 Still, it may remain intuitively compelling that a Twin Earth thought experiment, if cogent, would show (1) apriori—even if E is just the condition where water  exists.[13]  For the experiments seem to show apriori that, to have the bona fide water concept, the concept must be non-empty, i.e., its referent must exist. However, a compatibilist can counter this by offering a semantics of empty concepts that is consonant with EXT (Stoneham 1999, Sawyer 2003, Goldberg 2006b, Haukioja 2006, Parent 2017, ch. 4; see also Pryor 2007, pp. 184–185). Even so, there are two arguments in the literature suggesting that any externalist view of empty concepts must fail (Boghossian 1997; 1998, Segal 2000, Besson 2012).