The Irrelevance of the A Priori/Posteriori Distinction for the Epistemology of Logic

Abstract

When justifying knowledge of logic, philosophers tend to start with the claim that logic is a priori or a posteriori. With the help of an example involving the incompatibility between quantum mechanics and classical logic, I will examine the views on the epistemology of logic of Paul Boghossian – who claims logic is a priori – and of Ole Thomassen Hjortland – who claims logic is a posteriori. I will argue that, when faced with the crucial epistemological problem of having to decide between two competing logical theories, Boghossian and Hjortland turn out to have no use for their considerations on the apriority of logic.