H. P. Blavatsky
Now, since the metaphysics of Occult physiology and psychology postulate within mortal man an immortal entity, “divine Mind,” or Nous, whose pale and too often distorted reflection is that which we call "Mind" and intellect in men — virtually an entity apart from the former during the period of incarnation — we say that the two sources of "memory" are in these two "principles." These two we distinguish as the Higher Manas (Mind or Ego), and the Kama-Manas, i.e., the rational, but earthly or physical intellect of man, incased in, and bound by, matter, therefore subject to the influence of the latter: the all-conscious SELF, that which reincarnates periodically — verily the WORD made flesh! — and which is always the same, while its reflected “Double,” changing with every new incarnation and personality, is, therefore, conscious but for a life-period. The latter “principle” is the Lower Self, or that, which manifesting through our organic system, acting on this plane of illusion, imagines itself the Ego Sum, and thus falls into what Buddhist philosophy brands as the “heresy of separateness.” The former, we term INDIVIDUALITY, the latter Personality. From the first proceeds all the noetic element, from the second, the psychic, i.e., “terrestrial wisdom” at best, as it is influenced by all the chaotic stimuli of the human or rather animal passions of the living body.
The “Higher EGO” cannot act directly on the body, as its consciousness belongs to quite another plane and planes of ideation: the “lower” Self does: and its action and behavior depend on its free will and choice as to whether it will gravitate more towards its parent (“the Father in Heaven”) or the “animal” which it informs, the man of flesh. The “Higher Ego,” as part of the essence of the UNIVERSAL MIND, is unconditionally omniscient on its own plane, and only potentially so in our terrestrial sphere, as it has to act solely through its alter ego — the Personal Self. Now, although the former is the vehicle of all knowledge of the past, the present, and the future, and although it is from this fountain-head that its “double” catches occasional glimpses of that which is beyond the senses of man, and transmits them to certain brain cells (unknown to science in their function), thus making of man a Seer, a soothsayer, and a prophet; yet the memory of bygone events — especially of the earth earthy — has its seat in the Personal Ego alone. No memory of a purely daily-life function, of a physical, egotistical, or of a lower mental nature — such as, e.g., eating and drinking, enjoying personal sensual pleasures, transacting business to the detriment of one’s neighbor, etc., etc., has ought to do with the “Higher” Mind or EGO. Nor has it any direct dealings on this physical plane with either our brain or our heart — for these two are the organs of a power higher than the Personality — but only with our passional organs, such as the liver, the stomach, the spleen, etc. Thus it only stands to reason that the memory of such-like events must be first awakened in that organ which was the first to induce the action remembered afterwards, and conveyed it to our “sense-thought,” which is entirely distinct from the “supersensuous” thought. It is only the higher forms of the latter, the superconscious mental experience, that can correlate with the cerebral and cardiac centers. The memories of physical and selfish (or personal) deeds, on the other hand, together with the mental experiences of a terrestrial nature, and of earthly biological functions, can, of necessity, only be correlated with the molecular constitution of various Kamic organs, and the “dynamical associations” of the elements of the nervous system in each particular organ.
Blessed is he who has acquainted himself with the dual powers at work in the ASTRAL Light; thrice blessed he who has learned to discern the noetic from the Psychic action of the “Double-Faced” God in him, and who knows the potency of his own Spirit — or “Soul Dynamics.”
From “Psychic and Noetic Action”; Lucifer, October-November, 1890