To know to stop where they cannot arrive by means of knowledge is the highest attainment. Those who cannot do this will be destroyed on the lathe of Heaven.

Ch. 23, sect. 7 (tr. James Legge, 1891) | To let understanding stop at what cannot be understood is a high attainment. Those who cannot do it will be destroyed on the lathe of heaven. | Quoted as the epigraph to Ch. 3 of Ursula K. Le Guin's The Lathe of Heaven (1971), based on Legge's translation; Le Guin was subsequently informed that this was a poor translation, as there were no lathes in China in the time of Zhuangzi.