CAUSE OF ITS FAILURE. 87 



dern times, regulate many parts of physics and 

 chemistry. 



If this statement should seem to any one to be 

 technical or arbitrary, we must refer, for the justi- 

 fication of it, to the Philosophy of Science, of which 

 we hope hereafter to treat. But it will appear, even 

 from what has been here said, that there are certain 

 Ideas or Forms of mental apprehension, which may 

 be applied to Facts in such a manner as to bring into 

 view fundamental principles of science ; while the 

 same Facts, however arrayed or reasoned about, so 

 long as these appropriate Ideas are not employed, 

 cannot give rise to any exact or substantial know- 

 ledge. 



We shall, in the next Book, see the influence of 

 the appropriate general Ideas, in the formation of 

 various sciences. It need only be observed, before 

 we proceed, that, in order to do full justice to the 

 physical knowledge of the Greek Schools of philo- 

 sophy, it is not necessary to study their course after 

 the time of their founders. Their fortunes, in respect 

 of such acquisitions as we are now considering, were 

 not progressive. The later chiefs of the Schools fol- 

 lowed the earlier masters; and though they varied 

 much, they added little. The Romans adopted the 

 philosophy of their Greek subjects ; but they were 

 always, and, indeed, acknowledged themselves to be, 

 inferior to their teachers. They were as arbitrary 

 and loose in their ideas as the Greeks, without 



