and can be changed by choosing differently in the present, but such changes happen slowly. They are a force of inertia that shapes the agent's evaluative outlook on the world until the transition is complete.

Sartre's definition of existentialism was based on Heidegger's magnum opus Being and Time (1927). In the correspondence with Jean Beaufret later published as the Letter on Humanism, Heidegger implied that Sartre