Vaisheshika did not stay a separate school forever. Kanada's atomism began as an independent system, but by roughly the eleventh century CE the philosopher Udayana had begun treating Vaisheshika's categories and Nyaya's logic as parts of a single integrated system rather than as two separate darshanas that happened to agree on some points, commenting on texts from both traditions and arguing their doctrines belonged together. The merger that followed folded Vaisheshika's ontology, its substances, qualities, actions and the atoms that compose material substance, into Nyaya's framework of formal inference and its categories of logical analysis, producing a single syncretic school, Nyaya Vaisheshika, in which Kanada's atomist physics supplied the objects of knowledge and Nyaya supplied the apparatus for reasoning about them soundly. The Encyclopedia of Indian Philosophies traces this synthesis forward to its most technically developed form, Gangesha's thirteenth century Tattvachintamani, the founding text of Navya Nyaya, new logic, which built an exacting formal vocabulary for analyzing inference and perception on the ontological foundation Kanada's sutra had supplied centuries earlier. Kanada's own name recedes from view in this later literature, but his six categories remain load bearing: a Naiyayika philosopher arguing about perception or inference in the thirteenth century was still, whether the terminology names him or not, reasoning about a world Kanada's atomism had first divided into substance, quality, action, generality, particularity and inherence.