Transformation and Modification
Vikāra means 'modification,' 'change,' or 'transformation.' In Vishishtadvaita's account of creation, the universe arises as a real vikāra of Prakṛti (primordial matter), which itself is the body (śarīra) of Brahman. This distinguishes Vishishtadvaita's pariṇāmavāda (transformation theory) from Advaita's vivartavāda (apparent transformation/superimposition theory).
Real Transformation
Rāmānuja argues for pariṇāmavāda: the world is a real transformation of Prakṛti, not an illusory appearance. Just as milk genuinely transforms into yogurt — the transformation is real, not superimposed — so Prakṛti genuinely transforms into the diverse world of matter and experience. This real transformation does not compromise Brahman's immutability, because Brahman itself does not transform; only its body (Prakṛti) does.
Brahman's Immutability Preserved
A key challenge: if Prakṛti is Brahman's body, and Prakṛti undergoes vikāra, does Brahman also change? Rāmānuja's answer: no. The soul (ātman) does not undergo the vikāras of the body even though the body is the soul's mode. Similarly, Brahman as the inner self of Prakṛti remains nirvikāra (without modification) while its body undergoes transformation.
Six Vikāras of Conditioned Existence
The Sānkhya tradition (partially incorporated into Vishishtadvaita) speaks of six vikāras of conditioned existence: birth, existence, growth, transformation, decay, and death. These apply to the body and subtle self but not to the ātman's svarūpa.