Heidegger differs from Husserl in that he places the problem of transcendence of Dasein – that incorrigible individuation in being in the universal phenomenon of Lebenswelt – in time and time only, as phenomenology, in its essence, cannot have within its grasp the theological imagination of eternity as supratemporality.
What Schütz understands as “retentional grasp” in temporal correspondence to the phenomenon of horizon – memory as the memorialisation of the past – has an ecstatico-horizonal equivalent in Heidegger’s hermeneutic use of temporality. In retention as memory, Dasein gives itself over to the ecstasis of the past – of being as having-been. Instead of dealing with Husserl’s problem of the “inner duration” of consciousness, in Heidegger’s philosophical treatment there is an ontological continuity of being through its ecstatico-horizonal temporalisation (Zeitigung) in understanding and interpretation, i.e. in the generation of meaning structure in Dasein‘s fundamental comportment to being (Seinsverhältnis) in its being-in-the-world. Being is time, and understanding is temporal; through understanding of being, Dasein is itself temporalised. The metaphysical construct of consciousness in inner duration can be replaced by an existentially projected, finitely temporalised phenomenon of Dasein‘s understanding, with its being-toward-death (Sein zum Tode) as the corresponding ecstatico-horizonal schema. Mortality forms the roots of understanding of being as they extend into Dasein‘s potentiality-of-being (Seinkönnen), which gives it the freedom and the accompanying conscience to exist in this or that way of being, in authenticity or inauthenticity.