Upanishad Vahini
Taithiriya Upanishad

Knowledge of Brahman (Brahma-vidya) is the specific theme of this Upanishad. It has three chapters on:
instruction (Siksha-valli), bliss (ananda-valli) or Brahman (Brahma-valli), and Bhrigu (Bhrigu-valli). In the Chapter on instruction, certain methods are detailed to overcome obstacles placed in people’s way by gods and sages (devas and rishis) and to acquire one-pointedness in mental exertions. This chapter has twelve sections.
The last two chapters are very important for those seeking knowledge of Brahman (Brahma-jnana). Both chapters give instruction on the knowledge of the sage Bhrigu (Varuni Vidya), which leads to liberation, so they are practically the same. For convenience of study, it is dealt with in two sections, that is all.
The objective world is caused by ignorance, with bondage the result
In the Siksha-valli, subjects are dealt with that are not antagonistic to action (karma), like the combination of letters according to euphenic rules (samhitha), and also subjects that are associated with dedicated action, like worship (upasana). These lead to self-rule (swa-rajya). But the complete destruction of worldly flux (samsara) will not be accomplished by just these. Worship exists along with desire, so, like activity, even worship cannot bring about liberation.
All this flux, this objective world (samsara), is due to ignorance (a-jnana), and bondage is the result. So, when ignorance is destroyed, the bonds loosen and liberation is attained. Ignorance is there, persisting, through natural causes. It is just like the delusion that your train is moving when actually your train is stationary and the train on adjacent rails is moving! Watch only your train, and you know the truth; watch the other train, and you are deceived. There is no use seeking to know the cause of this delusion. Seek how to escape from it. This ignorance, which is the seed out of which the flux sprouts, can be destroyed only by knowledge of Brahman (Brahma-jnana).
There is no other method.
Liberation cannot be produced by any action
All that is caused, everything that is a result, is short-lived; this is evident from the scriptures (sastras) as well as from experience and reason. The scriptures speak of aspirants who discarded even higher regions like Heaven, which are attainable by persons who perform the prescribed rites, for liberation is beyond the reach of those who dwell therein. Heaven and Hell are results of actions, they are objects made, so they cannot be eternal; they are conditioned by birth, growth, decay, and death. They do not exist from the very beginning; they were made; before that act, they were not. That which once was not and later will not be is as good as “not” even in the present. The fruit of action (karma) shares this quality, so it cannot grant eternal joy.
No effort can result in the creation of space (akasa) now; what already exists cannot be produced anew. Liberation (moksha) exists and is there self-evident. It cannot be produced anew by any action (karma). The moment the ignorance (a-jnana) that hides it from experience disappears, you are liberated and know your Reality; you are free from bondage. Prior to that moment, you were free, but you imagined you were bound and you behaved as if you were bound. How then are you to get rid of this idea that you are bound? By listening to the teachings of the Vedas with faith therein. Only then can ignorance perish. The chapter on Brahman in this Upanishad has the task of presenting these teachings.
It is in the nature of things that ignorance prompts people to crave plentiful fruits through the performance of actions. Then, they become despondent, and the cravings only bind them more and don’t help to make them free.
The craving for fruit is hard to shove off, though this fearful flux of growth and decay makes them shiver in dread.
Brahman is Truth, Omniscience, Eternal
In this Upanishad, the three words truth (sathya), spiritual wisdom (jnana), and eternal (an-antha) are meaningfully affixed to Brahman, to explain Its characteristics. These are three distinct words, signifying qualities, seeking to mark out the One from the rest, the One Brahman from other types of Brahman that don’t have these traits. That is to say, Brahman is not to be confused with anything that is not truth, spiritual wisdom, and eternal.
Everything that is limited by time, space, and objectivity is inert (jada) material and apparently different from Brahman. The characteristics of truth, spiritual wisdom, and eternity help to differentiate and distinguish the real Brahman from kindred and similar phenomena. Whichever form a thing is determined to have, if that form is unchanged, then it is referred to as truth. If that form undergoes change, then it is falsehood. Modification is the sign of untruth; absence of modification is the sign of truth.
Brahman is truth (sathya), that is to say, It has no modifications. It is eternal (nithya), unaffected by time.
All that is not Brahman - that is, the world (jagath) - is subject to change. All objects are subject to the triple process of the intellect (buddhi): known, the knower, and knowledge. Hence, the intellect is spoken of as a cave (guha) where the three-fold process resides.
Do not swerve from Truth, duty, well-being of all
In the Thaithiriya Brahmana, as well as this Upanishad, dharma is also treated elaborately. It has three forms: desirable (kamya), produced by a cause (na-imitthika), and eternal (nithya). The scriptures (sastras) seldom command that action (karma) be pursued; there is no need to do so, for action comes naturally to people.
Desire (kama) is the prompter of such action, and people get various fruits thereby. The scriptures teach only the ways of directing this natural activity to ensure desirable objects.
