What does it mean that existence precedes essence?

You are not born with a fixed purpose — you create your purpose through your choices.

Example: Marcus spent fifteen years as a corporate attorney because his parents, his professors, and his own early ambitions told him that law was his calling — his essence. When the firm restructured and he was laid off at forty-one, the identity collapsed. He was not a lawyer anymore, so who was he? For three months he spiraled, convinced that without the role he had lost himself. Then he began to notice something: the person sitting in the coffee shop every morning, reading philosophy, volunteering at a literacy nonprofit, writing essays about justice — that person was also him, and no one had assigned those activities. He was choosing them. The realization that he had always been choosing, even when he thought he was following a script, was the moment Sartre's insight became real for him. He had never been a lawyer by nature. He had been a person who chose law, and now he was a person choosing something else. The essence had never been fixed. It had always been under construction.

Try this: Write down three statements that complete the sentence "I am a ___" — using roles, identities, or labels you consider fundamental to who you are (e.g., "I am a teacher," "I am a creative person," "I am someone who values security"). For each one, write a second sentence that begins "I became this by ___" and trace the specific choices, circumstances, and actions that led to that identity. Then write a third sentence: "If I stopped ___, this identity would ___." Notice which identities depend on ongoing choices you are making right now and which ones you have been treating as fixed properties of your nature. The gap between "I am" and "I became this by choosing" is the territory Sartre mapped. Sit with it for ten minutes without trying to resolve the discomfort.