Kitabı oku: «Your Mind and How to Use It: A Manual of Practical Psychology»

CHAPTER I
What is the Mind?

PSYCHOLOGY is generally considered to be the science of mind, although more properly it is the science of mental states – thoughts, feelings, and acts of volition. It was formerly the custom of writers on the subject of psychology to begin by an attempt to define and describe the nature of mind, before proceeding to a consideration of the subject of the various mental spates and activities. But more recent authorities have rebelled against this demand, and have claimed that it is no more reasonable to hold that psychology should be held to an explanation of the ultimate nature of mind than it is that physical science be held to an explanation of the ultimate nature of matter. The attempt to explain the ultimate nature of either is futile – no actual necessity exists for explanation in either case. Physics may explain the phenomena of matter, and psychology the phenomena of mind, without regard to the ultimate nature of the substance of either.

The science of physics has progressed steadily during the past century, notwithstanding the fact that the theories regarding the ultimate nature of matter have been revolutionized during that period. The facts of the phenomena of matter remain, notwithstanding the change of theory regarding the nature of matter itself. Science demands and holds fast to facts, regarding theories as but working hypotheses at the best. Some one has said that "theories are but the bubbles with which the grown-up children of science amuse themselves." Science holds several well-supported, though opposing, theories regarding the nature of electricity, but the facts of the phenomena of electricity, and the application thereof, are agreed upon by the disputing theorists. And so it is with psychology; the facts regarding mental states are agreed upon, and methods of developing mental powers are effectively employed, without regard to whether mind is a product of the brain, or the brain merely an organ of the mind. The fact that the brain and nervous system are employed in the phenomena of thought is conceded by all, and that is all that is necessary for a basis for the science of psychology.

Disputes regarding the ultimate nature of mind are now generally passed over to the philosophers and metaphysicians, while psychology devotes its entire attention to studying the laws of mental activities, and to discovering methods of mental development. Even philosophy is beginning to tire of the eternal "why" and is devoting its attention to the "how" phase of things. The pragmatic spirit has invaded the field of philosophy, expressing itself in the words of Prof. William James, who said: "Pragmatism is the attitude of looking away from first things, principles, categories, supposed necessities; and of looking forward toward last things, fruits, consequences, facts." Modern psychology is essentially pragmatic in its treatment of the subject of the mind. Leaving to metaphysics the old arguments and disputes regarding the ultimate nature of mind, it bends all its energies upon discovering the laws of mental activities and states, and developing methods whereby the mind may be trained to perform better and more work, to conserve its energies, to concentrate its forces. To modern psychology the mind is something to be used, not merely something about which to speculate and theorize. While the metaphysicians deplore this tendency, the practical people of the world rejoice.

Mind Defined

Mind is defined as "the faculty or power whereby thinking creatures, feel, think, and will." This definition is inadequate and circular in nature, but this is unavoidable, for mind can be defined only in its own terms and only by reference to its own processes. Mind, except in reference to its own activities, cannot be defined or conceived. It is known to itself only through its activities. Mind without mental states is a mere abstraction – a word without a corresponding mental image or concept. Sir William Hamilton expressed the matter as clearly as possible, when he said: "What we mean by mind is simply that which perceives, thinks, feels, wills, and desires." Without the perceiving, thinking, feeling, willing, and desiring, it is impossible to form a clear conception or mental image of mind; deprived of its phenomena it becomes the merest abstraction.

"Think About That Which Thinks."

Perhaps the simplest method of conveying the idea of the existence and nature of the mind is that attributed to a celebrated German teacher of psychology who was wont to begin his course by bidding his students think of something, his desk, for example. Then he would say, "Now think of that which thinks about the desk." Then, after a pause, he would add, "This thing which thinks about the desk, and about which you are now thinking, is the subject matter of our study of psychology." The professor could not have said more had he lectured for a month.

