The idea of the precautionary principle when discussing animal sentience is that, when the present evidence of sentience is inconclusive, we should “give the animal the benefit of the doubt” in formulating animal protection legislation. In this paper, the author highlights that there is confusion on whether the precautionary principle is appropriate for animal sentience considerations, and if so, what its application means in practice.

The paper includes a proposed version of the precautionary principle tailored to the question of animal sentience together with a practical framework for implementing it. The author explains and defends its key features and offers opinions on a number of popular counterarguments.

The Precautionary Principle

How much evidence should it take to convince us that an animal is sentient? It’s a question many cultures and lawmakers are struggling with right now. Indeed, in some countries, some version of the precautionary principle has led to extending the scope of animal protection legislation to encompass fish and some invertebrates. Unfortunately, when the principle is presented to avoid mistreating sentient beings as non-sentient, it is often deemed unscientific and vague by critics.

For some context, when the term ‘sentience’ is used in animal welfare science and ethics, it usually refers to subjective experiences such as pain, suffering, pleasure, frustration, anxiety, fear and happiness. Below are the proposed definitions for an implementable precautionary principle, with a scientific threshold that has to be met to invoke protective status, and what action should then be taken.

The Principle: Given threats of serious and negative animal welfare outcomes, lack of full scientific certainty as to the sentience of the animals in question shall not be used as a reason for postponing cost-effective measures to prevent those outcomes.

The Threshold: In formulation of animal protection legislation, there is sufficient evidence that animals of a particular order (or other orders relevant via phylogenetic inference) are sentient if there is statistically significant evidence, obtained by experiments that meet high scientific standards, of the presence of at least one credible indicator of sentience in at least one species of that order.

The Action Plan: The scope of animal protection legislation should include all orders of animals for which the evidence of sentience is sufficient, according to the standard of sufficiency outlined in the threshold. Then cost-effective measures to safeguard the welfare of these animals should be included in any legislation relevant to their treatment in any domain of human activity, including food production, scientific research, conservation work and recreational pursuits. In cases when it is disputed whether an order meets the threshold, it may be appropriate to commission prioritized research into determining the animals’ sentience.

The above outline hinges on two key points: firstly, when a scientific hypothesis that posits a causal relationship between human action and a seriously bad outcome is proposed, we should set an intentionally low evidential bar for the acceptance of that hypothesis due to the high potential risk. And secondly, once we have sufficient evidence of such a threat, we should act in a timely and cost-effective manner to prevent that outcome.

In other words, the precautionary reasoning aims to create a pathway from evidence to action that circumvents the often slow turning wheels of science and policy, and allows for timely responses to serious threats.

Countering The Counterarguments

With the above in place, the author addresses three categories of common counterarguments: bureaucracy vs. welfare, international competition, and the issue of replacements. Examples are given below:

• Claims have been made that extending the scope of EU animal protection law “…would bring large areas of research that were previously not regulated under bureaucratic control without any tangible animal welfare benefits.” However, the author claims that the alternative lack of any proper regulatory oversight creates a risk of serious welfare consequences. If an animal is not regarded as sentient, for example, practices that would be considered inhumane if performed on a protected species, such as the removal of limbs without anaesthetic or analgesic, may be allowed to persist.
• The second concern is that extending the scope of animal protection legislation could undermine the international scientific competitiveness of the nation implementing the regulations, and create an incentive for scientists to conduct some of their experimental work elsewhere. The author tackles this by providing an analogy – climate change. Substantial measures to reduce carbon emissions could potentially undermine the international economic competitiveness of the countries that implement them, however such effects are to be minimized as far as possible, and should not serve as a reason to reject the need for such measures. The imperative to prevent serious harm should, arguably, override economic or even scientific interests of a particular nation.
• In some cases, animal replacement takes the form of replacing vertebrates with invertebrates, on the grounds that vertebrates may have a richer, more complex form of sentience. The author notes, however, that it seems reasonable that a greater degree of sentience should imply a greater degree of regulatory oversight, although this raises the question of how degrees of sentience are to be quantitatively compared. The author argues that a more sophisticated incentive structure is needed where there would not be any space for intentionally leaving potentially sentient “lower” animals outside of the scope of animal protection to continue work.

The proposed overarching principle and its practical implementations provide a framework for applying it to the question of animal sentience. When implemented, such a principle could offer a kind of a shortcut decision procedure that would be applied in cases when action must be taken quickly to mitigate a serious risk, but a quantitative analysis of expected consequences is hard to come by, or simply hasn’t been done yet.

Animal advocates will find these suggestions interesting as a successful implementation of the precautionary principle is vital to significant progress in sentient animal protection. However, it is also important to realize that high quality scientific evidence is imperative as it could be the only way to ensure that the protection of more animals is not successfully obstructed by the powerful forces that resist it.