Jean - Paul Sartre was born in Paris as the only child of Jean - Baptiste Sartre, an officer of the French Navy, and Anne - Marie Schweitzer. His mother was of Alsatian origin and the first cousin of Nobel Prize laureate Albert Schweitzer. (Her father, Charles Schweitzer, was the older brother of Albert Schweitzer's father, Louis Théophile.) When Sartre was 15 months old, his father died of a fever. Anne - Marie moved back to her parents' house in Meudon, where Sartre was raised with help from her father, a professor of German, who taught Sartre mathematics and introduced him to classical literature at a very early age. At twelve his mother remarried and the family moved to La Rochelle, where he was frequently bullied.

As a teenager in the 1920s, Sartre became attracted to philosophy upon reading Henri Bergson's essay Time and Free Will: An Essay on the Immediate Data of Consciousness. He studied and earned a doctorate in philosophy in Paris at the École Normale Supérieure, an institution of higher education that was the alma mater for several prominent French thinkers and intellectuals. It was at ENS that Sartre began his life long, sometimes fractious, friendship with Raymond Aron. Sartre was influenced by many aspects of Western philosophy, absorbing ideas from Kant, Hegel, Kierkegaard, Husserl and Heidegger, among others.

From his first years in the École Normale, Sartre was one of its fiercest pranksters; In 1927, his antimilitarist satirical cartoon in the revue of the school, coauthored with Georges Canguilhem, forced the director Gustave Lanson to resign. In the same year, with his comrades Niza, Larroutis, Baillou and Herland, he organized a media prank following Charles Lindbergh's successful New York - Paris flight; Sartre & Co. called newspapers and informed them that Lindbergh was going to be awarded an honorary École degree. Many newspapers, including Le Petit Parisien, announced the event on 25 May. Thousands, including journalists and curious spectators, showed up, unaware that what they were witnessing was a stunt involving a Lindbergh look - alike. The public's resultant outcry forced Lanson to resign again. In 1939, in his famous short story collection The Wall, referring to a fake turd, he will say that in pranks "There is more destructive power than in all the works of Lenin."

In 1929 at the École Normale, he met Simone de Beauvoir, who studied at the Sorbonne and later went on to become a noted philosopher, writer and feminist. The two became inseparable and lifelong companions, initiating a romantic relationship, though they were not monogamous. Sartre served as a conscript in the French Army from 1929 to 1931 and he later argued in 1959 that each French person was responsible for the collective crimes during the Algerian War of Independence.

Together, Sartre and de Beauvoir challenged the cultural and social assumptions and expectations of their upbringings, which they considered bourgeois, in both lifestyle and thought. The conflict between oppressive, spiritually destructive conformity (mauvaise foi, literally, "bad faith") and an "authentic" way of "being" became the dominant theme of Sartre's early work, a theme embodied in his principal philosophical work L'Être et le Néant (Being and Nothingness) (1943). Sartre's introduction to his philosophy is his work Existentialism is a Humanism (1946), originally presented as a lecture.

In 1939 Sartre was drafted into the French army, where he served as a meteorologist. He was captured by German troops in 1940 in Padoux, and he spent nine months as a prisoner of war — in Nancy and finally in Stalag 12D, Trier, where he wrote his first theatrical piece, Barionà, fils du tonnerre, a drama concerning Christmas. It was during this period of confinement that Sartre read Heidegger's Sein und Zeit (Being and Time), later to become a major influence on his own essay on phenomenological ontology. Because of poor health (he claimed that his poor eyesight and exotropia affected his balance) Sartre was released in April 1941. Given civilian status, he recovered his teaching position at Lycée Pasteur near Paris, settled at the Hotel Mistral near Montparnasse in Paris, and was given a new position at Lycée Condorcet, replacing a Jewish teacher who had been forbidden to teach by Vichy law.

