St Augustine was probably the first major thinker to discuss at length how states use enemies for their own internal purposes. He traces with acid clarity the way in which the Roman Republic begins to collapse from its inner tensions and conflicts once Carthage, the great historic enemy, has been destroyed, and concludes that if you have no means of generating coherence and justice within your own polity, you will always be on the lookout for new enemies on to whom you can displace the threats arising from your own political failures.

It is an analysis that applies with uncanny accuracy to a range of modern political phenomena, from the insanity of the nuclear arms race in the Cold War to various more recent mythologies, including some popular characterisations of “the West” against “the Muslim world”. Noel Malcolm’s brilliant study looks at a period not wholly unlike the Cold War: the three centuries during which the Ottoman empire was the unsettling Other to the Western Europe of early modernity. It was a period of sporadic (sometimes very extreme) military collision and long stretches of uneasy stand-off, complicated by the fact that the empire could be and was drawn into the diplomatic and military conflicts between Western states. Malcolm has some wry and intriguing pages on the theological gymnastics required to justify the fairly consistent pro-Ottoman diplomatic policies and strategic alliances of the “Most Christian” kings of France.

But his interest, as he states clearly in his introduction, is not so much in the details of diplomatic relations (though the book is a splendid guide to much of this history), nor in the actual development of social and political institutions in the Ottoman world. The focus is on the ways in which Western thinkers used what they knew about Islam and the Levantine world to make points to their own European readership. The utility of having on hand a sort of reversed image of one’s own society is not only its helpfulness for rallying people in solidarity against a manifest threat; it is also about how the real and imagined strengths of this enemy throw light on the failures and weaknesses of one’s own environment.

In the process that Malcolm nicely calls “shame-praising”, Western intellectuals can point to the discipline of Ottoman armies, or the visible piety of Muslim citizens, or the orderliness of Levantine households in order to reproach their own societies. Muslim forces are prevailing against Christian ones because Muslim populations exhibit virtues that Christians have forgotten – despite the superior truth of Christian teaching and the innate feebleness of “Orientals” in general (thanks to the hot climate of the region, apparently, which suggests that not enough of these experts had spent time in Thrace or Anatolia in November).

Malcolm warns us against taking language appreciative of Muslim societies at face value. He is rightly critical of scholars who have dubbed some 17th century writers as “Islamophile”; they have failed to see that Christian commentators on the Muslim and Ottoman worlds (virtually synonymous in the eyes of most Christians at this time, though some show an awareness of the difference between the Near Eastern, North African and Balkan territories of the Ottoman empire, and the very distinct environment of Persia) will happily deploy contradictory tropes. They may deplore Ottoman tyranny and cruelty, and praise Ottoman discipline and efficiency; magnify the threat of Ottoman expansionism and predict the imminent collapse of the empire depending on the precise point they want to reinforce for home consumption.

There is much illumination here about the intricacies of Western perceptions of Islam as a religion, and on the tension between two competing medieval models of Muslim belief, a tension that survives in one form or another well into the early modern period. Is Islam a distorted form of Christianity, a heresy? This was the general view of polemicists in the Byzantine empire, and by the 12th century it was transmitted to the medieval West, when Latin translations of the Quran were beginning to appear. But it stood alongside a rival picture in which Muslims were simply “infidels”, the equivalent of pagans and (ironically, given the Muslim condemnation of image-worship) idolaters, devoted to a false God.

The further twist of irony is that there were real advantages for Muslims in being classed as pagans when they lived within Western societies or under Christian rule; it meant that they were not subject to the draconian penalties for heresy. It helped to be more rather than less “Other” for certain purposes. Conversely, it was something of a challenge to Western orthodoxies that the Ottoman empire was unusually tolerant of religious diversity (though the Western texts that use this to condemn official intolerance in their own setting rarely, if ever, make any effort to explain the civic disabilities of non-Muslim populations in the Ottoman empire).

