Moore's argument for the indefinability of 'good' (and thus for the fallaciousness in the "naturalistic fallacy") is often called the open-question argument; it is presented in §13 of "Principia Ethica". The argument hinges on the nature of statements such as "Anything that is pleasant is also good" and the possibility of asking questions such as "Is it "good" that x is pleasant?". According to Moore, these questions are "open" and these statements are "significant"; and they will remain so no matter what is substituted for "pleasure". Moore concludes from this that any analysis of value is bound to fail. In other words, if value could be analysed, then such questions and statements would be trivial and obvious. Since they are anything but trivial and obvious, value must be indefinable.