The Jacobsen Lecture 2017 with Prof Susanne Bobzien - Gestalt Shifts in the Liar

Prof Susanne Bobzien (Oxford University)

This lecture will be accessible to a general philosophical audience. A wine reception will follow.

Abstract

Something seems off with liar and truth-teller sentences. In this lecture, I will dig deeper into what this is and how it affects the liar paradox as well as our notion of truth and the logic that governs it. The main suggestion is that liar and truth-teller sentences are conceptually bi-stable. Different viewpoints make us take different and incompatible aspects as salient in those sentences. A change of viewpoint results in a Gestalt shift from one saliency to the other. For liar sentences this fact makes it impossible to determine their semantic status.

It turns out that without us shifting the Gestalt of a liar sentence, we cannot pinpoint a liar paradox. Thus the paradoxicality of the liar depends on an elusive pragmatic feature. This has consequences for the so-called liar property that are similar to those tackled by revision theories of truth. Rather than modifying the semantics of truth to accommodate the pragmatic feature, my approach is to let the nature of the pragmatic feature determine the semantics and logic of truth. This leads away from deflationist theories toward a notion of truth that has bivalence as its content, and toward a (classical) logic of truth in which bivalence and excluded middle come apart.

The Jacobsen Lecture

The Jacobsen Lecture was established in the 1980s following a donation to the University from Mr J. A. B. Jacobsen. Along with the Lecture, Mr Jacobsen also funded the creation of a research fellowship and an essay prize which are all on the subject of philosophy.

The Jacobsen trust funds are based at the Institute of Philosophy within the School of Advanced Study. The funds are overseen by the Jacobsen Committee which is comprised of academics from Philosophy Departments across the University of London Colleges.

Attendance is free of change but registration is required. Please register you attendance here - https://philosophy.sas.ac.uk/events/event/6758

For additional information please contact [email protected].