The precautionary principle holds that we should not allow scientific uncertainty to prevent us from taking precautionary measures in response to potential threats that are irreversible and potentially disastrous. Critics of the principle claim that it deters progress and development, is excessively risk-aversive and is unscientific. This paper argues that the principle can be scientific provided that the threats addressed by the principle are plausible threats, and the precautionary measures adopted are reasonable. The paper also argues that one may use (...) epistemic criteria, such as consistency, coherence and explanatory power, to determine whether a threat is plausible, and that one may use practical considerations, such as effectiveness, proportionality, cost-effectiveness, realism and consistency, to determine whether a response to a threat is reasonable. (shrink)

“[T]he Precautionary Principle still has neither a commonly accepted definition nor a set of criteria to guide its implementation. “There is”, Freestone … cogently observes, “a certain paradox in the widespread and rapid adoption of the Precautionary Principle”: While it is applauded as a “good thing”, no one is quite sure about what it really means or how it might be..

Research into the mechanisms of aging has suggested the possibility of extending the human life span. But there may be evolutionary biological reasons for senescence and the limits of the cell cycle that explain the infirmities of aging and the eventual demise of all human organisms. Genetic manipulation of the mechanisms of aging could over many generations alter the course of natural selection and shift the majority of deleterious mutations in humans from later to earlier stages of life. This could (...) harm people in the distant future by making them more susceptible to premature disease and mortality. Thus there are biological and moral reasons to carefully consider the implications of exploiting this technology on a broad scale to extend the lives of people in the present and near future. (shrink)

Environmentalists have advocated the Precautionary Principle (PP) to help guide public and private decisions about the environment. By contrast, industry and its spokesmen have opposed this. There is not one principle, but many that have been recommended for this purpose. Despite the attractiveness of a core idea in all versions of the principle—that decision-makers should take some precautionary steps to ensure that threats of serious and irreversible damage to the environment and public health do not materialize into harm—even one of (...) the most widely endorsed principles needs considerable specification and refinement before it can be used. Moreover, the PP is an approach or guide to utilizing scientific evidence in social or legal decision-making contexts. In this it does not differ in kind from other approaches to using factual information such as in the law. The law provides some models for different strategies to guide decision-making under uncertainty when factual issues cannot be resolved with certainty. These in turn can help guide the formulation of different versions of PP and help clarify some presuppositions of the principle. Once some plausible versions of PP are articulated, I suggest some applications to existing environmental problems. (shrink)

Who is right? In Risk and Rationality, Kristin Shrader-Frechette argues that neither charges of irresponsible endangerment nor countercharges of scientific illiteracy frame the issues properly.

The precautionary principle brings a special challenge to the practice of evidence-based public health decision-making, suggesting changes in the interpretative methods of public health used to identify causes of disease. In this paper, precautionary changes to these methods are examined: including discounting contrary evidence, reducing the number of causal criteria, weakening the rules of evidence assigned to the criteria, and altering thresholds for statistical significance. All such changes reflect the precautionary goal of earlier primary preventive intervention, i.e. acting on insufficient (...) evidence, the least amount, or minimum level, of evidence for causation. Evaluating the impact of these changes will be difficult without a careful study of how well the current methods of causal inference work, their theoretical foundations, and the ethical implications of their applications. That research program will be most productive if it is jointly developed by public health professionals trained in the ethics and philosophy and by bioethicists and philosophers trained in the theories, methods, and practice of public health. (shrink)

This thesis is an examination of claims about the risk of global catastrophe. I present examples of models of global systems that predict catastrophe, if certain conditions prevail, and I explain their goals as well as give some of their history. I present arguments concerning the conditions of a good prediction, and arguments concerning the predictive weakness of ecological models, to conclude that models of global systems generating predictions of catastrophe leave us uncertain as to the likelihood of catastrophe. ;Next, (...) I examine the problem of action in the face of this uncertainty. There are those who argue that policy-makers should not react to scenarios of catastrophe until the evidence for them is strong. On the other hand, there are those who adopt the 'precautionary principle', which advises that lack of scientific evidence for a claim should not be taken as a reason for exercising a lack of caution when the risk is high. ;Some authors have argued that if normal canons of rationality cannot recommend maximum caution, then we should adopt a rival rationality that emphasizes democratic and ethical values. I will critique this view and reject it for its failure to distinguish properly between epistemic values and action-guiding values. ;Other authors argue for the precautionary principle on the grounds that we have an ethical obligation to avoid catastrophe, whatever the practical costs. There are, as well, purely prudential reasons in favour of the precautionary principle. Using arguments parallel to those of Blaise Pascal and William James, I will argue that the prudential reasons for precaution are overwhelming and should convince those not already persuaded by ethical arguments. While models of global systems can only reveal possible futures and not probable futures, the catastrophic threats posed by such things as global warming, ozone depletion, or population increase, though not firmly established, represent what James would call 'live options'; that is, they present us with a possibility that is at least plausible and that forces us to make momentous decisions. I conclude that we cannot afford to risk catastrophe despite the high costs this decision will involve. (shrink)