The difference between the gross body and the subtle body is the perishability. Gross body perishes at the end of every birth, whereas the subtle body does not perish and accompanies the casual body and soul till emancipation. All the souls put together is the Brahman. In the same way, all the subtle bodies put together, is known as hiraṇyagarbha or the cosmic egg. Hiraṇyagarbha is endowed with intellect and this intellect, also known as mahat, is the cause for the physical body. Hiraṇyagarbha can be considered as the feminine energy, if soul is considered as the masculine energy. Unless, the soul impregnates hiraṇyagarbha, creation is not possible. This is yet another instance of interdependence in the process of creation. If one assumes the form of his subtle body, he will see two different things on his two sides. On one side, he will find flesh, blood, bones, nerves etc constituting the gross body. This side will be totally dark, except the nine apertures. On the other side, he will notice his casual body in the form of diffused illumination. The illumination of the soul is not fully visible because, it is veiled by ignorance.
Out of the seventeen components of the subtle body, the first five are the organs of perception, also known as organs of knowledge – ear, skin, eye, tongue and nose. They are also known as jñānendriya-s. jñāna means knowledge and indriya means belonging to; therefore jñānendriya-s mean ‘belonging to knowledge’. Since knowledge is acquired through these organs of perception – ear, skin, eye, tongue and nose, they are known as jñānendriya-s. Jñānendriya-s play vital role in acquiring knowledge about the world. The external world is made up of five gross elements ether or ākāś, air, fire, water and earth. The subtle body is made up of tanmātra-s, the subtle forms of these elements. Tanmātra-s look at the gross elements through the five organs of knowledge also known as organs of perception. Unless one has knowledge about the material world, spiritual knowledge cannot be extracted.
Let us take eye as an example. Eyes look at an object, say an apple. The image of the apple is gathered by the aperture in the gross body, in this case, eyes, which in turn pass on the gathered information to the cognitive faculty viz. sight. The action of the organ of perception ceases immediately after it conveyed the information to the cognitive faculty, in this case sight or vision. It is only the vision that provides input to the mind. Organs of perception and cognitive faculties are interdependent. Traffic between the mind and organs of perception is two way through cognitive faculties. Eyes convey the impression of an apple tree to the cognitive faculty sight, which in turn conveys the same to the mind. Mind analyses the impressions of the apple tree and decides to see the fruits of the tree. The desire of the mind is conveyed to the faculty of sight, which in turn gathers information through organs of perception, eyes which look for apples. Therefore, cognitive faculties, also known as knowledge is the intermediary factor between the mind and the organs of perception.
Organs of action are mouth, feet, hands, organ of excretion and organ of procreation. When organs of perception convey the impressions to the mind, mind finally acts only through organs of action. Organs of action are totally in the control of the mind. Desire, created through the influence of organs of perception is executed by the mind through the organs of action, also known as karmendriya-s. Inherently, mind is attracted more towards organs of perception as they communicate innumerable worldly impressions to the mind and the mind is too happy to enjoy these impressions. But, organs of action cannot communicate anything to the mind. They can only receive commands from the mind. Traffic between mind and organs of action is always one way.
Let us continue with the example of an apple. Ego is an inherent factor of the mind. I or me or mine arise only because of ego. At the instance of the mind, eyes again look at the apple tree and this time more specifically for apple fruits. Organ of perception, eye conveys to the mind through cognitive faculty, sight about the availability of the apple fruit in the tree. If mind is in confusion, it refers to the intellect. Intellect confirms to the mind that it is apple. Then the mind develops desire because of the inherent ego. The desire develops in the form of tasting an apple. Now mind sends command to organs of action to get the apple. Receiving the command from the mind, feet moves towards the apple tree, hands pluck an apple and mouth eats it. The cause for the movement of legs and hands is prāṇa and its five modifications. Thus the seventeen components form the subtle body.