A translation in Italian was published earlier in the newspaper La Repubblica, under the title L'indovinello più difficile del mondo.
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,[3] in some order.
[4] Boolos credits the logician Raymond Smullyan as the originator of the puzzle and John McCarthy with adding the difficulty of not knowing what da and ja mean.
He explains that "the situation is enormously complicated by the fact that although all the natives understand English perfectly, an ancient taboo of the island forbids them ever to use non-native words in their speech.
A visitor to the island must ask a number of yes/no questions in order to discover what he needs to know (the specifics of which vary between different versions of the puzzle).
The puzzle is to find out which door leads to the castle by asking one of the guards one question.
Boolos states that the "first move is to find a god that you can be certain is not Random, and hence is either True or False".
One strategy is to use complicated logical connectives in your questions (either biconditionals or some equivalent construction).
The reason this works can be seen by studying the logical form of the expected answer to the question.
Another possible interpretation of Random's behaviour when faced with the counterfactual is that he answers the question in its totality after flipping the coin in his head, but figures out the answer to Q in his previous state of mind, while the question is being asked.
The change is as follows: This effectively extracts the truth-teller and liar personalities from Random and forces him to be only one of them.
However, it assumes that Random has decided to lie or tell the truth prior to determining the correct answer to the question – something not stated by the puzzle or the clarifying remark.
The original unmodified problem (with Boolos' clarifications) in this way can be seen to be the "Hardest Logical Puzzle Ever" with the most elegant and uncomplicated looking solution.
Uzquiano (2010) exploits this asymmetry to provide a two question solution to the modified puzzle.
[9][10] However, Uzquiano's own modification to the puzzle, which eliminates this asymmetry by allowing Random to either answer "ja", "da", or remain silent, cannot be solved in fewer than three questions.