The Nyayavarttika of Uddyotakara and the Vadanyaya of Dharmakirti

Summary

This article presents a critical study of two major works on Indian logic: Uddyotakara’s Nyayavarttika, a detailed prose commentary on the Nyaya-sutra, and Dharmakirti’s Vādanyāya, a Buddhist treatise on the art of debate. The author begins by situating these texts within the seventh‑century intellectual world, noting how Uddyotakara wrote his commentary to clarify and defend the Nyaya‑sutra against Buddhist critics. He outlines the structure of the Nyayavarttika, showing how it expands upon Vatsyayana’s earlier bhasya and develops a robust realist epistemology centred on perception, inference, comparison and testimony. In contrast, the Vādanyāya is introduced as part of Dharmakirti’s broader programme of Buddhist logic, aimed at exposing weaknesses in Nyaya arguments and establishing criteria for valid debate. Through detailed textual comparison, the author examines definitions of key terms such as pratyakṣa (direct cognition), anumāna (inferential knowledge), and vyapti (invariable concomitance), highlighting places where Uddyotakara and Dharmakirti agree and where they diverge. He argues that while both thinkers accept perception and inference as sources of knowledge, they differ over the role of universals: Uddyotakara insists that cognition apprehends real universals, whereas Dharmakirti denies their existence and interprets inference as a practical convention. The article also analyses the dialectical strategies in the Vādanyāya, explaining Dharmakirti’s theory of the ‘three modes’ of a valid reason (hetu) and his refutation of Nyaya fallacies. Manuscript evidence is used to show how later scholars like Udayana, Jayanta and Gangeśa synthesised elements from both traditions. By tracing intertextual references and variant readings, the author demonstrates that these works were in dialogue and that each influenced the other’s technical terminology. The article concludes that the confrontation between the Nyaya and Buddhist schools, exemplified by the Nyayavarttika and Vādanyāya, stimulated profound refinements in Indian logic. It emphasises that understanding this debate is essential for appreciating the subsequent development of Navya‑Nyaya and the enduring legacy of classical Indian philosophy. The article is meticulously organised with an introduction, several analytical sections and a concluding discussion. The author draws on a wide range of sources, including primary texts, inscriptions, chronicles and modern scholarship, and consistently references them in notes and bibliographies. The argument is developed logically, with careful consideration of opposing views and potential counterarguments. Technical terms are explained for the benefit of readers unfamiliar with the subject. Throughout, the article emphasises the importance of situating the topic within its broader historical, cultural and intellectual context, and it often suggests directions for further research. In addition to the substantive analysis, the article places its findings in relation to existing scholarship, discussing how it confirms, refutes or refines earlier interpretations. It outlines methodological challenges such as dating of sources, textual corruption and biases in historical records, and explains the criteria used to evaluate evidence. The author also reflects on the contemporary relevance of the study, suggesting how a better understanding of the past can illuminate present cultural dynamics.