Nyāya theory of doubt

pp. 198-219

in: Mohanty, Phenomenology and Ontology, Berlin, Springer, 1970

Abstract

The Nyāya logic contains a theory of doubt. A preoccupation with the nature, origin and structure of doubt seems out of place in a logical system inasmuch as logic has been taken to be concerned, speaking rather broadly, with formally valid thought abstracted from its psychological context. Now, Nyāya logic — in fact all Indian logic — does not conform to this conception. It is in a broad sense coextensive with, and indeed indistinguishable from, a theory of knowledge, and concerns itself with all kinds of knowledge, the non-propositional and the invalid ones not excluding. In a narrower sense it is of course a theory of inference. But even as a theory of inference, (i) it does not concern itself with the bare form, though some amount of formalism has been developed, and (ii) it does not separate logic from psychology in a way in which western formal logic has done. Consequently, it is as much interested in the psychological conditions of the origin of a certain type of knowledge, say e.g. of inference, as in the conditions of its logical validity.