Some years ago I got up one morning intending to have my hair cut in preparation for a visit to London, and the first letter I opened made it clear I need not go to London. So I decided to put the haircut off too. But then there began the most unaccountable little nagging in my mind, almost like a voice saying, “Get it cut all the same. Go and get it cut.” In the end I could stand it no longer. I went.
Now my barber at that time was a fellow Christian and a man of many troubles whom my brother and I had sometimes been able to help. The moment I opened his shop door he said, “Oh, I was praying you might come today.” And, in fact, if I had come a day or so later, I should have been of no use to him. It awed me; it awes me still. But, of course, one cannot rigorously prove a causal connection between the barber’s prayers and my visit. It might be telepathy. It might be accident.
I have stood by the bedside of a woman whose thighbone was eaten through with cancer and who had thriving colonies of the disease in many other bones as well. It took three people to move her in bed. The doctors predicted a few months of life; the nurses (who often know better), a few weeks. A good man laid his hands on her and prayed. A year later the patient was walking (uphill, too, through rough woodland) and the man who took the last X-ray photos was saying, “These bones are as solid as rock. It’s miraculous.” But once again there is no rigorous proof. Medicine, as all true doctors admit, is not an exact science. We need not invoke the supernatural to explain the falsification of its prophecies. You need not, unless you choose, believe in a causal connection between the prayers and the recovery.
The question then arises, “What sort of evidence would prove the efficacy of prayer?” The thing we pray for may happen, but how can you ever know it was not going to happen anyway? Even if the thing were indisputably miraculous, it would not follow that the miracle had occurred because of yqur prayers. The answer surely is that a compulsive empirical proof such as we have in the sciences can never be attained.
Some things are proved by the unbroken uniformity of our experiences. The law of gravitation is established by the fact that, in our experience, all bodies without exception obey it. Now even if all the things that people prayed for happened, which they do not, this would not prove what Christians mean by the efficacy of prayer. For prayer is request. The essence of request, as distinct from compulsion, is that it may or may not be granted.
—The World’s Last Night