I've therefore become quite a connoisseur of airport chapels, or rather, of the rooms usually called something like an interfaith facility for quiet meditation . . .

rooms decorated in a way that vaguely invokes the chapel, though they're at the very end of the traditions of decoration that were once reserved to the sacred.

There's always pale wood, these days, and a little bit of coloured, if not stained, glass, and in Kennedy the seats of the chairs are woven of a kind of straw in a gesture, I suppose, towards the antique, and the virtue of simplicity. I remember ticking off in . . . I think it was Ronald Reagan Airport in Washington DC . . . the list of symbols which airport chapel designers have decided are pious without being ideological. A fish, a bird, a lamb. Images can't be more specific . . .

crosses, for example, are in very short supply, since various denominations and sects must share the space.

But even in the chapels that most closely resemble the foyers of bleak motels, the air has, to my mind, a quality of stillness. Even if the reason you're in the chapel is that you're trying to get away from other people . . . even if you're doing nothing more spiritual than sitting there thinking bad thoughts about Aer Lingus . . . you can feel that particular stillness.

And what has the air been made still by, if not by prayer? The least rooms, as much as the greatest buildings, in which many people have sincerely addressed themselves in silence to a silent deity, retain something of the extraordinariness of that act. They are more dense than ordinary places.

I begin to think upwards, in chapels, as if I'm addressing an above place or being. And I notice that I am conditioned, when I'm thinking upwards, to implore.

Once I tilt towards that trajectory, a crowd begins to jostle into my mind.

This person has been drinking harder than ever now he's been fired, that one's teenager's wildness is wrecking the family, this old friend never returns phone calls any more, that one is devastated by a partner's infidelity. Not to even begin on the starving children with flies in their eyes or the women raped over and over in the course of war and aggression or the men lost to the protections of society in secret jails, or the poor of the earth . . . men working in terrible mines, in quarries, children scavenging garbage heaps, cleaning women plodding through cold streets at dawn. But a strangled, hopeless wish that things might be other than they are . . . is that prayer?

If I say a proper prayer, in the words I remember from childhood (earnestly trying to direct them away from myself), it will be for someone who's sick. When there's nothing else to do and something must be done, it seems natural to pray for the sick. I never gave doing it a second thought, even though I don't know who or what I'm praying to, until I read about the $2.4m experiment, sponsored by the highly respected Templeton Foundation, which recently compared how well cardiac patients who were prayed for recovered, compared to cardiac patients who were not prayed for.

The prayed-for, it turned out, did, if anything, worse than the unprayed-for. This result brought out an amusing variety of clerical defenses. It was because the praying people didn't know the people they were praying for, one chaplain said: personal prayers might be stronger. It would be bad for us, another priest said, if our prayers worked . . . prayers would be "a kind of commercial enterprise". Now he tells us.

But what surprised me was that modern people . . . reputable scientists . . . had ever believed that the effect of prayer could be measured. I think prayer is what you do when concern impels you to act on another person's situation, even though you know you have crossed the threshold into a situation where you have no personal agency.

Prayer is how you signal that you know you have entered the dimension where fate hovers over a person, maybe to go this way, maybe that . . . a dimension where there are no measures, no causes, no effects and which is no more susceptible to scientific enquiry than prayer is to linguistic analysis.

That's how it seems to me. Prayer for the sick. I think, is all the more a loving act within the human community because it is an acknowledgement of powerlessness, not because it is powerful. The scientists were looking the wrong way. If prayer never does the sick or dying good, surely it always does the people who pray good? Doesn't it release them from the prison of the ego by making them move out of themselves towards imagining what it is like to be another person? Doesn't it acknowledge mystery? This doesn't apply to all prayer.

Praying that a delay to a flight will end doesn't count . . . that's just superstition, not that I have anything against superstition.

But to send out frail words in the hope of affecting the great, malign forces of suffering and death . . . no wonder special spaces are put aside to do that in.