A defense addressed to a public audience
On the evening of 29 October 1945, Jean-Paul Sartre spoke at the Salle des Centraux on Paris’s Right Bank about existentialism and humanism. Already known for Nausea, No Exit and Being and Nothingness, he faced a packed audience. Philosophical historian Thomas Flynn notes that many treated the lecture as a manifesto for a movement gaining popularity.
The lecture identifies its opponents directly. Communists charged that existentialism remained trapped in individual consciousness and could not adequately explain solidarity and action. Christian critics argued that removing God-given values made morality arbitrary. Sartre organized his talk as successive answers to accusations of pessimism, passivity and irresponsibility.
Explaining the human condition with a paper knife
The text’s best-known proposition is that existence precedes essence. Sartre compares human life with a paper knife: before making it, a craftsperson knows its purpose and method of manufacture. Human lives, by contrast, do not unfold according to an already completed specification. In Sartre’s atheist account, people enter the world and then form themselves through action.
He closely connects this freedom with responsibility. Choosing a way of life endorses an image of humanity with implications beyond private preference. Decisions produce anguish because no external rule can take over the final judgment, and action also affects other people. His argument places demands on freedom rather than treating it as unrestricted preference.
References: [1]
A student faced with an unavoidable choice
Sartre makes the abstract question concrete with a student’s dilemma. His elder brother had died in the war in 1940, and his mother depended on him. He wanted both to stay with her and to travel to Britain to join the Free French. The first choice offered direct but limited help; the second served a broader aim but might be frustrated by travel, detention or work assignments.
General principles such as loving one’s neighbor or treating people as ends could not automatically rank these alternatives. Feelings acquired weight through action, and deciding whom to consult was itself a choice. Sartre did not announce a correct answer for the student. The example illustrates why a moral decision cannot be delegated entirely to a formula or an authority.
References: [1]
Connecting freedom with other people
Answering the charge that existentialism produced inactivity, Sartre explained despair as reliance on one’s own action and relevant real possibilities, without waiting for history or providence to guarantee success. He called for commitment without guarantees and rejected the substitution of unrealized talents and dreams for actual life.
The ending distinguishes two kinds of humanism. Sartre rejects elevating humanity on the strength of a few great achievements, while arguing that people become human by going beyond themselves toward particular goals. Seeking one’s own freedom also concerns the freedom of others. The conclusion reconnects the opening dispute over isolated individuals with shared life.
References: [1]
The 1946 book and subsequent editions
Nagel published the lecture the next year as L’existentialisme est un humanisme. The BnF’s copy of the seventh edition in the Pensées series, dated 1946, provides a concrete record of its rapid entry into print. The 1945 lecture and the 1946 book were separate stages, and an edition number cannot by itself establish sales.
A short, accessible book gave the lecture’s formulas and everyday examples a life beyond the meeting hall. Philip Mairet’s translation was later included in Walter Kaufmann’s Existentialism from Dostoyevsky to Sartre, placing the French lecture alongside other authors. The opening rebuttals, paper knife and student story remained available as routes into its argument.
Circulation brought further objections
This popular defense did not settle the disagreements. In Letter on “Humanism,” Heidegger directly addressed Sartre’s central formula. In his view, reversing the priority of essence and existence still remained within traditional metaphysics. He sought to question being itself, beyond changing the order of the two concepts. His explicit reference to Sartre’s short book shows its role in philosophical debate.
Flynn’s biographical preface notes that the widely used introduction was also a text Sartre publicly regretted publishing. Its importance lies both in broadening the audience for existentialism through concise examples and in placing unresolved difficulties between responsibility, freedom and humanism before critics.