Puzzles
Three caskets, three inscriptions, and at most one is telling the truth
A gold casket reads: 'The portrait is in this casket.' A silver casket reads: 'The portrait is not in this casket.' A lead casket reads: 'The portrait is not in the gold casket.' You're told that at most one of the three inscriptions is true. Which casket holds the portrait?
Reveal the answer
The portrait is in the silver casket. If the gold inscription were true, the silver and lead inscriptions would also both be true, giving three truths instead of one. Checking each case shows only 'portrait in silver' leaves exactly one true statement, the lead casket's. Raymond Smullyan adapted the puzzle from the casket riddle in Shakespeare's The Merchant of Venice.
— Raymond Smullyan, What Is the Name of This Book? — 1978
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