Logicality, invariance and semantic constraints

Mathematics and Philosophy Seminar

• Speaker: Dr Gil Sagi (University of Haifa)
• Title: Logicality, invariance and semantic constraints

The talk (including discussion) will last approximately one hour and will be followed by refreshments. All welcome!

For more information please contact the convenors, Dr Salvatore Florio and Dr Laura Crosilla.

Abstract

In this lecture we look into the model-theoretic definition of logical consequence. This definition leans on a division of the vocabulary into logical and nonlogical terms: the logical terms are completely fixed by models, whereas the nonlogical terms remain variable. While Tarski left the characterization of the logical vocabulary open, philosophers in recent years have proposed various criteria for logical terms. We shall focus on invariance criteria as those proposed by McGee, Sher and Feferman and assess their merits. We shall then consider an alternative model-theoretic framework where there is no strict division of the vocabulary into logical and nonlogical. The models in this framework are determined by sets of semantic constraints which fix the meaning of terms in different manners and to various degrees. We shall then also see how invariance criteria can be implemented in this framework.