Doodles on a work of art

John Guare has adapted his play Six Degrees of Separation for the cinema. Nice try, says Adam Mars-Jones

One of the running jokes in Six Degrees of Separation is that when the impostor Paul, seeking to overcome the considerable disadvantages of being black and poor and gay, cons his way into the lives of various sophisticated and wealthy Manhattanites, his strongest weapon turns out to be the offer of parts as extras in an imaginary film version of Cats. Lloyd Webber is now so fully assimilated into American culture that Lloyd Webber-bashing has become a pet pastime on more than one continent. No one in the film has a good word to say for Cats on stage, but they can't pass up the chance of a brush with glory, and so what they say, as if they were simply keeping an open mind, is "film is a different medium".

Well, film is a different medium, and John Guare's original play (adapted by him for the screen, directed by Fred Schepisi) is fully as theatrical in its own way as Cats. For the first quarter-hour or so, it looks as if the transposition won't come off, with film grammar and stage dialogue pulling in different directions. The camera keeps moving away from Ouisa Kittredge (Stockard Channing), and her husband Flan (Donald Sutherland) as they entertain friends with their self-mocking, slightly smug account of the evening before, when a young man burst into their apartment with a knife wound, saying he had been mugged. The intruder turned out to be a college friend of their children, highly charming, an accomplished cook, and the son of Sidney Poitier to boot. The camera's stylised retreats from the actors' faces may be intended to prevent any too indulgent identification with the characters, but the effect is only to make their dialogue seem stagey. The couple's telegraphic repeated phrase about the danger they now realise they were in - "throats slashed!" - sounds like a Noel Coward line stranded far from home. Yet the story begins to exert a genuine grip, even if the camera never quite grows out of its bad habit of revolving slackly round the characters, as if to remind us that we can't be in the theatre, where we wouldn't be able to rotate in this way.

When "Paul Poitier" (Will Smith) offers to cook dinner in the Kittredges' apartment, it turns out that a rich person's idea of there being "nothing in the kitchen" is not everyone's. The fridge is piled high, and Paul turns out a wonderful meal for his hosts. As Ouisa remarks in apparent innocence, "it's such a treat to eat at home".

You might think that a film or play containing that deadly line was condemned to being a satire, but the distinctive thing about Six Degrees of Separation is its mixture of the sharp and the sweet. Yes, these rich people take in an impostor because they judge him by superficials (jacket, accent) and also because, if you must know, they would like to play extras in the film version of Cats, just for the fun of it. But they have other reasons that aren't so discreditable: Paul describes their children to them not as they are but as their parents would wish them to be - quietly, fiercely proud and loyal. Paul also offers them the vision of a black person undamaged by racism, and it isn't entirely self-serving to grasp at that.

One of the film's themes is the precariousness of American self-invention. Flan's discreet art-dealing business is always in danger of collapse, and he and his wife describe themselves not as rich but as "living from hand to mouth, on a higher plateau". On the night that Paul burst into their lives they are actually trying to get a canny South African businessman (Ian McKellen in cameo mode) to make an investment they desperately need.

The film's situation is based on a true story (a true story of imposture, that is), but unusually for a fact-based piece, it positively bristles with themes: imagination, idealism and illusion, for starters, and the relation between the three. The mutual imaginative dependency of insiders and outsiders, for afters. Then there's the melancholy notion that acting as a parent or a child is much easier for people who are not in fact related. Having a child may be the closest some people get to making a dream real, but unfortunately a dream that answers back is more like a nightmare.

There are further themes that risk cluttering the imaginative space of the film, themes to do with art and value. The very first images of the film are extreme close-ups of brush strokes from paintings, and Flan Kittredge's job of turning creativity into commodity is almost crashingly relevant. Flan, when he first sees "Paul Poitier", is looking at a slide of a Cezanne. His eye moves from one reproduction to another. So: is art a lie? Can a lie be art? Is art a pure pattern or does it always tell a story? Does turning something into a story (as the Kittredges do with Paul throughout the film) betray its truth?

The art-theme must be thanked for providing Schepisi with his single most cinematic sequence, which shows Donald Sutherland's bleached-out face addressing us while the camera prowls the halls of a primary school. Flan remembers trying as an adult to join an art class for the second grade - second grade, where every child is a little Matisse. He pleads with the teacher to tell him her secret and all she says is, "I don't have a secret, I just know when to take their paintings away from them", an answer that is both disappointing and perfectly satisfactory.

Many of the ideas that the dialogue rehearses have already been realised, in any case, by the art direction (the production designer was Patrizia von Brandenstein). We know, for instance, that Ouisa has been deeply thrilled by meeting Paul from the red dress she wears the next day, which carries on the rich tones of the Kittredges' apartment the night before. Later on we know that she has grown away from her peer group, before she opens her mouth to say so, by the contrast between her pale lemon outfit and the surrounding formal black.

Somewhere along the line it may be that John Guare remembered Pasolini's Theorem, with its intruding angel who seduces and destroys. Otherwise the artificial darkening of tone towards the end of the film looks like an odd loss of confidence. Six Degrees of Separation is more truly serious before it feels the need to include a death. Perhaps it's just that someone should have taken Guare's script away from him, before he covered-over some of his best ideas, and produced beautiful doodles right up to the edge of the paper.

n On general release from Friday