Tolerance is a characteristic on which the British used to pride themselves. But the ever more frequent discussion of religion, and how it relates to science and to our much cherished pluralism, is increasingly marked by an absence of that quality. Indeed, debate in this area reminds me of a tradition at my old school called "the house shout", in which the members of two houses would bellow "Up School House" and "Up the Grange" at each other from two sides of a quad, victory being awarded to whichever was judged the more vocal. The contest did provide a certain brute physical exhilaration, but ultimately proved no important point. It was not a conversation. There was no exchange of ideas or attempt to persuade.

Today, we hear far too much aggressive assertion that serves only to increase intolerance and suspicion. It may have been a thoughtless slip, but too often we hear careless generalisations such as the novelist Sebastian Faulks's recent dismissal of the Quran as "the rantings of a schizophrenic". We are familiar with the opinions and sometimes actions of religious fundamentalists in this country - it is less than a year since the home of the publisher Martin Rynja was firebombed because his firm was due to print a novel about the Prophet Muhammad's bride Aisha. But in their words, many of those who seek to defend reason show themselves to be equally unreasonable and inflexible in their views. A gentle and accommodating agnosticism has given way to an angry and insistent atheism that sees offence as the best way to defend rationalism and science.

Going on past correspondences, the sympathies of most New Statesman readers are with the "God-free". There seems to be a widespread feeling that a magazine of the left should not only display a preference for secularism but for atheism, too: that we should take our editorial line from Richard Dawkins and agree with him that religion is, at best, as silly as believing in fairies at the bottom of the garden but is, more generally, "dangerous nonsense" that devalues human life.

But this ignores the deep association in this country between religion and radicalism. The right may see the parable of the talents as a justification for wealth creation, and Margaret Thatcher once pointed out that the Good Samaritan was only in a position to help because he had money; but others have long looked to the man who washed the feet of his disciples and who consorted with outcasts, and have drawn very different conclusions. British socialism, said Harold Wilson, owed more to Methodism than to Karl Marx, while Keir Hardie was even more explicit: "I have said, both in writing and from the platform many times, that the impetus which drove me first into the Labour movement, and the inspiration which has carried me on in it, has been derived more from the teachings of Jesus of Nazareth than from all other sources combined," he wrote in 1910.

Radical predecessors such as the Levellers and the Diggers would have agreed. And the Lollard John Ball's thrilling rebuke to the iniquity of entrenched privilege would be nothing without its biblical reference. "When Adam delved and Eve span," he asked in a sermon during the Peasants' Revolt in 1381, "who was then the gentleman?"

Just as pertinently, to refuse to engage with faith would be to close one's eyes to the reality of belief, both here, where in the last census nearly 80 per cent of the population agreed they had a religious affiliation, and abroad. The Malaysian opposition leader Anwar Ibrahim, admired by thinkers and leaders from Amartya Sen to Al Gore, once commented that Asian man is "Homo religiosus", but the term could be applied much more widely. At a time when the convictions of billions do so much to shape our geopolitics, is it really wise to discount them as misguided delusions?

Much of the current noisy argument comes down to the status of knowledge, and specifically what is commonly deemed as the unbridgeable gulf between "revealed" knowledge and that of science - which Dawkins's ally Daniel Dennett once told me was the "only game in town" when it came to "facts, and the explanation of facts".

But this is an overly narrow view. Religion consists of far more than "revealed" truths, which are, in any case, obviously of a different kind from those derived from theoretical and empirical study. More importantly, this is to claim far too much for that corpus of conjecture we call human knowledge. As a student, I read David Hume's argument that although we may believe the sun will rise tomorrow, we cannot know it. For me, it was as profound and as revelatory as any religious experience, and as convincing as any scientific proof. And I hope that his words will inform the blog on religion, reason, belief and unbelief that I am about to start on Newstatesman.com: "Where men are the most sure and arrogant, they are commonly the most mistaken."

All will be welcome to the blog, those who wish to shout as well as those who wish to converse, religious believers and atheists alike. But it is my conviction that the discussions (in which I hope readers will join me) will develop into debates about matters of belief, whether they be over evolutionary theory, the validity of literal readings of sacred texts, or the boundaries between the religious and the secular. For how many of us can truly gainsay the wisdom of Socrates: "All I know is that I know nothing"?

Sholto Byrnes begins his new God Blog on Monday: www.newstatesman.com/blogs