350 EVOLUTION, OLD AND NEW. 



fore why "the survival of the fittest" should claim 

 to be an especial " means of modification " rather than 

 any other necessary adjunct of animal or vegetable 

 life. 



i find that the late Mr. G. H. Lewes has insisted 

 on this objection in his * Physical Basis of Mind.' I 

 observe, also, that in the very passage in which he does 

 so, Mr. Lewes appears to have been misled by Mr. 

 Darwin's use of that dangerous word " means," and, at 

 the same time, by his frequent treatment of natural 

 selection as though it were an active cause; so that 

 Mr. Lewes supposes Mr. Darwin to have fallen into the 

 very error of which, as I have above shown, he is 

 evidently struggling to keep clear namely, that of 

 maintaining natural selection to be a "cause" of 

 variation. Mr. Lewes then continues : 



" He [Mr. Darwin] separates Natural Selection from 

 all the primary causes of variation either internal or 

 external either as results of the laws of growth, of 

 the correlations of variation, of use and disuse, &c., and 

 limits it to the slow accumulation of such variations 

 as are profitable in the struggle with competitors. 

 And for his purpose this separation is necessary. But 

 biological philosophy must, I think, regard the distinc- 

 tion as artificial, referring only to one of the great factors 

 in the production of species." * 



The fact that one in a brood or litter is born fitter 



for the conditions of its existence than its brothers and 



sisters, and, again, the causes that have led to this one's 



having been born fitter which last is what the older 



* 'Physical Basis of the Mind/ p. 107, 1878. 



