The dirtiest show in town

Nothing succeeds like excess and the rude and gross have always had their place in art. But are we really getting the joke?

Gross! A great spotty, hairy arse fills the frame, nothing hidden, and with a bunch of thistles perilously stuffed into its lowered pants - all rendered with that attention to physical detail that one expects from Flemish painting of the 16th century. The image is obviously meant as a rude joke; it's joined to another, less offensive, picture of a man pulling a rather disgusting face. But how rude is it meant to be? Is it merely jolly? Is it really filthy? Is it positively, socially dangerous? The humour and rudeness of other cultures is hard to judge.

Gross! A great spotty, hairy arse fills the frame, nothing hidden, and with a bunch of thistles perilously stuffed into its lowered pants - all rendered with that attention to physical detail that one expects from Flemish painting of the 16th century. The image is obviously meant as a rude joke; it's joined to another, less offensive, picture of a man pulling a rather disgusting face. But how rude is it meant to be? Is it merely jolly? Is it really filthy? Is it positively, socially dangerous? The humour and rudeness of other cultures is hard to judge.

Mooning and gurneying are prominent incidents in a new touring show called Carnivalesque, which has just opened at three venues in Brighton. That anonymous diptych is one of its star-turns. But in this anthology of images, dating from the Middle Ages to the present day, you'll find all sorts of festive vulgarity. There are fools and crazies, masks and grotesques, monstrous creatures, unruly crowds, over-eating, overt vomiting and defecating, and other generally rollicking carryings-on associated with carnival, the traditional pre-Lent public blow-out that flourished in Europe up to the 19th century, and still continues in some places.

The exhibition itself is an example of what you might call academic trickle-down. So often, ideas that began in literary or philosophical enquiry find their way, years later, into the visual arts. The Carnivalesque offers a story of more than usual delay. Back in the 1920s, the Soviet critic Mikhail Bahktin coined this notion when studying Rabelais. It didn't surface in Western criticism until the 1960s, and then had a pretty good run, but any literary critic peddling carnivals now would seem thoroughly out of date. Time for the art show, then.

And as with many themed art shows, you may wonder whether the theme really works or, if it doesn't, whether that matters. Certainly artists have directly depicted carnival activity, some of the best among them Breughel, Jacques Callot, Tiepolo, Goya, James Ensor - and they're all represented here. But Bahktin's idea extends beyond the literal feast to encompass almost any sort of anarchic, bottoms-up tendency, the rebellion of low against high, popular against élite, body against soul. I'm not sure quite how this show decided what to include. But anything with bottoms in seems to gain automatic entry.

A themed show should be judged not on its consistency but on the quality of the individual finds the theme makes possible. And Carnivalesque finds very well. Bottoms, for instance, turn up inRowlandson's delightful drawing of people tumbling down a spiral staircase, all feet in the air and rears exposed, and also a deeply perverse 16th-century woodcut, A Human Sundial, with a supine man being entered at both ends by metal rods and an enormous turd in the foreground. I suspect this image is somehow less bizarre than it seems, and a bit more explanatory caption would have helped. But it's not always easy to distinguish a forgotten symbolic scheme - the images here of fools being hatched from eggs, say - from the exuberantly irrational.

What's nice about the show is that the modern viewer's understanding is always being put on the spot. Do we catch the tone? Do we have the least idea what's going on? Probably the most remarkable exhibits are a collection of small Dutch lead badges, late-medieval, whose catalogue titles give you the general idea: Vagina walking on stilts crowned with three phalluses; Three phalluses carrying a crowned vagina; Phallus roasting on spit, vagina as dripping pan. These were badges worn by pilgrims, or perhaps parodies of them, or something. Basically, no one has a clue.

By contrast, in the prints on the popular theme, The World Turned Upside Down, everything is clear. In strips of scenes, the natural and social orders are neatly reversed. Horses ride men, pigs slaughter them, rabbits hunt them, fish fish for them, children beat their parents, women fight duels, men nurse babies, people walk on their hands, buildings float in the clouds and the sun and moon lie grounded and bewildered. The charming thing is how diagrammatic the anarchy is. These prints only strengthen a sense of orderliness - they just show how the world goes, and just how it would be if it went the other way.

There are only a few works here that convey, in themselves, a real sense of disorder. The drawings of the Regency cartoonist James Gilray do seem truly deranged - and I suppose that something like that is an important component of carnival. It's not just rude, euphoric and "celebratory": it's rather frightening. The general loss of control feels sinister, spooky, sabbatical. So it has to be participatory, and not a spectacle with an audience.

In a way that goes for carnivalesque art as a whole. There can't be any such thing. But it makes a particular problem for the contemporary section of this show. True, there has been much "transgressive" body-based art lately. Carnivalesque includes some examples, such as a video of some gross and violent cookery by Paul McCarthy. But the thing about artistic trangression is that it involves a very sharp distinction between the performer and the audience - between the shocker and the shockee. It couldn't be further from carnival spirit.

So does the show tell us anything today? When Bahktin's idea of the carnivalesque was rediscovered in the 1960s, the timing then was plain: the carnival as orgy-cum-uprising, a happy combination of sexual and political liberation. But nowadays it is normal now to say that carnivals were not really subversive. On the contrary, they were safety valves, permitted naughtiness, designed to dissipate and neutralise disruptive energies.

But looking at it like that assumes that we have only two choices: either total rebellion or total obedience. It is to believe that a society must always be of one mind. The point about carnivals is that they're a public recognition that feelings are mixed, that the opposite is also true, that if things are to be held sacred there will be blasphemy as well. This point is largely lost on us.

Think of the recent May Day disorders. The statue of Churchill was insulted. The Cenotaph was desecrated. An outrage? But what could be more obvious than to want to abuse such repositories of public value? Of course, these particular acts were too freelance, too irregular, to count as carnival behaviour. But it's quite possible to imagine a public festival in which the abusive and ludicrous adornment of national monuments was a fixture.

The effect would be to bring these pieces of street lumber alive. And the turf mohican that was appended to Churchill's head is exemplary. Surely, when he saw it, even the editor of the Daily Mail felt a small smile caressing his lips. It was rude - but not exactly inappropriate to a warrior-hero. Long before punk, mohicans were worn by US troops during the invasion of Europe. (In fact, it was more appropriate than anyone, eco-anarchist or leader-writer, seems to have appreciated: Churchill himself had requested no statue, but rather a garden to be planted in his memory.)

So don't say carnival is over. The energies and the skills are there. They just need to be properly organised.

Carnivalesque: Brighton Museum and Art Gallery, Church Street, to 2 July (closed Wed); Fabrica Church, Ship Street, to 2 July (closed Wed); University of Brighton Gallery, to 10 June, everyday. Admission to all free. Tours to Nottingham (July- Sept) and Edinburgh (Oct-Dec)