  The Vaiśeṣika system of ‘categories’ (padārtha) is an attempt to classify in a systematic way all the different types of existent. Navya-Nyāya lists seven ‘categories’ of object: substance (dravya), quality (guṇa), motion or action (karma), universal (sāmānya), particularity or differentiator (viśeṣa), inherence (samavāya), and absence (abhāva). Of these, the first six comprise the classical list of categories, found even in the Vaiśeṣika-sūtra, while the seventh (absence) is a distinctive addition by the later school. Most of these types are themselves subject to sub-division: thus, there are nine types of substance, twenty four types of quality, etc.