The explanation lies in the fact that the concept of nature doubtless represents its objects in intuition, yet not as things in themselves, but as mere phenomena, whereas the concept of freedom represents in its object what is no doubt a thing in itself, but it does not make it intuitable, and further that neither the one nor the other is capable, therefore, of furnishing a theoretical cognition of its object (or even of the thinking subject) as a thing in itself, or, as this would be, of the supersensible the idea of which has certainly to be introduced as the basis of the possibility of all those objects of experience, although it cannot itself ever be elevated or extended into a cognition.