After coming back to Paris in May 1941, he participated in the founding of the underground group Socialisme et Liberté with other writers Simone de Beauvoir, Merleau - Ponty, Jean - Toussaint Desanti and his wife Dominique Desanti, Jean Kanapa, and École Normale students. In August, Sartre and Beauvoir went to the French Riviera seeking the support of André Gide and André Malraux. However, both Gide and Malraux were undecided, and this may have been the cause of Sartre's disappointment and discouragement. Socialisme et liberté soon dissolved and Sartre decided to write, instead of being involved in active resistance. He then wrote Being and Nothingness, The Flies, and No Exit, none of which were censored by the Germans, and also contributed to both legal and illegal literary magazines.

After August 1944 and the Liberation of Paris, he wrote Anti - Semite and Jew. In the book he tries to explain the etiology of "hate" by analyzing antisemitic hate. Sartre was a very active contributor to Combat, a newspaper created during the clandestine period by Albert Camus, a philosopher and author who held similar beliefs. Sartre and Beauvoir remained friends with Camus until 1951, after the publication of Camus' The Rebel. Later, while Sartre was labeled by some authors as a resistant, the French philosopher and resistant Vladimir Jankelevitch criticized Sartre's lack of political commitment during the German occupation, and interpreted his further struggles for liberty as an attempt to redeem himself. According to Camus, Sartre was a writer who resisted, not a resistor who wrote.

After the war ended Sartre established Les Temps Modernes (Modern Times), a quarterly literary and political review, and started writing full time as well as continuing his political activism. He would draw on his war experiences for his great trilogy of novels, Les Chemins de la Liberté (The Roads to Freedom) (1945 – 1949).

The first period of Sartre's career, defined in large part by Being and Nothingness (1943), gave way to a second period as a politically engaged activist and intellectual. His 1948 work Les Mains Sales (Dirty Hands) in particular explored the problem of being both an intellectual at the same time as becoming "engaged" politically. He embraced Marxism (but did not join the Communist Party) and took a prominent role in the struggle against French rule in Algeria. He became perhaps the most eminent supporter of the FLN in the Algerian War and was one of the signatories of the Manifeste des 121. Furthermore, he had an Algerian mistress, Arlette Elkaïm, who became his adopted daughter in 1965. He opposed the Vietnam War and, along with Bertrand Russell and others, organized a tribunal intended to expose U.S. war crimes, which became known as the Russell Tribunal in 1967.

His major defining work after 1955, the Critique de la raison dialectique (Critique of Dialectical Reason) appeared in 1960 (a second volume appeared posthumously). In Critique, Sartre set out to give Marxism a more vigorous intellectual defense than it had received up until then; he ended by concluding that Marx's notion of "class" as an objective entity was fallacious. Sartre's emphasis on the humanist values in the early works of Marx led to a dispute with a leading leftist intellectual in France in the 1960s, Louis Althusser, who claimed that the ideas of the young Marx were decisively superseded by the "scientific" system of the later Marx.

Sartre went to Cuba in the '60s to meet Fidel Castro and spoke with Ernesto "Che" Guevara. After Guevara's death, Sartre would declare him to be "not only an intellectual but also the most complete human being of our age" and the "era's most perfect man." Sartre would also compliment Che Guevara by professing that "he lived his words, spoke his own actions and his story and the story of the world ran parallel."

During a collective hunger strike in 1974, Sartre visited Red Army Faction leader Andreas Baader in Stammheim Prison and criticized the harsh conditions of imprisonment.

Towards the end of his life, Sartre explicitly embraced anarchism.

In 1964, Sartre renounced literature in a witty and sardonic account of the first ten years of his life, Les mots (Words). The book is an ironic counter blast to Marcel Proust, whose reputation had unexpectedly eclipsed that of André Gide (who had provided the model of littérature engagée for Sartre's generation). Literature, Sartre concluded, functioned ultimately as a bourgeois substitute for real commitment in the world.
In October 1964, Sartre was awarded the Nobel Prize in Literature but he declined it. He was the first Nobel Laureate to voluntarily decline the prize, and he had previously refused the Légion d'honneur, in 1945. The prize was announced on 22 October 1964; on 14 October, Sartre had written a letter to the Nobel Institute, asking to be removed from the list of nominees, and that he would not accept the prize if awarded, but the letter went unread; on 23 October, Le Figaro published a statement by Sartre explaining his refusal. He said he did not wish to be "transformed" by such an award, and did not want to take sides in an East vs. West cultural struggle by accepting an award from a prominent Western cultural institution. After the prize award he tried to escape the media by hiding in the house of Simone's sister Hélène de Beauvoir in Goxwiller in Alsace.

