Human nature refers to what is in people but which they cannot study or work at achieving.

• Quarreling over food and drink, having neither scruples nor shame, not knowing right from wrong, not trying to avoid death or injury, not fearful of greater strength or of greater numbers, greedily aware only of food and drink - such is the bravery of the dog and boar.
• A person is born with feelings of envy and hate. If he gives way to them, they will lead him to violence and crime, and any sense of loyalty and good faith will be abandoned.
• In order to properly understand the big picture, everyone should fear becoming mentally clouded and obsessed with one small section of truth.
• Quarreling over food and drink, having neither scruples nor shame, not knowing right from wrong, not trying to avoid death or injury, not fearful of greater strength or of greater numbers, greedily aware only of food and drink - such is the bravery of the dog and boar.
• A person is born with feelings of envy and hate. If he gives way to them, they will lead him to violence and crime, and any sense of loyalty and good faith will be abandoned.
• If the blood humor is too strong and robust, calm it with balance and harmony.
• If knowledge and foresight are too penetrating and deep, unify them with ease and sincerity.
• Music is a fantastic peacekeeper of the world, it is integral to harmony, and it is a required fundamental of human emotion.
• Human nature is evil, and goodness is caused by intentional activity.
• In antiquity the sage kings recognized that men's nature is bad and that their tendencies were not being corrected and their lawlessness controlled.