Professor Gordy has well said on this point: "The mind must either be that which thinks, feels, and wills, or it must be the thoughts, feelings, and acts of will of which we are conscious – mental facts, in one word. But what can we know about that which thinks, feels, and wills, and what can we find out about it? Where is it? You will probably say, in the brain. But, if you are speaking literally, if you say that it is in the brain, as a pencil is in the pocket, then you must mean that it takes up room, that it occupies space, and that would make it very much like a material thing. In truth, the more carefully you consider it, the more plainly you will see what thinking men have known for a long time – that we do not know and cannot learn anything about the thing which thinks, and feels, and wills. It is beyond the range of human knowledge. The books which define psychology as the science of mind have not a word to say about that which thinks, and feels, and wills. They are entirely taken up with these thoughts and feelings and acts of the will, – mental facts, in a word, – trying to tell us what they are, and to arrange them in classes, and tell us the circumstances or conditions under which they exist. It seems to me that it would be better to define psychology as the science of the experiences, phenomena, or facts of the mind, soul, or self – of mental facts, in a word."

In view of the facts of the case, and following the example of the best of the modern authorities, in this book we shall leave the consideration of the question of the ultimate nature of mind to the metaphysicians, and shall confine ourselves to the mental facts, the laws governing them, and the best methods of governing and using them in "the business of life."

The classification and method of development to be followed in this book is as follows: —

I. The mechanism of mental states, i. e., the brain, nervous system, sense organs, etc.

II. The fact of Consciousness and its planes.

III. Mental processes or faculties, i. e., (1) Sensation and Perception; (2) Representation, or Imagination and Memory; (3) Feeling or Emotion; (4) Intellect, or Reason and Understanding; (5) Will or Volition.

Mental states depend upon the physical mechanism for manifestation, whatever may be the ultimate nature of mind. Mental states, whatever their special character, will be found to fit into one of the above five general classes of mental activities.

CHAPTER II
The Mechanism of Mental States

THE mechanism of mental states – the mental machinery by means of which we feel, think, and will – consists of the brain, nervous system, and the organs of sense. No matter what may be the real nature of mind, – no matter what may be the theory held regarding its activities, – it must be admitted that the mind is dependent upon this mechanism for the manifestation of what we know as mental states. Wonderful as is the mind, it is seen to be dependent upon this physical mechanism for the expression of its activities. And this dependence is not upon the brain alone, but also upon the entire nervous system.

The best authorities agree that the higher and more complex mental states are but an evolution of simple sensation, and that they are dependent upon sensation for their raw material of feeling and thought. Therefore it is proper that we begin by a consideration of the machinery of sensation. This necessitates a previous consideration of the nerves.

The Nerves

The body is traversed by an intricate system of nerves, which has been likened to a great telegraph system. The nerves transmit sensations from the various parts of the body to the great receiving office of the brain. They also serve to transmit the motor impulses from the brain to the various parts of the body, which impulses result in motion of appropriate parts of the body. There are also other nerves with which we have no concern in this book, but which perform certain physiological functions, such as digestion, secretion, excretion, and circulation. Our chief concern, at this point, is with the sensory nerves.

The sensory nerves convey the impressions of the outside world to the brain. The brain is the great central station of the sensory nerves, the latter having countless sending stations in all parts of the body, the "wires" terminating in the skin. When these nervous terminal stations are irritated or excited, they send to the brain messages calling for attention. This is true not only of the nerves of touch or feeling, but also of those concerned with the respective senses of sight, smell, taste, and hearing. In fact, the best authorities hold that all the five senses are but an evolution of the primary sense of touch or feeling.

The Sense of Touch

The nerves of the sense of touch have their ending in the outer covering or skin of the body. They report contact with other physical objects. By means of these reports we are aware not only of contact with the outside object, but also of many facts concerning the nature of that object, as for instance, its degree of hardness, roughness, etc., and its temperature. Some of these nerve ends are very sensitive, as, for example, those of the tip of the tongue and finger ends, while others are comparatively lacking in sensitiveness, as, for illustration, those of the back. Certain of these sensory nerves confine themselves to reporting contact and degrees of pressure, while others concern themselves solely with reporting the degrees of temperature of the objects with which their ends come in contact. Some of the latter respond to the higher degrees of heat, while others respond only to the lower degrees of cold. The nerves of certain parts of the body respond more readily and distinctly to temperature than do those of other parts. To illustrate, the nerves of the cheek are quite responsive to heat impressions.

The Sense of Sight

The nerves of the sense of sight terminate in the complex optical apparatus which in popular terminology is known as "the eye." What is known as "the retina" is a very sensitive nervous membrane which lines the inner, back part of the eye, and in which the fibers of the optic nerve terminate. The optical instrument of the eye conveys the focused light vibrations to the nerves of the retina, from which the impulse is transmitted to the brain. But, contrary to the popular notion, the nerves of the eye do not gauge distances, nor form inferences of any kind; that is distinctly the work of the mind. The simple office of the optical nerves consists in reporting color and degrees of intensity of the light waves.

