314 II. III
Being and Time

any more than temporality itself has first been put together out of future, past, and present "in the course of time." Temporality "is" not a being [Seiendes] at all. It is not, but rather temporalizes itself. Nevertheless, we still cannot avoid saying that "temporality 'is' the meaning of care," "temporality 'is' determined thus and so." The reason for this can be made intelligible only when we have clarified the idea of being and the "is" as such. Temporality temporalizes, and it temporalizes possible ways of itself. These make possible the multiplicity of the modes of being of Dasein, in particular the fundamental possibility of authentic and inauthentic existence.

Future, having-been, and present show the phenomenal characteristics of "toward itself," "back to," "letting something be encountered." [329] The phenomena of toward ..., to ..., together with ... reveal temporality as the ἐκστατικόν par excellence. Temporality is the primordial, "outside of itself' in and for itself. Thus we call the phenomena of future, having-been, and present the ecstasies of temporality. Temporality is not, prior to this, a being that first emerges from itself; rather, its essence is temporalizing in the unity of the ecstasies. What is characteristic of the "time" accessible to the vulgar understanding consists, among other things, precisely in the fact that it is a pure succession of nows, without beginning and without end, in which the ecstatic character of primordial temporality is leveled down. But this very leveling down, in accordance with its existential meaning, is grounded in the possibility of a definite kind of temporalizing, in conformity with which temporality temporalizes as inauthentic the kind of "time" we have just mentioned. Thus if we demonstrate that the "time" accessible to the common sense of Dasein is not primordial, but arises rather from authentic temporality, then, according to the principle a potiori fit denominatio, we are justified in calling the temporality now set forth primordial time.

In enumerating the ecstasies, we have always mentioned the future first. That should indicate that the future has priority in the ecstatic unity of primordial and authentic temporality, although temporality does not first originate through a cumulative sequence of the ecstasies, but always temporalizes itself in their equiprimordiality. But within this equiprimordiality, the modes of temporalizing are different. And the difference lies in the fact that temporalizing can be primarily determined out of the different ecstasies. Primordial and authentic temporality temporalizes itself out of the authentic future, and indeed in such a way that, futurally having-been, it first arouses the present. The primary phenomenon of primordial and authentic temporality is the future. The priority of the future will itself vary according to the modified temporalizing of inauthentic temporality, but it will still make its appearance in derivative "time."

Martin Heidegger (GA 2) Being & Time (S&S)