cf. Han Feizi's attack on the Confucians

The sage does not [necessarily] seek to follow the ways of the ancients, nor does he establish any fixed standards for all times. He examines things in his age and prepares to deal with them.

A farmer from Sung was cultivating his field and came across a stump. One day, he noticed a rabbit running on the field that accidentally ran into the stump, causing it to break its neck and die. After seeing that, the farmer just put away his tools and observed the stump, expecting that he would get another rabbit through the same method. But he got no more rabbits that way, and was soon regarded with ridicule by the people of Sung.

People who expect to effectively govern people in modern times through the methods of ancient kings are acting like those people who are observing stumps.