M.D., PH.D., LITT.D., LL.D. PROFESSOR OF PSYCHOLOGY IN HARVARD UNIVERSITY
NEW YORK MOFFAT, YARD AND COMPANY 1909
COPYRIGHT, 1909, BY MOFFAT, YARD AND COMPANY
All Rights Reserved
Published, April, 1909 Second Printing, May, 1909
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RECENT BOOKS BY THE SAME AUTHOR
Psychology and Life, Boston, 1899
Grundzuege der Psychologie, Leipzig, 1900
American Traits, Boston, 1902
Die Amerikaner, Berlin, 1904
Principles of Art Education, New York, 1905
The Eternal Life, Boston, 1905
Science and Idealism, Boston, 1906
Philosophie der Werte, Leipzig, 1907
On the Witness Stand, New York, 1908
Aus Deutsch-Amerika, Berlin, 1908
The Eternal Values, Boston, 1909
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MY FRIEND AND COLLEAGUE
DR. FRANZ PFAFF
PROFESSOR OF THERAPEUTICS IN HARVARD UNIVERSITY
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This volume on psychotherapy belongs to a series of books which I am writing to discuss for a wider public the practical applications of modern psychology. The first book, called "On the Witness Stand," studied the relations of scientific psychology to crime and the law courts. This new book deals with the relations of psychology to medicine. Others discussing its relations to education, to social problems, to commerce and industry will follow soon.
For popular treatment I divide applied psychology into such various, separated books because they naturally address very different audiences. That which interests the lawyer does not concern the physician, and again the school-teacher has his own sphere of interests. Moreover the different subjects demand a different treatment. The problems of psychology and law were almost entirely neglected. I was anxious to draw wide attention to this promising field and therefore I chose the form of loose popular essays without any aim towards systematic presentation of the subject. As to psychology and medicine almost the opposite situation prevails. There is perhaps too much talk afloat about psychotherapy, the widest circles cultivate the discussion, the magazines overflow with it. The duty of the scientific psychologist is accordingly not to stir up interest in this topic but to help in bringing this interest from mere gossip, vague mysticism, and medical amateurishness to a clear understanding of principles. What is needed in this time of faith cures of a hundred types is to deal with the whole circle of problems in a serious, systematic way and to emphasize the aspect of scientific psychological theory.
Hence the whole first part of this book is an abstract discussion and its first chapters have not even any direct relation to disease. I am convinced that both physicians and ministers and all who are in practical contact with these important questions ought to be brought to such painstaking and perhaps fatiguing inquiry into principles before the facts are reached. To those who seek a discussion of life facts alone, the whole first part will of course appear to be a tedious way around; they may turn directly to the second and third parts.
One word for my personal right to deal with these questions, as too much illegitimate psychotherapeutics is heard to-day. For me, the relation between psychology and medicine is not a chance chapter of my science to which I have turned simply in following up the various sides of applied psychology. And still less have I turned to it because it has become the fashion in recent years. On the contrary, it has been an important factor in all my work since my student days. I have been through five years of regular medical studies, three years in Leipzig and two years in Heidelberg; I have an M.D. degree from the University of Heidelberg. In my first year as docent in a German university twenty years ago, I gave throughout the winter semester before several hundred students a course in hypnotism and its medical application. It was probably the first university course on hypnotism given anywhere. Since that time I have never ceased to work psychotherapeutically in the psychological laboratory. Yet that must not be misunderstood. I have no clinic, and while by principle I have never hypnotized anyone for mere experiment's sake but always only for medical purposes, yet I adjust my practical work entirely to the interests of my scientific study. The limitations of my time force me to refuse the psychotherapeutic treatment of any case which has not a certain scientific interest for me, and of the many hundreds whom I have helped in the laboratory, no one ever had to pay anything. Thus my practical work has strictly the character of laboratory research.
The chief aim of this book is twofold. It is a negative one: I want to counteract the misunderstandings which overflood the whole field, especially by the careless mixing of mental and moral influence. And a positive one: I want to strengthen the public feeling that the time has come when every physician should systematically study psychology, the normal in the college years and the abnormal in the medical school. This demand of medical education cannot be postponed any longer. The aim of the book is not to fight the Emmanuel Church Movement, or even Christian Science or any other psychotherapeutic tendency outside of the field of scientific medicine. I see the element of truth in all of them, but they ought to be symptoms of transition. Scientific medicine should take hold of psychotherapeutics now or a most deplorable disorganization will set in, the symptoms of which no one ought to overlook to-day.
