The Argument from Superior Aliens’ InvasionJohn Harris advances the following consideration to show the immorality of eating meat.
Suppose that tomorrow a group of beings from another planet were to land on Earth, beings who considered themselves as superior to you as you feel yourself to be to other animals. Would they have the right to treat you as you treat animals you breed, keep, and kill for food?
The implication is certainly that it would be inconsistent for us to think that it is morally permissible for us to eat nonhuman animals but wrong for superior aliens to eat us.
But it is not clear that it is inconsistent if there is a relevant moral difference between animals and humans not found between humans and superior aliens. Our discussion above of the concept of person suggests a difference. Most human beings and presumably all of Harris’s aliens are persons. Most animals are probably not persons. Consequently, if personhood is the ground for the right to life, there need be no inconsistency in maintaining that it is morally permissible for us to kill and eat most animals, given that we cause them no pain, preserve the ecological balance, and so on, and that it is wrong for the aliens to kill and eat us, even though they kill us painlessly and so on.
KBJ: The following three propositions are inconsistent:
The truth of any two of these propositions entails the falsity of the third. Since the propositions are inconsistent, every rational person must reject at least one of them. Harris rejects 3. Martin rejects 1. Do you know of anyone who rejects 2? Please don’t say that there aren’t any superior aliens. We don’t know that; and even if there aren’t, there could be, and it therefore makes sense to ask what one would say about them if they came here and wanted to eat us.1. There is no morally relevant difference between humans and animals that would (a) justify the eating of animals by humans without (b) justifying the eating of humans by superior aliens.
2. It is wrong for superior aliens to eat humans.
3. It is not wrong for humans to eat animals.