How Change Happens

by Cass R Sunstein

  Above all, I urge that such regulators should use a wide rather than narrow viewscreen—and that, as applied, the precautionary principle is defective precisely because it runs afoul of this idea. To be sure, many of those who endorse the principle seek to protect against neglect of the future, disregard of the interests of those suffering from the greatest deprivation, indifference to catastrophic or worst-case scenarios, and impossible demands for unambiguous evidence from regulators. But as we shall see, the precautionary principle is a crude and sometimes perverse way of promoting those goals, which can be obtained through other, better routes.

  Definitions

  For those interested in precautions, the initial question is this: what exactly does the precautionary principle mean or require? We can imagine a continuum of understandings. At one extreme are weak versions to which no reasonable person could object. At the other extreme are strong versions that would require a fundamental rethinking of regulatory policy.

  The most cautious and weak versions suggest, quite sensibly, that a lack of decisive evidence of harm should not be a ground for refusing to protect against risks. Controls might be justified even if we cannot establish a definite connection between, for example, low-level exposures to carcinogens and adverse effects on human health. Thus the 1992 Rio Declaration states, “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.”

  The Ministerial Declaration of the Second International Conference on the Protection of the North Sea, held in London in 1987, is in the same vein: “Accepting that in order to protect the North Sea from possibly damaging effects of the most dangerous substances, a Precautionary Principle is necessary which may require action to control inputs of such substances even before a causal link has been established by absolutely clear scientific evidence.” Similarly, the United Nations Framework Convention on Climate Change offers cautious language: “Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing [regulatory] measures, taking into account that policies and measures to deal with climate change should be cost-effective so as to ensure global benefits at the lowest possible cost.”

  The widely publicized Wingspread Declaration, from a meeting of environmentalists in 1998, goes further: “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.” The first sentence just quoted is a mildly more aggressive version of the statement from the Rio Declaration. It is more aggressive because it is not limited to threats of serious or irreversible damage. But in reversing the burden of proof, the second sentence goes further still. (Everything depends, of course, on what those with the burden of proof are required to show.)

  In Europe, the precautionary principle has sometimes been understood in a still stronger way, asking for a significant margin of safety for all decisions. According to one definition, the precautionary principle means “that action should be taken to correct a problem as soon as there is evidence that harm may occur, not after the harm has already occurred.”2 The word may is the crucial one; almost all of the time, there will be “evidence that harm may occur,” if may is not understood to require some threshold of probability. In a comparably strong version, the Final Declaration of the First European “Seas at Risk” conference says that if “the ‘worst case scenario’ for a certain activity is serious enough then even a small amount of doubt as to the safety of that activity is sufficient to stop it taking place.”3

  The weak versions of the precautionary principle state a truism—uncontroversial in principle and necessary in practice only to combat public confusion or the self-interested claims of private groups demanding unambiguous evidence of harm (which no rational society requires). The weakest versions may be important in practice, but in principle they are unobjectionable, even banal; for that reason, I will not discuss them here. To make analytic progress, let us understand the principle in a strong way, to suggest that regulation is required whenever there is a potential risk to health, safety, or nature, even if the supporting evidence remains speculative and even if the economic costs of regulation are high. To avoid palpable absurdity, the idea of potential risk will be understood to require a certain threshold of scientific plausibility. To support regulation, no one thinks that it is enough if someone, somewhere, urges that a risk is worth taking seriously. But under the precautionary principle as I shall understand it, the threshold burden is minimal—and once it is met, there is something like a presumption in favor of regulatory controls.

  I believe that this understanding of the precautionary principle fits with the understandings of some of its most enthusiastic proponents, and that with relatively modest variations, it fits with many of the legal formulations as well.

  Self-Contradiction and Paralysis

  It is tempting to object that the precautionary principle, thus understood, is hopelessly vague. How much precaution is the right amount of precaution? By itself, the principle does not tell us. It is also tempting to object that the principle is, but should not be, cost blind. Some precautions simply are not worthwhile, because they cost so much and help so little. But the most serious problem lies elsewhere. The real problem is that the principle offers no guidance—not that it is wrong, but that it forbids all courses of action, including regulation. It bans the very steps that it requires.

  To understand the objection, it will be useful to anchor the discussion in some concrete problems:

  Genetic modification of food has become a widespread practice.4 The risks of that practice are not known with precision. Some people fear that genetic modification will result in serious ecological harm; others believe that the risks are vanishingly low, and that genetic modification will result in more nutritious food and significant improvements in human health.

