Several people have asked more about my post the other day, so here is a short explanation. The Liar Paradox is a very ancient puzzle which has been reviewed, revised, and discussed by ancient and modern (e.g. Russell, Quine, Kripke, Tarski, Strawson) philosophers without producing a resolution that has satisfied everyone or even the majority. In the absence of an intellectual consensus, a few bold thinkers have claimed to have solved it. Thinking on this enigma has captured some of the best minds in history. Theophrastus, Aristotle's immediate successor, spilled much ink about the Liar Paradox. In fact, during the 14th century, John Buridan attempted to utilize the Liar Paradox to prove the existence of God with these two statements:
God exists.
None of the sentences in this pair is true.
The roots for the Liar Paradox go back to the sixth century BC when philosopher Epimenides wrote that the Cretans are always liars. Epimenides was a Cretan himself, thereby resulting in the first instance of this kind of logic loop. Later, Eubulides of Miletus, a philosopher from the fourth century BC more formally stated it when he said the following: A man says that he is lying. Is what he says true or false?
The other day, my blog contain this single statement: this blog post is false. The problem with this self-referential sentence is that if it is true, then it also has to be false. Yet, if we accept that statement as false, it means that it is true! This problem lies within attempting to assinging a mutually exclusive truth value to the statement.
Philetas of Cos (died circa 270 BC) was a well-known Greek poet (although his works no longer survive except in fragments); yet, he too spent so much time contemplating the Liar Paradox that he withered away without food or rest. According to the ancient writer Anthenaeus, his tombstone had this epitaph engraved on it:
O Stranger: Philetas of Cos am I,
'Twas the Liar who made me die,
And the bad nights caused thereby.
If you come up with a solution, please feel free to let me know!
Comments