Twenty years ago this Friday Salman Rushdie published The Satanic Verses. Four years in the making and supported by a then almost unheard of advance of $850,000 from his publishers Penguin, Rushdie had hoped the novel would cement his reputation as the most important British novelist of his generation. The book certainly set the world alight - though not quite in the way it was meant to.
The Satanic Verses was, Rushdie said in an interview before publication, a novel about 'migration, metamorphosis, divided selves, love, death'. It was also a satire on Islam, 'a serious attempt', in his words, 'to write about religion and revelation from the point of view of a secular person'. For some that was unacceptable, turning the novel, in the words of the British Muslim philosopher Shabbir Akhtar, into a piece of 'hate literature'.
Within a month The Satanic Verses had been banned in Rushdie's native India, after protests from Islamic radicals. By the end of the year, protestors had burnt a copy of the novel on the streets of Bolton, in northern England. And then on 14 February 1989 came the event that transformed the Rushdie affair - Iran's spiritual leader, the Ayatollah Khomeini, issued his fatwa. 'I inform all zealous Muslims of the world', he proclaimed, 'that the author of the book entitled The Satanic Verses - which has been compiled, printed and published in opposition to Islam, the Prophet and the Qur'an - and all those involved in its publication who were aware of its contents are sentenced to death.'
Thanks to the fatwa, the Rushdie affair became the most important free speech controversy of modern times. It also became a watershed in our attitudes to freedom of expression. Rushdie's critics lost the battle - The Satanic Verses continues to be published. But they won the war. The argument at the heart of the anti-Rushdie case - that it is morally unacceptable to cause offence to other cultures - is now widely accepted.
In 1989 even a fatwa could not stop the continued publication of The Satanic Verses. Salman Rushdie was forced into hiding for almost a decade. Translators and publishers were killed, bookshops bombed and Penguin staff forced to wear bomb-proof vests. Yet Penguin never wavered in its commitment to Rushdie's novel.
Today, all it takes for a publisher to run for cover is a letter from an outraged academic. In September, the American publishers Random House torpedoed the publication of a novel that it had bought for $100,000 for fear of setting off another Rushdie affair. Written by the journalist Sherry Jones, The Jewel of Medina is a racy, historical novel about Aisha, Muhammad's youngest wife. Random House had sent galley proofs to writers and scholars, hoping for endorsements. One of those on the list, Denise Spellberg, an associate professor of Islamic History at University of Texas, condemned the book as 'offensive'. Random House immediately pulled the book.
In the 20 years between the publication of The Satanic Verses and the withdrawal of The Jewel of Medina, the fatwa has in effect become internalised. Not only do publishers drop books deemed offensive, but theatres savage plays, opera houses cut productions, art galleries censor shows, all in the name of cultural sensitivity.
'You would think twice, if you were honest', said Ramin Gray, the Associate Director at London's Royal Court Theatre, when asked he would put on a play critical of Islam. 'You'd have to take the play on its individual merits, but given the time we're in, it's very hard, because you'd worry that if you cause offence then the whole enterprise would become buried in a sea of controversy. It does make you tread carefully.' Last June, the theatre cancelled a new adaptation of Aristophanes' Lysistrata, set in Muslim heaven, for fear of causing offence. Another London theatre, the Barbican, carved chunks out of its production of Tamburlaine the Great for the same reason, while Berlin's Deutsche Oper cancelled a production of Mozart's Idomeneo in 2006 because of its depiction of Mohammed.
In the past, free speech was seen as an inherent good, the fullest extension of which was a necessary condition for the elucidation of truth, the expression of moral autonomy, the maintenance of social progress and the development of other liberties. Restrictions on free speech were viewed as the exception rather than the norm, to be wielded carefully, and only in those cases where speech might cause direct harm.
In the post-Rushdie world speech has come to be seen not intrinsically as a good, but inherently as a problem, because it can offend as well as harm, and speech that offends can be as socially damaging as speech that harms. Speech, therefore, has to be restrained by custom, especially in a diverse society, with a variety of deeply held views and beliefs, and censorship (and self-censorship) has to become the norm. 'Self-censorship', Shabbir Akhtar has suggested, 'is a meaningful demand in a world of varied and passionately held convictions. What Rushdie publishes about Islam is not just his business. It is everyone's - not least every Muslim's - business.' In other words, if I don't like what you say, you can't say it.
Increasingly Western liberals have come to agree. And where self-censorship is deemed insufficient there is now a battery of laws to enforce state censorship - from legislation against 'hate speech' to the demand by the United Nations that every member take a stand against the 'defamation of religion'. It is not just critics of Islam who are being silenced. British laws against the 'glorification of terrorism', and moves in America to amend the First Amendment so that it no longer provides protection for Islamic radicals, show that Islamic critics, too, can no longer say the unsayable.
Twenty years on from The Satanic Verses it is time we took a stand against this trend. 'Give me the liberty to know, to utter, and to argue freely according to conscience, above all liberties', wrote the seventeenth century poet John Milton, adding that 'He who destroys a good book destroys reason itself'. Freedom of expression is not just an important liberty, it is the very foundation of liberty, for without such freedom we cannot define what liberties are.
Shabbir Akhtar was right: what Rushdie, or anyone else, says is everybody's business. It is everybody's business to ensure that no one is deprived of their right to say what they wish, even if what they say is seen by some as offensive. As George Orwell once put it, 'If liberty means anything, it means the right to tell people what they do not want to hear'.