 For Śrīharṣa, without any adequate uniform and informative characterization of the distinctive mark X, the definition of knowledge as proper circumscription of the object ought to be rejected (for other objections that he offers, see Ganeri 2016). This charge seems to be getting at something general about a class of different approaches towards defining knowledge. Several contemporary theories of knowledge involve a conception of knowledge as involving a discriminatory capacity of some kind. Take, for instance, the relevant alternatives theory which says that in order to know a proposition P, an agent must be able to rule out relevant possibilities where P is false (Stine 1976; Goldman 1976; Dretske 1981; Lewis 1996). However, as it turns out, which possibilities count as relevant will vary from one scenario to another, and perhaps also from one context of knowledge-attribution to another. In particular cases, we might indeed be able to tell whether a certain alternative counts as relevant or not. But it is unclear that we could systematize these intuitions enough to produce a single unified criterion of relevance; or, even if we did manage to do so, it is unclear whether such a criterion would be informative enough to generate predictions about every possible scenario. Thus, once again, Śrīharṣa’s worry generalizes.