When we begin to reflect on life and existence, we first observe that we are born of Matter and that at some point, life is infused into the physical form, and at some point, it departs and the form disintegrates. Is this the entirety of what is taking place? The Kena Upanishad implies that there is something greater and deeper that is the actual life that creates, permeates and controls the life we experience.
Verse 8: “That which breathes not with the breath, that by which the life-breath is led forward in its paths, know That to be the Brahman and not this which men follow after here.”
Sri Aurobindo comments: “But the Brahman-consciousness is not only Mind of our mind, Speech of our speech, Sense of our sense; it is also Life of our life. In other words, it is a supreme and universal energy of which our own material life and its sustaining energy are only an inferior result, a physical symbol, an external and limited functioning. That which governs our existence and its functionings, does not live and act by them, but is their superior cause and the supra-vital principle out of which they are formed and by which they are controlled.”
“The English word life does duty for many very different shades of meaning; but the word Prana familiar in the Upanishad and in the language of Yoga is restricted to the life-force whether viewed in itself or in its functionings. The popular significance of Prana was indeed the breath drawn into and thrown out from the lungs and so, in its most material and common sense, the life or the life-breath; but this is not the philosophic significance of the word as it is used in the Upanishads. The Prana of the Upanishads is the life-energy itself which was supposed to occupy and act in the body with a fivefold movement, each with its characteristic name and each quite as necessary to the functioning of the life of the body as the act of respiration. Respiration in fact is only action of the chief movement of the life-energy, the first of the five, — the action which is most normally necessary and vital to the maintenance and distribution of the energy in the physical frame, but which can yet be suspended without the life being necessarily destroyed.”
“The existence of a vital force or life-energy has been doubted by western Science, because that Science concerns itself only with the most external operations of Nature and has as yet no true knowledge of anything except the physical and outward. This Prana, this life-force is not physical in itself; it is not material energy, but rather a different principle supporting Matter and involved in it. It supports and occupies all forms and without it no physical form could have come into being or could remain in being. It acts in all material forces such as electricity and is nearest to self-manifestation in those that are nearest to pure force; material forces could not exist or act without it, for from it they derive their energy and movement and they are its vehicles. But all material aspects are only field and form of the Prana which is in itself a pure energy, their cause and not their result. It cannot therefore be detected by any physical analysis; physical analysis can only resolve for us the combinations of those material happenings which are its results and the external signs and symbols of its presence and operation.”
Sri Aurobindo, The Upanishads, Kena Upanishad and analysis, pg. 102, 156-160