consists in a reaching out that opens up, in which futural approaching brings about what has been, what has been brings about futural approaching, and the reciprocal relation of both brings about the opening up of openness. Thought in terms of this threefold giving, true time proves to be three-dimensional. Dimension, we repeat, is here thought not only as the area of possible measurement, but rather as reaching throughout, as giving and opening up. Only the latter enables us to represent and delimit an area of measurement.
But from what source is the unity of the three dimensions of true time determined, the unity, that is, of its three interplaying ways of giving, each in virtue of its own presencing? We already heard: In the approaching of what is no longer; present and even in the present itself, there always plays a kind of approach and bringing about, that is, a kind of presencing. We cannot attribute the presencing to be thus thought to one of the three dimensions of time, to the present, which would seem obvious. Rather, the unity of time's three dimensions consists in the interplay of each toward each. This interplay proves to be the true extending, playing in the ve!Y heart of time, the fourth dimension, so to speak—not only so to speak, but in the nature of the matter.
True time is four-dimensional.
But the dimension which we call the fourth in our count is, in the nature of the matter, the first, that is, the giving that determines all. In future, in past, in the present, that giving brings about to each its own presencing, holds them apart thus opened and so holds them toward one another in the nearness by which the three dimensions remain near one another. For this reason we call the first, original, literally incipient extending in which the unity of true time consists "nearing nearness," "nearhood" (Nahheit), an early word still used by Kant. But it brings future, past and present near to one another by distancing them. For it keeps what has been open_ by denying its advent as present. This nearing of nearness keeps open the approach coming from the future by withholding the present in the approach. Nearing nearness has the character of denial and withholding. It