The Guillotine: Twentieth-Century Classics That Won't Last - No 28: Robert Mapplethorpe

By definition, a photographer's relationship to the objective world is less "mediated" than that of any other species of artist. It is, for the non-initiate, a question of the pecking order of by and about. Thus The Ground Beneath Her Feet is a novel by Salman Rushdie about Orpheus and Eurydice; Eyes Wide Shut is a film by Stanley Kubrick about marital tensions in contemporary Manhattan; on the other hand, a snapshot of Diana is primarily about her and only secondarily by Lord Lichfield. Diana herself is what we see, not the Lichfield touch.

At first glance, Robert Mapplethorpe would appear to be an exception to the rule in that, even if his work includes celebrity portraiture - Andy Warhol, Patti Smith - he is best-known for his photographs of mostly anonymous sitters. Since his alone is the household name, and since the eclat of his talent is indisputable, surely he has been guaranteed everlasting tenure in posterity?

If it isn't as simple as that, it's because of the nature of his subject- matter. In a word, sex. Like some privileged creditor, sex always takes precedence. A naked penis by Lucian Freud is still primarily (just about) one element in a painting by Lucian Freud; when photographed, by even as brilliant a practitioner as Mapplethorpe, it abruptly reasserts its objective identity as a naked penis. It, rather than the quality of Mapplethorpe's "vision", is what our eyes are drawn to, and it would be absurd to pretend otherwise.

That fact, in itself, need not constitute an obstacle to posthumous fame. But what, for many, is shocking in Mapplethorpe's work is less the nudity as such than the unjudgmental depiction of violent sado-masochistic acts, invariably between males. Shocking, though, for how much longer? When one recalls that, at the turn of the last century, a glimpse of a well- turned ankle, as they used to say, was enough to provoke a sexual frisson, and when one then considers how far along that road we've already travelled, logic dictates that, as the new century unfolds, representations of sex will become graphic to a degree that we cannot currently imagine.

Heaven knows where it will all end - but, wherever it does, it's certain that even the raunchiest of Mapplethorpe's photographs are going to look unutterably tame by comparison.