But why should a rule which had been found right in the past be subjected to fresh scrutiny? The answer is this. First, a rule once formulated in precise terms cannot adapt itself to changing circumstances. What was right in a previous age need not continue to be right in a subsequent age. This awareness that rules have to keep pace with changing times is clearly felt by Confucius. He said, ‘The Yin built on the rites of the Hsia. What was added and what was omitted can be known. The Chou built on the rites of the Yin. What was added and what was omitted can be known’ (II.23
