Sartre–Heidegger on Humanism
*L'existentialisme est un humanisme* and the *Letter on Humanism*
Venue: Sartre, *L'existentialisme est un humanisme* (1946); Heidegger, *Brief über den Humanismus* (1947).
Heidegger's "Letter on Humanism" formally repudiates Sartre's reading of Heidegger as the father of existentialism.
In October 1945 Sartre delivered his lecture *L'existentialisme est un humanisme*, popularising existentialism and aligning it with Heidegger's *Being and Time* under the slogan "existence precedes essence." In 1947 Heidegger replied via Jean Beaufret's questions in the *Letter on Humanism*, decisively rejecting Sartre's reading. Heidegger held that humanism — including Sartrean existentialist humanism — remains caught within the very metaphysics of subjectivity Heidegger sought to overcome. Sartre had reduced Heidegger's ontological project to an ethical-anthropological doctrine. The *Letter* signals Heidegger's post-war "turn" (*Kehre*) away from his earlier existential analytic toward a thinking of Being and language, and inaugurates the continental philosophy of the second half of the 20th century.
Historical Context
Heidegger had been suspended from teaching by the French occupying authorities for his Nazi affiliations; Sartre was at the peak of his fame in liberated Paris. Heidegger's repudiation of Sartre is partly a recovery of his own philosophical project against a popular misreading, partly a strategic positioning post-war.
Parties
There is no human essence; man defines himself through free choice and projects. Existence precedes essence. Existentialism is a humanism because it places the dignity of free human choice at the centre.
Key arguments
- No God to fix a human essence; therefore the human being is "condemned to be free."
- Authenticity: taking up one's freedom and responsibility, refusing bad faith.
- Universality: in choosing for oneself, one chooses (implicitly) for all humanity.
- Practical political engagement follows from existential freedom; existentialism is not solipsistic.
Allied schools
Sartre's formulation remains within the humanist-metaphysical tradition Heidegger's work sought to overcome. The question is not "what is the human?" but "what is Being, and how does the human belong to Being?"
Key arguments
- Sartre inverts but preserves the essence/existence pair; the ontological question is more radical than either pole.
- Humanism elevates the human at the cost of forgetting Being; this is the central failure of Western metaphysics.
- Language is "the house of Being"; thinking must be a listening to the saying of Being, not a project of human self-assertion.
- Ethics in the metaphysical sense follows from the prior question of Being; without it, ethics is groundless.
Allied schools
Dimensions Engaged
Observer
Observer · Physicality and Agency: the constitution of the human, between humanist self-assertion and a more radical thinking of Being.
Verdict in retrospect
The two thinkers continued to be read in their own right; neither displaced the other. The continental philosophy of the second half of the 20th century — Levinas, Derrida, Lacan, Foucault, Marion — develops in Heidegger's wake more than Sartre's, but existentialism's broader humanist register has persisted in political and ethical thought.
Related Debates
Sharing parties or aligned schools.
Related Experiments
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Other Personas Aligned With This Debate
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Related Contemporary Dilemmas
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Further reading
- Sartre, *Existentialism is a Humanism* (1946; tr. Macomber 2007)
- Heidegger, *Letter on Humanism* (1947; in *Pathmarks*, 1998)
- Crowell (ed.), *Cambridge Companion to Existentialism* (2012)