Udayana developed Nyāya-Vaiśeṣika arguments on inference, causation, selves, and the existence of God, keeping Nyāya in active debate with Buddhist philosophers.
Intellectual setting
Udayana worked in the increasingly integrated Nyāya-Vaiśeṣika tradition and engaged Buddhist accounts of persons, causation, and knowledge.
Key ideas
Theistic inference
His arguments use features of causal order and atomic organization in a Nyāya case for God.
Suppositional reasoning
He catalogued forms of tarka used to test rivals by consequences and regress.
Legacy
His arguments remained reference points for later Nyāya logic, philosophical theology, and Navya-Nyāya technical analysis.