Enthusiasts of so-called alternative medicine (SCAM) sometimes remind me of the French philosopher, Blaire Pascal, and his famous wager. Blaise Pascal (1623-1662) argued that, because it is impossible to either prove or disprove the existence of God, it would probably be best to wager in favor of his existence. In case one got it wrong, little would be lost; in case one was correct, everything was gained.

Likewise, enthusiasts of SCAM often argue that, because of the lack of evidence for many SCAMs, one cannot be sure whether they work or not. Thus it would probably be best to wager in favor of SCAM and make use of it. In case one got it wrong, little would be lost; in case one was correct, everything was gained.

This line of thinking is common and, at first glance, it seems to be “a safe bet”. However, once we analyze it critically, it quickly falls apart. To explain, it might be best to choose a concrete example. Let’s assume, therefore, that we are talking about a cancer patient who wants to leave no stone unturned to cure her cancer.

So, she goes on the Internet and does her ‘research’. As soon as she has found a SCAM that might suit her, another one crops up, and then another, and then dozens. Which SCAM should she use? There are hundreds of SCAM cancer “cures” being promoted to the unsuspecting and vulnerable. Since one is as unproven as the next, our patient has a hard time deciding which SCAM to try. Applying all simultaneously or consecutively would be “betting on the safe side,” but is not a realistic option. If nothing else, it would be an unaffordable full-time job.

A further flaw in Pascal’s approach to SCAM relates to the fact that we are unable to prove the existence of God, but scientists are entirely capable of finding out about SCAM and its effects on cancer patients. After all, that’s what clinical trials are designed for. If for a particular SCAM, no studies are available (which is often the case), it probably means that it is not worth the effort of testing the claims that are being made for it. SCAM cancer cures are ‘alternatives’ for one main reason: they are implausible, so much so that the chances of them doing more good than harm usually approach zero.

And there is yet another caveat: while accepting the existence of God might be not associated with major harm (I know, some people would dispute this), many SCAMs are by no means free of risks. Therefore it is simply not true to assume that “little is lost” in case they do not work.

Direct harm can occur through the interactions of some form of SCAM with prescription drugs, for instance. But the potential for indirect harm is much more important. Here the risks range from raising false hopes or financial exploitation to undermining rationality in a much more general sense. By far the biggest indirect risk is that SCAM is used as a replacement for effective treatments. Most patients do not approach SCAM to give up conventional medicine entirely. But SCAM practitioners can be most persuasive, and some over-enthusiastic SCAM therapists do try to convince their patients to abandon life-saving treatments.

Pascal’s wager was disputed when it was first published. As a result of the ensuing discussions, significant advances were made, for instance, in the area of probability theory. Applying Pascal’s wager to SCAM, as many enthusiasts do, is however a very different matter. I am afraid, the benefits of doing so might not outweigh the risks.

6 Responses to Pascal’s wager applied to so-called alternative medicine

  • I found the following helpful while battling with Pascal’s wager, and the issues raised in Edzard’s post. I hope that it may be useful to some of the readers.

    If God is intervening into our world, he must be doing so in some measurable way. That’s what we do with science. We measure.
    — Michael Shermer (2006)

  • As discussed Pascal’s wager in it’s original form is not applicable to SCAM. Perhaps a modified version of it might be considered by SCAM proponents?

    A person is considering jump off a steep cliff and prays to God to swoop in and save them from imminent death. Should this person still wager in favor of his existence?

    • @Talker

      According to a jump if a cliff, I would suggest a randomised controlled trial, following a parachute jump of a airplane compared without parachute, as was published here

      • Parachute use compared with a backpack control did not reduce death or major traumatic injury when used by participants jumping from aircraft in this first randomized evaluation of the intervention. This largely resulted from our ability to only recruit participants jumping from stationary aircraft on the ground. When beliefs regarding the effectiveness of an intervention exist in the community, randomized trials evaluating their effectiveness could selectively enroll individuals with a lower likelihood of benefit, thereby diminishing the applicability of trial results to routine practice. Therefore, although we can confidently recommend that individuals jumping from small stationary aircraft on the ground do not require parachutes, individual judgment should be exercised when applying these findings at higher altitudes.


        Thanks for sharing the article. It is hilarious!

  • I’m a retired Prof of Surgery who was director of the CRUK clinical trials centre until about 15 years ago. My group ran the successful trials for tamoxifen and aromatase inhibitors that contributed to a 30% reduction in breast cancer mortality in the UK. At that time I thought it might be interesting to check the world wide web to see the number of references to our scientific work, with Iscador (homeopathic doses of extract of mistletoe) top of the pops for SCAM treatment for breast cancer. I found about 20,000 references to the “golden bough” and only about 2,000 references to adjuvant endocrine therapy. QED

  • “Direct harm can occur through the interactions of some form of SCAM with prescription drugs, for instance. But the potential for indirect harm is much more important”

    For funny comparisons, Ernst in the infamous paper found only 4 deaths associated to homeopathy. And ridiculous, the man that reject any positive evidence caused by homeopathy high dilutions, in his paper says that some deadly or injured cases were caused by high potencies! How Ernst can manage this contradition?

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