Nuffield Council on Bioethics / Home

Ethics of Research involving animals

Can any use of animals by humans be justified? Which specific issues need to be considered in the case of research?

The moral status of different beings

3.20 It is common to begin reflection on the human use of animals by considering their relative moral status or moral importance (see Box 3.1). Within the current debate, we can identify three general positions, as follows.

• According to the first, there is a categorical moral dividing line between humans and animals. Human beings have a moral importance that animals lack. This we can call the clear-line view, and it is based on the assumption that there is something special about humans or that all humans possess some morally vital property that all animals lack.

• A second view is that there is not so much a clear dividing line as a continuum or moral sliding scale, correlated, perhaps, with a biological sliding scale of neurological complexity. Here, it is argued that there is a hierarchy in which humans are at the top end of moral importance, followed by primates and, for example, rodents such as mice and rats, with zebrafish, fruit flies and single-celled creatures arranged towards the bottom.

• A third view is to emphasise that biological classification is not by itself sufficient to support claims about a categorical moral distinction between human and non-human animals. It could hence be asserted that humans and either all, or at least some, animals, such as those that are sentient, are moral equals. Accordingly it could be argued that it is wrong to subject any animal (or any animal that is sentient) to treatment that would be unacceptable in the case of humans.

Box 3.1: Use of the terms ‘moral community’ ‘moral importance’ and ‘moral status’ The discussion of the three different moral views outlined in Box 3.2 introduces the idea that humans and animals could be described as having the same, or differing, moral status. This term, as well as other related important terms, requires some explanation. For the purpose of this discussion we use the term moral status or moral importance to refer to the circumstance that a being is a member of a moral community. Members of a moral community include moral agents and moral subjects. Moral agents are beings that are able to behave in a moral way and are liable to moral criticism for any failure to do so. Moral subjects are beings whose features should be taken into account in the behaviour of moral agents (see paragraphs 3.31–3.32). Beings differ in their moral status if differences in their entitlement to certain liberties or goods can be justified in a morally valid way. Moral agents are typically humans. There is some discussion as to whether animals are capable of behaving in moral ways. For example, there is evidence that some animals are capable of altruistic behaviour (see Box 3.2). However, the main discussion in this Report concerns the question of whether animals qualify as moral subjects. In this context it is useful to differentiate between direct and indirect reasons in support of such a view. One indirect argument was proposed by Immanuel Kant. Within his philosophical theory, animals deserve the status of a moral subject and should be treated humanely not because they have a right to flourish, or to be protected from harm, but because those people who are cruel to animals are more likely to be cruel to humans*. Others, however, put forward direct reasons in favour of viewing animals as moral subjects. They argue that the Kantian approach merely accords instrumental moral value to animals: animals are moral subjects because they can be used as an instrument for achieving the goal of making humans behave in a more moral way. Instead, critics argue that animals should be recognised as having inherent, or intrinsic, moral value. This view may be understood as saying that animals are valuable in themselves, that it matters to animals for their own sake how they are treated and that therefore their specific capacities need to be considered in interactions with them. The usual interpretation is that, as far as possible, animals should be free to live their lives without interference by humans. In general, all moral agents are also moral subjects, but not all moral subjects are moral agents. Differentiating between moral agents and moral subjects does not necessarily imply that one group is morally more important than another. For example, humans who are severely mentally disabled are usually not capable of being moral agents. But this does not mean, without further argument, that they are morally less (or more) important than those humans who are capable of being moral agents. Nonetheless, it is commonly assumed that animals, if they are seen to qualify as moral subjects, are less important than humans. We consider the reasons behind these perceptions, which are reflected in the practices of most Western societies, in paragraph 3.21 and throughout this chapter. * Heath P (Editor and translator) (2001) Immanuel Kant: Lectures on Ethics Schneewind JB (Editor) (Cambridge: Cambridge University Press).

