A Survey and Evaluation of Diagrams for Navya-Nyāya

Navya-Nyāya, “The New Reasoning”, is a formal philosophical logic developed in India from the 11th to the 17th centuries CE, and which builds on the older traditions of Nyāya and Vaiśeṣika. Not surprisingly, Navya-Nyāya is fundamentally different from classical Western logic and from the meanings ascribed to traditional logical diagrams. For instance, although it is not entirely correct to describe Navya-Nyāya as extensional or intensional, it has an intensional flavour: abstractions are built up from concrete individuals of which we know only their possession, or not, of certain properties. In this paper we look at the implications of these semantics for the use of logical diagrams in Navya-Nyāya. We survey the use of diagrams in modern studies of Navya-Nyāya, notable examples having been produced by Wada, Das and Ganeri. We use notions of well-matchedness, iconicity and Cheng’s recent framework to analyse the effectiveness of the notations in the context of their intended purposes.