Imagine an island where 100 people, all perfect logicians, are imprisoned by a mad dictator.
想像一下，有座岛上住着100位居民，他们每一个都是优秀的逻辑学家，却被一位邪恶的独裁者所监禁。
There's no escape, except for one strange rule.
唯一能逃离岛上的方法，必须符合一条特殊的规则。
Any prisoner can approach the guards at night and ask to leave.
所有人都可以在晚上去找守卫，并要求离开岛上。
If they have green eyes, they'll be released.
只要这位居民拥有绿色眼睛，就可以被释放。
If not, they'll be tossed into the volcano.
但如果不是绿色眼睛，就要被丢进火山。
As it happens, all 100 prisoners have green eyes,
碰巧的是，那100位居民都有绿色眼睛。
but they've lived there since birth, and the dictator has ensured they can't learn their own eye color.
但是自从出生以来，他们一直住在岛上，独裁者很确定，居民们都不知道自己眼睛的颜色。
There are no reflective surfaces, all water is in opaque containers,
岛上没有任何物品能够反射出自己的影像，所有的水都装在不透明的容器里，
and most importantly, they're not allowed to communicate among themselves.
最重要的是，居民之间不准互相沟通。
Though they do see each other during each morning's head count.
虽然每天早上点名时，他们会看到彼此。
Nevertheless, they all know no one would ever risk trying to leave without absolute certainty of success.
不过他们都知道，从来没有人敢冒险尝试离开，因为无法确定自己一定能成功。
After much pressure from human rights groups,
在许多人权团体的压力下，
the dictator reluctantly agrees to let you visit the island and speak to the prisoners under the following conditions:
独裁者勉强同意，让你拜访那座岛，你可以跟被监禁的居民谈话，但是必须符合以下的条件：
you may only make one statement, and you cannot tell them any new information.
你只能说一件事，而且不能告诉他们任何新的消息。
What can you say to help free the prisoners without incurring the dictator's wrath?
你要怎么说才能帮助居民获得自由，而且不会激怒独裁者？
After thinking long and hard, you tell the crowd, "At least one of you has green eyes."
经过一段时间的思考后，你告诉居民：“你们之中至少一位拥有绿色眼睛。”
The dictator is suspicious but reassures himself that your statement couldn't have changed anything.
独裁者虽然有点怀疑，但依然告诉自己：你说的话不会改变任何事情。
You leave, and life on the island seems to go on as before.
然后你离开了，岛上的生活又变得和之前一样。
