214 . LUCK, OR CUNNING? 



objection to the belief in the transmutation of species'. 

 If numerous species, belonging to the same genera or 

 families, have really started into life all at once, the 

 fact would be fatal to the theory of descent with slow 

 modification through natural selection" (p. 302). 



Here "the belief in the transmutation of species," 

 or descent with modification, is treated as synonymous 

 with "the theory of descent with slow modification 

 through natural selection ; " but it has nowhere been 

 explained that there are two widely different " theories 

 of descent with slow modification through natural 

 selection," the one of which may be true enough for 

 all practical purposes, while the other is seen to be 

 absurd as soon as it is examined closely. The theory 

 of descent with modification is not properly convertible 

 .with either of these two views, for descent with modi- 

 fication deals with the question whether species are 

 transmutable or no, and dispute as to the respective 

 merits of the two natural selections deals with the 

 question how it comes to be transmuted ; nevertheless, 

 the words " the theory of descent with slow modifica- 

 tion through the ordinary course of things " (which 

 is what " descent with modification through natural 

 selection " comes to) may be considered as expressing 

 the facts with practical accuracy, if the ordinary course 

 of nature is supposed to be that modification is mainly 

 consequent on the discharge of some correlated func- 

 tion, and that modification, if favourable, will tend to 

 accumulate so long as the given function continues 

 important to the wellbeing of the organism ; the 

 words, however, have no correspondence with reality if 



