PW: You were once an atheist. What happened to that commitment?

Alister McGrath: I began to change course when I left Northern Ireland, which in those days was a very religiously polarized place. I went to Oxford to study chemistry and suddenly found myself exposed to articulate versions of Christianity. And I experienced a growing sense of the intellectual vulnerability of atheism, along with a realization that perhaps I'd been rather hasty in dismissing Christianity. In preparing to write this book I went back to atheist texts, some of which I hadn't read in quite a long time, and I found myself asking, "Why was I so taken with that argument? Why was I so impressed by that thought?" It was a strange feeling, I have to say.

PW: You define atheism not just as the absence of belief, but as a definite set of principles.

AM: Clearly there are quite a few people who don't believe in God at the moment, but they are keeping the question open. I would argue that it's misleading to call those people atheists. "Uncommitted" or "undecided" would be a better way of referring to them. So in this book I define atheism not as a suspension of decision, but as a principled decision to live and act on the assumption that there isn't any God or any spiritual reality beyond what we know.

PW: And you find that atheism is declining?

AM: There's no doubt that fewer people define themselves as atheists. In fact, I discovered that atheists tend to be older. Younger people tend to say something like, "Well, we're very interested in spirituality." They refer to atheism in quite cautious terms: how can you be so dogmatic when we don't really know?

We can't predict atheism's future with certainty, of course. Atheism is partly reactive. Its fortunes lie in religious people not doing stupid things because when they do, it can drive other people to disillusionment with religion and even to atheism. And you can't predict that. But if present trends continue, I don't really see much of a future for atheism.

PW: Why was atheism so attractive for a time?

AM: Protestantism was partly responsible. Protestant worship, which often minimized the sense of the immediate presence of the divine, really encouraged people to think of a world in which God cannot be experienced. And if you don't experience God, it is not a very long step to saying there might as well not be a God. As people began to look for more, and especially to ask what sort of imaginative world Christianity engenders, they found it stale and unappealing.

Today, we don't have to imagine a godless world, because we've seen it. The imaginative potential of atheism has been eroded because we've been there, we've done that. The Soviet Union in the 1930s was hardly very exciting. But at the same time there was a recovery of the religious imagination. Just look at the recent success of Mel Gibson's Passion and Tolkien's The Lord of the Rings, each in its own way an imaginative explication of some central Catholic themes. The Christian artists have made a kind of comeback.

PW: What can Christians like yourself learn from atheism?

AM: It's clear that atheism's appeal is situation-specific—in 1789 in France, for example, it was immensely attractive. It seems that when Christians, or any religious people, get into power and abuse that power, atheism becomes a very attractive option. This is not without relevance to the contemporary political situation in North America. Evangelical Christians have gained a significant amount of power in the past quarter-century, and I occasionally wonder whether they have the necessary history and experience to cope with this. It brings temptations and responsibilities which I'm not sure the movement has quite prepared itself for.

PW: And how have atheists responded?

AM: This book began at a debate on atheism at the Oxford Union in 2002. Though my atheist friends don't agree with me, they do say these are interesting arguments that need to be talked about. The key thing for me is to open up a discussion. It would be good for atheism and good for Christianity to talk about these things quite openly, and if this book gets a discussion under way I'll be delighted.