"Several noble souls have taken birth in Bharat, followed the great culture of this country, and set examples to others. Sri Sankaracharya is one such great personality who spread the culture of Bharat throughout the length and breadth of the country and earned eternal fame. Adi Sankara taught the philosophy of advaita (monism). Three centuries after him came Sri Ramanujacharya, who advocated the visishtadvaita (qualified monism) system of philosophy, which emphasised bhakti (devotion) and prapatthi (surrender) to God. Two centuries after Sri Ramanujacharya, Sri Madhwacharya arrived on the scene and propagated the dvaita (dualism) system of philosophy emphasising the devotional path to the people vacillating between several systems of philosophy. However, the fundamental principle underlying all the three schools of philosophy is one and the same, that is, Atma Tattwa (Atmic principle). The advaita (non-dualistic) philosophy of Sri Sankaracharya advocates the oneness of jiva (individual soul) and Brahman (cosmic soul). The visishtadvaita philosophy of Sri Ramanujacharya presupposes that jiva and Brahman are different. Sri Madhwacharya explained that there are, in fact, three concepts, namely, dehatma bhava (body consciousness), jivatma bhava (individualised form of God) and Paramatma Bhava (the universalised soul or the Supreme self). Nobody need hold on to a particular school of thought or deride the others. The question of adhering to a particular school of philosophy depends upon the mental frame work of the individual. Sri Sankaracharya emphasised that though the cloth is of different varieties, the thread underlying the cloth is one and the same. "The cloth is made of a number of threads woven together," explained Sri Ramanujacharya. One has to recognise the underlying principle behind the three schools of philosophy,namely, the advaita, the visishtadvaita, and the dvaita.
Brahman alone is the eternal, changeless principle. That is why Sri Sankaracharya has declared, Brahma sathyam jagat mithya (Brahman alone is real, the world is illusory). All the three great acharyas,namely, Sri Sankaracharya, Sri Ramanujacharya, and Sri Madhwacharya,propagated the same principle, that is, Atma Tattwa."
Excerpts from "Who are you? I am I" - Divine Discourse by Bhagavan Sri Sathya Sai Baba, 20 October 2004.