The second assumption holds that the elements of the game (players, strategies, pay-offs) are “common knowledge”, i.e. known to everyone, known to be known, known to be known to be known...ad infinitum. Two people with green eyes can see the colour of the other person’s eyes, not their own. A good samaritan comes into the room and announces that “at least one of you has green eyes”. The new aspect of this situation is that we have made our retaliation common knowledge by declaring there has been a strike.

Source: Mint October 19, 2016 20:03 UTC