Wednesday, 30 March 2011
Robust Decision Making and the Dilemma Objection to the Precautionary Principle
Daniel Steel, CPS ‘02, Michigan State University
4:30 pm, 1500 Wesley W. Posvar Hall

Abstract:  Since the 1980s, the Precautionary Principle (PP) has become an increasingly prevalent element of international environmental policy agreements, yet a vigorous debate continues about just what PP is and whether it is reasonable. Perhaps the most commonly voiced objection to PP takes the form of a dilemma: depending on how the principle is interpreted, it is either incoherent or trivial. Critics who pose this dilemma to PP typically suggest some version of cost-benefit analysis (CBA) as a preferable alternative. In this essay, I defend an interpretation of PP that shows how it is a non-trivial and plausible alternative to CBA for evaluating environmental policies. I suggest that PP diverges from CBA in three fundamental ways. First, CBA assumes that all values associated with outcomes should be represented on a common numerical scale, which is typically taken to be monetary, an assumption known as value commensurability. In contrast, PP rejects value commensurability. Secondly, CBA requires a probability distribution that is complete in the sense of assigning an informative probability estimate to all possible outcomes. This conflicts with a core theme of PP that the lack of firmly established informative quantitative estimates of the probabilities of harm is not a prerequisite for action. Finally, PP emphasizes the active search for better alternative policy options while cost benefit analysis compares a set of predetermined options and includes no procedure for generating new alternative policies. I argue that these three features of PP—along with several other themes commonly associated with it, including, pre-market testing, alternatives analysis, and an emphasis on greater public participation—can be explained by a Robust Decision Making (RDM) approach to evaluating environmental policies.