Being and Nothingness: An Essay on Phenomenological Ontology (French: L'Être et le néant : Essai d'ontologie phénoménologique), sometimes subtitled A Phenomenological Essay on Ontology, is a 1943 philosophical treatise by Jean-Paul Sartre that is regarded as the beginning of the growth of existentialism in the 20th century. Its main purpose was to define consciousness as transcendent.
Sartre’s overriding concern in writing Being and Nothingness was to vindicate the fundamental freedom of the human being, against determinists of all stripes. It was for the sake of this freedom that he asserted the impotence of physical causality over human beings, that he analysed the place of nothingness within consciousness and showed how it intervened between the forces that act upon us and our actions.
When we go about the world, we have expectations which are often not fulfilled. For example, Pierre is not at the café where we thought we would meet him, so there is a negation, a void, a nothingness, in the place of Pierre. When looking for Pierre his lack of being there becomes a negation; everything he sees as he searches the people and objects about him are "not Pierre. So Sartre claims "It is evident that non-being always appears within the limits of a human expectation."
The possibility of playing is afforded by time and situation. It isn't difficult to see how Sartre's ideas are linked to post-modernist/structural claims offered by Michel Foucault. However, the theories, in regard to human identity are vastly different.
In any light, the difference in existence and identity projection remains at the heart of human subjects who are swept up by their own condition, their "bad faith". One of the most widely discussed examples of projection (via Freud's conception of the human mind) that Sartre uses is the café waiter who performs the duties, traditions, functions and expectations of a cafe waiter.
"[W]hat are we then if we have the constant obligation to make ourselves what we are if our mode of being is having the obligation to be what we are? Let us consider this waiter in the cafe. His movement is quick and forward, a little too precise, a little too rapid. He bends forward a little too eagerly; his voice, his eyes express an interest a little too solicitous for the order of the customer. Finally there he returns, trying to imitate in his walk the inflexible stiffness of some kind of automaton while carrying his tray with the recklessness of a tight-rope-walker by putting it in a perpetually unstable, perpetually broken equilibrium which he perpetually re-establishes by a light movement of the arm and hand. All his behavior seems to us a game. He applies himself to changing his movements as if they were mechanisms, the one regulating the other; his gestures and even his voice seems to be mechanisms; he gives himself the quickness and pitiless rapidity of things. He is playing, he is amusing himself. But what is he playing? We need not watch long before we can explain it: he is playing at being a waiter in a cafe. There is nothing there to surprise us."
Sartre consistently mentions that in order to get out of bad faith, one must realize their existence, and their formal projection of a self are distinctly separate and within the means of human control. This separation is a form of nothingness. Nothingness, in terms of bad faith, is characterized by Sartre, as the internal negation which separates pure existence and identity as something that is what it is (existence) and something that is what it is not (a waiter defined by his occupation) and thus we are subject to playing our lives out in a similar manner.
Yet, Sartre takes a stance against characterizing bad faith in terms of "mere social positions"; I am never any one of my attitudes, any one of my actions. The good speaker is the one who plays at speaking because he cannot be speaking. Which literally means that, like the cafe waiter, the speaker is not his condition or social categorization, but is a speaker consumed by bad faith. Thus, we must realize what we are (beings who exist) and what we are not (a social, historical, preoccupation) in order to step out of bad faith. Yet, existents (human beings) must maintain a balance between existence, their roles and nothingness to become authentic beings.''
Additionally, an important tenet of bad faith is that we must enact a bit of good faith in order to take advantage of our role to reach an authentic existence. The authentic domain of bad faith, is realizing that the role we are playing is the lie. The goal of authenticity can be traced back to the works of Dostoevsky's Notes from Underground who is often declared "The Grandfather of existentialism". To live and project into the future as a project of a self, while keeping out of bad faith and living by the will of the self is living life authentically. This is perhaps one of the main goals of Sartre's opus.
One of the most important implications of bad faith is the abolition of traditional ethics and morality. As being a "moral person" requires one to deny authentic impulses (everything that makes us human) and change one's actions on the will of another person. Being a moral person is one of the most severe forms of bad faith. Essentially Sartre characterizes this as "the faith of bad faith" which is and should not be, in Sartre's opinion, at the heart of their existence. Sartre has a very low opinion of conventional morality for this reason, condemning it as a tool of the bourgeoisie to control the masses. Examples such as signs that say "Keep Off The Grass" deriving "its being from its exigency and not its exigency from its being."
Bad faith also results when individuals begin to view their life as made up of distinct past events, like the "perfect moments" or "adventures" from Nausea. By viewing one's ego as it once was rather than as it currently is, one ends up negating the current self and replacing it with a past self that no longer exists (as illustrated by Anny in Nausea).
