Devilish conceit

ON THE MORNING OF 11 SEPTEMBER, 2001, I TOOK the short route up the hill from the Potomac river to Georgetown University in Washington. It begins with a long flight of steep stone steps, rising up the narrow canyon between two high walls. Even if you've never been to America there is a good chance you have seen those steps, for they feature in The Exorcist, widely regarded as one of the most terrifying films ever made.

I soon learned of the attacks on the Twin Towers and the Pentagon and, amid fears that another plane was heading for DC, the university was evacuated. As I headed back down the steps, I thought of the violent film deaths of the movie director character, Burke Dennings, and the exorcist, Fr Karras, both crushed by falling from on high. At the time I was writing a book on religion, and in one chapter I drew parallels between the spiritual conflict related in The Exorcist and the "battle between good and evil" expressed both by the US and its attackers.

A while later, a copy of my book - An Intelligent Person's Guide to Religion - was bought by William Blatty, author of the Oscar-winning screenplay and of the novel upon which it was based. Hearing that he was intrigued by the use I had made of his theme, I suggested we meet. It looked unpromising; at 77 he is still hard at work and tends not to give interviews. But in the event he was welcoming.

Blatty was born in New York to Lebanese parents. His great uncle, Germanios Mouakad, was a bishop of the Melkite Catholic church, and a leading middle-eastern philosopher. After Jesuit schooling in Brooklyn, Blatty went to Georgetown, and then to George Washington University to study English, where he excelled. In 1951 he joined the air force, becoming chief of policy in the psychological warfare division. Following service in Beirut he moved to California and began publishing novels, which led to scriptwriting and working on films, including the 1964 Pink Panther sequel A Shot in the Dark. Towards the end of that decade Blatty sat down to explore an idea that had been with him since college.

"As a student I realised that if Christianity is true, then nothing is as important as faith and the life of the world to come," he says. "I heard about an exorcism sanctioned by the Church, and thought that if this could be confirmed it would help answer questions about belief, because if there were demons then why not angels, and surely there was likely to be a God. Years later I thought, 'why not go back and investigate the exorcism case?' The priest involved, Fr William Bowdern, had kept a diary of events and told me that he had no doubt it was 'the real thing'. Listening to him and learning about experiences witnessed by non-religious observers, I felt this was more than a story; it was testimony to a supernatural reality."

The resulting novel, The Exorcist, was a hit, with 13 million copies sold in the US alone; and the movie quickly acquired classic status. The sequel, Exorcist II: The Heretic, not Blatty's, proved a flop; but he wrote a follow-up novel and later directed an adaptation, Exorcist III: Legion (1990) starring George C Scott as the philosophical Jewish detective Kinderman. The title comes from the story of Jesus casting out demons. He asks: "What is your name?" The reply: "My name is Legion, for we are many."

Blatty set one condition for our meeting - I must first read Legion. I am glad I did, for behind the possession stories lies a speculative mind trying to answer two ancient questions: what is the source of order and the meaning of evil?

Blatty's directorial debut was 1980's The Ninth Configuration, another book adaptation, for which he won a Golden Globe. One character comments: "In order for life to have appeared spontaneously on Earth, there first had to be hundreds of millions of protein molecules of the Ninth Configuration. But, given the size of the planet Earth, do you know how long it would take for just one of these protein molecules to appear by chance? Roughly ten to the 243rd power, billions of years; and I find that far, far more fantastic than simply believing in a god."

Kinderman arrives at a similar conclusion in Legion, but it leads to a puzzle: "Design and causality, he thought. God exists. I know. Very nice. But what could He possibly be thinking of? ... A god who was good could not help but intervene upon hearing the cry of one suffering child. Yet he didn't. He looked on." So, the order of the world suggests a creator God, but the evil in it seems to exclude this. What are we to think? Blatty has an answer, the first part of which has familiar philosophical precedents but the second could hardly have been guessed at.

Kinderman wonders: "Was the three-dimensional universe an artificial construction designed to be entered for the working out of specific problems that could be solved in no other way? Was the problem of evil in the world by design? Did the soul put on a body as men put on diving suits in order to enter the ocean and work in the depths of an alien world? Did we choose the pain that we innocently suffered?" Blatty's reply is arresting. Suppose we did choose. In Legion the suggestion is that we are parts of a single spirit that wanted to love the creator. To do that we needed to make our way through the world and back to God. But at that stage there was no material universe. There was only God and the spirit of light that we then were, whose legendary name is Lucifer. The creator let us become material, and that's how the physical world was made.

Blatty handed me part of the draft of a book he is working on, Dimiter, in which he takes his theory further. The story is set in Albania and Jerusalem. This time a priest explains the combination of order and suffering, of good and evil. "'Before the beginning,' urged the priest, in some Elsewhere, we were a single titanic being. Then something happened, some decision was made that we dimly recollect as The Fall. A means of salvation was offered. We took it. Exploding from oneness into multiplicity, we became the physical universe, space-time, light cloaked in matter, for in no other way but in bodies could we risk, could we grow and evolve back into ourself ... Consider: all matter is finally energy. And what is energy finally? Light! ... 'You were once a bright angel.' Do you see? We are Lucifer, the 'Light Bearer'.

If Blatty's myth is true then there is a fallen angel, but no damned demons; and unlike the Oscar whose gilded skin conceals a base element, the darkness of human lives conceals something immeasurably good: eternal souls made out of and for eternal love. Blatty's mystery tales are not horror stories but metaphysical allegories in the tradition of the ancient, near-eastern cultures: stories his very ancestors might have told.

• John Haldane is professor of philosophy in the University of St Andrews and author of An Intelligent Person's Guide to Religion (Duckworth, 8.99).