LIRa Session: Peter Hawke

Speaker: Peter Hawke (ILLC)

Date and Time: Thursday, March 28th 2019, 16:30-18:00

Venue: ILLC Seminar Room F1.15, Science Park 107.

Title: Logical Omniscience and Knowledge Per se.

Abstract. I’ll report on the latest developments in an ongoing project on the problem of logical omniscience, emphasizing recent technical developments (joint work with Aybuke Ozgun and Franz Berto). A problem of logical omniscience arises, roughly, when, relative to a class of agents, (i) one’s theory of an epistemic attitude is committed to it being closed under logical implication, and (ii) this is, prima facie, a misrepresentation of that attitude. We concentrate on a fundamental version of the problem, concerning ordinary knowledge ascription (‘knowledge per se’) and arbitrary agents. Though logical omniscience is obviously problematic for a theory of knowledge per se, it is plausible that knowledge per se obeys some (static and dynamic) logical principles. We try to capture this with three complementary tools: (i) taking content as composed of truth conditions and topic; (ii) taking minds as fragmented; (iii) taking knowledge as defeasible. We compare our logical system to related ones and exhibit soundness and completeness results.