Beyond the precautionary principle.

• Author: Sunstein, Cass R.
• Position: Preferences and Rational Choice: New Perspectives and Legal Implications

The precautionary principle has been highly influential in legal systems all over the world. In its strongest and most distinctive forms, the principle imposes a burden of proof on those who create potential risks, and it requires regulation of activities even if it cannot be shown that those activities are likely to produce significant harms. Taken in this strong form, the precautionary principle should be rejected, not because it leads in bad directions, but because it leads in no direction at all. The principle is literally paralyzing--forbidding inaction, stringent regulation, and everything in between. The reason is that in the relevant cases, every step, including inaction, creates a risk to health, the environment, or both. This point raises a further puzzle: Why is the precautionary principle widely seen to offer real guidance ? The answer lies in identifiable cognitive mechanisms emphasized by behavioral economists. In many cases, loss aversion plays a large role, accompanied by a false belief that nature is benign. Sometimes the availability heuristic is at work. Probability neglect plays a role as well. Most often, those who use the precautionary principle fall victim to what might be called "system neglect," which involves a failure to attend to the systemic effects of regulation. Examples are given from numerous areas, involving arsenic regulation, global warming and the Kyoto Protocol, nuclear power, pharmaceutical regulation, cloning, pesticide regulation, and genetic modification of food. The salutary moral and political goals of the precautionary principle should be promoted through other, more effective methods.

INTRODUCTION

All over the world, there is increasing interest in a simple idea for the regulation of risk: In case of doubt, follow the precautionary principle. (1) Avoid steps that will create a risk of harm. Until safety is established, be cautious; do not require unambiguous evidence. In a catchphrase: better safe than sorry. In ordinary life, pleas of this kind seem quite sensible, indeed a part of ordinary human rationality. People buy smoke alarms and insurance. They wear seat belts and motorcycle helmets, even if they are unlikely to be involved in an accident. Shouldn't the same approach be followed by rational regulators as well? Many people believe so. (2)

1. Problems with Precautions

   I aim to challenge the precautionary principle here, not because it leads in bad directions, but because, read for all that it is worth, it leads in no direction at all. The principle threatens to be paralyzing, forbidding regulation, inaction, and every step in between. (3) To explain this problem very briefly, the precautionary principle provides help only if we blind ourselves to many aspects of risk-related situations and focus on a narrow subset of what is at stake. (4) A significant part of my discussion will be devoted to showing why this is so. I will also urge that the precautionary principle gives the (false) appearance of being workable only because of identifiable cognitive mechanisms, which lead people to have a narrow rather than wide viewscreen. With that narrow viewscreen, it is possible to ignore, or to neglect, some of the risks that are actually at stake. I emphasize that we have good reason to endorse the goals that motivate many people to endorse the precautionary principle. These goals include the importance of protecting health and the environment even from remote risks, the need to attend to unintended adverse effects of technological change, and the need to ensure that wealthy countries pay their fair share for environmental improvement and risk reduction. But the precautionary principle is a crude way of protecting these goals, which should be pursued directly. I do not attempt to develop any particular replacement for the precautionary principle, but I do argue on behalf of wide viewscreens in the regulation of risks.

   In making these claims, I will be challenging an idea that is fast becoming a staple of regulatory policy. (5) Indeed, it has been claimed that the precautionary principle has become, or at least is becoming, a binding part of customary international law. (6) In the mid-1970s, German environmental policy was founded on the basis of Vorsorgeprinzip, a precursor of the precautionary principle. (7) With respect to risks, German policy has been described as seeing "precaution" as a highly interventionist idea, one that embodies "a loose and open-ended interpretation of precaution." (8) In the United States, without using the term explicitly, Congress has built a notion of precaution into some important statutes, allowing or requiring regulation on the basis of conservative assumptions. (9) The precautionary principle has played a significant role in international documents, to the point where it has become ubiquitous. Variations on the notion can be found in at least fourteen international documents, (10) In 1982, the United Nations World Charter for Nature apparently gave the first international recognition to the principle, suggesting that when "potential adverse effects are not fully understood, the activities should not proceed." (11) The 1992 Rio Declaration on Environment and Development asserts: "In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation." (12)

   The widely publicized Wingspread Declaration, from a meeting of environmentalists in 1998, goes further still: "When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause-and-effect relationships are not established scientifically. In this context the proponent of the activity, rather than the public, should bear the burden of proof." (13) The European Union treaty states that EU policy on the environment "shall be based on the precautionary principle." (14) In February 2000, the precautionary principle was explicitly adopted by the European Commission, together with implementing guidelines. (15) Notwithstanding official American ambivalence about the principle, (16) there are unmistakable echoes of the principle in American environmental law. (17) The precautionary principle has received a high-profile endorsement in the New York Times Magazine, which listed the principle as one of the most important ideas of 2001. (18)

   In many ways the precautionary principle seems quite sensible, even appealing. (19) To justify regulation, a certainty of harm should not be required; a risk, even a low one, may well be enough. It makes sense to expend resources to prevent a small chance of disaster--consider the high costs, pecuniary and otherwise, that are spent to reduce the risk of terrorist attacks. On reasonable assumptions, these costs are worth incurring even if the probability of harm, in individual cases or even in the aggregate, is relatively low. The precautionary principle might well be seen as a plea for a kind of regulatory insurance. Certainly the principle might do some real-world good, spurring governments to attend to neglected problems. Nonetheless, I will be urging that the principle cannot be fully defended in these ways, simply because risks are on all sides of social situations. Any effort to be universally precautionary will be paralyzing, forbidding every imaginable step, including no step at all.

2. Precautions and Rationality

   But if the precautionary principle, taken in a strong form, is unhelpful, in a way literally senseless, how can we account for its extraordinary influence, and indeed for the widespread belief that it can and should guide regulatory judgments? I have mentioned its possible pragmatic value. And undoubtedly the principle is invoked strategically by self-interested political actors; European farmers, for example, invoke the idea of precaution to stifle American competitors, who are far more likely to rely on genetically modified crops. (20) But apart from this point, I suggest that an understanding of human rationality and cognition provides five useful clues.

   1. Loss Aversion

      The precautionary principle often seems appealing because of loss aversion. The central point here is that people dislike losses far more than they like corresponding gains. (21) The result is that out-of-pocket costs, or deterioration from the status quo, seem much worse than opportunity costs, or benefits lost as a result of continuing the status quo. In the context of risks, people tend to focus on the losses that are associated with some activity or hazard and to disregard the gains that might be associated with that activity or hazard. The precautionary principle often becomes operational only because of loss aversion, as people take precautions against potential losses from the status quo, but neglect potential benefits that would be unmistakable gains. A closely related point is that unfamiliar risks produce far more concern than familiar ones, even if the latter are statistically larger; and the precautionary principle, in practice, is much affected by this fact.

   2. The Myth of a Benevolent Nature

      Loss aversion is often accompanied by a mistaken belief that nature is essentially benign, (22) leading people to think that safety and health are generally at risk only or mostly as a result of human intervention. A belief in the relative safety of nature and the relative risk of new technologies often informs the precautionary principle.

   3. The Availability Heuristic

      It is well known that people focus on some risks simply because they are cognitively "available," whereas other risks are not. (23) When the precautionary principle seems to require stringent controls on one risk, even though other risks are in the vicinity, the availability...