THE LIMITS OF NATURAL SELECTION, ETC. 333 



excite some surprise among my readers, to find that 

 I do not consider that all nature can be explained on 

 the principles of which I am so ardent an advocate ; 

 and that I am now myself going to state objections, 

 and to place limits, to the power of " natural selection." 

 I believe, however, that there are such limits ; and that 

 just as surely as we can trace the action of natural 

 laws in the development of organic forms, and can 

 clearly conceive that fuller knowledge would enable 

 us to follow step by step the whole process of that 

 development, so surely can we trace the action of 

 some unknown higher law, beyond and independent 

 of all those laws of which we have any knowledge. 

 We can trace this action more or less distinctly in 

 many phenomena, the two most important of which 

 are the origin of sensation or consciousness, and the 

 development of man from the lower animals. I shall 

 first consider the latter difficulty as more immediately 

 connected with the subjects discussed in this volume. 



What Natural Selection can Not do. 



In considering the question of the development of 

 man by known natural laws, we must ever bear in 

 mind the first principle of " natural selection," no less 

 than of the general theory of evolution, that all changes 

 of form or structure, all increase in the size of an 

 organ or in its complexity, all greater specialization or 

 physiological division of labour, can only be brought 

 about, in as much as it is for the good of the being 

 so modified. Mr. Darwin himself has taken care to 



