Jean Baudrillard's death did not take place. "Dying is pointless," he once wrote. "You have to know how to disappear." The New Yorker reported a reading the French sociologist gave in a New York gallery in 2005. A man from the audience, with the recent death of Jacques Derrida in mind, mentioned obituaries and asked Baudrillard: "What would you like to be said about you? In other words, who are you?" Baudrillard replied: "What I am, I don't know. I am the simulacrum of myself."

Baudrillard, whose simulacrum departed at the age of 77, attracted widespread notoriety for predicting that the first Gulf war, of 1991, would not take place. During the war, he said it was not really taking place. After its conclusion, he announced, imperturbably, that it had not taken place. This prompted some to characterise him as yet another continental philosopher who revelled in a disreputable contempt for truth and reality.

Yet Baudrillard was pointing out that the war was conducted as a media spectacle. Rehearsed as a wargame or simulation, it was then enacted for the viewing public as a simulation: as a news event, with its paraphernalia of embedded journalists and missile's-eye-view video cameras, it was a videogame. The real violence was thoroughly overwritten by electronic narrative: by simulation.

Such had been Baudrillard's name for the defining problem of the age since the 1970s, when he wrote that the Marxian problem of class struggle had been replaced, in the "post-industrial" era, with the problem of simulation. He thus anticipated, by a decade or two, later arguments about the nature of "virtual reality". Pop culture paid tribute to Baudrillard's prescience in Andy and Larry Wachowski's 1999 film The Matrix, about a near-future Earth where human society is a simulation designed by malign machines to keep us enslaved. Hacker hero Neo (Keanu Reeves) hides his contraband software in a hollowed-out copy of one of the philosopher's books, and rebel chief Morpheus (Laurence Fishburne) quotes Baudrillard's most famous formula: "Welcome to the desert of the real."

Baudrillard was invited to collaborate on the sequels, but declined. He later protested wryly that The Matrix had got him wrong: "The most embarrassing part of the film is that the new problem posed by simulation is confused with its classical, Platonic treatment ... The Matrix is surely the kind of film about the matrix that the matrix would have been able to produce."

Baudrillard was born in the cathedral town of Reims in north-eastern France. His grandparents were peasants and his parents became civil servants. He was the first of his family to go to university, studying German at the Sorbonne in Paris, and he later said that this led to a break with his family and cultural milieu. In 1956 he began teaching German at a French lycée, and in the early 1960s published essays on literature for the journal Les Temps Modernes, as well as translating works of Bertolt Brecht and Peter Weiss.

In 1966, Baudrillard joined the University of Nanterre, a small, fiercely radical institution that was to become notable as the incubator of the Mouvement du 22 Mars and its subsequent role in the évènements of May 1968. (Baudrillard later said he "participated" in the student revolts.) That same year, his first book, The System of Objects, was published. With the sociologist Henri Lefebvre and the cultural critic Roland Barthes as his intellectual mentors, he gave sharp, ironic readings of interior-design materials, gadgets, washing powder and other everyday phenomena.

In subsequent works, including The Consumer Society (1970), The Mirror of Production (1973), and Forget Foucault (1977), Baudrillard developed arguments about the increasing power of the "object" over the "subject" in modern society, and the way in which protest and resistance were increasingly absorbed and turned into fuel by the symbolic "system" of capitalism. During this period, he also wrote on art and architecture for the journal Utopie.

The 1981 volume Simulacra and Simulation (the book that later appeared in The Matrix) gained a wide audience, and Baudrillard soon found himself a globetrotting academic superstar, discoursing on his themes of "seduction" (the term that escapes the binary opposition of "production" and "destruction") and "hyper-reality" (the simulated realm that is "more real than the real"). In 1986 he moved from Nanterre, which had, he lamented, become "normalised", to the university of Paris-IX Dauphine.

Baudrillard characterised the 1990s, with its wishful illusions about the "end of history", as a "stagnant" period in which events were on strike. Eventually the strike was broken by the attacks on the US of September 11 2001. Baudrillard called it "the ultimate event, the mother of all events".

"It is the terrorist model," he wrote, "to bring about an excess of reality, and have the system collapse beneath that excess."

Subsequently, for Baudrillard, there was no longer any need for the media to virtualise events, as in the first Gulf war, since the war's participants had thoroughly internalised the rules of simulation. His 2004 essay, War Porn, observed how the photographs from Abu Ghraib enacted scenes of fetishistic pornography, concluding: "It is really America that has electrocuted itself."

Baudrillard took to calling his works "theory fictions": because the present is always more fantastical than the most lurid science fiction, "theory" must compete with it on an imaginative level. So Baudrillard offered himself as an extrapolator, a canary in the cultural coalmine. "My work is paradoxical," he explained. "It's surrealist like fiction." He found a sympathetic soul in the novelist JG Ballard, who called him "the most important French thinker of the last 20 years". (In 1974, Baudrillard had hailed Ballard's Crash as "the first great novel of the universe of simulation".)

Baudrillard once wore a gold lamé suit with mirrored lapels while reading his poetry in a Las Vegas bar. If he didn't take himself particularly seriously, his critics complained that he didn't take anything else seriously either. A recurring charge was that it was politically and morally irresponsible, at the very least, to speak of the "unreality" of modern war, because to do so was to ignore the realities of killing and suffering. Baudrillard's response, in his 2004 book The Lucidity Pact, or The Intelligence of Evil, was laconic: "The reality-fundamentalists equip themselves with a form of magical thinking that confuses message and messenger: if you speak of the simulacrum, then you are a simulator; if you speak of the virtuality of war, then you are in league with it and have no regard for the hundreds of thousands of dead ... it is not we, the messengers of the simulacrum, who have plunged things into this discredit, it is the system itself that has fomented this uncertainty that affects everything today."

One sceptical British interviewer called Baudrillard a "philosopher clown", a description to which he probably would not have objected, instead taking it as an invitation to think about the social function of clowns. As he once argued: "It is the task of radical thought, since the world is given to us in unintelligibility, to make it more unintelligible, more enigmatic, more fabulous." He was an aphorist. "Contemporary art is contemporary only with itself," he growled; or: "Our sentimentality towards animals is a sure sign of the disdain in which we hold them."

Baudrillard, who is survived by his wife Marine, had once written a playful account of his personal evolution, from "pataphysician" (a scientist of imaginary solutions) at 20, to "viral" at 60. When I saw him in 2000, he was 70 years old. What was he now? He chuckled. "Well, let's see, at 70, I would say that I am ... transfini. Beyond the end. It was my fateful strategy to go beyond the concept, so as to see what happens beyond." Now, perhaps, he knows.

· Jean Baudrillard, philosopher and sociologist, born July 29 1929; died March 6 2007