REVIEWS 155 



Bishops could render it opaque. Just such a plausible account was found in 

 Natural Selection. The clergy had previously had no particular difficulty in con- 

 vincing their flocks that evolution, being wicked, could not be true. But when 

 they went on to affirm that, in a struggle for existence, the weak were more likely 

 to survive than the strong, they overtaxed the credulity of the proletariat, and 

 during the latter half of the century were compelled to nourish themselves on 

 leaks, to the great entertainment and satisfaction of their opponents. 



It was not till the proletariat were wholly convinced of Natural Selection, nor 

 till the clergy had at length perceived in it the finger of God, that men of science 

 began to think there was something wrong about it. The Mendelian school 

 arose, protesting that Natural .Selection was greatly overdone ; that at the best it 

 was only a minor factor in organic evolution. And they suggested another factor 

 which, not being an obvious truism, the public were unable to understand. It 

 was pointed out, moreover, that Natural Selection involved an uncritical accept- 

 ance of the telelogical theories current in the early part of the last century — 

 theories, namely, which assumed that every tissue and organ had some special 

 use to the organism or to man — theories which never considered the possibility of 

 useless and irrelevant organs or tissues. Natural selection was based, therefore, 

 on the popular belief in the universal utility of all parts of an organism ; and little 

 effort appears to have been made to investigate what foundations in fact this belief 

 might possess. An illustration from the present work will indicate the difficulties 

 into which evolutionists were thrown by overlooking this fundamental point. 

 Wallace was asked to explain why a wagtail wags its tail. As an extreme Natural 

 Selectionist he was obliged to postulate, not merely some utility for this insigni- 

 ficant action, but some utility of vital importance for the existence of the species. 

 No alternative even entered his mind. Accordingly he explained to his corres- 

 pondent that it was " quite easy " : a hungry hawk pouncing upon a wagtail, 

 wagging its tail, would have its attention so transfixed by the motion of that 

 appendage as to mistake the tail for the entire bird. It would thus miss the bird 

 ■and carry off nothing more substantial than a feather from its tail. Ergo the 

 wagtail escapes, and wagtails in general survive and multiply. Now we should be 

 very glad to know of some positive evidence in favour of a theory which credits a 

 hawk with a degree of stupidity and myopia altogether incompatible with its own 

 survival and multiplication. If I were desirous of shooting a dog, I should not be 

 deluded into aiming at its tail, merely because that appendage was in motion ; yet 

 Wallace's explanation assumes that, if my survival depended on shooting dogs, 

 I should so invariably be misled by their tails, that the canine species would 

 rapidly prosper and multiply owing to my delusion. Far more natural is it to 

 suppose that tail-wagging is a mere outlet of energy released on the sudden 

 cessation of flight, and possessing no evolutionary significance ; in the same way 

 that a grouse or a pheasant is apt to crow on settling, without any suggestion of 

 ventriloquist powers for misleading simple-minded hawks. 



However this may be, it is clear that Natural Selection fitted well into the 

 prepossessions of the times which discovered it. If it should hereafter be estab- 

 lished that Natural Selection is of minor importance as an agency in evolution, 

 then the main value of its discovery will have been its propagandist aspect. On 

 account of its being a truism and being teleological, and being so simple that even 

 a clergyman could understand it, it was capable of hoisting the whole theory of 

 evolution into popular approval. The future historian of science will then, 

 perhaps, regard it as the great scientific hoax of the nineteenth century, and will 

 find some pleasant scope for satire in the circumstance that the public could not 



