The Hangman's Paradox
Here is one of my favorite paradoxes:
A hangman is stationed on a road
at the crest of a hill
. He asks each passerby where he or she is going. If the passerby lies about his destination
, he/she is hanged.
comes up to the hangman. The hangman
asks "Where are you going? Answer truthfully or face the gallows
The traveller replies, "I have come here to be put to death
The traveller was replying truthfully. So the hangman shouldn't hang him. However, he had come to the hangman to be hanged. If the hangman let him go, the traveller would be lying, therefore he should be hanged.