xiv ESSAYS OF A BIOLOGIST 



they leave out whole tracts of reality) : in the fewest 

 possible words, one is scientific, the other unscientific ; 

 one tries to use to its fullest extent the intellect with 

 which we have been evolved, the other does not. 

 The thread running through most of these essays is 

 the attempt to discover and apply in certain fields 

 as much as possible of this scientific conception to 

 several different fields of reality. 



Of these essays, ' Progress ' has already appeared in 

 the Hibbert Journal^ ' Biology and Sociology ' in the 

 Monist^ * lis n'ont que de Time ' and * Philosophic 

 Ants ' in the Comhill Magazine^ * Rationalism and 

 the Idea of God ' in the Rationalist Press Annual^ and 

 ' Religion and Science ' in Science and Civilixation^ 

 this year's representative of the annual ' Unity ' series 

 edited by Mr. F. S. Marvin, published by the Oxford 

 University Press. They have all, however, been con- 

 siderably revised and enlarged before appearing in the 

 present volume. I have to thank the proprietors and 

 publishers for kindly permitting me to reprint these. 



Ox^OKD\April 1923. 



