lematic objects only. The Ideas must not be taken as assertions 

 or even as hypotheses of real objective things. But, from the 

 standpoint of morals, i.e. of practical reason, what was heretofore 

 a problem now becomes an assertion. The Ideas, formerly only 

 regulative, now become constitutive. "Every employment of 

 reason in respect of an object requires pure concepts of the under- 

 standing (categories), without which no object can be conceived. 

 These can be applied to the theoretical employment of reason, 

 i.e. to that kind of knowledge, only in case an intuition (which is 

 always sensible) is taken as a basis, and therefore merely in order 

 to conceive by means of them an object of possible experience. 

 Now here what have to be thought by means of the categories, in 

 order to be known, are Ideas of Reason, which cannot be given in 

 any experience. Only we are not here concerned with the theo- 

 retical knowledge of the objects of these Ideas, but only with this, 

 whether they have objects at all. This reality is supplied by pure 

 practical reason, and theoretical reason has nothing further to 

 do in this but to think those objects by means of the categories. . . . 

 Now when the categories are to be applied to these Ideas, it is not 

 possible to give them any object in intuition; but that such an 

 object actually exists, and consequently that the category as a 

 mere form of thought is here not empty but has significance, this 

 is sufficiently assured them by an object which practical reason 

 presents beyond doubt in the concept of the summum bonum, 

 namely, the reality of the conceptions which are required for the 

 possibility of the summum bonum, without, however, effecting 

 by this accession the least extension of our knowledge on theoretical 

 principles." l 



So then theoretical reason is limited in the critiques by practical 

 reason. By the latter we are enabled to have knowledge practical 

 knowledge of the objects corresponding to the Ideas. Man, as 

 a moral being, asserts the reality and objective validity of objects 

 which, for theoretical reason, are problematic only, for, in no 

 other way, can the demands of the practical reason be satisfied. 

 But it must not be supposed that by this means theoretical know- 

 ledge is in any way extended. The practical knowledge which 

 we have of God, for example, is not a knowledge given in sensible 



1 Cr. of Pr. R., Abbott's trans. Pp. 233-4. 



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