This paper is the result of feeling that Singer’s argument for animal equality in his paper ‘All Animals are Equal’ deserves to be taken more seriously than it often is. What I try to do is identify Singer’s essential argument and then defend it against some objections I have come across.
The ‘irrelevance argument’
Singer begins by assuming that the ‘principle of equality’ or ‘principle of equal consideration of interests’ is a basic moral principle. The principle says ‘treat all people as equals’, meaning ‘give equal consideration to the interests of all people’, or ‘treat the interests of all people as equally important’, regardless, for example, of their skin colour, or gender, or sexual orientation. So racism, sexism and homophobia are violations of the principle of equality; they are practices that ‘discriminate’ so as to favour the interests of one group of people over those f others. In fact another title for the principle might be the ‘principle of non-discrimination’.
Singer then proposes that we should ‘extend’ or ‘reinterpret’ the principle of equality so that it applies not just to all humans but to all sentient beings, by which he means all beings that are capable of suffering or happiness or enjoyment (from here on I shall just say ‘suffering or happiness’ for short). So the principle becomes ‘treat all sentient beings as equal’ or ‘give equal consideration to the interests of all sentient beings’, regardless of which species, or which group within a species, they belong to.
Singer gives three kinds of advocacy to support this extension of the principle of equality, of which only the third is a real argument.
First, he says that extending the principle to include non-humans is an ‘expansion of our moral horizons’. The implication is that our present moral outlook is somehow narrowly self-centred because it focuses (almost) exclusively on the human race, and we should adopt a more universal standpoint. But this assumes that a more universal standpoint is better than a more particularistic one, that a ‘wider horizon’ is better than a ‘narrower one’, and Singer does not say why we should think this. So this is not yet an argument.
Second, he points to the succession of modern liberation movements that have demanded that the principle of equality be extended to black people, gays and women, and been largely successful in those demands (in that almost everyone today agrees that the principle of equality should apply across all those different groups, even if actual practice often does not match up to that). This is not an argument as such either, but it suggests that this historical extension is not just a matter of chance or just the result of socio-economic changes (such as the development of the division of labour), but rather that it is the result of the human race following out a certain ‘logic of universality’. The further extension of the principle of equality to all sentient beings would simply be taking this logic to its final conclusion.
You might think that Singer is relying on a very small slice of history here, namely the last two or three hundred years in the West, but one can argue that this process of universalisation has occurred over a longer time-span in the West, for example in the successive interpretations of the idea that you should ‘love your neighbour as yourself’ in the Bible. This command first appears in Leviticus, where God gives it to Moses. From the context it is clear that ‘neighbour’ means either ‘someone who lives near you’ or ‘a member of your own people’. The full verse is:
You shall not take vengeance or bear a grudge against the sons of your own people, but you shall love your neighbour as yourself: I am the Lord. (Leviticus 19:18)
In fact a little later in the same series of commands God explicitly prohibits the Israelites from enslaving each other, while advising them to enslave members of other peoples...