  The later Naiyāyikas develop a remarkable theory of nonexistence. According to them, the absence of an object or feature at a particular spatial or temporal location is a state of affairs just as objective as the presence of the object or feature there. To Kanāḍa’s original list of six categories (padārtha) or types of existent, they therefore add a seventh, ‘absence’ (abhāva). This ontological doctrine is underpinned by (i) phenomenological and (ii) semantic considerations.