Heidegger's Appropriation of Kant

Being and Time, Heidegger praises Kant as “the first and only person who has gone any stretch of the way towards investigating the dimension of temporality or has even let himself be drawn hither by the coercion of the phenomena themselves” (SZ: 23). Kant was, before Husserl (and perhaps, in Heidegger's mind, more than him), a true phenomenologist in the sense that the need to curtail the pretension of dogmatic metaphysics to overstep the boundaries of sensible experience led him to focus on phenomena and the conditions of their disclosure: thus, the “question of the inner possibility of such knowledge of the super-sensible , however, is presented as thrown back upon the more general question of the inner possibility of a general making-manifest(Offenbarmachen) of beings (Seiende) as such” (GA 3: 10, emphasis supplied). So Kant shouldn’t be read as an epistemologist (contrary to Descartes, for example), but as an ontologist: “Kant's inquiry is concerned with what determines nature as such -occurrent beings as such -and with how this ontological determinability is possible” (GA 25: 75). Heidegger sees this investigation into the “ontological determinability” of entities as an a priori form of inquiry: “what is already opened up and projected in advance ie the horizon of ontological determinability . . . is what in a certain sense is “earlier” than a being and is called a priori” (GA 25: 37). This a priori character of ontological determinability forms the main link between Kant's critical project and fundamental ontology, itself characterised as a form of transcendental philosophy: “transcendental knowledge is a knowledge which investigates the possibility of an understanding of being, a pre-ontological understanding of being. And such an investigation is the task of ontology. Transcendental knowledge is ontological knowledge, i.e. a priori knowledge of the ontological constitution of beings” (GA 25: 186). Thus Heidegger presents his own inquiry into the nature of Being as a way to address the same issue as Kant: “what is asked about is Being -that which determines entities as entities, that on the basis of which entities are already understood, however we may discuss them in detail. The Being of entities ‘is’ not itself an entity” (SZ: 6, emphasis supplied). So Heidegger agrees with Kant on the object of the investigation (the determination of entities), and on the idea that the structure of ontological determination is not itself ontical. What remains unclear, however, is the extent to which