Pramāṇavārttika (Commentary on Valid Knowledge)

A verse treatise in four chapters by Dharmakīrti, presented as a commentary on Dignāga's Compendium of Valid Knowledge but in effect a new system of Buddhist epistemology. Like Dignāga, he accepts only two means of knowledge, perception and inference, matching two kinds of object: unique particulars (svalakṣaṇa), which alone are causally effective and so ultimately real, and general features constructed by thought. One chapter sets out inference for oneself and argues that a sound reason must rest on a necessary connection, either sharing an essence or being an effect, with non-perception as a third type of reason. Here he also develops the exclusion (apoha) theory of meaning, on which words pick out things by ruling out what they are not. Another chapter establishes the Buddha as a source of knowledge and defends rebirth and the path; a third treats perception, including the mind's awareness of itself; the last covers inference for others and debate. It became a central text of Tibetan monastic study.

It is the high point of Buddhist epistemology, with arguments about perception, inference, meaning and the real that still engage philosophers working on concepts and universals.