Experimental Ethics, with Shaun Nichols, in Hugh LaFollett, ed, International Encyclopedia of Ethics, Vol III: 1838-50.
Twin Earth, Moral, with Terry Horgan, in Hugh LaFollett, ed, International Encyclopedia of Ethics, Vol VIII: 5242-49.
A. C. Ewing, with Jonas Olson, in Hugh LaFollett, ed, International Encyclopedia of Ethics, Vol. III: 1817-23.
Objectivity in Moral Discourse, in Keith Brown, ed., Encyclopedia of Language and Linguistics, 2nd edition, vol. 9, Oxford: Elsevier (2006), pp. 5-10.
Singer, Marcus, Encyclopedia of Ethics, 2nd edition, vol. III, edited by Lawrence Becker and Charlotte Becker, New York and London: Routledge (2001), pp. 1584-86.
Nagel, Thomas, The Cambridge Dictionary of Philosophy, 2nd edition, edited by Robert Audi, Cambridge University Press, (1999), pp. 595-96.
Constitution, The Cambridge Dictionary of Philosophy, 2nd edition, edited by Robert Audi, Cambridge University Press (1999), pp.178-9.
Resultance,The Cambridge Dictionary of Philosophy, 2nd edition, edited by Robert Audi, Cambridge University Press, (1999), p. 794.
The Logic of Ethical Discourse, The Routledge Encyclopedia of Philosophy, edited by Edward Craig, London, Routledge (1998), pp. 759-64.
Constructivism, The Encyclopedia of Philosophy Supplement, New York: Macmillan (1996), pp.106-08.
Objective Rightness, The Cambridge Dictionary of Philosophy, edited by Robert Audi, Cambridge University Press, (1995), pp. 541-42.