Existentialists think that what makes humans different from all other beings is the fact that we can choose what to do. In fact, we must choose: the only thing we are not free to do is not to be free. Other entities have some predefined nature: a rock, a penknife or even a beetle just is what it is. But as a human, there is no blueprint for producing me. I may be influenced by biology, culture and personal background, but at each moment I am making myself up as I go along, depending on what I choose to do next. As Sartre put it: “There is no traced-out path to lead man to his salvation; he must constantly invent his own path. But, to invent it, he is free, responsible, without excuse, and every hope lies within him.” It is terrifying, but exhilarating.
However tough it is, existentialists generally strive to be “authentic”. They take this to mean being less self-deceiving, more decisive, more committed, and more willing to take on responsibility for the world.
Most of the time, we don’t do this very well. Why? For Heidegger, the fault lies with our bewitchment by a non-entity called das Man, often translated as “the they” – as in “they say it will all be over by Christmas” (or the “one” in the phrase “one doesn’t do that”). We can’t say who exactly this “they” is, but it is everywhere, and it steals the decisions I should be making by myself.
For Sartre, the problem is mauvaise foi, or bad faith. To avoid facing up to how free I am, I pretend not to be free at all.