Mandukya Upanishad – 12 Verses on AUM

Pure Consciousness seems to play as waves of beauty, so does Atman appear to play as if it has four aspects; Waking, Dreaming, Deep Sleep and Turiya (this means “the fourth”). This Upanishad, that is all about AUM, only counts 12 verses. It shows us the four apparent states, level, or planes of Consciousness in which the Atman seems to play; Vaishvanara (or Visva), Taijasa, Prajna and Turiya in relation to AUM mantra. It presents all the channels and instruments through which manifestation (maya) seems to exist and through which Atman seems to experience the apparent manifestation.
 
By contemplating and witnessing these levels, channels and instruments (see also Yogic Self-awareness Assessment) they are seen as parts of the not-self, leading the student to the real Self, to Atman. Eventually the understanding comes that Atman and Brahman are one and the same, which is also called Yoga. If one would be able to fully grasp what is offered in this Upanishad, one needs to know no more, because Self-realization would have been attained. In the Yoga Sutras AUM has been offered as a direct route, thus this Upanishad, that is all about AUM, is the direct route for Self-realization.

From the Karika, a commentary on the Mandukya by Gaudapada.
Verse 22-25: He who knows for certain the similarity of the three states and the three letters of AUM, based upon their common features, is worshipped and adored by all beings and also is a great sage. Through meditation on A the seeker attains Visva; through meditation on U, Taijasa; and through meditation on M, Prajna. Meditation on the “soundless” brings no attainment. 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.

Swami Rama 8 lectures on Mankukya Upanishad:

MANDUKYA UPANISHAD

1: Hari Om. Om-ity-etad-aksharam-idam sarvam, tasyopavyakhyanam bhutam bhavad bhavishyaditi sarvam-omkara eva. Yaccanyat trikalatitam tadapy omkara eva
 
All is OM: Hari Om. The whole universe is the syllable Om. Following is the exposition of Om. Everything that was, is, or will be is, in truth Om. All else which transcends time, space, and causation is also Om.
 
2: Sarvam hyetad brahmayam-atma brahma soyamatma catushpat
 
Atman has Four Aspects: All of this, everywhere, is in truth Brahman, the Absolute Reality. This very Self itself, Atman, is also Brahman, the Absolute Reality. This Atman or Self has four aspects through which it operates.
 
3: Jagarita-sthano bahish-prajnahsaptanga ekonavimsatimukhah sthula-bhug vaisvanarah prathamah padah
 
First is Waking / Gross: The first aspect of Atman is the Self in the Waking state, Vaishvanara. In this first state, consciousness is turned outward to the external world. Through its seven instruments* and nineteen channels* it experiences the gross objects of the phenomenal world.
 
*The seven instruments are the more macrocosmic instruments, while the nineteen channels relate more to the microcosmic, individual person.
 
Seven Instruments: First, Consciousness manifests outward as elements space, air, fire, water, and earth, along with the individuation from the whole and the flow of energy (which we know as the pulsing impulse towards breath).
 
Nineteen Channels: Then, the individual operates through the four functions of mind (aspects of antahkarana, the inner instrument), which are manas, chitta, ahamkara, and buddhi. Those four operate through the five vayus (prana, apana, samana, udana, and vyana), the five active senses or indriyas (karmendriyas of eliminating, procreating, moving, grasping, and speaking), and the five cognitive senses (jnanendriyas of smelling, tasting, seeing, touching, and hearing)
 
4: Svapna-sthano’ntah-prajnah saptanga ekonavimsatimukhah praviviktabhuk taijaso dvitiyah padah
 
Second is Dreaming / Subtle: The second aspect of Atman is the Self in the Dreaming state, Taijasa. In this second state, consciousness is turned towards the inner world. It also operates through seven instruments and nineteen channels, which engage the subtle objects of the mental realm.
 
5: Yatra supto na kancana kamam kamayate na kancana svapnam pasyati tat sushuptam. Sushupta-asthāna ekibhutah prajnanaghana evanandamayo hyanandabhuk chetomukhah prajnastrityah padah
 
Third is Deep Sleep / Causal: The third aspect of Atman is the Self operating in the Deep Sleep state, Prajna. In this third state, there is neither the desire for any gross or subtle object, nor any dream sequences. In deep sleep, all such experiences have receded or merged into the ground of undifferentiated consciousness. Here, one is filled with the experience of bliss, and can also find the way to clearer knowledge of the two preceding states.
 
