The mystery of Mind is undoubtedly the biggest mystery of all, for when he understands that he will have the key which unlocks the door to all the other problems. However, it is necessary to grasp the following: there are two phases of Mind. The first is Consciousness in its everyday form, that is, the consciousness of this time-space-matter world. He has the illusion that this consciousness is a continuous and unified whole, but actually it is like a stream of machine-gun bullets, being made up of an incessant series of disconnected thoughts. Because these thoughts arise and disappear with extraordinary rapidity, the illusion of continuous consciousness, the illusion of an unchangeable, solid world, and the illusion of a separate ego are born. The word "illusion" used here must not be misunderstood. The existence of this amazing trio is not denied for a single moment, because they are there staring him in the face. But this existence is purely relative. It is not absolutely permanent and therefore not real in the Oriental definition of that much-abused word. He must not confine the notion of Mind to that fragment of it which is used in everyday consciousness. What is called Consciousness is merely a portion of what is called Mind, or, functionally regarded, merely one of its faculties. It is the transient and relatively less important portion too. Whether consciousness lives or dies, Mind will always go on because it is the hidden source. Now this Mind in its own pure stage (i.e., unexpressed through everyday human consciousness) is utterly beyond the range of human thinking because it is Absolute, timeless, spaceless, idea-less, and matterless. It has no shape to be seen, no sound to be heard. Consequently from the average human standpoint it is a great Nothing and as a matter of fact some of the Tibetan sages did call it a Great Void. As he cannot pull it down to the grasp of his little human mind and therefore is not ordinarily aware of it, it has sometimes been referred to as the Unconscious Mind, for want of a better term. But such a description is not a good one, as it may lead to dangerous misunderstandings. A better descriptive term must be found. To quote a phrase from one of Disraeli's novels: "The conscious cannot be derived from the unconscious. Man is divine."
It is this Infinite Mind which has been called God, Spirit, Brahman, and so forth. He has to get the knowledge that his own little individual stream of consciousness has flowed out of this great source and will eventually return to it and disappear into it. This is Truth. This universal, impersonal Being is what all are after. The ones who seek it consciously are the people who have taken up the Quest. Those who are after it unconsciously take to drink and other sensual enjoyments and pursue the allurements of this most alluring world.
-- Notebooks Category 21: Mentalism > Chapter 5: The Key To the Spiritual World > # 130