This article is intended to clarify the origin of the concept ldog pa which is original to Tibetan logic. lDog pa is a translated term from the Sanskrit vyāvṛtti—an alternate term of apoha—and is used in Tibetan texts on logic as a set of three terms (ldog pa gsum), namely: rang ldog, don ldog, and gzhi ldog.
For this purpose we may check the following three criteria in the texts of early Tibetan logic:
1. Does this text refer to three ldog pas?
2. Does this text contain a detailed discussion on the set of terms mtshan nyid, mtshon bya, and mtshan gzhi?
3. Does this text use expressions like “ngo bo gcig la ldog pa tha dad”?
The oldest text of Tibetan logic that we possess is the commentary of Dharmakīrti’s Pramāṇaviniścaya by rNgog Blo ldan shes rab (1059–1109). We find none of these three criteria in it.
The next text is the general survey of Tibetan logic Tshad ma yid kyi mun sel written by Phya pa chos kyi seng+ge (1109–1169), who was a scholar-abbot two generations later than rNgog. This text meets all three criteria. However, Phya pa uses these terms based on known meanings. Therefore, ldog pa or related expressions are developed in the time between rNgog and Phya pa by more than one unknown scholar.
