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Single Idea 13693

[filed under theme 7. Existence / D. Theories of Reality / 10. Vagueness / f. Supervaluation for vagueness ]

Full Idea

In a 'supervaluation' we take a trivalent interpretation, and assign to each wff T (or F) if it is T (or F) in every precisification, leaving the third truth-value in any other cases. The wffs are then 'supertrue' or 'superfalse' in the interpretation.

Clarification

See Idea 13692 for 'precisification'

Gist of Idea

A 'supervaluation' assigns further Ts and Fs, if they have been assigned in every precisification

Source

Theodore Sider (Logic for Philosophy [2010], 3.4.5)

Book Ref

Sider,Theodore: 'Logic for Philosophy' [OUP 2010], p.83

A Reaction

[my non-symbolic summary] Sider says the Ts and Fs in the precisifications are assigned 'in any way you like', so supervaluation is a purely formal idea, not a technique for eliminating vagueness.

Related Idea

Idea 13692 A 'precisification' of a trivalent interpretation reduces it to a bivalent interpretation [Sider]

The 30 ideas with the same theme [narrowing down the vagueness]:

23541 Supervaluation can give no answer to 'who is the last bald man' [Fine,K]
9767 A vague sentence is only true for all ways of making it completely precise [Fine,K]
9770 Logical connectives cease to be truth-functional if vagueness is treated with three values [Fine,K]
9772 Meaning is both actual (determining instances) and potential (possibility of greater precision) [Fine,K]
9773 With the super-truth approach, the classical connectives continue to work [Fine,K]
9774 Borderline cases must be under our control, as capable of greater precision [Fine,K]
9049 Supervaluationism keeps true-or-false where precision can be produced, but not otherwise [Keefe/Smith]
9056 Vague statements lack truth value if attempts to make them precise fail [Keefe/Smith]
9058 Some of the principles of classical logic still fail with supervaluationism [Keefe/Smith]
9059 The semantics of supervaluation (e.g. disjunction and quantification) is not classical [Keefe/Smith]
9060 Supervaluation misunderstands vagueness, treating it as a failure to make things precise [Keefe/Smith]
21592 Supervaluation keeps classical logic, but changes the truth in classical semantics [Williamson]
21603 You can't give a precise description of a language which is intrinsically vague [Williamson]
21604 Supervaluation assigns truth when all the facts are respected [Williamson]
21607 Supervaluation has excluded middle but not bivalence; 'A or not-A' is true, even when A is undecided [Williamson]
21608 Truth-functionality for compound statements fails in supervaluation [Williamson]
21609 Supervaluationism defines 'supertruth', but neglects it when defining 'valid' [Williamson]
21610 Supervaluation adds a 'definitely' operator to classical logic [Williamson]
21613 Supervaluationism cannot eliminate higher-order vagueness [Williamson]
16208 Supervaluation refers to one vaguely specified thing, through satisfaction by everything in some range [Hawley]
16221 Supervaluationism takes what the truth-value would have been if indecision was resolved [Hawley]
13692 A 'precisification' of a trivalent interpretation reduces it to a bivalent interpretation [Sider]
13695 Supervaluational logic is classical, except when it adds the 'Definitely' operator [Sider]
13693 A 'supervaluation' assigns further Ts and Fs, if they have been assigned in every precisification [Sider]
13694 We can 'sharpen' vague terms, and then define truth as true-on-all-sharpenings [Sider]
11012 A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read]
11013 Identities and the Indiscernibility of Identicals don't work with supervaluations [Read]
11019 Supervaluations say there is a cut-off somewhere, but at no particular place [Read]
15363 In the supervaluationist account, disjunctions are not determined by their disjuncts [Horsten]
15362 If 'Italy is large' lacks truth, so must 'Italy is not large'; but classical logic says it's large or it isn't [Horsten]