[45] See J. L. Mackie, Ethics: Inventing Right and Wrong (London: Penguin Books, 1977), and his articles, "The Law of the Jungle: Moral Alternatives and Principles of Evolution," Philosophy 53, no. 206 (1978): 455-464, "Genes and Egoism," Philosophy 56, no. 218 (1981): 553-555, and "Co-operation, Competition, and Moral Philosophy," in J. L. Mackie, Persons and Values: Selected Papers. Vol. 11, ed. John Mackie and Penelope Mackie (Oxford: Oxford University Press, 1985): 152-169.