Kohei Kishida — Quantified Logic for Modal Reasoning and Theorizing

Logic Supergroup — Online Colloquium, May 29, 2020 Kohei Kishida (Illinois) — Quantified Logic for Modal Reasoning and Theorizing Logicians and metaphysicians have developed various models and semantics of quantified modal logic. These semantics come with ontological and metaphysical implications regarding the references of singular terms --- such as the necessity of Hesperus being Phosphorus. My primary question in this talk is how these metaphysical facts can be a posteriori facts, as opposed to a matter of logic, of the sort that a cognizer can come to know. The goal of this talk is to give a semantics that sheds new light on this aposteriority. I will take an approach in terms of intensional logic that treats all singular terms, predicates, and quantifiers as uniformly intensional. Combined with epistemic logic, my approach will provide a semantics and logic in which metaphysical principles regarding cross-world reference are substantial facts that a cognizer can