  The six impediments are (1) ‘non-plurality’—a genuine universal must be plurally instantiated; (2) ‘equipollence’ (tulyatva)—two co-extensive properties cannot both be genuine universals; (3) ‘cross-connection’ (saṃkara)—two genuine universals must not partially overlap; (4) ‘regress’—a property like universality cannot itself be a universal, on pain of infinite regress (universality-hood, etc. etc.); (5) a property like differentia-hood cannot be a genuine universal, for by definition the basic differentia share no common universal property; (6) a property like inherence-hood cannot be a universal, since it does not inhere in its loci. Of these six, the last three are there basically to maintain the internal consistency of the Vaiśeṣika system, and the first is a straightforward consequence of the definition of a universal. It debars a singly-instanced properties such as space-hood from the status of genuine natural kind, perhaps motivated by the thought that the very nature of a universal consists in its grounding judgements of the form “x is of the same kind as y”, which presuppose that there are at least two entities.