Udayana

Udayana was a medieval Indian philosopher of the Nyaya-Vaisheshika school who produced the most sophisticated classical Indian arguments for the existence of God (Ishvara). His Nyayakusumanjali is the first systematic theistic treatise in Indian philosophy, marshalling logical arguments—from causation, order, and the nature of atoms—to establish that the universe requires an omniscient creator.

Udayana is also credited with reconciling the Nyaya and Vaisheshika schools into a unified system, and with producing a definitive refutation of Buddhist epistemology that effectively ended Buddhist philosophical dominance in India. His work on inference, universals, and the nature of knowledge represents the high-water mark of classical Nyaya logic. He remains the central figure in the Indian philosophy of religion.