  Philosophers deployed these ideas in (1) the yin-yang cosmology of the Book of Changes or Yi jing, (2) theories of correlative correspondence between heaven, earth and humanity as a shared representation of cosmic order, and (3) the idea of a “classic” or “canon” as the founding text of a textual lineage. The authors of the first medical classic, the Yellow Emperor’s Classic of Internal Medicine (Huang Di neijing), also deployed these concepts, in particular in models of the human body as a yin-yang and Five Agent microcosm of the cosmos.