What Is Existentialism? Heidegger, Being and Time, and Dasein

What is existentialism, and who was Heidegger

Existentialism is the twentieth-century current of philosophy centered on individual existence, freedom and the search for meaning. The Stanford Encyclopedia of Philosophy names one thinker above all as its shaping force: the German philosopher Martin Heidegger, born on 26 September 1889 in Meßkirch, in Baden, in southwestern Germany, and died on 26 May 1976 in Freiburg - even though Heidegger spent decades trying to shrug the label off.

Readers who come to Heidegger from Kierkegaard’s Either/Or or from Hegel’s Phenomenology of Spirit will recognize familiar ground: the question of what it means to exist, not just what exists. Heidegger approaches it from a new angle, asking what it means to be, before asking what things there are in the world.

Being and Time

Heidegger’s major work is Being and Time (Sein und Zeit), published in February 1927. Treccani calls it his most important book, and the Stanford Encyclopedia notes that it remained unfinished relative to the project that produced it: the part meant to carry it forward was never published in the form originally planned.

The book opens with a single question: what does it mean to be? Heidegger does not ask it of ordinary objects, but of the one entity capable of asking it at all.

Real-world example: think of a parked car and the driver sitting inside it. The car simply sits there, running or not, without any stake in the matter. The driver, by contrast, can wonder whether driving to work every day is the life she actually wants - and in that act of wondering about her own existence, she is doing exactly what Heidegger means by understanding one’s own being.

Dasein

The term Heidegger uses for the human being is Dasein, often rendered in English as “being-there.” The Stanford Encyclopedia, the Internet Encyclopedia of Philosophy and Treccani agree on one precise point: Dasein is not simply one entity among others, the way a stone or a table is. It stands apart from every other entity because it puts its own existence into question, and because it always carries at least a preliminary understanding of what it means to be.

That starting point sets Heidegger apart from other major philosophical systems that ask first what we can know, such as Kant’s Critique of Pure Reason. His question sits a step earlier than Kant’s: whoever knows anything is already, from the start, an entity questioning its own existence.

Existentialism: the label he refused

According to the Stanford Encyclopedia of Philosophy and the Internet Encyclopedia of Philosophy, Heidegger’s thought shaped Jean-Paul Sartre’s existentialism (the Internet Encyclopedia also mentions Ortega y Gasset). Yet in 1946, in the Letter on Humanism (Brief über den Humanismus), Heidegger distanced himself from those readings of his work and argued openly against Sartre, positioning himself against every form of humanism, which he regarded as still bound to metaphysics.

The irony is hard to miss: the pages of Being and Time on Dasein fed an entire philosophical movement, yet the author of those pages later refused to be counted among its members, in a letter written for that very purpose. Readers tracing the existentialist root further back find related, if methodologically distinct, ground in Kierkegaard’s Fear and Trembling, where the individual’s leap in the face of the paradox of faith anticipates, from a religious angle, some of the questions Heidegger later poses in philosophical terms.

Freiburg, 1933

Shortly after Hitler’s rise to power, Heidegger was elected rector of the University of Freiburg in April 1933, and on 1 May of that same year he joined the Nazi party, remaining a member until the regime collapsed. This is a documented historical fact reported by the Stanford Encyclopedia of Philosophy, which also notes that after the war Heidegger repeatedly denied or minimized the real extent of his political involvement. The sources gathered here do not explain his personal reasons for that choice, nor do they draw a direct line from it to the philosophical content of Being and Time, published years earlier. What remains is the fact of the membership, its duration, and his later denials and minimizing of it: an episode central to historical assessments of his life. Historians continue to weigh his claims about being and Dasein on their own terms, judging the arguments for what they say.