Is–ought problemThe is–ought problem, as articulated by the Scottish philosopher and historian David Hume, arises when one makes claims about what ought to be that are based solely on statements about what is. Hume found that there seems to be a significant difference between descriptive or positive statements (about what is) and prescriptive or normative statements (about what ought to be), and that it is not obvious how one can coherently transition from descriptive statements to prescriptive ones.
Naturalistic fallacyIn philosophical ethics, the naturalistic fallacy is the claim that it is possible to give a reductive explanation of good, in terms of natural properties such as pleasant or desirable. The term was introduced by British philosopher G. E. Moore in his 1903 book Principia Ethica. Moore's naturalistic fallacy is closely related to the is–ought problem, which comes from David Hume's A Treatise of Human Nature (1738–40). However, unlike Hume's view of the is–ought problem, Moore (and other proponents of ethical non-naturalism) did not consider the naturalistic fallacy to be at odds with moral realism.
Moral realismMoral 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.
Ethical naturalismEthical naturalism (also called moral naturalism or naturalistic cognitivistic definism) is the meta-ethical view which claims that: Ethical sentences express propositions. Some such propositions are true. Those propositions are made true by objective features of the world. These moral features of the world are reducible to some set of non-moral features. The versions of ethical naturalism which have received the most sustained philosophical interest, for example, Cornell realism, differ from the position that "the way things are is always the way they ought to be", which few ethical naturalists hold.
MetaethicsIn metaphilosophy and ethics, metaethics is the study of the nature, scope, and meaning of moral judgment. It is one of the three branches of ethics generally studied by philosophers, the others being normative ethics (questions of how one ought to be and act) and applied ethics (practical questions of right behavior in given, usually contentious, situations).
EthicsEthics or moral philosophy is a branch of philosophy that "involves systematizing, defending, and recommending concepts of right and wrong behavior". The field of ethics, along with aesthetics, concerns matters of value; these fields comprise the branch of philosophy called axiology. Ethics seeks to resolve questions of human morality by defining concepts such as good and evil, right and wrong, virtue and vice, justice and crime. As a field of intellectual inquiry, moral philosophy is related to the fields of moral psychology, descriptive ethics, and value theory.
