>You're a traveler in a distant land which is inhabited by two races. The first race, we'll call them Glurphs, can not ever tell a lie, and the second race, we'll call them Rafas, can't seem to ever tell the truth. Being a stranger to this land you are not familiar with the ways of the people there and when you meet a group of three citizens you ask them which race they belong to.
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>The first one mumbles something that you could not understand.
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>The second one explains "He said he was a Rafa."
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>The third one retorts "You're a liar!"
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>Your problem is to figure out which race the third man belonged to.
Since nobody will ever say he is a Rafa, the second one is lying. Therefore, the accusation of the third one is true, so he is a Glurph.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
