The letters A,U, and M created the friction that led to the beginning: the creation, preservation, and the dissolution. These three are known mythologically as the Conch of Visnu, The Damaru of Shiva, and the Tongue of Brahma. The primary manifestation of all activity is the cosmos comes from the principle of the three sounds.
The meaning of OM
What is the meaning of OM in the context of the Upanishads? The Upanishads teach that there is an eternal consciousness which remains ever the same is characterised by the functioning of the external senses, which receive and respond to the stream of impressions. The waking state appears to be the dominant state for the working of human life.
But each day, this waking state comes to a complete end when we withdraw into ourselves, close the doors and windows of the senses, and let our minds drift into an altogether different realm: the realm of sleep with dreams. Here again there is experience which seems similar to that of the waking state, but our environments in dream, the feel of our bodies, the people we mix with, are often very different to the scenario of our waking life. In dream, we can mingle happily with long lost relatives, somehow the pains of the body in the waking state have disappeared, and laws of time, space and causation, seem curiously flexible. The main thing about the dreaming state is that the outer senses are not operative; the whole spectacle takes place internally.
Then there is a third state, the state of dreamless sleep. This is a condition where dreams come to an end and there is total absence of mental activity. How do we know? We know in retrospect, when we wake up and feel: ‘Ah I must have slept so well, I remember nothing at all.’
The Upanishads say that dreamless sleep is a state of bliss, but such bliss is of a negative nature. It is the bliss of complete absence of the pairs of opposites, limitations and finitude. It is a kind of release and close to liberation, except that it is not a conscious experience. No one becomes liberated by going to sleep each night. This state too is brought to an end by our return to the waking state.
These three states make up the totality of empirical experience. It is clear that these states are passing and cancel each other out. Therefore, in the Vedanta analysis, they do not deserve to be called absolutely real. The vast importance of the waking state comes to a humble and humiliating end when we drift into dream. The fantastic imaginings of dream are more patently unreal, and they are completely dissolved when we wake up, or when we sink into dreamless sleep. And dreamless sleep, however sweet a condition, is rudely broken when we awaken from it and have to take on all the duties and burdens of waking life once again.
But all the time, alongside these three states, and illumining them from within, is the eternal consciousness, our true Self. It is sometimes called the fourth, or turiya; though far from being one more state like the others, turiya is the witness and support of all the three states. When understood, turiya is realised to be the whole of experience, the Absolute. Without this turiya, this eternal consciousness, the whole phenomenal cycle of waking, dream and dreamless sleep would have nothing to rest on. This eternal consciousness is not broken or interrupted by anything. It is this consciousness, which, reflected in the mind, gives us the senses of continuous identity, of being the same self, in spite of apparently losing ourselves completely in sleep and dream.
This is the Self to be realised, to be uncovered, in order to be liberated from the realm of the perishable. It is here that the symbology of OM shows us a path to freedom. OM points to the whole of the phenomenal realm, in its three phases, and also to the transcendent, which is the light behind experience. This way of analysing our experience can be shown by the visual symbol of OM, with the curves – lower,
middle and upper – representing, respectively, the states of waking, dreaming and dreamless sleep. Above these curves there is another which is set apart from the main form, to denote transcendence with the point signifying infinity.
Throughout experience, whether external, internal or quiescent as in deep sleep, the divine is always present equally as the turiya, just a the higher curve and the point always accompany and dominate the lower three. Therefore OM is a visual symbol representing the whole of experience both relative and absolute, finite and infinite.
The Mandukya Upanishad also shows how the word OM is a great symbol. The three states are represented by parts of the sound OM itself. Here the sound OM is depicted as having three phases. They are usually represented in English by the letters A, U and M. The sound A (pronounced as in path) is the characteristic sound of the waking state. It is the sound of life and response to outer stimuli. A is the first sound produced when opening the mouth. The middle sound, U (pronounced as the oo in soon), is attributed to the dreaming state, and to states of internal mental activity, where we are withdrawn from outer objects. Mmm represents the Divine, and is associated with Lord Ganesha.
source: from the writings of Swami Rama