The Lord Plato is guarding a bridge over a river when Socrates appears. Socrates begs to be allowed passage. Plato bellows " If the next thing you say is true I will allow passage, but if the next thing you say is false I will throw you in the water" Socrates being clever says; " You will throw me in the water" If Plato does indeed throw Socrates in the water, then Socrates spoke truly and shouldn't have been thrown in, but if he doesn't throw him in, Socrates spoke falsely and should have gone in! Either way Plato is stuffed!! But hang on, Plato cannot fulfil his promise, it's logically impossible, so he has no obligation to keep his promise, and assuming free will can throw Socrates in the river if he pleases. It is argued that statements about future intentions cannot have a truth or false value. Socrates saying " You will throw me in the water " is neither true or false. However Socrates could have said something avoiding future dependant language that would have avoided a dowsing in the river. What? This is taken from the book ' Paradoxes from A to Z ' by Michael Clark that I can recommend.