HARVARD UNIVERSITY, March 20, 1909.
I. INTRODUCTION 1
THE PSYCHOLOGICAL BASIS OF PSYCHOTHERAPY
II. THE AIM OF PSYCHOLOGY 9
III. MIND AND BRAIN 27
IV. PSYCHOLOGY AND MEDICINE 55
V. SUGGESTION AND HYPNOTISM 85
VI. THE PSYCHOLOGY OF THE SUBCONSCIOUS 125
THE PRACTICAL WORK OF PSYCHOTHERAPY
VII. THE FIELD OF PSYCHOTHERAPY 158
VIII. THE GENERAL METHODS OF PSYCHOTHERAPY 184
IX. THE SPECIAL METHODS OF PSYCHOTHERAPY 212
X. THE MENTAL SYMPTOMS 239
XI. THE BODILY SYMPTOMS 297
THE PLACE OF PSYCHOTHERAPY
XII. PSYCHOTHERAPY AND THE CHURCH 319
XIII. PSYCHOTHERAPY AND THE PHYSICIAN 347
XIV. PSYCHOTHERAPY AND THE COMMUNITY 370
Psychotherapy is the practice of treating the sick by influencing the mental life. It stands at the side of physicotherapy, which attempts to cure the sick by influencing the body, perhaps with drugs and medicines, or with electricity or baths or diet.
Psychotherapy is sharply to be separated from psychiatry, the treatment of mental diseases. Of course to a certain degree, mental illness too, is open to mental treatment; but certainly many diseases of the mind lie entirely beyond the reach of psychotherapy, and on the other hand psychotherapy may be applied also to diseases which are not mental at all. That which binds all psychotherapeutic efforts together into unity is the method of treatment. The psychotherapist must always somehow set levers of the mind in motion and work through them towards the removal of the sufferer's ailment; but the disturbances to be treated may show the greatest possible variety and may belong to mind or body.
Treatment of diseases by influence on the mind is as old as human history, but it has attained at various times very different degrees of importance. There is no lack of evidence that we have entered into a period in which an especial emphasis will be laid on the too long neglected psychical factor. This new movement is probably only in its beginning and the loudness with which it presents itself to-day is one of the many indications of its immaturity. Whether it will be a blessing or a danger, whether it will really lead forward in a lasting way, or whether it will soon demand a reaction, will probably depend in the first place on the soberness and thoroughness of the discussion. If the movement is carried on under the control of science, it may yield lasting results. If it keeps the features of dilettanteism and prefers association with the antiscientific tendencies, it is pre-destined to have a spasmodic character and ultimately to be harmful.
The chaotic character of psychotherapy in this first decade of the twentieth century can be easily understood. It results from the fact that in our period one great wave of civilization is sinking and a new wave rising, while the one has not entirely disappeared and the other is still far from its height. The history of civilization has shown at all times a wavelike alternation between realism and idealism, that is, between an interest in that which is, and an interest in that which ought to be. In the realistic periods, the study of facts, especially of the facts of nature, is prevalent; in idealistic periods, history and literature appeal to the world. In realistic periods, technique enjoys its triumphs; in idealistic periods, art and religion prevail. Such a realistic movement lies behind us. It began with the incomparable development of physics, chemistry, and biology, in the middle of the last century, and it brought with it the achievements of modern engineering and medicine. We are still fully under the influence of this gigantic movement and its real achievements will never leave us; and yet this realistic wave is ebbing to-day and a new period of idealism is rising. If the signs are not deceitful, this new movement may reach its historical climax a few decades hence, when new leaders may give to the idealistic view of the world the same classical expression which Darwin and others gave to the receding naturalistic age. The signs are clear indeed that the days of idealistic philosophy and of art, and of religion, are approaching; that the world is tired of merely connecting facts without asking what their ultimate meaning is. The world dimly feels again that technical civilization alone cannot make life more worth living. The aim of the last generation was to explain the world; the aim of the next generation will be to interpret the world; the one was seeking laws, the other will seek ideals.
