Combining Texts

All the ideas for 'Locke on Essences and Kinds', 'Summula philosophiae naturalis' and 'A Completeness Theorem in Modal Logic'

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11 ideas

4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
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
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
The variable domain approach to quantified modal logic invalidates the Barcan Formula [Kripke, by Simchen]
The Barcan formulas fail in models with varying domains [Kripke, by Williamson]
7. Existence / E. Categories / 5. Category Anti-Realism
Ockham was an anti-realist about the categories [William of Ockham, by Pasnau]
9. Objects / C. Structure of Objects / 4. Quantity of an Object
Ockham says matter must be extended, so we don't need Quantity [William of Ockham, by Pasnau]
Matter gets its quantity from condensation and rarefaction, which is just local motion [William of Ockham]
9. Objects / D. Essence of Objects / 13. Nominal Essence
If kinds depend only on what can be observed, many underlying essences might produce the same kind [Eagle]
Nominal essence are the observable properties of things [Eagle]
Nominal essence mistakenly gives equal weight to all underlying properties that produce appearances [Eagle]
26. Natural Theory / B. Natural Kinds / 4. Source of Kinds
Kinds are fixed by the essential properties of things - the properties that make it that kind of thing [Eagle]