Kaṇāda

Kaṇāda authored the Vaiśeṣika-sūtra, the root text of the Vaiśeṣika darśana, one of the six orthodox schools. He analyzed the world into a small set of categories (substance, quality, action, universal, particular, inherence) and argued that material objects are built from indivisible atoms (aṇu) — an early and influential naturalist-realist metaphysics that later fused with the logic-epistemology school of Nyāya into combined Nyāya-Vaiśeṣika. His dates are uncertain; scholars variously place the sūtra between roughly the 2nd c. BCE and the early centuries CE, and his biography is essentially unknown.