Xiaogan Liu shows that the term wu, or “nonbeing,” is a concept particular to the Laozi and the Daoist tradition. Four philosophical senses of the concept of wu in the Laozi itself and in Wang Bi’s annotations of the Daodejing can be summarized: Wu is the source of the universe, or the state before anything has emerged. This wu relates to cosmology and has nothing to do with the affairs of the mundane world. Wu, together with you 有, expressed as both “nameless” (wuming 無名) and “named” (youming 有名), reflects the conceivability and incomprehensibility of Dao 道. In this sense, wu and you are two aspects of Dao. Neither of the two is directly related to issues of the physical or human world. Wu is a notion or phenomenon that is opposite to you in the empirical world. At this level, wu and you transform out of and into each other. These three meanings of wu belong to different realms, but Wang Bi fuses all of them into one abstract and universal concept, namely the nonbeing of Dao, which is the origin and ground of the universe and human society. Wang Bi’s theory is an early peak of abstract thought in the history of Chinese philosophy, that is both coherent and comprehensive. Liu further argues for wu’s significance in social and political life, as suggested by the Laozi’s and Wang Bi’s conception of it.