The Logic and Metaphysics Workshop will meet on September 9th from 4:15-6:15 in-person at the Graduate Center (Room 4419) for a talk by Hartry Field (NYU).

Title: Well-behaved truth

Abstract: Common-sense reasoning with truth involves both the use of classical logic and the assumption of the transparency of truth (the equivalence between a sentence and the attribution of truth to it). The semantic paradoxes show that at least one of these must go, and different theorists make different choices. But whatever one’s choice, it’s valuable to carve out one or more domains where both classical logic and transparency can be assumed; domains where everything is *well-behaved*.  In this talk I’ll explore a method of adding a predicate of well-behavedness to various truth theories, which works for both classical and nonclassical theories (including non-classical theories with special conditionals). With such a predicate, one can reason more easily, and formulate and prove generalizations that are unavailable without such a predicate. Besides their intrinsic interest, these generalizations greatly increase the proof-theoretic strength of axiomatic theories.  (There are some previous proposals for adding a well-behavedness predicate to specific classical theories, and others for adding one to non-classical theories without special conditionals.  The current proposal, besides being general, is also more satisfactory in the individual cases, and is the only one I know of for non-classical theories with conditionals.)