The media are interested in anything that shocks. So we've been primed by Saatchi's hype to be amazed that Stella Vine, one of the artists in his "New Blood" exhibition, used to be a stripper, and that one of her paintings is of a heroin addict and another is of a supposedly "frightened" Lady Di. Actually, neither of these paintings has any visual interest, they're just ideas. The ideas are vapid. No one in the media or among the aspirational middle-class audience, or even among the bigwigs of the art world, is all that clear about the value or non-value of the stupid in art, or the shallow or the pretentious. Like Saatchi himself, none of them is moved by art's profundity. Instead, they want to know how art plays: are you joining in some kind of group if you go along with pretending to be interested in it? Or are you missing out in some way?
The majority of the artists on show here are new trendies. A list of their works with explanations sets the tone - the tacky printout immediately conveys Saat-chi's contempt for his audience. Insulting illiteracy (haywire possessives and plurals), empty claims couched in teenage fan magazine style and random jargon combine to make meaningless doggerel: "Mesmerising in its simplistic complexity, Shawcross's sculpture offers a certain mysticism through making . . ."
This description refers to a machine that produces multicoloured rope. Works by other new artists include more rope, this time made of toilet paper, and a hat made of little aeroplanes. There's also a form- less lump of massed items of furniture. Looking at some sculptures resembling strings of play-dough spaghetti, only white instead of kiddie-coloured, you ask yourself: why do we put up with this? Why don't we fight back?
A few of the featured artists are old trendies. Their works here are good by the artists' own standards, with the exception of Mark Quinn's latex human skin, which doesn't have anything to offer beyond literalness - a problem shared by his controversial sculpture of a pregnant disabled woman for the fourth plinth in Trafalgar Square. Chris Ofili's use of elephant shit, on the other hand, is pretty silly, but it's not the main thing his paintings offer; most important is the richness of the layered space that Ofili creates. Rudeness is still there: it's definitely a lump of shit on a canvas. But even as you're looking, the physical thing and the conceptual gesture of including it are transcended. This is what art in the modernist tradition tends to be good at: it makes crudeness and marvellous refinement seem to coexist magically.
For the purpose of this show, it would be enough for Ofili to be simply crude. The art has only to be "out there" and "funky", like Liz Neal's Spunk Chandelier, which the list of works eulogises: "Luxurious and filthy to the core, Neal dreams up a Regency House Party of her own - one far more intriguing than Channel 4's - but definitely too naughty to be aired!"
Other works in the show are by artists of the same generation as Ofili and Quinn who either never achieved fame or achieved it only recently. Dexter Dalwood's fantasy evocations of exotic pop-culture locations such as Michael Jackson's home and Laboratoire Garnier are redeemed from fatuousness by the artist's ability to make wobbly-edged planes of transparent colour seem special in some way. The problem with Grayson Perry (who shot to world fame last December when he wore a dress to receive the Turner Prize) is exactly the lack of anything worth looking at in the work, in contrast with the abundance of uplifting things in the Perry life story - his good nature, individualism and intelligence. These are marvellous but irrelevant. We're supposed to be impressed that "craft" has come into art, but Perry's pots look like they were made in a factory. And we're supposed to find the drawings on them "disturbing", but they've been the standard fare of art careerism for years: swearing, violence and angry references to the art world.
Richard Wilson, Paula Rego, Luc Tuymans and Martin Kippenberger make up a further sub-group. The first two are establishment pets but off the trendy circuit - Wilson is good, Rego overrated. The second two are international stars. Tuymans copies photos. The combination of his handling of paint, which could be described as mannered nervousness, and a generalised parchment non-colour is irresistible to collectors and reviewers. They interpret obvious daftness (the look the thing has of having taken ten minutes to do) as amazing restraint and profundity. These qualities are not ones we associate with Saatchi, but then we know he doesn't buy anything for its intrinsic quality but for the publicity and selling-on potential.
Tuymans's dourness is a calculated tease - the allure of the plain. The plainness of Kippenberger's painting of the interior of Berlin's Paris Bar is the result of it having been executed by an assistant, someone who paints backdrops for a living. Other Kippenbergers here were actually executed by him and show his liveliness. The bar is where Kippenberger and his friends used to hang out in the late 1970s. Its arty reputation continued into the 1990s, and lives on to this day. None of this has anything to say to Saatchi's audience, nor to Saatchi, who wants to set up Kippenberger (who died in 1997) as an influential figure for his trendy discoveries. But the arrivistes are opportunistic pom-poms while Kippenberger was a heavyweight, a revolutionary whose punky-ness and humour were set off by a humane, old-fashioned romanticism.
"New Blood" is really Saatchi testing out the new zeitgeist, which can be defined as a repetition of more or less freak-show sights. He demonstrates it will work commercially and poses the question of "What is it?" at the same time. I think we should complain about his crassness, but I don't say he isn't clever.
"New Blood" is at the Saatchi Gallery, County Hall, London SE1 (020 7928 8195) until 4 July
Matthew Collings's most recent book is Matt's Old Masters (Weidenfeld & Nicolson)