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.
Moral sense theoryMoral sense theory (also known as moral sentimentalism) is a theory in moral epistemology and meta-ethics concerning the discovery of moral truths. Moral sense theory typically holds that distinctions between morality and immorality are discovered by emotional responses to experience. Some take it to be primarily a view about the nature of moral facts or moral beliefs (a primarily metaphysical view)—this form of the view more often goes by the name "sentimentalism".
Moral skepticismMoral skepticism (or moral scepticism in British English) is a class of meta-ethical theories all members of which entail that no one has any moral knowledge. Many moral skeptics also make the stronger, modal claim that moral knowledge is impossible. Moral skepticism is particularly opposed to moral realism: the view that there are knowable and objective moral truths. Some defenders of moral skepticism include Pyrrho, Aenesidemus, Sextus Empiricus, David Hume, J. L.
Moral universalismMoral universalism (also called moral objectivism) is the meta-ethical position that some system of ethics, or a universal ethic, applies universally, that is, for "all similarly situated individuals", regardless of culture, race, sex, religion, nationality, sexual orientation, gender identity, or any other distinguishing feature. Moral universalism is opposed to moral nihilism and moral relativism.
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.
MoralityMorality () is the differentiation of intentions, decisions and actions between those that are distinguished as proper (right) and those that are improper (wrong). Morality can be a body of standards or principles derived from a code of conduct from a particular philosophy, religion or culture, or it can derive from a standard that a person believes should be universal. Morality may also be specifically synonymous with "goodness" or "rightness".