Pius XII, Optatissima Pax (1947)
And the Power(lessness) of Prayer

It was on this date, December 18, 1947, that Pope Pius XII, in the ninth year of his papacy, promulgated the encyclical Optatissima Pax, On Prescribing Prayers for Peace. This was timed well, for World War Two had ended just two years earlier. And Pius was the same pope, born Eugenio Pacelli, whose tepid and infrequent condemnations of Hitler and the Nazis, while somewhat successful, only show that had he condemned the atrocities more forcefully and more frequently, millions of Jewish lives could have been saved.

But perhaps Pius thought prayer might be more effective than action? Optatissima Pax is not one of his greatest encyclicals, but in it Pius blames World War Two on a turning away from Christ. He enjoins "all Our children in Christ to storm heaven with more fervent prayers..." He reminds his flocks that "the flood of evil and disaster that has over-taken the world in past years was due chiefly to the fact that the divine religion of Jesus Christ ... did not govern, as it should, private, domestic and public life." He lays out a vision of Jesus in the manger at Christmastime and urges "united prayer, imploring peace, harmony and mutual charity."

As it is commonly understood, praying is asking a supernatural being to cause things to happen in the natural world that would not happen naturally. For prayer to work, God would have to be both perfect and imperfect at the same time. If God is perfect, then any plea for intercession could not possibly change his actions. As Epicurus (and even Mary Baker Eddy) once asked, how does one change perfection?

If God could change nature at will, then the order and regularity of the world that science attempts to explain would be impossible. Science would be pointless. And, if you think about it, so would human law: God could cause people to act contrary to their will (that is, involuntarily). Law would be pointless if God could change a person's behavior. In fact, if prayer worked at all, we would have to abandon our trust in our senses, the very senses, one would suppose, that God gave us in order to survive in the world!

As it happens, the efficacy of prayer has been studied in the laboratory. The most famous, if not the oldest, scientific study was that of the pioneer eugenicist, Francis Galton, in 1872: Statistical Inquiries Into the Efficacy of Prayer. His conclusion? No correlation between prayer and any measurable effect on the natural world. There have been a number of studies since: serious studies that found either no positive correlation between prayer and beneficial medical outcomes, or the correlation was statistically insignificant. In the cases where the correlation could not be explained by chance, it could easily be explained by methodological flaws in the research.

As "The Straight Dope" put it in November 2000:

In summary, we have no good evidence of the effectiveness of intercessory prayer in which the person does not know he is being prayed for. Those who believe prayer will help them and know they are being prayed for may indeed get better, thanks to the placebo effect. The same could be said of giving pets to the elderly who like animals (which research has shown is related to both physical and psychological improvement). However, as Matthews, Conti, and Christ note, "if a patient did not like cats, for example, it would seem inadvisable to put one on an elderly lap." Similarly, "the current research does not suggest that atheists facing heart surgery should be told by their physicians to start praying."*

So we might take the advice of Pius XII in Optatissima Pax — but then we risk praying to the wrong god!

* Quoted from "The Straight Dope," 2 November 2000; the Matthews-Conti-Christ quotes are from "God's HMO: Prayer, Faith, Belief & Physical Well-Being," in Skeptic magazine, vol. 8, no. 2. Other skeptical looks at prayer studies can be found in: Irwin Tessman and Jack Tessman, "Efficacy of Prayer: A Critical Examination of Claims," Skeptical Inquirer, March/April 2000 and Gary Posner, M.D., Free Inquiry magazine, Spring 1990.

Originally published December 2003.