By the way, Einstein arrived at this same framework for determining time by pursuing some quite specific, concrete problems in physics. The principle of the theory of relativity—that all time is the time of a certain place—is a principle that is grounded in the very essence of time, insofar as what is present in the sense of being present in nature can be determined only place-wise—i.e., only in terms of a place and relative to a place. There is no absolute perception of time. In a certain sense, as regards something present in nature, I can never simply and directly fix its “now” as given absolutely. Instead, the now is always a “now, when . . .”
Time itself as a whole cannot be perceived, i.e., is not empirically intuitable as something present. Nonetheless time does show up as something given, and in such a way that what gives it remains hidden.
Einstein intuited new principles, then Heidegger rewrote the story of philosophy to make it compatible with the principles of the new physics.