Psychotherapy stands in the service of both; it is the last word of the passing naturalistic movement, and yet in another way it tries to be the first word of the coming idealistic movement; and because it is under the influence of both, it speaks sometimes the language of the one, and sometimes the language of the other. That brings about a confusion and a disorder which must be detrimental. To transform this vagueness into clear, distinct relations is the immediate duty of science.
Indeed it may be said that psychotherapy is the last word of a naturalistic age, because psychotherapy finds its real stronghold in a systematic study of the mental laws, and such study of mental laws, psychology, must indeed be the ultimate outcome of a naturalistic view of the world. Realism begins with the analysis of lifeless nature, begins with the study of the stars and the stones, of masses and of atoms. At a higher level, it turns then to the living organism, studies plants and animals and even brings the human organism entirely under the point of view of natural law. When science has thus mastered the whole physical universe, it finally brings even the mental life of man under the naturalistic point of view, treats his inner experiences like any outer objects, tears them in pieces, analyzes them, and studies them as functions of the nervous system. A scientific psychology is thus reached which is the climax of realism, because it means that even the ideas and emotions and volitions of man are treated as natural phenomena, that their causes are sought and that their effects are determined, that their laws are found out. To apply this realistic knowledge of the mind in the interest of therapy is merely to use it in the same way in which the engineer uses his knowledge of physics, when he wants to harness outer nature. As that is possible only when theoretical science has reached a certain height of development, it can indeed be said that practical psychotherapy on a scientific basis can be considered almost as the ultimate point of a realistic movement; it cannot set in until psychology has reached high development, and psychology cannot set in unless biology has preceded it.
There is no doubt that we are still far from this last phase of the realistic period. The practical application of scientific psychology is still a new problem. Experimental psychology began about twenty-five years ago; at that time there existed one psychological laboratory. To-day there is no university in the world which does not have a psychological workshop. But laboratories for applied psychology are only arising in these present days, and the systematic application of scientific psychology to education and law and industry and social life and medicine is almost at its beginning. While the height of the last realistic wave was in the period of the sixties, seventies, and eighties, of the last century, its last phase, the practical application of physiological psychology, including psychotherapy, is only at its commencement.
But while this last great movement has not yet reached its end, the new idealistic movement to come has not yet reached a clear self-expression. A general philosophical interest can be felt, but a great philosophical synthesis seems still lacking. A new sense of duty can vaguely be felt, but great new tasks have not yet found common acknowledgment. Above all, the unshaped emotionalism of the masses has not yet been brought into any real contact with the new idealism which grows up on the higher level of scholarly thought. But it is evident, if a new great mood of idealism is to come, one of its popular forerunners must be the demand that the spirit is real in a higher sense than matter, that the mind controls the body, that faith can cure. In such unphilosophic crudeness, no definite thought is expressed, as everything would depend on the definition of spirit, of faith, of mind, of reality. Moreover, every inquiry would prove that the idealistic value of such statements as are afloat among the masses to-day is reached only by a juggling with words. That faith can cure appears to point towards the higher world, as the word faith has there the connotation of the faith in a religious sense; and yet the faith which really cures a digestive trouble, for instance, is the faith in the final overcoming of the intestinal disturbance, an idea which belongs evidently in the region of physiological psychology, but not in the region of the church. Yet, however clumsy such statements may be, they are surely controlled by the instinctive desire for a new idealistic order of our life, and the time will come when their unreasoning and unreasonable wisdom will be transformed into sound philosophy without losing its deepest impulse. The realistic conviction that even the mind is completely controlled by natural laws and the idealistic inspiration that the mind of man has in its freedom mastery over the body, are thus most curiously mixed in the popular psychotherapy of the day, and too few recognize that the real meaning of mind is an entirely different one in these two propositions.
