The threat of ‘Islamic terror’ is just one example of a broader trend in which religion seems to be making an unexpected comeback into public life. Islam of course is hugely salient to politics not only in the Middle East and Asia, but also, increasingly, in Western societies. Everyone from newspaper columnists to Muslim reformers has accused the British Muslim community of being ‘in denial’ about the role of Islam in the current terror threat. In a different way, Christianity too is not only spreading in the form of Pentecostalism in Africa and South America, but also seems as influential as ever in US politics, and was seen as a key factor in George W Bush’s reelection last year.

For a long time people assumed that modernisation meant secularisation, that material progress tends to satisfy people’s needs and cohere society without the need for religion. More recently, this notion seems unsustainable. The prominence of religion in the West suggests that it is not enough to dismiss religion as an expression of backwardness or a source of solace for the poor and hopeless. The four zealots who bombed London on 7 July were British Muslims, not desperate Palestinians.

And while Christianity is less fashionable in Europe than in the American midwest, the indications are that it has been replaced by a vague spiritualism rather than a robust humanism. Researchers from Lancaster University have shown that ‘holistic’ practices such as meditation and yoga are becoming increasingly popular as traditional religion declines. Meanwhile, for all its hostility to the Catholic Church, Dan Brown’s phenomenally popular book The Da Vinci Code trades on mysticism and a prurient interest in religion rather than a atheistic rejection of it. What connects hardline religiosity and fanaticism with New Age-style spirituality is a disavowal of mainstream Western values, which are disparaged as soulless and materialistic.

In fact, the revived salience of religion says more about the limitations of secularism than the depth of religious feeling or the resonance of religious ideas. As the American author Alan Wolfe notes with respect to Evangelical Christianity in the US, avowed religiosity is perfectly compatible with participation in secular society: Christians are remarkably similar to everyone else. This makes it difficult to identify what contemporary religion represents. Increasingly, though, religion addresses needs that for much of the modern era have been the province of politics, providing its adherents with a sense of identity and a connection to something greater than themselves. But religion lacks the earthly foundation of nation or class, and thus religious identities are fickle: the same faith takes on wildly different forms in different contexts. Arguments about whether Islam is a ‘warrior faith’ or a ‘religion of peace’ miss the point: it is whatever its adherents need it to be. In practice, all religions tell us more about the needs of the people who practise them than they do about eternal truths.

If the Church of England was once ‘the Tory Party at prayer’, bound by social and political ties rather than religious feeling, the American religious right is more like the Republican Party praying for its own salvation. The frantic rhetoric of ‘values’ reflects the disorientation of American politics that has been acute since the end of the Cold War. Looking to the Ten Commandments as a guide to the good life is a sign of desperation rather than serious religious conviction. The same certainly goes for the ‘ummah’ or imagined world community of political Islam, an idea which has become popular only with the demise of the national liberation movements that once expressed the aspirations of people in the third world and their sympathisers in the West.

Religion gives form to people’s yearning for meaning, but in itself it offers little in the way of practical guidance. What is disturbing is that contemporary secular society seems to lack the means to pursue this deeper truth in its own terms. The continuing salience of religion-as-myth at a time when it is widely recognised as such is testament to the spiritual emptiness of contemporary society. But the popular yearning that breathes for religion is too self-conscious to resurrect it.

A desire for shared values and meaning is not enough to support religious practice, as opposed to vague sentiment. Just as, in the US, the religiously-loaded rhetoric of values masks a deeper uncertainty, and is all too compatible with the consumer culture it purports to oppose, for many young Muslims in the UK, too, Islam is a punkish lifestyle choice rather than a profound inheritance, offering a means of showing their alienation from British society, and promising some sense of meaning beyond the banalities of everyday life. Even in its extreme and violent form, Islamic fundamentalism resembles nineteenth century nihilism rather than religion in any profound sense. It is an angry reflection of the emptiness of Western society itself. Its consequences are disastrous, but intellectually it is little different from New Age mysticism, with all the religious seriousness of yogic flying. Not for nothing are its adherents known to mainstream Muslims in the UK as ‘nutters’.

It is not enough to dismiss any of these phenomena as irrational throwbacks, however: they are more like inverted expressions of a troubled secular culture. The challenge for secularists is not to refute religion in its own terms, but to address some of the questions for which people are seeking religious answers, questions contemporary politics leaves for dead: the meaning of sex, death, the good life, who we are and what kind of society we want to live in.

The ‘backwardness’ of religion is not instrinsic to any particular dogma or practice, nor even in the irrationalism of faith in general. There is a place for passionate commitment in the most enlightened secular society, and there is no reason this should not be informed by religious tradition. It is the resort to religion as a substitute for political change that is ultimately conservative.