Two men sat under a roof and argued about the sky. One pointed up and said the stars were falling. The other said the stars were rising and it only looked like falling because they were watching from below. They argued until morning. When the sun came up they looked outside and the stars were gone. They had spent the whole night debating something that was only visible in the dark. In the daylight the sky was empty and blue and told them nothing. They closed their books and agreed to meet again that night.