xxxii THE DARWIN CENTENARY. [April 23, 



or of any class of men within a community; — the work is coming 

 to be done under the control of the developmental idea. In seeking 

 for the explanation of social phenomena, influences are much dwelt 

 upon which once would have received little attention. Heredity, 

 environment in the broadest sense, adaptation to new conditions, 

 survival, these conceptions necessarily lie in men's minds, and give 

 a direction to their efforts. 



As I have said, the last half century has witnessed something 

 very like a revolution in the field of the sciences which con- 

 cern themselves with man. It may well be asked, why did not this 

 revolution take place earlier ? Was there nothing in an earlier time 

 to suggest all this? to stimulate men to new and better directed 

 efforts? I answer, there was much. He who is familiar with the 

 history of philosophy knows well that there is scarcely one of the 

 great controlling ideas of modern science, which has not had its 

 forerunner in the thought of centuries gone by. Struck out like a 

 spark from the brain of some bold and independent thinker, it has 

 flashed for a moment upon the night and then has gone out. It has 

 not kindled the lamp, the steady flame, in the light of which the 

 world is now doing its work. Ideas can be born out of due time ; 

 unadapted to their environment, they fail to develop and bear fruit. 

 Even a great thought may appear to us disembodied, a speculative 

 audacity which does not stand unequivocally upon solid ground as 

 a thing undeniable, unavoidable, necessarily to be reckoned with, as 

 much an inhabitant of the real world as are we ourselves. Such 

 thoughts can be ignored ; they are seed cast upon stony ground. 



Darwin's great service to science, as we all know, does not consist 

 in the discovery of evolution, or even in the first suggestion of the 

 doctrine of natural selection. It lies in the fact that he made fruit- 

 ful what had been relatively unfruitful. His patient, cautious, 

 scientific demonstration of the value of his ideas in furnishing con- 

 crete explanations of the phenomena of organic life, coming at a 

 time at which the world was ready to understand what he had to 

 offer it, precipitated the great battle the echoes of which can still be 

 heard. He and his successors have made it impossible for us to 

 revert to the thought of an earlier day. The new doctrine is with 

 us, and stares back at us from the pages of scientific works in every 



