PROBLEM OF CAVE BLINDNESS 253 



blind variant will go on proving all things, and it 

 will hold fast to its cave if it gets there. In its 

 automatic elimination of the relatively unfit the 

 environment does in a metaphorical sense select 

 organisms, but the correlated fact is that organisms 

 seem often quite literally to select their environ- 

 ment. Just as an animal with well-developed eyes 

 will try to get out of the cave into which it has been 

 washed, so a blind animal arising as a variant in 

 the open may actively grope its way in. 



