Look, it cannot be seen – it is beyond form.
Listen, it cannot be heard – it is beyond sound.
Grasp, it cannot be held – it is intangible.
These three are indefinable, they are one.
From above it is not bright;
From below it is not dark:
Unbroken thread beyond description.
It returns to nothingness.
Form of the formless,
Image of the imageless,
It is called indefinable and beyond imagination.
Stand before it – there is no beginning.
Follow it and there is no end.
Stay with the Tao, Move with the present.
Knowing the ancient beginning is the essence of Tao.
The Tao abides in non-action,
Yet nothing is left undone.
If kings and lords observed this,
The ten thousand things would develop naturally.
If they still desired to act,
They would return to the simplicity of formless substance.
Without form there is no desire.
Without desire there is tranquillity.
In this way all things would be at peace.
(Lao Tzu, in http://www.chebucto.ns.ca/Philosophy/Taichi/lao.html)