Talk:Liar paradox

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Philosophy: Logic C‑class Mid‑importance

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	Logic

False dilemma

This "Paradox" assumes that all statements are either true or false. They can also be neither, as the paradox clearly shows. JedG

False!

Speaker 1: "I am lying now",
Speaker 2: "No, you are standing up!"

Calvinball is not a paradox

I have removed the following: In Calvin and Hobbes, one rule of Calvinball is that you can't play it the same way twice. However, by following that rule, you are using that same rule twice.

Since it is not a liar's paradox, because the rule refers to the game as a whole, not to just a single rule.

Literature

Please feel free to add entries and comments (discussions elsewhere on this talkpage, please) to this list.

Beall, J. C., ed. (13 December 2007). Revenge of the liar: new essays on the paradox. Oxford University Press. ISBN 9780199233908. Retrieved 18 March 2010.

Review: Horsten, Leon (17 May 2009). "Revenge of the Liar: New Essays on the Paradox - Reviewed by Leon Horsten, University of Bristol/University of Leuven". Notre Dame Philosophical Reviews. Notre Dame, Indiana 46556: Philosophy Department, University of Notre Dame. ISSN 1538-1617. Archived from the original on 18 March 2010. Retrieved 18 March 2010.{{cite journal}}: CS1 maint: location (link)

Arthur Prior

The article says:

"But the claim that every statement is really a conjunction in which the first conjunct says this statement is true seems to run afoul of standard rules of propositional logic, especially the rule, sometimes called Conjunction Elimination, that from a conjunction any of the conjuncts can be derived. Thus, from This statement is true and this statement is false it follows that this statement is false and so we have, once again, a paradoxical (and non-conjunctive) statement. It seems then that Prior's attempt at resolution requires either a whole new propositional logic or else the postulation that the "and" in This statement is true and this statement is false is a special type of conjunctive for which Conjunction Elimination does not apply. But then we need, at least, an expansion of standard propositional logic to account for this new kind of "and".[4]"

This is an incorrect criticism since, if I'm not mistaken, conjunction elimination can only be used on a conjunction that is true. In this case the conjunction "This statement is true and this statement is false" would be false because one of the conjuncts would have to be false. Therefore, conjunction elimination cannot be used. —Preceding unsigned comment added by 70.171.20.157 (talk) 04:30, 14 December 2010 (UTC)[reply]

Technical tag

This article gets technical at points and loses clarity. Some clearer language would be helpful. —Ute in DC (talk) 22:54, 11 January 2011 (UTC)[reply]

Not a paradox

"Every man is a liar!" is similar to the "I always lie" statement they can't be true but they can be false, like in the statement "I don't always lie" could be true since in lying that he always lies it would not contradict the statement therefore the non-negative, (doesn't contain the "don't") true statement would be written as "I sometimes lie" the statement "Every man is a liar" must be false since it can't be true but wouldn't contradict itself it was false so the non-negative, true statement would be "At least the speaker (but not every man) is a liar "Props888 (talk) 01:38, 26 April 2011 (UTC)[reply]