"The Vaiśeṣika system has categories not only for space-time-matter but also for attributes related to perception of matter. It starts with six categories (padārthas) that are nameable and knowable, asserting that nothing beyond these six is necessary."
January 1, 1970
https://en.wikiquote.org/wiki/Vai%C5%9Be%E1%B9%A3ika_S%C5%ABtra