Though his name was then a household word (as was "existentialism" during the tumultuous 1960s), Sartre remained a simple man with few possessions, actively committed to causes until the end of his life, such as the student revolution strikes in Paris during the summer of 1968 during which he was arrested for civil disobedience. President Charles de Gaulle intervened and pardoned him, commenting that "you don't arrest Voltaire."

In 1975, when asked how he would like to be remembered, Sartre replied:

I would like [people] to remember Nausea, [my plays] No Exit and The Devil and the Good Lord, and then my two philosophical works, more particularly the second one, Critique of Dialectical Reason. Then my essay on Genet, Saint Genet.... If these are remembered, that would be quite an achievement, and I don't ask for more. As a man, if a certain Jean - Paul Sartre is remembered, I would like people to remember the milieu or historical situation in which I lived,... how I lived in it, in terms of all the aspirations which I tried to gather up within myself.

Sartre's physical condition deteriorated, partially because of the merciless pace of work (and using drugs for this reason, i.e., amphetamine) he put himself through during the writing of the Critique and a massive analytical biography of Gustave Flaubert (The Family Idiot), both of which remained unfinished. Sartre became almost completely blind in 1973. Jean - Paul Sartre was also a notorious chain smoker that could have contributed to his health deterioration.

He died 15 April 1980 in Paris from edema of the lung.

Sartre lies buried in Cimetière de Montparnasse in Paris. His funeral was well attended, with estimates of the number of mourners along the two hour march ranging from 15,000 to over 50,000.

The basis of Sartre's existentialism can be found in The Transcendence of the Ego in which he says that the thing - in - itself is infinite and overflowing. Sartre refers to any direct consciousness of the thing - in - itself as a "pre - reflective consciousness." Any attempt to describe, understand, historicize etc. the thing - in - itself, Sartre calls "reflective consciousness." There is no way for the reflective consciousness to subsume the pre - reflective, and so reflection is fated to a form of anxiety, i.e., the human condition. The reflective consciousness in all its forms, (scientific, artistic or otherwise) can only limit the thing - in - itself by virtue of its attempt to understand or describe it. It follows, therefore, that any attempt at self knowledge (self consciousness — a reflective consciousness of an overflowing infinite) is a construct that fails no matter how often it is attempted. Consciousness is consciousness of itself insofar as it is consciousness of a transcendent object.

The same holds true about knowledge of the "Other". The "Other" (meaning simply beings or objects that are not the self) is a construct of reflective consciousness. A volitional entity must be careful to understand this more as a form of warning than as an ontological statement. However, there is an implication of solipsism here that Sartre considers fundamental to any coherent description of the human condition. Sartre overcomes this solipsism by a kind of ritual. Self consciousness needs "the Other" to prove (display) its own existence. It has a "masochistic desire" to be limited, i.e., limited by the reflective consciousness of another subject. This is expressed metaphorically in the famous line of dialogue from No Exit, "Hell is other people."

Sartre stated that "In order to make myself recognized by the Other, I must risk my own life. To risk one's life, in fact, is to reveal oneself as not - bound to the objective form or to any determined existence — as not - bound to life", meaning the value of the Other's recognition of me depends on the value of my recognition of the Other. In this sense to the extent that the Other apprehends me as bound to a body and immersed in life, I am myself only an Other as Ego.

The main idea of Jean - Paul Sartre is that we are, as humans, "condemned to be free." This theory relies upon his belief that there is no creator, and is formed using the example of the paper knife. Sartre says that if one considered a paper knife, one would assume that the creator would have had a plan for it: an essence. Sartre said that human beings have no essence before their existence because there is no Creator. Thus: "existence precedes essence". This forms the basis for his assertion that since one cannot explain their own actions and behavior by referencing any specific human nature, they are necessarily fully responsible for those actions. "We are left alone, without excuse".

