Pariṇāma

Pariṇāma is substantial transformation: milk becomes curd, clay becomes pot — the substance really changes. This is the causal theory of Sāṅkhya. Vedānta rejects pariṇāma as an explanation of the universe: Brahman does not transform into the world (it would alter the immutable). The Vedāntic doctrine is vivarta — appearance without real transformation, as a rope appears as a snake without becoming a snake. Distinguishing pariṇāma from vivarta is key to understanding why Śaṅkara denies change in Brahman.