Critique of Practical Reason
Kant's view of the beautiful and the sublime is frequently read as an attempt to resolve one of the problems left following his depiction of moral law in the "Critique of Practical Reason" — namely that it is impossible to prove that we have free will, and thus impossible to prove that we are bound under moral law. The beautiful and the sublime both seem to refer to some external noumenal order — and thus to the possibility of a noumenal self that possesses free will.