7o THE SCIENTIFIC EVIDENCES OF 



VI. 



ARGUMENTS DRAWN FROM CERTAIN GENERAL 

 CONSIDERATIONS. 



There are two or three arguments of a 

 somewhat weighty character, which do not fall 

 under any of the previous headings, but which 

 we must not on this account neglect. 



i. It is justly deemed a substantiation of a 

 scientific theory if it is found to furnish an 

 explanation of other classes of phenomena than 

 those for the explanation of which it was first 

 devised. And this is the case with the theory 

 of natural selection in the region of psychology. 

 The theory was first devised to explain the 



