Combining Texts

All the ideas for 'works', 'Letters to Jourdain' and 'Modal Logic'

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12 ideas

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / b. System K
Normal system K has five axioms and rules [Cresswell]
4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / c. System D
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
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
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
Reject the Barcan if quantifiers are confined to worlds, and different things exist in other worlds [Cresswell]
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
In 'Etna is higher than Vesuvius' the whole of Etna, including all the lava, can't be the reference [Frege]
5. Theory of Logic / F. Referring in Logic / 1. Naming / b. Names as descriptive
Any object can have many different names, each with a distinct sense [Frege]
8. Modes of Existence / A. Relations / 4. Formal Relations / a. Types of relation
A relation is 'Euclidean' if aRb and aRc imply bRc [Cresswell]
10. Modality / A. Necessity / 4. De re / De dicto modality
A de dicto necessity is true in all worlds, but not necessarily of the same thing in each world [Cresswell]
19. Language / A. Nature of Meaning / 7. Meaning Holism / a. Sentence meaning
We understand new propositions by constructing their sense from the words [Frege]
19. Language / B. Reference / 4. Descriptive Reference / a. Sense and reference
Senses can't be subjective, because propositions would be private, and disagreement impossible [Frege]
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / e. Human nature
The most important aspect of a human being is not reason, but passion [Kierkegaard, by Carlisle]