Vartanā
Time's function is to assist change in other things. It does not act; it lets things act.
A pot does not become old because of time, and yet without time it could not become old at all. That is vartanā: the enabling of persistence and alteration in substances that do their own changing. Time is the condition, never the agent.
Three further functions are usually listed with it. Pariṇāma, the fact of things altering; kriyā, motion; and paratva-aparatva, the older and newer relation between two things.
This is why the Samaya is defined by an atom's movement rather than by anything intrinsic to time. If time only assists change, then the smallest interval of time has to be measured by the smallest possible change.
Whether time is a substance in its own right is a question the two traditions answer differently. See Is time a substance?.
माप और संख्याएँ
| Chief function | vartanā — assisting change |
|---|---|
| Also | pariṇāma, kriyā, paratva-aparatva |
| Acts on things? | no — it enables |
| A substance? | the traditions differ |