6: Esha sarvesvara esha sarvajna esho’ntaryamy-esha yonih sarvasya prabhavapyayau hi bhutanam
 
Find the Experiencer: The one who experiences all of these states of consciousness is the omniscient, indwelling source and director of all. This one is the womb out of which all of the other emerges. All things originate from and dissolve back into this source.
 
7: Nantah-prajnam na bahih-prajnam, nobhayatah-prajnam na prajnana-ghanam na prajnam naprajnam. Adrishtam-avyavaharayam-agrahyam- alakshanam-acintyam-avyapadesyam-ekatma-pratyayasaram, prapancopasarnam santam sivam-advaitam caturtham manyante sa tm sa vijneyah
 
The Fourth Aspect is Turiya: The fourth aspect of Atman or Self is Turiya, literally the fourth. In this fourth state, consciousness is neither turned outward nor inward. Nor is it both outward and inward; it is beyond both cognition and the absence of cognition. This fourth state of Turiya cannot be experienced through the senses or known by comparison, deductive reasoning or inference; it is indescribable, incomprehensible, and unthinkable with the mind. This is Pure Consciousness itself. This is the real Self. It is within the cessation of all phenomena. It is serene, tranquil, filled with bliss, and is one without second. This is the real or true Self that is to be realized.
 
8: So’yam-atma adhyaksharam-omkaro dhimatram pada matra matrasca pada akara ukaro makara iti
 
Those Four are the Same with “A-U-M” and Silence: That Om, though described as having four states, is indivisible; it is pure Consciousness itself. That Consciousness is Om. The three sounds A-U-M (ah, ou, mm) and the three letters A, U, M are identical with the three states of waking, dreaming, and sleeping, and these three states are identical with the three sounds and letters. The fourth state, Turiya is to be realized only in the silence behind or beyond the other three.
 
9: Jagarita-sthano vaisvanaro’karah prathama matra. apteradimatvad-vapnoti ha vai sarvan kamanadisca bhavati ya evam veda
 
The Sound “A” is Waking / Gross: Vaishvanara is the consciousness experienced during the waking state, and is A, the first letter of Om. That simple sound of A is first and permeates all other sounds. One who is aware of this first level of reality has fulfillment of all longings and is successful.
 
10: Svapna-stahnas taijasa ukaro dvitiya matrotkarshadu-ubhayatvad- votkarsati ha vai jnana-santatim samanasca bhavati nasyabrahmavit kule bhavati ya evam veda
 
The Sound “U” is Dreaming / Subtle: Taijasa is the consciousness experienced during the dreaming state, and is U, the second letter of Om. This intermediate state operates between the waking and sleeping states, reflecting some qualities of the other two. One who knows this subtler state is superior to others. For one who knows this, knowers of Brahman, the Absolute Reality, will be born into his family.
 
11: Sushupta-sthnah prajno makras tritiya mtr miterapiter va minoti ha va idam sarvam-apitisca bhavati ya evam veda
 
The Sound “M” is Deep Sleep / Causal: Prajna is the consciousness experienced during the state of dreamless, deep sleep, and is M, the third letter of Om. It contains the other two, and is that from which the other two emerge, and into they recede or merge. A knower of this more subtle state can understand all within himself.
 
12: Amatras-caturtho’vyavaharyah prapancopasamah sivo’dvaita evamomkara atmaiva samvisaty-atman-atmanam ya evam veda.
 
Silence after “A-U-M” is the True Self: The fourth aspect is the soundless aspect of Om. It is not utterable and is not comprehended through the senses or by the mind. With the cessation of all phenomena, even of bliss, this soundless aspect becomes known. It is a state of nondual (advaita) reality—one without a second. This fourth state, Turiya, is the real Self or true Self. One with direct experience of this expands to Universal Consciousness.

This animation might inspire a deeper and broader understanding of the wisdom and realization that the Mandukya Upanishad contains.