Characters as Adaptive and Specific. 255 



often no more than a matter of individual taste. 

 From the nature of the case there can be no objective, 

 and therefore no common, standards of delimitation. 

 This is true even as regards any one given depart- 

 ment of systematic work ; but when we compare the 

 standards of delimitation which prevail in one depart- 

 ment with those which prevail in another, it becomes 

 evident that there is not so much as any attempt at 

 agreeing upon a common measure of specific dis- 

 tinction. 



But what, it may well be asked, is the use of thus 

 insisting upon well-known facts, which nobody will 

 dispute? Well, in the first place, we have already 

 seen, in the last chapter, that it is incumbent on those 

 who maintain that all species, or even all specific 

 characters, must be due to natural selection, to tell us 

 what they mean by a species, or by characters as 

 specific. If I am told to believe that the definite 

 quality A is a necessary attribute of B, and yet that 

 B is " not a distinct entity," but an undefinable ab- 

 straction, I can only marvel that any one should 

 expect me to be so simple. But, without recurring 

 to this point, the use of insisting on the facts above 

 stated is, in the second place, that otherwise I cannot 

 suppose any general reader could believe them in view 

 of what is to follow. For he cannot but feel that the 

 cost of believing them is to render inexplicable the 

 mental processes of those naturalists who, in the face of 

 such facts, have deduced the following conclusions. 



The school of naturalists against which I am 

 contending maintains, as a generalization deduced 

 from the theory of natural selection, that all species, 

 or even all specific characters, must necessarily owe 



