172 THE THEORY OF EVOLUTION 



of our permanent possessions and that it will in the 

 future continue to direct and condition all lines of 

 intellectual inquiry and advance, I can understand 

 that half a century hence the question may possibly 

 have assumed a very different aspect. Once more 

 quoting from Professor Giesenhagen: "As soon as 

 direct experience brings to light unambiguous nega- 

 tive examples, which can in no way be harmonized 

 with our conclusions from analogy and induction, 

 we must be ready to make a corresponding change 

 in our doctrines and bring them into harmony with 

 the newly recognized truth, for infallibility in mat- 

 ters of science is given to no man. Up till now, 

 however, no such negative examples are known." l 



1 K. Giesenhagen, loc. cit. 



