The Brahma Suthra of Sri Vyasa Maharishi are the basis of Vedanthic philosophy, widely followed by all Hindus. The teachings of other Dharsanas, Agamas and traditions of Smartha Sampradaya, Saiva, Vaishnava and Saktha systems also contributed to the teachings of many commentators and the daily practice of religion. Several great Acharyas or teachers have written commentaries and interpretations of Hindu philosophy based on the Sruthis. We have the systems of Sankara, Bhaskara, Ramanuja, Madhva, Vishnuswami, Nimbarka, Vallabha, Chaithanya and the northern and Southern schools of Saivism including Meykandar's Saiva Siddhantha. Among them, Kevala Adhvaitha by Sri Sankara, Visishta-Advaitha by Sri Ramanuja and Dvaitha by Sri Madhva are commentaries on Brahma Suthras of Sri Vyasa and are the most popular. Sankara's teachings closely follow the traditions of Smarthas. The first systematic exponent of Advaitha is Gaudapaada, who is said to have lived in the eightth century AD. His pupil Govinda later became the teacher for Sankara. [Some Hindu historians and scholars claim Sankara lived in the sixth century BC]

The Adhvaitha system of Sri Sankara was developed as a commentary on Vyasa Maharishi's Brahma Suthra and the Vedhantha Philosophy, contributing to the vast majority of Smartha, Saiva and Saktha followers and closely following their traditions with some features of rituals, modifying the Mimamsa system. The Advaitha taught by Sankara is a rigorous, absolute one. Whatever is, is Brahman. It is absolutely homogenous by Itself. "Brahman, the Absolute, alone is real; this world is unreal; and the Jiva or individual soul is non-different from Brahman." The Atman is self evident. The atman is the basis of all knowledge. Brahman is not an object, as It is Adrishya, beyond the reach of our vision. Sankara's Supreme Brahman is Nirguna, formless, without attributes, without special characteristics, immutable and eternal. It is impersonal. It becomes a personal God or Saguna Brahman only through Its association with Maya. They are not two opposite entities.

In Advaitha philosophy, the same Nirguna Brahman appears as Saguna Brahman for the pious worship of the devotees. It is the same Truth from two different points of views. The former is transcendental and the latter is relative. The Jiva or the individual soul is relatively real. Its individuality lasts until it is bound by the unreal Upathis or limiting conditions due to Avidhyas. The Jiva identifies itself with the body, mind and the senses when it is deluded by the Avidhya or ignorance. Jiva merges one with the Brahman when it gets knowledge through annihilation of Avidhya. To Sankara, the world also is only relatively real. If you get knowledge, the Maya will vanish and the illusion of body and world will disappear. The unchanging Brahman appears like changing world through the mysterious Maya. The superimposition of the world on Brahman is due to Avidhya or ignorance as a result of the mysterious effects of Maya. In Vivartha-Vaada, the cause produces the effect without undergoing any change in itself. When Avidhya or the veil of ignorance is destroyed through knowledge of the Eternal, when Mithya-Jnana is removed by true knowledge, we shine in the Divine splendor and glory with the true vision of the Absolute.

Sri Sankara's Adhvaitha theory was a good reply to the theories of blind rituals of Poorva Mimamsa and to Buddhist teachings which were gaining acceptance in some areas. He wrote commentaries to Srimad Baghvad Gita to show Sri Krishna's opposition to blind ritualistic practices as in Mimamsa. He also opposed the passive cause and effect theories of Sankhya and Buddhist theories against Vedic Gods. In addition to the Adhvaitha philosophy and teachings on Jñana marga, Sri Sankara also established his system of devotional worship of six forms of Saguna Brahman for daily prayers to Ishta-Devatha or a personal Deity in the form of a Vigraha at homes or in Temples. He also gave us the religious practice following the Vedas and Smrithis. This was for the common people who cannot reach the high level of Jñana marga. He established four of his ashramams in the four corners of India to propagate his system of philosophy.