Robert Hughes on updating The Shock of the New

Twenty-five years is a mere eyeblink in the story of Egyptian, Mayan or even medieval English art, but it is a long time in the modern or (weasel word) post-modern context, and if one is given a single programme - a mere 55 minutes - to bring the story up to date from where The Shock of the New left off when we finished making the series, one is bound to fail. Too much has happened in art. Not all of that "too much", admittedly, is compelling or even interesting, but the ground is choked with events that defy brief, coherent summary. So we decided to sample rather than summarise. Most of the "1980s artists" over whom such a fuss was made have turned out to be merely rhetorical, or inept, or otherwise fallen by the wayside. Is there anyone who really cares much what Julian Schnabel or David Salle, for instance, are now doing? Do the recent paintings of Sandro Chia or Georg Baselitz excite interest? Maybe in your breast, but not in mine.

The period has been full of conceptual art, but conceptual art makes for utterly droning TV. On the other hand, there are a few - a very few - artists of the "neo-expressionist" generation whose work continues its efforts to take on the burden of history, to struggle to explain our bizarre and terrible times to us in memorable visual terms, and one of the most complex and rewarding of these talents, uneven though he can be, is surely Anselm Kiefer. No less so is Paula Rego, a painter I'd hardly heard of until a few years ago because she was scarcely known in the US - but how strongly put together, how viscerally and deeply felt, are her renderings of bad parental authority and of the psychic nightmares that lie just be low the supposedly sweet surface of childhood! Rego is a great subversive without a trace of the dull, academic conceptualism that renders the more approved American radical-feminists of the 80s-90s so tedious - and she draws superbly, which her sisters across the Atlantic have either forgotten or never learned to do. Like Kiefer, but unlike most painters at work today, she does art with a strong political content that never turns into a merely ideological utterance.

It used to be that media-based, photo-derived art looked almost automatically "interesting". It cut to the chase instantly, it mimicked the media-glutted state of general consciousness, it was democratic - sort of. The high priest of this situation was of course the hugely influential Andy Warhol, paragon of fast art. I am sure that though his influence probably will last (if only because it renders artmaking easier for the kiddies) his paragonhood won't, and despite the millions now paid for his Lizzes and Elvises, he will shrink to relative insignificance, a historical figure whose resonance is used up. There will be a renewed interest - not for everyone, of course, but for those who actually know and care about the issues - in slow art: art that takes time to develop on the retina and in the mind, that sees instant communication as the empty fraud it is, that relates strongly to its own traditions.

It doesn't matter whether the work is figurative or not. Sean Scully's big abstracts retain much more than a memory of experienced architecture, but they relate to the human body too, and there is something wonderfully invigorating about the measured density with which their paint brings them into the world. Not everything of value is self-evident and there is no reason in the world why art should be. Nor is it true that instantaneous media, such as photography and video, should or can deliver "more" truth than drawing. All you can say is that they offer a different sort of truth. This is an issue with which an artist like David Hockney has been struggling for years, and it's fascinating to see how he has given up on the photographic collages he used to make in favour of pure recording in watercolour, of which he is such a master.

Styles come and go, movements briefly coalesce (or fail to, more likely), but there has been one huge and dominant reality overshadowing Anglo-Euro-American art in the past 25 years, and The Shock of the New came out too early to take account of its full effects. This is the growing and tyrannous power of the market itself, which has its ups and downs but has so hugely distorted nearly everyone's relationship with aesthetics. That's why we decided to put Jeff Koons in the new programme: not because his work is beautiful or means anything much, but because it is such an extreme and self-satisfied manifestation of the sanctimony that attaches to big bucks. Koons really does think he's Michelangelo and is not shy to say so. The significant thing is that there are collectors, especially in America, who believe it. He has the slimy assurance, the gross patter about transcendence through art, of a blow-dried Baptist selling swamp acres in Florida. And the result is that you can't imagine America's singularly depraved culture without him. He fits into Bush's America the way Warhol fitted into Reagan's. There may be worse things waiting in the wings (never forget that morose observation of Milton's on the topo-graphy of Hell: "And in the lowest depth, a lower depth") but for the moment they aren't apparent, which isn't to say that they won't crawl, glistening like Paris Hilton's lip-gloss, out of some gallery next month. Koons is the perfect product of an art system in which the market controls nearly everything, including much of what gets said about art.

An interesting result of the growing power of the market is that artists and their dealers are looking for ways, through copyright law, to con trol what is written or broadcast about the work, so as to prevent critics who might feel less than prostrate admiration for it from saying anything about it at all. On TV, if you can't show, you can't tell. I have seen quite a lot of this in recent years; it is here to stay, and getting worse. Sometimes the results look merely silly, as when the American conceptual artist Mel Bochner, whose work (consisting of vaguely related words printed in capitals on canvas in various tasteful colours) we filmed in the last Whitney Biennial in New York, waited until a few days before broadcast to announce, through his agent, that he "did not wish to participate" in our film. Never mind.

Damien Hirst was another story. We were in London, hoping to film some of Hirst's work and perhaps a brief interview with him for The New Shock of the New. Oh no, absolutely not, came the word back. "Damien," said his gallery, "is very fragile to criticism." Could this fragile aesthete re ally be the Hemingwoid sheep-slicer, dot-painter and all-round bad boy? I had not actually written about Hirst's work (though I consider him a much more real artist than some of the lesser geniuses of our time) but it was clear he suspected he might be treated as someone less than Michelangelo or, for that matter, Richard Serra. The last message from him was that never, no-how, under no circumstances, could we film anything of his in the current show at the Tate, In a Gadda da Vida. Why? "Conservation reasons," it said. Better to discourage anything being said about the great work than risk the utterance of dissent or doubt.

I think the drift of such examples (and there are plenty of others) is clear enough. The art world is now so swollen with currency and the vanity of inflated reputation that it is taking on some of the less creditable aspects of showbiz. Hollywood doesn't want critics, it wants PR folk and profile-writers. Showbiz controls journalism by controlling access. The art world hopes to do the same, though on a more piddly level. No other domain of culture would try this one on. No publisher, fearing that an unfavourable review, would attempt to stop a book critic quoting from some novel. No producer would make a guarantee of innocuousness the price of a critic's ticket to the theatre. It just wouldn't happen. But in art, it can. And since it can, as Bill Clinton remarked in another context, it does.

· The New Shock of the New is on BBC2, Saturday, 9.05pm.