By differentiating the following four levels, namely Dao, De, Spirit-Illumination, and Supreme Harmony, Yan Zun is not proposing an evolutionary cosmology. Instead, he is offering a fourfold interpretation of Laozi’s Dao that can be presented as the four layers of non-being. The latter two layers, namely the Supreme Harmony and Spirit-Illumination, pertain to the phenomenon of creation and function as the material and spiritual principles of creation, respectively. Whereas the former two layers, namely the Dao and De, refer to the underlying principles of continuous creation, serving as the ultimate source and the unifying principle of continuous creation, respectively. Such an interpretation reflects Yan Zun’s grand synthesis of the thoughts implied in the Zhouyi, Zhuangzi, Laozi, etc. This synthesis has revealed the ontological depth of non-being inherent in the wisdom of Daoism. It should be regarded as the highest philosophical fusion based on Daoism during the Han Dynasty. It also constitutes, both philosophically and historically, the necessary link between Huang-Lao Daoism in the early Western Han and Wang Bi’s metaphysical Daoism in the Wei-Jin period.
L Wang (Mon,) studied this question.