Don't have a vache: From Barthes to Bart

Meet Barthes (pron. bart), the dead French philosopher. Now meet Bart (pron. bart), the immortal cartoon character. How are they related? Alors, let us count the ways, dude, says Stephen Bayley (pron. bay-lee)

Had he not been run over by a laundry truck on a Paris street in 1980, Roland Barthes would today be writing about Saddam's moustache, Beckham's crosses, Rollerblades and The Simpsons. Or any other signs that give meaning to our world. Barthes was France's most successful intellectual, and his interests included literature, history, theatre, painting, advertising, design, photography and Moroccan boys. These, north African youth apart, are all collected in a new exhibition at the Centre Pompidou in the city he made his own.

Given the way he helped shape our view of the world, the exhibition is entirely justified. Barthes interrogated the everyday world, moving from formal literary criticism to writing brilliantly on steak and chips, Arcimboldo and the Tour de France. It is a happy accident of homophonics that the most endearing champions of popular culture, in theory and practice, are each pronounced Bart – the professor would have enjoyed consanguinity with The Simpsons. Equally, it is haunting evidence of his legacy that the precise details of the fatal laundry truck still beg to be explained. Barthes had certainly written perceptively on detergents ("dirt is no longer stripped from the surface, but expelled from its most secret cells"). Surely the camion de la blanchisserie must signify something? Was the offending vehicle a Unic a Saviem or a Berliet? Barthes would have wanted to know.

We have no one quite like Roland Barthes: our idea of an intellectual is someone more resembling Jeremy Paxman than this suave Parisian boulevardier. Obsessed with thinking about thinking, Barthes' life was a stylish intellectual adventure. He was also a hedonist, a meticulous dresser, gay, sensitive, sardonic, sociable, gossipy. He made reading a sacrament. A lonely, tubercular youth became a Professor of Pleasure. For Barthes, dealing with a text was an erotic transaction: reading was "jouissance", a word which means both joy and "coming" in the sexual sense. To experience this enjoyable sense of escape, Barthes argued, you need to get in deeper.

But these same texts which engaged him sensually were also "signs". And signs became Roland Barthes' business. He began writing in 1947 in Albert Camus' little magazine Combat, essays subsequently published in 1953 as Le Degré Zéro de l'écriture. "Degré Zéro" may be translated as "bottom line". This quest for the essence preoccupied Barthes. When later he wrote about "Etat Zéro" he meant neutrality and to Barthes there could never be such a thing. In the modern world everything has meaning and it is the critic's job to chase down that fugitive essence and explain it to the public.

Barthes, who was born in Cherbourg in 1915, effortlessly crossed barriers between the daunting Collège de France and St Germain's more welcoming Café Flore, still in the brainy and bookish afterglow of its Sartre-de Beauvoir period. But Jean-Paul Sartre and Barthes could not have been more different – one a priapic old goat, the other an elegant eagle-nosed, ebony-eyed Antinous. Indeed, the example of Barthes confirms every jealous English prejudice about the French: he managed to be intellectually fastidious and immensely popular. Never, as Nietzsche said, trust a god who can't dance.

The French intellectual tradition made this revolution in perception possible. In the Twenties the historians Marc Bloch and Lucien Febvre decided that real history should not concern battles and the politicians, but should be concerned with large patterns of behaviour ("la longue durée") and with the passions and beliefs of individuals ("mentalités"). This led to various histories of private life and studies of the mundane; of these Barthes became a consummate master.

Structuralism, a French term for "interdisciplinary", is an approach to the world that combines the methodologies of litcrit, anthropology, linguistics and Freud. And the most important aspect of structuralism is semiotics, the study of signs, a specialism Barthes made his own. Edmund Leach explained semiotics when he wrote:

"Any human creative act starts as a mental operation which is then projected on to the external world ... The mental operations of any human designer are circumscribed not only by the qualities of his material and his objectives, but by the design of the human brain itself."

Barthes turned this forbidding stuff into something rather fine, what Susan Sontag called the taxonomy of jubilation. And nowhere was Barthes' jubilation shown better than in Mythologies, his affectionate satire of bourgeois taste. The 1957 publication of this selection of sly ruminations turned him into a public figure. In London we had kitchen sink drama; in Paris they had kitchen sink analysis. The most significant essay in Mythologies was about a car. The introduction of the radical new Citroën DS19 at the Paris Salon de l'Automobile in 1955 had caused a significant media flurry. So keen was Citroën to demonstrate the sensational sculpture of this astonishing vehicle that it was originally shown on a pylon, without wheels lest the rude intrusion of tyres compromise the public's pure aesthetic response to its divine shape. In French "DS" sounds like the word for "goddess" and this happy accident put Barthes into a mood of mock piety. No one has ever explained the significance of industrial design better than Barthes in this bravura opening sentence:

"I think that cars today are almost the exact equivalent of the great Gothic cathedrals: I mean the supreme creation of an era, conceived with passion by unknown artists, and consumed in image if not in usage by a whole population which appropriates them as a purely magical object."

