He who would concentrate himself upon life after death must first familiarise himself with life before birth.
When Chuang Tzŭ was at an interview with Duke Ai of Lu,
Who had then been dead 120 years.
the latter said, "We have many scholars, Sir, in Lu, but few of your school."
"In Lu," replied Chuang Tzŭ, "there are but few scholars."
"Look at the number who wear scholars' robes," said the Duke. "How can you say they are few?"
"Scholars who wear round hats," answered Chuang Tzŭ, "know the seasons of Heaven. Scholars who wear square shoes know the shape of Earth.
According to ancient Chinese cosmogony, "Heaven is round: Earth is square."