The etheric body is a web of light energy, impulsed or motivated by the type or the quality of the energies to which it responds, from the angle of evolutionary development. It might be stated that:
· Unevolved or savage man responds simply to prana or physical energy, vitalising the appetites of the lower nature, developing the instincts and thus laying the foundation of a physical vehicle as the outer garment of the soul. At this stage, intellect is embryonic; the physical appetites and the five senses are dominating factors. All this is due to the activity of prana as it pours through the etheric or vital body.
· Average man is impulsed by desire which is an energy, emanating from world desire and which—developing or organising the astral body—generates desire-energy. It pours into the vital body and galvanises physical man into those activities which will lead to the satisfaction of desire. This is a parallel process to the work of prana, impelling the animal instinctive nature into activity. These necessarily parallel and produce conflict—the first clash (within the man) of the pair of opposites. Gradually, the pranic energy becomes automatic in its activity; the shift of the consciousness is into the astral or desire body and the functioning of the instinctual nature drops below the threshold of the consciousness. Man then focusses his life in the astral vehicle and his etheric body becomes animated by the potent inflow of desire-energy.
· The developed man, with an integrated personality, gradually brings the etheric body under the control of mental energy and his physical plane activity is not then so much implemented by instinct or desire as by thought energy, dedicated to and expressing the nature of the man's plan. This plan indicates increasingly his intelligent desire—selfish in the early stages, complex and dualistic in the intermediate stages but slowly responding to the world plan and to the divine intent for humanity.
· Finally, when the power of the Triangles (the spiritual name given in The Secret Doctrine to the soul) is being imposed upon the personality, then their energy supersedes the other energies and the personality—focussed now in the mind and responsive to soul impression—expresses upon the physical plane, through the medium of the physical brain and the body, the intent, potency and nature of the all-inclusive soul.