226 ESSAYS OF A BIOLOGIST 



ence and religion which are in conflict, but science 

 and a particular brand of religion. 



The essence of science is free inquiry combined 

 with experimental testing. The result is a body of 

 knowledge, of fact, and explanatory theory, which 

 can properly be regarded as established. By estab- 

 lished, however, we do not mean that it is absolute 

 or immutable — we expect addition and modification. 

 But we also expect that, in the future as in the past, 

 the additions and alterations will not involve the 

 scrapping and rebuilding of the whole edifice, but 

 that it will continue to be harmonious with itself, and 

 to undergo a gradual evolution. This has been so 

 even with such marked changes as the discovery of 

 radioactivity, the new outlook in psychology, or the 

 rediscovery of Mendelism — the new, after apparent 

 contradiction, has been or is being harmoniously in- 

 corporated and organized with the old. 



This in its turn implies that toleration should ever 

 be encouraged by the scientist. Humility cannot be 

 genuine if combined with unsupported dogmatic as- 

 sertion : and the recognition that the ideas of revela- 

 tion and divine personality are such dogmatic asser- 

 tions brings a whole new outlook into being. 



Putting matters in a nutshell, we can say that a 

 system based on revelation or on the pushing of un- 

 supported premisses concerning the nature of God 

 to their complete logical conclusions is bound to re- 

 sult in some degree of hostility to the pursuit of truth 

 for its own sake; whereas a religious system basing 



