Upaniṣad-s say that Brahman is situated in the heart and this means that Brahman is small and has only a small Abode. This aphorism explains why Brahman is said to be smaller than the smallest and resides in one’s heart. Chāndogya Upaniṣad (III.xiv.3) says, “The Self is inside the heart, smaller than a grain of rice.” The argument is based on this saying of Upaniṣad. The same Upaniṣad again says, “He is bigger than the three regions” The three regions three vyāhṛti-s of Gayatri mantra viz. bhūr, bhuvaḥ and svar, the three worlds or three mystical planes. Both these references are in the same verse. The same concept is also conveyed in Kaṭha Upaniṣad (I.ii.20) which says,”He is bigger than the biggest and smaller than the smallest.” Why is it said so? There could be two answers. One, Brahman is omnipresent and naturally He exists in an atom as well as in a mountain. It is not right to say that He exists in atom. The correct usage would be He exists as atoms and simultaneously He exists as mountains. He alone can exist simultaneously in more than one place. This is His omnipotence, His very nature. Secondly, His smaller side is revealed to us to enable us to visualize Him during meditation. When Kṛṣṇa showed His Cosmic form (viśvarūpa), Arjuna could not see this for long, due to fear. Similarly, if the Cosmic form of Brahman is verbally described in Upaniṣad-s, out of fear alone, we will not contemplate this form. This is the reason why Upaniṣad-s say He is bigger than the biggest and smaller than the smallest.
A seed can be explained as a seed today and after some years, the same seed is not there. The seed has grown into a big tree. Simultaneously, either a seed or a tree alone can exist. This is known as growth or modification. When there is growth, destruction is always there. But Brahman can exist as a seed and a tree simultaneously, because He is beyond growth. He is projected in various forms only to enable us to contemplate Him in order to merge with Him.
When Brahman is omnipresent and exists in all the beings as the Self, He also experiences the pleasure and pain of the embodied form. Bṛhadāraṇyaka Upaniṣad (III.vii.23) counters this argument by saying, “He is never known, but is the Knower. There is no other witness but Him...”
Brahman though is present as the Self within, does not partake in an action or cause any action of the embodied person. He remains only as a witness. That is why Upaniṣad said that He is never known because He has no shape or form. How can He be contemplated without a form? For the purpose of knowing Him, He is projected as the rays of the sun and not in the form of the sun itself, as if we look at the sun, our eyes will be blinded. Our actions are based on our karmas and not due to the inducement of the Self within. When the body and mind suffers, He only remains as a witness. He is in no way involved in any of the actions of the body and mind.
We consume food, the embodied form consumes food. But who takes this food? Is it the Self or jaṭharāgni (the digestive fire in the stomach). When we say that jaṭharāgni is the eater of the food, it leads to dualism and gives room to believe that there is something or someone apart from Brahman, who consumes the food we take. It is said that jaṭharāgni is not different Brahman; it is also Brahman. Like all rivers merging into ocean, all the food we consume also merges into Brahman or absorbed by Brahman. If the food is taken or not taken, Brahman always remains the same, as He also exists in the form of food. Does this mean that Brahman eats? No, obviously Brahman cannot eat, as He is food itself. How can food eat food?
Why food is consumed by an embodied form? Food leads to growth and growth ends up at death. If a man eats food, he grows only to die ultimately. If Brahman eats food (only for the purpose of understanding), He does not grow and naturally there is no death. If we don’t eat, we die, whereas if Brahman does not eat, He does not die, as He is beyond modifications. This aphorism says that both sentient and insentient are Brahman only. There is no second to Him or nothing is different from Him. Everything is Brahman.
