In their article "Experiments on Distant Intercessory Prayer: God, Science, and the Lesson of Massah," Chibnall et al1 conclude that studies of distant, intercessory prayer are unscientific, in part because no known mechanism can be invoked to explain the results. To suggest that the lack of a known mechanism of action should disqualify a topic from scientific investigation is shortsighted and would clearly have inhibited the discovery and use of several highly effective pharmacological or nutritional agents (eg, aspirin, diethylcarbamazine, chloroquine, and even citrus fruits!). One must first establish (using the scientific method) that an intervention produces effects. Once the phenomenon is determined to be real, then the search for mechanisms should begin.
Harris WS, Isley WL. Massah and Mechanisms. Arch Intern Med. 2002;162(12):1420-1423. doi: