Today I began reading Gaudapada's Karika on the Mandukya Upanishad, with commentary by Adi Shankara. This book is really a double commentary on the Mandukya Upanishad. I've had this book in the drawer for some time, but found the chance to devote some time to it this week.
Although the language was archaic, and contained much Sanskrit, I was deeply impressed with the clarity which both Gaudapada and Shankara explained the chief tenets of Advaita Vedanta, through commentary on the Upanishadic text. There is also a presentation of the original Upanishad in terms of Advaita Vedanta philosophy.
One thing that particularly took my interest was the detailed explanation of the sacred syllable "AUM". Some commentary was given on its importance etc., and a break down of the three letters A, U, M, with meanings (akin to the three states of consciousness, three universal forces, and other three-combinations).
There was advice given at one point on meditating on the syllables A-U-M in turn (or 'by quarters'), or separately, and how they relate to external (gross), internal (subtle, dream) and pure consciousness realms.
In my opinion, it would seem that AUM may be used (and has indeed been used) as a portal into "consciousness only" via:
1. Use of AUM as a concentration practice via attention on the sound
2. Mindfulness of the sound first vocally, then silently (as per mantra yoga)
3. Following the sound to it's finish into silence and/or resting in the gap before the next sound.
4. Ultimately resting in the silence, and moving to "I-am-ness" or consciousness only (as a natural progression).
(5) Natural unactioned transition to Turiya (4th State).
This would be of particular usefulness to auditory-sensitive practitioners.
Gaudapada Karika Explanation
AUM should be known quarter by quarter. There is no doubt that the quarters are the same as the letters. Having understood AUM quarter by quarter, one should not think of anything else.
The mind should be concentrated on Aum. Aum is the fearless Brahman. He who is always absorbed in Aum knows no fear whatever.
Aum is verily the Lower Brahman. It is also stated to be the Higher Brahman. Aum is beginningless and unique. There is nothing outside it. It is unrelated to any effect and is immutable.
Aum is, indeed, the beginning, middle, and end of all things. He who has realized Aum as immutable immediately attains the Supreme Reality.
Know Aum to be Isvara, ever present in the hearts of all. The calm soul, contemplating Aum as all-pervading, does not grieve.
One who knows Aum, which is soundless and also endowed with infinite sounds, which is all good and the negation of duality, is a real sage, and none other. (GK 1.24-29)
Commentary by Shankaracharya
Those who have realized Brahman, the Highest Reality, merge the self in Turiya because they have transcended the notion of cause and effect, which inheres in the third quarter of Atman. They are not born again; for they have realized their identity with the causeless Turiya. The illusory snake which has merged in the rope as a result of discrimination between the snake and the rope, does not reappear. Students of dull or mediocre mind who have renounced the world and are endowed with spiritual virtues should meditate on the common features of the sounds of AUM and the quarters of Atman, as explained before. Thus, proceeding step by step, they ultimately realize Turiya, devoid of any state or sound, and attain the Highest Goal.
Swami Sivananda, The Divine Life Society, India, 1992, pp94-99.
OM consists of three letters: 'A', 'U' and 'M'. It signifies the three periods of time, the three states of consciousness, the entire existence. 'A' is the waking state or Virat and Visva. 'U' is the dreaming state of Hiranyagarbha and Taijasa. 'M' is the sleeping state or Isvara and Prajna. Study the Mandukyopanishad in detail in order to understand the meaning of OM.
Good notes here:
A few notes from the International Journal of Yoga:
Among many symbols used, Om is one of the fundamental symbols used in the yoga tradition.
REFERENCES IN THE UPANISHADS
Om is the name or symbol of God (Ishwara, Brahman). Om covers the whole threefold experience of man. It is the combination of three letters, namely, A, U, and M. “A” represents the physical plane. “U” represents the mental and astral plane, the world of intelligent spirits, and all heavens. “M” represents the whole deep-sleep state, which is unknown even in our wakeful state. This concept has been well described in various Indian scriptures. In Mandukya Upanishad, it has been described that Om is the syllable of the past, the present, and the future. From the original sound, Om, all things become manifest as its extension embodiments.
The analogy in Mundaka Upanishad describes that Om is the bow; the soul is the arrow; and Brahman is the target. The target is attained by an unerring man. One should become one with the target just like an arrow. This is to become one with the imperishable by eliminating the ideas of the body, ego, prana, hence being the self with nothing less than union with the absolute.
Svetasvatara Upanishad describes that Om is like the fire which though potentially present in firewood is not seen until two sticks are rubbed against each other. The self is like that fire; it is realized by constant awareness of the sacred syllable Om. Let the body be the stick that is rubbed and Om be the stick that is rubbed against. Then the real nature is realized which is hidden within, just as fire in a sense hidden in the wood.
Atharva Sikha Upanishad (Translation by Shri P. R. Ramachander)
Section - 2
2.1 The pranava (the sound of Om) makes all the souls to bow before it. It is the one and only one which has to be meditated upon as the four Vedas and the birth place of all devas. One who meditates like that goes away from all sorrows and fears and gets the power to protect all others who approach him. It is because of this meditation only that Lord Vishnu who is spread every where, wins over all others. It is because Lord Brahma controlled all his organs and meditated upon it, he attained the position of the creator. Even Lord Vishnu , parks his mind in the sound (Om) of the place of Paramathma (ultimate soul) and meditates upon Eeshana, who is most proper to be worshipped. All this is only proper in case of Eeshana.
2.2 Brahma, Vishnu, Rudra and Indra are creating all beings, all organs and all karanas. They are also capable of controlling them. But Lord Shiva exists in between them like sky and is permanently stable.
2.3 It is advised that the five gods Brahma, Vishnu, Rudra, Ishwara and Shiva should be worshipped in the form of pranava [Aa+Uu+Ma+sound+Bindu(full stop)].
2.4 Even if for one second, if one can stay and meditate on these, he gets more results than that of performing one hundred fire sacrifices. With the full understanding and knowledge, one should only meditate on paramashiva, which would give rise to all benefits. It is definite that, by sacrificing all other things, the twice born, should learn and understand this and he would get rid of the suffering of living in the womb and attain salvation.