 For Heidegger, to exist is to be historical. This does not mean that one simply finds oneself at a particular moment in history, conceived as a linear series of events. Rather, it means that selfhood has a peculiar temporal structure that is the origin of that “history” which subsequently comes to be narrated in terms of a series of events. Existential temporality is not a sequence of instants but instead a unified structure in which the “future” (that is, the possibility aimed at in my project) recollects the “past” (that is, what no longer needs to be done, the completed) so as to give meaning to the “present” (that is, the things that take on significance in light of what currently needs doing). To act, therefore, is, in Heidegger’s terms, to “historize” (geschehen), to constitute something like a narrative unity, with beginning, middle, and end, that does not so much take place in time as provide the condition for linear time. To exist “between birth and death,” then, is not merely to be present in each of a discrete series of temporal instants but to constitute oneself in the unity of a history, and an authentic existence is one in which the projects that give shape to existence are ones to which I commit myself in light of this history. Though it belongs to, and defines, a “moment,” choice cannot be simply “of the moment”; to be authentic I must understand my choice in light of the potential wholeness of my  existence.