The Semantics and Psychology of Negation: The Australian Plan, Negation as Failure, and Card Selection Tasks

September 20, 2023

Abstract: In this talk, I will explain how two different kinds of semantics for negation can be used to help us understand some puzzles in the psychology of reasoning. I introduce the “Australian Plan” semantics for negation, which generalises the semantics of negation as found in “worlds” semantics for intuitionistic logic, relevant logics and other substructural logics; and semantics from logic programming and default logic which treat negation as failure. I provide a framework in which two kinds of semantic clauses for negation coexist, and use this to model to give a possible account of why reasoners fare differently in card selection tasks depending on whether the target property is phrased positively or negatively.

This talk reports joint work with Francesco Berto.


I’m Greg Restall, and this is my personal website. I am the Shelby Cullom Davis Professor of Philosophy at the University of St Andrews, and the Director of the Arché Philosophical Research Centre for Logic, Language, Metaphysics and Epistemology I like thinking about – and helping other people think about – logic and philosophy and the many different ways they can inform each other.


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