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Single Idea 8173

[filed under theme 5. Theory of Logic / D. Assumptions for Logic / 1. Bivalence ]

Full Idea

Two features of natural languages cause them to violate bivalence: singular terms (or proper names) which have a sense but fail to denote an object ('the centre of the universe'); and predicates which are not well defined for every object.

Clarification

Bivalence says sentences can only be 'true' or 'false'

Gist of Idea

Language can violate bivalence because of non-referring terms or ill-defined predicates

Source

Michael Dummett (Thought and Reality [1997], 4)

Book Ref

Dummett,Michael: 'Thought and Reality (Gifford Lectures)' [OUP 2006], p.47


A Reaction

If we switch from sentences to propositions these problems might be avoided. If there is no reference, or a vague predicate, then there is (maybe) just no proposition being expressed which could be evaluated for truth.


The 18 ideas with the same theme [propositions can only be true or false]:

In talking of future sea-fights, Aristotle rejects bivalence [Aristotle, by Williamson]
For Aristotle bivalence is a feature of reality [Aristotle, by Boulter]
How can the not-true fail to be false, or the not-false fail to be true? [Cicero]
Bivalence is a regulative assumption of enquiry - not a law of logic [Peirce, by Misak]
Bivalence applies not just to sentences, but that general terms are true or false of each object [Quine]
Language can violate bivalence because of non-referring terms or ill-defined predicates [Dummett]
Undecidable statements result from quantifying over infinites, subjunctive conditionals, and the past tense [Dummett]
Vagueness seems to be inconsistent with the view that every proposition is true or false [Mautner]
'Bivalence' is the meta-linguistic principle that 'A' in the object language is true or false [Williamson]
Standard disjunction and negation force us to accept the principle of bivalence [Mares]
Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares]
A third value for truth might be "indeterminate", or a point on a scale between 'true' and 'false' [O'Grady]
Deflationism must reduce bivalence ('p is true or false') to excluded middle ('p or not-p') [Engel]
No attempt to deny bivalence has ever been accepted [Sorensen]
If bivalence is rejected, then excluded middle must also be rejected [Rowlands]
The principle of bivalence distorts reality, as when claiming that a person is or is not 'thin' [Baggini /Fosl]
Bipolarity adds to Bivalence the capacity for both truth values [Morris,M]
When faced with vague statements, Bivalence is not a compelling principle [Rumfitt]