540 MEMOIR OF KIRCHHOFF. 



upon pedagogical but even upon philosopliical grounds) to use hyimtbe 

 ses, even when they are recognized not to be sufficient in all cases, pro- 

 vided they are still the simplest. In line, only that will appear to us 

 simple which is logically true. 



From what precedes one sees how near sometimes mathematical 

 physics approaches to metaphysics. Kirchhoff gave to em])iricism in 

 the theory of cognition, its most precise and most consequent exj)ression, 

 and placed himself accordinglj^ at the acme of the whole of modern 

 mathematical physics. 



Kirchhofl's endeavor after clearness and truth appears also in his 

 philosophical stand-point, and makes him prefer to give the definition of 

 his own problem in the study of nature from a narrow view, rather than 

 to suffer in it even a semblance of a proposition accepted on faith, as 

 nature's conformity to law possibly is. Aud still he analyzed nature 

 not merely as a critical thinker. His greatest discovery shows that he 

 possessed also the alert introspection, the sympathetic investigation, and 

 the intuitive insight into the working of natural forces, without which 

 no true student of nature can make investigations. We repeat, Kirch- 

 hoff' was one of the greatest students of nature, because he was a math 

 ematical physicist in the sense explained above. 



