Leśniewski’s strategy and modal logic

Abstract

Leśniewski used formal systems and artificial languages to capture and explore concepts expressed in ordinary language. This strategy, which is the appropriate strategy for the philosophical logician, is illustrated by developing a system of modal logic to investigate the concept of analyticity. The ordinary concept of analyticity applies only to sentences; it is de dicto. This is a shortcoming of the ordinary concept, which is overcome by extending the concept to constitute the corresponding de re concept. A semantic account and a deductive system are developed for a first-order language with identity to capture this concept. The system is shown to be sound and complete with respect to the semantic account. © 1989 by the University of Notre Dame. All rights reserved.