WITH these distinctions clearly in mind, you are in a position to examine in the light of first principles the various theories or conceptions of the subconscious.

In the midst of all the diversity of opinion among scientific men and reputable lay writers, four theories may be said to predominate. Let us briefly summarize these.

1. Some psychologists regard all mental phenomena as nothing more nor less than manifestations of brain activity. This is the point of view of "descriptive psychologists." With them, subconscious activities are but the outward expression of "unconscious cerebration" - that is to say, brain action, brain-cell activities, of which we are unconscious.

Now, with due respect to these distinguished authorities, you, as a student of the mind, must certainly deal with the facts of anesthesia in hysterical persons, the facts of "dissociated personalities," the facts of automatic bodily operations, as expressions of mind activity. They may be immediately caused by brain- or nerve-cell activity. But brain- or nerve-cell activity may in turn have been produced by mind action.

In any event, you are investigating the mind, not the body, and to look upon bodily activities as the result of brain action is to jump from one mode of conceiving things to the other. It is to mix mental and physiological conceptual terms in a manner incompatible with scientific methods.

Nerve fibers cannot be scientifically conceived as forming a connection between two ideas.

You are after practical results.

Your theory of the mind and subconsciousness must explain mental phenomena and enable you to frame mental laws for your future guidance.

Your theory of the subconscious must be based upon purely mental conceptions. It must be constructed wholly out of terms of mind. Only in this way will you be able to so express the laws of mind and apply them in your daily life as to secure the highest degree of efficiency in your mental operations and employ to the fullest extent your mental energies.

2. The term "subconscious" is used by some to define that portion of the field of consciousness which at any moment lies just outside the focus of the attention. By them the subconscious is conceived as an area of restricted attention. To them subconsciousness means merely the marginal horizon or "fringe" of consciousness. And, in this connection, the prefix "sub" implies merely the limited awareness that we have for these facts of consciousness out of the corner of the mind's eye. It is obvious that used in this way the term "subconscious" represents no scientific conception whatever. It is simply a term used to describe certain parts of the field of consciousness, to designate certain facts of experience as but dimly recognized in consciousness as compared with certain other facts.

3. The third use of the term "subconscious" is that in which it is employed chiefly by medical men and students of the psychology of the abnormal. To these men subconscious ideas are ideas which have been dissociated or "split off" from the waking or, as they say, "normal" consciousness, "split off" from the main personal consciousness to such a degree that the owner in his normal state is unaware of their existence.

These dissociated ideas may consist merely of isolated and lost sensations, as in the anesthesia of hysterical patients, or they may be assembled into aggregate and organized groups of sensations. In the latter case they form a consciousness that exists simultaneously with the primary consciousness, and we have the so-called "double" or "multiple" personality.

Now, such a person in his state of primary consciousness has no immediate knowledge of his secondary consciousness, and, vice versa, his secondary consciousness has no immediate knowledge of the existence of the primary consciousness. If either learns of the existence of the other, it is by deduction from appearances or from information which is gathered from other persons.

Meanwhile, the observer, the medical psychologist, deduces the existence of this subconscious state from its outward manifestations, just as he deduces the existence of ordinary consciousness in other persons, not directly, but by inference from their physical manifestations and his own sense-perception of them.

For the student of the mind, then, this secondary consciousness, so far as its essential nature is concerned, is not in any respect different from the ordinary consciousness.

If Professor Janet or Dr. Prince engages in conversation with an individual whose hand, at the same moment and without the knowledge of his primary consciousness, writes answers to the questions of a third person whispered in his ear, then Professor Janet or Dr. Prince will speak of this automatic writing as a manifestation of subconsciousness just as he would speak of the patient's conversation as a manifestation of consciousness.

No attempt is made to reason back of the manifestation and determine how it came about. These men merely recognize the coexistence of the conscious and what they call the subconscious. They do not pretend to offer a scientific conception amounting to an explanation. In the words of Dr. Janet, "it is a simple clinical observation of a common character which these phenomena present."

