JEAN-PAUL SARTRE

…All I know is I'm going to do everything in my power to bring it about. Beyond that, I can't count on anything. Quietism is the attitude of people who say, "Let others do what I can't do." The doctrine I am presenting is the very opposite of quietism, since it declares, "There is no reality except in action." Moreover, it goes further, since it adds, "Man is nothing else than his plan; he exists only to the extent that he fulfills himself; he is therefore nothing else than the ensemble of his acts, nothing else than his life."

Existentialism and Human Emotions