A local peasant Chad found himself in the position of choosing which of two sages would be the ruler of the kingdom. The two sages were named Bore and Gush. Chad knew that one of these sages always lied, and the other always told the truth. But he did not know which was which! So he thought for some time, and then asked Gush, "What would Bore say if I asked him which of you I should vote for?" to which Gush replied, "Bore would say, vote Gush!". Chad then asked Bore, "What would Gush say if I asked him which of you I should vote for?" to which Bore replied, "Gush would say, vote Gush!"
So, Chad voted for Gush, not Bore. But which was the liar?