RT Journal Article SR Electronic T1 Should the precautionary principle guide our actions or our beliefs? JF Journal of Medical Ethics JO J Med Ethics FD BMJ Publishing Group Ltd and Institute of Medical Ethics SP 5 OP 10 DO 10.1136/jme.2005.015495 VO 33 IS 1 A1 Peterson, M YR 2007 UL http://jme.bmj.com/content/33/1/5.abstract AB Two interpretations of the precautionary principle are considered. According to the normative (action-guiding) interpretation, the precautionary principle should be characterised in terms of what it urges doctors and other decision makers to do. According to the epistemic (belief-guiding) interpretation, the precautionary principle should be characterised in terms of what it urges us to believe. This paper recommends against the use of the precautionary principle as a decision rule in medical decision making, based on an impossibility theorem presented in Peterson (2005). However, the main point of the paper is an argument to the effect that decision theoretical problems associated with the precautionary principle can be overcome by paying greater attention to its epistemic dimension. Three epistemic principles inherent in a precautionary approach to medical risk analysis are characterised and defended.