I.] INTRODUCTORY. 13 



the simple phrase " survival of the fittest." With nothing 

 more than this, can, on the Darwinian theory, all the most 

 intricate facts of distribution and affinity, form, and colour, 

 be accounted for ; as well as the most complex instincts 

 and the most admirable adjustments, such as those of the 

 human eye and ear. It is in great measure then, owing to 

 this supposed simplicity, and to a belief in its being yet 

 easier and more simple than it is, that Darwinism, how- 

 ever imperfectly understood, has become a subject for 

 general conversation and has been able . thus widely to 

 increase a certain knowledge of biological matters : and 

 this excitation of interest in quarters where otherwise it 

 would have been entirely wanting, is an additional motive 

 for gratitude on the part of naturalists to the authors of the 

 new theory. At the same time it must be admitted that 

 a similar " simplicity " the apparently easy explanation 

 of complex phenomena also constitutes the charm of such 

 matters as hydropathy and phrenology, in the eyes of the 

 unlearned or half-educated public. It is indeed the charm 

 of all those seeming " short cuts " to knowledge, by which 

 the labour of mastering scientific details is spared to those 

 who believe that without such labour they can yet attain 

 all the most valuable results of scientific research. It is 

 not, of course, meant to imply that its " simplicity " teJls 

 at all against " Natural Selection," but only that the actual 

 or supposed possession of that quality is a strong reason 

 for the wide and somewhat hasty acceptance of the theory, 

 whether it be true or not. 



In the second place, it was inevitable that a theory ap- 

 pearing to have very grave relations with questions of the 

 ast importance and interest to man, that is, with questions 

 of religious belief, should call up an army of assailants 



