The Upanishad speaks of the cave in which the Atman is hidden, as it were. This cave is nothing but the series of the five kosas or sheaths, namely, (1) Annamaya, (2) Pranamaya, (3) Manomaya, (4) Vijnanamaya, and (5) Anandamaya Kosas, the succeeding one being internal to the preceding. The physical body is the Annamaya-Kosa, which is born out of the essence of the food consumed by the parents, and it is again sustained by the essence of the food given to it. This body has a beginning and an end, and so does not have the character of eternity found in the Atman. It is unconscious, changeful and external, and hence different from the Atman which is Consciousness, unchanging and universal. If it is supposed that the body is Atman, it would follow that it should come into being without there being a reasonable cause, because as an effect, the body ought to have a cause and the cause should necessarily exist prior to the effect. If the determining cause of the body should rise simultaneously with the body, then, the body would be undergoing experiences which it really does not deserve, there being no logical connection between the cause and the effect. Anyone would be experiencing anything without any rationality behind it. That the body of a particular individual has particular experiences shows that it has a determining cause, and this cause being connected with it inseparably, it is clear that the experiencer in the present life ought to have existed in the previous life also; and as the body could not have existed prior to this birth, the doer of the actions causing present experiences must be someone other than this body and yet connected with this body. If this logical factor is denied, there would be the defect of what is called Akritabhyagama or the coming in of what is not deserved by oneself. Similarly on the death of the body there would be Kritanasa or the destruction of the merits of all actions without their being enjoyed. Thus there would be chaos in the universe and no law determining anything. For all these reasons we should conclude that the body is not the Atman.

The Prana is internal to the body, subtler and more pervasive, propels the senses, and gives power to the body. But it cannot be the Atman since it is an effect of Prakriti, changing in nature and also unconscious. It is also characterised by externality. The mind or the Manas has the sense of ‘I-ness’ in regard to the body and ‘mine-ness’ in regard to its possessions, such as house, etc. It is affected by the course of life, by desire, passion, anger and the like and on many occasions gets confused and cannot know the true nature of anything. It gets dissolved in swoon, sleep, etc., and it is also a mode of Prakriti. It is thus not the Atman. The intellect is internal to the mind, more subtle and pervasive, but gets dissolved in sleep and other unconscious states. It pervades the body in waking, from head to foot, in association with the Chidabhasa or the reflection of the Atman in the Sattvika-Prakriti. It has a beginning and an end. It is an effect and is unconscious without the reflection of the Atman in it. The intellect and the mind act as the agent of action and medium of action, respectively, the intellect going by the name of Karta, or doer, and the mind Karana, or instrument. As the doer and the process of doing, the two are distinguished, and hence, though included in the single principle of the Antahkarana, they become causes of two different sheaths called Manomaya and Vijnanamaya. The intellect is not the Atman for similar reasons as the mind.

The Atman reflected in the Sattvika Buddhi is called Chidabhasa. The Buddhi, by itself, is unconscious because of being an effect of Prakriti, but it assumes intelligence when the Atman is reflected in it. This itself is the Jiva. The Ahamkara or the principle of ego is associated with it, so that the ego and the intellect go together.

When they are in an inactive state, there is a passive introversion of their modes which goes by the name of sleep. The Vrittis of the mind, being accustomed to contact with external objects and unfamiliar with any supernormal experience, find nothing positive when there is a forced introversion brought about either by fatigue or by frustration, but there is some sort of a joyous experience when the Anandamaya-kosa or the causal body is in operation on account of its being the medium of the fructification of the meritorious actions which one has performed in previous lives. All happiness that the Jiva has in this world is nothing but a logical consequence of the good things it has done in its past lives. When there is a cessation of conscious experience, there is sleep. This causal body, too, is not the Atman, because it has a beginning and an end, for it is the cumulative effect of the actions of the past and shall cease to be when there dawns spiritual knowledge and realisation. The causal condition cannot be identified with eternal and infinite Being, as the cause is connected with an effect which is obviously other than itself. It cannot have the character of universality. The Atman is that which is the very presupposition of all thinking and experience and so no Jiva has an experience of it for the reason that in the universal Atman there is no distinction between the knower and the known. It is experience itself, and not any objective experience. It cannot be known by another process of knowing different from itself. It appears to be non-existent from the point of view of the Jivas, because the latter have no means of perception of what is universal, they being used to sensory and mental perception alone.

They are three types of the unknowable: (1) That which is absolutely non-existent and therefore cannot be known, such as the horns of a hare; (2) that which does not have any contact with the operative Vrittis of the mind for the time being, such as distant objects and unthinkable regions such as heaven; (3) Universal Being in which there is no possibility of the operation of the Vrittis. The latter function only where there is the idea of space, time and cause; not in Brahman, the Absolute, which is prior to all these. The Atman is the Light of all lights. It precedes even the light of thinking and understanding. It is Svayamjyoti, or Self-luminous. Everything shines after it, and everything borrows light from that absolute light. It being the Knower, it cannot be known. This is a clue to the understanding of the nature of ignorance in which the Jivas are shrouded, and also a hint for the Jivas to find their way to rising above their predicament of Jivahood and Samsara.

