144 EVOLUTION 



hereditary variations he gave a causal inter- 

 pretation of the age-long process of Becoming. 

 He made the evolution idea current intellec- 

 tual coin; but his success in making the fact 

 clear and credible was in part due to his 

 discovery of one of the chief factors. 



HUXLEY ON " THE QUINTESSENCE OF 

 DARWINISM." Huxley made this distinction 

 between fact and factors very plain in his 

 essay " On the Reception of the Origin of 

 Species " in Darwin's " Life and Letters." 

 He first states the grounds of his own agnostic 

 position (up to 1858) with respect to the 

 doctrine of evolution as promulgated by 

 Lamarck, Robert Chambers, and even 

 Spencer : " Firstly, that up to that time the 

 evidence in favour of transmutation was 

 wholly insufficient; and, secondly, no sugges- 

 tion respecting the causes of the transmuta- 

 tion assumed, which had been made, was in 

 any way adequate to explain the phenomena." 



He goes on to say : 



" The suggestion that new species may 

 result from the selective action of external 

 conditions upon the variations from their 

 specific type which individuals present and 

 which we call " spontaneous " because we 

 are ignorant of their causation is as wholly 

 unknown to the historian of scientific ideas 



