"No disrespect to art intended, but you can't just designate a 'religious' role to it." Tom Lubbock reviews the Tate Gallery's ambitious new exhibition, 'Rites of Passage'

Door-stepped or button-holed by religious evangelists, it's struck me that, just to return the favour, one should be able to make some retort like: "But have you, for your part, ever considered trying art? There's a lot of us find it makes a big difference to our lives." When it comes to it, though, I couldn't do this with a straight face - not from any lack of faith in art as such, but because it would imply the wrong kind of faith in it. And one doesn't want to go leading evangelists up the garden path.

People have said plenty about art somehow taking the place of religion. They also point out that, in other cultures, the two haven't been so distinct - and they speculate that, in ours too, art (in some sense) and religion (in some sense) might come together. A new show at the Tate Gallery, Rites of Passage, entertains this kind of thought.

The exhibition, its curator Stuart Morgan says, "proposes that artists have an important role in society, that they be considered as passeurs, priests (perhaps) of that secular religion that art has become." Passeurs means, roughly, border-guides - people to help us pass through our life- crises, personal, social and even historical (the subtitle is "Art for the End of the Century"). So that passing through this show of sculptures, installations and video-pieces would be itself, ideally, a rite of passage, or several.

I doubt it. True, I'm not sure what, as things stand, do constitute our "rites of passage". Weddings? House warmings? Apprentice printers having their genitals dunked in ink? People have sometimes tried to invent their own. I can see it might be good to have a few more serious ones. But - no disrespect to art intended - you can't just designate this "religious" role to it. The culture has to agree. I suspect Stuart Morgan doesn't quite believe it either. But the idea is too interesting to brush off as a curator's fancy. It's worth thinking what it would mean, if it were true.

It might mean, for one thing, that there'd be no reviews of Rites of Passage, not in the normal way. You wouldn't say: here is a thematic group- show of work by 11 contemporary artists - a new departure for the London Tate. Nor: how welcome that Louise Bourgeois, the US sculptor and installer, is getting at least this small showing here, because her work has been inexplicably neglected by our galleries, except once at the Riverside in 1990 - though really a retro is what's needed, but they had one in America last year, so we've probably missed the chance. Nor: I'd always thought that the US videoist, Bill Viola, was madly overrated, compared say to the US videoist Gary Hill, but his piece here is a beauty.

No, if you took Rites of Passage in the intended spirit, you wouldn't talk like that at all. If art were a kind of religion, artists its priests and art-works its rites and emblems, the usual critical / consumerist approach would be out.

You wouldn't see work as being by individual artists with their individual points of view. You wouldn't see yourself as a viewer, more as a communicant. You wouldn't talk of hits and misses - that would be as odd as saying "The Mass, I'm afraid, just doesn't quite work for me. Extreme Unction, on the other hand..." But what would you say?

It's quite true that, content-wise, these works are about rites-of-passage subjects and evoke ideas of transformation: growing up, getting sick, dying, moving into another epoch; much dying. In the Viola piece, Tiny Deaths, you enter a darkened room (try to find yourself alone there). On three walls, hazy interference images are projected, with shadowy human presences lurking in them, which you might take for your own shadows. For a brief second, these shadows resolve into bright living images of people, then suddenly burn out white - gone in a flash, back into the haze.

You go behind a partition to meet Robert Gober's Door with Lightbulb, a shut door in a wall. Again, it looks like death, an emblem of terminal separation. A light shines from the other side (someone's within), a red bulb glows on the wall above (don't enter), bales of newspapers are stacked on the floor (hasn't been opened for ages). A gallery cordon prevents you approaching and trying the handle - but then you know, though half- forget, that there's nothing beyond anyway, only the rest of the gallery you just came from. It has that high altar effect (go behind it, God's not there).

Or there's Mona Hatoum's Corps Etranger, a little rotunda-shrine you stand in, with a circular screen at your feet, like a pond. It shows the view from an exploratory micro-camera as it plays closely over the skin of a woman's body, and then plunges into each orifice by turn and probes deeply, tunnelling the oesophagus, the uterus, the colon (thoroughly irrigated): an eye-opening, mouth-opening experience. The entry moments are amazing, when outsides turn - at what point? insides, and the whole body, in or out, becomes a single continuous surface.

These three pieces use their settings to put the viewer in a communing position, not spectating but - imaginably - taking part in some rite of death or therapy. Elsewhere though, it's business as usual, the normal modern art gallery thing: walking around, taking a look at objects standing on the floor or hanging from the roof, each artist's work discretely segregated in its own area; I've seen several shows installed far more ritualistically. They haven't quite found how to place Bourgeois' Red Rooms, two "private" spaces, little theatres of childhood memory, filled with emblems, which you can just peep into. They ask to be approached with some curious trepidation; here you just bump into them. Her work looked much more sacral, and much more intimate, at the Riverside.

But in the end it's not a question of staging. Almost any art-object, by some stretch of the imagination, could perform a ritual role. Most museums are full of things, like icons and totems, that in other contexts once did. It's no reflection on the power of the works here - I've described what I think are the best ones - to say that they aren't rites of passage, or rites of anything, not really. The context of custom and practice is lacking. Quasi-ritual works abound in modern and contemporary art. But they are still, unredeemably, works of art.

To be sure, art can "change lives"; some works, for some people, sometimes, on an individual and unpredictable basis.

Maybe some here have, or will. But to call them "rites" is to make into a function what's a matter of experience. Someone who's just got married has no choice, for the moment, but to be married. Someone who goes to an exhibition may leave changed or unchanged.

Come to think of it, would we want it, this religioning of art, even if it could be brought off? Would it involve submitting to art's authority as a whole, with no picking and choosing - or not at all? Would you have to decide whether you were in or out of the fold? Might the Tate start issuing anathemas against art-apostates? I see it's meant in a helpful way, but you never know where things may lead.

n 'Rites of Passage: Art for the End of the Century' is at Tate Gallery, London, SW1 (0171-887 8000) Sat 10am-5.50pm, Sun 2-5.50pm to 3 September, pounds 4, conc pounds 2.50