Advaita Vedanta is probably the best known of all Vedanta schools of Hinduism, the others being Dvaita and Vishishtadvaita. Advaita literally means "not two", and is often called a monistic or non-dualistic system which essentially refers to the indivisibility of the Self (Atman) from the Whole (Brahman). The key texts from which all Vedanta texts draw are the Upanishads (especially twelve or thirteen in particular), which are commentaries on the Vedas, and the Brahma Sutras (also known as Vedanta Sutras), which is in turn a work discussing the essence of the Upanishads.

Adi Shankaracharya: The Pillar of Advaita

Its first great consolidator was Shankara (788-820 CE). Continuing the line of thought of some of the Upanishadic teachers, and also that of his own teacher Gaudapada, Shankara expounded the doctrine of Advaita -- a nondualistic reality. According to Advaitins, by analyzing the three states of experience -- waking, dreaming and deep sleep -- Shankara exposed the relative nature of the world and established the supreme truth of the Advaita: the non-dual reality of Brahman in which atman (the individual soul) and Brahman (the ultimate reality expressed in the trimurti) are identified absolutely. The three states of consciousness, in fact, are subsumed into a fourth transcendental state known in the Upanishads as 'turiya.' The manifold nature of the phenomenal world and their ultimate unity is symbolized by Aum, the most sacred of Hindu mantras.

It must be noted that many of these ideas have been amply and in fact thoroughly explained in Upanishads dating back to 1000 BCE (or 1600 BCE by some estimates), such as in the Brihadaranyaka in a dialogue between Prajapati and Indra that discusses the stages of the Self and the states of consciousness; however, it was Adi (meaning First) Shankaracharya who initially gave the movement a name and went about actually spreading its teachings, systematizing his conceptions of nondualism and how to practice religion according to such ideas into coherent works like the Viveka-Chudamani (Crest-Jewel of Discrimination). He is much like Patanjali who, while not creating the idea of Raja Yoga, known in more generally in the Hindu systems of philosophy as Yoga, is credited with its spread.

Adi Shankaracharya's importance to not only Advaita thought, but Hinduism as it was subsequently practiced and understood, even by those who would not consider themselves Advaitist, cannot be stressed enough. His main works are the Brahma Bhashyas, which are commentaries on the Brahma Sutras, a commentary on the Bhagavad Gita in nondualist strains, and his own treatise on Advaita, the Viveka Choodamani/Viveka Chudamani. In addition, he is well known for propounding a system of bhakti, or selfless devotion, within an Advaitic system of philosophy, in a number of bhajans, or devotional songs, the most famous being Bhaja Govindam, Soundaryalahari and Sivanandalahari

The master's thoughts

His treatises on the Upanishads, Bhagavad Gita and Vedanta Sutras are testaments to a keen and intuitive mind that did not want to admit dogma but advocated reason. His greatest lesson was that reason and abstract philosophizing alone would not lead to moksha/liberation. It was only through selflessness and love governed by viveka (discrimination) that would see a devotee realize his inner Self. Charges that his philosophies were influenced by Buddhism are unfounded, since Shankara vehemently opposed negation of being (shunyata) and believed that the unmanifest Brahman manifested itself as Ishwara, the loving, perfect being on high who is seen by many as being Vishnu or Shiva or whatever their hearts dictate. Shankara is said to have traveled throughout India, from the south to Kashmir, preaching to the local populaces and debating philosophy (apparently successfully, though no documentation exists) with Buddhist scholars and monks along the way.

The philosophy that Shankara proposed was powerful and capitalized on years of dormant monist and mystic understandings of existence. He proposed that while the phenomenal universe, our consciousness and bodily being, are certainly experienced, they are not true reality. He did not mean to negate it, but considered that the ultimate truth was Brahman, the one divine ground that is beyond time, space and causation. Brahman is immanent and transcendent, but not merely a pantheistic concept. Indeed, while Brahman is the efficient and material cause for the cosmos, Brahman itself is not limited by its self-projection and indeed transcends all binary opposites/dualities, especially such individuated aspects as form and being, since it is incomprehensible by the human mind. We must pierce through a hazy perspectival lens to understand our true being and nature that is not perennial change and mortality but unmitigated bliss for eternity. If we are to understand the true motive force behind our actions and thoughts, we must become aware of the fundamental unity of being. How, he asks, can a limited mind comprehend the limitless Self? It cannot, he argues, and therefore we must transcend even the mind and become one with Soul-consciousness.

