Moral realism is the philosophical doctrine that moral claims are cognitive claims that are at least sometimes true. Moral realism, therefore, contrasts with non-cognitivism (which variously holds that moral claims are prescriptions, commands, or expressions of one's emotions, affective disposition, or acceptance of norms) and "error-theories" of morality (which hold that moral claims are indeed cognitive, but are all completely mistaken). Some moral realists include David Brink, John McDowell, Peter Railton, Geoffrey Sayre-McCord, Michael Smith, and Thomas Nagel.
