“Q: What distinguishes the “dreaming” memory and imagination from those of waking consciousness?
A: During sleep the physical memory and imagination are of course passive, because the dreamer is asleep, his memory is asleep, all his functions are dormant and at rest. It is only when they are stimulated, as I told you, that they are aroused. Thus the consciousness of the sleeper is not active, but passive.
The inner man, however, the real Ego, acts independently during the sleep of the body; but it is doubtful if any of us – unless thoroughly acquainted with the physiology of occultism – could understand the nature of its action.
Q: What relation have the Astral Light and Akasa to memory?
A: The former is the “tablet of memory” of the animal man, and the latter of the spiritual Ego.
The “dreams” of the Ego, as much as the acts of the physical man, are all recorded, since both are actions based on causes and producing results.
Our “dreams”, being simply the waking state and actions of the true Self, must be, of course, recorded somewhere. Read “Karmic Visions” in Lucifer; and note the description of the real Ego, sitting as a spectator of the life of the hero, and perhaps something will strike you.
Q: What, in reality, is the Astral Light?
A: As the Esoteric Philosophy teaches us, the Astral Light is simply the dregs of Akasa or the Universal Ideation in its metaphysical sense. Though invisible, it is yet, so to speak, the phosphorescent radiation of the latter, and is the medium between it and man’s thought-faculties. It is these which pollute the Astral Light, and make it what it is – the storehouse of all human and especially psychic iniquities.
In its primordial genesis, the astral light as a radiation is quite pure, though the lower it descends approaching our terrestrial sphere, the more it differentiates, and becomes as a result impure in its very constitution. But man helps considerably to this pollution, and gives it back its essence far worse than when he received it.
Q: Can you explain to us how it is related to man, and its action in dream-life?
A: Differentiation in the physical world is infinite. Universal ideation – or Mahat, if you like it – send its homogeneous radiation into the heterogeneous world, and this reaches the human or personal mind through the Astral Light.”
H. P. Blavatsky
The Mark Of God: Understanding Your "I AM Presence" 