Lao Tse: The Tao Teh Ching Chapter 14
1. We look at it, and we do not see it, and we name it 'the
Equable.' We listen to it, and we do not hear it, and we name it
'the Inaudible.' We try to grasp it, and do not get hold of it, and
we name it 'the Subtle.' With these three qualities, it cannot be
made the subject of description; and hence we blend them together
and obtain The One.
2. Its upper part is not bright, and its lower part is not obscure.
Ceaseless in its action, it yet cannot be named, and then it again
returns and becomes nothing. This is called the Form of the
Formless, and the Semblance of the Invisible; this is called the
Fleeting and Indeterminable.
3. We meet it and do not see its Front; we follow it, and do not
see
its Back. When we can lay hold of the Tao of old to direct the
things of the present day, and are able to know it as it was of old
in the beginning, this is called (unwinding) the clue of Tao.