Combining Texts

All the ideas for 'Conditionals', 'A Completeness Theorem in Modal Logic' and 'Life of Pythagoras'

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9 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]

10. Modality / B. Possibility / 8. Conditionals / a. Conditionals

13768

Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington]

10. Modality / B. Possibility / 8. Conditionals / b. Types of conditional

13770

There are many different conditional mental states, and different conditional speech acts [Edgington]

10. Modality / B. Possibility / 8. Conditionals / c. Truth-function conditionals

13764

Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington]

13765

'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington]

28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question

1515	Pythagoreans believe it is absurd to seek for goodness anywhere except with the gods [Iamblichus]