  There may be as much philosophical controversy about how to distinguish naturalism from non-naturalism as there is about which view is correct. In spite of this widespread disagreement about the content of naturalism and non-naturalism there is considerable agreement about the status of certain historically influential philosophical accounts as non-naturalist. In particular, there is widespread agreement that G.E. Moore’s account of goodness in Principia Ethica is a paradigmatically non-naturalist account. Indeed, if a representative sample of contemporary philosophers were asked to name a non-naturalist in meta-ethics then Moore’s name almost certainly would predominate.  For better or worse, Moore’s discussion of non-naturalism profoundly shaped 20th century meta-ethics. Thomas Baldwin was not exaggerating much when he claimed that, “twentieth century British ethical theory is unintelligible without reference to Principia Ethica; its history until 1960 or so being, in brief, that although Moore was taken to have refuted ‘ethical naturalism’, Moore’s own brand of ‘ethical non-naturalism’ was thought to make unacceptable metaphysical and epistemological demands; so the only recourse was to abandon belief in an objective moral reality and accept an emotivist, prescriptivist or otherwise anti-realist, account of ethical values.” (Baldwin 1990: 66) More recent defenders of non-naturalist theories (e.g. Shafer-Landau 2003, Enoch 2011, and Parfit 2011) often distinguish their accounts from Moore’s in a number of ways, but few if any would dispute that Moore’s account is a paradigmatically non-naturalist one.