Combining Texts

All the ideas for '67: Platonic Questions', 'A Completeness Theorem in Modal Logic' and 'The Logical Syntax of Language'

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7 ideas

4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
10163 Propositional modal logic has been proved to be complete [Kripke, by Feferman/Feferman]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / a. Systems of modal logic
10760 With possible worlds, S4 and S5 are sound and complete, but S1-S3 are not even sound [Kripke, by Rossberg]
4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
16189 The variable domain approach to quantified modal logic invalidates the Barcan Formula [Kripke, by Simchen]
15132 The Barcan formulas fail in models with varying domains [Kripke, by Williamson]
5. Theory of Logic / B. Logical Consequence / 1. Logical Consequence
13342 Carnap defined consequence by contradiction, but this is unintuitive and changes with substitution [Tarski on Carnap]
5. Theory of Logic / C. Ontology of Logic / 4. Logic by Convention
13251 Each person is free to build their own logic, just by specifying a syntax [Carnap]
15. Nature of Minds / A. Nature of Mind / 2. Psuche
5960 When the soul is intelligent and harmonious, it is part of god and derives from god [Plutarch]