3.21 It could easily be assumed that the justification for using animals for research (and other uses) depends entirely on the question of the relative moral status of humans and animals.
Then the defence of animal use would be the same task as showing that only humans have moral status, or that their status is in some way ‘higher’ than that of animals. But this assumption might be too simplistic. Suppose it was possible to establish that the clear-line view is true and that all humans are more important moral subjects than all animals. Yet, this is not enough to show that animals can properly be sacrificed for human purposes. For it may be that although humans are morally more important than animals, they have a moral duty of stewardship to ‘lesser’ beings, rather than a right to treat them as they please, as implied by one respondent to the Consultation:
‘The greater power of humans over other species brings with it a duty of care and compassion, not a licence to abuse.’ Alan St. John
Therefore, the permissibility of harmful animal research does not follow by necessity from the assumption that humans have a higher moral status than animals.

3.22 Similar arguments apply with respect to the sliding-scale view: although a hierarchy of importance of different animals seems intuitively plausible to many people, it faces the same challenge of the stewardship argument posed against the clear-line view. Despite its initial attractiveness the usefulness of the hierarchy is also called into question when one wishes to consider the acceptability of different types of research. For example, how should the following four types be ranked:

i) research involving mice with no, or very minor welfare implications;
ii) research involving primates with no, or minor, welfare implications;
iii) research involving mice with substantial welfare implications; and
iv) research involving primates with substantial welfare implications?

According to the sliding-scale view, the order of acceptability ought to be i, iii, ii, iv. However, for many people, the order i, ii, iii, iv, as presented above, would seem more plausible, suggesting that an unmodified version of this view is less attractive than initially assumed.

3.23 With regard to the moral-equality view, it needs to be remembered that even if humans and animals are considered to be moral equals, it does not necessarily follow that harming animals in research should not be carried out. Moral equality is simply the doctrine that humans and animals are moral equals. In principle, this view could allow for the conclusion that harmful experiments should be conducted both on animals and humans.8 Alternatively, the use of animals might be justified for practical reasons. For example, the reproduction rate of humans can be too slow for some experiments, or obtaining the quantity of a test chemical to dose humans could be impossible. Under these circumstances, it might be more appropriate to experiment on mice and rabbits, even if they are perceived as moral equals.
Finally, it could be argued that where research has a negative effect on welfare and animals are less affected than humans, it is preferable to use animals to minimise the overall harm.

3.24 In conclusion, consideration of the relative moral status does not settle the question of the permissibility of animal research, or of any other use of animals, in a helpful manner.
Although it is attractive to think that the question of justification is merely a matter of deciding whether the clear-line view, the sliding-scale view or the moral-equality view is the most adequate, this strategy may obscure more than it illuminates. Some people agree with this conclusion and refer instead to evolutionary theory as a justification of a relatively unrestricted right to use animals. Drawing on what can be termed the competitive argument, they may point out that different species must always compete for survival and that it is natural for any species to put itself first.

3.25 This argument is not compelling. The fact that humans have survived by dominating other species does not in itself show that we are morally justified in continuing to act in the same way. Humans have evolved a capacity to reflect upon their own behaviour. Much of this reflection has taken place by means of civilisation and especially education, which have channelled and changed ‘natural’ behaviour. Attitudes towards many forms of behaviour that were once justified as natural, as, for example, the dominance of men over women, or even the keeping of slaves, have changed substantially in a great number of societies (see also Box 3.4). Moreover, as we have said, if humans do indeed have a higher nature, this could entail duties of protection and stewardship for lesser beings, rather than the right of dominion (see paragraph 3.21).

3.26 Hence, it is clear that the competitive argument, which is based on the evolutionary order or the naturalness of certain behaviours, is unpersuasive in justifying ethically why it should be permissible for humans to use animals for research. It is crucial to distinguish between moral and scientific questions. Although, in particular cases, science may support particular moral conclusions, it can never be sufficient in itself to settle a moral question. Any argument for a moral conclusion needs to be based on moral premises or assumptions, although it may also draw on facts, including scientific ones. Understanding the relationship between the moral and the scientific questions is vital to achieving clarity in this discussion
(see paragraph 3.6).

Footnotes

8 Of course, humans do participate in medical research (see paragraphs 8.25–8.28 and box 11.1) but generally it is not harmful
and takes place with prior, voluntarily given consent.