  Many people fear nuclear power on the ground that nuclear power plants create various health and safety risks, including some possibility of catastrophe. But if a nation does not rely on nuclear power, it might well rely instead on fossil fuels and in particular on coal-fired power plants. Such plants create risks of their own, including risks associated with climate change. At some points in recent history, China has relied on nuclear energy in a way that reduces greenhouse gases and a range of air pollution problems.5

  There is a possible conflict between the protection of marine mammals and military exercises. The United States Navy engages in many such exercises, and it is possible that marine mammals will be threatened as a result. Military activities in the oceans might well cause significant harm, but a decision to suspend those activities might also endanger military preparedness (or so the government contends).6

  In these cases, what kind of guidance is provided by the precautionary principle? It is tempting to say that the principle calls for strong regulatory controls. In all of these cases, there is a possibility of serious harm, and no authoritative scientific evidence demonstrates that the possibility is zero. Put to one side the question of whether the precautionary principle, understood to compel stringent regulation in these cases, is sensible. Let us ask a more fundamental question: Is more stringent regulation therefore compelled by the precautionary principle?

  The answer is that it is not. In some of these cases, it should be easy to see that in its own way, stringent regulation would actually run afoul of the precautionary principle. The simplest reason is that such regulation might well deprive society of significant benefits and hence produce many deaths that would otherwise not occur. In some cases, regulation eliminates the opportunity benefits of a process or activity and thus causes preventable deaths. If this is so, regulation is hardly precautionary.

  Consider the case of gen
etic modification of food. Many people object to genetic modification, with the thought that “tampering with nature” can produce a range of adverse consequences for the environment (and also for human health). But many other people believe not only that these fears are baseless but also that a failure to allow genetic modification might well result in numerous deaths and a small probability of many more. The reason is that genetic modification holds the promise of producing food that is both cheaper and healthier—resulting, for example, in golden rice, which might have large benefits in developing countries. The point is not that genetic modification will definitely have those benefits or that the benefits of genetic modification outweigh the risks. The claim is only that if the precautionary principle is taken literally, it is offended by regulation as well as by nonregulation.

  Regulation sometimes violates the precautionary principle because it would give rise to substitute risks, in the form of hazards that materialize or are increased as a result of regulation. Consider the case of DDT, often banned or regulated in the interest of reducing risks to birds and human beings. The risk with such bans is that in poor nations, they may eliminate what appears to be the most effective way of combating malaria—and thus significantly undermine public health.

  Or consider the so-called drug lag, produced whenever the government takes a highly precautionary approach to the introduction of new medicines and drugs into the market. If a government insists on such an approach, it will protect people against harms from inadequately tested drugs—but it will also prevent people from receiving potential benefits from those very drugs. Is it precautionary to require extensive premarketing testing or to do the opposite? In the context of medicines to prevent AIDS, those who favor precautions have asked governments to reduce premarketing testing, precisely in the interest of health. The United States, by the way, is more precautionary about new medicines than are most European nations—but by failing to allow such medicines on the market, the United States fails to take precautions against the illnesses that could be reduced by speedier procedures. More generally, a sensible government might want to ignore the small risks associated with low levels of radiation on the ground that precautionary responses are likely to cause fear that outweighs any health benefits from those responses.

  We should now be able to see the sense in which the precautionary principle, taken for all that it is worth, is paralyzing: it stands as an obstacle to regulation and nonregulation and everything in between. But these points simply raise an additional question: Why is the precautionary principle so influential? Why does it speak to so many people? I suggest that the principle becomes operational if and only if those who apply it wear blinders—only, that is, if they focus on some aspects of the regulatory situation but downplay or disregard others. But that suggestion raises further questions. What accounts for the particular blinders that underlie applications of the precautionary principle? When people’s attention is selective, why is it selective in the way that it is?

