What is Islam - this disturbing, radical excess that represents the East to the West, and the West to the East? Let me begin with the relationship of Islam to Judaism and Christianity, the two other religions of the book.

As the religion of genealogy, of the succession of generations, Judaism is the patriarchal religion par excellence. In Christianity, when the Son dies on the cross, the Father also dies (as Hegel maintained) - which is to say, the patriarchal order as such dies. Hence, the advent of the Holy Spirit introduces a post-paternal/familial community.

In contrast to both Judaism and Christianity, Islam excludes God from the domain of the patriarchal logic. Allah is not a father, not even a symbolic one. Rather, God is one - he is neither born nor does he give birth to creatures.

This is why there is no place for a Holy Family in Islam. This is why Islam so emphasizes the fact that Muhammad himself was an orphan. This is why, in Islam, God intervenes precisely at the moments of the suspension or failure of the paternal function (when the mother or the child are abandoned by the biological father). This is also why Islam represented such a problem for Freud: his entire theory of religion is based on the connection between God and "the father."

But even more importantly, it is this that inscribes politics into the very heart of Islam, since the "genealogical desert" makes it impossible to ground a community in the structures of parenthood or other blood-ties. As Fethi Benslama puts it, "the desert between God and Father is the place where the political institutes itself."

In Islam, it is no longer possible to ground a community in the mode of Totem and Taboo, through the murder of the father and the ensuing guilt which brings brothers together - hence Islam's unexpected actuality. This problem is at the heart of the Muslim "community of believers" - the Umma - and accounts for the overlapping of the religious and the political (the community should be grounded directly in God's word), as well as for the fact that Islam is at its best when it grounds the formation of a community "out of nowhere," in the genealogical desert, as a kind of egalitarian revolutionary fraternity. No wonder, then, that Islam is so appealing to young men who find themselves deprived of family and social networks.

As Moustapha Safouan has argued, it is this "orphanic" character of Islam that accounts for its lack of inherent institutionalization:

"The distinctive mark of Islam is that it is a religion which did not institutionalize itself; it did not , like Christianity, equip itself with a Church. The Islamic Church is in fact the Islamic State: it is the state which invented the so called 'highest religious authority' and it is the head of state who appoints the man to occupy that office; it is the state that builds the great mosques, that supervises religious education; it is the state again that creates the universities, exercises censorship in all the fields of culture, and considers itself as the guardian of morality."

Here we can see how the best and the worst are combined in Islam. It is precisely because Islam lacks an inherent principle of institutionalization that it has proven so vulnerable to being co-opted by state power. Therein resides the choice that confronts Islam: direct "politicization" is inscribed into its very nature, and this overlapping of the religious and the political can either be achieved in the guise of the statist co-option, or in the guise of anti-statist collectives.

But let me now move to a further key distinction between Judaism (along with its Christian continuation) and Islam. As is apparent from the account of Abraham's two sons, Judaism chooses Abraham as the symbolic father; Islam, on the contrary, opts for the lineage of Hagar, for Abraham as the biological father, thereby maintaining the distance between "the father" and God, and retaining God in the domain of the un-symbolisable.

It is nonetheless significant that both Judaism and Islam repress their founding gestures. According to Freud's hypothesis, repression in Judaism stems from the fact that Abraham was not a Jew at all, but an Egyptian - it is thus the founding paternal figure, the one who brings revelation and establishes the covenant with God, that has to come from the outside.

In Islam, however, the repression concerns a woman - Hagar, the Egyptian slave who bore Abraham his first son. For although Abraham and Ishmael (the progenitor of all Arabs, according to the myth) are mentioned dozens of times in Qur'an, Hagar is entirely absent, erased from the official history. As such, she continues to haunt Islam, her traces surviving in rituals, like the obligation of the pilgrims to Mecca to run six times between the two hills Safa and Marwah - a kind of neurotic re-enactment of Hagar's desperate search for water for her son in the desert.

But along with Hagar, there is in the pre-history of Islam the story of Khadija, the first wife of Muhammad himself, who enabled him to differentiate between truth and falsehood, between angelic messages and those from demons.

Mohammad was, of course, the first to doubt the divine origin of his visions, dismissing them as hallucinations, as signs of madness or as outright instances of demonic possession. His first revelation occurred during his Ramadhaan retreat outside Mecca, when the archangel Gabriel appeared to him, calling upon him to "Recite!" (Qara', whence Qur'an).

Mohammad believed he was going mad, and not wishing to spend the rest of his life as Mecca's village idiot, he decided to throw himself from a high rock. But then the vision repeated itself: he heard a voice saying: "O Mohammad! Thou art the apostle of God and I am Gabriel." But even this voice did not reassure him; he returned to his house and, in deep despair, asked Khadija: "Wrap me in a blanket, wrap me up in a blanket." Muhammad told her what had happened to him, and Khadija dutifully gave him comfort.

