LIRa Session: Matías Osta Vélez

Speaker: Matías Osta Vélez (Ruhr-University Bochum)

Date and Time: Thursday, October 28th 2021, 16:30-18:00, Amsterdam time.

Venue: online.

Title: Nonmonotonic reasoning, expectation orderings, and conceptual spaces


Gärdenfors and Makinson (1994) showed that it is possible to model non-monotonic inference by means of a classical consequence relation together with an ordering of formulas representing our expectations about the world. However, an important limitation of their approach is that it does not explain the cognitive origins and structure of these expectations. This talk aims to offer a solution to this problem using the theory of conceptual spaces. The central claim is that our expectations about the world depend, to a significant extent, on the prototypical structure of our categories. Building on this idea and focusing on how we reason about properties and objects, we advance a typicality measure based on the metric structure of conceptual spaces. We then show how this measure generates an ordered set of expectations that can be used as default rules with variable strength in non-monotonic inference. Finally, we discuss various ways in which these sets are updated in the light of new information and we present an application of this model to the conjunction fallacy.