Subsequent Vedantins debated whether the reality of Brahman was saguna (with attributes) or nirguna (without attributes). Belief in the concept of Saguna Brahman gave rise to a proliferation of devotional attitudes and more widespread worship of Vishnu and Shiva. However, one must remember that Advaita Vedanta did not deny Saguna Brahman. Indeed, Shankara counseled worship of God in his very real forms, and has composed numerous works deploring the uselessness of intellect and calling for the true intuition of the heart to be found in love of the Lord. Advaita Vedanta is commonly misapprehended as an intellectual philosophy, whereas it is quite practical, seeking to mold the body and mind back into a purer state of being. Saguna Brahman and Nirguna Brahman are both valid forms. Perhaps Advaita is best explained by the great 19th century Advaitist Shri Ramakrishna. He compared the infinite formless 'nirguna brahman' to a vast ocean that, with the cooling breeze of a devotee's love, froze into ice in some places, developing form. This was equally real, but with the warmth of knowledge of the sun, the ice would eventually melt and the devotee would realize himself as one with ultimate, undifferentiated bliss. The Vishistadvaita and Dvaita schools believed in an ultimately saguna Brahman. They are both, like Advaita, monist and pantheistic but differ by referring to the ultimate One as God with form.

Some Teachings of Advaita Vedanta

Two other well-known and influential nondualist texts are the "Ashtavakra Gita" and "Avadhuta Gita," the former said to have been written by the Sage Ashtavakra and the latter by Sage Dattatreya.

Verse twenty-five of the Avadhuta (Ever-Free) Gita says

By such sentences as "That thou art," our own Self is affirmed. Of that which is untrue and composed of the five elements - the Sruti (scripture) says, "Not this, not this." (Neti Neti)'

This is a powerful and coherent summary of the Advaita path of Jnana Yoga, of viveka (discrimination). By peeling away the perspectival maya, or illusion, of the finite world, discriminating between what is Brahman and what is not, one comes to the truth. Brahman is not the body nor the mind. Through this process, the aspirant, or yogi, soon realizes that Brahman is all, is infinite Sacchidananda (Absolute Truth-Consciousness-Bliss) and attains moksha (liberation.)

The Impact of Advaita

Advaita Vedanta philosophy had a tremendous impact on the Hindu system of Tantra and also served to bolster Yogic (see Yoga) ideas of the ultimate Self, Brahman/Atman, being One. Advaita rejuvenated much of Hindu thought and also spurred on debate that led to the expounding of Vishishta Advaita (qualified nondualism) and Dvaita (dualism). Advaita served to bring to the fore the Hindu/Vedic philosophy whose seed can be seen in the Rig Vedic statement "Truth is One, though the sages see it as many."

Advaita and Science

Advaita may seem like a philosophy on the outside (it is practiced as a religious stream by many Hindus), but this may very well be the place where Scientific world intersects with the Spiritual world. Many of us are aware of the Plancks equation E = hv, where E = Energy of a wave, and h = Planck's constant and v = frequency of the wavelength. With the arrival of Einstein it was also established that E = mc^2 where E = energy and m = mass of a particle and c = speed of light.

When we combine the two equations, we get mc^2 = hv which gives us a very interesting relation which directly relates the mass of a particle to frequency, which means anything material has an associated wavelength namely, De Broglie waves . To sum up, matter is another form of waves which in turn is another form of energy and so on. In fact it so appears that the whole mesh of this Universe is in fact blending into that One which exhibits itself as many (namely, mass, energy, wave etc). This is where Advaita takes over to explain that everything is but the manifestation of that "One" which is omnipresent, omniscient and omnipotent. Even the concept of these fundamental waves is seen in Hindu (and consequently Advaita) belief as Aum.