More than this, the opinion is steadily gaining ground among investigators of this type that the subconscious actually has no part in these manifestations of abnormal mental action. There is a general tendency among them to adopt the suggestion of Dr. Prince and describe such dissociated ideas, organized or disorganized, as "co-conscious," instead of "subconscious."

Now, to limit the term subconscious to abnormal dissociations of ideas of the character we have referred to, falls far short of your requirements. It offers no theory of the mind that you can employ in the practical affairs of your life.

These physicians are concerned only with the manifestations of mental abnormalities and diseased minds. They are not trying to solve the mystery of the healthy normal mind. In the luxuriant garden of the mind they observe only the evidences of decay.

4. The fourth use of the word "subconscious" is an elaboration and expansion of the third. This fourth meaning of the term is that in which it is employed by the great majority of lay writers.

These writers proclaim the existence of two distinct "minds." One of these "minds," the objective, is the mind of sense-impressions, the mind of consciousness, the mind that receives all messages from the outer world and in turn conducts all our immediate activities in relation to it. The other of these "minds" is the subjective. It is entirely outside of consciousness. It has no direct communication with the outer world. We are not directly aware of its existence. It is for each man his individual segment of the Spirit of God.

This last theory, that of the lay writers, is distinctly metaphysical and appeals strongly to the imagination. It is idealistic and fascinating. But it is obvious that the term "subconsciousness" is here taken altogether outside the domain of science and inscribed in the dictionary of religious and speculative philosophy.

Summarizing these different views, we find:

1. That the term "subconscious" is employed by different writers to identify phenomena belonging to entirely different fields of thought.

2. That although these observed facts are strictly mental phenomena, and, so far as you are concerned, should be viewed from the standpoint of the psychologist, many authorities so unfortunately confuse them with physiological material that they seem to make no distinction between mind and brain, and that mind-facts and brain-facts seem to be for them interchangeable terms.

3. That through the writings of lay-men the popular mind has become befuddled with vague and speculative explanations of the facts, explanations that may actually be true, but are in the very nature of things incapable of proof and are utterly out of place in a scientific study of the subject. They are excursions into the dream forest of mysticism, occultism and religion.

4. That of the two theories of the subconscious that may properly be classed as scientific, one defines it as "the fringe of consciousness," the other defines it as a concurrent consciousness, a "co-consciousness," made up of active but dissociated elements of the main or primary consciousness.

You must agree with us that these definitions are narrow and inadequate. You require a scientific conception of the subconscious that shall view the subject in all its phases, shall make broad generalizations possible, and shall thus realize for the mind its full possibilities of usefulness in all the relations of men.

Every one of the theories of the Subconscious that we have outlined falls before one or the other of two objections.

The speculative and metaphysical theory falls before the objection that it is unscientific. The conception of the physicians and the men of scientific repute falls before the objection that it is of limited practical value.

Now, a scientific conception of the subconscious, which shall be at the same time sufficiently broad for general practical use, will not only show you how to cure mental diseases or any other sort of functional diseases, but will also enable you to solve every problem in which mental operations are a factor.

Mental operations are not only a factor, but they are the one and important factor in every phase of a man's career. Consequently you must have a conception of the subconscious that you can use like an algebraic formula in meeting your daily needs, hopes and responsibilities.

The sort of conception of the subconscious that you require must be justifiable from the standpoint of science and must at the same time be sufficiently comprehensive to account for all forms of mental activity outside of consciousness. What you want is a scientific explanation of normal mental processes as well as a scientific explanation of abnormal mental processes.

And, to merit the term "scientific," your conception must conform to the three requirements of every scientific concept: First, it must be expressed in terms that represent the reduction of facts to their essential properties; second, it must be expressed wholly in mental as distinguished from physiological terms, and, third, it must explain all the facts in the sense that no facts can be found to which the explanation could not logically be made to apply.