Naturalistic fallacy

In philosophical ethics, the naturalistic fallacy is the claim that it is possible to define good in terms of natural entities, or properties such as pleasant or desirable. The term was introduced by British philosopher G. E. Moore in his 1903 book Principia Ethica.^[1]

Moore's naturalistic fallacy is closely related to the is–ought problem, which comes from David Hume's A Treatise of Human Nature (1738–40); 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 naturalistic fallacy should not be confused with the appeal to nature, which is exemplified by forms of reasoning such as "Something is natural; therefore, it is morally acceptable" or "This property is unnatural; therefore, this property is undesirable." Such inferences are common in discussions of medicine, sexuality, environmentalism, gender roles, race, and carnism.