392 DARWINISM AND THE PROBLEMS OF LIFE 



we owe to natural selection. How could we orientate 

 ourselves in the world if every single object about us 

 were something peculiar and had its special name ? We 

 should have to describe and count so much that we 

 could never make ourselves known to another ; he would, 

 in fact, never have a clear idea of the body we were 

 speaking of, unless we could bring before him a number 

 of bodies which are familiar to him in their common 

 features. There would be no language if there were no 

 general terms. 



We must assume that the nerve-centre that receives 

 a sense-impression was so constituted from the first, even 

 in the animals, as to perceive especially the common 

 features. The fox must have general ideas of " hare " 

 and " man," in order to know which to pursue and which 

 to flee. If all things appeared to him to be unlike each 

 other, everything he met would be something new, and 

 he would not know how to act in relation to it. 



The simpler the life of an animal is, the less advanced 

 are its senses and the more comprehensive its concepts. 

 For the frog there are only " stationary " and " moving " 

 things, and of the latter only "large" and "small." 

 The former it avoids, the latter it pounces on. 



The development of an animal's senses is always in 

 proportion to its habits of life. Hence there are 

 animal senses that can detect the individual better than 

 the corresponding sense in man. Take, for instance, 

 the dog's sense of smell. As a general rule animals 

 recognise individual realities better the more advanced 

 their senses are. Man has created devices for improving 



