Udayana (11th century)

Perhaps the most important philosopher of the Nyāya school, Udayana authored several works in the eleventh century which brought to a close the long-standing debate between Nyāya and Buddhist philosophers. The realist Nyāya philosophers had argued for the existence of an enduring self (ātman), a thesis denied by their Buddhist opponents. Such was the importance of this disagreement that it pervaded all other areas of philosophical contention between them. In the Ātmatattvaviveka (On the Discrimination of the Reality of the Self), Udayana systematically clarified the connections between the ātman debate and many other areas of philosophical dispute, with the result that, in defending ātman, he also produced a masterly defence of Nyāya realism. Udayana is also credited with giving the definitive defence of theism in the Nyāyakusumāñjali (A Handful of Nyāya-Tree Flowers).