Of course the one or the other of these two elements prevails in the systematic treatises on the subject; the realistic one in those written by the psychiatrists, the idealistic one in those written by clergymen or Christian Scientists. The literature indeed is almost entirely supplied from these two quarters: and yet it is evident that neither the one nor the other party can give to the problem its most natural setting. The student of mental diseases naturally emphasizes the abnormal features of the situation, and thus brings the psychotherapeutic process too much into the neighborhood of pathology. Psychotherapy became in such hands essentially a study of hypnotism, with especial interest in its relation to hysteria and similar diseases. The much more essential relation of psychotherapy to the normal mental life, the relation of suggestion and hypnotism to the normal functions seemed too often neglected. Whoever wants to influence the mind in the interest of the patient, must in the first place be in intimate contact with psychology. On the other hand, the minister's spiritual interest brings the facts nearer to religion than they really are. That a suggestion to get rid of toothache, or to sleep the next night, is given by a minister, does not constitute it as a religious suggestion. If the belief in religion simply lies alongside of the belief in most trivial effects, and both are applied in the same way for curing the sick, it is evident that not the spiritual meaning of religion is responsible for the cure, but the psychological process of believing. But if that is the case, it is clear that here again the psychologist, and not the moralist, will give the correct account of the real process involved. In short, it is psychology, psychology in its scientific modern form, which has to furnish the basis for a full understanding of psychotherapy. From psychology it cannot be difficult to bridge over to the medical interests, on the one side, to the idealistic ones on the other side.
Our task here is, therefore, to lay a broad psychological foundation. We must carefully inquire how the modern psychologist looks on mental life and how the inner experiences appear from such a psychological standpoint. The first chapters of this volume may appear like a long, tiresome way around before we come to our goal, the study of the psychotherapeutic agencies. And yet it is the only possible way to overcome the superficiality with which the discussion is too often carried on; we must understand exactly how the psychological analysis and explanation of the scientist differ from the popular point of view. After studying in this spirit the foundation of psychotherapy, we shall carefully examine the practical work, its methods and its results, its possibilities and its limitations. We shall inquire finally into the place which it has to take, looking back upon its history, criticising the present status and outlining the development which has to set in for the future, if a haphazard zigzag movement is not to destroy this great agency for human welfare by transforming it into a source of superstition and bodily danger.
THE PSYCHOLOGICAL BASIS OF PSYCHOTHERAPY
THE AIM OF PSYCHOLOGY
The only safe basis of psychotherapy is a thorough psychological knowledge of the human personality. Yet such a claim has no value until it is entirely clear what is meant by psychological knowledge. We can know man in many ways. Not every study of man's inner life is psychology and the careless mixing of different ways of dealing with man's inner life is largely responsible for the vagueness which characterizes the popular literature of psychotherapy. It is not enough to say that a statement is true or not true. It may be true under one aspect and entirely meaningless under another. For instance, a minister's discussion of man's energies may be full of deep truth and may be inspiring; and yet it may not contain the slightest contribution to a really psychological knowledge of those energies, and would mislead entirely the physician were he to base his treatment of human energies on such a religious interpretation.
Can we not look from different standpoints even on any part of the outer world? I see before me the ocean with its excited waves splashing against the rocks and shore, I see the boats tossed on the stormy sea and I am fascinated by the new and ever new impulses of the tumultuous waves. The whole appears to me like one gigantic energy, like one great emotional expression, and I feel deeply how I understand this beautiful scenery in appreciating its unity and its meaning. Yet would I ever think that it is the only way to understand this turmoil of the waters before me? I know there is no unity and no emotion in the excited sea; each wave is composed of hundreds of thousands of single drops of water, and each drop composed of billions of atoms, and every movement results from mechanical laws under the influence of the pressing water and air. There is hydrogen and there is oxygen, and there is chloride of sodium, and the dark blue color is nothing but the reflection of billions of ether vibrations. But have I really to choose between two statements concerning the waves, one of which is valuable and the other not? On the contrary, both have fundamental value. If I take the attitude of appreciation, it would be absurd to say that this wave is composed of chemical elements which I do not see; and if I take the attitude of physical explanation, it would be equally absurd to deny that such elements are all of which the wave is made. From the one standpoint, the ocean is really excited; from the other standpoint, the molecules are moving according to the laws of hydrodynamics. If I want to understand the meaning of this scene every reminiscence of physics will lead me astray; if I want to calculate the movement of my boat, physics alone can help me.
