Almost five hundred years ago, in China, a father sat down to write to his son. He wanted his son to know what had happened in his life. Many years before, when he was very young, he went to a temple and at that temple, he met a very distinguished man. He naturally paid his respects to this gentleman who in turn told him: “You are supposed to pass the imperial examination next year, why are you not studying?” Mr. Liao-Fan, for that was the father's name, asked the gentleman his name, where he was from, and how he was able to know what Mr. Liao-Fan was supposed to do. Mr. Kong, for that was the gentleman's name, told him that he knew how to predict what was going to happen, and that he was supposed to teach this art to Mr. Liao-Fan. Mr. Liao-Fan went home and being a respectful and filial son told his mother everything that it happened. His mother wisely told him: “Invite the gentleman to our house, but before we believe what people tell us, we need to first test them to make su...