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.
Tao Te Ching 14