As long as we deal with outer nature, there is hardly a fear of confusing the various attitudes; but it becomes by far more complex when we deal with man and his inner life. We might abstract entirely from aesthetic appreciation or from moral valuation, we might take man just as an object of knowledge; and yet what we know about him may be entirely different in accordance with our special attitude. Each kind of knowledge may be entirely true, and yet true only from the particular standpoint. Let us consider two extremes. If I meet a friend and we enter into a talk, I try to understand his thoughts and to share his views. I agree or disagree with him; I sympathize with his feelings, I estimate his purposes. In short, he is for me a center of aims and intentions which I interpret: he comes in question for me as a self which has its meaning and has its unity. The more I am interested in his opinions, the more I feel in every utterance, in every gesture, the expression of his will and his purposes; their whole reality for me lies in the fact that they point to something which the speaker intends; his personality lies in his attitude towards the surroundings, towards the world. Yet I may take an entirely different relation to the same man. I may ask myself what processes are going on in his mind, what are the real contents of his consciousness, that is, what perceptions and memory pictures and imaginative ideas and feelings and emotions and judgments and volitions are really present in his consciousness. I watch him to find out, I observe his mental states, I do not ask whether I agree or disagree; his will is for me now not something which has a meaning, but simply something which occurs in his inner experience; his ideas now have for me no reference to something in the world, but they are simply contents of his consciousness; his memories now are for me not symbols of a past to which he refers, but they are present pictures in his mind; in short, what I now find is not a self which shows itself in its aims and purposes and attitudes, but a complex content of consciousness which is composed of numberless elements. I might say in the first place that my friend was to me a subject whom I tried to understand by interpreting his meaning, and in the second case, an object which I understand by describing its structure, its elements, and their connections.
Both ways of looking on man are constantly needed. We might alternate between them in any experience. In the heat of argument, my friend will certainly be for me the subject with whose meanings I try to agree or disagree, whose emotions carry me away, whose ideas open the world to me. Yet in the next moment, I may notice that his ideas were shaped and determined by certain earlier experiences; that they linked themselves in memory according to certain laws of mental flow; that the vividness of his ideas made him overlook certain impressions of the surroundings; and that may turn my attention to an entirely different aspect of his inner life. His feelings and emotions, his volitions and judgments now have for me simply the character of processes which go on and which are observed, which coincide and which succeed each other, which fuse and overlap, and which are composed of smaller parts. My interest is now no longer in the meaning and intentions of this self, but it belongs to the structure and the connections in this system of mental facts. At first, I wanted to understand him by living with him, by participating in his attitudes, and by feeling with his will; now I want to understand him by examining all the processes which go on in his consciousness, by studying their make-up and their behavior, their elements and their laws. In one case I wanted to interpret the man, and finally to appreciate him; in the other case I wanted to describe his inner life, and finally to explain it. The man whose inner life I want to share I treat as a subject, the man whose inner life I want to describe and explain I treat as an object.
I might express these two standpoints still otherwise. If my neighbor is to me a subject, for instance, in the midst of an ordinary conversation, he comes in question only with reference to his aims and meanings: whatever he utters has a purpose and end. I understand his inner life by taking a purposive point of view. On the other hand, the man whose inner life is to me an object can satisfy my interest only if I understand every particular happening in his mind from its preceding causes. I transform his whole life into a chain of causes and effects. My standpoint is thus a causal one. No doubt in our daily life, our purposive interest and our causal interest may intertwine at any moment. I may sympathize with the hopes and fears of my neighbor in a purposive way, and may yet in the next moment consider from a causal standpoint how these emotions of his are perhaps affected by his fatigue or by some glasses of wine, or by a hereditary disposition, or by a suggestion; in short, at one time I look out for the meaning of the emotion as a part of the expression of a self, and at another time for the structure and appearance of the emotion as a part of a causal chain of events. In both directions I can go on with entire consistency, and there cannot be any part of inner experience which cannot be fully brought under either point of view. How far we have a right to mix the two standpoints in practical life, we shall carefully examine; but it is clear that if we want to understand the true meaning of the study of inner life, we have no longer any right carelessly to mix the two standpoints without being conscious of their fundamental difference. We must understand exactly what the aim of the one and of the other is, and where each has its particular value; science certainly has no right to throw together such different views of life. And now this may be said at once: the causal view only is the view of psychology; the purposive view lies outside of psychology.