Here we have the essential elements of Barthes' approach to his material. There is a sensuality in the writing, but there is also something contrarian. Like Flaubert, Barthes detested "l'opinion courante". He said current opinion – which he called Doxa, he was a classicist – was like Medusa: if you acknowledged it, you became petrified. So, instead, with the "puissance de subversion" he set about debunking it. But he was not hostile: his instincts were celebratory, not combative.

Through Barthes, the structuralist view of the world has passed effortlessly into the mainstream of modern thought, so much so that it is difficult to appreciate now the freshness of his insights. Meanwhile, in the closed world of French universities, after the laundry-truck incident, new intellectual fashions began to strut the academic catwalk. The appealing subtleties of structuralism were replaced by the ponderous absurdities of deconstruction. Barthes' successors have included a lot of morally and intellectually bankrupt poseurs, viciously exposed in Alan Sokal's and Jean Bricmont's sensational Impostures Intellectuelles of 1997.

But there are inconsistencies in Barthes. As one who set out to clarify the world, he ended up obfuscating it. For instance, writing of voile and muslin in his 1967 book The Fashion System: "Formally, the assertion of species is simply a binary opposition of the type a/(A-a); strictly speaking therefore, the genus is not a paradigm of various species, but only the grouping which limits the substantial possibilities of opposition."

Selective quotation does Barthes no favours. His best books are the suggestive essays, not the theoretical postulates. He was a master of generalisation. (Later he admitted he wrote The Fashion System only for money.)

Barthes enjoyed his success and was a supreme egotist. His friend Susan Sontag said his interest in you was really just your interest in him. He even published a review of his autobiography, titled "Barthes on Barthes on Barthes". This dizzying self-reference defines the same popular culture that Barthes made respectable. Yet in his last book, the posthumous journal Incidents, he betrays a touching vulnerability. The book portrays a listless, melancholy figure. He describes wanting a glass of champagne at odd times of day while wandering Paris's streets. He dwells on his fear, and acceptance of, sexual rejection. With time to kill, he is anxious that a cup of coffee may not last more than 15 minutes. There is nothing to read in today's Le Monde. He fancies a Laotian boy he sees in a bar, but goes home instead to read Dante through a daze of migraine. One day in September 1979, he writes: "I am paralyzed by the boredom of having to attend the opening of Pinter's No Man's Land."

Was Roland Barthes a bit of a fraud or one of the most original thinkers of the 20th century? It plays both ways. His semiotic analysis of a glass of red wine included finger-wagging digressions into Third World debt and why the Algerians would be better off with cash crops other than vines. Meanwhile, he ordered soft-boiled eggs, sausages and Bordeaux at Café Flore. He admitted early in his career, "What I claim is to live to the full the contradictions of my time, which may well make sarcasm the condition of truth."

Yet there was astonishing intellectual consistency. Twenty years after Mythologies, Barthes gave his inaugural lecture at the Collège de France. There he was, saying the same thing, but not repeating himself. In the same year he wrote Fragments d'un Discours Amoureux which became a best-seller.

He may have created a unique form of modern criticism, but he was intensely old-fashioned himself, harbouring a profund nostalgia for a lost age of literacy and art. The exhibition at the Centre Pompidou shows the polite conservatism of his enthusiasms: a late painting by Mondrian, industrial design by Eliot Noyes, images of priapically engorged Sicilian youth by the Edwardian homo-erotic photographer Wilhelm von Gloeden, sketches by the surrealist André Masson and a portrait of Barthes himself by the eroticist Pierre Klossowski.

Re-read Barthes now and you realise that there was no great methodology, no "great theory". Rather, he makes his point through cumulative aphorism and shrewd observation. His achievement? To make us take The Simpsons seriously. As Professor Morris Zapp says in David Lodge's academic satire Small World, "I'm a bit of a deconstructionist myself."

Thanks to Roland Barthes we all are. With his unique vision, Barthes has helped us to read the world. "Tout comprendre est tout pardonner," as they say down the Flore.

Roland Barthes: 27 November to 10 March, Centre Pompidou, Paris. Gallery 2, level 6, every day except Tuesday (00 33 1 44 78 14 63).