一个哲学悖论问题
you are visiting a foreign country inhabited only by knaves and knights;knaves always lie and knights tell the truth,you come to a fork in the road,where one branch leads to the capital and other does not.an inhabitant,kitty,is passing by,and will answer any question with "yes"or "no",but you can just ask one question.what one yes-or-no question you should ask kitty to determine which branch leads to the capital?
意思就是
就是你去一个国家,这个国家就只住着狡猾的人和骑士,狡猾的人专门说谎,骑士通常是讲真话.你到了一个分叉路口,一边是通往这个国家的首都,一边不是.你碰到一个路人,你可以问她任何一个用yes或no回答的问题（只能问一个）.
--