 Thus, Kant’s criticism of metaphysics simultaneously involves denying the pure use of theoretical reason as an instrument for knowledge of transcendent objects, and defending reason’s ideas as projections or goals that have some significant role to play in the overall project of knowledge acquisition. As we shall see, Kant unfortunately is not as clear as we might like on this issue. Sometimes, he seems to argue that the ideas and principles of reason play a merely heuristic role in guiding and systematizing the knowledge already obtained. Other times, he suggests that these ideas are deeply essential to the project of knowledge acquisition, and that their presupposition is utterly necessary if we are to acquire knowledge. Regardless of how the matter is to be resolved, it is clear that Kant’s criticism of metaphysics does not entail any straightforward rejection of the ideas and principles of reason. Indeed, it appears to be precisely the rational constraint to move to the ideas of reason that binds us to our metaphysical propensities and which thus demands a critique of the kind offered by Kant.