India · c. 480–540
Dignāga
Founder of Buddhist logic and epistemology
He cut the means of knowledge to perception and inference, defined perception as free of concepts, explained word meaning as exclusion (apoha), and mapped valid and invalid reasons in his ‘wheel of reasons’.
Life and thought
Dignāga (c. 480–540), born near Kāñcī in southern India, founded the Buddhist school of logic and epistemology (pramāṇa). Tradition, perhaps reliably, makes him a pupil of Vasubandhu. He spent his life debating at the monastic centres of his day and summed up his thought in the Compendium of Valid Cognition, which survives complete only in Tibetan translation.
Dignāga asked what the reliable means of knowledge are, and answered: only two, because there are only two kinds of object. Perception grasps unique, momentary particulars and is free of concepts; inference grasps general features through concepts. Everything else counts as one of these. Words, he argued, do not refer to real universals such as “cowness”; a word like “cow” works by excluding what is not-cow (apoha). In his “wheel of reasons” he tabulated which patterns of a reason’s presence and absence make an inference valid. Nyāya and Mīmāṃsā authors spent centuries answering him; Dharmakīrti refined his system.