A man is found dead one Saturday morning. He was killed while his wife was sleeping. The wife tells the police all that she knows. She tells them that the cook was cooking breakfast, the maid was cleaning and the butler was getting the mail. The police immediately arrest the person who is responsible. Who is responsible and why?
The wife because she was sleeping, how could she know that all of that happened?!
Every day, a cyclist crosses the border between Spain and France carrying a bag. No matter how much custom officials investigate him, they do not know what he is smuggling. Do you?