Anandamayakosa is a name given to the latent condition of the Vrittis of the Antahkarana, wherein not only the manifested but also all the unmanifested potencies of future possible experiences are hidden. They are the subtlest impressions of all past thoughts and deeds, ready to germinate when proper conditions are provided. The providing of such conditions is called birth. (Verses 1-10)

There is nothing that one can know, other than the sheaths, and the sheaths are not the reality. But the fact of there being an experiencer of the states of sheaths, which are all relative, cannot be denied. This is the Atman. The self-luminous Atman, being the knower of all things, cannot be known by anything else. The Upanishad says: ‘Who can know Him by whom everything else is known? Who can know the knower?’ The mind, which is the means of knowing, is not to make the Atman its object, because in the Atman the opposition between the seer and the seen is abolished. The mind can know only what is knowable as an external object, but it cannot know what cannot be objectified, and the Atman is unknowable as pure experience free from the opposition of the knower and the known. Its unknowability therefore does not indicate its non-existence. Though it is not known, knowledge does not cease. It, the unknown ever, knows everything. The Atman is different from the known and unknown, the known being the whole of visible creation and the unknown, the cause of all things, Prakriti. The Atman is above both. It is not to be touched either by the mind or the senses. The Jiva is apt to complain that it does not know the Atman, even as one may doubt and say whether one has a tongue or not. To recognise the Atman-principle in all things, it is necessary to ignore the objectness involved in the process of knowledge, and whenever there is perception or knowledge, every such factor in the capacity of an object should be abandoned, and only the illuminating light of consciousness should be taken for the purpose of analysis and contemplation. This kind of Self-establishment is Atmasakshatkara or realisation of the Atman.

That which remains after the negation of all conditioning factors, such as the five sheaths, is one’s own Self. It is not a void because it knows that it is, and that is Absolute. There is such a thing as self both in worldly parlance and in the universe of philosophy. In ordinary life, by the self one means the personality of the individual, but in the philosophic sense, it is the ultimate metaphysical reality beyond which there is nothing. There cannot be any doubt or dispute about the ultimate Self, for there would be no one to conduct the dispute or argument. No one doubts oneself or denies oneself, and hence the scripture says that one who denies Brahman denies himself, meaning thereby that Brahman cannot be denied. The Atman or Brahman may not be known as an object, but, it being one’s own self, cannot be gainsaid. It is not to be considered as either this or that, because we generally consider what is known by the senses as this, and the Atman is not known by the senses. We consider what is remote as that, and the Atman is not remote, because it is our own self. Hence it cannot be pointed out by any determining article such as this, that, etc. That it is universal, explains everything.

Though the Atman is unknown in an objective sense, it is known in the minimum experience or Aparokshanubhava. It is described in the scripture as Satyam, Jnanam, Anantam, truth, knowledge, infinity. Truth is that which is not contradicted by any other experience. The witnessing consciousness can stand apart as the observer of the cessation of all phenomena, as in the cessation of the experiences of waking, dreaming and deep sleep under different circumstances; but there cannot be a negation or cessation of the Atman itself, because there would then be no observer or knower of the cessation of the Atman. Nor can it be said that there is no observing principle at all, because there is no possibility of an experience without even the barest minimum of intelligence, as when all the contents in a house are removed, something viz., space, remains within, as that which cannot be removed. So, also, when everything of the nature of an object is set aside as the Anatman (not-self), something remains as that which cannot be further emptied out. That is the ultimate minimum of consciousness. Thus, even the total negation of every experience should land finally in something positive and capable of being experienced. The scripture, therefore, having described the nature of all things, takes us along the path of the realisation of the stupendous spiritual Being, by negating all that which is not. Whatever can be designated as this or not this is transcended, and that which cannot be so designated is taken as Reality. Brahman is thus known to be Sat, or Being, and Chit, or experience and consciousness, unconditioned by space, time, causation or objectness (Desa-kala-vastu-parichheda-rahita). Brahman is unlimited in these three ways. When the ideation of creation is withdrawn, the network of space, time and causation also falls from experience. Isvaratva or the idea of God and Jivatva or the idea of the individual arise on account of the perception of the difference between the seer and the seen in this world and the consequent experience of the creator of both the Jiva and the world. These concepts are correlative and will come to a naught with the rise of Self-realisation or Atma-Jnana. (Verses 11-37).

There is a universal determining power, which ordinarily goes by the name of law of nature, hiddenly present in everything in every condition, by which everything is regulated and on account of which things do not overstep their limits and maintain their distinctive features. This law is responsible for the harmony seen in creation: If there were to be no such law, anything could change its nature any time, and one would not be able to determine even the way in which one has to direct one’s actions. There would be catastrophe in the cosmos and chaos created if a governing law were not to exist. It is Brahman reflecting itself through its Sakti or Power that appears as this law and determines the nature of things. Brahman, when it is supposed to be in association with this inscrutable Sakti, is called Isvara, and when it is looked from the point of view of the sheaths, it is called the Jiva. Maya and Avidya are responsible for the designation of Brahman as Isvara and Jiva, as a person may be a father or a grandfather at the same time, to his sons and grandsons. Brahman is called Isvara or Jiva when it is envisaged through Maya or Avidya, and as Maya is pure Sattva, it is universal, and the reflection of Brahman in it is undivided, while Avidya is manifold, and so Jivas are many. When there are no sons or grandsons, there is no father or grandfather and when there is no Maya, or Avidya in the form of sheaths there is no Isvaratva or Jivatva in Brahman. When this truth is meditated upon profoundly with the proper inner qualifications such as the Sadhana-chatushtaya (fourfold ethical means), there comes about realisation of Brahman. The knower of Brahman becomes Brahman itself. Knowing is the same as being in the case of knowledge of Brahman. There is then no rebirth for such knower, for Brahman is unborn. (Verses 38-43)