THIS weekend the World Congress of the International Academy of Humanism takes place in upstate New York. Its theme? “Toward a New Enlightenment”.

To judge from the publicity, the conference organisers have no doubt of the urgency of their theme. Religion is regaining the ascendancy. We are facing a new dark age. Only a return to the Enlightenment can save us. We need to create a road map for a New Enlightenment throughout the world.

Speakers such as Richard Dawkins, Britain’s best-known atheist, will address issues such as the “God Delusion” — one of the many barriers that need to be swept away if humanity is to finally come of age.

It is a fascinating glimpse of the crisis of confidence which is gripping atheism. Belief in God was meant to have died out years ago. When I was an atheist, back in the late 1960s, everything seemed so simple. A bright new dawn lay just around the corner. Religion would be relegated to the past, a grim and dusty relic of a bygone age. God was just a cosy illusion for losers, best left to very inadequate and sad people. It was just a matter of waiting for nature to take its course.

I was in good company in believing this sort of thing. It was the smug, foolish and fashionable wisdom of the age. Like flared jeans, it was accepted enthusiastically, if just a little uncritically.

Everyone knows it has not worked out like that. In The Twilight of Atheism, I try to find out what went wrong for atheism in the past 40 years. There’s lots to find. Hopelessly overstated arguments that once seemed so persuasive — such as “science disproves God” — have lost their credibility. Anyway, our culture’s criterion of acceptability is not “Is it right?” but “Does it work?” And the simple fact is that religious belief works for many, many people, giving direction, purpose and stability to their lives — witness the massive sales and impact of Rick Warren’s The Purpose-Driven Life. Atheism, already having failed to land the knockout punch by proving that God does not exist, has not even begun to engage with this deeper question; instead it mumbles weary platitudes about mythical “God-viruses” or mass “Goddelusions”.

It may once have been bold, brave and brilliant to argue that religion was an infantile delusion or a pernicious superstition. Now, atheism seems arrogant and uncomprehending; incapable of even the most basic act of intellectual empathy that tries to grasp why intelligent, articulate people might choose to believe something which we disagree with — and which might even be right.

The real issue, however, has to do with atheism being trapped in a time warp. Atheism is a superb example of a modern metanarrative — a totalising view of things, locked into the world view of the Enlightenment.

So what happens when this same Enlightenment is charged by its postmodern critics with having fostered oppression and violence, and having colluded with totalitarianism? When a new interest in spirituality surges through Western culture? When the cultural pressures that once made atheism seem attractive are displaced by others that make it seem intolerant, unimaginative and disconnected from spiritual realities?

The obvious answer would be for atheism to undertake a reformation — to examine itself in the light of its failings, and direct towards itself the negative criticism it has until now automatically fired off at anything religious.

The Enlightenment is over, the world has changed, and atheism must change as well. But that is not the answer they are looking for in upstate New York. Instead, they want the Enlightenment all over again.

I’m not an atheist any more. As a Christian, however, I still retain a deep respect for the serious, reflective, intensely moral atheism I find in writers like Ernst Bloch. Religion needs to be criticised, both internally and externally, to remain true to its roots and its heart. Yet its critics need to be credible.

Atheism has, quite simply, lost much of its moral and intellectual cutting edge in recent decades. And unless it sorts itself out, it is not going to regain it.

Alister McGrath is professor of historical theology at Oxford University, and author of The Twilight of Atheism and Dawkins’ God: Genes, Memes and the Meaning of Life