LIRa session: Aybüke Ozgun

Speaker: Aybüke Ozgun (LORIA, Nancy and ILLC, Amsterdam)

Date and Time: Friday, October 28th 2016, 15:00-16:10

Venue: KdVI Seminar Room F3.20, Science Park 107.

Title: Justified Belief, Knowledge and the Topology of Evidence

Abstract: In this talk, I will present a topological semantics for evidence-based belief, as well as for a notion of (“soft”, defeasible) knowledge, and explore their connections with various notions of evidence possession. We will not only focus on truthful evidence but also formalize conceptions of possibly false and misleading evidence. The basic pieces of evidence possessed by an agent are modelled as non-empty sets of possible worlds and form a primitive component of our models. I will argue that our setting generalizes the evidence models for belief due to van Benthem and Pacuit (van Benthem et al., 2011), as well as our own previous work (Baltag et al., 2013) on topological semantics for Stalnaker’s doxastic-epistemic axioms (Stalnaker, 2006). We prove completeness, decidability and finite model property for the associated logics. If time permits, we will also talk about the link between our setting and some of the important discussions in Epistemology such as Stability and Defeasibilty Theory of Knowledge.
This is a joint work with Alexandru Baltag, Nick Bezhanishvili and Sonja Smets.