NATURAL PHILOSOPHERS. 89 



These were original departures, in which these 

 writers were thoroughly logical and sound, and 

 were laying foundations for those observations 

 which finally led to the establishment of the Evo- 

 lution theory. Yet it must not be inferred that 

 the Evolution of life was a very prominent ele- 

 ment in their philosophy. 



In the larger aspect of their teaching, namely, 

 in the broad question of Evolution itself as the 

 law of the Universe, they all found their inspira- 

 tion in Greek literature. Bacon did not put forth 

 a general Evolution system; Descartes and Leib- 

 nitz, who were the first to do so, drew from Greek 

 poetry and philosophy, and the same is true of 

 all the later philosophers. Kant and the later 

 German philosophers drew not only from these 

 sources, but from suggestions found in contempo- 

 rary science, from Linnaeus and especially from 

 Buffon. It is very probable also that careful search 

 among the earlier naturalists would reveal an antici- 

 pation of some of the problems which are set forth 

 in Bacon and Leibnitz. 



Their first great gift, as we have said, was in 

 establishing the right trend to observation ; their 

 second o:ift was the outcome of their battle for the 

 principle of natural causation. From Bacon to 

 Kant, who, it is true, wavered in advocating this 

 principle, this was a theme of the first rank ; that is, 

 the operation of natural causes in the world rather 

 than of the constant interference of a Creator in 



