The critic, the artist's wife and the unanswerable accusation

Critics have killed from time to time; perhaps they have. They have killed off careers, certainly, ruined hopes and broken hearts, and people may die of such things. But these crimes never come to trial. They hardly could. Giving grief is no murder, and even at the level of "moral responsibility" the matter is elusive. The chain of cause and consequence is lost in hypotheses. If x had not written that, if y had not been in that state of mind or body...

It's very true that critics, like other writers, hardly imagine the consequences of their words, or that their words might have consequences. Notices are written and sent into the world without a thought that there is at least one person who will read them as carefully as a love letter, drawing from each phrase every nuance of encouragement or destruction. As for intent, the most damning and virulent critics may still say that it's nothing personal; their object is not the artist as such, but the public or the culture. Criticism operates in an ethical limbo. But Byron said the reviews killed John Keats, and RB Kitaj says they killed his wife.

The RA Summer Exhibition opens tomorrow, and in the first room Kitaj has a picture: The Critic Kills. It's what a critic might call a departure. It resembles a conceptual, text-based painting that might have been done by someone - not Kitaj - in the 1970s. The picture presents a photograph of the painter Sandra Fisher, Kitaj's late wife. There is a piece of hand- written paper, headed "Instruction", and starting "This painting is a magazine. It is the first issue of an irregular art journal called Sandra." There is a printed quotation from Hitler: "Works of art that are not capable of being understood in themselves, but require some pretentious instruction book to justify their existence will never again find their way to the German People." There is a blood-stained slogan: THE CRITIC KILLS. The picture is signed "by Ron and Sandra".

The subject of the picture - or its occasion, but they are indistinguishable - is that, in 1994, Kitaj had a retrospective at the Tate Gallery. It opened in June to mainly hostile and fiercely personal views, which attacked Kitaj on every front. The critics were especially piqued by Kitaj's decision to put up his own notes ("instruction books") as captions by the paintings, which offered interpretations and biographical background and sometimes referred to the work of great dead artists. This was taken as the height of vainglory and pretension: as much as his artistic achievement, it was felt, Kitaj himself needed a severe drubbing, and he got that. In September Sandra Fisher died, aged 47, following a stroke. Kitaj said later: "They wounded me. They tried to kill me. They got her instead." And now, again, in The Critic Kills.

Art sometimes aspires to ethical limbo, too: a realm for the imagination to have free-play, which may reflect but never touch the world. Remember - as they say - this is not a tract, it is a work of art, it is a fiction. But in The Critic Kills, this distinction breaks down entirely. The picture makes a direct and specific allegation about events in the world, which can't be bracketed as fiction or personal mythology. What is stated is unignorably in earnest: that the critics attacked Kitaj and his work: that in so doing they caused Sandra Fisher's death. And in the bluntness of its devices, the picture hardly gives this statement any artistic inflection, save for the bitter and ironic juxtaposition of its texts.

But here a short circuit occurs. The allegation, though publicly made, is provided with no public substantiation. The connection is drawn, the charge is stated, but no reason is given for thinking it true, and perhaps no reason could be given, apart from personal conviction. So one can only turn from the picture to the grief and rage behind it - things that defy public response. That surely is the intention: that the piece should be unassailable either as art or as argument, allowing no response on any terms, that it should stand as a blank, inarticulable, unanswerable reproach.

Or maybe it does permit an answer. If one or more of the critics concerned were now to acknowledge their responsibility, and to end their own lives... And who would be responsible for that?

A barely conceivable consequence - yet these consequences are always barely conceivable until they happen, and always tenuous when they do. Nor is it only critics whose actions may prove fatal; artists too. "Did that play of mine send out / Certain men the English shot?", Yeats wondered in a poem. And, some years ago, David Hare imagined a "cautionary tale for playwrights - that you will whip yourself up into a fine frenzy of dramatic writing on stage, have your superbly played heroine step harrowingly to the front of the stage and cry out in despair, `It is better that we had never been born' - and there will be an answering shot from the back of the stalls, and one of the customers will slump down dead."

It is a cautionary tale for everyone who writes or does anything publicly - but you cannot say what precautions it recommends. Any message to the world may prove a matter of life and death. Critics can "kill" artists. Artists can "kill" audiences. To memorialise these oblique and doubtful fatalities is no bad thing either.

Tom Sutcliffe returns next week