Five charges against the precautionary principle

We defend the precautionary principle against five common charges, namely that it is ill-defined, absolutist, and a value judgement, increases risk-taking, and marginalizes science. We argue, first, that the precautionary principle is, in principle, no more vague or ill-defined than other decision principles and like them it can be made precise through elaboration and practice. Second, the precautionary principle need not be absolutist in the way that has been claimed. A way to avoid this is through combining the precautionary principle with a specification of the degree of scientific evidence required to trigger precaution, and/or with some version of the de minimis rule. Third, the precautionary principle does not lead to increased risk-taking, unless the framing is too narrow, and then the same problem applies to other decision rules as well. Fourth, the precautionary principle is indeed value-based, but only to the same extent as other decision rules. Fifth and last, the precautionary principle is not unscientific other than in the weak sense of not being exclusively based on science. In that sense all decision rules are unscientific.