Evolution has no moral direction. An evolutionary understanding of human nature can explain the differing intuitions we have when we are faced with an individual rather than with a mass of people, or with people close to us rather than with those far away, but it does not justify those feelings.
Peter SingerI don't think nationalism is alone holding the field; it's in contention with a lot of different things.
Peter SingerI'd much rather be part of a society which greatly honors and respects people who are altruists and who are effective in their altruism, than one that either admires people because they're, you know, celebrity movie stars or because they're super wealthy just no matter what they do with their wealth because I think we ought to try to encourage more people to act in that way.
Peter SingerSo far as this argument is concerned nonhuman animals and infants and retarded humans are in the same category; and if we use this argument to justify experiments on nonhuman animals we have to ask ourselves whether we are also prepared to allow experiments on human infants and retarded adults; and if we make a distinction between animals and these humans, on what basis can we do it, other than a bare-faced - and morally indefensible - preference for members of our own species?
Peter SingerAccording to classical utilitarianism, the only intrinsic good is happiness; the only intrinsic bad is pain. That implies no intrinsic value in preserving nature, that preserving an endangered plant is valuable only if it benefits humans or other animals. Intuitively, that seems wrong but perhaps I shouldn't trust my intuition here.
Peter SingerThe animal liberation movement is saying that where animals and humans have similar interests - we might take the interest in avoiding physical pain as an example, for it is an interest that humans clearly share with other animals - those interests are to be counted equally, with no automatic discount just because one of the beings is not human.
Peter Singer