Even non-human animals mostly follow the instincts and behaviours that characterize their species, Sarte believed. But as a human being, I have no predefined nature at all. I create that nature through what I choose to do. Of course I may be influenced by my biology, or by aspects of my culture and personal background, but none of this adds up to a complete blueprint for producing me. I am always one step ahead of myself, making myself up as I go along.
Sarah Bakewell, At the Existentialist Café