The Upanishad exhorts you not to swerve from duties of learning and teaching, saying,
Swerve not from the true and the truth. ... From the true, it will not do to swerve,
nor from dharma, nor from welfare and well-being, nor from duties to gods and fathers.
Treat thy mother as God. Works that are free from fault should be re-sorted to, not others ....
The science of spirituality is the highest field of experiential knowledge
Listening, rumination, and concentration are the three steps in realisation. Listening refers to the Vedas, which have to be revered in faith and learned by heart from a spiritual teacher (guru); this confers the knowledge of the Unknowable. Rumination (manana) is the austerity (tapas) taught in the chapter on Bhrigu. By this process, the essence of Brahman can be fixed in the mind. Concentration helps the development of single-minded attention on the principle so installed. The two chapters on Brahma and Bhrigu expound on the discipline that ensures the realisation of Brahman (Brahma-vidya). The chapter on Brahman teaches; the chapter by Bhrigu proves by experience.
Bhrigu, Varuna’s son, tells him that Brahman is food (anna), life-breath (prana), the senses, the mind (manas), speech (vak), etc. But, since the son soon learns that these are not Brahman, he declares that Brahman is that from which these are born and by which they live and function. He first believed that food is Brahman, since all beings exist on food, but, later, he feels that Brahman is much more inclusive. He asks for direct teaching of the Real, the Brahman.
Thereafter, he is told that austerity (tapas) is Brahman, for it is that by which Brahman the Reality is known.
He discovers by austerity that the highest wisdom (vijnana) is Brahman, for wisdom is that in which creatures are born and it is that by which creatures live.
Thus, it is announced that of all disciplines and subjects of study, the realisation of Brahman (Brahma-vidya) is the most sacred, holy, and esoteric.
Contemplate on the five sheaths of the human
Food (anna) is not to be decried; that should be the vow of the wise. The vital airs (prana) are all food. The physical body is the gift of food, and the vital airs have the body as the vehicle. So, food should not be slighted.
That should be the resolution.
The waters, in conjunction with the fire in the stomach, become food. In the water that comes down as rain, the “fire” of lightning is inherent. So, whoever is established in the splendour of water is aware of the splendour of food and is persuaded to revere it. Food is the guru, for it leads you on to the knowledge of Brahman. Therefore, it should not be treated with disrespect. That must be observed just like a vow by the aspirant.
Since the physical body is the transformation of food, it has a food sheath (anna-maya kosa). The vital airs form the vital-air sheath (prana-maya kosa). Weighing between good and bad, right and wrong is the function of the mind sheath (manomaya kosa). Fixing upon a step, with a purpose in view, is the function of the sheath of intuition or spiritual wisdom (vijnana-maya kosa). Finally, the joy of achievement is tasted by the sheath of bliss (ananda-maya kosa).
Rise from the gross to the subtle stage by contemplating on the vital breath
The vital-air sheath is the first instrument in order to progress with the Brahmic outlook - that you are Brahman and not the body, etc. It is subtle, separate, and different from the body. It is activated by and saturated with the God of Wind (Vayu). It pervades and subsumes the entire food sheath.
You can say that the vital-air sheath is the soul of the food sheath, for it makes it function from head to foot.
It cannot survive without the vital air (prana). It is the motive force; it has five varieties: breath, downward breath, diffused breath, rising breath, and digestive air (prana, apana, vyana, udana, and samana). By contemplating that the vital-air sheath is the Atma of the food sheath, the notion that the body is the Self will disappear. You rise from the gross to the subtle. Breath (prana) is like the molten metal in the crucible. By effort, the vital-air sheath can be experienced.
The vital air appears in the form of the breath. The vital air activates the head, diffused breath the right part of the body, rising breath the left, digestive air the central, and downward breath the lower part of the body. The vital air moves from the heart through the nerves to the face, nose, etc., and reaches the head. From there, it motivates the various nerves flowing through the body under different names, with distinct names and distinct functions.
The vital air that functions around the navel is, for example, called the digestive air.
Mantras illumine the Atmic splendour
For the mind sheath, the Yajur-veda is the head. The hymns form the right wing; chanting the left wing.
Brahmanas are the soul and the Atharvana-veda is the tail. The mantras of the Yajur-veda are used very much in sacrifices; with them, food is offered ceremonially in the sacrificial fire. Hence, it is considered as the head. The sound of sacrificial prayer (yajus) produces auspicious modification. That is also the reason for the significance attached to the other Vedas. Thus, all mantras become the causes of mental modifications. These in turn illumine the splendour of the Atma. So, the Vedas and the mystery of their syllables belong to the science of the Atma itself.
The Vedas become eternally valuable and eternally existent. The Atharvana-veda treats various rites to win relief from evil forces and ailments, so it is described as the tail.
The mind sheath merges in the sheath of intuition and later into the bliss sheath; finally, the aspirant passes beyond even that, into the region of pure being (sat).
Selected Excerpts From This Discourse