Two men are sitting in a room facing each other. The first man is facing the only door, and the second man is facing the first man and he has his back to the door.
The clock in the building chimes every hour, and it is 5 minutes before the next chime. The clock is on the wall where both of them can see it.
The first man says to the second man, "When the clock chimes next, someone will come up from behind you and stab you in the back."
The second man, slightly worried, keeps talking to the first man for 5 minutes. Sure enough, the second man gets stabbed in the back when the clock chimes.
The first man had not arranged for or been informed of someone coming in and stabbing the second man. He also had no control over when the clock chimed. He was also incapable of predicting the future.
How was this?
