I've never seen anything by Gavin Turk that was worth looking at. This show is no exception. I liked it. What I mean is that he raises the issue of looking and thinking: he's a good artist not because the objects he makes are aesthetically marvellous, but because of the ideas they provoke. They are about value, society, art, the artist and power - who has it and who doesn't.
For his degree show at the Royal College of Art in 1991, Turk exhibited a blue plaque on the wall of his space, which read "Borough of Kensington Gavin Turk Sculptor Worked Here 1989-1991". There was nothing else in the room. The title, Cave, referred to Plato's parable of ideal forms: the watchers at the back of the cave believe that mere shadows cast on the wall by flickering flames constitute "reality". He didn't get his degree.
This was the beginning of Turk's self-obsession. What kind of self is it? It's the self of the artist, but not his own self. It's quite different to the self of Tracey Emin. Emin is a romantic who wants to be adored. She wants her self to be noticed, heard, appreciated, marvelled at - not just her celebrity self but her inner self of pain. She makes a big show of tortured authenticity, whereas Turk is obviously false.
Throughout a critically and commercially successful career, which started almost as soon as he failed his sculpture degree, he has made a point of disguising or theatricalising himself. He has exhibited waxworks of himself as Che Guevara dead on a slab, Marat dead in his bath and (at the same time, both icons merged into a single Turk) Sid Vicious and Andy Warhol. He also mocked up a Hello! cover of himself with his wife and their new baby.
How do we value art if it's not merely a matter of success or celebrity or the market? In the early 1960s, Jasper Johns cast a pair of beer cans in bronze, painted them and exhibited them. His inspiration was an insult he overheard in a bar. The abstract expressionist Willem de Kooning complained about Leo Castelli, his own dealer, who also showed Johns: "That son of a bitch! He could sell two beer cans as a work of art!" Something is valued - the real. Something is despised - the false. Johns painted the cans loosely and energetically. It was obvious to the naked eye that they were painted, but not that they were bronze. This was a Duchampian gag about perception, but un-Duchampian in that at least one part of the gag was positively aesthetic: Johns had done something soulless and mechanical - mere casting - but then painted the cast in an animated style, that is, apparently soulfully.
Johns is the great artist of enig-ma. Duchamp is the great artist of nihilism. For artists of Turk's generation the great Duchamp icon is his urinal-as-art, entitled Fountain, of 1917. An object - something formerly banal and despised - becomes art merely because an artist says so. A few years later, in Why Not Sneeze Rose Selavy?, Duchamp cast sugar cubes out of marble. From art materials and ancient craft techniques, he made something that appeared to be mass-produced. Later, in the 1950s, Johns created his own brand of ironic-aesthetic painting: irony had been a weapon against aestheticism for Du-champ, but Johns made them compatible.
Fifty years later, with Turk's show at White Cube, the question of what is the valued object and what is the shadow is recast in terms of society's rejects: the homeless. In person, Turk, born in Guildford in 1967, seems almost classless. Does he care about the homeless? I think he does. Does it matter? Maybe not - if it did you'd be talking about an art that wasn't emotionally or politically disengaged, as this clearly is. There'd be something offensive about appropriating homelessness as an element in an intellectual puzzle.
Turk has looked in the direction of the disaffected before. He exhibited a waxwork of a tramp, with himself as the model. And he's done rubbish bags before, too. The ones here are grouped in a huddle. The whole show is a single installation called The Golden Thread.
Because it includes a labyrinth, you're encouraged to think of the symbolism of the Minotaur: a shocking revelation, maybe something terrible or murderous, after a journey in the dark.
The rubbish bags are all black. One has a yellow drawstring. Noticing this, you might remember the orange of the dosser's grimy sleeping bag you passed downstairs in the gallery foyer. For an instant, the sleeping bag seemed to go naturally with the slightly scruffy floor. But then you look around and realise that it doesn't go at all with the corporate gallery environment. And, of course, it's not a real bag but a carefully painted bronze cast. The rubbish bags are bronze, too.
In a recent interview in the Independent, Tim Marlow, director of exhibitions at White Cube, revealed that the price of the eight rubbish bags - which make up a single work called Pile - is £75,000. He said the meaning is a joke to do with people's perception of modern art as "rubbish". Here, that perception is being turned on its head, because although Pile is literally rubbish (in Marlow's words), it is "amazingly intricately made" and full of "skill". Supposedly directed against philistinism, this is itself a philistine idea of art - something that looks very, very like something else. What about it having some life of its own?
But then Turk's objects never do have that, exactly. They are very literal. The transcending element is his ideas. It's a kind of joke art. Not even kind of. As Marlow says, it is a joke. But can that be enough? Who knows? Shouldn't we be getting somewhere by now?
Now you see the labyrinth. It stands on its own, the size of a room, in a large space. It resembles 1960s minimal art - metal and glass, very precisely cut and assembled. You might bother to enter, but supposing you then felt claustrophobic - why subject yourself to an unpleasant experience when you can perfectly well imagine from out here what it's like inside? You see your own reflection in the glass. It's clear you're being reflected back to yourself. Maybe this is the Minotaur!
The contemporary art world is sometimes amusing, but often hateful and repulsive. Self-effacement in favour of looking, even if it's in rather a light-hearted way, at tough-minded issues - the public's relationship to art and the idea of "the artist" - is refreshing.
Gavin Turk's The Golden Thread is at White Cube, Hoxton Square, London N1 (020 7930 5373) until 28 February
Matthew Collings's most recent book is Matt's Old Masters: Titian, Rubens, Velazquez, Hogarth (Weidenfeld & Nicolson)