9728 | Modal Square 1: □P and ¬◊¬P are 'contraries' of □¬P and ¬◊P [Aristotle, by Fitting/Mendelsohn] |
9729 | Modal Square 2: ¬□¬P and ◊P are 'subcontraries' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn] |
9730 | Modal Square 3: □P and ¬◊¬P are 'contradictories' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn] |
9731 | Modal Square 4: □¬P and ¬◊P are 'contradictories' of ¬□¬P and ◊P [Aristotle, by Fitting/Mendelsohn] |
9732 | Modal Square 5: □P and ¬◊¬P are 'subalternatives' of ¬□¬P and ◊P [Aristotle, by Fitting/Mendelsohn] |
9733 | Modal Square 6: □¬P and ¬◊P are 'subalternatives' of ¬□P and ◊¬P [Aristotle, by Fitting/Mendelsohn] |
13591 | Quantified modal logic collapses if essence is withdrawn [Quine] |
10928 | Maybe we can quantify modally if the objects are intensional, but it seems unlikely [Quine] |
16951 | It was realised that possible worlds covered all modal logics, if they had a structure [Dummett] |
10163 | Propositional modal logic has been proved to be complete [Kripke, by Feferman/Feferman] |
16985 | Possible worlds allowed the application of set-theoretic models to modal logic [Kripke] |
10559 | Kripke's modal semantics presupposes certain facts about possible worlds [Zalta] |
15163 | The interest of quantified modal logic is its metaphysical necessity and essentialism [Soames] |
10206 | Modal operators are usually treated as quantifiers [Shapiro] |
9924 | Modal logic gives an account of metalogical possibility, not metaphysical possibility [Burgess/Rosen] |
5744 | First-order predicate calculus is extensional logic, but quantified modal logic is intensional (hence dubious) [Melia] |
5745 | Quine says quantified modal logic creates nonsense, bad ontology, and false essentialism [Melia] |
19209 | Simple Quantified Modal Logc doesn't work, because the Converse Barcan is a theorem [Merricks] |