When I visited the Knights and Liars Archipelago, one island I visited was called Liontruth. The tourism had a great influence on the island, so much that the knaves on the island spoke differently from most knaves. They didn't have to follow an alternating pattern, but could tell truths (like knights always do) and lie (like liars always do) in whatever pattern they wanted. The three types of inhabitants are indistinguishable by eye.

If a tourist thinks the local knaves alternate truths and lies how can a knave convince the tourist that he is not a knave?

How can a knave from this island prove himself in one statement without revealing whether he is lying or not?

How can a knight prove himself in one statement?

How can a liar prove himself in one statement?

What single statement can be said by either a knight or liar but not a knave?

1. The knave can convince the misinformed tourist that he's not a knave by saying the same thing twice, such as "I am a knave. I am a knave."

3. A knight can prove himself in one statement by saying "If I am a knave then I'm lying right now." A knave couldn't make this statement as that would be paradoxical.  A liar couldn't make the statement as it would be true regardless of the truth value of the second part.

 

Posted by Charlie on 2004-12-07 19:44:24