For ten points, name this founder of German  idealism, who developed the categorical imperative in his Groundwork for the Metaphysics of Morals and claimed that things in themselves could not be perceived in his Critique of Pure Reason.
This man's less famous works include the Prolegomena to Any Future Metaphysics, while his most important work attempts to determine whether a priori synthetic judgments are possible. In that work, this author distinguishes the noumenal and phenomenal realms, and states his intention to create the equivalent of the Copernican revolution in metaphysics. His most famous idea in ethics can be stated either as the  necessity of regarding human beings as ends in themselves. For ten points, name this founder of German  idealism, who developed the categorical imperative in his Groundwork for the Metaphysics of Morals and claimed that things in themselves could not be perceived in his Critique of Pure Reason.
This man's less famous works include the Prolegomena to Any Future Metaphysics, while his most important work attempts to determine whether a priori synthetic judgments are possible.
Immanuel {Kant}