Every summer people are given the opportunity to talk nonsense about the Man Booker Prize; and every summer they take it. Last year, for instance, we heard about the triumph of "historical fiction", the reason being that most of the novels that were shortlisted - and the eventual winner, Hilary Mantel's Wolf Hall - were set in the past.
By this year's standards, that looks like literary criticism. When the longlist was announced in July, much fuss was made over Martin Amis's "exclusion" - an event that is hardly unprecedented. We were informed that Christos Tsiolkas's longlisted The Slap was misogynistic (or, at any rate, that India Knight thought so). Perhaps silliest of all was the claim that this has been the "funny" year: Andrew Motion and his jury have decided on a shortlist that, as he weirdly put it, "might connect with other ways in which comedy has joined the mainstream (stand-up, 'youth culture' and so on)".
If we look a little closer, we discover that this characterisation derives largely from the presence on the shortlist of The Finkler Question by Howard Jacobson, though readers disappointed or even appalled by this book - we do exist - might argue that it is "comic" without being funny. In fact, 2010 might more accurately be described as the "non-funny" year, given the number of comedies - most of them historical! - that might have made the longlist but didn't: Andrew O'Hagan's The Life and Opinions of Maf the Dog and of His Friend Marilyn Monroe, Roddy Doyle's The Dead Republic, Jonathan Coe's The Terrible Privacy of Maxwell Sim and Ned Beauman's Boxer, Beetle.
There is an understandable tendency to search for pattern or meaning in a process that stands only for itself. Five people read 140 novels by writers, discuss their virtues, and choose the ones they quite like, like a lot, and like the most. If their favour shines on "first-timers", say, or "satire", it is a coincidence: those books might have been published a month earlier or later, and a different jury may have overlooked them. Myths of the prize's spiritual unity, such as "the Booker novel", represent an attempt to ward off randomness.
Anyone can develop a Booker theory, with examples adduced from across the years. For instance, I find something suspicious about the tendency of juries chaired by MPs to commit baffling oversights. George Walden managed to preside over a shortlist in 1995 that didn't include Penelope Fitzgerald's The Blue Flower, and Gerald Kaufman's jury (1999) overlooked Tim Parks's Destiny.
This is a coincidence, but the failure to recognise two such adventurous English novels nevertheless feels telling. Booker juries tend to favour the parochial in English fiction at the expense of the tempestuous and taxing. For instance, Howard Jacobson's exorbitant masterpiece Kalooki Nights, longlisted in 2006, would have made one of the most deserving winners in the prize's history; The Finkler Question, by turns mean-spirited and sentimental, its prose a chaos of failed gags and irrational syntax, has none of that book's elegance, energy, or wit.
The Finkler Question is also a conventionally built novel published at a time when there has been much discussion about the novel's - especially the English novel's - formal and philosophical complacency. This year's judging process has taken place against the background noise of a (sort of) debate, its most prominent contributor being Tom McCarthy, one of the shortlisted authors.
McCarthy's C, despite the frequent excitements of its prose, is not much of an intervention; and though it wouldn't make an absurd winner, such a victory might have a damaging effect on the public discussion of literature. McCarthy has already developed a habit of using the pages of the Guardian to offer constricted interpretations of works of literature (Blake's tyger "really represents . . . the Industrial Revolution"). He also enjoys claiming for his tradition any writer he fancies, though it doesn't always come off.
For instance, when he tells an interviewer, during an attempt to portray the Rabbit books as "totally European", that John Updike "studied in Paris", "read Blanchot and Bataille and Beckett, especially Blanchot", and "got a taste for that abstract sensibility", his case rests rather heavily on the claim that Updike studied in Paris, which is nonsense, and admired Blanchot, whom he read with a mixture of scepticism and bewilderment - having already written three Rabbit books. Updike's piece on Blanchot was in fact the site of a succinct argument against McCarthy's kind. "Among the charms of anti-realism," he wrote, "let us not overlook - for its practitioners at least - a certain slippery ease."
Slippery McCarthy has written a chilly novel, but it doesn't suggest a new direction. There are, however, transfixing books on this year's shortlist: Emma Donoghue's Room, narrated by a five-year-old locked in a shed with his "ma"; Andrea Levy's The Long Song, which takes the form of a memoir by an elderly ex-slave; and Damon Galgut's In a Strange Room, a trio of linked parables narrated in the third-person present tense with occasional lurches into the first person.
A victory for the shortlisted book I admire most - Parrot and Olivier in America - would make Peter Carey the first three-time winner of the prize. This doesn't seem an excessive accolade. When it was suggested that the Booker Prize open its doors to American novels, some objected that the Americans were too good, that Philip Roth would take the cheque home every year. But under the present criteria for entry, there are two writers, Carey and J M Coetzee, who have that kind of eminence.
I think the prize will be given to Jacobson or Donoghue, and it will symbolise nothing but this particular jury's decision, be it unanimous or a source of harsh conflict. The only thing as aggressively tedious as pre-Booker patter is the post-Booker conjecture.
But this is just another view, no less partial than Motion's or McCarthy's. The Man Booker Prize is a mere literary toy, any Booker chat just vicarious play. The real test of a book's value occurs in the wider world, and over time: whether it gives pleasure, whether it survives.
The winner of the Man Booker Prize will be announced on 12 October
Leo Robson is the New Statesman's lead fiction reviewer