Such a separation does not at all aim to indicate that the one view is more important than the other, or that the one has more scientific dignity than the other; both yield us truth, and both may be carried from the simplest and most trivial observations of daily life to the highest elaborations of scholarship. To those who are inclined to give all value and all credit only to the strictly psychological view, it may be replied at once that surely our most immediate life experience is carried on by the non-psychological attitude. If we love our family and like our friends, and deal with the man of the street, we are certainly moving in a world of purposive reality. We try to understand each other, to agree and to disagree, to be in sympathy and antipathy, without asking how those volitions and feelings and ideas of other people are built as mental structures, and from what causes they arose; we are satisfied to understand what they mean. In the same way with ourselves. We live our lives by hinging them on our aims and purposes and ideas, and do not ask ourselves what are the causes of our attitudes and of our thoughts.
This purposive view has in no respect to disappear if we move on from our personal intercourse to a scholarly study of reality. The historian, for instance, who tries to understand the will relations of humanity, is the more the true historian the more he sticks to this purposive view of man. The truth which he seeks is to interpret the personalities, to understand them through their attitudes, to make their will living once more, and to link it by agreement and disagreement, by love and hate, with the will of friends and enemies, groups and parties, nations and mankind. It is only a loose popular way of speaking, if this purposive analysis of a character is often called psychological. In a stricter sense of the word, it is not psychological. If the historian really were to take the psychological attitude, he would make of history simply a social psychology, seeking the laws of the social mind, and treating the individual, the hero, and the leader, merely as the crossing-point of psychological law. For such a psychological view the mental life of the hero would not be more important or more interesting than the mental life of a scoundrel, and the psychology of the king would not draw his interest more than the psychology of the beggar. The historian has to shape all that from an entirely different standpoint: his scientific interest depends upon the importance of men's attitudes and actions, and such importance refers to the world of purposes.
In the same way, we have to stick to the non-psychological point of view whenever man's life, his thoughts and feelings and volitions, are to be measured with reference to ideals; that is in ethics and aesthetics and logic, sciences which ask whether the volitions are good or bad, whether the feelings are valuable or worthless, whether the thoughts are true or false. The psychologist does not care; just as the botanist is interested in the weed as much as in the flower, the psychologist is interested in the causal connections of the most heinous crime not less than in those of the noblest deed, in the structure of the most absurd error not less than in that of the maturest wisdom. Truth, beauty, and morality are thus expressions of the self in its purposive aspect.
We can go one step further. Those who narrowly seek every truth only in the scientific understanding, ought to be reminded that this seeking for causal connections is itself, after all, only a life experience which as such is not of causal but of purposive character. "Life is bigger than thought." In the immediate reality of our purposive life we aim towards mastering the world by a causal understanding, and for this end we create science; but this aim itself is then a purpose and not an object. The first act is thus for us, the thinkers, not a part of the causal events, but a purposive intention towards an ideal. Therefore, our purposes have the first right; they represent the fundamental reality; the value of causal connections and thus of all scientific and psychological explanation, depends on the value of the purpose. Causal truth can be only the second word; the first word remains to purposive truth. From this point of view we may understand why there is no conflict between the most consistent causal explanation of mental life on the one side, and an idealistic view of life on the other side; yes, we can see that the fullest emphasis on a scientific psychology—which is necessarily realistic and, to a certain degree, materialistic—is fully embedded in an idealistic philosophy of life, and that without conflict. And we shall see how this consistency in sharply separating the psychological view from the non-psychological, secures much greater safety for true idealism than the inconsistent popular mixing of the two principles, where scientific psychology is constantly encroached upon by demands of faith and religion, and where faith and religion seem constantly in danger of being overturned by new discoveries in physiological psychology. We may, indeed, remove from the start the mistaken fear that a consistent causal aspect of life leads to injustice to the higher aims and ideal purposes of mankind. If we want to have psychology,—and that means if we want to consider the mental life in a system of causes and effects,—we must proceed without prejudices, and without side-thoughts.
