Srila Prabhupada in this wonderful excerpt from a class on the Bhagavad-gita as it is explains how to develop a thorough understanding of the soul as personal and possessing senses.
Happiness we feel through our senses. Because material, dead stone, has no sense, therefore dead stone cannot feel happiness or distress. Now, this consciousness, the developed consciousness, feels happiness and distress more than undeveloped consciousness.
Just like the trees. The trees, they have got also consciousness, but it is not developed consciousness. Therefore the trees are standing on the road or anywhere, but they have no sense of feeling the miseries. Now, suppose a human being is asked to stand like the tree, at least for three days. Oh, it will be impossible for him because he cannot tolerate such kind of miseries. So therefore conclusion is that every living entity feels the pleasure and happiness according to the developed consciousness of his being. Similarly, the happiness which we are feeling now in the material mixture, that is not real happiness. That is not real happiness. If you ask the tree, "Are you feeling happy?" the tree will say, "Yes. I am feeling happy standing here the whole year, and the wind and snowfall I am enjoying very much." Oh. You see? So that sort of happiness the tree may enjoy, but you are human being. You will say, "Oh, this is the standard of his enjoyment."
Similarly, there are different kinds and different grades of living entities. Their standard of feeling happiness and miseries are also different grades. Animal. In the animal kingdom, they have no sense. One animal is being slaughtered. The other animal is seeing because he has no knowledge the next turn is he is being turned..., being slaughtered, but he is chewing some grass. He is happy. He is thinking that "I am happy." Next moment it will be slaughtered, but he does not know. So these are all different grades of happiness. But the highest standard of happiness is described here, sukham atyantikam yat tad buddhi-grahyam atindriyam [Bg. 6.21]. Buddhi-grahyam atindriyam. Buddhi means intelligence. One has to be intelligent. If you want to enjoy life, then you must be intelligent also. Just like the animals, they are not intelligent enough. Therefore they cannot enjoy life as a human being can, standard. So here, in the Bhagavad-gita also, it is said that buddhi-grahyam atindriyam.
Atindriyam. Now, just take the example of a dead man. The senses, the hands, the nose, the sense organs, and everything is there, but now he cannot enjoy. The dead body, it cannot enjoy. Why? This requires intelligence. Why the dead body cannot enjoy? What is the difference? The body is lying there. The hands and the nose and the legs and the eyes and all other sense organs are there. But why the dead body cannot enjoy? That requires intelligence. That means that the enjoying energy, the spiritual spark, that has gone away. Therefore it has no power to enjoy. Then, if you make advance further with intelligence, then you will understand that actually the body was not enjoying, but that little spark, spiritual spark, that was enjoying, not this body. This requires little intelligence. I am thinking that "I am enjoying with my sense organs," but you are not enjoying. The real enjoyer is that small spiritual spark within you. That spiritual spark has got the potency of enjoyment, but that is not being manifested on account of being covered by this material tabernacle, and therefore this enjoyment is not perfect.
This requires little intelligence, that "Where is the enjoyment for the dead body?" The dead body no more can enjoy. Suppose if a man is offered a dead body of a beautiful woman, will he accept? Or a woman is offered the dead body of a beautiful man, will she accept? No. Because that enjoying spark is moved now. That requires intelligence. Who is enjoying? Who is enjoying? The enjoying, the enjoying spirit. The spirit is enjoying, not this body. That requires intelligence. Then again... Now, if that spirit is enjoying, then the spirit must have enjoying senses also. Otherwise how it can enjoy? If you have no enjoying sense organ, then how you can enjoy? A blunt cannot enjoy. Therefore it is accepted that the spirit soul, although it is very small, atomic, we cannot measure... Several times I have repeated here that the measurement of the small, infinitesimal spirit spark is just one ten-thousandth part of the upper portion of your hair. It is so small. But that does not mean... Just like we are incapable to measure something. We define that "Point has no length, no breadth," but actually it is not a fact. If you see a point with microscope, you'll find the point has increased to one inch round, and it has got length and breadth. Similarly, we have no capacity to make a measurement of the soul, but there is measurement.
And there are senses of that spiritual spark. There are. Without having this... Without the spiritual spark having the senses, how this body is grown? This body is just like dress. When we speak of dress, the dress is made according to your body. If you go to a tailor, the tailor will take measurements of your body and the dress will be supplied to you, fit. Similarly, unless that spiritual spark has got body, how this, I mean to say, dress of this material tabernacle has grown? This requires intelligence.
So the conclusion is that that spiritual spark is not impersonal. It is actually personal. The soul is actual person. As God is actual, personal, similarly, because we are part and parcel of the Supreme, therefore, if I am a person, then God must be person. God is the father of everyone. Now, if I am the son -- I have got personality; I have got individuality -- how can you deny the individuality and personality of the Supreme Lord?
Bhagavad-gita 6.21-27 -- New York, September 9, 1966