 This does not invalidate the yin-yang cosmological theory, which does yield important insight into the workings of nature and society. Nevertheless, cosmology cannot lay bare the highest Daoist truth, with which the sages of old were principally concerned. In Wang Bi’s reworking, wu emerges as a higher-order concept that accounts for the coming to be of qi and all qi-constituted phenomena. On He Yan’s reading, it would be appropriate to speak of “the Dao,” with the definite article; but in Wang Bi’s interpretation, Dao is entirely symbolic and any attempt at reification must be resisted. This affirms the radical transcendence or otherness of Dao as wu. At the same time, by means of the concept of “one,” Wang maintains also the unity of the Daoist world, without having to resort to the language of time and being. The idea of a single “root” of existence holds important practical implications.