Combining Philosophers

All the ideas for Hermarchus, R Keefe / P Smith and Peter Unger

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23 ideas

4. Formal Logic / D. Modal Logic ML / 3. Modal Logic Systems / h. System S5
S5 collapses iterated modalities (◊□P→□P, and ◊◊P→◊P) [Keefe/Smith]
7. Existence / D. Theories of Reality / 10. Vagueness / b. Vagueness of reality
Objects such as a cloud or Mount Everest seem to have fuzzy boundaries in nature [Keefe/Smith]
7. Existence / D. Theories of Reality / 10. Vagueness / c. Vagueness as ignorance
If someone is borderline tall, no further information is likely to resolve the question [Keefe/Smith]
The simplest approach, that vagueness is just ignorance, retains classical logic and semantics [Keefe/Smith]
The epistemic view of vagueness must explain why we don't know the predicate boundary [Keefe/Smith]
7. Existence / D. Theories of Reality / 10. Vagueness / d. Vagueness as linguistic
Vague predicates lack application; there are no borderline cases; vague F is not F [Unger, by Keefe/Smith]
7. Existence / D. Theories of Reality / 10. Vagueness / f. Supervaluation for vagueness
Supervaluationism keeps true-or-false where precision can be produced, but not otherwise [Keefe/Smith]
Vague statements lack truth value if attempts to make them precise fail [Keefe/Smith]
Some of the principles of classical logic still fail with supervaluationism [Keefe/Smith]
The semantics of supervaluation (e.g. disjunction and quantification) is not classical [Keefe/Smith]
Supervaluation misunderstands vagueness, treating it as a failure to make things precise [Keefe/Smith]
7. Existence / D. Theories of Reality / 10. Vagueness / g. Degrees of vagueness
A third truth-value at borderlines might be 'indeterminate', or a value somewhere between 0 and 1 [Keefe/Smith]
People can't be placed in a precise order according to how 'nice' they are [Keefe/Smith]
If truth-values for vagueness range from 0 to 1, there must be someone who is 'completely tall' [Keefe/Smith]
How do we decide if my coat is red to degree 0.322 or 0.321? [Keefe/Smith]
9. Objects / A. Existence of Objects / 5. Simples
There are no objects with proper parts; there are only mereological simples [Unger, by Wasserman]
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
Vague predicates involve uncertain properties, uncertain objects, and paradoxes of gradual change [Keefe/Smith]
Many vague predicates are multi-dimensional; 'big' involves height and volume; heaps include arrangement [Keefe/Smith]
If there is a precise borderline area, that is not a case of vagueness [Keefe/Smith]
13. Knowledge Criteria / C. External Justification / 6. Contextual Justification / b. Invariantism
The meaning of 'know' does not change from courtroom to living room [Unger]
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
No one knows anything, and no one is ever justified or reasonable [Unger]
13. Knowledge Criteria / D. Scepticism / 4. Demon Scepticism
An evil scientist may give you a momentary life, with totally false memories [Unger]
25. Social Practice / F. Life Issues / 6. Animal Rights
Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley]