K ant's biological theories. to I 



necessarily assume two fundamentally different natures : 

 an inorganic nature, wliich must be explained by causes 

 acting mechanically (causae efficientes), and an organic 

 nature, which must be explained by causes acting for a 

 definite purpose (causae finales). (Compare p. 34.) 



This dualism meets us in a striking manner when con- 

 sidering the conceptions of nature formed by Kant, one of 

 the greatest German philosophers, and his ideas of the com- 

 ing into being of organisms. A closer examination of these 

 ideas is forced upon us here, because in Kant we honour one 

 of the few philosophers who combine a solid scientific cul- 

 ture with an extraordinary clearness and profundity of 

 speculation. The Konigsberg philosopher gained the highest 

 celebrity, not only among speculative philosophers as the 

 founder of critical philosophy, but acquired a brilliant name 

 also among naturalists by his mechanical cosmogeny. Even 

 in the year 1755, in his " General History of Nature, and 

 Theory of the Heavens," ^ he made the bold attempt " to 

 discuss the constitution and the mechanical origin of the 

 whole universe, according to Newton's principles," and to 

 explain them mechanically by the natural course of develop- 

 ment, to the exclusion of all miracles. This cosmogeny of 

 Kant, or " cosmological gas theory," which we shall briefly 

 discuss in a future chapter, was at a later day fully estab- 

 lished by the French mathematician Laplace and the Eng- 

 lish astronomer Herschel, and enjoys at the present day 

 almost universal recognition. On account of this import- 

 ant work alone, in which exact knowledge is co^upled 

 with most profound speculation, Kant deserves the honour- 

 able name of a natural philosopher in the best and purest 



sense of the word. 

 6 



