Both theoretical physics and a French philosopher inform the work of artist Grace Weir. In her current show, the more she tries to pin down a tiny incident, the more elusive it becomes

The artist Grace Weir was one of the official Irish representatives at last year's Venice Biennale, where her ambitious video work, around now, attracted much positive attention. Her current exhibition at the Model Arts and Niland Gallery, in Sligo, not only features a new work, The Turning Point, and a work in progress, it also incorporates around now and six other pieces made over the past five years or so, making it a good representative exhibition of her recent output. It is also the Model Arts and Niland's first large-scale multi-media show, and proves that the gallery is an estimable venue for multi-media.

A little over a decade ago, Weir was making sculptures that are like fragments of an archaeology of the future, fossil beds stocked not with the traces of organic life, but with mechanical and electronic pieces. In retrospect, it is possible to see that certain preoccupations evident in this work, including time and fragmentation, indicated future areas of concern, but even looking at it now, it is difficult to see in it signs of the direction she was to take.

Man on Houston St, from 1996, marked an epiphanic moment. As she recounted it to Tanya Kiang later, she was making her way along Houston Street in New York, snapping various architectural details as she walked. A voice broke through her concentration as a man shouted at her: "Hey you, take a picture of me!" Her reaction was: "Panic. Lift the camera . . . Just take the snap. Then run away, take flight . . ." This split-second encounter became the enigmatic centrepiece of a hundred-strong array of photographs.

These photographic prints seemed to employ every possible imaging device, ranging from satellite surveillance to the level of subatomic particles, perhaps in the cause of producing a kaleidoscopic portrait of one moment in time.

Perhaps, again, this whole project triggered her more recent work, because one implication of Man on Houston St is that the more she tries to pin down this tiny, insignificant incident, the more elusive it becomes as a moment experienced from the inside. It is as though she had stumbled on an uncertainty principle of her own.

As an artist dealing in representations, objects, workable equivalents of the world of facts and lived experience, she had assumed a certain level of connective accuracy. But this assumption was undermined by the realisation that the images and things somehow missed out on the in-between, where everything actually happens. She came to feel that while, as an artist, you could bring a battery of methods and media to bear on an event, the event itself eluded whatever you made of it. To the extent that you could pin it down, you made something else of it. One effect of this was to point her away from the media she had been using, towards time-based video and film.

There are two recurrent, and by no means complementary, reference points to her thought processes since. One is the engrossing, difficult area of theoretical physics, and the other is the work of the anti-systematic, nominalist French philosopher Gilles Deleuze.

From her point of view both, via radically divergent analytical approaches, point towards the extreme disruption of what might be termed the basic fabric of perception, our tacit understanding of how we see the world of people, things and events in which we live.

The appeal for Weir of Deleuze's radically anti-subject, fragmentary views of hierarchies and coherence is fairly clear, as potentially offering a way to break up the familiar patterns of thought which allow us to package experience and even our notion of "selves". But what of the rational materialism of science?

The idea of breaking down matter into smaller and smaller particles, until you reach the smallest fundamental building blocks, is surely incompatible with her aspiration to find a way into the indeterminate spaces between the hard edges of measurement, definition and representation.

One of her pieces, Distance AB, is actually about this very point. Just as the amorphous mutability of a cloud eludes the strictures of Renaissance perspective , so what Weir calls "the event space" of the lived moment eludes the apparatus of mediation and representation. Or, while certain spatial phenomena transcend the Renaissance mastery of space, certain temporal phenomena transcend the ubiquitous temporal media of the electronic age.

Here, as it happens, developments in theoretical physics are more supportive, in an analogical sense, of Weir's ideas than we might initially expect. In a work in progress, The Darkness and the Light, a physicist asks what would happen if we take a piece of paper and keep halving it. Very quickly we get down to a molecular level, then a subatomic level. Soon we're among the quarks and eventually, as superstring theorists would have it, we reach the stage where the four known forces of nature, and hence space-time as we know it, unravel, and we are dealing with 10 or 11 dimensions, most of which have previously been coiled up unobtrusively inside our familiar four-dimensional world.

There is, in other words, no end-point, no indivisible absolute space occupied by hard-edged particles.

The work around now remains her best piece in relation to these various concerns. The viewer is positioned between two mobile, vertiginous, aerial views of cloud and landscape. Not only do we find ourselves occupying a distinctly precarious viewpoint, but because we are presented with two opposite directions of movement, it is continually impossible to situate ourselves. If we opt for one, we exclude the other. To maintain both we have to keep negotiating between the two.

The work is a highly enjoyable visual experience. It is, as Noel Sheridan wrote of it, "a trip". That is, it gets us, or aims to get us, outside of language, outside all those symbolic networks of comprehension and control, and disturbs us from what Eric Rhodes once called the "habitual sense of superiority" we have when we look at a cinematic narrative and feel apart from it because we know the rules, we know where it's going. It cuts us adrift for a moment and then keeps that moment going, but of course we inevitably start to analyse and assimilate. Still, around now is Weir's best bid yet to get herself, and us, into the heart of that "event space" she is after.

That's not to say that The Turning Point is not a good, accessible work that could and should be screened on television, or in the cinema, without any loss of impact. "In examining the unfolding of an event in space and time, the role of narrative is central, but it is the viewer's experience as opposed to narrative structure that I am interested in addressing," she has written. Her approach is to use our narrative expectations and to disorientate us by subverting them.

The Turning Point is a tiny narrative that hinges on a twist in the tale, to the extent that it would be unfair to say what that twist is. But, cleverly, what Weir has done is to set up what might be thought of as a conventional narrative framework, and then turn things around so that we are, so to speak, inside the protagonist's experience rather than reading an external story in a habitual way. She uses the fact that we see a character - played by Paul Ferriter - and begin to ask questions about his inner life, only to stymie this line of approach. The weakness of the work is that it is, by comparison with around now, comparatively stilted in its appropriation of the grammar of cinema or television. But that is a marginal quibble.

Grace Weir's work is on view at the Model Arts and Niland Gallery, The Mall, Sligo, until August 5th (071-41405)