"AUM is only a formula, just like H20. It simply represents the whole reality. Before we enter into this, the greatest formula invented ever by man, you have to understand a few things. First: AUM is not written in Sanskrit in the ordinary Sanskrit alphabet; it has a special symbol for itself. It is a code word. To make it clear, the ordinary Sanskrit is not used for it — a SPECIAL symbol, hence it is untranslatable.

It consists of three sounds AND the fourth, the soundless sound. It consists of four things: three are sounds and the fourth is only the harmony of those three sounds. Three sounds are AUDIBLY there, you can hear them. The fourth is heard not by the ears; it is heard only at the innermost shrine of your being.

So the symbol AUM consists of four things. Three are the basic sounds: aa-oo-ma — A, U, M. These are the basic sounds; all other sounds are branches of these three sounds. This is the real trinity, the trinity of sounds. All these three have arisen out of the fourth, but the fourth is inaudible, unhearable.

The fourth is represented only by a dot; that dot is called ANUSWAR.

If you go into an empty temple or a mosque or a church, or any empty house will do — a newly built house, utterly empty... go inside and start chanting the mantra AUM. "AUM, AUM, AUM.... " You go on chanting, then stop suddenly. Now you are no more chanting, but the vibe is still there, a humming sound... disappearing, disappearing... every moment disappearing, becoming more and more subtle... the humming sound, the tail-end of M. When you say "AUMMMMM..." that tail-end of M will be heard when you have stopped chanting.

That is represented only by a dot; in Sanskrit that dot is called ANUSWAR. Out of that dot arise three sounds A-U-M. These four represent the whole existence, these four are the four dimensions of existence. [...]

The three, the first three, represent your three states, and the fourth, your self-nature. Man is also exactly as AUM; man is a miniature universe. If we can decipher man we will be able to decipher the whole of existence. If we can know a single dewdrop in its totality we will have known all the oceans, because we will have dissected a single drop which contains the secret of all the oceans. We will come to know the formula H20, and that's the secret. [...]

You are a dewdrop of God, of the whole, of this organic infinity, of this eternity. The best way to understand the universe, the truth, the existence, is to understand yourself. Socrates is right when he says, "Know thyself," because, knowing that, you will be able to know all. [...]

This first sound, A, represents your so-called waking state. Remember the word 'SO-CALLED' — underline it in red. It is so-called waking, because a really awakened person becomes bigger than the whole. He becomes a Buddha, a Christ, a Krishna. Our waking is only so-called, only a very small fragment of our being becomes conscious.

When in the morning you wake up it is not much of a waking. You just open your eyes, you become capable of doing the most superficial things. You can prepare your breakfast and serve tea to your wife and make your children ready to go to school — and all these things are done in a very mechanical way. You are not really conscious of what you are doing because you have been doing it for many many days, for many many years, for many many lives; you can function like a robot. [...]

But this is how the whole of humanity is. People are living, dying, not knowing why they live, not knowing why they die. People are struggling to survive not knowing for what. People are rushing with great speed, not knowing where. They are not even aware of who they are — what kind of awareness is this?

Hence, call it so-called wakefulness. [...]

Experience of the inner world corresponds to U, the second sound. [...]

The second is the state of dreaming. The first is the so-called waking state, the second is the dreaming state — it is introversion. The first creates science, the second creates art. The first is an objective approach towards reality, the second is a subjective approach towards reality. The poet, the painter, the singer, the dancer, the musician, they all belong to the second: the introverted state. [...]

The state of dreamless sleep corresponds to M, the third sound. [...]

The third is a negative state of transcendence, JAD SAMADHI; it is not true SAMADHI, but very close. The man has fallen into a deep unconsciousness, but he is silent; there is no turmoil within.

But it is a negative state; there is no light, there is only darkness. Even dreams have gone. There has happened a certain merging. He has tasted THE MEASURE OF ALL THINGS, but in a deep unconscious state. [...] 

But this is not true SAMADHI. We call it JAD SAMADHI — unconscious SAMADHI — but it has come very close. This is the closest to the fourth, TURIYA. [...]

The third has only tasted of God, the fourth has become God himself. He can say, "AHAM BRAHMASMI — I am the Supreme, I am the Absolute!" He can say, "ANA'L HAQ!" like Mansoor al- Hillaj — "I am the truth." Only then... but this can be said only when your unconsciousness becomes luminous, when the darkness of the third disappears, when its negativity disappears and it becomes a positive experience in full awareness. We call this state Buddhahood. and reaching the fourth, TURIYA, the part becomes bigger than the whole. The miracle has happened. The miracle is so immense that it cannot be described — words fall short." 

— OSHO, Philosophia Ultima, Chapter #13 - Fri, 23 December 1980 am in Buddha Hall 

With gratitude and thanks to Swami Neelamber

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