Our three subtle senses, namely (1) mind, (2) intelligence and (3) ego (thirteen senses in all), are supplied to us by various arrangements of gross or subtle forms of natural energy
SB Canto 2
The Personality of Godhead Lord Śrī Kṛṣṇa is in every living being along with the individual soul. And this fact is perceived and hypothesized in our acts of seeing and taking help from the intelligence.
The general argument of the common man is that since the Lord is not visible to our eyes, how can one either surrender unto Him or render transcendental loving service unto Him? To such a common man, here is a practical suggestion given by Śrīla Śukadeva Gosvāmī as to how one can perceive the Supreme Lord by reason and perception. Actually the Lord is not perceivable by our present materialized senses, but when one is convinced of the presence of the Lord by a practical service attitude, there is a revelation by the Lord's mercy, and such a pure devotee of the Lord can perceive the Lord's presence always and everywhere. He can perceive that intelligence is the form-direction of the Paramātmā plenary portion of the Personality of Godhead. The presence of Paramātmā in everyone's company is not very difficult to realize, even for the common man. The procedure is as follows. One can perceive one's self-identification and feel positively that he exists. He may not feel it very abruptly, but by using a little intelligence, he can feel that he is not the body. He can feel that the hand, the leg, the head, the hair and the limbs are all his bodily parts and parcels, but as such the hand, the leg, the head, etc., cannot be identified with his self. Therefore just by using intelligence he can distinguish and separate his self from other things that he sees. So the natural conclusion is that the living being, either man or beast, is the seer, and he sees besides himself all other things. So there is a difference between the seer and the seen. Now, by a little use of intelligence we can also readily agree that the living being who sees the things beyond himself by ordinary vision has no power to see or to move independently. All our ordinary actions and perceptions depend on various forms of energy supplied to us by nature in various combinations. Our senses of perception and of action, that is to say, our five perceptive senses of (1) hearing, (2) touch, (3) sight, (4) taste and (5) smell, as well as our five senses of action, namely (1) hands, (2) legs, (3) speech, (4) evacuation organs and (5) reproductive organs, and also our three subtle senses, namely (1) mind, (2) intelligence and (3) ego (thirteen senses in all), are supplied to us by various arrangements of gross or subtle forms of natural energy. And it is equally evident that our objects of perception are nothing but the products of the inexhaustible permutations and combinations of the forms taken by natural energy. As this conclusively proves that the ordinary living being has no independent power of perception or of motion, and as we undoubtedly feel our existence being conditioned by nature's energy, we conclude that he who sees is spirit, and that the senses as well as the objects of perception are material. The spiritual quality of the seer is manifest in our dissatisfaction with the limited state of materially conditioned existence. That is the difference between spirit and matter. There are some less intelligent arguments that matter develops the power of seeing and moving as a certain organic development, but such an argument cannot be accepted because there is no experimental evidence that matter has anywhere produced a living entity. Trust no future, however pleasant. Idle talks regarding future development of matter into spirit are actually foolish because no matter has ever developed the power of seeing or moving in any part of the world. Therefore it is definite that matter and spirit are two different identities, and this conclusion is arrived at by the use of intelligence. Now we come to the point that the things which are seen by a little use of intelligence cannot be animate unless we accept someone as the user of or director of the intelligence. Intelligence gives one direction like some higher authority, and the living being cannot see or move or eat or do anything without the use of intelligence. When one fails to take advantage of intelligence he becomes a deranged man, and so a living being is dependent on intelligence or the direction of a superior being. Such intelligence is all-pervading. Every living being has his intelligence, and this intelligence, being the direction of some higher authority, is just like a father giving direction to his son. The higher authority, who is present and residing within every individual living being, is the Superself.
At this point in our investigation, we may consider the following question: on the one hand we realize that all our perceptions and activities are conditioned by arrangements of material nature, yet we also ordinarily feel and say, "I am perceiving" or "I am doing." Therefore we can say that our material senses of perception and action are moving because we are identifying the self with the material body, and that the superior principle of Superself is guiding and supplying us according to our desire. By taking advantage of the guidance of Superself in the form of intelligence, we can either continue to study and to put into practice our conclusion that "I am not this body," or we can choose to remain in the false material identification, fancying ourselves to be the possessors and doers. Our freedom consists in orienting our desire either toward the ignorant, material misconception or the true, spiritual conception. We can easily attain to the true, spiritual conception by recognizing the Superself (Paramātmā) to be our friend and guide and by dovetailing our intelligence with the superior intelligence of Paramātmā. The Superself and the individual self are both spirit, and therefore the Superself and the individual self are both qualitatively one and distinct from matter. But the Superself and the individual self cannot be on an equal level because the Superself gives direction or supplies intelligence and the individual self follows the direction, and thus actions are performed properly. The individual is completely dependent on the direction of the Superself because in every step the individual self follows the direction of the Superself in the matter of seeing, hearing, thinking, feeling, willing, etc.
So far as common sense is concerned, we come to the conclusion that there are three identities, namely matter, spirit and Superspirit. Now if we go to the Bhagavad-gītā, or the Vedic intelligence, we can further understand that all three identities, namely matter, individual spirit, and the Superspirit, are all dependent on the Supreme Personality of Godhead. The Superself is a partial representation or plenary portion of the Supreme Personality of Godhead. The Bhagavad-gītā affirms that the Supreme Personality of Godhead dominates all over the material world by His partial representation only. God is great, and He cannot be simply an order supplier of the individual selves; therefore the Superself cannot be a full representation of the Supreme Self, Puruṣottama, the Absolute Personality of Godhead. Realization of the Superself by the individual self is the beginning of self-realization, and by the progress of such self-realization one is able to realize the Supreme Personality of Godhead by intelligence, by the help of authorized scriptures, and, principally, by the grace of the Lord. The Bhagavad-gītā is the preliminary conception of the Personality of Godhead Śrī Kṛṣṇa, and Śrīmad-Bhāgavatam is the further explanation of the science of Godhead. So if we stick to our determination and pray for the mercy of the director of intelligence sitting within the same bodily tree, like a bird sitting with another bird (as explained in the Upaniṣads), certainly the purport of the revealed information in the Vedas becomes clear to our vision, and there is no difficulty in realizing the Supreme Personality of Godhead, Vāsudeva. The intelligent man therefore, after many births of such use of intelligence, surrenders himself at the lotus feet of Vāsudeva, as confirmed by the Bhagavad-gītā (7.19).