The mind remains undetermined in the great Void. Here the highest knowledge is unbounded. That which gives things their thusness cannot be delimited by things. So when we speak of 'limits', we remain confined to limited things. The limit of the unlimited is called 'fullness.' The limitlessness of the limited is called 'emptiness.' Tao is the source of both. But it is itself neither fullness nor emptiness
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