The principal "No Exit" characters, Garcin, Estelle and Inez, are three people who start out with a veneer of civility to them despite their dire environs. Though each of them understands where they are (existentialist hell) and why they are there, they make an attempt at pleasant society. In Sartréan philosophy, existence precedes essence. The first principle of existentialism as explained by its creator, is this: Man is nothing else but that which he makes of himself or wills himself to be. It's a rephrasing of the old Cartesian maxim Cogito, Ergo Sum. ("I think, therefore I am.") Since Sartré's philosophy begins with the presumption of material atheism, there can be no one else to create/achieve your essence for you if you fail to do so yourself. No one else can take that role. An Existentialist is either born with what needs in order to self-actualize or not, in which case the absurdity of human existence destroys him. To miss the meaning of one's own life is to miss the meaning of all life, or so we might conclude here. To achieve existence is simply to be born, but to achieve essence is an act of the will. The power to determine one's own essence can be called the will to self. Garcin, Estelle, and Inez are fictitious example of those whom, in the playwright's opinion, failed as human beings because they lacked viable self-concepts. So, the Existentialist ideal (if there is such a thing) is definitely not what the play is meant to shows us. In "No Exit" We have three cogitos eternally without a sum. There is not one sum between them, nor is there one they can share. There is only irredeemable dysfunction and depravity playing itself out for all eternity.
Could you or I live in the country below the line
of despair if we simply retreated further and further into ourselves to keep from drowning? What is the final bulwark against despair if the entire universe is a Caucus Race [link] of absurdity? Existence precedes essences only in the solipsism of a hui-clos mind.
Existentialism is a Humanism Lecture 1946
Caucus Race from Alice In Wonderland