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Single Idea 9056
[filed under theme 7. Existence / D. Theories of Reality / 10. Vagueness / f. Supervaluation for vagueness
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Full Idea
The supervaluationist view of vagueness proposes that a sentence is true iff it is true on all precisifications, false iff false on all precisifications, and neither true nor false otherwise.
Clarification
'Precisification' is an American word meaning 'making more precise'
Gist of Idea
Vague statements lack truth value if attempts to make them precise fail
Source
R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3)
Book Ref
'Vagueness: a Reader', ed/tr. Keefe,R /Smith,P [MIT 1999], p.23
A Reaction
This seems to be just a footnote to the Russell/Unger view, that logic works if the proposition is precise, but otherwise it is either just the mess of ordinary life, or the predicate doesn't apply at all.
The
17 ideas
from R Keefe / P Smith
9049
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Supervaluationism keeps true-or-false where precision can be produced, but not otherwise
[Keefe/Smith]
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9050
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A third truth-value at borderlines might be 'indeterminate', or a value somewhere between 0 and 1
[Keefe/Smith]
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9044
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If someone is borderline tall, no further information is likely to resolve the question
[Keefe/Smith]
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9048
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The simplest approach, that vagueness is just ignorance, retains classical logic and semantics
[Keefe/Smith]
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9045
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Vague predicates involve uncertain properties, uncertain objects, and paradoxes of gradual change
[Keefe/Smith]
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9047
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Many vague predicates are multi-dimensional; 'big' involves height and volume; heaps include arrangement
[Keefe/Smith]
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9053
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If there is a precise borderline area, that is not a case of vagueness
[Keefe/Smith]
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9055
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The epistemic view of vagueness must explain why we don't know the predicate boundary
[Keefe/Smith]
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9056
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Vague statements lack truth value if attempts to make them precise fail
[Keefe/Smith]
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9058
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Some of the principles of classical logic still fail with supervaluationism
[Keefe/Smith]
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9059
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The semantics of supervaluation (e.g. disjunction and quantification) is not classical
[Keefe/Smith]
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9060
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Supervaluation misunderstands vagueness, treating it as a failure to make things precise
[Keefe/Smith]
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9061
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People can't be placed in a precise order according to how 'nice' they are
[Keefe/Smith]
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9062
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If truth-values for vagueness range from 0 to 1, there must be someone who is 'completely tall'
[Keefe/Smith]
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9063
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How do we decide if my coat is red to degree 0.322 or 0.321?
[Keefe/Smith]
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9064
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Objects such as a cloud or Mount Everest seem to have fuzzy boundaries in nature
[Keefe/Smith]
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9065
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S5 collapses iterated modalities (◊□P→□P, and ◊◊P→◊P)
[Keefe/Smith]
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