Alchemy in China

The doctrinal aspects of alchemy are the main focus of many sources dating from the Tang period (seventh to tenth centuries) onward. These sources formulate their teachings and practices by borrowing the language and the abstract emblems of correlative cosmology, a comprehensive system designed to explicate the nature and properties of different domains—primarily the cosmos and the human being—and the relations that occur among them. The main work that reflects these changes and provides them with textual authority is the Zhouyi cantong qi (Token of the Agreement of the Three According to the Book of Changes; the "three" mentioned in the title are, according to some commentaries, Daoism, cosmology, and alchemy). Virtually the entire alchemical tradition from the Tang period onward acknowledges this text as its most important scriptural source. Despite this, the Cantong qi does not primarily deal with either waidan or neidan and only occasionally alludes to both of them. Its main purpose is to illustrate the nonduality of the Dao and the cosmos; the task of explicating the details of this doctrinal view, and of applying it to waidan and neidan, is left to the commentaries and to a large number of related texts.

The emblems of correlative cosmology—typically arranged in patterns that include Yin and Yang, the five agents (wuxing), the eight trigrams and the sixty-four hexagrams of the Book of Changes (Yijing), and so forth—play two main roles closely related to each other. First, they illustrate the relation between unity, duality, and the various other stages of the propagation of Original Pneuma (yuanqi) into the "ten thousand things." In this function, cosmological emblems serve to show how space, time, multiplicity, and change are related to the spacelessness, timelessness, nonduality, and constancy of the Dao. For instance, the Cantong qi describes the five agents (which define, in particular, the main spatial and temporal coordinates of the cosmos) as unfolding from the center, which contains them all, runs through them, and "endows them with its efficacy." In their second role, the emblems of the cosmological system are used to formulate the relation of the alchemical practice to the doctrinal principles. For instance, the trigrams of the Book of Changes illustrate how the alchemical process consists in extracting the pre-cosmic Real Yin (zhenyin) and Real Yang (zhenyang) from Yang and Yin as they appear in the cosmos, respectively, and in joining them to produce an elixir that represents their original oneness (Pregadio, 2000, pp. 182–184).

In the traditions based on the Cantong qi, alchemy is primarily a figurative language to represent doctrinal principles. The waidan process loses its ritual features, and the compounding of the elixir is based on two emblematic metals, mercury and lead. The refined states of these metals—respectively obtained from cinnabar and from native lead—represent Yin and Yang in their original, pre-cosmic state, and their conjunction produces an elixir whose properties are said to be equivalent to Pure Yang. The central role played by cosmology in these waidan traditions is reflected in two works related to the Cantong qi, which respectively state that "compounding the Great Elixir is not a matter of ingredients, but always of the Five Agents," and even that "you do not use ingredients, you use the Five Agents."