Look at this window: it is nothing but a hole in the wall, but because of it the whole room is full of light. So when the faculties are empty, the heart is full of light.
ZhuangziWhen he tries to extend his power over objects, those objects gain control of him. He who is controlled by objects loses possession of his inner self... Prisoners in the world of object, they have no choice but to submit to the demands of matter! They are pressed down and crushed by external forces: fashion, the market, events, public opinion. Never in a whole lifetime do they recover their right mind!... What a pity!
ZhuangziAs regards the quietude of the sage, he is not quiet because quietness is said to be good. He is quiet because the multitude of things cannot disturb his quietude. When water is still, one's beard and eyelashes are reflected in it. A skilled carpenter uses it in a level to obtain a measurement. If still water is so clear, how much more are the mental faculties! The mind of the sage is the mirror of heaven and earth in which all things are reflected.
Zhuangzi