Possible worlds semantics and the liar

Sten Lindström

pp. 297-314

in: Artur Rojszczak, Jacek Cachro, Gabriel Kurczewski (eds), Philosophical dimensions of logic and science, Berlin, Springer, 2003

Abstract

In this paper I discuss a paradox, due to David Kaplan, that in his view threatens the use of possible worlds semantics as a model-theoretic framework for intensional logic.¹ Kaplan's paradox starts out from an intuitively reasonable principle that I refer to as the Principle of Plenitude. From this principle he derives a contradiction in what he calls Naive Possible World Theory. Kaplan's metatheoretic argument can be restated in the modal object language as an intensional version of the Liar paradox.

Cited authors

Kaplan David