One of the basic ideas of the Lord Buddha is anatman "not-self" or the illusion of "self". So Buddhism denies the existence of a permanent or static entity like a soul but teaches about a stream of consciousness. Also the Buddha did not talk about God. So merging with God was not a teaching of the Lord Buddha.
Even within Buddhism, there are two opinions on 'anataman'. 'Theravada Buddhism' & 'Mahayana Buddhism'. If consciousness exists, then soul must exist just like if light exists, the source of light must exist.
Bhagvad Gita teaches us about soul:
avināśi tu tad viddhi
yena sarvam idaḿ tatam
vināśam avyayasyāsya
na kaścit kartum arhati
That which pervades the entire body you should know to be indestructible. No one is able to destroy that imperishable soul.B.G.2.17
This verse more clearly explains the real nature of the soul, which is spread all over the body. Anyone can understand what is spread all over the body: it is consciousness. Everyone is conscious of the pains and pleasures of the body in part or as a whole. This spreading of consciousness is limited within one's own body. The pains and pleasures of one body are unknown to another. Therefore, each and every body is the embodiment of an individual soul, and the symptom of the soul's presence is perceived as individual consciousness. This soul is described as one ten-thousandth part of the upper portion of the hair point in size.
The Śvetāśvatara Upaniṣad (5.9) confirms this:
bālāgra-śata-bhāgasya
śatadhā kalpitasya ca
bhāgo jīvaḥ vijñeyaḥ
sa cānantyāya kalpate
"When the upper point of a hair is divided into one hundred parts and again each of such parts is further divided into one hundred parts, each such part is the measurement of the dimension of the spirit soul."
Similarly the same version is stated:
keśāgra-śata-bhāgasya
śatāḿśaḥ sādṛśātmakaḥ
jīvaḥ sūkṣma-svarūpo 'yaḿ
sańkhyātīto hi cit-kaṇaḥ
"There are innumerable particles of spiritual atoms, which are measured as one ten-thousandth of the upper portion of the hair."[Cc. Madya 19.140]
Therefore, the individual particle of spirit soul is a spiritual atom smaller than the material atoms, and such atoms are innumerable. This very small spiritual spark is the basic principle of the material body, and the influence of such a spiritual spark is spread all over the body as the influence of the active principle of some medicine spreads throughout the body. This current of the spirit soul is felt all over the body as consciousness, and that is the proof of the presence of the soul. Any layman can understand that the material body minus consciousness is a dead body, and this consciousness cannot be revived in the body by any means of material administration. Therefore, consciousness is not due to any amount of material combination, but to the spirit soul.
In the Muṇḍaka Upaniṣad (3.1.9) the measurement of the atomic spirit soul is further explained:
eṣo 'ṇur ātmā cetasā veditavyo
yasmin prāṇaḥ pañcadhā saḿviveśa
prāṇaiś cittaḿ sarvam otaḿ prajānāḿ
yasmin viśuddhe vibhavaty eṣa ātmā
"The soul is atomic in size and can be perceived by perfect intelligence. This atomic soul is floating in the five kinds of air (prāṇa, apāna, vyāna, samāna and udāna), is situated within the heart, and spreads its influence all over the body of the embodied living entities. When the soul is purified from the contamination of the five kinds of material air, its spiritual influence is exhibited."
The haṭha-yoga system is meant for controlling the five kinds of air encircling the pure soul by different kinds of sitting postures not for any material profit, but for liberation of the minute soul from the entanglement of the material atmosphere.
So the constitution of the atomic soul is admitted in all Vedic literatures, and it is also actually felt in the practical experience of any sane man. Only the insane man can think of this atomic soul as all-pervading viṣṇu-tattva.
The influence of the atomic soul can be spread all over a particular body.
According to the Muṇḍaka Upaniṣad, this atomic soul is situated in the heart of every living entity, and because the measurement of the atomic soul is beyond the power of appreciation of the material scientists, some of them assert foolishly that there is no soul.
Jesus said
"I and the Father are one." John 10:30
Bhagvad Gita teaches us:
na tv evāhaḿ jātu nāsaḿ
na tvaḿ neme janādhipāḥ
na caiva na bhaviṣyāmaḥ
sarve vayam ataḥ param
Never was there a time when I did not exist, nor you, nor all these kings; nor in the future shall any of us cease to be.