When, in the course of subsequent visions, Mohammad's doubts persisted, Khadija asked him to tell her when his visitor returned so that they could verify whether it really was Gabriel or a demon. So, when the angel Gabriel next came to Mohammad, Khadija instructed him, "Get up and sit by my left thigh." Mohammad did so, and she said, "Can you see him?" "Yes," he replied. "Now turn round and sit on my right thigh." He did so, and she said, "Can you see him?" When he said that he could, Khadija finally she asked him to move and sit in her lap. After casting aside her veil, she asked, "Can you see him?" And he replied, "No." She then comforted him: "Rejoice and be of good heart, he is an angel and not a Satan."

(There is a further version of this story according to which, in the final test, Khadija not only revealed herself, but made Mohammad "come inside her shift" - that is, penetrate her sexually - and thereupon Gabriel departed. She then said, "This verily is an angel and not a Satan." The underlying assumption is that, while a lustful demon would have enjoyed the sight of copulation, an angel would politely withdraw from the scene.)

Only after Khadija provided him with this proof of the authenticity of his visions was Mohammad cured of his doubts and so could embrace his vocation as God's prophet. The first Muslim, in other words, was Khadija, a woman. She represents what Jacques Lacan called the "big Other," the guarantee of Truth of the subject's enunciation, and it is only in the guise of this circular support - through someone who believes in Muhammad himself - that he can believe in his own message and thus be the messenger of Truth. This is yet a further demonstration of my fundamental contention that belief is never direct: in order for me to believe, somebody else has to believe in me, and what I believe in is this other's belief (in me).

This should be emphasised: a woman possesses a knowledge about the Truth which precedes even the Prophet's knowledge. What further complicates the scenario is the precise mode of Khadija's intervention, the way she was able to draw the line between truth and falsehood, between divine revelation and demonic possession: by putting forward (interposing) herself, her disclosed body, as the untruth embodied.

This is how Khadija's demonstration of truth is achieved through her provocative "monstration" (disclosure), to use Fethi Benslama's term. One thus cannot simply oppose the "good" Islam (reverence of women) and the "bad" Islam (veiled oppressed women). And the point is not simply to return to the "repressed feminist origins" of Islam, to renovate Islam in its feminist aspect: these oppressed origins are simultaneously the very origins of the oppression of women. Oppression does not just oppress the origins; oppression has to oppress its own origins.

The key element of the genealogy of Islam is this passage from the woman as the only one who can verify Truth, to the woman who by her nature lacks reason and faith, cheats and lies, provokes men, interposing herself between them and God as a disturbing presence, and who therefore has to be rendered invisible. Woman, in other words, as an ontological scandal, whose public exposure is an affront to God.

It is interesting, against this background, to examine measures like France's prohibition of Muslim girls wearing the veil in schools? The paradox is double here. First, this prohibition prohibits a symbol deemed too-strong-to-be-permissible, a sign of one's identity that disturbs the French principle of egalitarian citizenship - the veil itself, from this republican perspective, is a provocative "monstration."

The second paradox is that what France's prohibition prohibits is prohibition itself - and, perhaps, this prohibition is the most oppressive of them all. It prohibits the very feature which constitutes the (socio-institutional) identity of the other: it des-institutionalizes this identity, transforming it into an irrelevant personal idiosyncrasy.

What this act of prohibiting prohibitions creates is the space for the "universal Man" for whom all differences - economic, political, religious, cultural, sexual - are indifferent, a matter of contingent symbolic practices. However, in this space, created by the prohibition of prohibition, while there is no guilt, the absence of guilt is paid for by an unbearable rise of anxiety. The prohibition of prohibitions is a kind of "general equivalent" of all prohibitions: a universal and thereby universalized prohibition, a prohibition of all actual otherness.

Therein lies the paradox of so-called tolerant multiculturalism: the more it is tolerant, the more it is oppressively homogeneous. Martin Amis recently ridiculed Islam as the most boring of all religions, which demands that its believers perform again and again the same stupid rituals and learn by heart the same sacred formulas. But in fact, it is multicultural tolerance and permissiveness that represent the true boredom.

But if, following Nietzsche's equation of truth and woman, we transpose the feminine veil into the veil which conceals the ultimate Truth, the true stakes of the Muslim veil become even clearer. Woman is a threat because she stands for the "undecidability" of truth, for a succession of veils beneath which there is no hidden core. Precisely by veiling her, we create the illusion that there is, beneath the veil, the feminine Truth - the horrible truth of lie and deception, of course.

To illustrate this point, recall the 1939 Hollywood melodrama, Beau Geste . In this film, the oldest of three brothers who live with their benevolent aunt, in what seems to be an act of incredible cruelty, steals the priceless diamond necklace which is the pride of the aunt's family, and disappears with it, knowing that his reputation is ruined, that he will be forever known as the ungrateful embezzler of his benefactress. So why did he do it?

