LIRa session: Jialiang Yan

Speaker: Jialiang Yan

Date and Time: Thursday, February 2nd 2023, 14:00-15:30
(NOTE the unusual time, earlier than usual)

Venue: fully online. (i.e. not hybrid) — A recording of this talk is available here.

Title: Knowing and believing an epistemic possibility

Abstract. What does it mean to know or believe that something might be the case? In this talk, we address the issue focusing on the epistemic possibility expressed by English might when embedded under the propositional attitude verbs know and believe. We present some puzzles to highlight the challenges arising from such know-might and believe-might sentences. We propose a framework to solve the puzzles, in which epistemic might is defined as quantifying over the epistemic possibilities in an information state, and belief is formalized in term of a plausibility ordering. In contrast to the classical epistemic logic, the factivity of knowledge is treated as a presupposition rather than being solely dependent on the reflexivity of the accessibility relation. All analyses are implemented in a team-based modal logic BSEL, an epistemic variant of Aloni’s (2022) BSML.