Truth/reality (Skt. satya, Pa. sacca) was a common topic among philosophers, ascetics and wanderers in ancient India, searching for liberation as an ultimate goal. In Buddhism, too, the word sacca has been used in various contexts represented by four truths of the nobles. The Pāli commentaries of the Theravādins not only interpret the canonical words and passages, but also classify important concepts of different meanings which are found in the Pāli Canon. Buddhaghosa in his Visuddhimagga classifies five types of sacca: vācāsacca, viratisacca, diṭṭhisacca, paramatthasacca, and ariyasacca, along with their canonical uses. This method of classification was not invented by him, as a similar classification is found in the Vimuttimagga (解脱道論). The category terms of sacca and the canonical quotations in the Vimuttimagga can be identified with the help of the Tibetan translation of the Saṃskṛtāsaṃskṛtaviniścaya. It is noteworthy that the Pāli commentaries of the Saṃyuttanikāya and the Suttanipāta added another term, brāhamaṇasacca, in their classification of sacca. More remarkably different is the commentary of the Dhammapada, which classifies it into four types including sammutisacca in contrast to paramatthasacca. It is likely that the Pāli commentaries, basically depending upon their Sīhaḷa sources, differ from the Visuddhimagga. While the Pāli commentaries actually apply these category terms in the expositions of sacca in the canon, two or three terms are sometimes given for one sacca, and even a new term like ñāṇasacca never seen in any classifications appears collaterally with them.
