Most people interpret Fa-tsang’s thoughts in terms of the Yuandun school (great concentration and insight) of the Huayan sect. Some may associate Fa-tsang’s thoughts with mental consciousness (alayavijnana), the classification of Buddhist teachings, the three types of character, and the original nature of the reality-realm. However, an in-depth survey of his Buddha nature is rarely seen. This study thesis thus investigates the Buddha nature in Fa-tsang’s thoughts. In his 50 Q&A, Zhiyen says, “Instead of being a separate yana, the Yuandun school is faithful to the Buddha nature and the Mahayana Mahaparinirvana.” This suggests that the Buddha nature is an ideology of the three yanas, while the Huayan sect emphasizes the dharma nature (dharmadhatu) and cause-effect (hetu-phala), the all things exist in perfect harmony and mutual interrelation sect, circumstantial reward, direct reward, and adornment. Given that the Buddha nature of Fa-tsang’s thoughts is in principle inherited from Zhiyan, this thesis focuses on the correlations between the Buddha nature and dharma nature of the Huayan sect and interprets the differences between the three yanas and another yana in terms of cause-effect. Chapter 1 Introduction describes the motivation and scope of research. Chapter 2 The Origins of Buddhist Ideology explores the debates on Buddha nature among different sects in the Sui and Tang dynasties and the inheritance of Fa-tsang. Chapter 3 and Chapter 4 investigates the Buddha nature in Fa-tsang’s thoughts in terms of the classification of the Buddhist teachings and the undivided mind and suchness of Buddhism (bhutatathata). Chapter 5 presents the conclusions of this thesis.
