A Note on the Date of Udayana

Summary

This article addresses the long‑standing question of when the logician Udayana, one of the brightest figures of the Nyāya–Vaiśeṣika tradition, lived. After reviewing earlier scholarship, including attempts to place Udayana as early as the tenth century and as late as the twelfth, the author argues that Udayana most likely flourished during the first half of the eleventh century. The argument is based on internal and external evidence from Udayana’s own works and from Buddhist texts he refuted. Ratnakīrti, a Buddhist scholar whose ideas Udayana criticises in the Ātmatattvaviveka, is dated to roughly 950–1050 CE, so Udayana cannot be placed much earlier. The article examines the colophon to Udayana’s Lakṣaṇāvalī, which gives the composition date as 984 Śaka era (1062 CE), although another reading gives 976 Śaka (1054 CE). Since his later works, such as the Nyāyakandalī and Kirāṇāvalī, show familiarity with the Lakṣaṇāvalī, these treatises cannot have been completed much earlier than the mid‑eleventh century. Comparative passages between Udayana’s Ātmatattvaviveka and Buddhist treatises, and his citations of figures such as Ratnakīrti and Dipankara Atisa, further suggest that he was reacting to contemporary debates rather than those of the eighth or ninth centuries. The article also weighs evidence from Hindu and Buddhist conversion stories that Udayana recounts. He mentions prominent Buddhist philosophers whose activities fall in the tenth and eleventh centuries, implying that they were his near contemporaries. By collating these clues, the author concludes that Udayana’s period should be fixed between about 950 and 1050 CE, with the composition of the Lakṣaṇāvalī and Kirāṇāvalī falling around 1050–1060 CE. The conclusion challenges earlier attempts to date Udayana to the ninth century and stresses the importance of examining intertextual references when reconstructing intellectual history. While the evidence is fragmentary, the cumulative weight of these internal and external references points toward a high point of Udayana’s activity in the mid‑eleventh century.