I came across this puzzle a few days ago, it’s supposedly the most difficult logic puzzle in the world, made by a Harvard professor of psychology. I was unable to solve it (after several hours of scratching my head) and eventually had to concede defeat.
I did however come across a very unconventional solution to the puzzle that is acceptable based on the criteria stipulated by the creator of the puzzle, as far as I can tell that is (not the Wikipedia solution). I am however unsure whether others will agree with this assertion or not.
I’m not going to spoil it by revealing it here for those who wish to have a go at the puzzle, but for those who have already solved it or given up the solution and a detailed account of it can be found here;
“Three gods A, B, and C are called, in no particular 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.
It could be that some god gets asked more than one question (and hence that some god is not asked any question at all).
What the second question is, and to which god it is put, may depend on the answer to the first question. (And of course similarly for the third question.)
Whether Random speaks truly or not should be thought of as depending on the flip of a coin hidden in his brain: if the coin comes down heads, he speaks truly; if tails, falsely”