One day, Duke Huan of the state of Qi was reading the works of past sages.
Lun Bian, a wheelwright, believed these books were merely the dross left by the ancients.
To illustrate his point, he explained: "It is like crafting a wheel. If you work too hastily, the mortise and tenon will be too loose, and the wheel will lack firmness. If you work too slowly, they will be too taut and will not fit together. The action must be neither too fast nor too slow, achieving a perfect balance. The true ingenuity of craftsmanship cannot be fully captured in words; it must be sensed through insight and experience. Herein lies its subtlety. I cannot impart this skill to my son, nor can he receive it from me. The ancients have passed away, and with them perished the knowledge that could not be taught. Therefore, what remains in these books can only be dross."