Foundations of Ethics, Blackwell Publishing Ltd. Sinnott-Armstrong, Walter (2006a). "Moral Skepticism," The Stanford Encyclopedia of Philosophy, Edward N. Zalta (ed.). (link) Sinnott-Armstrong, Walter (2006b). Moral Skepticisms, Oxford University Press. van Roojen, Mark (2004). "Moral Cognitivism vs. Non-Cognitivism," The Stanford Encyclopedia of Philosophy, Edward N. Zalta (ed.). (link) About the queerness argument Brink, David O. (1984). "Moral Realism and the Sceptical Arguments from Disagreement and Queerness", Australasian Journal of Philosophy 62(2): 111–125. Garner, Richard T. (1990). "On the Genuine Queerness of Moral Properties and Facts", Australasian Journal of Philosophy 68(2): 137–46. Mackie, J. L. (1946). "A Refutation of Morals", Australasian Journal of Psychology and Philosophy 24: 77–90. Rosati, Connie S. (2006). "Moral Motivation", The Stanford Encyclopedia of Philosophy, Edward N. Zalta (ed.). Shepski, Lee (2008). "The Vanishing Argument from Queerness", Australasian Journal of Philosophy 86(3): 371–87. Amorality Meta-ethics Nihilism Nihilism