The philosopher () said, 'Man's nature is like the ()-willow, and righteousness is like a cup or a bowl. The fashioning benevolence and righteousness out of man's nature is like the making cups and bowls from the ()-willow.'

Mencius replied, 'Can you, leaving untouched the nature of the willow, make with it cups and bowls? You must do violence and injury to the willow, before you can make cups and bowls with it. If you must do violence and injury to the willow in order to make cups and bowls with it, on your principles you must in the same way do violence and injury to humanity in order to fashion from it benevolence and righteousness! Your words, alas! would certainly lead all men on to reckon benevolence and righteousness to be calamities.'

The philosopher () said, 'Man's nature is like water whirling round in a corner. Open a passage for it to the east, and it will flow to the east; open a passage for it to the west, and it will flow to the west. Man's nature is indifferent to good and evil, just as the water is indifferent to the east and west.'