INTRODUCTION. 377 



and other disciples of the new doctrine. It is our 

 present business to trace the principles of this 

 series of events in the history of philosophy. 



I do not profess to write a history of Astro- 

 nomy, any further than is necessary in order to 

 exhibit the principles on which the progression of . 

 science proceeds; and, therefore, I neglect subor- 

 dinate persons and occurrences, in order to bring 

 into view the leading features of great changes. 

 Now in the introduction of the Copernican system 

 into general acceptation, two leading views operated 

 upon men's minds ; the consideration of the system 

 as exhibiting the apparent motions of the uni- 

 verse, and the consideration of this system with 

 reference to its causes ; the formal and the phy- 

 sical aspect of the Theory ; the relations of Space 

 and Time, and the relations of Force and Matter. 

 These two divisions of the subject were at first 

 not clearly separated ; the second was long mixed, 

 in a manner very dim and obscure, with the first, 

 without appearing as a distinct subject of atten- 

 tion; but at last it was extricated and treated in 

 a manner suitable to its nature. The views of 

 Copernicus rested mainly on the formal condition 

 of the universe, the relations of space and time ; 

 but Kepler, Galileo, and others, were led, by con- 

 troversies and other causes, to give a gradually 

 increasing attention to the physical relations of 

 the heavenly bodies ; an impulse was given to the 

 study of Mechanics (the Doctrine of Motion,) which 



