UCSB Philosophy Blog

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Tuesday, October 03, 2006

The Hardest Logic Puzzle Ever

Three gods A, B, and C are called, in some order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a completely random matter. Your task is to determine the identities of A, B, and C by asking three yes-no questions; each question must be put to exactly one god. The gods understand English, but will answer all questions in their own language, in which the words for “yes” and “no” are “da” and “ja” in some order. You do not know which word means which.[1]

[1]George Boolos (1996), p. 62.


  • At 12:56 PM, Blogger the metaphysician said…

    I recall reading about a puzzle very similar to this one, one invented by Ray Smullyan. But I don't recall the last part about not knowing the language of the gods. That certainly makes the original problem--the solution to which completely escapes me--much harder.

  • At 12:13 PM, Blogger douglys said…

    I put the solution on my blog. With an additional thesis.


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