Moral realism is the view in philosophy that there are objective moral values. Moral realists argue that moral jugments describe moral facts. This combines a cognitivist view about moral judgments (they are truth-evaluable mental states that describe the state of the world), a view about the existence of moral facts (they do in fact exist), and a view about the nature of moral facts (they are objective; that is, independent of any cognizing of them, or any stance towards them, etc.). It contrasts with expressivist or non-cognitivist theories of moral judgment (e.g., Stevenson, Hare, Blackburn, Gibbard, Ayer), error theories of moral judgments (e.g., Mackie), fictionalist theories of moral judgment (e.g., R. Joyce, M. Kalderon) and constructivist or relativist theories of the nature of moral facts (e.g., R. Firth, Rawls, Korsgaard, Harman).