IN JAMES Kelman's play The Art of the Big Bass Drum (Sunday Play; Radio 3) there's a character called Colin who holds forth, yet holds back. But he doesn't retreat into silence - the debates he instigates and the needling he offers

the assembled company of post-pub, late-night companions are almost always in sardonic disguise.

Cod-Latin and sub-Shakespearean phrases and metaphysical forays wear verbal inverted commas, flicking on and off like neon bar signs.

This could be really irritating if a guy in a pub talked to you this way. You'd want him to drop the curlicues; the archness of speech would get in the way and chances are you wouldn't accept another pint. But within the knowing crafted world of this play, another response happens. It's the realisation that an utterly familiar thing has been brought into rare focus; this is what the best artists do.

If language were neutral and all concepts and vocabularies simply there for the taking, then why would Colin talk that way? Why would he internalise a sense that certain registers, certain metaphysics, have to be appropriated with mockery and funny voices rather than just entered? Because the goodies aren't really on offer and any quest for clarity has to weave and bob around the pretence, and bear witness to the fib.

One of the many reasons I find the Philistine puritan response to Kelman's writing pathetic in its

prissy worries about ''bad'' language and accessibility is in the baleful display of its own ignorance. As if to say, ''These alienated swearing inarticulate losers do not represent us - You are letting the side down.'' (A bit like asking Beckett to look on the bright side, or Wittgenstein to stop that obfuscating.) But the consciousness-stream of the characters relentlessly appraises the allotted marginal status, knows the judgment better and more intimately than the

middle-brow jury. The self-interruptions or sudden dropping of a line of thought, the brutal dismissal of a bogus notion, have a ferocious integrity. Colin prefers to sound disconnected than inauthentic. Like a dissenter left only with the rightness of his cause, language acquires a kind of conscience. There are certain things it cannot say, or cannot say in a neutral way, without betrayal.

The familiar Glaswegian terror of sounding pretentious is under the microscope here. Under Kelman's inspection he shows us something more than a

dislike of pomposity. His fictional people know the discourses barred to them; the subtle brutal operations which have divided up the linguistic territory. They can either translate themselves out of existence, or zigzag in and out with sometimes uncomfortable self-consciousness. Colin is caught in his own zigzag - and pulling himself apart in the process. Kelman details that process unswervingly and we have to listen carefully because it's a complex and important endeavour easily overlooked when the metaphysician is mistaken for a documentarist.

How we explain ourselves to ourselves is at the heart of philosophy and is also the beginning of our communication with others. The play reveals what form the human instinct for inquiry and for conversation takes in the exchange between four specific men in a present historical moment. The result bleakly suggests they have been given a dismal hand of cards but that they have to play somehow with what's been dealt.

Douglas Gifford's introduction to the play suggests that there is a wisp of affirmation at the end of the play in the image of cracks appearing in the sky. Certainly the belief that there are questions that never get asked is solidly in place, if solace can be gained from that. Desolation and paralysing rage have not duped the protagonists completely on that score, which in Kelman's non-negotiable materialist vision, is the last bleak victory - or the starting point of resistance.