Abstract

Applying two-dimensional modal semantics, some philosophers, most recently Frank Jackson and David Chalmers among others, have sought to provide analyses of Kripke’s examples of the necessary a posteriori. Despite the massive amount of attention that two-dimensionalism has received of late, Robert Nozick’s recent accounting of Kripke’s examples, which bears striking similarities to these two-dimensionalist analyses but reached a different conclusion, has gone unnoticed. This paper argues that (a) underlying such a difference is a serious problem with the two-dimensionalist approach to the necessary a posteriori and (b) thinking through this problem will go a long way towards a proper understanding, and thus assessment, of this approach.