Characters as Adaptive and Specific. i6i 



of adaptations. Consequently, they continue to repre- 

 sent the theory of natural selection as concerned, 

 primarily, with explaining the origin of species, 

 and denounce as a "heretic" any one who regards 

 the theory as primarily a theory of the origin and 

 cumulative development of adaptations— whether 

 structural or instinctive, and whether the adaptations 

 are severally characteristic of species only or of 

 any of the higher taxonomic divisions. Indeed, these 

 naturalists appear to deem it in some way a dis- 

 paragement of the theory to state that it is, primarily, 

 a theory of adaptations, and only becomes second- 

 arily a theory of species in those comparatively 

 insignificant cases where the adaptations happen 

 to be distinctive of the lowest order of taxonomic 

 division — a view of the matter which may fitly 

 be compared to that of an astronomer who should 

 define the nebular hypothesis as a theory of the 

 origin of Saturn's rings It is indeed a theory of the 

 orig n of Saturn's rings ; but only because it is a theory 

 of the origin of the entire solar system, of which 

 Saturn's rings form a part. Similarly, the theory 

 of natural selection is a theory of the entire system 

 of organic nature in respect of adaptations, whether 

 these happen to be distinctive of particular species 

 only, or are common to any number of species. 



Now the outcry which has been raised over this 

 definition of the theory of natural selection is 

 a curious proof of the opposition which may be 

 furnished by habitual modes of thought to an exceed- 

 ingly plain matter of definition. For, I submit, that 

 no one can deny any of the following propositions ; 

 nor can it be denied that from these propositions 



TT M 



