This essay places Foucault's work into a philosophical context, recognizing that Foucault is difficult to place and demonstrates that Foucault remains in the Kantian tradition of philosophy, even if he sits at the margins of that tradition. For Kant, the forms of intuition—space and time—are the a priori conditions of the possibility of human experience and knowledge. For Foucault, the a priori conditions are political space and historical time. Foucault sees political space as central to understanding both the subject and objects of medicine, psychiatry, and the social sciences. Through this analysis one can see that medicine's metaphysics is a metaphysics of efficient causation, where medicine's objects are subjected to mechanisms of efficient control.