point, we only find some 

 not very convincing assertions — some of which I think are erroneous 

 — and no facts whatever. This is, however, not very surprising. 

 Mr. Romanes is not a practised naturalist. His method is the 

 very inverse of that of Mr. Darwin. W^e know that the latter 

 for more than twenty \ ears patiently accumulated facts, and then 

 only reluctantly gave his conclusions to the world. Mr. Romanes, 

 on the other hand, frames a theory which looks pretty enough 

 on paper, and then, but not till then, looks about for facts to 

 support it. 



In my view, one is not called upon to give much attention at 

 present to physiological selection. Still, a word or two may be 

 devoted to it. The Times took an exception to the phrase of 

 which I am surprised that Mr. Romanes has taken so far no 

 notice. It says : — " How his theory can properly be termed one 

 of selection he fails to make clear. If correct, it is a law or 

 principle of operation rather than a process of selection." In 

 point of fact, what Mr. Romanes calls physiological selection 

 may be more accurately described as reproductive isolation. He 

 supposes that individuals of a particular species arise which from 

 some cause or other are incapable of breeding with other con- 

 specific individuals. They are therefore in one aspect isolated, 

 as if they were on an oceanic island. This being so, any casual 

 variations which they exhibit will be perpetuated, he thinks, 

 whether adaptive or not. And in this way he also thinks 

 that species distinguished by non-adaptive characters have arisen. 

 The idea is interesting, and Mr. Romanes believes that Mr. 

 Darwin would have welcomed it. We know, however, that it 

 occurred twelve years earlier to Mr. Belt, that Mr. Darwin was 

 acquainted with it, and that "he did not regard it with any great 

 favour." I myself have carefully considered it in connection 

 with a variety of facts, and I have arrived at the conclusion that 

 it is not a principle of very much value. It would take too long 

 to set out the grounds for that conclusion here. But T may point 

 out that such an isolated race would get no immunity from the 

 general struggle for existence, while it would lose all the advantages 

 to be obtained from free intercrossing. I am disposed to agree, 

 then, with Mr. Wallace that, far from such races being "unable 

 to escape the preserving agency of physiological selection," they 

 would be very short-lived. Before leaving the subject, I cannot 

 but remark on Mr. Romanes's singular choice of an alternative 

 name for physiological selection — the "segregation of the fit." 

 Segregation, I agree, is an improvement ; but " fit" lets in the 

 whole train of adaptive ideas, while Mr. Romanes insists that 

 "the variations on the occurrence of which it [physiological 

 selection] depends are variations of an unuseful kind." 



One remark, and I shall conclude all that I propose to say 

 about Mr. Romanes and his theory. What I introduced into 

 my Bath address I had Lad long before in my mind. While I 