Sartre maintained that the concepts of authenticity and individuality have to be earned but not learned. We need to experience death consciousness so as to wake up ourselves as to what is really important; the authentic in our lives which is life experience, not knowledge.

As a junior lecturer at the Lycée du Havre in 1938, Sartre wrote the novel La Nausée (Nausea) which serves in some ways as a manifesto of existentialism and remains one of his most famous books. Taking a page from the German phenomenological movement, he believed that our ideas are the product of experiences of real life situations, and that novels and plays can well describe such fundamental experiences, having equal value to discursive essays for the elaboration of philosophical theories such as existentialism. With such purpose, this novel concerns a dejected researcher (Roquentin) in a town similar to Le Havre who becomes starkly conscious of the fact that inanimate objects and situations remain absolutely indifferent to his existence. As such, they show themselves to be resistant to whatever significance human consciousness might perceive in them.

This indifference of "things in themselves" (closely linked with the later notion of "being - in - itself" in his Being and Nothingness) has the effect of highlighting all the more the freedom Roquentin has to perceive and act in the world; everywhere he looks, he finds situations imbued with meanings which bear the stamp of his existence. Hence the "nausea" referred to in the title of the book; all that he encounters in his everyday life is suffused with a pervasive, even horrible, taste — specifically, his freedom. The book takes the term from Friedrich Nietzsche's Thus Spoke Zarathustra, where it is used in the context of the often nauseating quality of existence. No matter how much Roquentin longs for something else or something different, he cannot get away from this harrowing evidence of his engagement with the world. The novel also acts as a terrifying realization of some of Kant's fundamental ideas; Sartre uses the idea of the autonomy of the will (that morality is derived from our ability to choose in reality; the ability to choose being derived from human freedom; embodied in the famous saying "Condemned to be free") as a way to show the world's indifference to the individual. The freedom that Kant exposed is here a strong burden, for the freedom to act towards objects is ultimately useless, and the practical application of Kant's ideas proves to be bitterly rejected.

Sartre's views were counterposed to those of Albert Camus in the popular imagination. In 1948, the Roman Catholic Church placed his complete works on the Index of prohibited books. Most of his plays are richly symbolic and serve as a means of conveying his philosophy. The best known, Huis - clos (No Exit), contains the famous line "L'enfer, c'est les autres," usually translated as "Hell is other people."

Aside from the impact of Nausea, Sartre's major contribution to literature was The Roads to Freedom trilogy which charts the progression of how World War II affected Sartre's ideas. In this way, Roads to Freedom presents a less theoretical and more practical approach to existentialism.

While the broad focus of Sartre's life revolved around the notion of human freedom, he began a sustained intellectual participation in more public matters in 1945. Prior to this — before the Second World War — he was content with the role of an apolitical liberal intellectual: "Now teaching at a lycée in Laon [...] Sartre made his headquarters the Dome café at the crossing of Montparnasse and Raspail boulevards. He attended plays, read novels, and dined [with] women. He wrote. And he was published" (Gerassi 1989: 134). Sartre and his lifelong companion, Simone de Beauvoir, existed, in her words, where "the world about us was a mere backdrop against which our private lives were played out" (de Beauvoir 1958: 339).

Sartre portrayed his own pre - war situation in the character Mathieu, chief protagonist in The Age of Reason, which was completed during Sartre's first year as a soldier in the Second World War. By forging Mathieu as an absolute rationalist, analyzing every situation, and functioning entirely on reason, he removed any strands of authentic content from his character and as a result, Mathieu could "recognize no allegiance except to [him]self" (Sartre 1942: 13), though he realized that without "responsibility for my own existence, it would seem utterly absurd to go on existing" (Sartre 1942: 14). Mathieu's commitment was only to himself, never to the outside world. Mathieu was restrained from action each time because he had no reasons for acting. Sartre then, for these reasons, was not compelled to participate in the Spanish Civil War, and it took the invasion of his own country to motivate him into action and to provide a crystallization of these ideas. It was the war that gave him a purpose beyond himself, and the atrocities of the war can be seen as the turning point in his public stance.

