DARWIN'S PLACE IN FUTURE BIOLOGY 45 



Then Mr. Wallace goes on to speak of the letter from Mr. Darwin 

 containing the quotation given above, and says : 



The words I have italicised (the same italicized in my quotation) and the 

 whole tone of his letters, led me to conclude that he had arrived at no definite 

 view as to the origin of species, and I fully anticipated that my theory would 

 be new to him, because it seemed to me to settle a great deal. 9 



There you have the difference between the two men's minds, at least 

 in their attitude toward survival of the fittest, put in a nut-shell by 

 "Wallace himself. What seemed to him from two days' reflection able 

 "to settle a great deal," seemed to Darwin after twenty years' reflec- 

 tion, not able to " fix or settle anything." 



Another highly instructive exemplification of this difference is 

 furnished by a discussion between the two on natural selection and 

 sterility. This is given us in " More Letters of Charles Darwin," let- 

 ters 209-216, the correspondence having been carried on in 1868. 

 Wallace presents (letter 211) "what appears to me a demonstration on 

 your own principles, that natural selection could produce sterility of 

 hybrids." Darwin's general position on the point is well indicated in 

 letter 213. He says: 



I have been considering the terrible problem. Let me first say that no man 

 could have more earnestly wished for the success of Natural Selection in regard 

 to sterility than I did, and when I considered a general statement (as in your 

 last note) I always felt sure it could be worked out, but always failed in detail. 

 The cause being, as I believe, that Natural Selection can not effect what is not 

 good for the individual, including in this term a social community. 



Although Darwin was sure there was something wrong in Wallace's 

 argument, and was not budged an inch by it, he seems not to have rec- 

 ognized its logical preposterousness. He did not explicitly point out 

 to Mr. Wallace that since over-productivity, or geometrical increase, is 

 one of the fundamental presuppositions of natural selection, to sup- 

 pose natural selection could produce sterility would make it capable of 

 negativing one of its own presuppositions. Stating the matter figura- 

 tively, Darwin saw no logical difficulty in the supposition that natural 

 selection might commit suicide. With him it was merely a question 

 of whether it does this or not, and he could not make out from the evi- 

 dence that it does. But he did not see that Wallace's argument carried 

 out consistently would not only enable natural selection to commit 

 suicide, but in reality would make it able to prevent itself from coming 

 into existence. 



The scope and balance of Darwin's mind are seen nowhere to better 

 advantage than in his efforts to prevent his own causal hypothesis from 

 going beyond bounds. Nevertheless the true inwardness of the differ- 

 ence between himself and those who later were to produce the so- 

 called neo-Darwinian school, the school founded on the omnipotence of 



Poulton, " Darwinism," p. 88. 



