Introduction to Philosophy/Existentialism
<-- I have not the time now but I recommend adding Nietzsche's "proto"-existential viewpoint which was neither one of "nausea" or "apathy" --> <-- Indeed, he even says that many people are not existential and are mere skeletons who have shrouded themselves with the beliefs of others. -->
Have you ever felt that "hell is other people"?
Do you think you are "condemned to be free" because you make your own choices in life, and are not dependent on external morality?
If so, you may be an existentialist.
One existentialist thought is "Nothing is true, everything is permitted". Fyodor Dostoevsky expressed this through Ivan, a character in his book The Brothers Karamazov (Братья Карамазовы). Ivan later shed his existentialism for faith in God (misquoted by Sartre in Existentialism is a Humanism).
One existentialist feeling is nausea, another is apathy. Both feelings are in response to not actually being able to change the world.
The "first" existentialist (or at least the first to bear this title of "existentialist") was Søren Aabye Kierkegaard, a Danish philosopher. He talked about three stages in our lives:
- the aesthetic stage,
- the religious stage, and
- the existential or enlightened stage.
These three stages were commonly associated with the "feelings" that accompanied them.
The aesthetic stage, embodied by young people who recklessly pursue youth's pleasures or by students of science or another devotion which requires great discipline in which to achieve success, is characteristically associated with the feeling of "despair" including the aforementioned "nausea".
This is brought on by the realization that no matter how long one parties and drinks and cavorts, or in the second case, no matter how many books are studied and lectures attended, the secrets to life and a happy existence are simply not to be found in this fashion. This leads to a despair darker than night, a wanting to make something of oneself, to be remembered or to be depended upon. This sense of duty brings on the second stage of existential appropriation, the religious stage.
Though termed the "religious stage", this stage is embodied by a clear desire to do a duty to something bigger than oneself. The activities that result in this stage are usually ones of great responsibility, sometimes with others depending upon the individual. Examples of such activities include marriage, volunteering in a military organization, or becoming religiously devout or joining the monastic order. During this religious stage, feelings of guilt are eventually encountered because no matter how devout, responsible, or courageous people can be, certain things occur that are out of their control and they inevitably fail themselves in some way by not being able to uphold their responsibility or oath. For example, an individual could be the best soldier he can be, but alas, his comrade is felled by a bullet that he could not stop, and is thus guilt stricken.
Finally the individual undergoes a schism in which a discovery is made that one can really only be true to oneself, and that from this idiom stems the powerful realization of free will and the terrible responsibility that comes with it. This final stage of realization is known as the existential or enlightened stage. In this stage an individual is aware that his or her "reason for being" is solely decided by his or her own decisions, and nothing else. This enlightenment is the mantle of true freedom, even onto the decision of suicide!
Paris - Sartre 
Then in Paris, after the Second World War, many literary and philosophical ideas changed. Albert Camus wrote The Outsider, The Fall and The Plague.
Jean-Paul Sartre, who had studied under Martin Heidegger, started a magazine called Les Temps Modernes with Maurice Merleau-Ponty. Sartre's main philosophical book is Being and Nothingness (L'Être et le Néant), while Existentialism is a Humanism (L'existentialisme est un humanisme) is a concise and less technical work suitable for the beginner. He also wrote plays, such as No Exit (Huis Clos), and novels, such as Nausea (La nausée) and the The Roads to Freedom (Les chemins de la liberté) trilogy.
When discussing Sartre in the line of existentialists it may be useful to note that he was by far the most political of the lot. Sartre became a Marxist and in some sense lost some repectability among many existentialists — because he had begun to rely on an external set of values rather than an authentic set of choices.