Feb
16
The fate of blue-eyed islanders
The blue-eyed islanders puzzle:1000 people are on an island. Some have blue eyes some have brown eyes. Those who figure out what color their eyes are leave the island at the end of the night. They live peacefully like this until a visitor mentions he met someone (no one in particular) with blue eyes. What happens?
The consequences are incredible. Apparently this is the realm of something in logic called common knowledge. (via mefi)