At the end of the film, we learn that he did it in order to prevent the embarrassing disclosure that the necklace was a fake: unbeknown to everyone else, he learned some time ago that the aunt had to sell the necklace to a rich maharaja in order to save the family from bankruptcy, and replaced it with a worthless imitation. Just prior to his "theft," he learned that a distant uncle who co-owned the necklace wanted it sold for financial gain. If the necklace were to be sold, the fact that it is a fake would undoubtedly be discovered, so the only way to retain the aunt's and thus the family's honour is to stage its theft.

In other words, the crime of stealing is committed in order to conceal the fact that, ultimately, there is nothing to steal! Therein resides the concealed scandal of Islam: only a woman, the very embodiment of the indiscernability of truth and falsehood, can guarantee Truth. For this reason, she has to remain veiled.

This brings me back to the topic woman and the Orient. The true choice is not the one between Near-Eastern masculine Islam and Far-Eastern feminine spirituality (now so attractive to the West), but between the Far-Eastern elevation of woman into the Mother-Goddess (the generative-and-destructive substance of the world) and the Muslim distrust of woman which, paradoxically, in a negative way demonstrates more directly the subversive-creative power of feminine subjectivity.

Let me illustrate this by means of an unexpected reference to a simple work of art. The item numbered PO 24.1999 in the Museum of Islamic Art in Doha is a tenth century earthenware circular dish from Iran or Central Asia. It is 43 cm in diameter, and decorated with black writing on white slip is a proverb attributed to Yahya ibn Ziyad reading: "Foolish is the person who misses his chance and afterwards reproaches fate."

Such dishes were meant to solicit an appropriate conversation among the learned men during and after the meal - an ancient and, alas, forgotten art whose last great practitioner was perhaps Immanuel Kant. Such practice is foreign to our fast-food times when we only know business meals ("power lunches"), but not "thinking meals."

What is message of this dish? Just reflect on the temporal dimension of using the dish: when, at the beginning of the meals, eaters first perceive the inscription on the edge of the full dish, they dismiss it as a mere platitude, a lesson about chance and the opportunistic ability to seize it, and wait for the "moral" lying concealed beneath the pile of food. Once the dish is empty, however, they see that the hidden message is the bare platitude. They then realize they had missed the truth in the proverb and so return to it; and upon reading it again, they realise that it is not about chance versus fate, but about something much more complex and interesting: how it is in their power to choose their fate.

This message has touches on the very core of the Muslim experience overlooked by Western Christians. In the Nazi concentration camps, the "living dead," the prisoners who had lost the will to live and just went through motions, were called "Muslims" (the irony of it being that most of them were Jews!). This naming expresses the Western cliche about Muslims as passively surrendered to divinely ordained fate (and then, of course, we are reminded that "Islam" means "surrender").

But a close reading of Yahya ibn Ziyad's proverb - which is ultimately not a proverb at all, but a crucial philosophical insight - quickly shatters this cliche: we place the blame on fate when we miss a chance - but which chance? The chance not simply to act freely and seize the opportunities presented to us, but the chance to choose what we perceive as our fate, to choose a different fate.

In the suburb of Doha, there is a camp for immigrant workers - the lowest among them on the social scale come from Nepal. They are only free to visit the city centre on Fridays. However, on Fridays, entry into a shopping mall is prohibited to single men - officially, to maintain the family spirit in the malls; but this, of course, is only an excuse. The true reason is to prevent immigrant workers from mingling with wealthier shoppers (immigrant workers are alone in Qatar, they are not allowed or cannot afford to bring their families with them).

Let us then step down from the archaeological and art-historical heights into ordinary life. Let us imagine a group of poor Nepali workers resting on the grass south of the central souk in Doha on a Friday, eating a modest meal of hummus and bread on our dish. Upon finishing the meal, they confront the words of Yahya ibn Ziyad and engage in a conversation - and one of them says: "But what if this applies also to us? What if it is not our fate to live here as outcasts? What if, instead of bemoaning our fate, we should seize the chance and change this fate?"

And why should we not take a step further and - back to the scene of Nepali workers eating from a plate - imagine a woman (also an immigrant worker, say, whose job is to clean rooms in a hotel) who serves them food on our plate? What if she has wisely chosen this dish to remind men of the truth that her own subordination is also not fate - or, rather, that it is a fate which can be changed?

We can see how, although Islam constantly receives bad press in the West for the way it treats women, there is a unique potential concealed beneath the patriarchal surface.

This, then, is the message of the item numbered PO 24.1999 in the Museum of Islamic Art. Insofar as we tend to oppose East and West as fate and freedom, Islam stands for a third position which undermines this binary opposition: neither subordination to blind fate nor freedom to do what one wants - both of which presuppose an abstract external opposition between the two terms - but a deeper freedom to choose our fate.

Slavoj Zizek is the International Director of the Birkbeck Institute for the Humanities, University of London, and one of the world's most influential public intellectuals. His latest book is Less Than Nothing: Hegel and the Shadow of Dialectical Materialism.