Heidegger, Martin (1889–1976)
Authors: Sheehan Thomas 
Published: September 2018

Martin Heidegger taught philosophy at Freiburg University (1915–23), Marburg University (1923–8), and again at Freiburg University (1928–45). Early in his career he came under the influence of Edmund Husserl, but he soon broke away to fashion his own philosophy. His most famous work, Sein und Zeit (Being and Time) was published in 1927. Heidegger’s energetic support for Hitler in 1933–4 earned him a suspension from teaching from 1945 to 1950. In retirement he published numerous works, including the first volumes of his Collected Edition. His thought has had strong influence on trends in philosophy ranging from existentialism through hermeneutics to deconstruction, as well as on the fields of literary theory and theology.
Heidegger often makes his case in charged and dramatic language that is difficult to convey in summary form. He argues that mortality is our defining moment, that we are thrown into limited worlds of sense shaped by our being-towards-death, and that finite meaning is all the reality we get. He claims that most of us have forgotten the radical finitude of ourselves and the world we live in. The result is the planetary desert called nihilism, with its promise that an ideally omniscient and virtually omnipotent humanity can remake the world in its own image and likeness. None the less, he still holds out the hope of recovering our true human nature, but only at the price of accepting a nothingness darker than the nihilism that now ravishes the globe. To the barely whispered admission, ‘I hardly know anymore who and where I am’, Heidegger answers: ‘None of us knows that, as soon as we stop fooling ourselves’ ([1959a] 1966: 62).
Yet he claims to be no pessimist. He merely wants to find out what being as such means, and Being and Time was an attempt at this. He called it a fundamental ontology: a systematic investigation of human being (Dasein) for the purpose of establishing the meaning of being in general. Only half of the book – the part dealing with the finitude and temporality of human being – was published in 1927. Heidegger elaborated the rest of the project in a less systematic form during the decades that followed.
Heidegger distinguishes between an entity (anything that is) and the being of an entity. He calls this distinction the ‘ontological difference’. The being of an entity is the meaningful presence of that entity within the range of human experience. Being has to do with the ‘is’: what an entity is, how it is, and the fact that it is at all. The human entity is distinguished by its awareness of the being of entities, including the being of itself. Heidegger names the human entity ‘Dasein’ and argues that Dasein’s own being is intrinsically temporal, not in the usual chronological sense but in a unique existential sense: Dasein ek-sists (stands-out) towards its future. This ek-sistential temporality refers to the fact that Dasein is always and necessarily becoming itself and ultimately becoming its own death. When used of Dasein, the word ‘temporality’ indicates not chronological succession but Dasein’s finite and mortal becoming.
If Dasein’s being is thoroughly temporal, then all of human awareness is conditioned by this temporality, including one’s understanding of being. For Dasein, being is always known temporally and indeed is temporal. The meaning of being is time. The two main theses of Being and Time – that Dasein is temporal and that the meaning of being is time – may be interpreted thus: being is disclosed only finitely within Dasein’s radically finite awareness.
Heidegger arrives at these conclusions through a phenomenological analysis of Dasein as being-in-the-world, that is, as disclosive of being within contexts of significance. He argues that Dasein opens up the arena of significance by anticipating its own death. But this event of disclosure, he says, remains concealed even as it opens the horizon of meaning and lets entities be understood in their being. Disclosure is always finite: we understand entities in their being not fully and immediately but only partially and discursively; we know things not in their eternal essence but only in the meaning they have in a given situation. Finite disclosure – how it comes about, the structure it has, and what it makes possible – is the central topic of Heidegger’s thought. ‘Time is the meaning of being’ was only a provisional way of expressing it.
Dasein tends to overlook the concealed dimension of disclosure and to focus instead on what gets revealed: entities in their being. This overlooking is what Heidegger calls the forgetfulness of the disclosure of being. By that he means the forgetting of the ineluctable hiddenness of the process whereby the being of entities is disclosed. He argues that this forgetfulness characterizes not only everyday ‘fallen’ human existence but also the entire history of being, that is, metaphysics from Plato to Nietzsche. He calls for Dasein resolutely to reappropriate its own radical finitude and the finitude of disclosure, and thus to become authentically itself.