Combining Texts

All the ideas for 'fragments/reports', 'Modal Logic within Counterfactual Logic' and 'Investigations into Logical Deduction'

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9 ideas

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
14626 In S5 matters of possibility and necessity are non-contingent [Williamson]
5. Theory of Logic / H. Proof Systems / 4. Natural Deduction
13832 Natural deduction shows the heart of reasoning (and sequent calculus is just a tool) [Gentzen, by Hacking]
10. Modality / A. Necessity / 1. Types of Modality
14625 Necessity is counterfactually implied by its negation; possibility does not counterfactually imply its negation [Williamson]
10. Modality / B. Possibility / 8. Conditionals / a. Conditionals
14623 Strict conditionals imply counterfactual conditionals: □(A⊃B)⊃(A□→B) [Williamson]
10. Modality / B. Possibility / 9. Counterfactuals
14624 Counterfactual conditionals transmit possibility: (A□→B)⊃(◊A⊃◊B) [Williamson]
10. Modality / C. Sources of Modality / 1. Sources of Necessity
14531 Rather than define counterfactuals using necessity, maybe necessity is a special case of counterfactuals [Williamson, by Hale/Hoffmann,A]
15. Nature of Minds / A. Nature of Mind / 1. Mind / d. Location of mind
5987 Alcmaeon was the first to say the brain is central to thinking [Alcmaeon, by Staden, von]
15. Nature of Minds / C. Capacities of Minds / 2. Imagination
14628 Imagination is important, in evaluating possibility and necessity, via counterfactuals [Williamson]
29. Religion / D. Religious Issues / 2. Immortality / b. Soul
24043 Soul must be immortal, since it continually moves, like the heavens [Alcmaeon, by Aristotle]