Mental Evolution. 487 



ment of a less logical and less coherent system of ideas, 

 both can find admission, if not as congruous, still as 

 neutral. A sense of their incongruity is not aroused. 



But there are some people, it may be said, who con- 

 sciously hold views which they admit to be incongruous ; 

 who base all their scientific reasonings on a continuity of 

 causation, but who, nevertheless, believe in miraculous 

 interruptions of that continuity. In this case, however, 

 the incongruity is made congruous in a higher synthesis. 

 They belie themselves when they suppose that they are 

 holding incongruous views. Stated at length, what they 

 admit is that miraculous interventions are incongruous, 

 not for them, but for those whose whole system of thought 

 is cast in another mould than theirs for the materialist 

 and the infidel. 



I cannot discuss the matter further here. - This is not 

 the place to show, or attempt to show, how the evolution 

 of systems of thought has caused, or is causing, certain 

 ideas, such as that of slavery, religious persecution, the 

 moral and physical degradation of our poor, to reach that 

 degree of incongruity which we signify as abhorrent; or 

 how that evolution has caused yet more primitive ideas to 

 seem positively repulsive. Nor is it the place to show, or 

 attempt to show, how the advance of scientific knowledge 

 has been constantly accompanied by the elimination of 

 incongruous conceptions. I must content myself with the 

 brief indication I have given of the principle of elimination 

 through incongruity as applied to ideas. 



It may be said that such a principle does not account 

 for the origin of the new congruous ideas, but only for the 

 getting rid of old incongruous ideas. Quite true. But I 

 have grievously failed in my exposition of natural selection 

 through elimination if I have not made it evident that this 

 objection (if that can be called an objection which, in 

 truth, is none) lies also at the door of Darwin's gene- 

 ralization.* 



* In both cases, the question to which an answer is suggested is not 

 What variations will arise ? but "What variations will survive ? 



