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Single Idea 14969

[filed under theme 5. Theory of Logic / L. Paradox / 6. Paradoxes in Language / a. The Liar paradox ]

Full Idea

An example of the Strengthened Liar is the following statement SL: 'Either SL is neither-true-nor-false or it is not true'. This raises a serious problem for any theory that assesses the paradoxes to be neither true nor false.

Gist of Idea

Strengthened Liar: either this sentence is neither-true-nor-false, or it is not true

Source

Anil Gupta (Truth [2001], 5.4.2)

Book Ref

'Blackwell Guide to Philosophical Logic', ed/tr. Goble,Lou [Blackwell 2001], p.109

A Reaction

If the sentence is either true or false it reduces to the ordinary Liar. If it is neither true nor false, then it is true.

The 4 ideas from 'Truth'

14965 Truth rests on Elimination ('A' is true → A) and Introduction (A → 'A' is true) [Gupta]
14964 The Liar reappears, even if one insists on propositions instead of sentences [Gupta]
14968 A weakened classical language can contain its own truth predicate [Gupta]
14969 Strengthened Liar: either this sentence is neither-true-nor-false, or it is not true [Gupta]