This paper discusses Mou Zongsan’s interpretation of Tiantai Zhi-yi’s concept of “the Extinction of Un-Extinction” as treated in his book Buddha Nature and Perfection of Wisdom. At the outset, Mou Zongsan’s presentation of Tiantai Zhi-yi’s original insights is introduced and subsequently, his understanding of Zhi-yi’s idea of “the Extinction of Un-Extinction” is analyzed. The paper then concludes with a critical reflection upon Mou Zongsan’s interpretation of “the Extinction of Un-Extinction”. In this paper, I attempt to point out that the concept of “the Extinction of Un-Extinction” is meant to cohere with Tiantai’s theoretical structure of the “Consummate Teaching” and furthermore has its own inherent presupposetion -- it appears as though Zhi-yi gives rise to the viewpoint of consummate teaching first, and thereupon develops his interpretation of “the Extinction of Un-Extinction” as one of the necessary conditions of the “Consummate Teaching.” Discord with Mou Zongsan’s interpretation, this paper also examines the validity of the claim that “Vexation is Bodhi” belongs to the very same theoretical domain as “the Extinction of Un-Extinction.” Doubt is raised over whether sayings such as “Vexation is Bodhi” or “the Extinction of Un-Extinction” could rightfully be considered a “Consummate and Truthful Teaching.” For instance, other Mahayana sutras treat this claim as being merely a kind of Flexible Measures” intended to cure mental afflictions. Moreover, such a temporary treatment tends to have negative effects if misunderstood or applied inappropriately.
