We do not thrive in satiety and rest. Human existence means ‘transcendence’, or going beyond, not ‘immanence’, or reposing passively inside oneself. It means constant action until the day one runs out of things to do — a day that is unlikely to come as long as you have breath. For Beauvoir and Sartre, this was the big lesson of the war years: the art of life lies in getting things done.