Preface 



A knowledge of evolution is necessary to any under- 

 standing of the natural world and, above all, of man and 

 his position in that world. For man, in his mind and moral 

 life, as well as in his body, is a product of the evolutionary 

 process and can be understood only in the light of its 

 principles. 



We learn of one aspect of man when we trace the evolu- 

 tion of his mind. The account of this development pro- 

 ceeds from the vague awareness of unicellular creatures, 

 past the blind alleys of instinct which find their furthest 

 extension in the social insects, to the intricate nervous sys- 

 tem and complex mind of modem man. We know more 

 about ourselves, too, when we learn that physical fitness 

 was not the sole determinant of survival. Cooperativeness, 

 or Darwin's "mutual aid," developed simultaneously with 

 physical fitness and has been an equally important factor in 

 determining which of nature's myriad experiments were 

 successful. Even the simplest creatures benefit from associa- 

 tion with their fellows, and all animals exhibit some form of 

 social organization. Social cooperativeness, with the tech- 

 niques of transmitting experience which it eventually de- 

 veloped, evolves slowly to its expression in man's civiliza- 

 tions and his moral life, and is absolutely essential to 

 high-level consciousness and intellect. 



Man is the first creature equipped to gain sufficient 

 understanding to influence his own evolution. As soon as 

 that fact is realized, a knowledge of the evolutionary 

 forces that have formed him assumes the highest priority. 

 Through a knowledge of evolution man may properly cen- 



