4 INTRODUCTION 



parent thought to which Darwin gave such pro- 

 digious impetus. To what result we have labored 

 to add to, or to subtract from, his great concep- 

 tion, the future must decide. The effort is our 

 tribute to the power that has moved us. 



The biological realm was indeed the center of 

 the great movement. Of this central movement 

 and of the varied hnes into which it has deployed, 

 we shall learn through the words of those who are 

 entitled to speak. To these, in a moment, I 

 shall give place. But, though the revolution had 

 its origin in the biological field, it was by no 

 means hmited to it. It soon became a radiant 

 influence so penetrating and so stimulating that 

 it has been felt in every field of thought. No 

 realm of the intellectual world has failed to re- 

 spond to the power of Darwin's method, the can- 

 dor of his spirit, and the force of his clear insight 

 and restrained judgment. 



Darwin not only gave form to the whole trend 

 of evolutionary inquiry, but he chastened and re- 

 fined the moral aspects of thought in all hnes of 

 serious intellectual endeavor. It would be too 

 much to say that he was the father of the evolu- 

 tionary conception or the sole parent of the 

 chastened moral attitude of thought now felt to 

 be binding in the scientific world. We would do 

 him a dishonor most obnoxious to his candid and 

 truthful spirit if we were to assign him more than 

 historic truth amply warrants. We must not 

 fail to recognize that before his time the evolu- 



