ORGANIC EVOLUTION — MENTAL 177 



himself to an environment of vastly greater complexity. 

 By means of written symbols, representing words or 

 thoughts, he is not only able to store in a form easily 

 available to himself, his fellows, and his descendants ac- 

 cumulations of knowledge so immense that no memory 

 could contain them, but by means of these symbols he is 

 able (c. fj. in the mathematics) to perform feats of think- 

 ing utterly beyond the powers of the unaided mind ; just 

 as by means of tools, machinery, and other mechanical 

 contrivances he is able to perform physical feats utterly 

 beyond the unaided powers of his body. To written 

 symbols representing w^ords or thoughts is due, prac- 

 tically speaking, his whole advance beyond the savage 

 in the past, and to them are due also his vast potenti- 

 alities for future advance. 



X 



