Combining Texts

All the ideas for 'Necessary Existents', 'Modal Logic within Counterfactual Logic' and 'On Sufficient Reason'

expand these ideas     |    start again     |     specify just one area for these texts

9 ideas

2. Reason / B. Laws of Thought / 1. Laws of Thought
19404 Necessities rest on contradiction, and contingencies on sufficient reason [Leibniz]
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]
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 / C. Capacities of Minds / 2. Imagination
14628 Imagination is important, in evaluating possibility and necessity, via counterfactuals [Williamson]
19. Language / D. Propositions / 3. Concrete Propositions
19216 Propositions (such as 'that dog is barking') only exist if their items exist [Williamson]
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / c. Essence and laws
19403 Each of the infinite possible worlds has its own laws, and the individuals contain those laws [Leibniz]