CHAPTER IV 



Natural Selection since Darwin 



Controversies over natural selection. — A. R. Wallace; exclusive 

 selectionism. — The Neo-Darwinians ; A. Weismann. — The 

 theory of panmixia. — A discussion of selection. — The strug- 

 gle against nature and the struggle against individuals. — Is 

 rigorous selection an element of progress ? — The part played 

 by favourable conditions. — Chance and the individual char- 

 acters. — Isolated characters and groups of characters. 



THE theory of natural selection could not have 

 been discussed intelligently or with good re- 

 sults until the transmutation idea had won a complete 

 and decisive victory. But for the triumph of the 

 central idea which dominated the Darwinian move- 

 ment during its first years of struggle, it would have 

 been impossible in the following years to approach 

 the subsidiary questions raised by Darwin. 



The ground had first to be cleared before the par- 

 tisans of transmutation could, while ignoring the ar- 

 ; guments pursued outside of the scientific field, 

 discuss the various factors which bring about the 

 descent of species. Foremost among those factors 

 was natural selection, for Darwin's book had from 

 the very first overshadowed the works of his fore- 



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