"Being and Nothingness" by Jean-Paul Sartre,1956

Being and Nothingness: An Essay on Phenomenological Ontology,sometimes subtitled A Phenomenological Essay on Ontology,is a 1943 philosophical treatise by Jean-Paul Sartre. Its main purpose was to define consciousness as an act of negation (a transcendence of the given world).
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“ 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.
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The origin of negation
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."[4] So Sartre claims "It is evident that non-being always appears within the limits of a human expectation."
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Bad faith
Bad faith or "Self-Deception", as translations vary, can be understood as the guise of existing as a character, individual or person who defines himself through the social categorization of his formal identity. This essentially means that in being a waiter, grocer, etc. one must believe that his or her social role is equivalent to his or her human existence. Living a life defined by one's occupation, social, racial or economic class, is the very faith of "bad faith", the condition in which people cannot transcend their situations in order to realize what they must be (human) and what they are not (a grocer, etc). It is also essential for an existent to understand that negation allows the self to enter what Sartre calls the "great human stream". The great human stream arises from a singular realization that nothingness is a state of mind in which we can become anything, in reference to our situation, that we desire.
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 differ vastly with regard to human identity.
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 that his or her existence and his 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, and thus we are subject to playing our lives out in a similar manner. An example is something that is what it is (existence) and something that is what it is not (a waiter defined by his occupation).
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. This 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 Dostoevsky's Notes from Underground. Dostoevsky has been called "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. Being a "moral person" requires one to deny authentic impulses (everything that makes us human), and allow the will of another person to change one's actions. 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 one's existence. Sartre has a very low opinion of conventional morality, condemning it as a tool of the bourgeoisie to control the masses. Examples include a "Keep Off The Grass" sign, which derives its being from a bourgeois need but hinders the need of the masses for play and relaxation.
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).
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The look
The mere possible presence of another person causes one to look at him/herself as an object, and see his/her world as it appears to the other. This is not done from a specific location outside oneself, it is non-positional. This is a recognition of the subjectivity in others.
This transformation is most clear when one sees a mannequin that one confuses for a real person for a moment.
While they are believing it is a person, their world is transformed, and everything exists as an object that partially escapes them. During this time the world comes on to you differently, and you can no longer have a total subjectivity. The world is now his world, a foreign world that no longer comes from you, but from him. The other person is a "threat to the order and arrangement of your whole world…Your world is suddenly haunted by the Other's values, over which you have no control."
When they realise it is a mannequin, and is not subjective, the world seems to transfer back, and they are again in the center of a universe.
This is back to the pre-reflective mode of being, it is "the eye of the camera that is always present but is never seen".The person is occupied, and too busy for self-reflection.
This process is continual, unavoidable and ineluctable. Subjectivity is competitive. This explains why it can be difficult to look someone in the eye.
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