ix LIMITS OF NATURAL SELECTION IN MAN 187 



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 dis- 

 tinctly in many phenomena, the two most important of which 

 are the origin of sensation or consciousness, and the develop- 

 ment of man from the lower animals. I shall first consider 

 the latter difficulty as more immediately connected with the 

 subjects discussed in this volume. 



WJrnt Natural Sehctim can Not do 



In considering the question of the development of man by 

 known natural laws, we must ever bear in mind the first prin- 

 ciple 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 special- 

 isation or physiological division of labour, can only be brought 

 about in as much as it is for the good of the being so modi- 

 fied. Mr. Darwin himself has taken care to impress upon us 

 that natural selection has no power to produce absolute 

 perfection, but only relative perfection, no power to advance 

 any being much beyond his fellow beings, but only just so 

 much beyond them as to enable it to survive them in the 

 struggle for existence. Still less has it any power to produce 

 modifications which are in any degree injurious to its pos- 

 sessor, and Mr. Darwin frequently uses the strong expression, 

 that a single case of this kind would be fatal to his theory. 

 If, therefore, we find in man any characters, which all the 

 evidence we can obtain goes to show would have been actually 

 injurious to him on their first appearance, they could not 

 possibly have been produced by natural selection. Neither 

 could any specially developed organ have been so produced 

 if it had been merely useless to him, or if its use were not 

 proportionate to its degree of development. Such cases as 

 these would prove that some other law, or some other power, 

 than natural selection had been at work. But if, further, 

 we could see that these very modifications, though hurtful or 



