our clues from Kant. We will have to come back to these determinations so as to use them to show why the problematic of the ur-temporal remained hidden from Kant.69
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§24. The function of time in the Transcendental Logic. A characterization of the problematic
First we tried to orient ourselves concretely regarding the general way Kant comes at time, and in so doing we have intentionally left unexplained Kant’s specific formulation of the problem that drives these considerations. Our interpretation took us back to the context that Kant for his part never researched or even envisioned. Kant’s basic aim (to which these considerations in the Transcendental Analytic belong and which they help to realize) is different from a thematic analysis of knowledge or consciousness as such. Our task now is to understand that basic aim more precisely, so as to fundamentally clarify (1) the problem-context within which the phenomenon of time, as we have characterized it, operates, and (2) the way of treating the phenomenon of time which the basic problem-context prescribes. If it turns out to be no accident that time shows up in all the decisive parts of the Critique of Pure Reason, then in the final analysis we will have to formulate the problematic of the Critique  in such way that the question of time stands at the center of that problematic.
I now want to spell out this central problematic, which is not explicit in Kant, and clarify it, starting with what we have already explained. From our encounters so far with Kant’s determinations of space and time, what guidelines for our research have emerged? Within empirical intuition Kant finds pure intuition. In the empirical intuition of the outer world he finds space; in the empirical intuition of one’s own self he finds time; and indeed, space and time are the conditions of the possibility of the givenness of the manifold of their respective areas. But what form of research led Kant to find anything like conditions of the possibility of givenness? He investigates empirical intuition and looks for conditions of possibility in that intuition. That is, he looks for what it is in empirical intuition—or more exactly: in what is intuited in empirical intuition—that is already prior to empirical intuition. And why precisely in empirical intuition? Because empirical intuition is the primary form in which knowledge is carried
69.[Here (Moser, p. 619) Heidegger ends his lecture of Thursday, 4 February 1926, to be followed by that of Friday, 5 February, which opened with a 750-word summary that is omitted in GA 21.]