How Can the Explorer Save Himself from Cannibals with One Question?

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SUMMARY

The explorer can determine whether a cannibal always lies or tells the truth by asking a single question: "If I were to ask you if you are a liar, would you say yes?" This question leverages the principles of propositional logic, ensuring that a truth-telling cannibal would answer truthfully while a lying cannibal would provide a contradictory answer. The discussion highlights the importance of logical reasoning in problem-solving scenarios involving truth-tellers and liars.

PREREQUISITES
  • Understanding of propositional logic
  • Familiarity with truth tables
  • Basic problem-solving skills
  • Knowledge of logical paradoxes
NEXT STEPS
  • Research propositional logic applications in decision-making
  • Explore truth tables and their uses in logic puzzles
  • Study logical paradoxes and their implications in reasoning
  • Practice creating questions that reveal truthfulness in various scenarios
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This discussion is beneficial for puzzle enthusiasts, logic students, and anyone interested in enhancing their critical thinking and problem-solving skills.

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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.

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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?
 
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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?
 
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PeroK said:
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.
 
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