论易学先后天阴阳理论在道教内丹学中的运用

On the Application of the Yin-yang Theory about the Former Heaven and Latter Heaven to Alchemical Daoism

在易学阴阳理论中,有以先后天分阴阳的说法,这一理论在道教内丹学中具有极其重要的价值。从生存论的角度看,人是先后天混杂的主体,阳陷阴中而为阴所耗散是其生存境遇。从功夫进路的角度看,阴中返阳,也就是使先天真阳从后天中显露出来的实践,是内丹修炼的主题。从终极境界的角度看,先后天阴阳混合无间,实现个体与太虚的合一,是内丹学追求的圆融之境。内丹学整个理论体系及修炼进程,都与《周易》所奠定的先后天阴阳理论密不可分。

In the yin-yang theory concerning Changes scholarship, there was a saying in which yin and yang were deter mined according to the division of xian tian 先天[lit. Former Heaven] and hou tian 后天[Latter Heaven]. This theory has a very significant value in Alchemical Daoism. From the perspective of existentialism, man is the subject mixed with both Former Heaven and Latter Heaven elements, in which yang is immersed in yin and dissipated by yin. The discipline of re- turning from yin to yang that is, the practice aiming to make the Former Heaven pure yang manifest out of the yin of Lat- ter Heaven is the theme of internal alchemy refinery. From the viewpoint of the ultimate realm, the fusion of yin and yang of the Former Heaven and Latter Heaven by which to realize the unity of the individual and the Great Void （tai xu 太虚） is a perfect state pursued in internal alchemy refinery. The entire theoretic system and process of practice of Alchemical Daoism were closely related to and cannot be separated from the xian tian and hou tian yin-yang theory established in Changes scholarship.