All the issues explored in earlier modules of this course presuppose the possibility of distinguishing defensible knowledge from fancy or mere whim. This presupposition invites inquiry into the sources of knowledge. All Buddhists placed conﬁdence in sense perception, and most Buddhists also accepted that reasoning can yield knowledge. Where there was controversy was on how sense perception relates to reasoning. Do sense perception and logical reasoning operate on entirely different kinds of being—beings with very different properties—, or are some beings known by both sense perception and intellectual judgment? If they are entirely separate, how do reasoning and language connect to the data of the senses?
Two thinkers who dealt at length with these problems were Dignāga and Dharmakīrti, both of whom were embroiled in controversies with non-Buddhists as well as with other Buddhists. This module will draw upon their writings.
An important aspect of Dignāga and Dharmakīrti’s treatment of these problems was a discussion of the possibility of human knowledge being complemented by divine revelation. Like most Buddhists, these two Indian Buddhists argued strongly against this possibility, claiming that everything that is passed off as divine revelation is in fact the invention of human beings. If one accepts their arguments against the possibility of bolstering fallible human understandings with some sort of insight that is deemed superior to that of ordinary human beings, then what is the place of the teachings of the Buddha? Does it deserve a special place in the corpus of human literature? Is it in some way authoritative, or is it simply a set of hypotheses that each of us must test before accepting? If the latter, then why give any Buddhist teachings a privileged status; why not regard everything that is said by everyone as equally worthy of being tested in the crucible of experience and therefore equally worthy of respect? Most Buddhists were decidedly not what we would today call religious pluralists; so how did they defend their exclusion of other teachings, and was this defense rational or polemical in nature?
Finally, just as Nāgārjuna offered a radical questioning of the possibility of solving metaphysical puzzles, he also offered a radical questioning of the possibility of ﬁnding a satisfactory method of distinguishing knowledge from fancy. He, and his commentator Candrakīrti, can be seen as radical skeptics. If that is a correct reading of their stance, how can one reconcile a radical skepticism with the fundamental Buddhist claim that human beings suffer because of ignorance and they can eliminate suffering only by replacing misunderstanding with insight?