From Thomas Merton's loose translation, The Way of Chuang Tzu, p. 153 of my copy:
Hui Tzu said to Chuang Tzu:
"All your teaching is centered on what has no use."
"If you have no appreciation for what has no use
You cannot begin to talk about what can be used.
The earth, for example, is broad and vast
But of all this expanse a man uses only a few inches
Upon which he happens to be standing.
Now suppose you suddenly take away
All that he is not actually using
So that, all around his feet a gulf
Yawns, and he stands in the Void,
With nowhere solid except right under each foot:
How long will he be able to use what he is using?"
Hui Tzu said: "It would cease to serve any purpose."
Chuang Tzu concluded:
The absolute necessity
Of what has 'no use.' "