 The Problem of Universally Positive Inference. There are, claim the Nyāya, patterns of legitimate inference in which the property inferred has as its extension the entire domain. Such inference are called ‘kevalānvayin’ or ‘universally positive’ (cf. TS 55). The stock Nyāya example is the inference “This is nameable, because it is knowable”, nameability being regarded as a property of everything. Another example would be “This exists because it is produced”. If such an inference is sound, then its reason property and inferred property must exemplify the pervasion relation. According to the above definition, to say that nameability pervades knowability is to say that any locus of the property absence-of-nameability is not a locus of knowability. The problem is that, since nameability is a universal property, absence-of-nameability is an uninstantiated (aprasiddha) property, and the Nyāya claim that such properties are ontologically suspect. To put it another way, the statement “any locus of the property absence-of-nameability is not a locus of knowability” includes a non-referring expression, “locus-of-absence-of-nameability” or “unnameable thing”, and hence is not truth-evaluable. The problem does not arise for all uninstantiated properties, for some, e.g. being a sky-lotus, or being a square circle, can be shown to be constructs made out of simpler instantiated properties. Thus, the statement “The square circle is circular” can be taken not as containing a non-referring expression, but as meaning “The circle is square and circular”. However, ‘unnameable (thing)’ is not decomposable into two distinct properties this way.