For now, in the immediate wake of the war, he promoted an “existentialist” humanism based on the idea that each of us is radically free and responsible for our actions. Sartre’s humanism was a tough-guy version made for the 1940s; it was also genuinely non-religious. It rested on the idea that humans have no preexisting blueprint for our nature, divine or otherwise. It is up to us what we make of ourselves; we must, individually and at every moment of choice, “invent man.”