Is the precautionary principle reasonable?

The precautionary principle governs public policies to a large extent. Often considered poorly defined, it is however far from unanimous. D. Steel intends to defend a reasonable use of it, which in his eyes is essential.

A famous principle but attacked from all sides

Should we reduce cell phone emissions to prevent possible cancers, even if the cause and effect link is not established? Should a vaccine suspected of being dangerous be withdrawn from the market? Can a modest carbon tax be considered a good solution to the problem of global warming? Since the 1970s, a principle guiding the response to these questions has acquired increasingly broad legal recognition: the precautionary principle. Its general idea is that when an activity can lead to a disaster for human health or the environment, political measures should be taken to prevent it, even if the cause and effect relationship has not been fully established. established from a scientific point of view. We find, for example, a formulation in a document adopted in 1992 at the Earth Summit of theUN in Rio (principle 15), and the principle was enshrined in 2005 in the French Constitution within the Environmental Charter (article 5).

What is new about this precautionary principle is the idea that science does not need to provide certainty (or a high degree of confidence) in knowledge for it to be taken into account. . It is usually the opposite: a given product is only considered a vaccine, and will only be used as such, on the condition that studies have firmly established that it does indeed protect against a given disease. The precautionary principle reverses the burden of proof: faced with the possibility of a catastrophe, it requires that a product not be used or that an activity not be carried out.

However, the precautionary principle is not consensual neither in society nor among researchers, and it has been the target of numerous attacks. For example, it has been accused of being poorly defined, empty, incoherent, or of being an obstacle to scientific research. In his book Philosophy and the Precautionary PrincipleDaniel Steel sets himself an ambitious project: to re-examine the various controversies surrounding the precautionary principle, and to defend an interpretation that resists them. Steel’s approach is philosophical, focusing on fundamental problems of a conceptual nature. This does not mean that his work is too abstract or general: on the contrary, he discusses many concrete cases, such as the carbon tax, the use of growth hormones in cattle, or legislation on chemical substances.

What formulation and justification for the precautionary principle?

There are various formulations of the precautionary principle, and various ways of interpreting them. According to its critics, the precautionary principle faces a dilemma, depending on whether it is interpreted weakly or strongly. According to a weak interpretation, the principle states that “uncertainty does not justify inaction in the face of serious threats” (“uncertainty does not justify inaction in the face of serious threats”, p. 3), which seems quite empty or at least not very debatable. According to a strong interpretation of the principle, precautions should be taken “in the face of any scientifically plausible and serious environmental hazard”, p. 3, which seems inconsistent or irrational, “because environmental regulations themselves come with some risk of harmful effects and hence PP often precludes the very steps it recommends” (“because environmental regulations themselves contain risks of harmful effects and therefore the precautionary principle often prohibits precisely what it recommends”, p. 3); for example, banning a medication on the grounds that it could be dangerous may lead to having to use another, which could also be dangerous.

Steel seeks a path between these two pitfalls. A central element of his proposal is that there are different “versions” of the precautionary principle, which are obtained by varying three elements: the level of scientific knowledge (concerning the cause and effect relationship between the activity and the disaster) which is sufficient to trigger the application of the principle, the degree of danger (which counts as “catastrophe” in the statement) from which the principle applies, and finally the recommended precaution (which can vary from a complete ban on the activity to a slight reduction). By varying these three elements, we obtain different versions of the precautionary principle. Some fall into the failings described above, but others will escape them. To help identify them, Steel proposes to apply a requirement of proportionality between the degree of danger and the recommended precaution: for example, we will further restrict an activity that could lead to greater danger. A formulation which Steel particularly favors, even if he considers others, is the following: “If a scientifically plausible mechanism exists whereby an activity can lead to a catastrophe, then that activity should be phased out or significantly restricted (“If there is a scientifically plausible mechanism by which an activity can lead to disaster, then that activity should be phased out or significantly restricted,” p. 28). Steel presents proportionality as the key to a controlled application of the principle.

Another important and controversial question is what justifies using the precautionary principle. Some have sought to respond using ethical arguments, asserting that environmental and human health values ​​should take priority over economic values. But according to Steel, such an argumentative strategy suffers from flaws and is overall unconvincing. He prefers to develop a historical argument relating to environmental legislation: there exist “many cases of prolonged and ultimately costly delays in response to serious environmental problems, while rushes to unnecessary and seriously harmful environmental regulation are relatively rare” (“many cases of delays protracted and ultimately costly responses to serious environmental problems, and very few cases where superfluous and actually damaging legislation is taken too soon,” p. This observation calls for a corrective “to move policy making on environmental matters toward greater balance” (“to ensure that environmental legislation is taken with greater balance”, p. 70), and the precautionary principle is a perfect one. illustration. Steel defends this idea with new arguments, notably by showing that the historical induction on which it is based (since there have been many cases Cases of excessive precaution were rare or not very damaging.

Steel addresses other difficult questions, such as the definition of scientific uncertainty that the precautionary principle uses, or the place of social and political values ​​in science. Finally, it should be noted that the position defended by Steel remains quite general: he is not so much defending a precise formulation of the precautionary principle as a family of interpretations. Applying it in a real case will require the reader to make certain value judgments.

Towards a generalization of the precautionary principle?

Overall, Steel keeps his promise by defending a precautionary principle that avoids the pitfalls of weak and strong interpretations. The book discusses an impressive range of academic work on the precautionary principle and makes interesting connections to more general work in philosophy of science, ethics and epistemology. Steel’s argument is clear and easy to read (the formal technical developments are, for example, placed in the appendix).

Although the work resolutely confronts several classic problems posed by the precautionary principle, we close it with the feeling that certain “big questions” remained open. First of all, the work would have benefited from situating the precautionary principle more broadly in decision theory. For example, a classic concept in decision theory is risk aversion: having to choose between losing 1 euro for sure and having a one in two chance of losing 10,000 euros or winning 10,000 euros, someone preferring the first offer will be described as risk averse (her expectation of gain is lower, but she is sure not to lose big). Now if we interpret the loss of 10,000 euros as a catastrophe, and if the precautionary principle is interpreted as seeking to avoid catastrophe, it seems intuitively that it leads to choosing the first offer, i.e. risk aversion. It is regrettable that Steel does not discuss this kind of relationship with decision theory. More generally, can the precautionary principle be seen as a continuation of other decision-making rules? Is applying the precautionary principle compatible with a certain form of rationality?

Another limitation of the work concerns the area of ​​application of the precautionary principle. With an argument of historical induction that was indicated above, Steel justifies the precautionary principle for disasters in the field of health and the environment, at the level of legislation or regulation. However, on various occasions, he applies the precautionary principle to a much larger area (for example, I can apply the precautionary principle on my personal level and decide to wear a helmet when cycling because I know I overestimate my abilities to cycle safely). If the precautionary principle can (or must) apply more broadly than in laws aimed at avoiding health or environmental disasters, Steel does not provide a justification for it. However, this is a pressing question in today’s world: what is the maximum scope that such a principle can legitimately have? Can it be applied for example in the economic field to avoid financial crises, or in the field of diplomacy (through the use of preventive war)? There could be the risk that the precautionary requirements are too invasive, which again motivates the clarification of the place of this principle in the more general framework of decision theory.

Despite these criticisms, Daniel Steel offers a very interesting and convincing work, which philosophers of science, decision theories, lawyers and ecologists, interested in fundamental questions, will benefit from discussing.