There is difference between a Self-realized person and an ordinary person. Difference is in one’s perception. Perception depends upon spiritual knowledge. Why the perception differs and how it is related to spiritual knowledge? An ordinary person looks at the world as duality. He sees the world from his own eyes. When he sees the world with his own eyes, the world appears different from him. This is dualism, because there are two objects, the seer and the seen. Practically speaking, through all of us talk about Advaita, it is not sincerely followed. It is extremely difficult to follow the revelations of Advaita philosophy. One needs to have faith, will and practice. Generally they don’t work in tandem and there is always some deficiency on any of these. Sync between these three can happen only if karmic account permits.
Let us analyze this through Kaṭha Upaniṣad (I.ii.18). It says, “The Self is not born nor does it die. It is not born of something, nor is something else born of it. It is without birth, eternal, unchanging. The body dies, but not the Self.” Again the Upaniṣad (II.i.2) says, “Immature people run after external objects and they get caught in the net of death. But wise men know where immortality is and that is why they reject everything in the world, knowing well that they are short lived (pleasures are short lived).”
This clearly goes to prove that Brahman is beyond birth and death and also the one who knows Brahman, as He is, is also beyond birth and death. This is the reason, why we seek Him in the midst of our hectic worldly activities. Even if we don’t realize Him in this birth due to our karmic account, we recommence our spiritual journey from the level we have attained in this birth.
Both the Self (Brahman) and the self (individual soul) are in the same cavity of the heart. Though the difference between the Self and the self was discussed earlier, Brahma Sūtra clearly establishes similarities and differences between the two. What is the difference between the two? The Self is pure and is inside the self. Kaṭha Upaniṣad (.iii.1) explains this further. It says, “Those who know Brahman say that the Cosmic Self and the individual self are like Light and its shadow.” The difference between light and shadow is that the former is pure and later is dark and impure. But without the light, shadow is not possible. Similarly, Brahman is Pure and the individual self is dark as the Self within the individual self is covered by the veil of māyā. We have already seen this as the sun behind dark clouds. Just because dark clouds obstruct the brightness of the sun, it does not mean that sun is not bright and illuminating. In the same manner, even if the Self is veiled by māyā, it does not mean that the Self is not omnipresent. Without the existence of the Self, how can māyā cast a veil on the Self? The concept of cause and effect is being introduced gradually.
Taittirīya Upaniṣad (II.1) says, “Brahman is in the space within the heart, which is like a cave.” Cave means darkness, which refers to the darkness of māyā. We are not able to realize the effulgence of the Self within, because it is in hidden beneath the darkness of māyā, which is explained as the cave. When we go past māyā, we are able to realize the effulgence of the Self. This is Self realization.
At this level, we are able to distinguish between the Self and the self. Having known the difference, the hidden Self can be realized only through adequate spiritual knowledge and practice. Unless the individual self is fully understood, how can the Self within the individual self can be realized. In order to overcome this, Kaṭha Upaniṣad (I.iii.3) explains the connection between the self on one hand and mind, intellect and body on the other hand. Unless this relationship is properly understood, the self cannot be understood, leave alone the Self. “Individual soul is the master of the chariot. The chariot (the physical body) belongs to him. He has purchased the chariot (through his karmic account). The master is sitting inside the chariot. The chariot needs a driver who can drive the chariot and this is intellect (buddhi). We have the master who owns the chariot and the driver, but how to make the horse run? In order to make the horse run, reins (stop or slow up one's horse or oneself by or as if by pulling the reins) are needed and reins are compared to the mind. What is the work of the master? Nothing, he simply sits and is not involved in running the chariot and this is the individual soul. But it is the master who decides the destination and therefore, both intellect and mind work according to the wishes of the self, who is the master. Is it not contrary to what has been said earlier? It is not contradictory, as there is difference between the Self and the self. Individual self is covered by māyā and as long as māyā prevails, karmic account also prevails. It is the karmic account that determines the course of action by afflicting the mind. Thus, the master within asks the intellect (the driver) to go to particular place and the intellect in turn commands the mind (reins) to move in that direction. If one wants to attain liberation he can do so and if one does not want to attain liberation and wants to remain with the material world, he can also do so. Which decides this? Mind in combination with one’s karmic account.