Is the following sentence true or false: ‘This sentence is false.’? If it’s true, then what it’s asserting must be the case. But it’s asserting that it’s false; so, it must be false. OK, well that’s weird; it must be false then. But if it’s false, then what it’s asserting must not be the case, and it’s asserting that it’s false. So it must not be the case that it’s false, meaning that it’s true! Here we then have a sentence which must be true if it’s false, and false if it’s true: what a riddle!
Would it help to say that the sentence is nonsense, or ‘gibberish’? Well, it doesn’t look like gibberish, but even if it is, the problem still remains. For, as the rhyme says: nonsense is not true. So if the sentence does fail to make sense, then it’s not true, which means that it is true! This sentence owes to the ancient Greek philosopher Epimenides (6th or 7th century BC), who supposedly said that all people from Crete are liars even though he was from Crete himself! | |||