Vishishtadvaita (IAST ; विशिष्टाद्वैत), is a highly regarded school of Hindu philosophy belonging to the Vedanta tradition. Vedanta refers to the profound interpretation of the Vedas based on Prasthanatrayi. Vishishta Advaita, meaning "non-duality with distinctions", is a non-dualistic philosophy that recognizes Brahman as the supreme reality while also acknowledging its multiplicity. This philosophy can be characterized as a form of qualified monism, attributive monism, or qualified non-dualism. It upholds the belief that all diversity ultimately stems from a fundamental underlying unity.
Ramanuja, the 11–12th century philosopher and the main proponent of Vishishtadvaita philosophy contends that the Prasthanatrayi ("The three courses"), namely the Upanishads, the Bhagavad Gita, and the Brahma Sutras are to be interpreted in a way that shows this unity in diversity, for any other way would violate their consistency. Vedanta Desika, another major scholar who significantly helped expand the philophy of Vishitadvaita, defines Vishishtadvaita using the statement, Asesha Chit-Achit Prakaaram Brahmaikameva Tatvam: Brahman, as qualified by the sentient and insentient modes (or attributes), is the only reality.
The Vishishtadvaitic philosophy is believed to have a long history, with its earliest works no longer available. The names of these earliest philosophers are only mentioned in Ramanuja's Vedarthasamgraha. Bodhayana, Dramida, Tanka, Guhadeva, Kapardi, and Bharuci are some of the well-known philosophers in the line of those who are thought to have developed the Vishishtadvaitic system.
Bodhayana is considered to have written an extensive vritti (commentary) on the Purva and Uttara Mimamsas. Tanka is attributed with having written commentaries on Chandogya Upanishad and Brahma Sutras. Nathamuni of the ninth century AD, the foremost Acharya of the Vaishnavas, collected the Tamil prabandhas, classified them, made the redaction, set the hymns to music and spread them everywhere.