Combining Texts

All the ideas for 'works', 'Modal Logic' and 'The Language of Morals'

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10 ideas

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / b. System K

14970

Normal system K has five axioms and rules [Cresswell]

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / c. System D

14971

D is valid on every serial frame, but not where there are dead ends [Cresswell]

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / g. System S4

14972

S4 has 14 modalities, and always reduces to a maximum of three modal operators [Cresswell]

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5

14973

In S5 all the long complex modalities reduce to just three, and their negations [Cresswell]

4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula

14976

Reject the Barcan if quantifiers are confined to worlds, and different things exist in other worlds [Cresswell]

5. Theory of Logic / G. Quantification / 2. Domain of Quantification

17743

De Morgan introduced a 'universe of discourse', to replace Boole's universe of 'all things' [De Morgan, by Walicki]

7. Existence / C. Structure of Existence / 5. Supervenience / c. Significance of supervenience

16050

The goodness of a picture supervenes on the picture; duplicates must be equally good [Hare]

8. Modes of Existence / A. Relations / 4. Formal Relations / a. Types of relation

14974

A relation is 'Euclidean' if aRb and aRc imply bRc [Cresswell]

10. Modality / A. Necessity / 4. De re / De dicto modality

14975

A de dicto necessity is true in all worlds, but not necessarily of the same thing in each world [Cresswell]

22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / i. Prescriptivism

2855	In primary evaluative words like 'ought' prescription is constant but description can vary [Hare, by Hooker,B]