Tao Te Ching · Ch. 11

三十輻,共一轂,當其無,有車之用。埏埴以為器,當其無,有器之用。鑿戶牖以為室,當其無,有室之用。故有之以為利,無之以為用。

Sān shí fú, gòng yī gū, dāng qí wú, yǒu chē zhī yòng. Shān zhí yǐ wéi qì, dāng qí wú, yǒu qì zhī yòng. Záo hù yǒu yǐ wéi shì, dāng qí wú, yǒu shì zhī yòng. Gù yǒu zhī yǐ wéi lì, wú zhī yǐ wéi yòng.

Thirty spokes converge at a single hub — it is the empty space at the center that makes the wheel useful. Clay is shaped into a vessel — it is the hollow inside that makes the vessel useful. Doors and windows are cut into walls to make a room — it is the empty space within that makes the room useful. Therefore, what is present gives benefit, but what is absent gives usefulness.

— Tao Te Ching 11

Source: Wang Bi edition (Chinese) + Hanyu Pinyin transliteration