Chap. XII.] Philosophy of the Ihman Mind. \ 0!) 



by adding something new to our former idea of 

 the suhject. Thus, when we say all matter is ex- 

 tended^ we form an analytical proposition ; and 

 when we say all bodies have a certain zceight, that 

 is a synthetical proposition, 



*■* Without experience we cannot form any syn- 

 thetical proposition concerning the objects or mat- 

 ter of our knowledge ; but, as the forms of our 

 knowledge are independent of and prior to our ex- 

 perience, we may, witii respect to the pure notions 

 already mentioned, conceive synthetical proposi- 

 tions, or acquire pure science ; and indeed it is 

 only when w^e have pure perceptions and pure no- 

 tions for our objects, that we can arrive at univer- 

 sal and necessary certainty; as is the case in pure 

 mathematics and philosophy, in which we c<jnsi- 

 der truth, abstracted from matter, with respect 

 only to the forms or lav/s of knowledge and voli-* 

 tion. 



" Beside theoretical reason, ]>rof. KHi;t asciibes 

 to man another faculty, which he calls practical 

 reason, endued with power sufficient to in^pel and 

 direct the will, lie asserts that, if this iaculty 

 were not granted, it would follow that practical 

 laws would not be universal moral ])recepts, but 

 only particular maxims, which individuals might 

 prescribe to themselves as the rule of their conduct. 

 To these universal moral laws, j)ractical reason 

 commands our implicit obedience, without any 

 regard to our inclinations or views of advantage. 

 These are, indeed, sometimes at variance with the 

 dictates of duty, but, in order to diminish their in- 

 fluence as obstacles to virtue, our jn\ictical reason 

 must determine us Mrmlv to believe the existence 