The Sense of Hearing

The nerves of the sense of hearing terminate in the inner part of the ear. The tympanum, or "ear drum," receives the sound vibrations entering the cavities of the ear, and, intensifying and adapting them, it passes them on to the ends of the auditory nerve in the internal ear, which conveys the sensation to the brain. The auditory nerve reports to the brain the degrees of pitch, intensity, quality, and harmony, respectively, of the sound waves reaching the tympanum. As is well known, there are certain vibrations of sound which are too low for the auditory nerve to register, and others too high for it to record, both classes, however, capable of being recorded by scientific instruments. It is also regarded as certain that some of the lower animals are conscious of sound vibrations which are not registered by the human auditory nerves.

The Sense of Smell

The nerves of the sense of smell terminate in the mucous membrane of the nostrils. In order that these nerves report the odor of outside objects, actual contact of minute particles of the object with the mucous membrane of the nostrils is necessary. This is possible only by the passage through the nostrils of air containing these particles; mere nearness to the nostril will not suffice. These particles are for the most part composed of tenuous gases. Certain substances affect the olfactory nerves much more than do others, the difference arising from the chemical composition of the substance. The olfactory nerves convey the report to the brain.

The Sense of Taste

The nerves of the sense of taste terminate in the tongue, or rather in the tiny cells of the tongue which are called "taste buds." Substances taken into the mouth chemically affect these tiny cells, and an impulse is transmitted to the gustatory nerves, which then report the sensation to the brain. The authorities claim that taste sensations may be reduced to five general classes, viz.: sweet, bitter, sour, salty, and "hot."

There are certain nerve centers having important offices in the production and expression of mental states, located in the skull and in the spinal column – the brain and the spinal cord – which we shall consider in the following chapter.

CHAPTER III
The Great Nerve Centers

THE great nerve centers which play an important part in the production and expression of mental states are those of the brain and spinal cord, respectively.

The Spinal Cord

The spinal cord is that cord or rope of nerve substance which is inclosed in the spinal column or "backbone." It leaves the lower part of the skull and extends downward in the interior of the spinal column for about eighteen inches. It is continuous with the brain, however, and it is difficult to determine where one begins and the other ends. It is composed of a mass of gray matter surrounded by a covering of white matter. From the spinal cord, along its length, emerge thirty-one pairs of spinal nerves which branch out to each side of the body and connect with the various smaller nerves, extending to all parts of the system. The spinal cord is the great central cable of the nervous telegraphic system, and any injury to or obstruction of it cripples or paralyzes those portions of the body the nerves of which enter the spinal cord below the seat of the injury or obstruction. Injuries or obstructions of this kind not only inhibit the sensory reports from the affected area, but also inhibit the motor impulses from the brain which are intended to move the limbs or parts of the body.

The Ganglia or "Tiny Brains."

What are known as ganglia, or tiny bunches of nerve cells, are found in various parts of the nervous system, including the spinal nerves. These groups of nerve cells are sometimes called "little brains," and perform quite important offices in the mechanism of thought and action. The spinal ganglia receive sensory reports, and issue motor impulses, in many cases, without troubling the central brain regarding the matter. These activities are known as "reflex nervous action."

Reflex Action

What is known as reflex nervous action is one of the most wonderful of the activities of the nervous and mental mechanism, and the knowledge thereof usually comes as a surprise to the average person, for he is generally under the impression that these activities are possible only to the central brain. It is a fact that not only is the central brain really a trinity of three brains, but that, in addition to these, every one has a great number of "little brains" distributed over his nervous system, any and all of which are capable of receiving sensory reports and also of sending forth motor impulses. It is quite worth while for one to become acquainted with this wonderful form of neuro-mental activity.

A cinder enters the eye, the report reaches a ganglion, a motor impulse is sent forth, and the eyelid closes. The same result ensues if an object approaches the eye but without actually entering it. In either case the person is not conscious of the sensation and motor impulse until the latter has been accomplished. This is reflex action. The instinctive movement of the tickled foot is another instance. The jerking away of the hand burnt by the lighted end of the cigar, or pricked by the point of the pin, is another instance. The involuntary activities, and those known as unconscious activities, result from reflex action.

