The Fork in the Road - Answer

The logician points to one of the roads and says to the native, "If I were to ask if this road leads to the village, would you say 'yes'?"
The native is forced to give the right answer, even if he is a liar!

If the road does lead to the village, the liar would say, "No" to the direct question, but as the question is put, he lies and says he would reply, "Yes". Thus the logician can be certain that the road does lead to the village, whether the respondent is a trugh-teller or a liar. On the other hand, if the road actually does not go to the village, the liar is forced in the same way to say, "No" to the question.

arrow