Once again, contradictory points were being made for internal Western audiences: the Muslim state was one in which religious and secular authority were combined, yet it was less intolerant of religious minorities than Tudor England; or, because the Sultan was supreme in both religious and secular matters, he was an exact image of the corruptions of the papacy. Playing the Islamic card in these and other ways was an effective tool of both Protestant and Catholic pamphleteers in the 16th and 17th centuries.

But as time went on and the level of familiarity with the actual teaching and practice of Islam grew in the West, the inherited models became harder to sustain. Malcolm gives a fascinating account of how traditional polemic against Islam acquired a new and subversive dimension in the course of the 17th century. It had been conventional to describe Muhammad as an ambitious fraud – one of the legacies of the “heresy” model for Islam, as all major heresiarchs were routinely presented as deceiving their followers for personal gain or advantage. But as confidence in claims to supernatural revelation weakened in the West, there was a gradual recognition that any claim to an authority based on revelation could be represented by a hostile observer in much the same way. What was said about Muhammad could be said about Moses; and even if hardly anyone dared to suggest that the same might apply to Jesus, it could certainly be applied to Paul and other early Christian teachers.

In other words, anti-Muslim polemic gradually turned in some quarters into a sort of universal acid to dissolve all traditional religious claims. Or, if it did not go quite that far, it could prompt some Christian or para-Christian radicals in the 17th century to suggest that Muhammad was in fact the ancestor of revisionist Christianity, opposed to the mystifications of Trinitarian theology, priestcraft and superstition.

Here is one of the many ironies that this book highlights. If Islam was seen as the Other of an orthodox and traditional Christian West, this also meant that Western critics of that tradition could interpret it almost as a beacon for Western reform – for “modernity”. And Malcolm traces with great subtlety how something of this emerges also in the uses of Muslim-related tropes in political philosophy.

In three admirably lucid chapters on “despotism”, he outlines a succession of characterisations by Western writers of Ottoman polity as “despotic” – that is, as a system of untrammelled and arbitrary government where all authority is concentrated in a single sovereign figure. In contrast to Western monarchies, the Ottoman sovereign was not embedded in a complex of subsidiary and interdependent jurisdictions or bound by feudal reciprocities. Just as the Muslim religious world presented an austere landscape purged of the clutter of saintly mediation, sacramental duties, priestly control of the laity and so on, so the Muslim political environment similarly offered a drastically simplified and centralised picture, with no connection between public status and traditional land ownership, no entrenched hereditary nobility, no dense fabric of “rights” and “estates” and mutual obligations such as characterised Western monarchies. A regular cliché was that the Sultan’s subjects were his “slaves”, deprived of the protections of common law and feudal solidarity.

This could be set out as a condemnation of Ottoman polity – and so as an oblique warning to Western monarchies not to go down this alien route – or as a demonstration that the logic of all monarchical government inexorably led to slavery. It could also be seen as something rather enviable: the “modernising” trends in Western monarchies that sought greater central power for monarchs and a reduction in the untidy multiplicity of feudal networks and quasi-independent jurisdictions could find in Islamic polity (as understood by some observers) a pattern worth contemplating in a more positive way. Just as a 17th-century Unitarian rejecting the the Christian Trinity in the name of up-to-the-minute intellectual consistency might see Islam as an early template for doctrinal reform, a 17th-century political theorist might consider the Sultan’s position as the single, unequivocal source of legitimacy to be a quite appealing version of the direction in which the rational state ought to be going.

The extensive reforming activities of Suleiman “the Magnificent”, for example, whose long reign spanned the central decades of the 16th century, left a lasting impression on Western minds of what could be achieved by coherent and forceful direction on the part of a strong monarch. Agricultural and military reorganisation, rational systems of taxation and the reinforced legal protection of religious minorities all offered diverse interest groups in western Europe an enviable model.