B.G. 2.12
In the Vedas, in the Kaṭha Upaniṣad as well as in the Śvetāśvatara Upaniṣad, it is said that the Supreme Personality of Godhead is the maintainer of innumerable living entities, in terms of their different situations according to individual work and reaction of work. That Supreme Personality of Godhead is also, by His plenary portions, alive in the heart of every living entity. Only saintly persons who can see, within and without, the same Supreme Lord can actually attain to perfect and eternal peace.
nityo nityānāḿ cetanaś cetanānām
eko bahūnāḿ yo vidadhāti kāmān
tam ātma-sthaḿ ye 'nupaśyanti dhīrās
teṣāḿ śāntiḥ śāśvatī netareṣām
The same Vedic truth given to Arjuna is given to all persons in the world who pose themselves as very learned but factually have but a poor fund of knowledge. The Lord says clearly that He Himself, Arjuna and all the kings who are assembled on the battlefield are eternally individual beings and that the Lord is eternally the maintainer of the individual living entities both in their conditioned and in their liberated situations. The Supreme Personality of Godhead is the supreme individual person, and Arjuna, the Lord's eternal associate, and all the kings assembled there are individual eternal persons. It is not that they did not exist as individuals in the past, and it is not that they will not remain eternal persons. Their individuality existed in the past, and their individuality will continue in the future without interruption. Therefore, there is no cause for lamentation for anyone.
The Māyāvādī theory that after liberation the individual soul, separated by the covering of māyā, or illusion, will merge into the impersonal Brahman and lose its individual existence is not supported herein by Lord Kṛṣṇa, the supreme authority. Nor is the theory that we only think of individuality in the conditioned state supported herein. Kṛṣṇa clearly says herein that in the future also the individuality of the Lord and others, as it is confirmed in the Upaniṣads, will continue eternally. This statement of Kṛṣṇa's is authoritative because Kṛṣṇa cannot be subject to illusion. If individuality were not a fact, then Kṛṣṇa would not have stressed it so much even for the future. The Māyāvādī may argue that the individuality spoken of by Kṛṣṇa is not spiritual, but material. Even accepting the argument that the individuality is material, then how can one distinguish Kṛṣṇa's individuality? Kṛṣṇa affirms His individuality in the past and confirms His individuality in the future also. He has confirmed His individuality in many ways, and impersonal Brahman has been declared to be subordinate to Him. Kṛṣṇa has maintained spiritual individuality all along; if He is accepted as an ordinary conditioned soul in individual consciousness, then His Bhagavad-gītā has no value as authoritative scripture. A common man with all the four defects of human frailty is unable to teach that which is worth hearing. The Gītā is above such literature. No mundane book compares with the Bhagavad-gītā. When one accepts Kṛṣṇa as an ordinary man, the Gītā loses all importance. The Māyāvādī argues that the plurality mentioned in this verse is conventional and that it refers to the body. But previous to this verse such a bodily conception is already condemned. After condemning the bodily conception of the living entities, how was it possible for Kṛṣṇa to place a conventional proposition on the body again? Therefore, individuality is maintained on spiritual grounds and is thus confirmed by great ācāryas like Śrī Rāmānuja and others. It is clearly mentioned in many places in the Gītā that this spiritual individuality is understood by those who are devotees of the Lord. Those who are envious of Kṛṣṇa as the Supreme Personality of Godhead have no bona fide access to the great literature. The nondevotee's approach to the teachings of the Gītā is something like that of a bee licking on a bottle of honey. One cannot have a taste of honey unless one opens the bottle. Similarly, the mysticism of the Bhagavad-gītā can be understood only by devotees, and no one else can taste it, as it is stated in the Fourth Chapter of the book. Nor can the Gītā be touched by persons who envy the very existence of the Lord. Therefore, the Māyāvādī explanation of the Gītā is a most misleading presentation of the whole truth. Lord Caitanya has forbidden us to read commentations made by the Māyāvādīs and warns that one who takes to such an understanding of the Māyāvādī philosophy loses all power to understand the real mystery of the Gītā. If individuality refers to the empirical universe, then there is no need of teaching by the Lord. The plurality of the individual soul and of the Lord is an eternal fact, and it is confirmed by the Vedas as above mentioned.
