John Finnis in the context of "Philosophy of law"

Moral realism (also ethical realism) is the position that ethical sentences express propositions that refer to objective features of the world (that is, features independent of subjective opinion), some of which may be true to the extent that they report those features accurately. This makes moral realism a non-nihilist form of ethical cognitivism (which accepts that ethical sentences express propositions and can therefore be true or false) with an ontological orientation, standing in opposition to all forms of moral anti-realism and moral skepticism, including ethical subjectivism (which denies that moral propositions refer to objective facts), error theory (which denies that any moral propositions are true), and non-cognitivism (which denies that moral sentences express propositions at all). Moral realism's two main subdivisions are ethical naturalism and ethical non-naturalism.

Most philosophers claim that moral realism dates at least to Plato as a philosophical doctrine and that it is a fully defensible form of moral doctrine. A 2009 survey involving 3,226 respondents from mostly English-speaking universities, including mostly faculty members, PhDs and graduate students, found that 56% accept or lean toward moral realism (28%: anti-realism; 16%: other). A 2020 study found that 62.1% accept or lean toward realism. Some notable examples of robust moral realists include David Brink, John McDowell, Peter Railton, Geoffrey Sayre-McCord, Michael Smith, Terence Cuneo, Russ Shafer-Landau, G. E. Moore, John Finnis, Richard Boyd, Nicholas Sturgeon, Thomas Nagel, Derek Parfit, and Peter Singer. Norman Geras has argued that Karl Marx was a moral realist. Moral realism's various philosophical and practical applications have been studied.