Of course, much of this rested on significantly distorted understandings of Ottoman polity, let alone Islamic law. A good deal of what is written in this period about the “despotic” authority of the Sultan shows not the least grasp of Islamic jurisprudence – though there are some laudable attempts to correct this ignorance and to establish that, in terms of property law, for example, the Sultan had no authority to override existing rights. But it was a persistent myth well into the 18th century.

Malcolm discusses at length the portrait of despotic government painted by Montesquieu in his classic treatise on The Spirit of Laws (1848), and notes its influence on other writers of the period such as Turgot. The latter describes despotic rule as involving the control of a population by targeted educational strategies, and also depicts the process of building up a despot’s image as both remote and at the same time capable of terrifyingly unpredictable incursions into all areas of civil life. It has little to do with 18th-century Turkey, but is an uncanny adumbration of more recent totalitarian methods of rule.

Interestingly, Turgot sees Islam as intensifying the “Asian” tendency to despotic rule, as the Ottoman empire is, in his eyes, so much more arbitrarily governed than China or Japan. Like Montesquieu, he is innocent of any knowledge of Islamic law; his concern is to create an ideal type for the purposes of argument. And those who responded to Montesquieu, Turgot and others in defence of the Ottoman system did not fail to observe that centralised and “rationally” absolute government (ie government with a single clear sovereign power from which there was no appeal – not the same as despotism) offered better security for private property than the confused pluralism of older Western patterns.

What Malcolm triumphantly establishes, with a wealth of scholarship drawing on primary sources in many languages, is that the Ottoman empire, and to some degree the wider Islamic world, provided for early modern Europe not just a diabolical opposite to be condemned and resisted at all costs, but a sounding board for some fundamental thinking on religion and politics: about the jurisdiction of the state in religious affairs; the nature of sovereignty; the limits of religious toleration; the importance of standing armies for a stable state; the relation between local ethnic identities and homogenised multinational administration; and a good deal more.

The book’s importance is thus not only to do with its nuanced account of the varieties of western European responses to Islam – though this is valuable enough, if only to show how inadequate is the narrative of a static and “medieval” Islam confronting a dynamically changing western Europe. It is also about how Europe has thought through – and often failed to think through – its own political identities. The Ottoman Other prompted Western thinkers to a variety of what were in effect thought experiments about politics, couched as descriptive essays; political philosophy disguised as social anthropology, in a style that continued to characterise Western accounts of “alien” societies for quite a long time.

Malcolm leaves us with an abundance of pertinent contemporary questions: how do we now use “enemies” to define ourselves? How do we now think about the balance between a sovereign power that guarantees universal legal equality and the need to recognise the reality of diverse affiliations and solidarities that are not dependent on the state? How do Muslim majority states in the modern world balance legal or civic equality with the priority of the needs or rights of the community of faith?

But perhaps his most important contribution is to help us think again about the clichés we still recycle that presuppose a radical ideological incompatibility between an innately pre-modern Islam and a timelessly liberal or pluralist West. Western arguments about Islam and Christianity helped to shape the vocabulary of Western thinking around sovereignty and law, even if they rested on a woefully one-sided version of Ottoman polity. And in these arguments, Islam could be deployed in various ways, including being seen as a kind of first draft for religious and political futures in western Europe.

As Malcolm insists, in a brief but pungent couple of pages in his conclusion, an analysis of early modern versions of the Levant in terms of “Orientalism”, the reductive exoticising of an alien society, is deeply misleading. Without blurring the basic points of real diversity, religious and social, between western Europe and its menacing, tantalising, enviable and bewildering neighbour, Malcolm prompts us to ask not only how the West got to be “modern”, but whether the categories of “modern” and “pre-modern” are as clear cut as we might have thought when we try to do justice to our global political environment.

The West did not arrive at its current “rational” self-depiction by the exercise of abstract, enlightened reasoning but by negotiating complicated arguments about its convergences and differences with a formidable antagonist, thinking through its own internal tensions via the medium of speculation, observation, polemic and semi-fiction about that useful enemy.

Rowan Williams is a theologian and poet. He writes on books for the New Statesman