Chap. VII.] THEORY OP NATURAL SELECTION. 275 



principle of classification, this is by no means so para- 

 doxical as it may at first appear. 



Although we have no good evidence of the existence 

 in organic beings of an innate tendency towards pro- 

 gressive development, yet this necessarily follows, as I 

 have attempted to show in the fourth chapter, through 

 the continued action of natural selection. For the best 

 definition which has ever been given of a high standard 

 of organisation, is the degree to which the parts have 

 been specialised or differentiated; and natural selection 

 tends towards this end, inasmuch as the parts are thus 

 enabled to perform their functions more efficiently. 



A distinguished zoologist, Mr. St. George Mivart,has 

 recently collected all the objections which have ever 

 been advanced by myself and others against the theory 

 of natural selection, as propounded by Mr. Wallace and 

 myself, and has illustrated them with admirable art and 

 force. When thus marshalled, they make a formidable 

 array; and as it forms no part of Mr. Mivart's plan to 

 give the various facts and considerations opposed to his 

 conclusions, no slight effort of reason and memory is 

 left to the reader, who may wish to weigh the evidence 

 on both sides. When discussing special cases, Mr. Mi- 

 vart passes over the effects of the increased use and 

 disuse of parts, which I have always maintained to be 

 highly important, and have treated in my 'Variation 

 under Domestication' at greater length than, as I be- 

 lieve, any other writer. He likewise often assumes that 

 I attribute nothing to variation, independently of natu- 

 ral selection, whereas in the work just referred to I have 

 collected a greater number of well-established cases than 

 can be found in any other work known to me. My judg- 



