There are between 44 and 56 million Muslims in Europe. About 19 million, or 3.7%, live in the 27 countries of the European Union, which has an overall population of over 503 million. A mere 2.5 million Muslims live in the United States, much the same as in the UK. These numbers are not in themselves a problem, but when incomers fail or refuse to integrate, friction and divisions split the society. In my youth in Northern Ireland, it was unthinkable for a Catholic to marry a Protestant or vice versa. Today, only about 10% of marriages are mixed. There is still a long way to go, but the ban on mixed marriages, like the insistence on separate schooling (which continues), contributed to a fragmented society that erupted in violence in 1968 and through the long years of "the Troubles" that followed.
Separate Muslim schools, or bans on Muslim girls attending ballet schools or playing music or, for boys, playing cricket are not, of course, a disaster for Western civilization. But when Muslims denounce democracy, or preach the corruption and hatefulness of Jews and Christians, and alleging that rabbis and priests have distorted the words of the Torah and the Gospels — a doctrine known as tahrif [Qur'an 4:46] -- this hardly advances integration.
While we may be hoping that if Muslims are exposed to our way of life, they will prefer it, they may be hoping that if we are exposed to their way of life, we will prefer it. When extremist Muslims tell us we are not wanted in their lives or that they do not want to share our lives, or when they plant bombs in London, New York, Boston or Madrid, this antagonism to the West, and the constant stoking of resentment, becomes seriously corrosive.
Extremists are not "sui generis." Many take their inspiration from a body of Islamic literature that extols Muslims above the rest of mankind. Many emerge from that literature and from the concept of al-wala' wa'l-bara' ("loyalty and enmity"), from years spent in Muslim-only schools, from segregated meetings at university, or from anti-Israel speeches or marches.
The harm we experience from this drive to separatism is considerable, but it is not, I think, as great as the harm often done to Muslims themselves. Northern Irish Protestants and Catholics alike paid a heavy price for their decades of aloofness from one another's lives -- a price that has not yet been paid in full. When a boy is told it is good to kill in the cause of Allah, but that he may not play chess because it is worse than playing dice — and playing dice is like dipping your hands in pig's blood — ("How could the Lawgiver [Muhammad]), forbid dice but permit chess, which is many times worse?"), will he not grow up with a fragmentary sense of what is evil and what is good? Or perhaps the conviction that whatever is outside Sharia law is evil and whatever is inside Sharia law is good? The more Muslim schools there are to pass on such views to children, the more adults there are likely to be who might hope to gain the benefits but evade the responsibilities of life in modern Western culture. From these adults, though possibly small in number, extremists tend to emerge.
The "Muslim patrols" that try to take over a borough of London and impose Shari'a law on non-Muslims give many Westerners the sense that we are not wanted in our own countries, that we are the inferiors of a minority whose achievements are less than impressive, that we must abandon our truest principles about individual liberty and democracy and shed our morality because another group thinks it has a monopoly on what is right and wrong.
In Western countries, free speech permits a wide range of opinions; these are what distinguish us from cultures that are committed to control and that often seem to use religion to advance political aims.
Although none of us has a monopoly on what is right and wrong, when I lived in Iran, I learned how to speak, gesture, and dress to fit in. When I lived in Morocco, I wore a jellaba and tried to improve my Moroccan Arabic. Conversely, when incomers defy the norms of their host culture, it can, and perhaps should, create a sense of unease.
Western societies have been working for decades on legislation to raise the status of women in our homes and workplaces. Perhaps we feel uncomfortable with the hijab because we suspect — rightly or wrongly — that rather than reflecting a protection of women, as is heralded, at another level it reflects an oppression of women that many wish would become outdated.
There may be a suspicion that in many Muslim countries women wear a veil not out of their own free choice, but as the result of coercion, from either members of the family or pressures of the community. In Saudi Arabia and Iran, for example, a young woman with a scarf slightly awry may be stopped by patrols in the street, accused of being bad-hijab, then publicly humiliated, and possibly taken to a police station and jailed.
If Muslims come to our shores or are born and brought up here, they have the same freedoms, responsibilities, and the rights we all possess. Here in Britain, Muslims like all other citizens, have free access to our health services, free access to public schooling to the age of 18, a right to vote or to be elected as local councillors and national MPs, a right to own businesses, and freedom to serve as lifeboat sailors or magistrates or special constables.
The doctrine of al-wala' wa'l-bara', however, works against all this. In its most extreme form, it reflects the view of Ahmad Sirhindi that, "Whenever a Jew is killed, it is for the benefit of Islam."
We do not mind people demonstrating in front of parliament calling for changes to the law. But when the banners read, "Behead those who insult Islam" or "Britain, your 9/11 is on its way," it is probably advisable to reassess matters.
No doubt Muslims have things to teach us, but those things cannot be the right to abuse women, homosexuals, people who are not Muslim, or the right to murder someone for apostasy. Our societies are better without those acts. Some Muslims may want to restrict the lives of women, the same way that, for example, in India (before the British put a stop to it), women were forced to commit suttee -- be thrown on the burning funeral pyre after their husbands had died. But should we actually be encouraging such behaviour?
