The science police

Physicists Alan Sokal and Jean Bricmont, critics of postmodernism, talk to Harriet Swain

Two men are sitting at a cafe table in the mathematics department of Imperial College, London, quoting French philosophers at each other and shrieking with laughter. "And then there's the bit when Kristeva says ...", chuckles one. "And what about Deleuze's comment that ...", chortles the other. "And Lacan!", they say together, dissolving into giggles.

The men are Alan Sokal, author of Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity, a hoax article parodying postmodernist beliefs, (particularly postmodernists' use of scientific language) and his accomplice Jean Bricmont. Sokal, 43, professor of physics at New York University, is a slight, twitchy figure with the pallor of a man who spends too much time thinking, away from natural light. Bricmont, 46, professor of theoretical physics at the University of Louvain, Belgium, is larger and ruddier. His knapsack is stuffed with papers and books, including, oddly, Cultural Studies for Beginners, which he continually rustles and shuffles seeking references to prove points.

When Sokal is speaking Bricmont fidgets and, at one point, yawns extraordinarily loudly. But he clearly thinks Sokal is brilliant. "He works very very fast," he confides, as Sokal protests, modestly. And later, "he speaks very good French, really very good". They have known each other for more than 20 years - Bricmont was on Sokal's thesis panel - and it shows. They contradict and interrupt and talk over each other like an old married couple or a comedy double act.

So how does this odd duo come to be playing London's trendiest intellectual venues, packing out the Institut Francais and the London School of Economics, not only with eminent philosophers and physicists, but also with glamorous young students of sociology, literary critics and political theorists?

In 1996, Sokal's article was published in the cultural studies journal Social Text by editors who had no idea it was a hoax. Soon afterwards he revealed the joke, explaining in another journal that most of the article was nonsense and taken seriously merely because it sounded good. The fact that it was published at face value showed, he argued, the absurd work that passed for serious scholarship in cultural studies and other university humanities departments.

Newspapers throughout the world picked up the story and Sokal had to field calls from television and radio stations, as well as deal with hundreds of letters. His web-site (www.physics.nyu.edu/faculty/sokal.html) is still the centre of lively debate.

The article was followed up with a book, Intellectual Impostures, co-written with Bricmont, this time picking out psychoanalysts, literary critics, philosophers and sociologists and showing up parts of their writing as meaningless babble. It was published in France last year, comes out in England this month and receives its American debut in the autumn.

So much for the facts. Their value has turned out to be much more far-reaching. Sokal's parody has been taken as an attack not just on intellectual dishonesty but on intellectuals per se, on French intellectuals in particular, on left-wing politics and on the humanities by the sciences.

Sokal and Bricmont, however, are swift to deny it is any such thing. "It is not a group combat of any kind," says Sokal. "It's an intellectual debate. The lines do not go along nationalities or disciplines."

Rejecting praise from rightwingers, who have interpreted the article as an argument against political correctness, Sokal speaks at length about his left-wing credentials - he taught mathematics at the National University of Nicaragua - and says his anxiety to expose sloppiness by left-wing scholars was sparked in part by the desire to protect left-wing ideas. To the charge of being anti-French, he says "For us ideas have no nationality." Accused of attacking the humanities, he says they are supporting serious work in these fields by publicly exposing charlatanism.

The aim of their book, he argues, is far more precise and limited. It tries to do two things. First to attack social scientists who use concepts and terminology from mathematics and science without apparently knowing what they mean and end up writing nonsense. Sokal and Bricmont accuse such people of possibly exploiting the prestige of the natural sciences to give their own discourse "a veneer of vigour". "Our goal," they say, "is precisely to say the king is naked" or, more prosaically, "to reveal bull****". Second, they want to analyse "certain confusions of thought" frequent in postmodernist writings that bear on the content or philosophy of natural sciences. The principal "confusion of thought" they identify is epistemic relativism, which claims the truth or falsity of a factual statement is relative to an individual or social group (see box below).

Sokal is strikingly fluent in speaking and writing but "mathematical physics is my first love". Unlike Bricmont, whose upbringing was much more literary, Sokal wanted to study science from the age of five. The son of an electrical engineer and a biologist, he was brought up just outside Boston. He dabbled with philosophy as an undergraduate at Harvard but says he was never interested in it professionally. His work, which he says he wants to resume as soon as the fuss over Intellectual Impostures dies down, concentrates on the border between elementary particle physics and the physics of phase transitions, which, he explains as "what happens when you boil a kettle".

