Document Type

Working Paper

Repository Date



Precautionary Principle, Cost Benefit Analysis, Regulation, Climate Change, Nanotechnology

Subject Categories

Administrative Law | Environmental Law | Intellectual Property Law | Law | Property Law and Real Estate | Torts


This article defines the precautionary principle (PP) primarily based on what it is not: it is not quantitative cost-benefit analysis (CBA) or cost-cost analysis of the sort we associate with the Office of Management and Budget in the United States and U.S. policymaking and policy discourse generally. In this definition, the PP is a form of analysis in which the costs of a possible environmental or health risk are not quantified, or if they are, any quantification is likely to be inadequate to capture the full extent of the costs of not taking regulatory measures to mitigate or avoid the risk. So defined, the PP is a more "rational" approach compared to cost-benefit or cost-cost because, in certain contexts, the costs associated with an environmental or health risk will tend to be relatively under-weighed without the application of the PP to account for non-quantifiable risk.

In both the cases of climate change and emerging technologies such as nanotechnology, application of the PP can correct what would otherwise be a tendency to under-weigh the costs of not taking action to prevent or mitigate possible environmental and health risks. The PP can justify directing less attention to "bottom line" quantitative estimates of the costs of unmitigated climate change and more attention to avoiding terrible but highly uncertain climate change scenarios. With nanotechnology, the PP can function as a means of focusing less attention on whether or not nanotechnology is harmful or safe given current knowledge and more attention to developing ways to produce more and better knowledge about the risks posed by nanotechnology. The debate over the PP versus CBA has often been too abstract and lacking in context. A more productive approach would be to instead ask when ¬ in what contexts — does it make sense to apply the PP and when does it not? This article is an initial contribution to that re-framed debate.