18 FROM THE GREEKS TO DARWIN 



human body to certain functions, of the survival 

 of the fittest organisms, and finally of the sur- 

 vival of the fittest organs. 



As each part of every organism begins as a 

 rudiment and follows its own independent his- 

 tory, so each of these subsidiary ideas of Evolu- 

 tion rose in a crude form and became increas- 

 ingly clear and definite. 



We have, then, three objects in view: first, to 

 follow the rise of the broad idea of Evolution as 

 a natural law ; second, to trace back the birth and 

 development of each of its subsidiary ideas; 

 third, to keep constantly in mind the changing 

 environment of knowledge and prejudice. The 

 uncongenial influences were by no means con- 

 fined to those of ecclesiastic dogma; the intro- 

 duction and long persistence of scientific falla- 

 cies, such as abiogenesis, or spontaneous origin 

 of life, the uncertain methods of scientific think- 

 ing, the limited knowledge of Nature and espe- 

 cially of animal and plant life, are all to be con- 

 sidered. As these were cleared away, the intel- 

 lectual environment of the evolution idea be- 

 came more congenial, and the idea began its un- 

 checked development. 



If we look at the idea in itself, we first dis- 

 tinguish between the law of Evolution as an ex- 

 planation of the origin and ascent of all forms 

 of life ; second, the evidences for such a law, and 



