168 EVOLUTION 



single pg^liaritiJftSr b n t because of their 

 general stability^and efficiency^ As we have 

 already hinted, we must still admit what 

 Darwin admitted more than fifty years ago 

 that it is extraordinarij jf Difficult 

 precisely why one species 



OUS over eynotjipr in thp grpat fettle fnf life. 



Part of the difficulty is to be found in the 

 fact that there is seldom a simple issue. 



As Russell puts it: 



"We should think of each creature as 

 being, as it were, the point of intersection of 

 a number of selection processes, of as many 

 processes as there are significant characters; 

 and since the significance of Characters must 

 change with the, development and ffrowth_of 



jn 



its fHYJ.W n in prL *i so the sum of selection 



is 



must be an ever-changipg 



1 ' Th^ survival or non-survival of the 

 organism will be determined by the^resultant 

 j)f all these selection yfocesses. and though 

 the exact manner of it be extremely complex, 

 it L- will be the most generally efficient organ- 

 ism which will on me average si;yYJve. Its 

 characters will be such as have . remained. 

 * useful' throughout its life, such as have 

 adapted the organism to the generality of 

 life-conditions under which it has lived." 



