The ontological status accorded to non-human animals has obvious consequences for the morality of our willingness to use them for our own purposes. Kant argued that animals do not qualify as members of the kingdom of ends among whom morality properly holds, while Bentham supposed that the evident pleasure and pain experienced by animals deserve to be included in any utilitarian calculation. More recently, Mary Midgley makes concern for animals central to moral philosophy, Peter Singer shows that mistreatment of animals is the result of a morally indefensible 'speciesism,' and Tom Regan argues that animals are entitled to basic rights.

Recommended Reading: Mary Midgley, Animals and Why They Matter (Georgia, 1998); Tom Regan, The Case for Animal Rights (California, 1985); Peter Singer, Animal Liberation (Avon, 1991); RJane Bennett, The Enchantment of Modern Life: Attachments, Crossings, and Ethics (Princeton, 2001); Paola Cavalieri, The Animal Question: Why Non-Human Animals Deserve Human Rights, tr. by Catherine Woolard (Oxford, 2001); Dale Jamieson, Morality's Progress (Oxford, 2002); Richard Alan Young and Carol J. Adams, Is God a Vegetarian? Christianity, Vegetarianism, and Animal Rights (Open Court, 1998); and Michael P. T. Leahy, Against Liberation: Putting Animals in Perspective (Routledge, 1994).

Also see the Animal Rights Resource Site, IEP, Ethics Updates, SEP, and EB.