What is existentialism?

Existentialism is a philosophical school of thought that was born around the 1950s.Existentialists stress the importance of choices. Contrary to moral supernaturalism and nihilism, existentialism puts forward the idea that only we can decide what our life purpose is. In other words, no other being or force can decide for us: it is completely up to us."We are left alone, with no excuse." (Jean-Paul Sartre)One of the most important concepts in existentialism is authenticity. To be authentic, or to lead an authentic life, is to make choices on our own and not to follow other people's believes or lifestyles. An authentic life is one that is chosen purely by the individual himself or herself, and not by an outside force.