Mandukya Upanishad
aum ity etad akṣaram idam sarvam, tasyopavyākhyānam
bhūtam bhavad bhaviṣyad iti sarvam auṁkāra eva
yac cānyat trikālātītaṁ tad apy auṁkāra evaAll is OM: Hari Om. The whole universe is the syllable Om. Everything that was, is, or will be, verily is Om. All that which transcends time, space, and causation is also Om.
sarvaṁ hy etad brahma, ayam ātmā brahma
so’yam ātmā catuṣ-pātAll this, everywhere, in truth, is Brahman. This Atman itself, is also Brahman, the Absolute Reality. This Atman or Self has four aspects through which it operates.
jāgarita sthāno bahiṣ-prajñaḥ saptāṅga
ekonaviṁśati-mukhaḥ sthūla-bhug vaiśvānaraḥ
prathamaḥ pādahThe first aspect of Atman is the Self in the Waking state, Vaishvanara. Its consciousness is outward-turned. Through its seven instruments and nineteen channels[1] it experiences the gross objects of the phenomenal world.
svapna-sthāno’ntaḥ-prajñaḥ saptāṅga ekonavimśati-mukhaḥ
pravivikta-bhuk taijaso dvītiyaḥ pādahSecond is taijasa, Atman in the Dreaming state. In this 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.
yatra supto na kaṁ cana kāmaṁ kāmayate
na kaṁ cana svapnam paśyati tat suṣuptam
suṣupta-sthāna ekī-bhūtaḥ prajñānā-ghana evānanda-mayo
hy ānanda-bhuk ceto-mukhaḥ prājñas tṛtīyaḥ pādahThird is Prajna in which the Atman is the Self operating in the Deep Sleep state, Prajna. In deep sleep, one becomes undivided, an undifferentiated mass of consciousness, consisting of bliss and feeding on bliss.
eṣa sarveśvaraḥ eṣa sarvajñaḥ, eṣo’ntāryami,
eṣa yoniḥ sarvasya prabhavāpyayau hi bhūtānāmFind 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.
nāntaḥ-prajñam, na bahiṣ prajñam, nobhayataḥ-prajñam
na prajnañā-ghanam, na prajñam, nāprajñam;
adṛṣtam, avyavahārayam, agrāhyam, alakṣaṇam,
acintyam, avyapadeśyam, ekātma-pratyaya-sāram,
prapañcopaśamam, śāntam, śivam, advaitam,
caturtham manyante, sa ātmā, sa vijñeyaḥThe Fourth Aspect is Turiya, In this consciousness is neither turned outward nor inward. Nor is it both outward and inward; it is neither knowing nor knowing. This cannot be experienced through the senses; it is indescribable, incomprehensible, and indefinable, its sole essence being the consciousness of its own Self. This is Pure Consciousness itself. This is the real Self, the coming to rest of all relative existence; It is iutterly quiet, serene, tranquil, filled with bliss, and is one without second. This is the real or true Self that is to be realized.
so’yam ātmādhyakṣaram auṁkaro’dhimātram pādā mātrā
mātrāś ca pādā akāra ukāra makāra itiThose Four are identical 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.
jāgarita-sthāno vaiśvānaro’kāraḥ prathamā
mātrā’pter ādimattvād vā’pnoti ha vai
sarvān kāmān ādiś ca bhavati ya evaṁ vedaVaiśvānara, whose field is the waking state, is the first sound, A, of Om. That sound of A is first and permeates all other sounds. One who who knows thus, encompasses all desirable objects; and becomes the first, ie successful.
svapna-sthānas taijasa ukāro dvitīyā
mātrotkarṣāt ubhayatvādvotkarṣati ha vai
jñāna-saṁtatiṁ samānaś ca bhavati
nāsyābrahma-vit-kule bhavati ya evam vedaTaijasa, whose field is the dream state, is the second sound, U. This intermediate state contains the qualities of the waking and sleeping states. For One who knows thus, knowers of Brahman, the Absolute Reality, will be born into his family.
suṣupta-sthānaḥ prājño makāras tṛtīya mātrā
miter apīter vā minoti ha vā idaṁ
sarvam apītiś ca bhavati ya evaṁ vedaPrājña, whose field is deep sleep, is the third sound, M, because this is the measure, and that into which all enters. He who knows thus, measures all and becomes all.
amātraś caturtho’vyavahāryaḥ prapañcopaśamaḥ sivo’dvaita
evam auṁkāra ātmaiva, saṁviśaty ātmanā’tmānaṁ ya evaṁ
veda ya evaṁ veda
The fourth, Turiya, is soundless: unutterable, the cessation of all phenomena, even of bliss. It is nondual (advaita) reality — one without a second. Thus Om is the ātman, is the real or true Self. One who knows thus, merges the self in the Universal Consciousness.
Om śantih; śantih; śantih
[1] 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 antahkaranas, 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)