quality:corruption, quality:correction
Principia Ethica

The first is G. E. Moore 's investigation into the nature of ethical terms (e.g., good) in his Principia Ethica (1903), which advances a kind of moral realism called ethical non-naturalism and is known for the open question argument and identifying the naturalistic fallacy, a major topic of investigation for analytical philosophers. According to Moore, " Goodness is a simple, undefinable, non-natural property."

Contemporary philosophers, such as Russ Shafer-Landau in Moral Realism: A Defence, defend ethical non-naturalism.