EVIDENCES OF EVOLUTION. 87 



have descended or have been evolved from simpler ancestors, 

 and these from still simpler, and so on, back to the mist of 

 life's beginnings. None of the evidence is logically demon- 

 strative; we accept the evolution idea because it is a 

 plausible interpretation which is applicable to many orders 

 of facts, and is contradicted by none. 



In accepting the evolutionist interpretation naturalists are 

 unanimous; but in regard to the manner in which the 

 modification of species or the general ascent of life has 

 been brought about, there is much difference of opinion. 

 The fact of evolution is admitted ; debate goes on with 

 regard to the factors (see Chapter XXVIII). 



