2 THE ORIGIN AND EVOLUTION OF LIFE 



which group around the idea of vitalism or the existence of 

 specific, distinctive, and adaptive energies in living matter — 

 energies which do not occur in lifeless matter. 



The more modern scientific opinion is that life arose from 

 a recombination of forces pre-existing in the cosmos. To hold 

 to this opinion, that life does not represent the entrance either 

 of a new form of energy or of a new series of laws, but is sim- 

 ply another step in the general evolutionary process, is cer- 

 tainly consistent with the development of mechanics, physics, 

 and chemistry since the time of Newton and of evolutionary 

 thought since Buffon, Lamarck, and Darwin. Descartes (1644) 

 led all the modern natural philosophers in perceiving that the 

 explanation of life should be sought in the physical terms of 

 motion and matter. Kant at first (lysS'-iyys) adopted and 

 later (1790) receded from this opinion. 



These contrasting opinions, which are certainly as old as 

 Greek philosophy and probably much older, are respectively 

 known as the vitalistic and the mechanistic. 



We may express as our own opinion, based upon the appli- 

 cation of uniformitarian evolutionary principles, that when 

 life appeared on the earth some energies pre-existing in the 

 cosmos were brought into relation with the chemical elements 

 already existing. In other words, since every advance thus 

 far in the quest as to the nature of life has been in the direc- 

 tion of a physicochemical rather than of a vitalistic explanation, 

 from the time when Lavoisier (i 743-1 794) put the life of plants 

 on a solar-chemical basis, if we logically follow the same direc- 

 tion we arrive at the belief that the last step into the unknown 

 — one which possibly may never be taken by man — will also be 

 physicochemical in all its measurable and observable proper- 

 ties, and that the origin of life, as well as its development, will 

 ultimately prove to be a true evolution within the pre-existing 



