286 Studies in the Theory of Descent. 



possible; repetition is here therefore unneces- 

 sary. 



The whole of the present investigation had 

 not been planned when I joined with those who, 

 from the first, admitted the omnipotence of natu- 

 ral selection as an article of faith or scientific 

 axiom. A question which can only be solved by 

 the inductive method cannot possibly be regarded 

 as settled, nor can further evidence be considered 

 unnecessary, because the first proofs favour the 

 principle. The admission of a mysteriously work- 

 ing phyletic power appears very unsatisfactory 

 to those who are striving after knowledge ; the 

 existence of this power, however, is not to be 

 considered as disproved, because hundreds of 

 characters can be referred to the action of natural 

 selection, and many others to that of the direct 

 action of the conditions of life. If the develop- 

 ment of the organic world is to be considered as 

 absolutely dependent on the influence of the en- 

 vironment, not only should we be able here and 

 there to select at pleasure characters which ap- 

 peared the most accessible for elucidating this 

 point, but it becomes in the first place necessary 

 to attempt to completely refer all characters be- 

 longing to any particular group of phenomena, 

 however small this group might be, to known 

 transforming factors. We should then see whether 

 this were possible, or whether there would remain 

 residual phenomena not explicable by known 



