What is a Natural Property?

Abstract

In Principia Ethica Moore held that the meaning of the word ‘good’ is a simple, unanalysable, non-natural property. Several features of this claim might be questioned. It might be questioned whether there are properties at all, and whether, even if there are, they are ever the meanings of words. Again, it might be questioned whether the word ‘good’ expresses a property, even assuming that some other words do. Moore considers this latter question, but not the former (in Principia Ethica). The two questions may seem connected by the fact that a negative answer to the first trivially leads to a negative answer for the second. But this triviality should be a caution to us. Otherwise we may confuse nominalism with ethical non-cognitivism or ‘anti-realism’.