Whenever incoming groups make efforts to integrate, there are immense benefits to them -- economically, in human rights, engagement in politics and so on. When we make honor killings or female genital mutilation or underage marriage illegal, surely that prohibition brings immense benefits to Muslim women and children, the same way outlawing suttee did.
Revisions or interpretations such as these, however, are what al-wala' wa'l-bara' seems designed to prevent.
Like Muslims, we have to struggle with our prejudices and a tendency to stereotype others. In the end, this attitude becomes a standoff. A 2006 Pew survey stated that, "in Britain worries about Islamic extremism are intense among both the general public and the Muslim minority population as well. Concerns about the problem rose markedly this year among the general public. And worries about extremism within the British Muslim community are greater than in France, Germany, and Spain."
Similar concerns, even if not as high as in Britain, exist across Europe. Incidents such as the 2013 public beheading of soldier Lee Rigby have horrified most of the public. Britons have been particularly estranged by the Muslim protests that took place in Barking in 2010, notably when 40 demonstrators screamed abuse and carried defamatory placards that insulted British soldiers returning from Afghanistan and by plans for a protest in Wootton Basset, where the coffins of dead British soldiers were processed along the main street while large numbers of their friends and families stood in silence to honour their passing.
British Muslims, many waving the black flag of jihad, hurl insults and abuse at soldiers returning from Afghanistan in 2010, in London.
When Muslims send their young girls abroad to have their private parts mutilated (the first prosecutions for this have just started in the UK), or bring them to Pakistan on holidays -- when thirteen-year-olds are forcibly married to cousins, and we do nothing -- we betray values on which our grandparents would probably have instinctively acted, again, as they did against suttee.
Preachers in British mosques are still calling for jihad against their fellow citizens, and Islamists march with others through the streets of Antwerp, chanting, "Hamas, Hamas, Jews to the gas." Honor killings and domestic violence take place, and the Muslim -- and even European communities -- close their ranks and no one is prosecuted, or even criticized.
Are we actually seeing -- with the quiet acceptance of such atrocities -- a passive urge to self-destruction infiltrate the heart of our society? Did our parents really fight the Nazis to see Britain, France or the U.S. give way to another totalitarian ideology?
Western society gives great scope to minority views, but we do not cut our girl children with razor blades, even to spare them a possibly lethal butchery with unwashed cut-glass elsewhere; and we do not marry them off at puberty.
As a multiculturalist, I enjoy what other countries have to offer. We should all read the poetry of Hafez, visit the Baha'i gardens in Haifa and eat Chinese food with chopsticks twice a day. If all change were forbidden, there would never be progress. Our ability to change is what distances us so much from Islam, where kull al-bid'a kufr -- "every innovation is unbelief" -- in many places still holds sway.
And this is where the issue of Islam is crucial. From its beginning, for centuries, Muslims conquered, enslaved, and reduced Jews and Christians to dhimmitude [the state of "tolerated" lower-class citizens who have to pay protection money]. They also tightly controlled what other Muslims could think.
Islam has not changed much internally, but it has already changed the world. The disappearance of communism as the principal enemy of Western democracy left a gap into which Islamic forces, some open, some clandestine, are moving -- all apparently with a profound suspicion of the West and its motives.
Our politicians, lawyers and intellectuals do not, for the most part, appear to believe there is a threat. They also appear not much to care if our values are undermined and, in their place, a strong version of Islam is installed in the heart of the only civilization that has given mankind freedom, tolerance, and the democratic right to master our own affairs.
There are great things in Islam and there is much we can and must learn from its history and culture. But the religion itself — not the Safavid and Mughal miniatures, not the ringing of the santurs, not the exquisite minarets and domes — remains impervious to the temptations and freedoms we can offer.
Let us go on sitting at cafés in Paris, watching languid and beautiful women glide by, and remember their sisters, married to men who beat them and whom religious law will not let them divorce, while sometimes sharing their husbands with one, two or three other wives, and sitting at home while their husbands go out to contract yet another temporary or misyar marriage. There are two directions we can take. It is up to our politicians and our religious leaders to choose which way we go.
 The Persian word bad is an exact equivalent of the English word, but is not borrowed from English.
 Excerpted from Saiyid Athar Abbas Rizvi, Muslim Revivalist Movements in Northern India in the Sixteenth and Seventeenth Centuries (Agra, Lucknow: Agra University, Balkrishna Book Co., 1965), pp.247-50; and Yohanan Friedmann, Shaykh Ahmad Sirhindi: An Outline of His Thought and a Study of His Image in the Eyes of Posterity (Montreal, Quebec: McGill University, Institute of Islamic Studies, 1971), pp. 73-74.
 That's not entirely true. The British embassy in Islamabad does have a special unit that responds to news of a British girl who has been forcibly married, finds her and rescues her.