Ramanujacharya was a 12th-century Bhakti saint born at Sriperumbudur near modern Chennai. He is the one who opposed the Mayavada of Shankara. The philosophy of Mayavada put forward by Shankara is also known as Kevaladvaita. According to this philosophy, the Sakara form of Brahman is influenced by Maya. The true form known as Nirakara needs to take shelter of Maya to take a form.
Ramanujacharya advocated the philosophy of Vishishta Advaitavada or qualified monism. He also founded the Shrivaishnava sect. The philosophy, according to him, says that God is a Saguna Brahman. Its creative process, including all the objects, are real. This way he opposed the philosophy of Advaita given by Shankaracharya. According to him, God, matter, and soul are real where God is the inner substance and the rest are his attributes.
Vishishta Advaita also says that the universe and Brahman are equal and both are real entities just like dualism, but there is a minor difference. In this philosophy, the universe and Brahman are not separate but it is formed out of Brahman where the Brahman is a personal God with omniscient qualities who creates the world out of himself. Hence, the world bears to him the relation of the part to the whole or the relation of a qualified effect to the base and thus, the philosophy is also known as “qualified monism.”
The analogy that defines the philosophy of Vishishta Advaitavada is of “sea and wave.” Brahman is the sea and the objects of the world are waves. All waves are ultimately the sea only but as long as one sees the wave, he/she thinks it to be different from the sea. The wave is of name and form only but the ultimate reality is the sea of which the waves are a part.
Ramanujacharya considered Brahman to be Lord Vishnu or one of his avatars. According to him, Shri Vishnu has all the qualities of a personal God-omniscience, omnipotence, etc. and he is the one who has created the world out of his love for humans and he is the one who controls it as well.
In Vishishta Advaitavada, mankind enjoys a higher status as compared to that in Dualism and he is nearer to God as well. The Bhakti Saint and poet was a firm supporter of Prabattimarga or the path of self-surrender to God and advocated salvation by Bhakti.