IT WOULD be idle for us to work with elements that we do not understand. What, then, is attention, and how does it operate?

We have referred to attention as a "selective agency," a "discriminatory process," "a watchful sentinel alert to guard consciousness from all sensory stimuli (past or present), not bearing the countersign of relevancy." In other words, you know what attention does; but the question is, How does it do it? What is the mechanism by which attention can cause one sense-perception, one idea, the one attended to, to stand out in clear perspective, while all other sense-perceptions and ideas, or, more accurately, all conflicting sense-impressions and ideas, are ignored?

It is a fundamental fact recognized by psychologists that every idea carries with it the impulse to a bodily movement. Every idea possesses an innate impellent energy.

The mind has been likened to a great switchboard, transforming incoming messages into outgoing ones - sensory stimuli into muscular reactions. The picture is not strictly accurate. The incoming message awakens an impulse to muscular reaction, but whether the reaction shall actually occur or not depends upon other conditions and circumstances.

Yet the fact that every idea is associated with even the impulse to bodily activity, whether the impulse be carried out or not, should, and in fact does, make it possible for us to acquire an understanding of the mental process of attention from a study of the bodily mechanism with which it is so closely involved.

There are countless millions of nerve fibers leading from the surface of the body to the brain. It is along these fibers that messages from the outer world are transmitted to the central intelligence. But in addition to these inbound nerves, there are untold millions of other nerve fibers carrying outbound "currents" to various special centers which directly govern muscular action.

Every impression that you receive from without is therefore something more than merely the result of an incoming current. It is also the starting-point for an outgoing one. Every sense-impression, every idea, carries with it the impulse to some form of bodily action.

Look out of the window. Every separate ray of light falling upon the retina of your eye, and by it transmitted to some brain cell, creates an impulse to move the eye in that direction. Your eye may not move, for the impulse to turn the eye in a number of contrary directions may all be equally strong.

They may balance and offset one another. And in that event your eye must remain stationary.

On the other hand suppose the impulses from incoming sense-impressions are unequal. The great preponderance of their influence may tend to direct your eye toward a particular spot of vivid color. And yet your eye may not move in that direction. For there may be simultaneously present in your consciousness something besides sense-impressions. There may be an idea with an impellent energy of its own, an idea the innate interest of which demands that the eye shall remain focused upon one supremely interesting spot. Yet all the time those thousands of contrary impulses are working for release, and the position of your eye at any moment is wholly a matter of mental equilibrium.

Every move you make, every step you take, every item of your outward behavior, the whole sum of your activities in this world, all are the net result of opposing forces.

A multitude of energies are continually at work, struggling to produce certain muscular movements and to restrain antagonistic ones. The complexity of these relations is almost inconceivable.

Nor are you to suppose for a moment that you are aware of all the muscular movements that thus actually come about. Many of these energies find an outlet through the motor nerves and you know neither when nor how. Remember that a smile, a frown, a groan, a sigh, are all just as much the effect of mental impulses as is the act of walking. "A king's breath slays as effectively as an assassin's blow."

Knowing this much of the mechanism of the nervous system of the body, you can now understand how attention does its work.

1. All ideas are but past sense-impressions classified, grouped and catalogued in subconsciousness.

2. Every idea is indissolubly bound up with its appropriate and associated motor impulse.

3. Whenever any idea becomes active in consciousness, its associated impellent energy tends simultaneously to manifest itself in muscular action. No external action may follow because of the activity at the same time in consciousness of other ideas with impulses to muscular action antagonistic to the first. The stream of the first impulse may be dammed up by contrary impulses, but it is nevertheless there and exerting all its pressure toward release. 4. Thousands of mental images linked with thousands of emotions and impulses must continually arise in your consciousness, but only those have a chance for complete and vivid development that are in harmony with your previous mental disposition. These are the only ones whose impulses are allowed to manifest themselves in outward activity.

5. This mental disposition is determined by your present trend of interest and by your purposive will. Your general interest, your aim in life, determines just what sensory experiences and what ideas shall be selected at any given moment from the vast stream of incoming sense-impressions and up-thronging ideas and shall be allowed to find free expression in outward bodily action.

For example, a composer is engaged in the construction of an opera. In fancy the whole scene is before him. The principals and chorus are in their places. He sees every singer. He has the whole plot in mind. He hears and singles out each one of the multitude of individual tones from the orchestra.

He marks the effect of each individual instrument upon the composite harmony. Suppose that while he is thus absorbed in a creative vision his servant steps to the door and in an ordinary-tone of voice informs him that dinner is served. The words will very likely go unheard. The servant's message is not in accord with the master's mental disposition. The master's ear receives the empty sound of what the servant says, but it is barred from consciousness. It awakens no perception. And its impulse to appropriate bodily action has no effect, because the master's consciousness is busy with other and different things.

6. To fix your attention means to arrange a mental setting or disposition in which the spot-light of your consciousness is reserved for matters related to the subject of attention.

If you fix your attention upon a picture, you examine into its details. In other words, in fixing your attention upon the picture you so arrange the contents of your consciousness as to bring about the bodily action that will increase your knowledge of the picture. Thus, you keep the eye steadfastly turned in that direction. You see every detail in magnified form, and, more important still, antagonistic conscious activities are inhibited so that your mind and judgment are left free for the consideration of the one subject. Thus, attention and fixation of attention is an arrangement of mental forces so that some impulses to action are re-enforced and others are inhibited.

Stop now and mark the significance of all this. You accepted the idea that mental control would mean functional health, material success and happiness, self-realization in the fullest sense. Observe now the basic principle of mind mastery: The mind and all individual human energies are amenable to control by concentration of the attention.