Central to Jean-Paul Sartre’s thinking is the view that people have no essential ‘essence’. In fact, when humans analyze their own being, what they find at the heart of it is nothing.

Yet this nothingness or lack of an essential self is a great thing. It means we are totally free to create the self or the life we want.

Being and Nothingness (1943) caught the mood of post-war France in which all the old certainties had crumbled away. If France’s existing value system had got it into such a mess in the War, was it worth anything?

Sartre represented a new way of seeing and being. People could choose their future, and despite Sartre’s weighty book being extremely difficult to read, the philosophy behind it excited a generation.

We are ‘abandoned’ in the universe, Sartre says: “Man is condemned to be free; because once thrown into the world, he is responsible for everything he does.” The person who realizes that they choose the meaning of their life, even if it is a frightening thought, is absolutely free.

They can live without excuses, regrets or remorse, and take absolute responsibility for their actions. “Success is not important to freedom”. You don’t have to attain what you have wished to be free, you just have to be free to make a choice.

We can’t escape our ‘facticity’ – the concrete facts of our existence like our sex, nationality, class, race. And yet, neither are we simply the sum of our facticity. Each of us can have a ‘project’ for our life.

The problem is that we shrink back from doing totally new things, things out of character, because we value consistency. Consistency is a form of security that makes sense of our world, but it is largely an illusion. 

Along with freedom comes responsibility. There are no accidents in life. Even if I find myself called up to fight in a war, and I long to get back to my normal life, I must still make it my war. By accepting, I regain my mental freedom.

We did not invent ourselves, or choose our own birth. All we can do is choose the meaning of our being, seeing every situation as an opportunity. To many people that’s a burden. They escape into ‘bad faith’ - lies they tell themselves to make things easier or more palatable.