GROLOG/LIRa Logic Afternoon

Date and Time: Monday, July 1st 2019, 14:00-17:00

Venue: Room Beta, Faculty of Philosophy, Oude Boteringestraat 52, Groningen.

Speaker #1: Roberto Ciuni (University of Padova)

Title: Information-based oughts and their interaction with knowledge and belief.

Abstract. In this talk, I present a conditional logic that enables us to reason about information-based oughts and the role they play in decision-theoretical scenarios that crucially involve knowledge and beliefs. Unconditional oughts and beliefs turn to be special cases of their conditional counterparts. The paper proceeds as follows. After providing a bit of background and setup, I introduce the notions of an objective ought and an information-based ought, and we present a maximality-based semantics for them and the doxastic notions we deal with, in the style of Hansson, Board, van Benthem, Baltag and Smets. Finally, I present a complete axiom system for the resulting logic.

Speaker #2: Louwe Kuijer (University of Liverpool)

Title: Minimal rationality constraints for conditional obligation.

Abstract. A conditional obligation is of the form O(p|q), with the meaning that p is obligatory under the condition that q is true. We can give semantics to this O operator using a preference relation on states, by saying that O(p|q) holds if p is true on all the “best” q states.

But of course that does not fully determine the semantics unless we specify what we mean by a state being one of the “best”. There are several options: we could say that a states is “best” if it is maximal (i.e., there is no other state that is strictly preferred) or if it is optimal (i.e., weakly preferred over all other states). Here, we take a different option and say that a state is among the “best” states if it is part of at least one so-called minimal retentive set. Defining “best” in this way leads to a weak logic for O, but we can find contexts where this weak logic is the appropriate choice.

In this talk I will (i) introduce the semantics for O based on minimal retentive sets and give an example, (ii) introduce a sound an complete axiomatization, and discuss how it differs from other axiomatizations of conditional obligations and (iii) briefly discuss the challenges encountered while defining a canonical model for this logic.

Speaker #3: Karolina Krzyzanowska (ILLC, University of Amsterdam)

Title: True clauses, false connections, and the limits of pragmatic explanations.

Abstract. It is a common intuition that the antecedent of an indicative conditional should have something to do with its consequent, that they should be somehow connected. However, only very few theories of conditionals do justice to this intuition. In fact, many prominent accounts of indicative conditionals validate the Principle of Conjunctive Sufficiency that allows to infer a conditional from the truth of its antecedent and the consequent. Consequently, many odd conditionals whose antecedents and consequents are not connected at all are rendered true, or highly acceptable, on these accounts. Their proponents tend to dismiss the oddness of such conditionals as a pragmatic phenomenon, outside the scope of interest of a semanticist or a logician. This is not to say that no pragmatic explanations of the oddity of missing-link conditionals have been proposed. In my talk, I will discuss the most salient of these proposals and I will present empirical data that show how they all fail.

The talks will be followed by drinks and dinner with the speakers.

For more information about the GROLOG seminar and scheduled events, please check the GROLOG seminar webpage.