Solve Yes/No Logic Puzzle & Save Explorer: How?

• Mr Davis 97

Homework Statement

An explorer is captured by a group of cannibals. There are two types of cannibals--those who always tell the truth and those who always lie. The cannibals will barbecue the explore unless he can determine whether a particular cannibal always lies or always tells the truth. He is allowed to ask the cannibal exactly one question. Find a question that the explorer can use to determine whether the cannibal always lies or always tells the truth.

The Attempt at a Solution

I am not sure where to start. Is there a systematic way to formulate the appropriate question with propositional logic and truth tables, or must one just have divine inspiration?

You could always ask the cannibal whether he is a dolphin. If he says he is a dolphin then he's a liar.

But, I guess that's not the sort of question you are expected to find?

Battlemage!, Mr Davis 97 and member 587159
You could always ask the cannibal whether he is a dolphin. If he says he is a dolphin then he's a liar.

But, I guess that's not the sort of question you are expected to find?

I actually laughed on that one, but it's a correct answer.

Battlemage!