70 NO STRUGGLE NO SELECTION 



useful for his purposes, there exists no logical connec- 

 tion whatever ; and, indeed, I shall demonstrate that 

 the principle of selection which man uses to get his 

 modifying results is one which cannot be used by Nature. 



It is another peculiar statement in the passage 

 quoted, that if such modifying and developmental 

 individual variations do occur in the course of many 

 successive generations, we cannot doubt that in each 

 generation advantageous and injurious individual 

 variations determine what individuals shall survive. 

 I cannot discover any connection of any kind between 

 the two assumptions. He would have done better to 

 have assumed favourable and injurious variations doing 

 their work in each generation, and then to have 

 inferred the other. 



I shall allow Darwin to explain in his own words 

 the action of his potent individual variation during 

 the course of many successive generations in which it 

 is active. In the following quotation we have Darwin's 

 conception of the developmental ascent from a variety 

 to a distinct species : " In order that any great 

 amount of modification should be effected in a species, 

 a variety when once formed must again, perhaps after 

 a long interval of time, vary or present individual 

 differences of the same favourable nature as before ; 

 and these must be again preserved and so onward, 

 step by step. Seeing that individual differences of the 

 same kind perpetually recur, this can hardly be con- 

 sidered as an unwarrantable assumption. But whether 

 it is true we can judge only by seeing how far the 



