Theodore Kisiel scrutinizes the horizon.

the lecture courses of 1927 – 30 seek to further elaborate the ecstatical-horizonal unity of temporality, which was begun in § 69c of Being and Time in a section entitled “ The Temporal Problem of the Transcendence of the World. ” Toward the end of this period, the single yet threefold horizon of time is subjected to increasing critique in view of its blatant objectifying tendencies, in particular, the objectification of being itself. As it was hinted above, horizonal temporality will eventually be displaced and replaced by grounding Dasein in the temporal playing field (Zeit-Spiel-Raum), usually simply time-space (Zeit-Raum) (GA65 18/CP 16, GA65 234–235/CP 184–186), which is located in the integral moment (Augenblick) of holistic insight and decision.

The talk that Heidegger first delivered in 1962 entitled “ Time and Being ” most clearly makes the turn into the source and derives meaning and meaningful presence (Anwesen) from out of this meaning-giving source. The source, at first identified neutrally as an It, is initially said to let or allow meaningful presence, Anwesenlassen . The letting is more originally understood as a giving, such that It gives being, It gives time. The giving is then specified further as It sends being, It extends time, or more precisely, time-space. And the It itself? The It that gives is das Ereignis, which “ appropriates being and time into their own out of their relationship ” (GA14 24/TB 19). Moreover, in giving, “ the sending source keeps itself back and, thus, withdraws from unconcealment ” (GA14 27/TB 22). The meaning-giving source itself is self-concealing and remains insuperably concealed, the ultimate facticity beyond which we can go no further.

Pp. 171-2