 The system that Gaṅgeśa takes over is inherited in particular from his “teacher” Udayana. In a dozen treatises, Udayana merges the separate literature and worldview of Vaiśeṣika—its advocates sometimes called “Atomists” —with Nyāya’s. Udayana also added the category of absence to the Vaiśeṣika-sūtra’s six, so that there are seven basic types of things possibly referred to in technical works as in everyday life: