Tracing the Origins of Li Shizhen’s Theory “The Brain Is the Abode of the Original Spirit”—Focusing on Daoist Inner Alchemy Practices in the Tang and Song Dynasties

Li Shizhen’s theory “The brain is the abode of the original spirit” has exerted a profound influence on traditional Chinese medicine. However, there has been a long-standing academic debate regarding whether this concept originates from traditional medicine, Daoism, or Western medicine. In fact, this issue transcends the medical field and is closely linked to profound questions within Daoist culture. By examining Daoist Inner Alchemy Practices, particularly the theories of brain–spirit storage and brain physiology in Daoist Inner Alchemy Practices since the Tang and Song dynasties, as well as their impacts on traditional medical theories, this paper further demonstrates that Li Shizhen’s theory derives from Daoism.