Ziqi of Nanguo sat leaning on his armrest, looking up to heaven and breathing gently, in a trance as if his spirit had left him. Yancheng Ziyou stood in attendance before him and said: 'What is this? Can the body really become like withered wood, and the mind like dead ashes?'

Great understanding is broad and unhurried. Little understanding is cramped and busy. Great words are clear and limpid. Little words are shrill and quarrelsome. In sleep, men's spirits go visiting. In waking hours, their bodies hustle.

Everything has its 'that' and everything has its 'this'. From the perspective of 'that,' you cannot see. But from the perspective of 'this,' you know. Therefore it is said: 'That' comes from 'this', and 'this' depends on 'that'. This is the theory of the interdependence of 'this' and 'that'.