Richard Dawkins stands accused of cowardice for refusing to debate with an Amercian theologian, William Lane Craig. He responds that he's too busy and that Craig is nothing but a professional debater.

Naturally, Dawkins is under no obligation to take part in someone else's publicity tour, but the allegation does have some force, not least because Craig has a reputation for eating atheists for breakfast.

Even Christopher Hitchens, it is generally conceded (even by atheists), lost his encounter with Craig on points.

Theatrical debates about the existence of God rarely change minds – least of all those of the protagonists – and William Lane Craig's undoubted skill as a debater may have little to do with the strength of his arguments. Nevertheless, it is regularly claimed that "new atheists" such as Dawkins are not intellectually outstanding. The critic Terry Eagleton, for example, though not a believer, has berated him for, among other failings, not having properly thought through "the epistemological differences between Aquinas and Duns Scotus".

Perhaps we shouldn't be too surprised by Dawkins's lack of philosophical sophistication. He is, after all, a biologist. As such, he is well qualified to rebut the claims of creationists.

But the "argument from design" is only one of the usual proofs of God's existence, and the one most vulnerable to empirical assault.

Religious philosophers, moreover, have had centuries to perfect their arguments for the existence of God. Such arguments might not be successful, in that they don't convince atheists, but then there has never been a really convincing philosophical argument for the non-existence of God. There hasn't needed to be.

The default setting

Perhaps the atheists' collective failure in debates with skilled believers such as Craig is only to be expected. Essentially, they have to try harder.

An atheist is like the lion running for its dinner – victory is desirable but not crucial. Theists need better arguments – like the gazelle running for its life – because they need to, as the default setting of our society is now atheist, or at the very least agnostic.

Whatever the beliefs of individual scientists, science is a fundamentally atheistic endeavour. By which I mean that no single scientific theory – if one ignores the quasi-scientific concept of Intelligent Design – relies on or invokes God. An explanation of science that depended on God would not, in scientific terms, be an explanation at all.

But then no historian, searching for the root causes of significant events, considers divine intervention, either: even the Holocaust, which clearly raises questions for theology, does not raise theological questions for historians.

Trial by jury long since replaced trial by ordeal. It would be considered outrageous for parliament to legislate against adultery, homosexuality or witchcraft. And while American politicians, unlike their British counterparts, are notorious for frequently mentioning God, even they would not respond to – say – the Deepwater Horizon oil spill by praying. Religion, in short, has not so much been disproved as put firmly to one side.

For most of history, in most societies – in ours until a few centuries ago, in many parts of the world even today – religion has permeated the whole of life and the entire culture.

Before the Enlightenment, it would not have seemed strange to explain historical processes, the rise and fall of nations and of individuals, with appeals to divine providence. The belief that species were individually created by God formed the whole basis of biological understanding. Even Newton's physics depended on a philosophical God to set up the cosmic clockwork and keep it ticking over. Moreover, the greatest art, the greatest music, the greatest literature was steeped in biblical themes.

Assume the position

In such a culture, atheism was aberrant; God was simply assumed, incorporated unconsciously into areas of life and thought that we today would regard as wholly secular. Atheism, if it existed at all, was generally a private scepticism rather than a public platform. Even David Hume never claimed to be an atheist.

These days, by contrast, atheism is easy. It requires no special thought – indeed, it requires no thought at all – because it is perfectly possible for anyone to live a normal life without religion, and religion is the only domain in which God maintains any sort of meaningful presence. (Although there are theologians who would evict God even from there.)

Naturally, many people continue to believe in God, and their belief may cause them to advocate certain public positions – obvious examples being opposition to free abortion and support for marriage. Even such campaigners use secular or quasi-secular arguments, however, when trying to make their case.

What they do not say – as in a non-secular culture they might – is that abortion angers God, and that it should be banned because anyone participating in it will go to hell.

To articulate a convincing case for God in a society that functions almost entirely on the assumption of his non-existence is, therefore, no easy proposition. It requires intellectual flexibility, imagination, an ability to look beyond the obvious. As such, we should expect believers to win debates with atheists. Needless to say, it does not mean that they are right.

Nelson Jones runs the Heresy Corner blog. He was shortlisted for the 2011 Orwell Prize for blogging.