, Volume 194, Issue 4, pp 1363–1396 | Cite as

The relativity of ‘placebos’: defending a modified version of Grünbaum’s definition

  • Jeremy HowickEmail author


Debates about the ethics and effects of placebos and whether ‘placebos’ in clinical trials of complex treatments such as acupuncture are adequate (and hence whether acupuncture is ‘truly’ effective or a ‘mere placebo’) rage. Yet there is currently no widely accepted definition of the ‘placebo’. A definition of the placebo is likely to inform these controversies. Grünbaum’s (1981, 1986) characterization of placebos and placebo effects has been touted by some authors as the best attempt thus far, but has not won widespread acceptance largely because Grünbaum failed to specify what he means by a therapeutic theory and because he does not stipulate a special role for expectation effects. Grünbaum claims that placebos are treatments whose ‘characteristic features’ do not have therapeutic effects on the target disorder. I show that with four modifications, Grünbaum’s definition provides a defensible account of placebos for the purpose of constructing placebo controls within clinical trials. The modifications I introduce are: adding a special role for expectations, insisting that placebo controls control for all and only the effects of the incidental treatment features, relativizing the definition of placebos to patients, and introducing harmful interventions and nocebos to the definitional scheme. I also provide guidance for classifying treatment features as characteristic or incidental.


Philosophy of science Methodology Placebo Randomized trial Grünbaum Philosophy of medicine Ethics 



Special thanks to my Ph.D. supervisor John Worrall, with whom this paper was developed. Most of the ideas and much of the writing of the first two sections of the paper is John’s. Thanks also to Nancy Cartwright and Michael Hardimon who both commented on earlier drafts of this paper, to Sir Iain Chalmers for insisting that I use real examples wherever possible, to the University of California at San Diego Graduate Conference attendees (organized by Michael Hardimon), to attendees of the “Evidence in Science and Epistemology” conference in Helsinki (especially Maria Lasonen-Aarnio, Petri Ylikoski, and Markus Lammenranta), to Have Carel and Alexander Bird for hosting me to give a talk about this paper at the University of Bristol and for providing useful comments. Andrew Turner, Frank Miller, and Wiebe Van Der Hoek gave useful feedback on earlier versions of the manuscript. Students taking part in the Oxford Philosophy of Medicine Seminar Series at All Souls, Oxford, including Matthew Clark, Meghana Mishra provided useful insights.

Funding information

This work was partly supported by the National Institute for Health Research School for Primary Care Research (NIHR SPCR). The views expressed are those of the author and not necessarily those of the NHS, the NIHR or the Department of Health.


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Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.Nuffield Department of Primary Care Health SciencesUniversity of OxfordOxfordUK

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