Visual Arts: Dreams in the corridors of power

Back in the days of continuous screenings, filmgoers knew about taking the plunge. It was, more or less, normal practice to enter a cinema in the middle of the programme. You did your best to pick things up and stayed on until you reached the point in the next screening where you come in, all the film was seen, and then you left.

Nowadays our behaviour is more orderly. We start at the start and leave at the end. We'd consider it wrong to treat film as basically cyclical, something that can be begun at any point, and enjoyed as (say) a climactic action followed by a long, explanatory flashback. Nowadays only porn cinemas, where linear narrative isn't so important, operate on this drop-in basis.

Porn cinemas and fine art video installations. Here again, the viewer makes the opening move. You must take a plunge and you find yourself standing in a flickering darkened space, among people who have been their longer, not knowing quite what's going on.

So here we are, plunged, and standing in a flickering darkened space. Set in one corner, at right angles to each other, are a pair of projections, ranged floor to ceiling. (There are two more, arranged in the same way, in the opposite corner behind us.) At this point the cameras are ploughing, at bum level, through two sharply perspectival views of continuous, unoccupied leather seating - skimming along high-backed, tightly stuffed benches, one green and sewn down in quilted ribs, the other red and buttoned into deep puckers.

The rolling symmetrical vista makes for a Pearl & Dean effect, suggesting endlessness. The green one is a front bench from the House of Commons, the red one ditto but from the House of Lords.

At least, I recognise the Commons furniture from TV, and from having gone there once. The Lords I don't recognise, I just guess, knowing this video was made in the Houses of Parliament. The video doesn't say, of course. A documentary would and might explain what heraldic symbolism is involved in the colour coding and what tradition is embodied in the divergent upholstery. It might, but actually a documentary is unlikely to make much of such basic, interesting, sensuous facts.

This was one of the good bits from the Jane and Louise Wilson exhibition at the Serpentine Gallery. Jane and Louise Wilson were born in 1967. They are twins. They work as a single joint artist. Their work often features themselves. They are both on the shortlist for this year's Turner Prize. And they've been the subject of many journalistic profiles lately, so you may know all this anyway.

The show has three short video projections. Each has its own room, and runs for about six or seven minutes, in a continuous loop. Each one consists of four simultaneous, co-ordinated video projections, arranged as described above - L-shaped pairs of projections in opposing corners of rectangular rooms. You can (if you put your back to a wall) see three screens at once; there's always something happening out of vision. It is pretty clear exactly when the videos stop and start and each, I would say, needs to be seen about three times. Give it an hour in total.

Each video deals with a site of power, deserted. The first, Stasi City, was filmed in the abandoned HQ of the former East German secret service in Berlin. The second, Gamma, was filmed in the abandoned US air force base at Greenham Common in Berkshire. The most recent, Parliament (A Third House), was filmed at Westminster during the summer recess.

They are visually interesting locations. What large institutional building isn't? They're the sort of places where anyone with a camera might have fun. The Hohenschonhausen prison is, like many things from the former GDR, cruddy and old fashioned, with terrible B&B furniture in the "interview" rooms, and quaintly period paternoster lifts and revolving filing cabinets. The Palace of Westminster is like some pompous grand hotel, every little cubby hole crested and bossed, so as never to let you forget where you are.

It's the intimacies of these places which the Wilsons focus on. You don't get any idea of the size or layout of the buildings. The intimacies, and those bizarre things which, of course, stay unexplained. What on earth is that piece of tree trunk with eye holes cut in it in the Hohenschonhausen? Was it really used to conceals spies in forests?

Obviously, they are politically charged locations too. But to those who may fear that some comparison is being made between a prison in a former totalitarian state and the Mother of Parliaments, and equally to those who might welcome that comparison, I should say that as far as I could see the political content of these pieces is pretty well nil. Even a qualm that the artists might be exploiting political resonances in their chosen sites doesn't get much purchase. You can look for attitude. But the videos seem to be primarily interested in certain motifs and spatial effects: in openings and glimpses, in things that go up and down and things that go round and round, in lights going on and off, in mirrors, symmetries, tunnelling perspectives and pointing arrows and in matching camera movements. The all-round four-image simultaneous editing can sometimes become involving, though often you don't seem to be missing much if you just concentrate on one pair of screens.

Or perhaps it's true to say that the films try on various attitudes, without settling on one. Sometimes it feels like they are giving these places a haunted-house-cum-surveillance-paranoia treatment. Sometimes you get hints of a more cerebral analysis of the architecture of security and bureaucracy. Sometimes it's like an I-spy guide to curious details. Sometimes like an inquisitive, exploring home movie.

The compound effect of this is to produce something coolly weird, disassociated, disoriented. What's strange and what's normal get blurred. Likewise what was truly found and what was added. The word in short is "dreamlike". And when the artists themselves make brief appearances - mysteriously levitating in one of the Stasi offices, or dressed in air force uniform and marching purposefully down a mirrored corridor at Greenham - that mood is made clear.

The dreamlike: this is of course the artistic mode, the universal cliche. (Surrealism: we've got to get it out of our heads.) Now you may say that these places of power were, or are, themselves dreamlike. But that isn't really true. It's just a spectatorial take on a perfectly rational, if malign, operation.

Or you may say - on the other hand - that weaving a fantasy is a way of overcoming the power of these places, but that's just rubbish. Like the Greenham women dancing on the silos. I mean, you could have various other arguments about these videos, but they would always exceed their object because the videos themselves don't seem to have thought through what they're up to. And really, just as pure formal films, though they have their moments, they are a little bit boring.

Jane & Louise Wilson. Serpentine Gallery, Kensington Gardens, London W2. To 31 Oct. Open every day. Admission is free.