On the Vaiśeṣika account, every visible thing — a pot, a tree, a human body — is assembled from eternal atoms too small to perceive, and everything that exists can be sorted, without remainder, into a few kinds. The school takes its name from viśeṣa, "particularity", the ultimate difference that keeps each atom and each self distinct from every other. Its root text is the Vaiśeṣikasūtra, a collection of terse aphorisms ascribed to Kaṇāda.
The sūtras do not begin with physics. Their first line announces an explanation of dharma, right conduct, and the second defines it as whatever brings both prosperity in this life and the highest good. Within a few lines the text turns to listing what the world is made of: nine substances (earth, water, fire, air, ether, time, direction, the self and the mind), qualities running from colour and number to pleasure, desire and effort, and five kinds of motion. The order makes a claim: knowing correctly what there is, and how its parts hang together, is the road to release from suffering — a road that, in these sūtras, needs no God. They never mention one.
Nothing about Kaṇāda's life is on record, and his date is unknown. Most estimates place the sūtras between the sixth and the second century BCE and have the text reach its final shape in the last centuries BCE; some reference works put Kaṇāda several centuries later. The years on this page fall within that final stretch and stand for no known life. His name means "grain-eater": later writers of the school explained that he lived like a pigeon, on grains picked up from the road day by day. The Sanskrit kaṇa also means a tiny particle, and modern readers often render the name "atom-eater". Buddhist writers whose works survive in Chinese called the founder Ulūka, "owl", one who wandered at night; a later Vaiśeṣika commentator, Bhaṭṭa Vādīndra, answered that it was the god Shiva who had come as an owl to teach the sage. Another tradition makes him a member of the Kāśyapa clan.
The system that grew from the sūtras recognised six categories: substance, quality, motion, generality, particularity and inherence, the relation that binds a quality to the thing it belongs to. It accepted only two means of knowledge, perception and inference, where its neighbour Nyāya accepted four. The sūtras end as they begin, with the statement that the Vedas are authoritative.
Within the school, the sūtras were soon overshadowed. Praśastapāda's Padārthadharmasaṃgraha, an independent treatise, became the standard account of Vaiśeṣika, and later writers of the school brought God into it. Over the centuries Vaiśeṣika drew so close to Nyāya that the two were taught as one system. The sūtras themselves were handed down badly: for centuries readers knew them chiefly through the Upaskāra, the commentary of Śaṅkara Miśra, who in the judgement of later scholars worked from an imperfect copy. The oldest surviving commentary devoted to the sūtras, by Candrānanda, appeared in 1961, when Muni Jambuvijaya published it at Baroda, edited from two manuscripts. The text of the sūtras it carries differs substantially from the one read before.