The Holocaust remains a taboo subject, yet this week a filmmaker has regaled Cannes with his black comedy based on the lives of victims of the Nazis. Howard Jacobson asks whether there will ever be a time when comedy can draw the poison out of so many embittered hearts
"IF YOU could lick my heart," said one of the Holocaust survivors in Claude Lanzmann's film, Shoah, "it would poison you."

How long should one give oneself to let that sink in? Forever?

Is there anything thereafter to say? The rest is silence, surely. The silence that drowns out all other sounds.

God's name was once considered too terrible to utter. In our time we drop God's name without thinking twice about it, but woe betide the man who speaks the holy word "Holocaust" in vain. "To write poetry after Auschwitz," Adorno famously remarked, "is barbaric." And that's poetry, the most reverend of all forms of expression. So as for joking about the Holocaust!

But what good is served by taking a poisonous heart into eternity? Memory is served by it, we are told. We must never forget. And as long as our hearts taste like ratsbane we will never forget. Which begs the question of what sort of memory is best for us, best helps us to understand, best helps us to commemorate, and best helps us to live.

In an essay in Geoffrey Hartmann's Holocaust Remembrance: The Shapes of Memory, Saul Friedlander notes the absence, in the Jewish world, of any redeeming myth in the wake of the Holocaust: "... some 50 years after the events, no mythical framework seems to be taking hold of the Jewish imagination, nor does the best of literature and art dealing with the Shoah offer any redemptive stance. In fact the opposite appears to be true."

Of course it's possible that it's still too soon for redemptive myths. The function of a redemptive myth is to turn memory into a necessary form of forgetting. After only 50 years - a mere flea-bite in time - we may not be ready for that cruel but sustaining paradox. Remember in order to forget? Forget in order to remember? Yes, but how could we forget thee?

Through what power, even for the least division of an hour, could we be so beguiled as to be blind to our most grievous loss...?

And if it's too soon for the myths, mustn't it follow that it's certainly too soon for the jokes. In Thurber's formula, "TRAGEDY + TIME = COMEDY". We've had the tragedy; what we haven't had is the time.

False algebra, I think. I don't subscribe to the argument that comedy must always wait its turn, be kept cooling its heels in the ante-room of tragedy, so to speak, at a dignified distance from where the real business of tribulation is taking place; for by shutting comedy out all we do is deprive ourselves of the good comedy can do us.

It's now that we need the transformative beneficence of comedy, not in 500 years, when the Holocaust will have become a sort of allegory anyway.

Behind the outrage that someone has dared to make a comic film on a Holocaust- related subject lies in an understandable objection to levity in a hallowed place. I have no taste for levity myself, in any place. We are dying of lightness. But comedy and levity are by no means the same thing; there is no more reason to assume that a comedy will be light-hearted than that a work in which there is no comedy will be truly serious.

It may be the case for all I know - for no one sent me to Cannes to see it - that Roberto Benigni's My Life Is Beautiful is trivial, footling in the manner of Blackadder or 'Ello 'Ello. In which case that would be the objection - that it is of no consequence, not that it is comic. For my money there was an absence of proper moral weight in Schindler's List. And that certainly wasn't owing to his comic inclinations, since Spielberg has no comic inclinations.

There are some cultures in which it would not be necessary to make this apology for comedy. Outside the Judaeo-Christian tradition - and you can't get more Judaeo-Christian than the Holocaust - the comic and the sacred, let alone the comic and the merely serious, are not taken to be mutually exclusive.

Wherever Jews and Christians are not, clowns perform sacred functions, enjoy holy office, officiate in the breaking of the strictest of taboos, defy every decency owing to the living and the dead, overturn the normal order and appearance of things, thereby revivifying the senses and replenishing hope.

Since comedy has the power to disarrange the visible world and reassemble it - in other words, since comedy can be visionary - it makes no sense to shoo it away from suffering and confine it to the sphere of light entertainment. Its province is pain and trouble. Affliction is where it feeds. Why send an ambulance to a house where nobody is ill? We know more about the way sick jokes and black comedy and gallows humour work than we often care to admit. No matter how bitter or bilious our laughter is, the sound it makes is invariably one of affirmation.

Laughter proclaims life, even in the face of death. Which is sometimes tactless of it. No wonder we fear it. It acknowledges out part in inhuman cruelty, demystifies inhumanity itself, and can even make some terrible self-preservative virtue of it, for no man is an angel only when he laughs.

But then nor is he only a beast, which is where the redemption comes in.

I'm not saying that I'm up to writing a redemptive comedy of the death camps myself, or that I know what one would look like, or that Benigni's film fits the bill. Only that we shouldn't, before the event, close down the very act of imagination which may be capable of removing the poison from our hearts.

Howard Jacobson's novel `No More Mister Nice Guy' has just been published by Jonathan Cape.