Yoichi Iwasaki

The various schools of the Indian classical philosophy have discussed the issue how we understand the meaning from an utterance. In the present paper, I analyse the ancient controversy on this issue between two schools, Naiyāyikas and Vaiśeṣikas, and attempt to show that it has two aspects of religious and epistemological natures. Vaiśeṣikas, on the ground that the process of the verbal understanding is identical with that of the inference, claim that the verbal understanding is merely a type of the inference. Naiyāyikas oppose this and assert that the former is distinct from the latter. I summarise Vaiśeṣikas’ argument into two points: (1) the similarity of the objects of the cognition and (2) that of the relations between the object and what denotes it. Naiyāyikas rejects both thesimilarities. The above discussion, which may stimulate our epistemological interest, has a close connection with the issue of scriptures. The utterance as a source of knowledge seems to have stood, in the early period, only for the scriptures, as pointed out by Hiryanna. Taking this into consideration, Vaiśeṣikas’ thesis can be understood to imply that they deny the intrinsic authority of scriptures and reduce it to the rational faculty of human beings. Naiyāyikas also deny itsintrinsic authority, but their view on the cognitive process of the verbal understanding is different from that of Vaiśeṣikas. The reason of this divergence may lie in how they treat the reliability of the speaker in respect to the cognitive process.

Since later 1990’s, a large number of researchers of information science have engaged in the systematization of credibility assessment of online information. On the other hand, Indian philosophical tradition has a 2000-year history of discussion on credibility assessment of others’ reports, which is called śabdaprāmāṇyavāda in Sanskrit. The discussions of these two disciplines share the same interest, but their methodology is substantially different: the former is based on descriptive analysis of the information that we tend to credit, and the latter gives normative formulation of information that we ought to credit. This paper tries to show that the former methodology is not sufficient for the purpose shared by information scientists. It seems necessary for information science to incorporate normative approaches to credibility, and Indian philosophy may be able to help it. I will introduce some theories of Naiyāyika-s such as Jayanta, Udayana and Gaṅgeśa for assessing the credibility of other’s reports, and examine their applicability to the contemporary issues. I will also show the possibility of getting benefit from the studies of information science to improve understanding and evaluation of Naiyāyika-s’s theories.