In existentialism, the ethical ideal is to live "authentically"–a notoriously slippery concept—celebrating individual freedom and responsibility.  According to Sartre, we are here by blind chance, and nothing more.  There is no objective reason for our existence, and this hard truth imposes a responsibility on each of us to live "authentically" by creating our own meaning and purpose.  For Sartre, too often, we allow others to dictate the choices we make and the values by which we live, instead of being authentically who we are. 

Sartre's distinctive ethical approach marks a significant departure from traditional moral theories, which focus on the duties we have to others rather than to ourselves. Indeed, many have criticized existentialism on this basis as an ethically bankrupt philosophy justifying selfish indulgence at the expense of others.  As demonstrated in the biographical film you watched, Sartre—who infamously proclaimed at one point that "hell is other people"– struggled throughout his life to balance his individualist philosophy with social responsibilities.   

What do you make of the existentialist ideal of authenticity?  Is it morally beneficial or harmful?  Can we live authentically with others?