84 DARWINISM AND THE PROBLEMS OF LIFE 



This is intelligible enough. Compare this kind of 

 sexual selection with natural selection. In the latter 

 the idea that there must be selection starts from a 

 fact. In the theory, for instance, that the white hares 

 have been developed from darker ones by natural 

 selection, the fact we start from is that white hares 

 show less against the snow than dark ones ; from this 

 we are justified in concluding that the lighter the hares 

 were, the better their chance of escaping the notice of 

 their enemies. But the man who infers from the fact 

 that our actual bullfinches have a red breast, that the 

 female had from the first a preference for red, and was 

 pleased with the increase of colour, is building his theory, 

 not on a well-known fact, but on a hypothesis once more. 

 Our explanation is simple enough, if we say : The bull- 

 finch has a red breast, and consequently the females 

 must have always had a preference for red, while the 

 blue-throated warblers had a preference for blue. But 

 the inference is not scientific, or at least not until we 

 have explained why the bullfinch prefers red and other 

 animals other colours ; and this we cannot do. 



Could we not say that the bullfinch got its red 

 variation by chance, and that it was not exactly the 

 colour, but " the stimulus of novelty," that acted on the 

 females ? But we must not extend this principle, which 

 we only know in the life of human beings, to animals, 

 especially to those only where we find it convenient. 

 The breast of the male bullfinch, which is supposed to 

 have been grey, must have shown tendencies to all 

 kinds of colours, and if the novelty was appreciated by 

 the females, one would have chosen one colour, another 



