Organic Evolution 15 



whither. These are philosophical questions, and he has to 

 lay them aside during his working hours. 



It is helpful to distinguish, at any rate, the philosophical 

 idea that all things change, from a scientific attempt to record 

 facts and to work out from these facts an understanding of 

 just how it is that changes are brought about. In this second 

 scientific sense, " evolution " is a generalization from a vast 

 multitude of facts, a working hypothesis by means of which 

 the scientist attempts to make an intellectual reconstruction 

 of the world, or to " explain " the relations of various parts 

 to one another. 



"We shall try to keep clear the facts that record the 

 historical process of change in the world and its inhabitants, 

 and to discuss separately the various attempts to explain how 

 it all may have happened, or the theories of evolution. Fi- 

 nally, we shall consider the importance of knowing the facts, 

 and the importance of finding reasonable theories that fit 

 the facts. 



