The philosophical term coined by G.E. Moore early in the twentieth century to devalue drawing ethical conclusions from empirical observation -- i.e. by moving from what is (facts that are observed) to what ought (morality). Moore felt that ethics should be intuitive, not inferred -- therefore he presumably favored deontological ethics over teleological ethics. Practical ethicists find this constraint unnaturally crippling as it prevents them making a value judgement.
English philosopher G. E. Moore's term for any efforts attempting to get an “ought” from an “is.” Considered to be an specious concept by science of ethics.
G. E. Moore's claim that good cannot be defined as it is simple and indefinable. Moore famously compared it to yellow, which, if defined was no longer yellow.