His dispute with certain writings in the humanities came from his day-to-day political reading. It was given life by a book written by Paul Gross and Norman Levitt that dealt with many of the issues raised by Intellectual Impostures. "I earn my living as a physicist but there are other things in life that interest me," he says. "I'm interested in physics because I want to know things about the nature of the universe. I'm interested in philosophy for the same reason."

Higher Superstition: the Academic Left and its Quarrels with Science, the Gross and Levitt book, took him to the library where he soon gathered a thick dossier of examples of "nonsense" writings. Rather than writing a standard piece criticising them, he "had the impish idea that maybe it would be more fun to write an article praising them". It was to be simultaneously "a parody, an annotated bibliography of nonsense, a hoax and an experiment". But it was "a totally uncontrolled experiment", he adds quickly.

Asked if it was perhaps a cruel way of going about things, Bricmont instantly shows a flash of conscience. He does sometimes feel sorry for the authors they are ridiculing but "they got a lot of mileage out of it," he says. Some are still receiving academic prizes for their erudition. Sokal is less sympathetic. "If you write bull**** you have to accept that someone will expose it. Some of our comments are almost schoolmarmish in their prudence." "Some people say we lack a sense of humour ..." begins Bricmont. "Which is true," Sokal adds quickly. "We left lots of it out of the book because we thought it would be too cruel."

But over the past few days the twosome have had several chances to exercise their wit in a long line of public engagements. At the London School of Economics last week they met one of the subjects of their ridicule - Bruno Latour, sociologist of science at the Ecole Nationale Superieure des Mines, Paris. In the chapter of Intellectual Impostures devoted to Latour, the authors accuse him of lack of precision in his style, "fatally flawed" analysis and "fundamental misunderstandings about the theory of relativity".

On stage at the LSE the debate turned into a comedy show. While Sokal spoke from the platform, hurling at Latour examples of muddled thinking, nonsensical sentences, absurd statements, Bricmont heckled from the floor in his support.

The urbane Latour, armed with a set of props in the shape of intricate diagrams of his thinking, and a sense of timing to rival Paul Merton's, gently swatted Sokal's criticisms away with a Gallic shrug or a nod of agreement. It rapidly became clear that the two were arguing not only from different positions but from entirely different worlds.

The debate at the LSE ended with a victory for Sokal in terms of content but a triumph for Latour on style. This was not the first time the two had met following Sokal's book-length attack. On their first encounter, Latour presented Sokal with a bottle of wine - from his family's own vintage.

WHAT IS POST-MODERNISM ANYWAY?

Physicist Alan Sokal's objection is to the "subjectivist" thinking pursued by postmodernists, that denies the existence of objective reality or downplays its practical relevance in favour of an emphasis on who is assessing that reality and how. Sokal argues that there is a real world out there, that its properties are not social constructions, and that facts and evidence do matter. He says that if all is discourse and "text" then knowledge of the real world is superfluous, and physics nothing more than another branch of cultural studies.

Anyone who believes that the laws of gravityare mere social conventions, he says,is invited to try transgressing those conventions from the windows of his flat on the 21st floor.

Sokal's opponents say he has oversimplified the definition of postmodernism, that the divide between facts and the way we think about those facts is not as stark as he implies and that the relationship between "scientific method" and the kinds of truths scientists discover cannot be ignored.

As philosopher Bruno Latour explains, a group of scientists in a room with all the available evidence about dinosaurs laid out before them - skeletons, footprints etc - may come to a conclusion about what a dinosaur is. But when they come out of the room to tell people of their conclusions, how certain can anyone be that dinosaurs actually existed?

WHAT THEY SAID IN LAST WEEK'S LONDON DEBATES

* Physicist Alan Sokal: "No culture can change the laws of physics whatever they are. We can have accurate or inaccurate views about the world of physics. But the world of physics is what it is, whether we believe in it or not."

* Literary critic Didier Eribon: "Sokal and Bricmont aren't entitled as physicists to sayto scholars on which topics it is legitimate to reflect and on which topics it isn't".

* Sokal: "We have no desire to prevent anyone from speaking about anything. The intellectual value of an intervention is determined by its content, not by the identity of the speaker, much less by his or her diplomas".