Pramāṇasamuccaya (Compendium of Valid Knowledge)

Dignāga's mature work, a compact verse treatise in six chapters with his own prose commentary, which turned Buddhist thought towards systematic epistemology and logic. The Sanskrit original is largely lost, and the text survives mainly in Tibetan translations. Chapter one argues that there are just two means of valid knowledge, perception and inference, because there are just two kinds of object: the bare particular and the general feature. Perception is defined as cognition free from conceptual construction, such as names and classes. Dignāga also holds that every cognition is aware of itself, and that the means of knowledge and its result are not separate. Chapters two and three treat inference for oneself and inference for others, requiring a sound reason to meet three conditions (trairūpya). Chapter four discusses examples, chapter five sets out the theory that words signify by excluding others (apoha), and chapter six criticises faulty rejoinders in debate. Its arguments set the agenda for Indian logic for centuries.

It founded the Buddhist school of logic and epistemology, and its account of perception as free from concepts remains a sharp contribution to debates about what we actually see.