It was not just that Sartre popularized the term "existentialism" -- a term, like "natural" applied to food, meant little but suggested a entire universe of positive qualities: depth, seriousness, engagement, freedom and above all the courage to look unpalatable truths in the face.
Sartre was regarded as a creative as well as an intellectual giant. He was not only a philosopher (his major work, "Being and Nothingness," was published in 1943) but also a notable novelist ("Nausea," "The Age of Reason") and playwright ("No Exit").
Sartre also epitomized the public's idea of an adversary intellectual.
The product of a bourgeois upbringing, he was adamantly anti-bourgeois; the beneficiary of Western education and freedoms, he was stridently anti-Western, especially anti-American.
When his he was awarded the Nobel Prize for literature in 1964 (largely for his autobiography, "The Words," which may be his best book), Sartre characteristically refused the honor.
Sartre never met a Left-wing idea he didn't embrace.
He was not only pro-Soviet, he was pro-Mao, pro-Castro, pro-Third World, even pro-terrorism.
In 1954, he declared: "There is a total freedom of criticism in the USSR." He later wrote a glowing preface for Frantz Fanon's "The Wretched of the Earth" -- a book that the historian Paul Johnson called "the most influential of all terrorist handbooks."
"I believe in illegality," Sartre wrote in La Cause du Peuple, a self-described "revolutionary, proletarian, Communist paper." In 1973, he even admitted his deep interest in the Baader-Meinhof Group: "a real revolutionary group," he said, though one that had "started a little too soon."
The real key to Sartre's character is his intellectualizing aestheticism, his tendency to dissolve reality in a play of abstract philosophical or political categories.
It is in this sense that we must understand his admission that he tended to regard words as "the quintessence of things."
"The truth is," Sartre wrote, " "I treat my feelings as ideas: with an idea, one pushes it till it cracks -- or finally becomes 'what it really was.'"
For Sartre, life was essentially an agenda for reflection. No feeling, no sensitivity, no impression was left unencumbered by interpretation; no interpretation was left undisciplined by further scrutiny.
Sartre's tremendous appetite for abstraction and his suspicion of the life of feeling is particularly evident in his uncompromising, absolutist approach to the cardinal existentialist virtues of authenticity and freedom.
In "Being and Nothingness," for example, Sartre defines freedom as a spontaneous "upsurge" that is "beyond causes, motives, ends."
Sartre's discussion of freedom is elusive to say the least.
It is worth noting that without "causes, motives, or ends," the idea of freedom must remain empty.
For if it is to be more than mere accident or spontaneity, if it is not to be arbitrary, then freedom must be limited by particular choices that are based on intelligible criteria -- criteria that are in some sense given, not (as Sartre would have it) "freely produced."
In default of such criteria, freedom can be little more than an invigorating slogan.
(Compare Raymond Aron's description of "the dullness of real emancipation" in "The Opium of the Intellectuals:" how much more pedestrian it sounds, but how much more substantial it turns out to be!)
Sartre claims to value freedom above all else; but freedom for him is more man's fate and burden than choice; ineradicable, freedom is yet too absolute to be fully grasped or realized; hence one is not so much privileged as "condemned to be free."
It is the same with Sartre's notion of authenticity.
Anything like a definition of authenticity is hard to come by in Sartre's work.
Yet it is clear that he understood authenticity to be characterized chiefly by the individual's defiant assertion of unqualified freedom in the face of an essentially absurd reality.
Since unqualified freedom entails unqualified responsibility, authenticity meant being "totally responsible for one's life."
"In short," he wrote, "I was seeking the absolute, I wanted to be an absolute, and that's what I called morality."
The problem is that the absolute, by nature completely abstract, is too empty to serve as a criterion for morals or a cue for authenticity.
But as a rhetorical trope, allegiance to the absolute can exert a powerful appeal.
Sartre's understanding of authenticity, tinged as it was with Romantic longing, exploits that appeal to the hilt: "In relation to Gauguin, Van Gogh and Rimbaud," he noted, "I have a distinct inferiority complex because they managed to destroy themselves ... I am more and more convinced that, in order to achieve authenticity, something has to snap."
It follows that, in Sartre's view, authenticity flourishes best in extreme situations. In the early 1940s, Sartre remarked: "it's much easier to live decently and authentically in wartime than in peacetime."
It is true that, plunged into crisis, men and women often experience moments of moral clarity that are rare in everyday life. And they sometimes respond to such situations with uncommon selflessness and valor.
But does this mean that it is easier to live "decently and authentically" during war than in peacetime?
On the contrary, hasn't wartime generally been the occasion of profound moral degradation and anarchy?
The notion that it is somehow easier to live "authentically" in wartime than in the "bourgeois" stability of peace will suggest itself seriously only to someone who discounts the importance of ordinary social life in forming our ideas of authenticity, someone for whom "the authentic" is paradigmatically a lonely battle of an aloof and isolated self.
Just how aloof and isolated Sartre conceived the self to be is exemplified in his contention "the first value and first object of will is: to be its own foundation."
Or, as he put it in "Being and Nothingness," "the best way to conceive the fundamental project of human reality is to say that man is the being whose project is to be God."
This is not to suggest that Sartre believed that God exists.
On the contrary, he remarked in his notebooks that he had been an atheist since the age of 12.
Nevertheless, according to Sartre, the idea of God, though self-contradictory, functions as the ineluctable (if usually unacknowledged) ideal to which we all aspire.
Mankind, he wrote, is "perpetually haunted by a totality ... without being able to be it."
The thought that man's "fundamental project" is to be his own foundation -- that is, to be God -- stands at the center of Sartre's philosophy.
This is also to say that Sartre's philosophy is saturated with pride, with hubris.
Pride, as St. Augustine put it, is at bottom "a perverse kind of exaltation" in which one seeks to "abandon the basis on which the mind should be firmly fixed" and seeks instead to become self-created.
It is pride, for example, that underlies the famous conclusion to "Being and Nothingness," in which Sartre contends that "man is a useless passion" -- "useless" because his every action is haunted by a desire that for a mortal, finite creature is essentially self-contradictory: the desire to be completely sovereign, autonomous, self-sufficient, the desire to be God.
Sartre's understanding of man's "fundamental project" also has profound implications for his view of relations with other people.
If one desires to be God, then the very existence of others will be felt as a threatening infringement on one's sovereignty.
Because man's pride demands complete self-sufficiency, relations with other people are from the beginning cast into the essentially antagonistic mold of power relations.
It follows that, as Sartre wrote in "Being and Nothingness," "conflict is the original meaning of being-for-others."
As Garcin exclaimed near the end of "No Exit:" "Hell is other people."
Not without reason is this oft-quoted line so widely identified with the Sartrean philosophy.
Sartre's existentialist rhetoric bristles with condemnations of "reification" and treating people as objects -- as "means" rather than "ends."
But his writings everywhere reveal that both his temperament and his underlying view of man incline him to do just that.
"Nothing is dearer to me than the freedom of those I love," Sartre writes in a passage about seduction, "but the fact is this freedom is dear to me provided I don't respect it at all. It's a question not of suppressing it, but of actually violating it."
Without the erotic charge that allows for seduction, Sartre finds that he is basically uninterested in people.
Friendship "bores" him, and his relations with men tend to be tenuous and superficial. "I think I have no need of friends because, basically, I don't need anybody ... I prefer to derive everything from myself."
No doubt Jean-Paul Sartre was one of the most gifted writers of his generation; he was also one of its greatest monsters.
(Roger Kimball is managing editor of The New Criterion)