Dignāga

Dignāga (c. 480 – c. 540 CE) was an Indian 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 founded the school of Buddhist logic. Dignāga's thought influenced later Buddhist logicians like Dharmakirti and also Hindu thinkers of the Nyaya school. Dignāga also outlined a Buddhist epistemology (pramana), which was based on perception and inference.

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.

Philosophy

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 "the 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 structure without positing through the arguments that there is an essential "dog-ness," or what have you.