Kaṇāda founded the Vaiśeṣika school and composed the Vaiśeṣika Sūtra, developing an atomist physics on which all composite substances ultimately reduce to combinations of eternal, partless atoms of earth, water, fire, and air. He paired this with a systematic categorial ontology (padārtha) classifying everything knowable into substance, quality, action, universal, particularity, and inherence.
Intellectual setting
Kaṇāda's Vaiśeṣika Sūtra emerged within the broader landscape of classical Indian philosophical schools debating the ultimate constituents of reality, alongside rival Nyāya, Buddhist, and Jaina atomist and anti-atomist positions.
Key ideas
Atomism (paramāṇuvāda)
Kaṇāda argued that every composite, perceptible substance is made of parts, so that a chain of decomposition must terminate in partless, eternal atoms, with the four elements (earth, water, fire, air) each composed of their own qualitatively distinct type of atom.
The categorial scheme (padārtha)
Kaṇāda organized all knowable reality into a small set of fundamental categories - substance, quality, action, universal, particularity, and inherence - providing a systematic ontology used throughout later Indian philosophical debate.
Legacy
Vaiśeṣika became one of the six orthodox (āstika) schools of Hindu philosophy, and its atomism and categorial ontology were absorbed into the influential Nyāya-Vaiśeṣika synthesis that shaped Indian logic and natural philosophy for over a millennium.