Naturalistic fallacy

In philosophical ethics, the term "naturalistic fallacy" was introduced by British philosopher G. E. Moore in his 1903 book Principia Ethica. Moore argues it would be fallacious to explain that which is good reductively in terms of natural properties such as "pleasant" or "desirable".

Moore's naturalistic fallacy is closely related to the is–ought problem, which comes from Hume's Treatise. 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.

The phrase "naturalistic fallacy" can also be used to refer to the fallacious appeal to nature, a mistaken claim that something is good or right because it is natural (or bad or wrong because it is unnatural). See below.

Different common uses

The is–ought problem

The term "naturalistic fallacy" is sometimes used to describe the deduction of an "ought" from an "is" (the is–ought problem).

In using his categorical imperative Kant deduced that experience was necessary for their application. But experience on its own or the imperative on its own could not possibly identify an act as being moral or immoral. We can have no certain knowledge of morality from them, being incapable of deducing how things ought to be from the fact that they happen to be arranged in a particular manner in experience.