‘The School of Particularism’, listed in modern works as one of the six darśana or ‘schools of philosophy’, where it is paired with the Nyāya school. The foundational Vaiśeṣika text is Kaṇāda's Vaiśeṣikasūtra (probably a composite work, put together around the turn of the Common Era), which attempts to identify the fundamental (i.e. particular) constitutents of the material universe. The next earliest surviving Vaiśeṣika text is Praśastapāda's Padārthadharmasaṃgraha (‘Compendium of Properties of the Categories’, early 6th century ce), a discursive commentary on Kaṇāda, which gave rise to a commentarial tradition of its own. This culminated in Udayana (12th century), whose works effectively mark Vaiśeṣika's convergence with the Nyāya tradition.
A number of scholars have characterized a reconstructed early Vaiśeṣika as an incipient philosophy of nature, an attempt to enumerate and explain the fundamental, irreducible categories (padārthas) of existence, with only a limited, and incidental interest in soteriology. According to the commentators, the basic categories are substance (dravya), quality (guṇa), action/motion (karman), universals (sāmānya), particularity (viṣeṣa), and inherence (samavāya—which supports the relationship between entities). A seventh padārtha, non-existence, or absence (abhāva), was added in the 11th century ce. In the Nyāya-Vaiśeṣika, these seven were subsumed into prameya, the second category of Nyāya—the Vaiśeṣika padārthas thereby effectively providing an atomistic, mechanistic ontology for the merged tradition. See also Nyāya.