III. 



On the Darwinian Hypothesis of Sexual 

 Selection. 



IT seems as if this much-vexed question were as far as ever from 

 being settled. The following pages contain, briefly stated, 

 various facts and considerations that have induced me, in addition to 

 arguments already published, to discard a former belief in " female 

 preferences" as a factor in the evolution of races. I will enumerate, 

 first of all, some miscellaneous objections, passing on later to review 

 the case of one particular species in order to see how far its habits and 

 bodily characters could bear out this hypothesis. 



I. — Some General Considerations. 



It is difficult, at the outset, to obtain a comprehension of the 

 scope of Sexual, in contradistinction to Natural, selection. To which 

 of the two must we attribute the origin of structures, useful both for 

 combative and life-preserving purposes, or that of many colours 

 artistically beautiful and, at the same time, adaptive ? The practical 

 results of both processes seem often to coincide. 



Indeed, whether we should appeal to natural or to sexual selection 

 frequently depends on whether a species can be credited with the 

 conscious appreciation of beauty that entitles it to rank among the 

 " higher animals." Under this term Darwin, Weismann, and other 

 supporters of this principle, include animals as low down as the 

 Arthropoda, but the boundary between them and " lower animals " 

 destitute of artistic discrimination cannot but be arbitrary, consider- 

 ing how little we know of their intellectual and emotional capacities. 

 Another thing is no less certain, that sexual dimorphism and compli- 

 cated ornamental colours continue uninterrupted into lower orders. 

 Thus a different cause must be invoked to explain identity of effect. 



Another aspect of the " aesthetic " difficulty is this. Certain 

 secondary sexual characters of "higher animals" are displeasing 

 or inelegant to our eyes. In order to show that their ugliness is 

 nevertheless attractive to them, we are asked to call to mind the 

 extraordinary aesthetic notions of many savage tribes of men. 

 Conversely, to prove that beauty in widely-separated groups of 

 animals must be a source of gratification to themselves, we need 



