Vaisheshika (IAST: Vaiśeṣika; ; ) is one of the six schools of Hindu philosophy from ancient India. In its early stages, the Vaiśeṣika was an independent philosophy with its own metaphysics, epistemology, logic, ethics, and soteriology. Over time, the Vaiśeṣika system became similar in its philosophical procedures, ethical conclusions and soteriology to the Nyāya school of Hinduism, but retained its difference in epistemology and metaphysics.
The epistemology of the Vaiśeṣika school of Hinduism, like Buddhism, accepted only two reliable means to knowledge: direct observation and inference. The Vaiśeṣika school and Buddhism both consider their respective scriptures as indisputable and valid means to knowledge, the difference being that the scriptures held to be a valid and reliable source by Vaiśeṣikas were the Vedas.
The Vaiśeṣika school is known for its insights in naturalism. It is a form of atomism in natural philosophy. It postulated that all objects in the physical universe are reducible to paramāṇu (atoms), and one's experiences are derived from the interplay of substance (a function of atoms, their number and their spatial arrangements), quality, activity, commonness, particularity and inherence. Everything was composed of atoms, qualities emerged from aggregates of atoms, but the aggregation and nature of these atoms was predetermined by cosmic forces. Ājīvika metaphysics included a theory of atoms which was later adapted in the Vaiśeṣika school.
According to the Vaiśeṣika school, knowledge and liberation were achievable by a complete understanding of the world of experience.
Vaiśeṣika darshana was founded by Kaṇāda Kashyapa around the 6th to 2nd century BC.