Existentialism Is a Humanism: Summary & Key Insights

The phrase 'existence precedes essence' has become almost a slogan of existentialism, but it bears careful interpretation. When I say this, I mean that there is no predefined nature, no divine blueprint, that determines what a human being is. Unlike a manufactured object—a paper cutter, for example—that is designed with a specific purpose before it exists, human beings appear in the world first, then must define themselves afterward through action.

This reversal of traditional metaphysics is the foundation of existential thought. Philosophers before me, from Aristotle to Descartes, assumed that essence—the set of defining characteristics—comes first. Man was defined by a rational soul, by a moral purpose, or by a place in the cosmic order. Existentialism overturns this by insisting that humans simply find themselves existing, and only afterward construct a self through choice. In a universe emptied of divine instruction, the responsibility of self-definition rests entirely on our shoulders.

This idea terrifies many because it abolishes excuses and external authorities. If there is no God, no inherent nature, we cannot say, 'I was born to this,' or, 'That was my destiny.' It means that at every moment, we are choosing—and through those choices, we declare what we believe a human being should be. When I act, I am at once defining myself and shaping the model of humanity as a whole.

This is why existentialism refuses the comfort of essentialist thinking. It forces us to confront an unstructured life, a blank canvas, and asks us to paint upon it with our own decisions. That is not despair—it is liberation. It is an affirmation that life’s meaning, if it exists at all, must be made, not found.

Determinism is a seductive doctrine—it suggests that everything is written, that human beings are products of circumstance, biology, or divine will. But existentialism rejects such notions outright. I argue that man is radically free, because the absence of any predetermined essence implies that nothing constrains our capacity to choose, save for the physical limits of our situation.

This freedom is not metaphysical license but lived reality. Even in the most constrained conditions, even under oppression or imprisonment, man remains free to interpret, to decide, to act. Freedom is not the ability to get what one wants but the responsibility to choose one’s response to what is. Once we remove determinism, accountability returns. You cannot hide behind 'nature' or 'fate'; you are responsible for your own acts and, by extension, for the shape of humanity those acts express.

Of course, this rejection of determinism makes life difficult. Many would prefer a God who commands, a nature that dictates, a society that molds us. To be free is to stand naked before a silent universe, to realize there is no external justification for your existence. But precisely here lies the source of human dignity. You become the author of your being.

When critics accuse existentialism of being cold and individualistic, they misunderstand its moral heart. By affirming freedom, I am not isolating man—I am reminding him that every choice ripples outward, touching others and shaping the shared world. Freedom is therefore never private; it is a universal condition of human existence. To act freely is to accept the weight of humanity in one’s hands.