Through the Logician’s Strainer: A Nyāya Technique

Abstract

The strainer (cālanī) tests the strength of a definition of a particular kind. Suppose the definition D is stated in terms of an absence, and x is a definiendum of D. The strainer collects each x-token or x-individual that dissatisfies D in a specific case. Then, all the x-individuals put together would be equivalent to the type x. Hence—one would be forced to conclude that—in a sense, x dissatisfies D. This is a case of under-application of D, since, despite being a definiendum of D, x dissatisfies D. Therefore, D would be too narrow. Similarly, the strainer may detect over-application too. By using the strainer, Raghunātha Śiromaṇi demonstrated that Gaṅgeśa’s conclusive definition of pervasion (vyāpti) had a defect, and redefined pervasion. The strainer test is based on intuitive principles. It may disqualify a definition that has an absence in its definiens. Therefore, strainer-proofing becomes an important consideration that must be borne in mind every time we formulate such a definition. © 2020, Springer Nature B.V.