to reality and necessity, since the bending back, which is the aspect of withdrawal or refusal of being, occurs in and is necessary for the unfolding of be-ing. Refusal and opening of the cleft of be-ing occur together; they are one occurrence. The abysmal origin of the cleft (“of” in the twofold sense), a cleft which de-cides gods and humans as they are brought into their own, remains in a reserve, withdraws as the cleft opens. It is not an unreachable ground which keeps the “mere possibility” of future histories of be-ing. Instead the bending back of the cleft is understood as ripeness* (Reife); ripeness is not yet a gift* or dissemination* (Verschenkung), but it is in the not yet; it is “pregnant with the originary ‘not’” (C189; B268).
This sense of originating capacity that is a “not” appears earlier in Being and Time in which Heidegger thinks possibility (as capacity) out of the horizonal temporality of being, out of which Dasein temporalizes itself and beings are disclosed. We have seen in the first part of this study how the utmost possibility of being of Dasein is disclosed out of this temporalizing horizon in being-towards-death as the possibility of not-being. It is out of this possibility of not being that Dasein temporalizes itself and that being as such is disclosed. Heidegger also explores this connection between being-towards-death, disclosure, possibility (capacity), and nothingness in section 160 of Contributions, where he says that
being-towards-death, unfolded as essential determination of the truth of Da-sein,9 shelters within itself two fundamental determinations of the cleft* and is their, mostly unrecognized, mirroring in the t/here [Da]: On the one hand what is sheltered here is the essential belongingness of the not to being as such[ . . . ]. On the other hand being-towards-death shelters the unfathomable and essential richness of ‘necessity,’ again as the one cleft of being itself [ . . . ]. (C198f; B282)
The cleft of be-ing opens in the leap as the abysmal occurrence of the truth of be-ing in its most inceptive swaying. This means that the leap is in itself grounding, in the sense that it first opens a historical time-space
9. This means that Da-sein, as Heidegger conceives it in Contributions, does not exhaust itself in being-towards-death but encloses it. See section 163, C200; B285.