72 PHYSICAL BASIS OF CIVILIZATION 



from extermination, this tendency to notice a greater 

 variety of objects, if properly used, has obviously 

 much survival value. This value differs among 

 creatures quantitatively, exactly as their intelli- 

 gence ; thus, if there is less intelligence 1 (less per- 

 ception, less adapted conduct influenced by such 

 perception), then there is less survival value. If 

 greater intelligence, then greater survival value. 

 Therefore, given conditions in which the great ma- 

 jority perish before the reproductive age, and, 

 caeteris paribus, only the most intelligent of both 

 sexes survive. A very small margin of intelligence 

 above that possessed by others is sufficient to make 

 them survive. These most intelligent specimens 

 of one generation, according to the law of progres- 

 sive accumulations explained in the last paragraph 

 of Chapter EI, would then reproduce a new genera- 

 tion, inheriting a still higher order of intelligence, 

 of which, again, the most intelligent only would sur- 

 vive to reproduce another generation, inheriting still 

 another increase of intelligence, and so on for many, 

 many generations. 



As explained in the second chapter, such a pro- 

 cess, in the course of a long series of generations and 

 in the absence of panmixia, is capable of enormously 

 improving and increasing the special traits and ten- 

 dencies possessed by any form of life subject to it. 



1 The word intelligence is used in the text, to designate the 

 faculty by which experiences are acquired, preserved, compared, 

 classified, etc., and combined into conceptions, inferences, con- 

 clusions, etc. 



