Combining Texts

Ideas for 'Essays on Intellectual Powers: Conception', 'The Reality of Numbers' and 'Rationality and Logic'

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5 ideas

10. Modality / A. Necessity / 2. Nature of Necessity

11083

A sentence is necessary if it is true in a set of worlds, and nonfalse in the other worlds [Hanna]

10. Modality / A. Necessity / 5. Metaphysical Necessity

11086

Metaphysical necessity can be 'weak' (same as logical) and 'strong' (based on essences) [Hanna]

10. Modality / A. Necessity / 6. Logical Necessity

11084

Logical necessity is truth in all logically possible worlds, because of laws and concepts [Hanna]

10. Modality / A. Necessity / 7. Natural Necessity

11085

Nomological necessity is truth in all logically possible worlds with our laws [Hanna]

10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / b. Conceivable but impossible

11958

Impossibilites are easily conceived in mathematics and geometry [Reid, by Molnar]