 Jayarāśi’s undertaking is not restricted to the examination of valid cognitive procedures, or cognitive criteria (pramāṇa) and their definitions. In the course of his work, he analyses a number of fundamental ideas and demonstrates that their definitions are inadequate and they cannot exist as understood and defined by philosophers. These include such notions as validity and nonerroneousness, sublation of previous knowledge by a subsequent experience, universals, the relation of composite wholes to their parts, production of cognitions, ontological categories such as inherence of properties in their substrata, the nature of illusion, the definition of what exists (e.g. the real object’s ability to execute causally efficient action, artha-kriyā), the nature of sense-object contact, memory and recollection, momentariness and permanence, conceptuality or conceptual state of mind, relation of the conceptual image in cognition to the external thing represented, the nature of consciousness (rejection of non-material character), rebirth and karmic retribution, causality, visible and invisible objects, absences, rules of inference etc. All these ideas, as Jayarāśi demonstrates, stand in need of proper definition and as long as we do not have them cannot be maintained in their present form.