^^-'^-^^'^V'^^S^^^S^^sS^^^^bS^^^^S^^^^^^^^^ 



^>s^ 



Chapter 2 



The Make-Up and the 

 Workings of the Earth 



THE study of evolution carries within itself the special 

 dif&culties of any historical inquiry. There is the 

 need of finding significant documents or evidences, 

 and of ascertaining their dates or time sequences. Then there 

 is the need of interpreting the evidence into an account that 

 is not onlv consistent within itself but also in harmonv with 

 what we know of the workings of things in general. There 

 are many facts regarding past events which may be authentic 

 enough but which the historian considers irrelevant for his 

 purpose. In the same way the student of evolution, who 

 must of necessity begin all of his studies with facts of vari- 

 ation, has accumulated a tremendous body of such factual 

 material only to find that much of it is irrelevant for his 

 purpose. 



The historian often finds spurious evidence. There are 

 forged documents, there are hoaxes, there are deliberate 

 falsifications. There are records that seem to say one thing 

 but really mean something else. There seems also to have 

 been at work a process that we have come in recent years 

 to call propaganda. Such material is significant for the his- 

 torian, but obviously it needs a great deal of critical checking 

 and testing. In the same way the student of evolution finds 

 facts that seem superficially to carrv^ one set of implications 

 but that on more critical examination may mean something 

 totally different. The general form of the whale, for ex- 

 ample, which is enough like a fish to make the ordinary ob- 

 server class these mammals with fishes, has been interpreted on 

 the one hand as showing special creation for life under special 



