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Implications of moral uncertainty: implausible or just unpalatable?
  1. Mike King
  1. Correspondence to Dr Mike King, Bioethics Centre, University of Otago, Dunedin 9054, New Zealand; mike.king{at}

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Setting aside some complexities, Koplin and Wilkinson1 argue:

  1. Moral status is uncertain if there is a non-zero chance that an entity has, or would develop, full moral status.

  2. If its moral status is uncertain, then moral caution is warranted towards that entity.

  3. The moral status of both non-chimeric pigs and human-pig chimaeras is uncertain.

    (Conclusion 1) Therefore, consistency demands that moral caution is warranted towards both non-chimeric pigs and human-pig chimaeras.

  4. The commonly held view is that moral caution is warranted towards human-pig chimaeras, but not non-chimeric pigs.

    (Conclusion 2) Therefore, the commonly held view is inconsistent.

This is a valid argument. The authors claim that the inconsistency they expose in conclusion 2 could be resolved in favour of either commonly held view, or by revising both to equivalency. However, it is clear from conclusion 1, and the paper more generally, that the authors are arguing for moral caution to be applied to the treatment of pigs of both types.

I will focus on evaluating premises 1 and 2, and the generalisability of the argument in light of this. In doing so, I will attempt to show that the argument has implausible logical implications, and that the moral caution warranted towards human-pig chimaeras of uncertain moral status does not require confidence that they lack full moral status, as the authors claim.

According to premise 1, if an entity might currently have moral status, then its moral status is uncertain. That seems reasonable. However, the authors also argue that the moral status of human-pig chimaeras is uncertain if the animal ‘would have gone on to develop’ moral status-conferring cognitive capacities. This seems straightforwardly to be an endorsement of the argument from potential, well-rehearsed and responded to in the ethics of abortion. Objections to this argument notwithstanding,2 one of the implications of it is that moral caution ought to be applied to chimeric and non-chimeric pig embryos, pre-embryos or even mixtures of gametes. If pigs have full moral status, these could all go on to develop full moral status too.

These would have uncertain moral status and given both epistemic and philosophical uncertainty Koplin and Wilkinson cite, we should be uncertain about the moral status of other entities that could have full moral status: sentient and non-sentient animals, insects, plants, bacteria and artificially intelligent machines.3–8 Moreover, if we should be uncertain about these, we should be uncertain about whatever they develop from: fertilised eggs, seeds, the gametes of these and perhaps even the parts of machines, or machine learning algorithms.

Premise 2 claims that moral caution is warranted towards entities whose moral status is uncertain. The reason is that there is moral risk in our treatment of these entities. There is a range of degree, likelihood or both, of harm or wrong that our actions could cause to the entity. This seems like a plausible premise. I am less morally cautious opening a swinging door into a room in a children’s day care facility when I know it is empty than when I have reason to believe that there may be a child behind the door who could be hit by it. My uncertainty seems to justify moral caution; I open the door more carefully.

However, when this premise is combined with premise 1, it seems to have implausible implications. Given the extent of philosophical and epistemic uncertainty and the range of entities that are logically in scope, moral caution is quite a commitment. Even if moral caution is reasonably undemanding, it stretches plausibility that one ought to give any moral consideration to mixtures of plant pollen and ovules, let alone a lettuce, for example. Given the consistency between growing animals for organs and for food demanded by the argument, its logical scope makes veganism morally problematic too.

Nevertheless, let us assume that these are acceptable implications. Despite their reservations, the authors think the Moral Status No Alternative Principle (MSNAP) is a good approximation of the moral caution motivating the reluctance to harm human-pig chimaeras for which there is moral uncertainty. This principle permits any action that seriously harms beings with uncertain moral status in order to achieve a benefit only if there is no alternative action that would enable the benefit to be achieved without this harm. So in the absence of a viable completely synthetic diet, veganism is permissible despite the fact that we cannot be confident that plants lack moral status.

It is unclear why Koplin and Wilkinson believe this would only permit creation of human-pig chimaeras to produce transplantable organs if we can be confident that the animals would lack full moral status. Given the fact that many people die because of the organ shortage, it is clear that for some people they are lacking the beneficial option of a transplantable organ from non-chimeric sources. We are therefore justified by MSNAP in creating and seriously harming human-animal chimeric pigs in order to provide transplantable organs even if there is a reasonable fear that these animals would have full moral status. This justification holds as long as it benefits humans who would otherwise not receive that benefit.

Koplin and Wilkinson do not specify a level of benefit that must be achieved under MSNAP. This seems to be a mistake—they clearly believe that some benefits are more morally weighty than others, and that this is part of the assessment of moral risk and justification. If not, cosmetic benefits for humans that cannot be gained except through harmful use of human-animal chimeric pigs, or even aesthetic benefits from their use in BioArt would satisfy the principle. It would similarly justify farming and eating pigs in those cases where an adequate diet for reasonable health could not be provided otherwise, and the benefit of satisfying a preference for eating meat.

To address this, MSNAP should contain the further requirement that the benefits of the course of action being sought are sufficient to justify serious harm to the entity of uncertain moral status. Now we are faced with the familiar debate of the relative moral status of humans, animals, plants and so on. This would restrict the scope of justified uses referred to above. However, it is still not clear that it would rule out harvesting transplantable organs from human-pig chimaeras of uncertain moral status; the uncertainty would seem to give the pig a weaker claim to moral protection than the human whose life could be prolonged only by this transplant. However, the argument would still make most farming and eating animals morally unjustifiable, but would permit a vegan diet, at least until the alternative of completely synthetic diets is available. This may be an implausible ethical view, or perhaps merely unpalatable, but if its implausible premises are true, it is logical.



  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; internally peer reviewed.

  • Patient consent for publication Not required.

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