Let us now consider, in this light, the relations between the higher and lower mind and their action on the brain. The mind, Manas, the Thinker is one, and is the Self in the causal body; it is the source of innumerable energies, of vibrations of innumerable kinds. These it sends out, raying outwards from itself.
The subtlest and finest of these are expressed in the matter of the causal body, which alone is fine enough to respond to them; they form what we call the Pure Reason, whose thoughts are abstract, whose method of gaining knowledge is intuition; its very nature is “knowledge,” and it recognizes truth at sight as congruous with itself. Less subtle vibrations pass outwards, attracting the matter of the lower mental region, and these are the Lower Manas, or lower mind—the coarser energies of the higher expressed in denser matter; these we call the intellect, comprising reason, judgment, imagination, comparison, and the other mental faculties; its thoughts are concrete, and its method is logic; it argues, it reasons, it infers.
These vibrations, acting through astral matter on the etheric brain, and by that on the dense physical brain, set up vibrations therein, which are the heavy and slow reproductions of themselves—heavy and slow, because the energies lose much of their swiftness in moving the heavier matter. This feebleness of response when a vibration is initiated in a rare medium and then passes into a dense one is familiar to every student of physics. Strike a bell in air and it sounds clearly; strike it in hydrogen, and let the hydrogen vibrations set up the atmospheric waves, and how faint the result. Equally feeble are the workings of the brain in response to the swift and subtle impacts of the mind ; yet that is all that the vast majority know as their “consciousness.”
The immense importance of the mental workings of this “consciousness” is due to the fact that it is the only medium whereby the Thinker can gather the harvest of experience by which he grows. While it is dominated by the passions it runs riot, and he is left unnourished and therefore unable to develop; while it is occupied wholly in mental activities concerned with the outer world, it can arouse only his lower energies; only as he is able to impress on it the true object of its life, does it commence to fulfill its most valuable functions of gathering what will arouse and nourish his higher energies.
As the Thinker develops he becomes more and more conscious of his own inherent powers, and also of the workings of his energies on the lower planes, of the bodies which those energies have drawn around him. He at last begins to try to influence them, using his memory of the past to guide his will, and these impressions we call “conscience” when they deal with morals, and “ flashes of intuition ” when they enlighten the intellect. When these impressions are continuous enough to be normal, we speak of their aggregate as “ genius.”
The higher evolution of the Thinker is marked by his increasing control over his lower vehicles, by their increasing susceptibility to his influence, and their increasing contributions to his growth. Those who would deliberately aid in this evolution may do so by a careful training of the lower mind and of the moral character, by steady and well-directed effort. The habit of quiet, sustained and sequential thought, directed to non-worldly subjects, of meditation, of study, develops the mind-body and renders it a better instrument ; the effort to cultivate abstract thinking is also useful, as this raises the lower mind towards the higher, and draws into it the subtlest materials of the lower mental plane.
Hate ways all may actively co-operate in their own higher evolution, each step forward making the succeeding steps more rapid. No effort, not even the smallest, is lost, but is followed by its full effect, and every contribution gathered and handed inwards is stored in the treasure-house of the causal body for future use.
Thus evolution, however slow and halting, is yet ever onwards, and the divine Life, ever-unfolding in every soul, slowly subdues all things to itself.
***From Annie Besant – The Ancient Wisdom