  The Mythical Benevolence of Nature

  Sometimes the precautionary principle operates by incorporating the belief that nature is essentially benign and that human intervention is likely to carry risks—as in the suggestion that the precautionary principle calls for stringent regulation of pesticides or genetically modified organisms. Many people fear that any human intervention will create losses from the status quo and that these losses should carry great weight, whereas the gains should be regarded with some skepticism or at least be taken as less weighty. For example, “human intervention seems to be an amplifier in judgments on food riskiness and contamination,” even though “more lives are lost to natural than to man-made disasters in the world.”7 Studies show that people overestimate the carcinogenic risk from pesticides and underestimate the risks of natural carcinogens. People also believe that nature implies safety, so much so that they will prefer natural water to processed water even if the two are chemically identical.8

  A belief in the benevolence of nature plays a major role in the operation of the precautionary principle, especially among those who see nature as harmonious or in balance. In fact, many of those who endorse the principle seem to be especially concerned about new technologies. Most people believe that natural chemicals are safer than man-made chemicals.9 (Most toxicologists disagree.) On this view, the principle calls for caution when people are intervening in the natural world. Here we can find some sense: nature often consists of systems, and interventions into systems can cause serious problems. But there is a large problem with this understanding of the precautionary principle: what is natural may not be safe at all.10

  Consider in this light the familiar idea that there is a “balance of nature.” According to a fairly standard account, this idea is “not true.”11 Nature “is characterized by change, not constancy,” and “natural ecological systems are dynamic,” with desirable changes often being “those induced through human action.”12 In any case, nature is often a realm of destruction, illness, killing, and death. Hence the claim cannot be that human activity is necessarily or systematically more destructive than nature. Nor is it clear that natural products are comparatively safe.13 Organic foods, favored by many people on grounds of safety and health and creating annual revenues of $4.5 billion in the United States alone, have many virtues, but it is not clear that they are healthier to eat. According to an admittedly controversial account, they are “actually riskier to consume than food grown with synthetic chemicals.”14 If the precautionary principle is seen to raise serious doubts about pesticides but never about organic foods, it may be because the health risks that come with departures from nature register as especially troublesome.

  Some of the most serious risks we face are a product of nature. Nothing is more natural than exposure to sunlight, which many people do not fear. But such exposure is associated with skin cancer and other serious harms. Tobacco smoking kills more than four hundred thousand Americans each year, even though tobacco is a product of nature. To say all this is not to resolve specific issues, which depend on complex questions of value and fact. But a false belief in the benevolence of nature helps to explain why the precautionary principle is thought, quite incorrectly, to provide a great deal of analytical help.

  Loss Aversion

  People tend to be loss averse, which means that a loss from the status quo is seen as more undesirable than a gain is seen as desirable.15 When we anticipate a loss of what we now have, we can become genuinely afraid, in a way that greatly exceeds our feelings of pleasure when we anticipate some supplement to what we now have. So far, perhaps, so good. The problem comes when individual and social decisions downplay potential gains from the status quo and fixate on potential losses, in such a way as to produce overall increases in risks and overall decreases in well-being.

  In the context of risk regulation, there is a clear implication: people will be closely attuned to the losses produced by any newly introduced risk, or by any aggravation of existing risks, but far less concerned with the foregone benefits that result from regulation. Loss aversion often helps to explain what makes the precautionary principle operational. The opportunity costs of regulation often register little or not at all, whereas the out-of-pocket costs of the activity or substance in question are entirely visible. In fact this is a form of status quo bias. The status quo marks the baseline against which gains and losses are measured, and a loss from the status quo seems much worse than a gain from the status quo seems good.

  If loss aversion is at work, we would predict that the precautionary principle would place a spotlight on the losses introduced by some risk and downplay the foregone benefits resulting from controls on that risk. Recall the emphasis, in the United States, on the risks of insufficient testing of medicines as compared with the risks of delaying the availability of those medicines. If the opportunity benefits are offscreen, the precautionary principle will appear to give guidance, notwithstanding the objections I have made. At the same time, the neglected opportunity
benefits sometimes present a devastating problem with the use of the precautionary principle. In the context of potential life-saving drugs, this is very much the situation.

  Loss aversion is closely associated with another cognitive finding: people are far more willing to tolerate familiar risks than unfamiliar ones, even if they are statistically equivalent.16 For example, the risks associated with driving often do not occasion a great deal of concern, even though in the United States alone, tens of thousands of people die from motor vehicle accidents each year. The relevant risks are seen as part of life. By contrast, many people are quite concerned about risks that appear newer, such as the risks associated with genetically modified foods, recently introduced chemicals, and terrorism. Part of the reason for the difference may be a belief that with new risks, we are in the domain of uncertainty (meaning that we cannot assign probabilities to bad outcomes) rather than risk (where probabilities can be assigned), and perhaps it makes sense to be cautious when we are not able to measure probabilities. But the individual and social propensity to focus on new risks outruns that sensible propensity. It makes the precautionary principle operational by emphasizing, for no good reason, a mere subset of the hazards involved.