More than this, it is a fact that many activities originally voluntary become what is known as "acquired reflexes," or "motor habits," by means of certain nervous centers acquiring the habit of sending forth certain motor impulses in response to certain sensory reports. The familiar movements of our lives are largely performed in this way, as, for instance, walking, using knife and fork, operating typewriters, machines of all kinds, writing, etc. The squirming of a decapitated snake, the muscular movements of a decapitated frog, and the violent struggles, fluttering, and leaps of the decapitated fowl, are instances of reflex action. Medical reports indicate that in cases of decapitation even man may manifest similar reflex action in some cases. Thus we may see that we may feel and will by means of our "little brains" as well as by the central brain or brains. Whatever mind may be, it is certain that in these processes it employs other portions of the nervous system than the central brain.

The Three Brains

What is known as the brain of man is really a trinity of three brains, known respectively as (1) the medulla oblongata, (2) the cerebellum, and (3) the cerebrum. If one wishes to limit the mental activity to conscious intellectual effort, then and then only is he correct in considering the cerebrum or large brain as "the brain."

The Medulla Oblongata.– The medulla oblongata is an enlargement of the spinal cord at the base of the brain. Its office is that of controlling the involuntary activities of the body, such as respiration, circulation, assimilation, etc. In a broad sense, its activities may be said to be of the nature of highly developed and complex reflex activities. It manifests chiefly through the sympathetic nervous system which controls the vital functions. It does not need to call on the large brain in these matters, ordinarily, and is able to perform its tasks without the plane of ordinary consciousness.

The Cerebellum.– The cerebellum, also known as "the little brain," lies just above the medulla oblongata, and just below the rear portion of the cerebrum or great brain. It combines the nature of a purely reflex center on the one hand, with that of "habit mind" on the other. In short, it fills a place between the activities of the cerebrum and the medulla oblongata, having some of the characteristics of each. It is the organ of a number of important acquired reflexes, such as walking, and many other familiar muscular movements, which have first been consciously acquired and then become habitual. The skilled skater, bicyclist, typist, or machinist depends upon the cerebellum for the ease and certainty with which he performs his movements "without thinking of them." One may be said never to have thoroughly acquired a set of muscular movements such as we have mentioned, until the cerebellum has taken over the task and relieved the cerebrum of the conscious effort. One's technique is never perfected until the cerebellum assumes control and direction of the necessary movements and the impulses are sent forth from below the plane of ordinary consciousness.

The Cerebrum.– The cerebrum, or "great brain" (which is regarded as "the brain" by the average person), is situated in the upper portion of the skull, and occupies by far the larger portion of the cavity of the skull. It is divided into two great divisions or hemispheres. The best of the modern authorities are agreed that the cerebrum has zones or areas of specialized functioning, some of which receive the sensory reports of the nerves and organs of sense, while others send forth the motor impulses which result in voluntary physical action. Many of these areas or zones have been located by science, while others remain as yet unlocated. The probability is that in time science will succeed in correctly locating the area or zone of each and every class of sensation and motor impulse.

The Cortex

The area of thought, memory, and imagination has not been clearly located, except that these mental states are believed to have their seat in the cortex or outer thin rind of gray brain matter which envelopes and covers the mass of brain substance. It is, moreover, considered probable that the higher processes of reasoning are performed in or by the cortex of the frontal lobes. The cortex of a person of average intelligence, if spread out on a flat surface, measures about four square feet. The higher the degree of intelligence possessed by a lower animal or human being, as a rule, the deeper and more numerous are the folds or convolutions of the cortex, and the finer its structure. It may be stated as a general rule, with but very few exceptions, that the higher the degree of intelligence in a lower animal or human being, the greater is the area of its cortex in proportion to the size of the brain. The cortex, it must be remembered, is folded into deep furrows or convolutions, the brain in shape, divisions, and convolutions resembling the inner portion of an English walnut. The interior of the two hemispheres of the cerebrum is composed largely of connective nerves which doubtless serve to produce and maintain the unity of function of the mental processes.

While physiological psychology has performed great work in discovering brain-centers and explaining much of the mechanism of mental processes, it has but touched the most elementary and simple of the mental processes. The higher processes have so far defied analysis or explanation in the terms of physiology.