ExpressivismIn meta-ethics, expressivism is a theory about the meaning of moral language. According to expressivism, sentences that employ moral terms – for example, "It is wrong to torture an innocent human being" – are not descriptive or fact-stating; moral terms such as "wrong", "good", or "just" do not refer to real, in-the-world properties. The primary function of moral sentences, according to expressivism, is not to assert any matter of fact but rather to express an evaluative attitude toward an object of evaluation.
EmotivismEmotivism is a meta-ethical view that claims that ethical sentences do not express propositions but emotional attitudes. Hence, it is colloquially known as the hurrah/boo theory. Influenced by the growth of analytic philosophy and logical positivism in the 20th century, the theory was stated vividly by A. J. Ayer in his 1936 book Language, Truth and Logic, but its development owes more to C. L. Stevenson. Emotivism can be considered a form of non-cognitivism or expressivism.
Universal prescriptivismUniversal prescriptivism (often simply called prescriptivism) is the meta-ethical view that claims that, rather than expressing propositions, ethical sentences function similarly to imperatives which are universalizable—whoever makes a moral judgment is committed to the same judgment in any situation where the same relevant facts pertain. This makes prescriptivism a universalist form of non-cognitivism. Prescriptivism stands in opposition to other forms of non-cognitivism (such as emotivism and quasi-realism), as well as to all forms of cognitivism (including both moral realism and ethical subjectivism).
Moral nihilismMoral nihilism (also known as ethical nihilism) is the meta-ethical view that nothing is objectively morally right or objectively morally wrong. Moral nihilism is distinct from moral relativism, which allows for actions to be wrong relative to a particular culture or individual. It is also distinct from expressivism, according to which when we make moral claims, "We are not making an effort to describe the way the world is ... we are venting our emotions, commanding others to act in certain ways, or revealing a plan of action".
Cognitivism (ethics)Cognitivism is the meta-ethical view that ethical sentences express propositions and can therefore be true or false (they are truth-apt), which noncognitivists deny. Cognitivism is so broad a thesis that it encompasses (among other views) moral realism (which claims that ethical sentences express propositions about mind-independent facts of the world), ethical subjectivism (which claims that ethical sentences express propositions about peoples' attitudes or opinions), and error theory (which claims that ethical sentences express propositions, but that they are all false, whatever their nature).
Non-cognitivismNon-cognitivism is the meta-ethical view that ethical sentences do not express propositions (i.e., statements) and thus cannot be true or false (they are not truth-apt). A noncognitivist denies the cognitivist claim that "moral judgments are capable of being objectively true, because they describe some feature of the world". If moral statements cannot be true, and if one cannot know something that is not true, noncognitivism implies that moral knowledge is impossible.
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.
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).
Anti-realismIn analytic philosophy, anti-realism is a position which encompasses many varieties such as metaphysical, mathematical, semantic, scientific, moral and epistemic. The term was first articulated by British philosopher Michael Dummett in an argument against a form of realism Dummett saw as 'colorless reductionism'. In anti-realism, the truth of a statement rests on its demonstrability through internal logic mechanisms, such as the context principle or intuitionistic logic, in direct opposition to the realist notion that the truth of a statement rests on its correspondence to an external, independent reality.
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.
