The article analyses the Kant's categorical imperative from the point of view of the paradigm of a rational being in: the Foundations of the Metaphysics of Morals. The rational being is free because it exhibits, spontaneity and intelligible causality with respect to the sensible world. The main manifestation of the rational being in the sensible world is self-limitation with respect to the rational beings. God's reason which is practical but "without limitation", plays a paradigmatic role, here, The "article explores the status of freedom as the purpose in itself, as the foundation of sense manifestations, and-as them thing in itself.