THE PROBLEM OF UTILITY. 487 



species and species. This theory, which, although to some extent 

 held by Darwin himself, I consider to be wholly erroneous, we 

 will now proceed to discuss. 



It may be well first to dispose of a point, made much of by 

 Mr. Komanes, that I do not urge utility as a characteristic either 

 of varieties or of genera and higher groups, and that it is there- 

 fore illogical to claim it for species. But this is a misapprehension, 

 since I do claim that when varieties are constant, are hereditary, 

 and occupy a definite area, and are therefore what Darwin termed 

 "incipient species," the characteristics which distinguish them 

 from the parent species are, to some extent, adaptive and useful, 

 and will become fully so when the variety becomes a fully differ- 

 entiated species. And as to genera and families, it is obvious 

 that every one of their distinguishing characters was once a 

 specific character, since genera are merely groups of species, all 

 of which were derived from one parent species, and which have 

 become more or less isolated by the extinction of intermediate 

 forms. Families are, in the same way, derived from a single 

 genus and ultimately from a single species, and the same reasoning 

 applies to them. The reason why my argument on this question 

 has been limited to species is, because the whole problem is in- 

 cluded in that of species : it is in them that the process and 

 laws of development can be best studied free from many of those 

 complexities of modification and survival of disused and partially 

 aborted parts and organs which often constitute generic or family 

 characters. If every one of the new characters or new com- 

 binations of characters which arise when a new species becomes 

 differentiated from its parent-form, — if every one of these is 

 adaptive and utilitarian, then no higher groups can possess 

 characters other than those which were once adaptive, since 

 genera and families can never acquire new characters except 

 through every one of their component species acquiring those 

 characters. The problem as exhibited in species includes there- 

 fore the problem in all higher groups. 



I have already set forth in some detail the argument for utility 

 founded on the fact of the continuous progress of the discovery 

 of utilities with the continuous growth of our knowledge of the 

 life-histories and inter-relations of plants and animals *. I will 

 therefore now devote more special attention to the fundamental 

 argument, that whereas every modificatioa of a species which 

 * ' Darwinism,' pp. 131-142. 



