(For other posts in this series, see here.)

Our current attitudes towards nonhuman animals seem to be based on two assumptions. The first is that all humans are believed to be equal in some sense and one person has no right to exploit another. The second is that nonhuman animals are somehow inferior to humans and thus have lesser rights and can be used for our benefit. But how do we justify this distinction?

Philosopher Peter Singer points out that people are manifestly not equal in all kinds of ways, some important and some trivial, and this realization has important consequences.

Equality is a moral idea, not an assertion of fact. There is no logically compelling reason for assuming that a factual difference in ability between two people justifies any difference in the amount of consideration we give to their needs and interests. The principle of equality of human beings is not a description of an alleged actual equality among humans; it is a prescription of how we should treat human beings. (Italics in original. From his book Animal Liberation, excerpted in Writings on an Ethical Life by Peter Singer (2000), p. 31)

Of course, meat eaters can always take ultimate refuge by invoking speciesism, by just arbitrarily deciding that other members of our own species deserve more consideration from us than other species.

But this is not a moral argument. It is just as arbitrary as earlier rules that we now despise as racist or sexist, that argued that other races or women were intrinsically inferior and thus did not deserve the same rights. As Singer argues, “To exclude the chimp from moral consideration simply because he’s not human is no different than excluding the slave simply because he’s not white.” (Michael Pollan, The Omnivore’s Dilemma, 2006, p. 308)

To avoid pleading guilty to the charge of naked speciesism, those who feel that humans have some property that entitles them to be privileged over nonhuman animals have looked for at least one quality that humans possess that animals don’t (or at least possess to a significantly lesser degree) that would justify such differential treatment.

But finding such a marker proves to be remarkably elusive. Although human beings do possess certain features that are unique it is hard to argue that those features give us the right to kill those animals that do not possess that feature, any more than the fact that the elephant has a unique trunk gives it the right to kill and eat other animals. One has to make the case why that quality matters in a morally significant way.

Animal rights philosophers like Peter Singer have squarely targeted the various candidates proposed for this privileging property and come to the conclusion that no such marker exists.

What about intelligence or language, something that humans undoubtedly possess? The problem is that it is not the case that all humans possess more intelligence or language than all nonhumans. For example, an adult chimp or dog or horse could well have more intelligence, or communicate better, than a newborn infant, and yet we accord the infant full rights while denying them to the animals.

A chimpanzee, dog, or pig, for instance, will have a higher degree of self-awareness and a greater capacity for meaningful relations with others than a severely retarded infant or someone in a state of advanced senility. So if we base the right to life on these characteristics, we must grant these animals a right to life as good as, or better than, such retarded or senile humans. . . . What we must do is bring nonhuman animals within our sphere of moral concern and cease to treat their lives as expendable for whatever trivial purposes we may have. (From his book Animal Liberation (1975), excerpted in Writings on an Ethical Life by Peter Singer (2000), p. 45)

So “If possessing a higher degree of intelligence does not entitle one human to use another for his or her own ends, how can it entitle humans to exploit non-humans for the same purpose?” (Michael Pollan, The Omnivore’s Dilemma, 2006, p. 307)

The argument that the infant has the potential to develop into a fully intelligent human being does not work either because there are a few sad cases where an individual, due to birth defects or injury, is severely retarded and will never develop much. In fact, any quality that we can name that has the possibility of being used to give preferential treatment to humans runs into the problem that we can always find a few humans who, due to a host of reasons, have less of that quality than some nonhuman animals. And yet we always give preference to the ‘inferior’ humans over the ‘superior’ animal.

This kind of argument against giving privileged status to the right of humans is called the ‘argument from marginal cases’ and is a powerful one.

Next: The role of pain and suffering

POST SCRIPT: Pointless

Since I am known as someone who follows politics, I am sometimes asked to comment on who I think will be the likely vice-presidential picks of Obama and McCain. This is a topic about which I feel it is useless to speculate. What’s the point? When the candidates are good and ready, they will pick someone on the basis of criteria that they deem important. Since those criteria are kept secret from us, any name is as likely as any other.

Of course, there are people that I would prefer and whom I think would help the candidate. But those are based on my criteria and there is no reason to think that the candidates are using the same criteria.

So why don’t we just forget about this topic until the candidates are ready to tell us?