Energy can neither be created nor be destroyed, and so is the Soul.
Lord Krishana has explained the existence of soul in Gita.
As said in the Svetäsvatara Upanishad (5.9) :
बालाग्रशतभागस्य शतधा कल्पितस्य च |
भागो जीवः स विज्ञेयः स चानान्त्यायकाल्पते ||
Which means :
“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 soul.”
In modern science that would be of the order of sub-atomic size.
Soul is nothing but energy. It is the energy that keeps us moving. It is the energy by virtue of which we can feel the air, the water, the touch of a body, warmth of the sun, coldness of the moon.
This symptom of the soul’s presence is perceived as individual consciousness.
And when this soul is gone, there is no energy to move, the consciousness of the body is no more. The body can not move, It can not hear, It can not feel.
And this is Death.
Lord Krishna has also said that soul can not be destroyed by any means. It travels from one body to another, without getting older. When it leaves a body, the person is dead and when it attains a different body, a new child is born.
The soul of a human is same as that of an animal or that of a tree or any other living body, let it be the smallest insect on the earth or the fishes in the water.
An analogy can be drawn with a law of modern science – 1st law of thermodynamics.
“Energy can neither be created nor be destroyed, but can be transformed from one form to another.”.
I wonder if we could ever prove this scientifically…
Soul is energy.
It can neither be created nor destroyed. It can only be transformed from one form to other. And when this soul is gone, there is no energy to move, the consciousness of the body is no more. The body can not move, It can not hear, It can not feel — And this is Death.
But why does a man die?
Is it inevitable?
Why does the soul leave the body?
Who decides that it is the time for soul to leave a body, and that now is the appropriate time to attain a different body?
Does soul makes this decision?
Can a soul think?
Is there some one who commands the soul?
Soul travels just like any other form of energy. Let it be heat, wind or electricity. Energy always tends to flow from a high potential to low potential.
Every living body can be imagined to exist at a definite energy potential. This potential is dependent on many factors. The value of this potential increases with time. Thus, soul always tries to escape from one body to attain another body with lower potential. However, there is a threshold. A soul can leave only when this barrier is crossed and it tries to attain a body with minimum energy potential. And hence, it always attains the body of a new born.
Since this energy potential is dependent on many factors, some die when they are old and some die when they are young. Some die of natural cause and some die because of disease. Some die on roads and some in wars. Some people kill themselves and some are killed. The rate of change of this energy potential is always positive and hence death is inevitable.
Transformation of energy from one form to another is necessary. This phenomenon makes electricity, quenches thirst and is responsible for functioning of this world. Similarly the soul should travel from one body to other for smooth functioning. This travel of soul from one body to other is just a small part of the big machine that governs this universe.
Hence there is no need to mourn over a dead body, because a new body is born. The soul still lives as it did before.