The poster for the British Art Show 7, and its gallery signage, positioned above the door of London's Hayward Gallery, depicts a naked young man sitting on a metal bench.
He is staring at a small fire burning at one end of the bench. It seems important to have this image in your head, because when you arrive at the bench in the exhibition – it's a work by the artist Roger Hiorns – it will likely be empty: no boy, no flame. They only appear once a day. This is maddening – I want to see this callow youth and his magical fire! But I like this work. It's like a small firecracker, a revelatory moment or a tender adolescent memory: it can only appear briefly without losing its lightning beauty. Moments like these are rare. And, if we're honest, the moments in which we are truly moved by art are rare, too.
The British Art Show is a quinquennial touring exhibition which is supposed to corral together the British artists who have created such flashes of éclat over the previous five years. For this edition, the curators, Lisa Le Feuvre and Tom Morton, have chosen a subtitle: In the Days of the Comet, taken from the title of science fiction writer H G Wells's 1906 novel in which a comet releases a green gas over the United Kingdom, inaugurating a kind of mass spiritual and intellectual revolution in mankind – a "Great Change".
This exhibition of 39 artists is, of course, a reflection of the curators' tastes and interests as much as anything else, but they have created an incredibly thoughtful show including the work of several brilliant artists. Today's artists, like Hiorns, appear to be searching for moments of transcendence amid a world that is as crazed, lurid, demented and, above all accelerated, as it has ever been. Christian Marclay's 24-hour long film The Clock has already been roundly praised, following the film's screenings at London's White Cube gallery last year, but it's a wonderful, epic work that is a genuine pleasure to watch. It's a film collage of the time, as depicted in cinema – people checking their watches, bombs about to go off, bell chimes and hot dates, so that one could, logistically, use the film as a clock. Cinematically strung together, and full of building tension that never quite breaks, this work also gives one the curious ability to watch the passing of time and the rhythms of life as a collective experience.
Wolfgang Tillmans has presented a collection of newspaper cuttings and clippings on tabletops, detailing our incredibly confused society – outlandish cruelties, torture, homophobia and extreme plastic surgery. Hanging behind them, however, is one of his large abstract photographs, Freischwimmer 155 (2010), a billboard-sized image of green colour in various states of depth and intensity, which is run through with fine black lines and strands like musical staves and notes, that have been finally freed from one another to run with the tides and the wind, and which epitomise some kind of freedom from what is being depicted on the tabletops.
There's something restful, too (albeit rather funereal), in the formal elegance of Karla Black's sculpture Brains Are Really Everything, a square plateau made from soil in layered shades of deep blackish brown and a rich cocoa. Atop this is scattered yellow pigment powder and lumps of red and yellow soap. These look a little like half-eaten apples degrading, and this layer of intense colour creates the impression that brightness and beauty is sinking into the earth as though it were paint on a canvas. Phoebe Unwin's paintings have a slow-burn quality, too – External Outline of a Thing (Head) is a vague rendering of a head in melancholy bathroom shades, topped with thick smudges of waxy, fatty paint in an ambiguous shade of eau-de-nil. Luke Fowler's films A Grammar for Listening pull the soft, fuzzy noises of various ephemeral moments – water running over stones, for example – and closely record the sounds, playing them at dramatic levels alongside faded, luminous footage. A film of a walnut burning, with the volume turned up loud, sounds like screeching car brakes, squeaks and footsteps in the snow. As the flame dies, the charred nut now black and shrivelled, it seems like the story of a tiny death.
There is also a certain anthropological impulse that unites many of these artists, as though they are trying to hold up objects from our world and turn them in a strange light, in some kind of skewed version of A History of the World in 100 Objects. Matthew Darbyshire treats objects from the present – some kitschy furnishings such as pink egg chairs, based on the designs of Arne Jacobsen, sequinned Union Jack cushions and comedy bookends – as though they were able to show us some intrinsic truths. Darbyshire often creates work that explores the bridges between public space or culture and corporate interests, but gathered together in an installation entitled An Exhibition for Modern Living (named after a 1949 design showcase at the Detroit Institute of Arts), this piece of magenta fluff and chrome gestures primarily to issues of taste. There seems to be some contempt here, about those who purchase objects of such "low taste", which I find troubling – there's only disdain in this work, not the surreal, disturbing or sublime that marks the work of those American forbears who created art with the banal products of popular culture: Jeff Koons, Haim Steinbach and Mike Kelley. The fact that these items are on sale in the Hayward's gift shop as some kind of ironic good-bad-good purchase also sits very uneasily.
A more hysterical anthropology is present in Elizabeth Price's wondrously delirious film User Group Disco, in which another set of products from this era – banana racks, ornaments, pet feeders – spin around on the screen accompanied by a bombastic text rendered in the style of Photoshop presentations, announcing that these objects present a horrific theory of the universe. Nathaniel Mellors presents a more chewed-up vision of culture put through a surrealist mill in his hilarious soap opera Ourhouse, which seems like a Beckettian vision of EastEnders. A sculpture of a head, attached to a pump, constantly regurgitates its own pale blue vomit: a visceral reminder of art's tendency to eat itself.
While it's impossible to sum up, in a broad sweep, the changes in art over the last five years, it's clear from the sheer quality and range of work in this exhibition that British art is currently in a healthy state. The broader acceptance of contemporary art over the years since, say, Tate Modern opened, coupled with London's growth as a market centre, have meant more funding, more opportunities, a high standard of practising artists teaching in art schools. Artists appear to have less to prove – they don't have to shout to be noticed.
British Art Show 7: In the Days of the Comet, Hayward Gallery, London SE1 (www.southbankcentre.co.uk) to 17 April, then touring