Combining Texts

All the ideas for 'fragments/reports', 'Intro to 'Philosophy of Logic'' and 'A Completeness Theorem in Modal Logic'

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15 ideas

1. Philosophy / B. History of Ideas / 2. Ancient Thought

1597	Thales was the first western thinker to believe the arché was intelligible [Roochnik on Thales]

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]

9456	Modal logic is multiple systems, shown in the variety of accessibility relations between worlds [Jacquette]

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 / A. Overview of Logic / 1. Overview of Logic

9457	The two main views in philosophy of logic are extensionalism and intensionalism [Jacquette]

5. Theory of Logic / I. Semantics of Logic / 5. Extensionalism

9458	Extensionalists say that quantifiers presuppose the existence of their objects [Jacquette]

5. Theory of Logic / I. Semantics of Logic / 6. Intensionalism

9461	Intensionalists say meaning is determined by the possession of properties [Jacquette]

10. Modality / C. Sources of Modality / 5. Modality from Actuality

3013	Nothing is stronger than necessity, which rules everything [Thales, by Diog. Laertius]

19. Language / C. Assigning Meanings / 7. Extensional Semantics

9460	Extensionalist semantics forbids reference to nonexistent objects [Jacquette]

9459	Extensionalist semantics is circular, as we must know the extension before assessing 'Fa' [Jacquette]

26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / c. Ultimate substances

1494	Thales said water is the first principle, perhaps from observing that food is moist [Thales, by Aristotle]

27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement

1713	Thales must have thought soul causes movement, since he thought magnets have soul [Thales, by Aristotle]

29. Religion / A. Polytheistic Religion / 2. Greek Polytheism

1742	Thales said the gods know our wrong thoughts as well as our evil actions [Thales, by Diog. Laertius]