- #1
nomadreid
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I have once again (this time in http://www.economist.com/node/2099851) come across the argument that a fuzzy logic solves the liar paradox by assigning the liar sentence a truth value N, other than T or F, with
[[A]] = N ⇒[[~A]] = N. However, I don't see that this gets around the essential point of the liar: the liar uses a predicate ~T, and the assumption of the existence of a predicate ~T leads to a contradiction, for example quickly with the Diagonal Lemma. So if you could build the liar sentence, then the fuzzy logic would be of use to not make it a paradox, granted, but you can't even build the liar sentence in the first place. What am I missing?
[[A]] = N ⇒[[~A]] = N. However, I don't see that this gets around the essential point of the liar: the liar uses a predicate ~T, and the assumption of the existence of a predicate ~T leads to a contradiction, for example quickly with the Diagonal Lemma. So if you could build the liar sentence, then the fuzzy logic would be of use to not make it a paradox, granted, but you can't even build the liar sentence in the first place. What am I missing?