We haven't heard much from Charles Saatchi for... it must be several weeks now. Well, he is back with a purpose. He has a fancy new gallery in Chelsea opening soon that needs a successful launch so you'll be hearing from him frequently in the coming months.

The Times reported yesterday that he has bought almost the entire degree shows of three postgraduate students at the Royal Academy Schools. This latest example of his “wrap 'em up, I'll take the lot” approach to artistic discernment tells us a great deal about him and the warped modus operandi of a contemporary art market where reputations are conjured out of nothing. Most significantly, it tells us that Mr Saatchi is not, as he is so often dubbed, an art collector but an art dealer. Collectors do not buy in bulk, store in bulk, show in bulk and sell in bulk.

This mass acquisitiveness is not the instinct of an art lover. Collectors select discriminatingly. Dealers, on the other hand, are, at root, shopkeepers and buy with sale in mind. All recent evidence points to Mr Saatchi being an upmarket shopkeeper. Yes, he has given a few works to the Tate and handed over scores to the Arts Council and impoverished regional museums, but none of these gifts is of the first rank and, in some cases, the generosity was dubious for including duds he'd been unable to sell at auction.

Virtually everything he has famously bought and sensationally exhibited was later sold at a huge profit. It was reported recently that, of the 100 works exhibited in the Sensation exhibition at the Royal Academy and its subsequent promotional world tour, he still owns only a handful.

It is fair to assume that the three graduates he picked up cheaply this week will be subjected to the same tried-and-tested formula of “brand development”. To put these purchases in perspective, a few weeks ago he sold at auction for £637,000 a painting by Cecily Brown that he bought two years earlier for £30,000. Booked against this, 25 works by unknowns for a total of £40,000 is pocket money, well worth the gamble. He will need only one of the three to succeed even slightly to cash in. Doubtless all will soon resurface in his Chelsea gallery surrounded by the premium publicity that only a prize-winning adman can orchestrate.

It will probably work. Over the past 20 years Mr Saatchi has achieved the Midas touch envied by other art dealers. Simply by buying work he could induce the credulous rich to dash out and buy up other pieces by the same artist, thereby raising prices. Uniquely, he can drive the market. It is a game that he clearly relishes playing.

This raises the $64,000 question: did the artist have to be good in the first place to merit the Saatchi treatment? At this point Mr Saatchi's genius enters the equation. Almost before anyone, he realised that the importance of an art object need have nothing to do with the perceivable quality of its appearance. If Marcel Duchamp could turn a urinal into art, he could turn Gary Hume, a dauber who is now Professor of Painting at the Royal Academy no less, into a world-renowned artist. He deserves a medal for that one alone.

Many outsiders bewildered by the art scene may reasonably assume that some criteria underpin such judgments. This couldn't be farther from the truth. Not a single thread of connoisseurship exists in the work beloved of the Arts Council and the Tate galleries. If Sir Nicholas Serota, the director of the Tate, declares his delight in spending £4 million on “one of the greatest sculptures of the 20th century” we have to believe in his judgment, even if the welded scrap metal so proudly unveiled resembles nothing so much as the rusting chassis of a delivery van.

Who are we to argue with the most important arbiter of contemporary art? Likewise, if Sir Nicholas tells us that a room full of boulders is a profound statement about mortality, many will believe him, fearful of being thought reactionary, or just plain stupid. It is our perception of Sir Nicholas's unquestionable authority that convinces us of these objects' worth.

What we are rarely told with convincing argument is why only this pile of boulders is about mortality and not any other piles that we happen to encounter.

This limitless flexibility in making judgments lies at the heart of Charles Saatchi's success. He knows, and the art market knows, that what a work looks like has ceased to matter. It is the managed perception of its status that matters. As an adman, Mr Saatchi is a “perception manager” of distinction. More than most he understands the value of presentation over content. Like many religions, a love of most fashionable contemporary art requires blind faith. You have to believe in it. And if a high priest of contemporary art, like Charles Saatchi, gives his blessing, the rest will inevitably follow.

The art market is impervious to brickbats from art critics. The main players in the game - the Tate, the Arts Council, the British Council, the big auction houses and no more than half a dozen hugely rich and influential dealers, know that artistic reputations are forged on the news, fashion and features pages of newspapers.

I can't help thinking that in the case of Carla Busuttil, all of whose paintings he bought this week, even Mr Saatchi will have his work cut out making a silk purse out of this. Busuttil's pictures are infant-like daubs of faces and figures. By any known yardstick for evaluating figurative painting they are atrocious - indeed they are unworthy of any academy and one wonders what criteria might have been used to award her a degree at all, let alone a postgraduate one.

But don't underestimate Mr Saatchi's aptitude for persuasion or his influence in making sensible people see quality that isn't there. He achieved such a triumph before when he was the first buyer of an execrable painter called Stella Vine. Her work is still jaw-droppingly inept, but she sells it for high prices and exhibits in important galleries. She is famous.

David Lee is editor of The Jackdaw

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