Samuel Johnson, in one of his great aperçus, responded to some pettifogging critic with the phrase: "A fly may sting a horse, but the horse will still be a horse, and the fly no more than a fly." That sentence sprang to mind the minute I read that Paolo Coelho had decided to take James Joyce to task. In an interview in Folha de S Paolo (one wonders if he chose that outlet for any particular reason) the self-proclaimed "literature wizard" contends: "Today, writers want to impress other writers." He then names the culprit: "One of the books that caused great harm was James Joyce's Ulysses, which is pure style. There is nothing there. Stripped down, Ulysses is a twit."

Coelho is, of course, entitled to his dumb opinion, just as I am entitled to think Coelho's work is a nauseous broth of egomania and snake-oil mysticism with slightly less intellect, empathy and verbal dexterity than the week-old camembert I threw out yesterday. But the attack is, inadvertently, interesting. Coelho is not the first to attack Joyce: Roddy Doyle has, Alan Bissett has, and Dale Peck made it the central, rotten plank of his sour and sanctimonious anti-modernist criticism. Whenever there is a reactionary attack on contemporary literature, a snipe at Joyce is necessary.

What are the criticisms? Joyce, they claim, writes for writers – not, presumably, readers. His works are sustained by a cerebral clique that – whisper it – don't really like them either, but use them as a trump card in one-upmanship. Joyce is "difficult", Jonathan Franzen's catch-all term of dismissal.

Only someone who had barely glanced at Ulysses would damn it for "pure style". It is an utter come-all-ye, salmagundi, snarl and macédoine of styles (Johann Wolfgang von Goethe famously said he didn't have a style, he had styles, a motto many aspirant writers in search of their elusive "voice" might adopt). Coelho – let's give him the benefit of the doubt – may not be complaining about the glorious polyphony of Ulysses. The exuberant styles might conceal a lack of import. As he says: "There is nothing there." In Joyce's defence, I would say there is love, grief, anger, lust, generosity, small-mindedness, kindness and redemption as well as kidneys, dogs, claret, soap, what-the-butler-saw machines, classical statues, menstrual blood and brogues. But maybe Coelho isn't placing style against content but style against message. Maybe Ulysses can't be summarised into a sentence-long quote such as: "Remember that wherever your heart is, there you will find treasure." Perhaps life is actually a bit less pat than that. Maybe Coelho was confusing Ulysses and the 1981 cartoon Ulysses 31.

Coelho gives the game away when he brags that he is "modern" because he can "make the difficult seem easy". I think it's an ethical as well as a literary proposition that anything that aspires to make the world and the people in it less complex, less paradoxical, less multifarious, is a kind of dirty little libel on reality.

The real slander is to the reader, or rather, to readers. Note how the anti-Joyceans have all read him and then tell readers he's not for them: too difficult, too abstruse, too weird – with the "for you" hanging in the background. I've been there, they say, and you wouldn't like it. It is an attitude that surreptitiously belittles the reader. There is nothing as profoundly patronising as a middlebrow, supposedly "literary" author on a soapbox. (Ian Rankin, bless him, has always taken any opportunity to enthuse about Thomas Pynchon as much as Denise Mina.)

There are high modernist books that take effort – Christine Brooke-Rose's Thru, or William Gaddis's The Recognitions or Hermann Broch's The Death of Virgil – but I've never yet read one that didn't repay the effort. On the other hand, I've read plenty of unambitious fiction that didn't reward me turning the page. Coelho and his ilk create a cocoon of their own limitations, and insist everyone outside it must feel and think like them. Writers and readers of worth know the real point of literature is, as Louis MacNeice so brilliantly put it, that the "World is crazier and more of it than we think,/ Incorrigibly plural".