• precautionary principle
• anthropocentrism
• principlism

Anthropocentrism—the idea that humans are the most important beings there are—comes in many guises. One version of anthropocentrism states that only humans have full moral status. Those who argue for such a position (beyond merely assuming it) usually refer to some trait that confers moral status and that only humans have. Suggestions include linguistic ability, self-awareness or rationality. However, regardless of what trait one picks it will not track the line between Homo sapiens and other species. You will always be able to find some non-human animal that possesses the trait to a greater degree than some human does— even potentially. Koplin and Wilkinson1 adopt a broadly sentientist position: moral status is conferred by some mental or cognitive function. They discuss two sources of moral uncertainty related to this. In cases of moral uncertainty of the first type, it is uncertain whether Property X confers (full) moral status. In cases of uncertainty of the second type, we assume it to be true that moral status is conferred by X, but it is uncertain whether a particular entity (such as a pig) possesses the property. There are reasons to believe that moral uncertainty is the rule rather than the exception.

Even though Koplin and Wilkinson1 frame their discussion of using human-pig chimaeras as being about moral status, their arguments are in fact more generally applicable: it does not make a difference what type of moral uncertainty is present and they could as well simply be about likelihood of harm. In either case, the problem of whether or not to use human-pig chimaeras for organ generation and similar purposes is very much a practical problem. To what extent do Koplin and Wilkinson’s1 proposals help us in addressing the problem? Unfortunately, not enough.

Koplin and Wilkinson’s1 two principles (the ‘Moral Status Precautionary Principle’, MSPP, and the ‘Moral Status No Alternative Principle’, MSNAP) are presented as versions of the precautionary principle (PP). It is certainly not the first time that versions of PP have been applied to problems in biomedical ethics.2 As the authors are well aware, the PP has been subject to a number of critiques. One of these critiques states that PP leads to decisional paralysis, since it will in effect ban every action: If we take the PP as banning each action that might lead to some specific morally unacceptable outcome, and since this arguably holds for every action, PP will be self-defeating. A related critique states that is that even if not incoherent, PP might be counterproductive, leading to worse risks than it was designed to avoid.3 4 Now this need not be an unsurmountable problem for PP in practical applications. As Koplin and Wilkinson1 write, they might be addressed by restricting the scope of PP or adding a requirement of proportionality and a ‘similar response might be open to proponents of the MSPP’. The latter is in effect what is achieved by introducing a restricted version of PP (ie, MSNAP), in which the risk of harm is allowable only as a last resort,

According to Koplin and Wilkinson,1 MSPP and MSNAP are ‘a good approximation of the kinds of intuitions that underlie many people’s reluctance to inflict serious harm on human-pig chimaeras with humanised brains’. This is not dissimilar to the two precautionary intuitions cited by Sandin and Peterson:5 first, the uncontroversial intuition that taking precaution is sometimes warranted. Second, that there are cases in which precaution is obviously right (‘core cases’). However, to transfer such intuitions into principles for decision-making is no easy feat. First, the intuitions can be endorsed event though one subscribes to no particular principle whatsoever (as particularists might argue). Second, there might be other intuitions that speak equally strongly in favour of some other principle than PP. We might have one intuition that could be spelled out as ‘better safe than sorry’—incidentally, this proverb is often mentioned as an interpretation of PP—, while at the same time holding a strong and plausible intuition of ‘nothing ventured, nothing gained’.

One way of approaching the problem that will be familiar to anyone versed in medical ethics would be to interpret PP as a moral mid-level principle, in the vein of Beuchamp and Childress.5 6 Mid-level principles do not offer ultimate moral justification. Neither do they (usually) offer direct action-guidance, but they are general principles from which more concrete action-guiding principles might in some cases be derived. On this view, PP is non-rigid, meaning that it can, and should, be balanced against other non-rigid principles, for instance, a version of the cost-benefit principle.

Koplin and Wilkinson1 do not actually get around to doing this kind of work. As described now their principles will be consistent with the intuitions they refer to, but too sweeping, and possibly in conflict with other intuitions. MSPP, it seems, will for instance rule out any form of animal experimentation. As indicated by the authors’ own discussion of how humans’ view animals, there should be a reasonable fear that we are mistaken about the moral status of the animals we use in research (mice, rats and so on). MSNAP will perhaps fare a little bit better in his respect, assuming that we do not at present have alternatives to animal experimentation in some cases.

It is possible that Koplin and Wilkinson1 would endorse such a conclusion, but more elaboration is certainly needed. As it is now, their principles will lend themselves to ban almost anything they wish to ban.