MoL-2021-25: The Classicality of Epistemic Multilateral Logic

MoL-2021-25: Kortenbach, Bas (2021) The Classicality of Epistemic Multilateral Logic. [Report]

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Epistemic Multilateral Logic (EML) is a natural deduction system for multilateral modal logic. It has the notable feature that its valid inference patterns on the level of formulae seem to allign with those of classical logic, yet it intuitively invalidates certain classically valid metarules. This raises the issue of the extent to which EML can be thought of as classical. However, it is unclear precisely in which sense EML preserves classical logic on the inferential level and departs from it on the metalevel, as the idiosyncracies of the multilateral language prevent a straightforward comparison. We fix the situation by developing a systematic method for the comparison of multilateral to unilateral logics, and applying it to provide a detailed overview of the different ways in which EML conforms with, departs from and approaches classical logic. Along the way, we contribute to the general literature on higher level inferences by clarifying which notions of higher level validity are available, and how they relate to each other along various dimensions. The final results confirm that EML behaves classically only up to the basic inferential level, but also allow us to prove that this is as close to classicality as one can get within the multilateral framework.

Item Type: Report
Report Nr: MoL-2021-25
Series Name: Master of Logic Thesis (MoL) Series
Year: 2021
Subjects: Language
Depositing User: Dr Marco Vervoort
Date Deposited: 19 Dec 2021 14:03
Last Modified: 19 Dec 2021 14:03

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