Is time a substance?

Jain metaphysics counts substances that really exist: soul, matter, the medium of motion, the medium of rest, and space. Whether time belongs on that list is an old disagreement.

The Digambara position is that it does. Time is made of kāla-aṇu, time-atoms, one seated at every point of space throughout the Loka, and they are what makes change possible at all.

The Śvetāmbara position is more reserved. The Tattvārtha Sūtra adds time with the phrase kālaś cety eke, "and time, according to some", which records the view without endorsing it. On this account time is not an independent substance but the way change in other substances is described.

Both agree on the distinction that matters in practice. Vyavahāra kāla is conventional time, the kind measured by suns and moons and counted on this ladder, and it exists only in Samaya Kṣetra. Niścaya kāla is real duration, the bare fact that things persist and alter, and that holds everywhere.

This atlas follows the Śvetāmbara reckoning; see The Śvetāmbara reckoning.