Thomas Sutcliffe: How does our garden grow?

I always look forward to the Today programme's occasional cultural debates, not so much for the content as for the dependably comic way in which the producers usually try to stir up a controversy where non exists.

The pattern is now very familiar - the distinguished writer Bill has somewhere made some mild query about the contemporary novel's failure to engage imaginatively with new technology. His equally distinguished colleague Ben is called in to rebut that view by arguing that the novel should have nothing to do with anything invented after 1928. But as they talk, it becomes clear that Bill and Ben don't actually disagree with each other at all and can't be persuaded to pretend they do. The presenter gamely tries to goad them into antagonism - like someone trying to stage a dog-fight with Beanie Babies - but it's no good. They will insist on talking about what they have in common.

There are exceptions to that rule, naturally. There was a sprightly set-to earlier this week when two card-carrying Bob Cats - Andy Kershaw and Mark Ellen - sparred amicably over the quality of Bob Dylan's recent concerts. And just the day before that, my attention had been snagged by another genuine clash of opinion - after the programme had invited the gardening broadcaster Eric Robson to respond to Anne Wareham's proposal that gardens should be reviewed in the same way that plays and novels routinely are. The state of British gardening, she argued, is lamentably dull - and only the threat of 400 withering words from some horticultural Kenneth Tynan was likely to change matters.

I rather enjoyed the idea of a new scope for critical disdain - "Mrs Henderson's hydrangeas attempt to be archly knowing but deliver only a callow gaucheness - and her grasp of foliage counterpoint is little short of disgraceful. This garden does not need a critic, it needs a bulldozer." But Robson did not and was equally dubious about the potential results of the experiment. Every major newspaper carries a daily television review, he pointed out, and just look at the state of television. "I rest my case," he concluded.

Naturally, as a television critic, I felt a little prickle of antagonism. How on earth does he know what television would look like without us, I thought. Honestly - you spend your days battling the electronic equivalent of giant Japanese hogweed and you get no credit at all. It's not as if there's some kind of control that would allow anyone to decide, once and for all, whether we're useless pests or a vital part of the ecosystem. In any case - the argument is dangerously reversible. I listen to Gardeners' Question Time often, and yet my garden is a botanical slum.

What was interesting about his remark - and the suggestion that had spurred it - was the assumption that the critic is useful as a kind of cultural gardener. On the one hand you have the wild fecundity of nature (inspiration, the Muse), and on the other, the restraining virtues of the critic, who prunes and shapes and hoes out the weeds. It's the job of the critic, both implied, to keep an eye on standards and tidy things up.

This seems to me to be a misconception - though I know it's one shared by quite a few reviewers and I can quite understand the desire to believe it. It gets you inside the estate, for one thing - an honoured member of the landscaping team, rather than some negligible peasant hurling handfuls of manure over the walls. And I don't doubt that there are cases where thoughtful pieces of criticism have had an effect on artists - either by stiffening their resolve or by alerting them to some aesthetic pitfall.

But it has always seemed to me an awfully indirect way of going about things. If you want British theatre to be better, after all, why not write a better play or direct one more effectively than anyone else? The scornful answer to that would probably be "Because they can't" - since the other standard model of critical motivation is that of ingrowing creative impulse, turned septic.

But, although no one could sensibly deny that criticism occasionally displays envy (and may, indeed, actually require it, since it's hard to separate from its Siamese twin, admiration), this misses the point about really great critics - which is that they are supreme readers, or viewers, rather than impotent artists. It's not their capacity to shape or alter the landscape that matters, but their capacity to respond to it in all its variety - and to see things that others will almost certainly have missed. What both sides failed to grasp in that Today discussion was that good critics don't show you how to be a better artist; they show you how to be a better audience member.