Guest essay John Ridgway

The precautionary principle has so often been the subject of articles on this website that one is slightly embarrassed to be adding to the pile. Nevertheless, I couldn’t resist the temptation to add my own two pennyworth, particularly after reading the article posted by Neil Lock on the same subject earlier this month.

Whilst I appreciate that Mr Lock’s essay made a number of important points, it still remains, for me, a deeply problematic article that overlooks the most important aspects of the precautionary principle and post-normal science. So I hope Mr Lock will forgive me if my contribution is framed as a critique of his offering.

The Precautionary Principle and Tyranny

Firstly, I think I need to clarify an important point regarding the development of the precautionary principle. Mr Lock alludes to pre 1980s forms of the principle but declines to identify them. Instead, various aphorisms, such as ‘look before you leap’, are provided, each of which captures an aspect of precaution but none of which had ever been referred to as an enunciation of ‘the precautionary principle’. In fact, the first documented use of the term was a translation of the German expression ‘Vorsorgeprinzip’, as used in the German Clear Act of 1974.

Far from being a nitpicker, I feel I am making an important point here by stressing that, in its original guise of Vorsorgeprinzip, the precautionary principle already embraced the concepts that Mr Lock attributes to the principle’s strong versions, i.e. from the outset the principle emphasized that scientific certainty is not required in order to justify precaution, nor was there ever any suggestion that the burden of proof initially rested with the regulator. There never was a development from a weaker version of the principle that simply called for care and attention prior to proceeding with a venture. Admittedly, since then, several reformulations of the principle have been declared, all of which have simply added to the confusion.¹ But to characterize the history of the precautionary principle’s development as one of ever-increasing ‘tyranny’ I feel misses the mark.

Risk Aversion Versus Uncertainty Aversion

Secondly, it seems to me (particularly after reading what Mr Lock had to say regarding risk management) that there is a misconception that the precautionary principle is about aversion to risk. This is not the case; it is instead a principle that promotes uncertainty aversion.² Rather than encouraging the avoidance of risk, the principle seeks to advise on how to proceed when we have reason to suspect that a risk exists but we do not have enough information to quantify it (or, indeed, even to confirm its existence). For many policy makers, not being in a position to know the scale of a risk is sufficient reason to presume that it is unacceptable, particularly when the stakes are high and the impacts are potentially irreversible. Whereas risk aversion is akin to fear of snakes, uncertainty aversion is akin to fear of the dark, within which one cannot rule out the possible presence of snakes. Once again, this distinction has always been at the core of the precautionary principle.

Rather than taking a more risk averse position, the strong versions of the principle differ from the weak versions with respect to the extent to which sanctions and proscription should be enforced in order to achieve what are considered to be appropriate levels of uncertainty aversion in the face of potentially irreversible outcomes. All versions, both weak and strong, are equally clear in their advocacy of uncertainty aversion over risk aversion and none of them have anything particular to say about how risk averse one should be in any given circumstance. That said, the strongest versions do not even allow for the calculation of risk (or costs and benefits, for that matter) presumably since this is seen as futile in the face of the uncertainties. This is not so much a draconian attitude as a defeatist retreat from rationality.

To further emphasize this point, I would refer the reader to the UNESCO COMEST (2005) review of the principle, in which it is stated that deep uncertainty can preclude the calculation of probability and hence the ability to evaluate risk levels. In such circumstances, it is maintained, one cannot then base decisions upon calculated risk. Instead, one has to base the decisions upon an aversion to the uncertainty upon which the posited risk is predicated, combined with a consideration of the impact defined for the risk.

In such circumstances, plausibility takes on a new importance³ and imagination can run riot. If unchecked, this can result in credence being placed in fanciful concerns. The obvious solution is to reduce uncertainty by undertaking further research. However, if the posited risk is formulated in such a way as to suggest that resulting delays are likely to heighten the risk level, then uncertainty aversion, i.e. the precautionary principle, will win the day.

