Summary of "Existentialism is a Humanism"

Core Idea

Existentialism starts from existence precedes essence: there is no fixed human nature given in advance, and a person becomes what they make of themselves.
In an atheistic world, there is no God, no prewritten human purpose, and no objective moral order that can be read off reality, so human beings are radically free and fully responsible.
Sartre defends this view as a humanism centered on action and self-making, not as pessimism, quietism, or moral chaos.

Sartre contrasts humans with artifacts like a paper-knife: the knife’s essence is planned before it exists, while the human being has no such blueprint.
If God does not exist, then there is no divine conception of man before man appears, so man first exists, encounters himself, and only afterward defines himself.
Human beings are not defined by inward wishes alone but by choices, acts, and commitments.
Sartre calls this human condition subjectivity: man is a project, always projecting himself toward a future and never reducible to a thing.
This does not make the person arbitrary in the sense of merely “wishing” oneself into being; it makes identity something one earns through lived action.

Because each choice helps define an image of humanity, every person is responsible for himself and for all men.
Anguish is the feeling produced by this burden, since one must ask what would happen if everyone acted as one does.
Sartre’s Abraham example shows that no external sign can remove responsibility: even if a voice or angel appears, the person must still decide whether it is truly authoritative.
Abandonment means there is no God, no a priori good, and no ready-made values to justify action from outside.
“Man is condemned to be free” because he did not create himself, yet must choose without final guarantees, excuses, or support.
Despair means limiting action to what depends on one’s own will and the probabilities directly relevant to action, rather than hoping for providence or distant rescue.
Sartre rejects excuses based on passion, circumstance, or signs, because even passion remains something for which the person is responsible.

Against quietism, Sartre says existentialism makes action central: there is no reality except in acting, and no hope except in what one does.
Against pessimism, he says the doctrine is severe optimism because it places human destiny inside the person rather than outside it.
Against individualism, Sartre says the cogito reveals not only oneself but also others, so self-knowledge is always mediated by other freedoms.
Human life is inter-subjectivity: each person exists in a world where other persons condition one’s own understanding and action.
Against the charge of arbitrariness or anarchism, Sartre insists that one always chooses in a situation, never in abstract freedom detached from necessity.
The student torn between his mother and the Free French illustrates that no moral code can settle concrete cases in advance.
Christian charity, Kantian ethics, and appeals to feeling all fail to decide the case because the values involved are too abstract and feelings are shaped by the deeds they are supposed to guide.
Sartre also rejects the idea that one can rely on the future actions of others as a moral guarantee, since one cannot count on humanity’s goodness or on history’s outcome.

Moral choice is like a work of art: there are no fixed aesthetic rules that determine the painting in advance, and likewise no a priori moral formula that determines the right act.
Bad faith hides freedom behind passions, determinants, or “signs,” while good faith acknowledges that one is choosing and cannot evade responsibility.
Sartre thinks one can judge others when they pretend to be necessary, fixed, or excused, because this denies the freedom that defines them.
The only universal morality that follows from existentialism is the will to freedom, and one cannot will one’s own freedom without willing the freedom of others.
Sartre rejects a false humanism that treats “Man” as a fixed supreme value or a ready-made essence, since this can slide into abstract cults of humanity and even Fascism.
His own humanism means that man is always outside himself, surpassing himself through projects, aims, and acts.
There is no universe except the human universe of subjectivity and transcendence, and human universality is not given but continually made through choices that others can understand across times and cultures.
The lecture’s final claim is that existentialism is not despair but the insistence that nothing will save us from ourselves, not even proof of God.

Existence precedes essence is the central formula: human beings are not born with a fixed nature or destiny.
Freedom is unavoidable, and its cost is anguish, because every choice has both personal and universal significance.
Ethics cannot be reduced to abstract rules, since real decisions are made in concrete situations without guaranteed guidance.
Sartre’s humanism is not admiration of “humanity” as an essence, but the claim that humans make themselves and thereby make an image of humanity for everyone.