HUMAN IMPLICATIONS 211 



In doing so I must recognize these two funda- 

 mental principles, the struggle for existence and the 

 necessity for co-operation, both of which, consciously 

 or unconsciously, penetrate all nature; and I shall 

 say now that we may find that these two principles 

 are not always in direct opposition to each other; 

 that there is evidence that these basic forces have 

 acted together to shape the course of evolution, even 

 the evolution of social relations among men and na- 

 tions of men. 



If, in the past, we have not had facts on which 

 to base rational conclusions about national problems, 

 it cannot be said that we have not had powerful 

 emotions to drive us into one attitude or the other. 

 It is very difficult to keep an objective, unemotional 

 attitude toward the complex subject of the biology 

 of war. We may not agree in our placing of the 

 emphasis, but I trust that when we disagree it will 

 be on a healthy intellectual level. 



It is clear that we are entering a tricky field where, 

 to a greater extent than usual, the evidence is not 

 all in, and one in which much that we think we 

 know is contradictory. No one can bring this prob- 

 lem into the laboratory for careful testing. We must 

 do the best we can with inforraation which is more 

 incomplete and faulty than that on which we nor- 

 mally base our biological discussions. The human 



