Dignaga

Dignāga (c. 480 – c. 540 CE) was an Indian Buddhist scholar and one of the Buddhist founders of Indian logic (hetu vidyā). Dignāga's work laid the groundwork for the development of deductive logic in India and created the first system of Buddhist logic and epistemology (Pramana). According to Georges B Dreyfus, his philosophical school brought about an Indian "epistemological turn" and became the "standard formulation of Buddhist logic and epistemology in India and Tibet." Dignāga's thought influenced later Buddhist philosophers like Dharmakirti and also Hindu thinkers of the Nyaya school. Dignāga's epistemology accepted only "perception" (pratyaksa) and "inference" (anumāṇa) are valid instruments of knowledge.

Dignāga was born into a South Indian Brahmin family in Simhavakta near Kanchipuram and very little is known of his early years, except that he took as his spiritual preceptor Nagadatta of the Pudgalavada school before being expelled and becoming a student of Vasubandhu.

Dignāga's epistemology holds that there are only two 'instruments of knowledge' or 'valid cognitions' (pramāṇa); "perception" (pratyaksa) and "inference" (anumāṇa). Perception is a non-conceptual knowing of particulars which is bound by causality, while inference is reasonable, linguistic and conceptual. This conservative epistemic theory was in contrast to the Nyaya school who accepted other means of knowledge such as Upamāṇa (comparison and analogy).

During Dignāga's time, the Nyaya school of Hinduism had begun to hold debates using their five-step approach to making and evaluating arguments with logic. Buddhist debaters such as Dignāga wanted to engage in these debates, and also have a way to logically evaluate arguments, but a premise such as "all dogs are mammals" proved problematic for his idealist Yogacara philosophy. Dignāga was a student of Vasubandhu, and therefore believed that "dharmas are empty." In other words, there are not universal qualities such as "dog-ness" or "mammal-ness." Such universals would have to be unchanging, and since all things are subject to change and are lacking in essential essence according to his school of philosophy, Dignāga attempted to find a way to engage in argument within the Nyaya school without positing metaphysical Universals.

...
Wikipedia