Throughout Daoist history, Daoists have also developed different metaphysical views regarding the Dao. For example, while the Xuanxue thinker Wang Bi described Dao as wú (nothingness, negativity, not-being), Guo Xiang rejected wú as the source and held that instead the true source was spontaneous “self-production” (zìshēng 自生) and “self-transformation” (zìhuà 自化).Chan, Alan, "Neo-Daoism", The Stanford Encyclopedia of Philosophy (Summer 2019 Edition), Edward N. Zalta (ed.) Another school, the Chóngxuán (Twofold Mystery), developed a metaphysics influenced by Buddhist Madhyamaka philosophy.
