Johann Hari: Rowan Williams has shown us one thing – why multiculturalism must be abandoned

For five days now, the Archbishop of Canterbury has been chorusing: how do you solve a problem like Sharia? Ever since he suggested it is "unavoidable" – and desirable – for Britain to have Islamic courts ruling on Muslim family affairs, bashing the bishop has become a national sport. But this row shouldn't be just about the pitiful contortions of the head of a dying Church. Rowan Williams has shown us why the doctrine of multiculturalism needs to abandoned.

If you really believe that Britain is comprised of a smorgasbord of "cultures" that need to be preserved, promoted and respected as an end in itself, then this proposal is perfectly logical. Different cultures should have different courts, and rules, and schools.

We don't need to speculate about what these British sharia courts would look like. They already exist in some mosques across Britain, as voluntary enterprises. Last month, a plain, unsensationalist documentary called Divorce: Sharia Style looked at the judgements they hand down.

If a man wants a divorce, he simply has to say to his wife, "I divorce you" three times over three months. The wife has no right of appeal, and no right to ask for a reason. If a woman wants a divorce, by contrast, she has to humbly ask her husband. If he refuses, she must turn to a sharia court, and convince three Mullahs that her husband has behaved "unreasonably" – according to the rules laid out in a pre-modern text that recommends domestic violence if your wife gets uppity.

Irum Shazad, a 26-year-old British woman, travels from her battered women's refuge to a sharia court in East London. She explains that her husband was so abusive she slashed her wrists with a carving knife. The court tells her this was a sin, making her as bad as him. They tell her to go back to her husband. (They grant a divorce half a year later, after a dozen more "last chances" for him to abuse her.)

Then we meet Nasirin Iqbal, a 27-year-old Pakistani woman who was shipped to Britain five years ago to marry. Her husband, Imran, has kept her isolated, and she does not speak a word of English. "I came here thinking he'd treat me well," she says. "But he keeps hurting me. He brought me here to use me. I'm not an object.... Do I not have a heart?... He tells me I'm stuck with him, and under Islam he can treat me however he wants. 'I am a man, I can treat you how I want'."

We see how Imran torments her, announcing, "You are a reject. I didn't want to marry you." He takes a second wife in Pakistan, and texts her all day in front of Nasirin declaring his love. The sharia court issues a fatwa saying the marriage stands. She doesn't seem to know this isn't a court of law. "I can't ignore what they say," she cries. "You have to go with what they say."

These are the courts that Rowan Williams would give the stamp of British law. In his lecture, he worries that this could harm women – before serving up a theological gloop, saying that sharia could be reinterpreted in a way compatible with the rights of women. But if that happens, why would you need different courts? What would be the point?

The argument that women will only have to enter these courts if they freely choose to shows a near-total disconnection from the reality of Muslim women's lives. Most of the women who will be drawn into "consenting" are, like Nasirin, recent immigrants with little idea of their legal options. Then there are the threats of excommunication – or violence – from some families. As the Muslim feminist Irshad Manji puts it: "When it comes to contemporary sharia, choice is theory; intimidation is the reality."

These courts highlight in their purest form the problem with multiculturalism. It has become a feel-good doctrine mindlessly celebrating "difference", without looking at what that difference actually means.

Yet many people feel instinctively uncomfortable when we talk about ditching multiculturalism – for a good reason. The only alternative they are aware of is the old whiter-than-white monoculturalism. This view, voiced most clearly by Enoch Powell and Norman Tebbit, believes that if people are going to live together, they need to look and feel similar, and have a tightly prescribed shared identity. They argue that the number of newcomers should be small, and need to be pressured to assimilate to the 1950s norm of a suburban white family, fast.

Multiculturalism was formed with good intentions as a counter-reaction. But it has become a mirror-image of this old racism, treating Muslim women – and others – as so different that they do not deserve the same rights as the rest of us. As the European-Iranian feminist Azar Majedi puts it: "By creating different laws and judicial systems for each ethnic group, we are not fighting racism. In fact, we are institutionalising it."

When people talk about defending Muslim culture, ask them – which culture? The culture of Irum and Nasireen, or the culture of their abusive husbands? Multiculturalism patronisingly treats immigrants as homogenous blocks – when in fact they are as diffuse and dissenting as the rest of us. Would anybody lump me in with Richard Littlejohn and Nick Griffin as part of a "white community"?

There is a better way for the state to understand and regulate human differences, beyond the old oppositions of Tebbittry and multiculturalism. It is called liberalism. A liberal society allows an individual to do whatever he or she wants, provided it doesn't harm other people. You can choose to wear PVC hotpants or a veil. You can choose to spend all day praying, or all day mocking people who pray.

Where a multiculturalist prizes the rights of religious groups, a liberal favours the rights of the individual. So if you want to preach that the Archangel Gabriel revealed the word of God to an illiterate nomad two millennia ago, you can do it as much as you like. You can write books and hold rallies and make your case. What you cannot do is argue that since this angel supposedly said women are worth half of a man when it comes to inheritance, and that gay people should be killed, you can ditch the rules of liberalism and act on it.

The job of a liberal state is not to stamp The True National Essence on its citizens, nor to promote "difference" for its own sake. It is to uphold the equal rights of every individual – whether they are white men or Muslim women. It has one liberal culture, with freedoms used differently by different people.

So as well as scorning the Archbishop, we should thank him. He has helped to deliver the funeral rites for multiculturalism. With his matted beard and tortured hand-wringing to a desert-God, the Archbishop has unwittingly pointed us towards a vision of a better Britain – one that chooses proudly to be liberal.

j.hari@independent.co.uk