This transformation is most clear when one sees a mannequin that one confuses for a real person for a moment.
This process is continual and unavoidable. Subjectivity is competitive. This explains why it can be difficult to look someone in the eye. Sartre does mention another man in the park who is reading a newspaper. This man is different because he is so engaged in a project, that he allows himself to be completely the object- "a man reading".
Sartre states that many relationships are created by people's attraction not to another person but rather how that person makes them feel about themselves by how they look at them. This is a state of emotional alienation whereby a person avoids experiencing their subjectivity by identifying themselves with "the look" of the other. "The look" of the other found the person's own being. The consequence is conflict. In order to keep the persons own being the person must control the other but must control the freedom of the other "as freedom". These relationships are a profound manifestation of "Bad faith" as the for-itself is replaced with the others freedom. The purpose of the participants is not to exist but to keep the other participant looking at them. This system is often mistakenly called love but is in fact nothing more than emotional alienation and a denial of freedom through conflict with the other. Sartre believes that it is often created as a means of making the unbearable anguish of a person's relationship to their "Facticity" (all of the concrete details against the background of which human freedom exists and is limited, such as birthplace and time) bearable. At its extreme the alienation can become so intense that due to the guilt of being so radically enslaved by "the look" and therefore radically missing their own freedoms the participants can enter into masochistic and sadistic attitudes. This happens when the participants even cause pain to each other to try to prove their control over the other's look which they cannot escape because they believe themselves so enslaved to the look that experiencing their own subjectivity would be equally unbearable.

Even in sex (perhaps especially in sex), men and women are haunted by a state in which consciousness and bodily being would be in perfect harmony, with desire satisfied. Such a state, however, can never be. We try to bring the beloved's consciousness to the surface of her/his body by use of magical acts performed, gestures (kisses, desires). But at the moment of orgasm the illusion is ended and we return to ourselves, just as it is ended when the skier comes to the foot of the mountain or when the commodity that once we desired loses its glow upon our purchase of it. There will be, for Sartre, no such moment of completion because "man is a useless passion" to be the ens causa sui, the God of the ontological proof.
It is this dichotomy that causes anguish, because choice (subjectivity) represents a limit on freedom within an otherwise unbridled range of thoughts. Subsequently, humans seek to flee our anguish through action-oriented constructs such as escapes, visualizations or visions (dreams) designed to lead us toward some meaningful end, such as necessity, destiny, determinism (God), etc.
Thus, in living our lives, we often become unconscious actors — Bourgeois, Feminist, Worker, Party Member, Frenchman, Canadian or American — each doing as we must to fulfill our chosen characters' destinies.
But again, Sartre contends, our conscious choices, leading to often unconscious actions, run counter to our intellectual freedom. Yet we are bound to the conditioned, physical world — in which some form of action is always required. This leads to failed dreams of completion, as Sartre described them, because inevitably we are unable to bridge the void between the purity and spontaneity of thought and all-too constraining action; between the being and the nothingness that inherently coreside in our self.
Yet Sartre's recipe for fulfillment is to escape all quests by completing them, by rigorously forcing order onto nothingness, using terms such as the "spirit (or consciousness of mind) of seriousness" and describing the failure to do so in terms such as "bad faith" and "false consciousness." Though Sartre's conclusion seems to be that being pales before nothingness, since consciousness is probably based more on spontaneity than on stable seriousness, he contends that any person of a serious nature is obligated to continuous struggle between:
a) the conscious desire for peaceful self-fulfillment through physical actions and social roles — as if living within a portrait that one actively paints of oneself (see the gallery of Bouville's notables in Nausea), and
b) the more pure and raging spontaneity of no thing consciousness, of being instantaneously free to overturn one's roles, pull up stakes, and strike out new paths.
Explanation of terms based on postscript to the English edition of Being and Nothingness by translator Hazel Barnes
Thus, for Sartre's Garcin, in No Exit, "hell is other people."
There is a second, comical reference. When explaining the difference between existence and essence, Sartre uses a paper-knife (un coupe-papier). A paper-knife also appears as a crucial prop in No Exit.
There could be no radical utopian experiments for early Sartre. Nor could there be the platitudes of liberal or conservative world-views. Sartre carries this "hyperempiricism" into his later work, and the fellow-travelling Sartre of the 1950s and after seems almost to forget the Sartre of the 1940s, and it would not be until “'The Family Idiot”, his “existential psychoanalysis” of Gustave Flaubert that Sartre would attempt to bring together his existentialist and Marxist views.