The Jacobsen Lecture 2017 with Prof Susanne Bobzien

The Jacobsen Lecture 2017 with Prof Susanne Bobzien
15 May 2017, 17:30 to 15 May 2017, 19:30
The Chancellor's Hall, First Floor, Senate House, Malet Street, London WC1E 7HU

Gestalt Shifts in the Liar


Prof Susanne Bobzien (Oxford)


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.


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