Jean-Paul Sartre’s philosophy: one of the most influential and complex systems in 20th-century thought.
🧠 1. Who Was Jean-Paul Sartre?
Born: 1905, Paris
Died: 1980
Major works:
Being and Nothingness (1943) — main philosophical treatise
Nausea (1938) — existential novel
No Exit (1944) — play (famous line: “Hell is other people.”)
Existentialism Is a Humanism (1946) — accessible lecture clarifying his philosophy
Sartre was a philosopher, novelist, playwright, and political activist who helped shape existentialism and phenomenology in modern thought.
🔍 2. Core Idea: Existence Precedes Essence
This is Sartre’s most famous principle.
He flips centuries of philosophy on its head.
What it means:
Traditional thought (e.g., Aristotle, Christianity): Essence precedes existence → a human’s purpose or nature is defined before birth (by God, nature, or reason).
Sartre: there is no pre-given human nature. We exist first, and only later define ourselves through choices.
“Man first of all exists, encounters himself, surges up in the world—and defines himself afterwards.”
Implication:
We are radically free — completely responsible for giving our lives meaning.
There is no divine blueprint, no fixed morality, no destiny.
⚡ 3. Radical Freedom and Responsibility
Freedom is not a gift — it’s a burden.
Since there’s no external guide (God, moral law, human nature), every decision we make creates our values.
We are condemned to be free — because even refusing to choose is itself a choice.
Consequence:
We realize that nothing dictates what we should do; the weight of creation is on us.
Freedom → Responsibility
Our choices define not only us but what we think all humans should be.
(“In choosing for myself, I choose for all mankind.”)
🌀 4. Consciousness, Being, and Nothingness
In Being and Nothingness, Sartre distinguishes two modes of being:
1. Being-in-itself (en-soi)
The being of things (rocks, tables).
Solid, complete, self-contained.
Has no consciousness.
2. Being-for-itself (pour-soi)
The being of consciousness.
Defined by negation, it is what it is not and is not what it is.
Always questioning, projecting, imagining possibilities.
Incomplete, in flux, this is us.
Nothingness:
Consciousness introduces “nothingness” into the world, the ability to negate, to imagine “what is not.”
That’s why humans can change, create, and rebel.
🎭 5. Bad Faith (Mauvaise foi)
Since freedom is heavy, humans often lie to themselves to escape it.
Bad faith = self-deception; pretending we have no choice.
Example:
A waiter acts only as a waiter, denying his freedom to be more.
A woman on a date pretends not to notice a man’s romantic advances to delay choosing a response.
Sartre’s insight:
We try to be both object (thing with a fixed essence) and subject (free consciousness).
But that’s impossible ... it’s self-deception.
👁️ 6. “Hell Is Other People”
From No Exit, this famous line is often misunderstood.
Sartre doesn’t mean that all relationships are hellish
He means that when we become dependent on others’ judgment, we become trapped.
Others turn us into an object (“the look” le regard),
And we lose our subjectivity.
So, hell is being frozen by another’s gaze, unable to define ourselves freely.
🌍 7. Existential Humanism
Sartre’s existentialism is not nihilism.
Though there’s no God, it doesn’t mean life is meaningless.
Instead, meaning is something we create.
Existentialism becomes a call to action — to live authentically and responsibly.
“Man is nothing else but what he makes of himself.”
⚙️ 8. Political and Ethical Dimension
Later in life, Sartre combined existentialism with Marxism — trying to reconcile personal freedom with social structures.
He argued:
Freedom must operate within real social conditions (poverty, oppression limit freedom).
True freedom involves changing society to expand freedom for all.
He became an activist — opposing colonialism, supporting workers’ rights, and rejecting the Nobel Prize to stay independent.
📚 9. Sartre vs. Other Thinkers
Thinker Contrast with Sartre
Nietzsche Both reject God and essence; Nietzsche celebrates power and creativity, Sartre stresses moral responsibility.
Heidegger Sartre borrowed Being-in-the-world ideas but focused more on human freedom and ethics, less on ontology.
Camus Camus saw life as absurd and advocated revolt without meaning; Sartre believed we can still create meaning.
Simone de Beauvoir Sartre’s lifelong partner — extended existentialism into feminism (The Second Sex).
💡 10. Key Takeaways
There is no predefined human nature — we invent ourselves.
Freedom is absolute, but it brings anxiety and responsibility.
We fall into bad faith when we deny our freedom.
Authenticity means owning our choices.
Others’ perception shapes but shouldn’t define us.
Meaning is not discovered — it’s created.
✍️ Sartre in One Quote
“Every existing thing is born without reason, prolongs itself out of weakness, and dies by chance.” — Nausea
Yet — within that absurdity, we are free to define meaning.