Even we find A, U, M in Vedantic literature, which in Hinduism uses as “OM”.
The word AUM has been chosen because it is a short easily remembered syllable. The separate sounds of the word are symbols, nothing more. The combination of these three letter sounds in the one word symbolizes the world's unity.
The three divisions of time--past present and future--are also symbolized. Moreover AUM contains three letters and Atman contains three states. Finally just as it requires four quarters to merge and make up a whole unity, so A, U, and M are three of these quarters.
A: When one think of himself as seeing the waking experience ; but when he thinks of the self apart from that self is Atman.
U: he regards his -self as being in the dream. This is a higher idea, because he knows that the universe is an object to the subject which is Atman.
M: When one understands that through deep sleep he is able to measure all else, that all other things (and the sounds A and U symbolizing them) merge back into Deep sleep, are all found in it, and re-appear from it. This is a still higher degree.
Even if one takes any language he likes, he finds that A involves the opening of the mouth whereas M involves shutting it. Now all sound implies soundlessness, because it begins from that and ends with that. Hence the two always go together.
Similarly the knower and Known go together to form Brahman, are always present together although we do not usually recognize it. AUM= Turiya: This is not a state, as the ignorant Orthodoxy think.
This word includes all the three sounds, which have merged in it. So the waking merges in dream, the latter in sleep and all the three in AUM. The latter is a unity, nevertheless it contains a trinity. Thus when the word is made the subject of intelligent reflection, such meditation becomes a great help to attainment, as Advaitins says, for it thus becomes an examination of the whole of life.
Sounds imply names, names imply objects, objects imply whole world. "Au" is beginning of all sounds, "uM" is the end of all sounds, even other sound is included within them, i.e. within AUM.
Whatever may come in the future, whatever object existed in the past, whatever thing you can think of in the present--all these are included in the single word AUM, because all are named, hence are ideas, hence within the single mind.
The word is a mnemonic purposely invented to give men in one short syllable, in the smallest compass, a handy reminder that everything--this table, your neck-tie, that cow,--is of one and the same essential character. Every time any object is seen, you utter Aum and thus remember that it, and all other things, are the self. Every object in the external world is indicated by a name. Hence the phrase "the universe consists of names and forms.” All names are but words. As soon as a word is uttered, what does your mind do? A thought comes. Now all these words in every language, all these sounds, all these thoughts, are compressed in the one word Aum; which also enables all objects to be comprehended by the Mind as being ideas. Hence this word is unique. Nothing exists which is outside the scope of referential meaning AUM.
Aum therefore is the whole of existence, the universe. But why is this specific word Aum chosen for such high office? Take the first letter "AH". It is the sound phonetically uttered by the mouth when it first opens. "UM" is the sound it utters when at last it closes. Hence all sounds, without a single exception must be comprised between the opening and shutting of the lips, i.e. between "AH" and "UM" and as Brahman is silence, so ultimately the AUM disappears with the sounding of "UM" into silence, because the mouth must then shut. You have to use words to denote things, objects. You have to use letters to form words. The word AUM summarizes all other words. Finally even this word disappears when the sound of it goes. So the letting go of AUM is to make you drop the whole world and make you think of Brahman. Thus the mystery of AUM is wrapped in the meaning of words. Semantics aim at clarifying meanings but AUM ultimately shows you that all words are futile because they cannot express the ultimate nature of anything: Silence alone does this.
One cannot produce any sound without opening the mouth and the first sound he utters while opening the mouth is A. Thus A is said to pervade all sounds. A is considered to be the symbol of the universe because all objects are indicated by ideas, and all ideas are indicated by sounds and all sounds are pervaded by the letter A.
When we utter the word "sound" how can we understand the meaning of sound? It is only by distinguishing it from soundlessness that we can understand sound. All sounds are got from soundlessness. Similarly all the states are got from the Turiya, corresponding to soundlessness. We have to merge waking into dreams, then merge dream into deep sleep. And finally we have to merge even this into Turiya.
AUM is conceived as the whole universe, which has got four quarters. How can one know that the universe and the self-[soul] are identical? The answer is "Look into his -self--the Atman.” This Atman has also four corresponding quarters.
When one utter the word AUM, the waking comes before him: when he thinks of dream, the dream states come before him; and so also with sleep. Thus every time he utters the word AUM the three states come before him.
Meditation on symbols is meant for dull and mediocre intellects. When we utter the word AUM we must think of the three states and also of the Ataman.
Aum is a sound, how can it be an elephant? "All sounds" means all objects, or entire Brahman.
Anything which is a thought, is an idea, and hence a superimposition. Aum is the substratum of all the words. It is the word of Atman. Aum stands for the sound and not the letter which is found in all languages. It sums up all the sounds in all the languages. As upon the mind everything else is super-imposed, so upon the Aum everything else is superimposed.
The sound has for its substratum or substance one’s own self. It comes from and disappears into the self, which is Atman.
All this baggage is not necessary in pursuit of truth. Seeker has to find and realize “What is mind?” and “What is the substance of the Mind?” nothing else in order to unfold the mystery of the physical existence [universe]. The individual experiences happening within the universe, such as birth, life and death and pain and pleasure are nothing to do with the self, which is formless consciousness. Thus, it is necessary to know the self is formless to realize the fact that, the burden of the human is not on the body but it is on the Self [soul or consciousness], which the religionists call it as God or Brahman or Christ or Buddha and intellectuals call it as Consciousness.
Thus consciousness alone is real. The human and universe is mere mirage created out of consciousness. Know the consciousness as true self then one becomes free from experiencing the mirage (experience of the birth, life, death and the world )as reality.
