The Categories of the Real (Padārthas of Vaiśeṣika)

The Vaiśeṣika school set out to catalogue reality exhaustively: every existing thing, it held, falls under one of a small set of ultimate categories — substances (including atoms of earth, water, fire, and air, plus space, time, soul, and mind), the qualities that inhere in them, their motions, the universals they share, the ultimate particulars that distinguish them, and the relation of inherence that binds quality to substance. A seventh, absence, was added later. Paired with its atomism — the world built from indestructible point-particles — this is one of classical India's boldest attempts at a complete metaphysics of nature.