The greatest disease in the minds of the scientists is that they do not believe that something is a fact unless it is proved by scientific experiments. When a scientist makes a statement and he supports that statement with scientific experiments, everyone is completely convinced, and no questions are asked. When we talk about the spirit soul to these scientists, their usual response is, “How can one detect the presence of the soul?” Because they have been conditioned to working with machines, they wonder whether the soul can be detected by scientific experiments. However, scientists have to agree that even in their own scientific realm there are many facts that cannot be proved by experiments. The fact is that the soul is there, but in order to understand its existence we have to accept knowledge from the right person, Śrī Kṛṣṇa, or God, and His representative in disciplic succession, the spiritual master.
Everyone in the scientific community knows that mathematicians work with an imaginary number called “i,” which is the square root of minus one. This number does not figure among the natural numbers (1,2,3, etc.).
However, important branches of mathematics-for example, the theory of analytical functions-are based on this imaginary unit. Without the help of this branch of mathematics, various complex theories and problems cannot be solved. Thus the existence of this number cannot be denied; yet there is no experiment to prove it. In a similar manner, scientists in the field of statistical mechanics also utilize various conceptual models-ensembles, for example-to explain their theories and arguments. These are all beyond the realm of experimental science. If scientists are willing to accept these imaginary and conceptual models, what is the difficulty in accepting the perfect knowledge given by Lord Kṛṣṇa, the supreme scientist?
Another scientific theory that is beyond the limit of experimental science is Heisenberg’s uncertainty principle. The statement of this principle is that it is impossible to simultaneously determine the position and momentum of any object. In mathematical language, it is stated that the product of the uncertainties in the measured values of the position and momentum (product of mass and velocity) cannot be smaller than Planck’s constant. No existing experimental technique can prove this principle. However, scientists all over the world accept this statement as a fact, knowing that the experimental proof is beyond their ability. Similarly, there is no scientific experiment to prove the Third Law of Thermodynamics. This law, as formulated by Planck, states that the entropy of a perfect crystal at absolute zero degrees is equal to zero. Factually, there is no means available for measuring directly the absolute entropies. Therefore the proof of this law is beyond the realm of experimental science.
It is also to be noted that so-called scientific theories are changing constantly. For example, at the beginning of the Nineteenth Century (1808), John Dalton, in developing his atomic theory, stated that atoms could not be further divided. However, toward the end of the Nineteenth Century and the beginning of the Twentieth Century, it was found that Dalton’s atomic theory could no longer be considered correct. It was observed that atoms could be further divided into fundamental particles like electrons, protons and neutrons. It was also found that some atoms could emit alpha and beta particles, thereby producing new atoms, and so on. As a matter of fact, the so-called nuclear bombs are a result of these findings. In a similar manner, during the Eighteenth and Nineteenth Centuries Newton’s mechanics had a tremendous influence on the minds of scientists, since they could be applied to gross material objects. However, at the beginning of the Twentieth Century, with the discoveries of the fundamental particles, it was realized that Newton’s mechanics failed in describing the motions of these particles. Thus quantum mechanics has been developed to explain the phenomena they exhibit. These theories are filled with speculation, and they are also changing. Just as past and present scientific theories are changing, so we can understand that future scientific theories will also change.
This simply shows that the brains of the highly honored material scientists are imperfect, and, as a result, the theories proposed by these brains will always be imperfect. Actually, perfect knowledge cannot be changed. In order to get perfect knowledge, one has to take knowledge from the perfect scientist, Lord Kṛṣṇa, and His bona fide representative, the spiritual master. Kṛṣṇa says:
“I am the source of all spiritual and material worlds. Everything emanates from Me. The wise who know this perfectly engage in My devotional service and worship Me with all their hearts.”[Bg. 10.8]
“Of all creations I am the beginning and the end and also the middle, O Arjuna. Of all sciences I am the spiritual science of the Self, and among logicians I am the conclusive truth.”[Bg. 10.32]
Scientists have to understand that the knowledge and ability they have is extremely limited and in fact quite insignificant. With this insignificant and limited knowledge, how will it be possible to understand knowledge beyond the material context? Actually there is no question about the existence of the soul. The living entities are fragmental spirit souls, whereas Lord Kṛṣṇa is the supreme soul, supreme person and supreme scientist. Kṛṣṇa says:
“The living entities in this conditioned world are My eternal, fragmental parts. Due to conditioned life, they are struggling very hard with the six senses, which include the mind.”[Bg. 15.7]
“It should be understood that all species of life, O son of Kuntī, are made possible by birth in this material nature, and that I am the seed-giving father.”[Bg. 14.4]
Just as the existence of air can be felt by touch and the existence of certain molecules by fragrance and aroma, similarly consciousness is the clear symptom of the existence of the soul.
“O son of Bharata, as the sun alone illuminates all this universe, so does the living entity, one within the body, illuminate the entire body by consciousness.”[Bg. 13.34]
Biologists also confirm that even the smallest microorganisms, such as bacteria, have consciousness. When consciousness enters into a material body. we call it a living body. However, when there is no consciousness in the body-in other words, when the spirit soul leaves the body-simply a lump of matter is left over. This phenomenon we call death. Therefore the spirit soul never dies and is never born. It is eternal. What we call birth and death are nothing but the changing of different material bodies, the replacement of old bodies with new ones.
“The living entity in the material world carries his different conceptions of life from one body to another as the air carries aromas.”[Bg. 15.8]
Thus birth, death, old age and disease are the signals of the changing of the material body.
When our scientific friends readily accept Heisenberg’s uncertainty principle, the imaginary unit and the various conceptual models of statistical mechanics, which are all beyond experimental science, what is the difficulty in accepting the existence of the spirit soul? The supreme scientist Śrī Kṛṣṇa says:
“For the soul there is never birth nor death. Nor, having once been, does he ever cease to be. He is unborn, eternal, ever-existing, undying and primeval. He is not slain when the body is slain.”[Bg. 2.20]
Its size has been described thus: “When the upper point of a hair is divided into one hundred parts and again each of such parts is divided into one hundred parts, each such part is the measurement of the dimension of the spirit soul.“
Scientists are familiar with the law of conservation of energy which states that energy can be neither created nor destroyed. The living entities are the superior energy of the Supreme Lord, Śrī Kṛṣṇa. Therefore the soul is eternal.
The nature of the spirit soul is elaborately described in the Second and Thirteenth Chapters of Bhagavad-gītā. One simply has to take the knowledge from the supreme scientist, Śrī Kṛṣṇa, the speaker of Bhagavad-gītā.