SELECTION 451 



gains. But De Vries does not propose to dispense with 

 the theory of Natural Selection. He attaches less importance 

 to intra-specific selection, but not less to the sifting of species 

 by one another and by the environment. Speaking of the 

 Mutation-Theory, Prof. G. H. Parker writes (1913, p. 263) : 

 " Organic evolution, then, is accomplished by occasional 

 strides rather than by many oft-repeated short steps. This 

 theory is in no sense antagonistic to natural selection. In 

 fact, it works effectively only in conjunction with natural 

 selection, for, after all, what determines whether a race 

 showing a trait produced as a mutation will survive or not 

 is natural selection. ... As De Vries himself rightly 

 maintains, the mutation theory is significant only in con- 

 nection with natural selection." 



5. Scientific Critique of Selection Theory. 



As our whole view of Animate Nature is coloured by our 

 position in regard to the scope and importance of the pro- 

 cesses of selection, we must consider some of the most serious 

 objections to the theory. We select three. One of the criti- 

 cisms is thus clearly stated by Prof. G. H. Parker (1913, 

 p. 256) : " The chief objection that has been raised against 

 natural selection is one which was well known to Darwin 

 himself, but which has been gathering strength for some 

 years past. It is to the effect that the initial phases of 

 a favourable variation, as conceived by Darwin, are too 

 slight to be of use to the organism, and consequently they 

 cannot come under the influence of the selective process. 

 When the slight individual differences that Darwin laid so 

 much stress upon are closely scrutinised, it seems scarcely 

 conceivable that they could be, even in the long run, of life- 

 and-death importance to an organism ; in other words, that 



