In this comparative study, the author investigated the differences between the tathāgatagarbha in the rNyingma’s teaching and Lao Tzu’s Dao based on qualitative-based interpretivism paradigm. The purpose of this paper is about decoding the concept of the tathāgatagarbha in both academy-based methodology and practitioner-oriented view, and therefore the meanings of the Dao from a new dimension will be revealed. Through this paper, readers are able to see the worldviews and the core teachings of both great wisdoms are fundamentally different, but in some parts they are mutually interpenetrated and interlaced. The analysis of this paper is determined by the examination of ancient Buddhist sutras, Daoist scriptures, scholarly periodicals, online journals, the Buddhist books written by the rNying ma masters, and the authoritative Daoist scholars in the Chinese academic circle. The results reveal the idea of the Dao in the Dao De Ching is essentially different the establishments of the fourfold dependent origination and the three verses of the Great Perfection in the tathāgatagarbha system of the rNying ma school; nonetheless, there are some complex relationships between the function of the tathāgatagarbha and the faculty of the Dao.
