A Zen monk related a story. “Before becoming a monk I was an English teacher in an Experimental High School near Chengdu in Southwestern China. One day I held up a walnut. “What is this?” They answered in Chinese. I wrote “walnut” and “metaphor” on the board. “This walnut is like a person I know, very hard on the outside. They are very safe and secure inside their shell. Nothing can happen to them. What is inside this shell?” “Some food,” said a boy. “How do you know?” “My mother told me.” “Do you believe everything your mother tells you?”