A prima facie argument in favour of the efficacy of prayer is […] to be drawn from the very general use of it. The greater part of mankind, during all the historic ages, has been accustomed to pray for temporal advantages. How vain, it may be urged, must be the reasoning that ventures to oppose this mighty consensus of belief! Not so. The argument of universality either proves too much, or else it is suicidal. It either compels us to admit that the prayers of Pagans, of Fetish worshippers and of Buddhists who turn praying wheels, are recompensed in the same way as those of orthodox believers; or else the general consensus proves that it has no better foundation than the universal tendency of man to gross credulity.

Francis Galton, ‘Statistical Inquiries into the Efficacy of Prayer’, Fortnightly Review, vol. 12, no. 68 (August, 1872), pp. 125–135