NATURAL SCIENCE TO GENERAL SCIENCE. 5 



invited to Gratz as professor of mathematics and moral 

 philosophy ; and that at Leyden, in the beginning of the 

 eighteenth, Boerhave occupied at the same time the chairs 

 of botany, chemistry, and clinical medicine, and therefore 

 practically that of pharmacy as well. At present we 

 require at least four professors, or, in an university with 

 its full complement of teachers, seven or eight, to repre- 

 sent all these branches of science. And the same is true 

 of other faculties. 



One of my strongest motives for discussing to-day the 

 connection of the different sciences is that I am myself a 

 student of natural philosophy ; and that it has been made 

 of late a reproach against natural philosophy that it has 

 struck out a path of its own, and has separated itself more 

 and more widely from the other sciences which are united 

 by common philological and historical studies. This op- 

 position has, in fact, been long apparent, and seems to me 

 to have grown up mainly under the influence of the 

 Hegelian philosophy, or, at any rate, to harve been brought 

 out into more distinct relief by that philosophy. Cer- 

 tainly, at the end of the last century, when the Kantian 

 philosophy reigned supreme, such a schism had never 

 been proclaimed ; on the contrary, Kant's philosophy 

 rested on exactly the same ground as the physical 

 sciences, as is evident from his own scientific works, es- 

 pecially from his ' Cosmogony,' based upon Newton's Law 

 of Gravitation, which afterwards, under the name of 

 Laplace's Nebular Hypothesis, came to be universally 

 recognised. The sole object of Kant's ' Critical Phi- 

 losophy ' was to test the sources and the authority of our 

 knowledge, and to fix a definite scope and standard for 

 the researches of philosophy, as compared with other 

 sciences. According to his teaching, a principle disco- 

 vered a priori by pure thought was a rule applicable to 

 the method of pure thought, and nothing further ; it 



