The Indian Buddhist philosophers Dignāga (c. 480–540 ce) and Dharmakīrti (c. 600–660 ce) decisively influenced the course not only of Buddhist philosophy, but of Indian philosophy more generally. Having inherited an earlier philosophical tradition (the one advanced in the Buddhist Abhidharma literature) that had been largely intramural in character, Dignāga and Dharmakīrti fundamentally transformed Buddhist philosophy by advancing basically similar commitments with arguments meant to be persuasive across party lines. In doing this, they influentially theorized a family of concepts largely shared by all Indian philosophers writing in Sanskrit—a family centering on the concept of pramāṇa, which denotes a reliable way of knowing or epistemic “criterion” (as one might translate the word)—in ways that facilitated an unprecedented extent of debate among Indian philosophers of all sorts. The resultant growth in the sophistication of philosophical traditions is one of the most salient features of the mature period of classical Indian philosophy. Though there are significant differences between them, Dignāga and Dharmakīrti commonly argued in terms of a broadly empiricist sort of epistemology; this was advantageous insofar as that involves premises to which they might readily win assent, while nonetheless being conducive to the philosophical idealism they both finally upheld. Committed as they were to the basically empiricist notion that only perceptibles are finally real, both thinkers affirmed versions of the innovative sort of nominalism first introduced by Dignāga (and significantly revised by Dharmakīrti): the elusive apoha (“exclusion”) theory of meaning, which represents one of the Buddhist tradition’s signal contributions to the history of Indian philosophy. While some of Dignāga’s works were translated into Chinese and thus became influential in East Asia, none of Dharmakīrti’s was; in both India and Tibet, however, Dharmakīrti effectively eclipsed his predecessor. For generations of subsequent Indian philosophers, Dharmakīrti practically epitomized “the Buddhist position” in matters philosophical, and his works figure to this day as central to most Tibetan monastic curricula.