Combining Texts

All the ideas for 'Letters to Jourdain', 'Lectures on the Philosophy of (World) History' and 'A Completeness Theorem in Modal Logic'

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10 ideas

1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / e. Philosophy as reason

21753

If we look at the world rationally, the world assumes a rational aspect [Hegel]

2. Reason / A. Nature of Reason / 1. On Reason

21974

The world seems rational to those who look at it rationally [Hegel]

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 / F. Referring in Logic / 1. Naming / a. Names

8447	In 'Etna is higher than Vesuvius' the whole of Etna, including all the lava, can't be the reference [Frege]

5. Theory of Logic / F. Referring in Logic / 1. Naming / b. Names as descriptive

8448	Any object can have many different names, each with a distinct sense [Frege]

19. Language / A. Nature of Meaning / 7. Meaning Holism / a. Sentence meaning

8446	We understand new propositions by constructing their sense from the words [Frege]

19. Language / B. Reference / 4. Descriptive Reference / a. Sense and reference

8449	Senses can't be subjective, because propositions would be private, and disagreement impossible [Frege]