‘Was it mere coincidence that liberal secularism developed in the Christian west?’ With this rhetorical question, Larry Siedentop begins one of the most stimulating books of political theory to have appeared in many years. An intellectual historian who spent most of his career teaching in Oxford, Siedentop believes there was no coincidence involved. Secular liberal values are Christianity’s gift to the world, he believes, and he backs up his contention with a refreshingly unorthodox account of the roots of modern liberalism in medieval Christian thinking. Even if you remain unconvinced by some of its central claims – as I do myself – this is a timely and much-needed corrective to the all too familiar Enlightenment fable in which Christian theism and liberal values are necessarily at odds.

Siedentop begins by explaining how the political thought of the ancient world was bound up with a particular conception of the cosmos and human reason. The ancient idea of reason, he points out, ‘carried within it hierarchical assumptions about both the social and physical world’. Reason was not just a tool that enabled human beings to satisfy their wants but a way of finding the human place in a great chain of being. In this conception, ‘relationships within the non-human world were assimilated to reasons for acting in human life … In the social world, the assumption emerged that there was a natural hierarchy, a superior class entitled by “nature” to rule, constrain, and, if need be, coerce.’ With its view of society seamlessly joined to cosmology and metaphysics, ancient political thought did not recognise the human individual as an autonomous agent and creator of value. Although Siedentop does not discuss them, there were dissenters from this view of things. The Sophistic tradition developed a distinction between nature and convention which supported a belief in human equality. Even so, he is right that an idea of hierarchy in the cosmos shaped much of ancient political thought.

Starting his argument in this way is itself a salutary departure from recent academic convention, which aims to separate political thought from religion and metaphysical belief as far as possible. Not only is such a separation unwarranted, it also prevents us from understanding how many of the ideas of secular discourse were formed and developed within religious traditions. Showing how an ancient conception of the cosmos shaped an assumption of hierarchy in society and government, Siedentop is able to argue that St Paul introduced a revolutionary idea of moral equality before God into Western thought. ‘It is hardly too much to say that Paul invented Christianity as a religion.’ Along with Christianity, Paul also invented the individual. Through his ‘leap of faith in human equality’, the inventor of Christianity ‘turned the ancient world upside down’. Here again one might argue that pre-Christian thinking was less monolithic than Siedentop suggests. Job’s questioning of divine justice was more subversive of the idea of cosmic hierarchy than anything in Paul’s Christianity.

Siedentop is nevertheless right to focus on how much in modern liberalism is a development from Christian ways of thinking. Ranging widely through theological disputation, ecclesiastical law and monastic governance, he shows how ideas of human rights were secreted in the interstices of medieval Christian thought and practice. In an aside, the paradoxical flair of which would have delighted the late Isaiah Berlin, he singles out Tertullian – the early Christian theologian who declared that the tenets of the faith must be believed because they are absurd – as one of the first proponents of freedom of thought and conscience.

Devoted to telling an edifying tale of human advance, conventional histories of liberalism have a habit of passing over the ways in which ideas give birth to new avenues of thinking that may be at the opposite pole to what their original authors intended. Yet Siedentop tells an edifying tale himself when he represents modern liberalism as being the inner logic of Christianity. Not without a flavour of the Whig interpretation of history, even of Hegelian dialectic, his account is too teleological, and also too uplifting, to be entirely credible.

It may well be true that modern liberal values are offshoots from Christianity. Certainly the debt of liberalism to monotheism, which a new generation of secular humanists is so determined to deny, demands a contemporary reaffirmation. But it is not only secular liberalism that emerged from the melting pot of medieval Christianity. So did secular totalitarianism. From Jacobinism to Bolshevism, it is impossible to understand the radical political movements of modern times without understanding their origins in Christian apocalyptic myth. The continuities between medieval chiliasm and modern totalitarianism were shown in Norman Cohn’s The Pursuit of the Millennium, first published in 1957, and Cohn’s insights remain valid today. Christianity is not all of one piece and has not always been benign. Was it mere coincidence that communism and Nazism developed in the Christian West?

Clearly, Siedentop intends his account of liberalism as a remedy against the West’s loss of faith in itself. ‘If we do not understand the moral depth of our condition’, he writes at the end of the book, ‘how can we hope to shape the conversation of mankind?’ But his analysis may be less inspiring than he hopes, for if secular liberal values are a gift of the Christian West, then Western societies cannot possibly be a model for the world – not even the Christian world. Confining his attention to Western Christianity, he leaves the Orthodox tradition on one side. Given that Orthodoxy has not produced anything like the secular values recognised in Western traditions, he may be right to ignore it; but the unavoidable implication is that the West was deluded in expecting anything like itself to emerge in post-communist Russia. If we accept Siedentop’s analysis, the belief that secular values can be securely established in countries that have long been predominantly Islamic looks similarly far-fetched. These conclusions may be well founded. But this is hardly a result that supports Siedentop’s evident conviction that Western liberal values are universally applicable.

Towards the end of Inventing the Individual, Larry Siedentop returns to an earlier book, Democracy in Europe (2001), in which he also argued for the centrality of Christianity in liberal politics. Here he laments what has been called the European ‘civil war’ – the deep divisions that exist on the Continent about the place of Christianity in the state. But it seems to me fanciful to explain Europe’s disunity by reference to religion. The chief cause of European division at the present time is a hubristic project of European union. If disputes about religion are relevant at all, it is only in showing that talk of any coherent body of ‘European values’ is disingenuous and absurd.