Metaphysics is a philosophical trend of thought that rose in the Three Kingdoms and the Jin Dynasty and mainly integrated Taoism and Confucianism, so it is usually called "Metaphysics in Wei and Jin Dynasties". Metaphysics was the mainstream thought that replaced Confucian classics in Wei and Jin Dynasties.

Metaphysics is a "profound knowledge" based on "ancestors telling Lao Zi and Zhuang Zi" and integrating Confucianism and Taoism. Zhouyi, Laozi and Zhuangzi are also called "San Xuan". The "metaphysics" of metaphysics comes from Laozi's thought. In the first chapter of Laozi, I said, "The Xuan is also the Xuan, which is the gate of Wan Qi". Metaphysics is the universal law "Tao" of all things in the world, which embodies the infinity and mystery of all things' changes. Metaphysical scholars interpreted The Analects of Confucius and The Book of Changes with their reformed ideas of Lao Zi and Zhuang Zi, reformed the Confucian Classics in Han Dynasty, and established the philosophical ontology of "governing by doing nothing". Confucian thoughts such as etiquette, religion, heaven and humanity are also discussed in metaphysics, but their main purpose is Taoism, that is, to emphasize sublimity is nothing, nature and inaction.