[M]an is condemned to be free. Condemned, because he did not create himself, in other respect is free; because, once thrown into the world, he is responsible for everything he does. The Existentialist does not believe in the power of passion. He will never agree that a sweeping passion is a ravaging torrent which fatally leads a man to certain acts and is therefore an excuse. He thinks that man is responsible for his passion.
Jean-Paul SartreThere are two kinds of existentialist; first, those who are Christian...and on the other hand the atheistic existentialists, among whom...I class myself. What they have in common is that they think that existence precedes essence, or, if you prefer, that subjectivity must be the turning point.
Jean-Paul Sartre