Dr Rowan Williams is expected to use his Christmas sermon to condemn the "aggressive secularism" of the French government. President Chirac wants to ban the wearing of all overt religious symbols in state schools, including the Muslim hijab, the Jewish skullcap and ostentatious Christian crosses. Secularism is certainly one of the chief legacies of the Revolution, and it has often been aggressive. But its achievements include granting full civic rights to Jews for the first time, and restoring them to Protestants. It is a proud inheritance - and not obviously inferior to the "undogmatic", piecemeal way in which our own religious minorities were eventually emancipated. But have the French got it wrong this time?
I have no dislike for notions of female modesty that are current in the Muslim world - quite the contrary. During a recent visit to Iran I was struck by how the demureness that is universal went with accepted rules of flirtation that we have forgotten in the West, and how from within the inviolable security of the chador Persian women seemed beguilingly well-versed in them. They are also very bold in their eye language. After a few weeks exposure to this, it is easy to find the naive blatancy of many young Western women a bit depressing.
What was not beguiling, of course, is that the demureness is state-imposed, and many of the women I talked to hated it. It is still possible for women who flout the rules too blatantly to get roughed up by the basijis - the street enforcers of the regime.
Dress is a religious and political issue, not only in Iran but through much of the Arab Middle East. During the revolution that brought down the Shah, hundreds of thousands of women militantly adopted the chador in passionate opposition to his secular regime.
Dress is just as sensitive in Egypt. When the President's wife was interviewed on television by two women, one wore the hijab, the other was scarveless. This is normal procedure - the secular government's way of trying to defuse the issue by insinuating that it is just a matter of taste.
The same is true in Syria, where the secular regime is under increasing pressure from Islamists. I had a conversation with the Syrian Orthodox Archbishop of Aleppo. He said:
"Fundamentalism is growing in the hearts of the people. Take the hijab. A few years ago only 10 per cent of Muslim women wore it. Now at least 80 per cent wear it. All this is a form of self-protection. You wear the hijab, chador and you feel protected, part of this vast ocean of like-minded people. You may be part of the marginalised poor - but you can see yourself among others on the streets and think: 'Our numbers are legion.' "
Although modesty is enjoined in the Koran, there is no specific rule about covering the head. The main text enjoins women in public to "lower their gaze... and draw their veils over their bosoms". But now that the hijab has become a badge of pride and a symbol of solidarity, the social pressure to wear it is immense.
We do not have the French secularist tradition, so any unease we may feel at the spread here of overt religious symbols can easily look like mere hostility to the Other. But a downside of muticulturalism is that in minority communities customs become fossilised. People fetishise their badges of pride as if they were essential. I am half Italian, and was partly brought up among an Italian community - but our sense of Italianness did not get much beyond eating pasta, being proud of the Pope (always, then, an Italian) and turning up en masse to hear Gigli when he came to sing in the local concert hall.
Neither the hijab nor the Jewish skullcap are enjoined by religion. The latter became common after the Six Day War - again as a badge of solidarity. (I can pinpoint this exactly, because I remember the present Chief Rabbi, then an undergraduate in my Cambridge College, returning for the autumn term that year transformed with newly acquired beard and skullcap.) Obviously there is nothing wrong with these symbols; but once you treat them as essential, you distort the religion.
Dr Rowan Williams is entirely right in wanting to combat hostility to Islam - that ugliest of the new hatreds. But the greatest problem in modern Islam is that there has been no intellectual and cultural revival to accompany the religious resurgence. Historically Islam has been brilliant in absorbing other cultures. In its greatest period it assimilated and transmitted Greek philosophy and science and virtually created Mediterranean agriculture and cuisine as we now know it.
In modern times the strongest leaders of Muslim states - Mehmet Ali in Egypt, Kemal Ataturk in Turkey - were determined to open their countries to the West. But there has also been the opposite tradition of retreat into fortress Islam, and this tradition, with its rejection of modernity, now commands the loudest voices.
We need not imitate the French. But we can still hope, not so much for a "moderate" Islam - a vacuous concept - but for an Islam that resumes its old traditions of appropriating modernity. Modernity, for the time being, lies in the West. To assume that the only way to obey the religious rules of modesty is to cling to an oriental style of dress is simple-minded.