William Friedkin has reached the same conclusion as the late exorcist Fr Gabriele Amorth

Any attentive reader of the Synoptic gospels will see that Jesus works a significant amount of miracles in His ministry; when one reads St Mark, thanks to the brevity of the account, it seems that Jesus is portrayed primarily as a miracle worker, and in particular as a Messiah who comes to rescue people from the clutches of Satan by casting out evil spirits. The exorcisms of Jesus dominate the account, and the teaching seems almost a minor theme. It is not what Jesus says that counts so much as what Jesus does. The cures, and in particular the casting out of evil spirits, inaugurate the Messianic age, and the restoration of friendship between God and the human race.

There are several possible historical reflections on Jesus’s casting out of devils. One is that there were more cases of demonic possession at that time than before or since; or else the evangelist chose these cases rather than others, and that this gives us the impression that demonic possession was almost commonplace; or else many of the things that we would ascribe to disease were ascribed to diabolic influence in a non-scientific age. This last explanation is a popular one: what they called demonic possession then is what we would now call epilepsy, or some form of psychosis.

This last is a tempting theory, though it would suggest diseases like epilepsy to have been more common than they are at present. The late Fr Gabriele Amorth, who knew more about the devil than anyone else, estimated that very few of the troubled people who came to see him were actually possessed by the devil. At the same time he was absolutely convinced that diabolical possession was real. To deny the reality of diabolical possession would be to make certain aspects of the Gospel teaching very hard to grasp. The ministry of Jesus would lose some of its import if we were to dismiss diabolical possession as illusory.

It is 45 years since he made The Exorcist, one of the greatest movies of all time, but the film’s director, William Friedkin, has made several pertinent observations on this very question, and he comes down, essentially, in favour of the Amorth position. Diabolical possession is real. One can read a report of his remarks here.

The conclusion would seem to be that diabolical possession is a religious phenomenon for which science has no convincing explanation, or at least not yet, as some might want to observe. Perhaps new discoveries may help us to understand the phenomenon better in future; but it is also possible that new discoveries may simply deepen the mystery. I would not go so far as to say that these cases that leave doctors baffled somehow or another prove the existence of God. That would be crass. But they do prove the limits of science, which is not an all-embracing explanation for everything, or so it seems to me.

A.N. Wilson, the novelist and contributor to this magazine from time to time, has written a novel, Resolution (reviewed in this magazine by the present writer), which makes precisely this point. The hero of the novel is a man who really lived called Georg Forster and whose life, though relatively short, spanned the glories and the depravity of the Enlightenment. A scientist, a traveller, a recorder of phenomena, Forster nevertheless lived to take part in the French Revolution as a dedicated Jacobin, and, as the novel makes clear, lived to see just where the pursuit of pure reason led. Overturning throne and altar might sound very logical, but once you do so, you destroy so much of human life. The human race lives at so many levels apart from that of the mind.

And that of course brings us back to the extraordinary and haunting success of The Exorcist, both as book and movie. There are phenomena that lie beyond easy explanation – science does not have all the answers. Human experience is not reducible to purely scientific explanation. The enduring popularity of The Exorcist, and our fascination with the occult in general, are not merely reducible to superstition, but tell us something real about our own nature, namely that there is so much of it that transcends our understanding.