Vishishtadvaita philosophy classifies prameya (what is known) into two main categories as dravya (subject or matter) and adravya. Of these dravya is not only the material cause but also serves as the locus of change.
There are six dravyas – prakriti, kala, dharma bhuta jnana, nityavibhuti, jiva and Ishvara.
Again a dravya as an attribute alone, is subject to change, and, as substantive element, does not undergo any change. Ishwara is a dravya and the world of sentient and insentient matter serves as his attributes.
Ishwara and Jiva viewed as substantive elements are not subject to any modification but prakriti, kala, dharmabhutajnana and nithya vibhuti, as attributive elements, undergo change.