What, in your view, were the defining characteristics of the Catholic Inquisition from the 13th century onwards?
The defining characteristic of the Inquisition was that it had what we think of as modern tools available to it. These include things such as a bureaucratic structure and the ability to collect information, preserve it and then find it again. This kind of ability was relatively new.
That's why I think of the Inquisition as modern. Once you cross this threshold and you have these capabilities, things such as inquisitions become an enterprise that many institutions, governments and other groups can pursue.
But your argument is not just about the technology of inquisition.
My point is that the inquisitorial impulse - the notion of "my way or the highway" - is never enough. It's an essential precondition but, without the infrastructure, it just isn't going to have the kind of staying power that an inquisition needs to have.
That said, the attraction of moral certainty has, I think, become more powerful in the modern age. If you look at the history of the past 700 years or so, you see one after another these powerful spiritual or philosophical systems sweeping across parts of the world with the terrible insistence that this is the one right way and for everyone's good we must impose it.
That impulse is not only religious, is it? There are secular versions of it, too.
Today, we are living with one of the spiritual versions, which is Islamic. And within the Catholic Church, this tendency towards the control of ideas
is, to put it mildly, not absent. But it is a mistake to think of it as confined to the religious dimension - it palpably is not. And we've seen it over the past century and a half.
You write about the role that doubt plays in Catholic theology. Are the doubters winning in the Catholic Church today?
I think that the doubters are winning and will win, though it often doesn't look that way. This is a faith with a billion people in it and, ultimately, the Church follows the congregation, much as the Vatican may not want to see it that way.
What was the initial impulse for God's Jury, your book on the Inquisition?
Three impulses combined to bring the book about. First, I had come to know a great many theologians who had run into trouble with the Vatican. That made me think of the Inquisition as something that was still going on in some fashion.
Second, one of those theologians mentioned to me that the Congregation for the Doctrine of the Faith (CDF), the theological watchdog, has its offices in the old Inquisition palace. That seemed like a PR move from hell!
The third thing was the aftermath of 9/11 and the extent to which we seemed to be ploughing very familiar ground.
Does the spirit of the Inquisition survive in the activities of the CDF?
Yes, it does. It is not burning books any longer and it's not burning authors, so some of the spirit has gone out of the enterprise. But the motivation is still very similar.
That said, there's a limit to what the Church can do to punish people these days. It really only has leverage on you if you are a loyal member of the Church. If you're not, it can't touch you. But if you are, it can do things. It can say, "You can't have this title." It can move you out of a job.
Has the Vatican taken an interest in the book?
I've been fervently hoping it would condemn it! If only it would bring the index back, just for this book. But it hasn't shown any signs
God's Jury ends with a plea for humility about human capabilities. I was reminded of that line of Kant's: "Out of the crooked timber of humanity, no straight thing was ever made."
That's such a wonderful phrase. I've always found, philosophically, the recognition of weakness, fallibility, error, the propensity
to take the wrong path, properly understood, to be a source of strength, rather than an avowal of weakness.
Cullen Murphy's "God's Jury: the Inquisition and the Making of the Modern World" is published by Allen Lane (£25)