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From Ideal Worlds to Ideality
Published online by Cambridge University Press: 21 November 2022
Abstract
In common treatments of deontic logic, the obligatory is what is true in all deontically ideal possible worlds. In this article, I offer a new semantics for Standard Deontic Logic with Leibnizian intensions rather than possible worlds. Even though the new semantics furnishes models that resemble Venn diagrams, the semantics captures the strong soundness and completeness of Standard Deontic Logic. Since, unlike possible worlds, many Leibnizian intensions are not maximally consistent entities, we can amend the semantics to invalidate the inference rule which ensures that all tautologies are obligatory. I sketch this amended semantics to show how it invalidates the rule in a new way.
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- Copyright © The Author(s), 2022. Published by Cambridge University Press on behalf of the American Philosophical Association
Footnotes
I shared parts of this material with students in my spring 2018 seminar on deontic logic, as well as audiences at Bowling Green State University and Northwestern University. Thanks to those in attendance, especially Fabrizio Cariani, Christian Coons, Molly Gardner, Michael Glanzberg, Joe Glover, John Hill, Ben Keoseyan, Brandon Warmke, Michael Weber, and others I've regrettably forgotten. Finally, I'm grateful for constructive feedback from the journal's referees.
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