 This interplay of criticism and defence characterizes the Orthodox interpretation of the argument. (See Fogelin [1976], pp. 162–4, for a good example.) There seem to be at least two reasons why this interpretation should have become established. First, philosophers committed to the idea of a private language are often looking for an arrangement in which mistakes of fact are impossible; that is, they are trying to overcome scepticism by finding absolute certainty. (Descartes is the example usually cited.) And this would make sceptical arguments appear to be natural weapons to use in reply to them. (See, e.g., Fogelin [1976] p. 153.) Secondly, it is plausible—which is not the same as correct—to suppose that one cannot be mistaken concerning the natures of one’s present sensations, and a supposed proof that the idea of a private language entails that one is just as fallible on this subject as on any other could thus seem crippling to that idea.