THE LOGIC OF ORGANIC EVOLUTION. 391 



which involves all negative evidence, might have prevented a 

 generation of logical inconsequence in the discussioo of man's ori- 

 gin. The fact that no so-called connecting links have been found 

 can have no value whatever as evidence until it is shown that the 

 whole earth has been searched and that there are none, and that 

 no such fossils have ever been destroyed by natural processes. 

 The deduction is justified by the evidence from other depart- 

 ments. 



Agassiz, I believe, made the promise to furnish the positive 

 evidence that no such fossils ever existed by showing that the 

 geological series, at least so far as man is concerned, is complete ; 

 and hence that if they ever existed they should have been found. 

 Death interfered with the fulfillment of the promise. He, like 

 others, believed that man appeared at some definite place at some 

 definite time in the world's history. Had he succeeded in proving 

 the geological series complete, he would have caught, not others, 

 but himself, in his logical toils. He first of all men would have 

 been under obligation to show when and where man did appear, 

 and that connecting links were not among the circumstances that 

 immediately preceded his appearance. 



The radical disappearance of objections to the theory before 

 the introduction of new and especially the pertinacity of the old 

 evidence is extremely interesting. There are imperfections in 

 the evidence, many of which can never be removed. But the 

 difficulties are not logical but practical ; they are due to scientific 

 ignorance. In every phase of its development the theory has ful- 

 filled the conditions imposed upon it by logic, and repeated the 

 history of other established scientific doctrines. At first super- 

 ficial and catastrophic, but approaching through formality to 

 Nature's path, biological science finally entered upon an explana- 

 tion of its natural arrangements and formal laws. The theory of 

 evolution itself passed from the condition of a simple induction 

 to the explanation of vast numbers of facts that had been em- 

 pirically discovered ; opened new fields of investigation ; led to 

 the discovery of whole series of phenomena that had been pre- 

 viously overlooked ; and gave rise to confident expectation fre- 

 quently culminating in definite predictions subsequently verified 

 by investigation — until, in the words of perhaps the foremost 

 investigator in America, " we are in fact doing hardly any- 

 thing else to-day than to verify the suggestions which evolution 

 makes." * 



* Whitman. 



