WHY ‘ WATER ’ IS NOT AN INDEXICAL Christian Nimtz

Adherents of two-dimensionalist semantics have devised a powerful argument to show that the Kripke-Putnam semantics is in need of an overhaul. Kripke and Putnam take “Water is H2O” to be necessary as well a posteriori. But that cannot be true. For to claim that a proposition is necessary is to claim that it is true in all contexts, whilst to maintain that it is a posteriori or informative is to hold that there is at least one context in which it is false. In order to avoid the apparent contradiction, two-dimensionalists understand ‘water’ to be a context-dependent or indexical expression. We argue that even if one accepts the key ideas of a two-dimensionalist semantics, one need not and one should not maintain that ‘water’ is an indexical. On the one hand, we offer an analysis of the pragmatic role of indexicals that provides good reasons not to class ‘water’ with ‘I’ or ‘this monday’. From this we conclude that one should not maintain that ‘water’ is an indexical. On the other hand, we argue that the contradiction is only apparent since it stems from a flawed understanding of the a priori. We devise an adequate epistemic understanding of this notion and show that on this understanding the sketched contradiction does not arise. From this we conclude that one need not maintain that ‘water’ is an indexical.