¹ See in particular Philosophy 53, No. 206 (October 1978).

² As a zoologist I have performed physiological and behavioural experiments on animals of all vertebrate classes within two medical schools, where such work is taken for granted as a basis for teaching and research, and, of more immediate relevance, in a school of agriculture, where it is seen as an integral part of the science of ‘animal husbandry and production’.

³ See Singer, Peter, Animal Liberation (London: Jonathan Cape, 1976)Google Scholar and ‘All Animals are Equal’ in Regan, T. and Singer, P. (eds), Animal Rights and Human Obligations (Englewood Cliffs, New Jersey; Prentice Hall, 1976)Google Scholar.

⁴ I am aware that on this definition it can plausibly be maintained that all living organisms have interests.

⁵ Albert Schweitzer. ‘The Ethics of Reverence for Life’; reprinted in Regan and Singer, op. cit., 134.

⁶ One who practises speciesism (see Ryder, Richard, ‘Life in the Laboratory’ in Godlovitch, S. and R. and Harris, J. (eds), Animals, Men and Morals (London: Gollancz, 1971), a form of prejudice with respect to other species which is essentially analogous to the prejudice people may have with respect to other races or the opposite sexGoogle Scholar.

⁷ From Modes of Thought, 1938; quoted by Thorpe, W. H., Animal Nature and Human Nature (London: Methuen, 1974), 211Google Scholar.

⁸ Thorpe, op. cit., 301.

⁹ Benson, John, ‘Duty and the Beast’, Philosophy 53, No. 206 (10 1978), 547CrossRefGoogle Scholar.

¹⁰ Francis, Leslie Pickering and Norman, Richard, ‘Some Animals are More Equal than Others’, Philosophy 53, No. 206 (10 1978), 507–527CrossRefGoogle Scholar.

¹¹ Diamond, Cora, ‘Eating Meat and Eating People’, Philosophy 53, No, 206 (10 1978), 470CrossRefGoogle Scholar.

¹² Charles Darwin, ‘Outline of the Evidence’ in The Descent of Man; reprinted in The Darwin Reader, M. Bates and P. S. Humphrey (eds) (London: Macmillan, 1957), 294.

¹³ Arthur Schopenhauer, ‘A Critique of Kant’; reprinted in Regan and Singer, op. cit., 125.

¹⁴ Biologists may, of course, soon be able to put together the vehicle that carries life.

¹⁵ Sherrington, Charles, Man on His Nature (London: Pelican reprint, 1955), 286Google Scholar.

¹⁶ Donald Vandeveer, ‘Defending Animals by Appeal to Rights’, in Regan and Singer, op. cit., 227.

¹⁷ Francis and Norman, op. cit., 527.

¹⁸ See in particular Regan, Tom, ‘The Moral Basis of Vegetarianism’, Canadian Journal of Philosophy 5, No. 2 (10 1975), 205–214CrossRefGoogle Scholar.

¹⁹ The neurophysiological evidence indicates that the sensation of pain is mediated by a distinct type of nerve fibre; i.e. pain does not seem to result from the over-stimulation of fibres that normally transmit other sorts of sensation, such as touch or temperature. This, however, in no way undermines the general validity and relevance of Aristotle's interpretation.

²⁰ Sherrington, op. cit., 286.

²¹ Sherrington, op. cit., 291.

²² Singer, Isaac Bashevis, Enemies, A Love Story (New York: Farrar, Strauss and Giroux, 1971), 256–257. (First quoted in this context by Tom Regan, op. cit., 181.)Google Scholar

²³ Orwell, George, Animal Farm (London: Penguin reprint, 1963), 114Google Scholar.

²⁴ Forster, E. M., Howards End (London: Edward Arnold, 1910), title pageGoogle Scholar.

²⁵ But whether society has the right to ask of an individual that he gain his livelihood working, for example, in a slaughterhouse, is another matter.

²⁶ Benson, op. cit., 545.

²⁷ I am grateful to Chris Cherry and Richard Norman for their generous advice and comments.