Intended for healthcare professionals

Rapid response to:

History And Mystery

Retroactive prayer: a preposterous hypothesis?

BMJ 2003; 327 doi: (Published 18 December 2003) Cite this as: BMJ 2003;327:1465

Rapid Response:

Re: A Scientist's Perspective

Prof Roy characterises my mention of ‘The Force’ as a puerile
reaction. OK, it’s a fair cop. I admit it. It was a bit silly. However,
behind this puerile reaction was a serious point struggling to get out.

As Prof Roy correctly points out, it would be bad science to dismiss
Leibovici’s study out of hand simply because it tests a preposterous
hypothesis. Progress in science is made by being open to seemingly
preposterous hypotheses, and letting experimental evidence be your guide.
Nonetheless, extraordinary claims require extraordinary evidence. I hope
we can all agree that retroactive intercessory prayer represents an
extraordinary claim. Leibovici’s study found no significant effect of
prayer on mortality, and the effects on duration of hospital stay and
duration of fever were of only marginal significance (and duration of stay
would have been non-significant had Leibovici adjusted for multiple
testing). Frankly, this doesn’t even come close to extraordinary evidence.
So I do not dismiss Leibovici’s results purely because they test a
preposterous hypothesis. But because of the combination of preposterous
hypothesis and weak evidence, I cheerfully dismiss them.

But let’s suppose for a minute that someone repeats Leibovici’s
experiment with a larger sample size and finds that the intervention group
fares better on all outcomes with P < 0.00001 for all of them. This
would certainly suggest that all is not well with our current view of the
space-time continuum. But the study would tell us nothing about the
mechanism of the effect. If one is to be guided purely by experimental
evidence, and not by prior religious beliefs, in what way would such a
result be any less evidence for The Force than for the intervention of a
Judaeo-Christian deity?

Competing interests:
OK, I'd better come clean here. I don't actually believe in The Force.

Competing interests: No competing interests

21 January 2004
Adam Jacobs
Dianthus Medical Limited, London SW19 3TZ