If the crowds at the Tate's latest Turner Prize show are anything to go by, contemporary art is as popular as ever. And yet, if you regularly visit such exhibitions and bother to read the catalogues and blurbs that accompany the works, you will be all too familiar with the feeling of incomprehension. The text often reads something like this: "The work on display confronts the viewer with opacity, liminality and indecipherability, resulting in a radical break with our normal modes of thought, opening up a profound rupture, at the brink of which our illusory selves can only tremble in the draught of an en-counter with the fathomless other." I exaggerate only a little.
Why, as viewers of art, are we continually assured of the limits of our understanding? What explains the insistence on the unknowability of art? After all, much contemporary art hardly warrants such a description, being no more difficult to work out than an advertising slogan or a crossword clue. Many pieces are claimed to be "about time" or "about death" or "about urban space", and so on, while doing no more than throwing together a couple of conventionally opposed elements and letting the writers of press releases, and the docile critics who spout from them, do the rest. Most contemporary art is immediately recognisable as such, which suggests that it is far more uniform, and understandable, than its propagandists would have us believe.
Contemporary art is the negative image of mass culture. Because artists generally produce one-offs or limited editions (even when using media such as photography and video), they do not have to worry about the commercial pressures of popularity. A video by Bill Viola, for example, is not tested on audiences to check that they approve of its ending. Hollywood produces stirring, coherent narratives, soaps peddle sentiment and moral lessons, and pop songs tell of love and plaintive rebellion.
In art, by contrast, all narratives are left open, all morals are questioned and all traces of sentiment are expunged. Thus we have Lego concentration camps (Zbigniew Libera), snuff movies (Sergei Bugaev Afrika), offences to decent taste (eating babies and copulating with melons, to take a couple of recent examples) and genetic manipulation for aesthetic purposes (Eduardo Kac and others). In its dark explorations of the human psyche, contemporary art appears to hold out no consolation. But through all the negativity, a seemingly more positive message emerges.
Contemporary art appears to exist in a zone of freedom, set apart from mundane, everyday life, and from its rules and restrictions. The economy and its complementary mass culture function according to strict conventions; contemporary art does the opposite. The idea that capitalism allows space for such free expression could be taken as rather reassuring. The message is that art is a law unto itself, unaffected by the demands of private patrons, religion, business and the state.
Even when works bear a direct relation to mass culture and commerce - for example, when Sylvie Fleury gilds a supermarket trolley or displays the results of her shopping trips to fashion boutiques, or when Guillaume Bijl builds a supermarket inside a gallery - they serve to underline the huge difference between the two realms: the subject is cheap and accessible; the artwork is expensive and rare, further elevated by the grand status of the institution in which it is displayed. And yet, although it is not certain what comments Fleury and Bijl are making in these works, they none the less draw attention to how art is marketed, sold and consumed like everything else.
Indeed, the "otherness" attributed to art masks how the art market is becoming increasingly integrated into the general run of capitalist activity. This is made more visible by increasing pressures on art to be useful. As market forces tear up old attachments and certainties, states turn to art as a balm to foster social calm and cultural solidarity. Corporations, too, bear down on museums, seeking to assure an attachment to their brands that cannot be purchased by direct advertising. As the slogan of the tobacco giant Philip Morris said: "It takes art to make a company great." Because major shows are impossible without corporate support, big business has a significant influence on what gets seen. Corporations generally want art that is accessible (at least at first sight), reproduces well on magazine pages, appeals to the young and wealthy, is newsworthy and connected with celebrities.
Thus there are lots of artists who play at being young (making fun paintings of pop stars, for example), or brand themselves as young, or make work about being young. The most craven merely video celebrities. Many artists try to brand themselves so that their works become no more than self-conscious side effects of their celebrity. Tracey Emin's work, for example, is primarily about herself. Meanwhile, the museums - ever more manifestly the servants of corporations - become brands too, their logos decorating banners, posters and catalogues so that the work on display bears the stamp of their institutional approval. The idea that an exhibition might take an ambivalent or even critical view of its contents now appears merely quaint.
Artists compete to find a distinctive place in this art world. As more and more positions are filled, it seems as if no combination of elements in an artwork is taboo. But in their quest for originality and provocation, artists tirelessly reshuffle the same elements (sharks and vitrines, paint and dung, boats and modernist sculpture, museums and folk culture, and so on). Such combinations in art are closely reflected in advertising - and indeed, the two feed off each other. The series of adverts for Absolut vodka, in which paintings or objects were reproduced as magazine pages, made the relation between artist and corporation particularly transparent.
Thus art's lack of convention has become entirely conventional: beneath its apparently various surfaces there is a hidden uniformity. The novelty of art, its rapid play of images, is merely a pale reflection of the continual evaporation of certainties produced by capital, which tears up all resistance to the unrestricted flow of funds, data, products and people across the globe. Thomas Frank and his collaborators on The Baffler, an American journal of cultural criticism, have tracked the rise of the corporate rhetoric of nonconformity, in which consumers are exhorted to be themselves and break the rules. In its sanctioned realm of freedom, art does much the same. In mixing cultural elements and demolishing old attachments, it acts as an agent of neoliberalism, celebrating as the exercise of freedom all that is forced upon us.
There are ways to protest against the use of art as a servant of business and the state. The most basic is to resist the idea that any combination of elements is as fine as any other, and that all artistic products are an unalloyed good, by attacking the objects in question. The popular delight over the destruction of works by young British artists in a warehouse fire is indicative of such resistance. A more positive response has been to make art of explicit political use - for example, in the service of the anti-capitalist movement. Another, often linked, strategy is to undermine the archaic art market and the monopoly of the museum by making art that can be widely distributed and encourages the active participation of its viewers. Much of this has been taking place online.
Art's main purpose is to assure its educated viewers that, despite the corruption of democracy, the manipulations of the media, the pollution of the mental environment by endless and strident commercial propaganda, they are still undamaged and free, capable of grasping complexity and contradiction. Yet, in its increasingly evident use, this main purpose starts to falter. If, in wandering around galleries, you no longer think about the wonders of art but rather of the principles of sponsorship or the processes of gentrification, then you begin to grasp the limits of art's supposed freedom.
Julian Stallabrass is a senior lecturer at the Courtauld Institute of Art. His new book, Art Incorporated: the story of contemporary art, is published by Oxford University Press (£12.99)