The war opened Sartre's eyes to a political reality he had not yet understood until forced into continual engagement with it: "the world itself destroyed Sartre's illusions about isolated self determining individuals and made clear his own personal stake in the events of the time". Returning to Paris in 1941 he formed the "Socialisme et Liberté" resistance group. In 1943, after the group disbanded, Sartre joined a writers' Resistance group, in which he remained an active participant until the end of the war. He continued to write ferociously, and it was due to this "crucial experience of war and captivity that Sartre began to try to build up a positive moral system and to express it through literature".

The symbolic initiation of this new phase in Sartre’s work is packaged in the introduction he wrote for a new journal, Les Temps Modernes, in October 1945. Here he aligned the journal, and thus himself, with the Left and called for writers to express their political commitment. Yet, this alignment was indefinite, directed more to the concept of the Left than a specific party of the Left.

Sartre's philosophy lent itself to his being a public intellectual. He envisaged culture as a very fluid concept; neither pre - determined, nor definitely finished; instead, in true existential fashion, "culture was always conceived as a process of continual invention and re-invention". This marks Sartre, the intellectual, as a pragmatist, willing to move and shift stance along with events. He did not dogmatically follow a cause other than the belief in human freedom, preferring to retain a pacifist's objectivity. It is this over - arching theme of freedom that means his work "subverts the bases for distinctions among the disciplines". Therefore, he was able to hold knowledge across a vast array of subjects: "the international world order, the political and economic organization of contemporary society, especially France, the institutional and legal frameworks that regulate the lives of ordinary citizens, the educational system, the media networks that control and disseminate information. Sartre systematically refused to keep quiet about what he saw as inequalities and injustices in the world".

Sartre always sympathized with the left, and supported the French Communist Party (PCF) until the 1956 Soviet invasion of Hungary. Following the Liberation the PCF were infuriated by Sartre's philosophy, which appeared to lure young French men and women away from the ideology of communism and into Sartre’s own existentialism. From 1956 onwards Sartre rejected the claims of the PCF to represent the French working classes, objecting to its authoritarian tendencies. In the late 1960s Sartre supported the radical left, then known as "Maoists," a movement that rejected the authority of established communist parties. However, despite aligning with the "Maoists," Sartre said after the May events: "If one rereads all my books, one will realize that I have not changed profoundly, and that I have always remained an anarchist." He would later explicitly allow himself to be called an anarchist.

In the aftermath of a war that had for the first time properly engaged Sartre in political matters, he set forth a body of work which "reflected on virtually every important theme of his early thought and began to explore alternative solutions to the problems posed there". The greatest difficulties that he and all public intellectuals of the time faced were the increasing technological aspects of the world that were outdating the printed word as a form of expression. In Sartre's opinion, the "traditional bourgeois literary forms remain innately superior", but there is "a recognition that the new technological 'mass media' forms must be embraced" if Sartre's ethical and political goals as an authentic, committed intellectual are to be achieved: the demystification of bourgeois political practices and the raising of the consciousness, both political and cultural, of the working class. The struggle for Sartre was against the monopolizing moguls who were beginning to take over the media and destroy the role of the intellectual. His attempts to reach a public were mediated by these powers, and it was often these powers he had to campaign against. He was skilled enough, however, to circumvent some of these issues by his interactive approach to the various forms of media, advertising his radio interviews in a newspaper column for example, and vice versa.

The role of a public intellectual can lead to the individual placing himself in danger as he engages with disputed topics. In Sartre's case, this was witnessed in June 1961, when a plastic bomb exploded in the entrance of his apartment building. His public support of Algerian self determination at the time had led Sartre to become a target of the campaign of terror that mounted as the colonists' position deteriorated. A similar occurrence took place the next year and he had begun to receive threatening letters from Oran.