23/05/2017 — Guilherme Araújo Cardoso

Situation Theory and the Liar Paradoxes
Guilherme Araújo Cardoso*
State University of Campinas

The Liar Paradoxes are usually taken to show that some very basic assumptions about the natural concept of truth are not jointly consistent. First assumption is that Classical Logic is the background logic for this concept. Second assumption is that natural language has its very own truth predicate. Last, we assume T-Schema (or T-Rules): p iff T r(p), where T r(x) is a truth predicate. Considering the expressive power of natural language, some try to block paradoxes by changing the background logic. Two important families that take this road are the Gap Views and the Glut Views. Roughly speaking, Gap Views (like [4] and [2]) accept that some propositions are neither true nor false and Glut Views accept that some propositions are both true and false (like, [3]). Those are very good ideas concerning paradoxes and the concept of truth.
However, there are bad consequences for these two views. There is a different idea provided by Situation Theory (presented by Barwise and Etchemendy in [1]) that intends to deal with the liar paradoxes in a classical background, also considering the expressive power of natural languages.
The purpose of this communication is to present Situation Theory as an alternative to Gap and Glut Views.

Keywords: Liar Paradoxes, Gaps, Gluts, Situation Theory and Revenge Problem.

[1] Barwise, J. and Etchemendy, J. The Liar: an essay on truth and circularity. OUP. New York. 1987.
[2] Kripke, S. Outline of a Theory of Truth. In Journal of Philosophy, volume 72, pp. 690-716. 1975.
[3] Priest, G. In Contradiction. OUP. Oxford. 2006.
[4] Van Fraassen. Pressuposition, Implication and Self-Reference. In Journal of Philosophy, volume 65(5), pp. 136-152. 1968.

*Posdoctoral student at Centro de Lógica, Epistemologia e História da Ciência da Universidade Estadual de Campinas (CLE-Unicamp), sponsored by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Contact: guilhermeprimeiro@gmail.com