This chapter reconsiders the role subjectivity would play in the ontology of temporal differentiation. It does so by discussing how Heidegger’s “Da-sein” suggested a non-subjectivist notion of subjectivity. The elimination of subjective foundationalism from the concept of subjectivity does not entail the naturalistic and impersonalist dissolution of the subject. The theoretical tension was already visible in competing interpretations of Dasein’s role in Being and Time. According to Michel Henry, Dasein enables the world by projection [Entwurf], one of its existential constitutions [existenziale Verfassungen], but Dasein is also one being among others within this world—this forced Heidegger into a vicious circle. William Blattner puts emphasis on the first direction and understands Heidegger’s ontology simply as a “temporal idealism”—Dasein, by making possible temporality, becomes the necessary premise of being itself. Blattner thus criticizes Heidegger for not taking seriously the irreducible extendedness which “ordinary time” exhibits. While defending Heidegger, John Haugeland suggests that we distinguish between “Dasein” as an ontological structure and as individual beings, and he recommends that we limit the use of the word to the first sense; by contrast, I discern two distinct yet continuous characterizations of Dasein. Ontologically prior is “disclosedness” [Erschlossenheit] mentioned in Chap. 5 , Division One of Being and Time: Dasein means a “t/here” [da] in contradistinction to its “elsewhere,” which is indispensable for the unfolding (temporal differentiation) of beings. Therefore, it is being [Sein] which, for its own manifestation, must call forth Da-sein. Ontologically derivative and secondary is reflexivity [Jemeinigkeit]: it matters for me to be my individuated self, not because I have some immutable essence, but precisely because I am appropriated and possessed by the unfolding of beings, thus becoming an irreplaceable “t/here” for it. In contrast to subjectivism, which presupposes the faculties of the subject on the basis of reflexive structures such as the cogito, the ontology of temporal differentiation turns reflexivity from an explanans into an explanandum, while the real explanans is the temporal differentiation of being via beings, which is realized through the “t/here” of Dasein alone.