The term has three definitions. First, it describes two different dimensions of

things: One is with form and the other without form. Second, it refers to two

different stages or states of a thing during its generation, existence, and demise.

You (有) refers to the state of a thing after it has come into being and before

it dies out; wu (无) refers to the state of a thing before its birth and after its

death. Third, you refers to any tangible or identifiable thing or the sum total of

such things; wu refers to the original source or ontological existence, which is

intangible and unidentifiable, and transcends all specific objects. With regard

to the third definition, some philosophers consider wu to be the original

source or ontological existence of the world, and you comes from wu; others

believe that you is fundamentally significant, and dispute the notion that you

owes its existence to wu. Despite their differences, you and wu are mutually

dependent.