I think I should stress at this point that I seek to clarify the logic behind the precautionary principle but not to defend it. There are many good reasons for distrusting the principle. For example, as well as the cognitive bias of uncertainty aversion one can add omission bias, the focusing effect and neglect of probability as biases that both underpin and undermine the principle. You can also add to this the fact that the logic of the principle is profoundly self-defeating, since the deep uncertainty that precludes reliable risk calculations can apply whether taking action or not. Thereby, the principle can be used to simultaneously justify proscription of both action and inaction.

In summary, whilst I share Mr Lock’s disquiet with regard to the precautionary principle, I suspect I do so for different reasons. I do not see any evidence of ‘perversion’ of a basic concept, and I think that the distinction between weak and strong versions is misrepresented by his article. However, I do accept that there is plenty of scope, for those who are politically motivated, to take advantage of the perverting influence of uncertainty aversion and its distortion of the perception of risk.

Quality and Evidence

Turning to post-normal science, I find myself more closely aligned with Mr Lock but, even here, I feel that his article misrepresents.

The kinship between post-normal science and the precautionary principle lies in the fact that they are both attempts to address the same problem – how to proceed when uncertainty and expedience conspire to undermine confidence. However, whereas fear and various conceptions of political pragmatism may lie behind both, post-normal science differs in claiming epistemological roots. It is the non-absolutist nature of the Popperian philosophy that is taken by some as a free reign to take a postmodern stance towards scientific knowledge, in which all subjective opinion is valid as long as it is to some extent evidence based. Deciding between competing hypotheses then becomes a democratic process moderated by quality control. The danger with this view is that rhetoric gains undue significance, and consensus itself is taken as evidence. This is precisely the error made by the IPCC when they suggest that high levels of confidence are justified even when consensus exists in the face of low quality evidence.⁴

It isn’t the problem-solving nature of post-normal science that troubles me, since, after all, this is a feature shared with the standard Popperian approach. What I object to is the suggestion that science is a democracy in which authority, credentials and orthodoxy carry weight over evidence. This is not an inherent feature of post-normal science, but it is definitely a potential result of its misapplication. In particular, as the quality of evidence falls (or, more cynically, as appetite for evidence weakens) one will eventually arrive at a position where falsifiability and reproducibility of results become irrelevant. It is only at this point that post-normal science can be fairly dismissed as ‘nonsience’.

A Call for Restraint

I hope this article does not come across as being too disobliging or harsh in its criticism of Mr Lock’s viewpoint. I do not dispute that both the precautionary principle and post-normal science are problematic. However, I feel that criticisms of them should be qualified by a full appreciation of their provenance and purpose. By talking about ‘tyranny’ and ‘nonscience’ we run the risk of hyperbole that does not stand up to close examination. Concerns regarding the precautionary principle and post-normal science are valid enough without overstating the case.

Notes

¹ Part of the confusion regarding the precautionary principle lies in the fact that it isn’t actually a principle, it isn’t just about precaution and there are now several declarations of it, all different but all claiming to represent the principle.

² All risk is predicated upon uncertainty but it is not a function of uncertainty. Instead, uncertainty impacts upon the perception of risk, often, though not always, resulting in an increased interest in the potential for risk. Risk aversion and uncertainty aversion (or ‘ambiguity aversion’, as it is sometimes known) are, therefore, very different. For example, Daniel Ellsberg, in 1961, demonstrated how logically equivalent gambles may be treated unequally, simply because individuals consider subjective probabilities to be less reliable than objectively determined probabilities. Consequently, individuals can be fooled into accepting gambles with a lesser payoff, in violation of expected utility theory. These individuals are not more risk averse, they have simply misperceive the risk because they are concerned by the uncertainty or ambiguity inherent in subjective probabilities.

³ As explained in the COMEST review, “the unquantified possibility is sufficient to trigger the consideration of the Precautionary Principle”.

⁴ See, Mastrandrea M. D., et al (2011). The IPCC AR5 guidance note on consistent treatment of uncertainties: a common approach across the working groups. Climatic Change 108, 675 – 691. doi: 10.1007 / 10584 – 011 – 0178 – 6, ISSN: 0165-0009, 1573 – 1480.