Combining Texts

All the ideas for 'fragments/reports', 'Modal Logic' and 'Reply to Richards'

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11 ideas

1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems

22140

The greatest philosophers are methodical; it is what makes them great [Grice]

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]

7. Existence / A. Nature of Existence / 3. Being / d. Non-being

18933

Not-Being obviously doesn't exist, and the five modes of Being are all impossible [Gorgias, by Diog. Laertius]

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]

19. Language / F. Communication / 1. Rhetoric

9866	Gorgias says rhetoric is the best of arts, because it enslaves without using force [Gorgias, by Plato]

5864	Destroy seriousness with laughter, and laughter with seriousness [Gorgias]