22 BRAINS OF RATS AND MEN 



in co-operative effort, sympathy, altruism, and mo- 

 rality. 



Every step in the process of fabrication of human 

 culture has followed the preceding step in causal 

 sequence; at no point have we left the wide realm of 

 natural law; it is deterministic throughout. And we 

 have found a place in our natural system for reflex, 

 instinct, inteUigence, will, emotion, sentiment, ideal- 

 ism, faith, hope, and charity — all in the frame of nat- 

 ural law. Some of these functions are characterized 

 by awareness introspectively experienced while they 

 are going on, without loss of their natural character. 



These are functions of protoplasm which have 

 arisen and survived because, like other stable patterns 

 of living, they are good for us who live on the plane 

 of human social organization. In biological terms, 

 they are adaptive; they have survival value on this 

 plane of living just as truly as greed, ferocity, and 

 cunning have survival value on the ape-and-tiger 

 plane. 



The hereditary ape-and-tiger impulses are strong, 

 and it is easy for us to revert to that plane. But the 

 development of humanity during the eight or ten 

 thousand years of which we have record has been 

 along the lines of progressively more of the mental 

 type of efficiency, and in the most recent phase of 

 this history the alternative is put squarely before us 

 — learn to co-operate with your neighbors (not fight 

 them) or perish from off the earth. 



