 But to the contrary, it is possible to imagine “weird worlds” where (II) ends up false (Ebbs 2001). Consider a world much like this one, where H2O fills the lakes and rivers, etc., and where ‘water’ refers to H2O. The difference is that ‘Earth’ in this weird world does not denote the planet that the skeptic currently occupies. Rather, it denotes Twin Earth. In that case, when the skeptic states (II), the proposition expressed is that if he is on Twin Earth, then asserting ‘water is scrumptious’ expresses the thought that water (i.e. H2O) is scrumptious. (Remember that ‘water’ in this scenario still denotes H2O.) Yet if that is what (II) expresses, then the skeptic says something false. And so, since the skeptic apparently cannot exclude a weird world from the armchair, he cannot prove to himself that (II) is true. So once more, the skeptic cannot justifiably adopt (II) while assuming (III).