(b) In the average man, the mental body is much increased in size, shows a certain amount of organization, and contains a fair proportion of matter drawn from the second, third and fourth subdivisions of the mental plane.
The general law which regulates all the building up and modifying of the mental body may here be fitly studied, though it is the same principle already seen working in the lower realms of the astral and physical worlds. Exercise increases, disuse atrophies and finally destroys. Every vibration set up in the mental body causes a change in its constituents, throwing out of it, in the part affected, the matter that cannot vibrate sympathetically, and replacing it by suitable materials drawn from the practically illimitable store around.
The more a series of vibrations is repeated, the more does the part affected by them increase in development; hence, it may be noted in passing, the injury done to the mental body by over-specialization of mental energies. Such mistaken direction of these powers causes a lop-sided development of the mental body; it becomes proportionately over-developed in the region in which these forces are continually playing and proportionately undeveloped in other parts, perhaps equally important. A harmonious and proportionate all-round development is the object to be sought, and for this are needed a calm self-analysis and a definite direction of means to ends.
A knowledge of this law further explains certain familiar experiences, and affords a sure hope of progress. When a new study is commenced, or a change in favour of high morality is initiated, the early stages are found to be fraught with difficulties; sometimes even the effort is abandoned because the obstacles in the way of its success appear to be insurmountable. At the beginning of any new mental undertaking, the whole automatism of the mental body opposes it; the materials, habituated to vibrate in a particular way, cannot accommodate themselves to the new impulses, and the early stage consists chiefly of sending out thrills of force which are frustrated, so far as setting up vibrations in the mental body are concerned, but which are the necessary preliminary to any such sympathetic vibrations, as they shake out of the body the old refractory materials and draw into it the sympathetic kinds. During this process, the man is not conscious of any progress; he is only conscious of the frustration of his efforts, and of the dull resistance he encounters.
Presently, if he persists, as the newly attracted materials begin to function, he succeeds better in his attempts; and at last, when all the old materials are expelled and the new are working, he finds himself succeeding without any effort, and his object is accomplished. The critical time is during the first stage, but if he trust in the law—as sure in its working as every other law in Nature—and persistently repeat his efforts, he must succeed; and a knowledge of this fact may cheer him when otherwise he would be sinking in despair.
In this way, then, the average man may work on, finding with joy that as he steadily resists the promptings of the lower nature, he is conscious they are losing their power over him, for he is expelling from his mental body all the materials that are capable of being thrown by them into sympathetic vibrations. Thus the mental body gradually comes to be composed of the finer constituents of the four lower subdivisions of the mental plane, until it has become the radiant and exquisitely beautiful form which is the mental body of the (c) Spiritually developed man.
From this body all the coarser combinations have been eliminated, so that the objects of the senses no longer find in it, or in the astral body connected with it, materials that respond sympathetically to their vibrations. It contains only the finer combinations belonging to each of the four sub-divisions of the lower mental world, and of these again, the materials of the third and fourth subplanes very much predominate in its composition over the materials of the second and first, making it responsive to all the higher workings of the intellect, to the delicate contacts to the higher arts, lo all the pure thrills of the loftier emotions.
Such a body enables the Thinker who is clothed in it to express himself much more fully in the lower mental region and in the astral and physical worlds; its materials are capable of a far wider range of responsive vibrations, and the impulses from a loftier realm mould it into nobler and subtler organization. Such a body is rapidly becoming ready to reproduce every impulse from the Thinker which is capable of expression on the lower sub-divisions of the mental plane; it is growing into a perfect instrument for activities in this lower mental world.
***From Annie Besant – The Ancient Wisdom