708 Studies in the Theory of Descent. 



inconceivable as the idea that lightning is the 

 electric discharge of a thunder-cloud, of which the 

 formation and electrical tension depends upon 

 causal forces, and of which the time and place are 

 purely determined by such forces, but that Jupiter 

 has it nevertheless in his power to direct the 

 lightning flash according to his will on to the 

 head of the guilty. 



Now although I deny the possibility or con- 

 ceivability of the contemporaneous co-operation 

 of teleological and of causal forces in producing 

 any effect, and although I maintain that a purely 

 mechanical conception of the processes of nature 

 is alone justifiable, I nevertheless believe that 

 there is no occasion for this reason to renounce 

 the existence of, or to disown, a directive power ; 

 only we must not imagine this to interfere directly 

 in the mechanism of the universe, but to be rather 

 behind the latter as the final cause of this 

 mechanism. 



Von Baer himself points this out to us, although 

 he does not follow up the complete consequences 

 of his arguments. He especially insists in his 

 book, which abounds in beautiful and grand ideas, 

 that the notions of necessity (causality) and of 

 purpose by no means necessarily exclude one 

 another, but rather that they can be connected 

 together in a certain manner. Thus, the watch- 

 maker attains his end, the watch, by combining 

 the elastic force of a spring with wheel-work, i. e. 



