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Single Idea 6006

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

Full Idea

The liar paradox of Eubulides says 'if you state that you are lying, and state the truth, then you are lying'.

Gist of Idea

If you say truly that you are lying, you are lying

Source

report of Eubulides (fragments/reports [c.390 BCE]) by R.M. Dancy - Megarian School

Book Ref

'Encyclopedia of Classical Philosophy', ed/tr. Zeyl,Donald J. [Fitzroy Dearborn 1997], p.328


A Reaction

(also Cic. Acad. 2.95) Don't say it, then. These kind of paradoxes of self-reference eventually lead to Russell's 'barber' paradox and his Theory of Types.


The 19 ideas with the same theme [problem when liars refer to themselves]:

If you say truly that you are lying, you are lying [Eubulides, by Dancy,R]
One of their own prophets said that Cretans are always liars [Anon (Titus)]
Vicious Circle: what involves ALL must not be one of those ALL [Russell]
'All judgements made by Epimenedes are true' needs the judgements to be of the same type [Russell]
The Liar makes us assert a false sentence, so it must be taken seriously [Tarski]
Tarski avoids the Liar Paradox, because truth cannot be asserted within the object language [Tarski, by Fisher]
'This sentence is false' sends us in a looping search for its proposition [Wittgenstein, by Fogelin]
If we write it as '"this sentence is false" is false', there is no paradox [Quine]
The Liar reappears, even if one insists on propositions instead of sentences [Gupta]
Strengthened Liar: either this sentence is neither-true-nor-false, or it is not true [Gupta]
The machinery used to solve the Liar can be rejigged to produce a new Liar [Hart,WD]
An infinite series of sentences asserting falsehood produces the paradox without self-reference [Yablo, by Sorensen]
The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess]
If you know that a sentence is not one of the known sentences, you know its truth [Priest,G]
There are Liar Pairs, and Liar Chains, which fit the same pattern as the basic Liar [Priest,G]
Self-reference paradoxes seem to arise only when falsity is involved [Read]
Banning self-reference would outlaw 'This very sentence is in English' [Sorensen]
Strengthened Liar: 'this sentence is not true in any context' - in no context can this be evaluated [Horsten]
The liar paradox applies truth to a negated truth (but the conditional will serve equally) [Halbach]