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Single Idea 10559

[filed under theme 4. Formal Logic / D. Modal Logic ML / 1. Modal Logic ]

Full Idea

Kripke's modal semantics presupposes that worlds are maximal and consistent, that there is a unique actual world, and that worlds are coherent (e.g. lack contradiction, obey conjunction).

Gist of Idea

Kripke's modal semantics presupposes certain facts about possible worlds

Source

report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Edward N. Zalta - Deriving Kripkean Claims with Abstract Objects

Book Ref

-: 'Nous' [-], p.4


The 18 ideas with the same theme [general ideas about the nature of modal logic]:

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Quantified modal logic collapses if essence is withdrawn [Quine]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