The theories of the two truths are often associated with the interpretation made by the Sanlun 三論 （three treatises） School. As a matter of fact, however, during the Southern and Northern Dynasties, various theories on the two truths emerged within different Buddhist schools, including the Chengshi 成実 （centred on the Tattvasiddhi）, the Niepan 涅槃 （centered on the Mahāparinirvāṇa-sūtra）, the Shelun 摂論 （centered on the Mahāyāna-saṃgraha） and the Dilun 地論 （centered on the Daśabhūmikasūtra-śāstra） schools. Since the Nirvāṇa Sūtra also contains content related to the two truths, commentators on the Nirvāṇa Sūtra extensively discussed the nature of the two truths and their relationship, and formulated interpretations. For example, one theory argues that the conventional truth and the ultimate truth are equivalent, and both are mutually based on li 理 （principle）. Both “conventional truth” and the “ultimate truth” are seen as mere designatory names that are established to guide beings. Moreover, the conventional truth is considered the truth taught by people in the mundane world, while the ultimate truth is spoken by those in the transmundane world. Apart from commentaries on the Nirvāṇa Sūtra, works such as Xiao Ziliang’s 萧子良 Zayiji 雑義記 and Xiao Tong’s 萧統 Lingzhi jie erdi yi 令旨解二諦義 also discuss the two truths based on the Nirvāṇa Sūtra. Examining these materials provides insight into one aspect of the theories of the two truths during the Southern and Northern Dynasties.
