A defence of the Kaplanian theory of sentence truth

Abstract

When David Kaplan put forward his theory of sentence truth incorporating demonstratives, initially proposed in ‘Dthat’ (1978) and later developed in ‘Demonstratives’ (1989a) and ‘Afterthoughts’ (1989b), it was, to his mind, simply a matter of book-keeping, a job that had been pushed aside as a complication when a truth conditional semantics had been proposed. The challenges considered in this thesis are challenges to the effect that Kaplan’s theory of sentence truth is, for one reason or another, inadequate. My overarching aim is to defend Kaplan’s theory of sentence truth against these challenges. In chapter one I am concerned only with setting out some preliminary considerations. In chapter two I defend Kaplan’s theory of sentence truth against a general challenge, motivated by linguistic data from ‘contextualists’ and ‘relativists’. I argue that the methods and data employed by proponents of contextualism and relativism are lacking and as such should not be taken to have seriously challenged Kaplan’s theory of sentence truth. In chapter three I defend Kaplan’s theory of sentence truth against challenges to the effect that his theory is not suited to delivering on its initial purpose—to provide a semantics for indexical and demonstrative terms. I then develop a form of semantic pluralism that I take to be entirely compatible with the Kaplanian model. In chapters four I demonstrate the efficiency of this Kaplanian model when it comes to defending Kaplan’s theory against the challenge of providing suitable semantics to accommodate discourse involving future contingents. And finally, in chapter five I consider contextualist accounts of discourse concerning vague predicates.