In Being and time Heidegger provides a phenomenology through which fundamental ontology, as the primordial theory of existence that grasps being as it is without the metaphysical distortions of traditional philosophy, approaches the ecstatico-temporal existence of Dasein with an emphasis more on homo faber rather than homo sapiens. Phenomenology, by its hermeneutic turn in Heidegger, places being-in-the-world (In-der-Welt-sein) before epistemology – or praxis before theoria. This is because Dasein, as existent (existierend), exists through being “thrown” (geworfen) in the world while projecting itself through the three ecstases (Ekstasen) of time (past, present, future).
By its very definition, the “hermeneutic” assumes a horizon of finitude in the phenomenon of understanding, against which interpretation takes place as being (Sein) appropriates the being of Dasein. Dasein is never equal to the full plenitude of being, nor its abyssal nothingness – in fact it exists through a fundamental ontological differentiation between being (Sein) and beings (Seiende). The finite horizon of Dasein in its understanding of being (Seinsverständnis) means that it is oriented towards the world in which it exists, not alone but in the “thrown” phenomenon of Mitdasein – being-with-one-another as the sociality of the human being – in one way or the other, so that it is sensible for us to talk about Dasein‘s existential pathway. Being both hermeneutic and phenomenological, Dasein does not walk its path in the abstract, nor in the abstraction of knowledge, but in a fundamental attunement to the presence (Vorhandenheit) of other beings. Presence as the foremost mode of being (Seinsmodus) in the world, which makes possible the manifold of phenomena – both visible and invisible, tangible and intangible, sustainable and threatening – enables and in fact empowers Dasein to exist among beings in its being-in-the-world and not be shocked into a permanent state of bewilderment. A child grows up and learns precisely because this mode of being is integral to Dasein from birth to death.
Homo faber perceives what is all around in the form of beings and based on learning and experience, understands immediately which are the ones that he or she can get hold of and make use of in a useful way. Sticks are useful in good quantities to start a fire which provides light and warmth and enables homo faber to cook and to gather and build bonds with other human beings. The way of homo faber ensures survival, upon which existence is dependent in a most fundamental way. Existence is continued existence – what in German is aptly called Fortbestand. Given Dasein‘s finitude, its continued existence, hence survival, can never be taken for granted, for the simple reason that it is not a metaphysical necessity. A species that cannot feed itself becomes extinct. Existence, and hence Dasein, is contingent upon what Heidegger describes in section ? in Being and time as the Zuhandenheit of beings in the world, the fundamental condition where being appropriates Dasein by granting access to the .
Hermeneutic understanding is made possible by death – the horizon of mortality as opposed to eternity. Yet death is not the now but is Dasein‘s potentiality-of-being (Seinkönnen) in the futural (zukünftige) thrownness (Geworfenheit) of its being-in-the-world.