From a psychological standpoint our own mental life and that of our neighbor, that of the man and that of the child, that of the normal and that of the insane, that of the human being and that of the animal, are to be considered as a series of mental objects. They are to be analyzed, and to be described, and to be classified and to be explained, just as we deal with the physical objects in the outer world. How are these objects of the psychologist different from the objects of the physicist, from the pebbles on the way and the stars in the sky? There is only one fundamental difference and all other differences result from it. Those outer objects which we call physical, are objects for everybody. The star which I see is conceived as the same star which you see, the table which I touch is the table which you may grasp, too. But every psychical object is an object for one particular person only. My visual impression of the star, that is, my optical perception, is a content of my own consciousness only, and your impression of the star can be a content of your consciousness only. We both may mean the same by our ideas, but I can never have your perception and you can never have my perception. My ideas are enclosed in my mind. I may awaken in your mind ideas which have the same purpose and meaning, but they are new copies in your mind. We both may be angry, but your anger can never be my anger, and your volitions can never enter my mind. Every possible psychical fact thus exists in one consciousness only, while every physical fact exists for every possible consciousness.
The psychologist's final task is to explain the appearance and disappearance, the connections and sequences of these mental objects, the contents of consciousness. But before he can start on explanation of the facts, he has to describe them, and describing means analyzing them into their elements and fixating those elements and their combinations for an exact report. Such descriptive work is in a way preparatory for the further task of real explanation; yet it is in itself important, complicated, and difficult. Of course, it may be easy to separate the complex content into some big groups of facts, to point out that this is a memory idea and this an imaginative idea and the other an abstract idea, and this a perception and that a feeling, this an emotion and that a volition. But such clumsy first discrimination does not go further, perhaps, than does the naturalist's, who tells us that this is a mountain and that a tree, this a pond and that a bird. The real description would demand, of course, an exact measurement of the height of the mountain and the geological analysis of its structure, or an exact classification of the tree and the bird, with a complete description of their organs, and in each organ the various tissues have to be described, and in each tissue the various cells, and the microscopist goes further and describes the structure of the cell. Certainly in the same way the psychologist has to go on to resolve every one of those complex structures; he has to examine the mental tissues and the mental cells of which a volition or a memory idea or a perception are composed. And while he cannot use a microscope for these mental elements, yet his studies may cause elements to appear which the naive observation remains entirely unaware of.
Perhaps he finds in his consciousness the perception of the table before him which lingers for a little while in his mind. He finds no difficulty in analyzing it into color sensations and tactual sensations; and yet he is aware of so much more in it. The table, for instance, has form for him and he may find that these form perceptions involve the sensations of the eye movements which he makes from one corner of the table to the other; he may find that if the idea lasts in him, he becomes aware of the time by sensations of tension; he finds that in his perception of the table lies an idea of its use, and he discovers that that is made up of elements which are partly memory reproductions of earlier impressions, partly sensations of movement impulses; he also finds that the table feels smooth, and he discovers by his analysis that this impression of smoothness results from a special combination of tactual sensations and movement sensations; and again those movement sensations he analyzes further into sensations of muscle contraction and sensations of pressure in the joints and sensations of tension in the tendons. Before a zooelogist has completed his description of a bird in the landscape, he has given account of hundreds of thousands of things; but before the psychologist would complete the enumeration of the mental elements which enter into the seeing of the table, he would have to give account of by far more psychical elements. Every point in the surface of the table has its own light value, perhaps different in its quality and intensity and saturation, in its hue and tint and shade from the next one, and at whatever point of the table's edge our attention is directed, each one involves numberless shades in the vividness of all the other points and numberless mental relations of space perception among the various parts of the table. In the thorough analysis of the describing psychologist, every single idea, and in the same way, every single emotion or feeling or judgment becomes complex like a living organism, an aggregate of thousands of mental tissues, and yet made up from "the stuff that dreams are made of."
But there is one particular difficulty which makes the psychological description so much harder than that of the physicist, and which gives rise to many disagreements and discussions in psychological literature. The psychologist has not only to tear the complex into pieces and thus to seek the elements, but he has to fixate those elements for the purpose of communication, as, of course, a scientific description demands that he be able to give account to others of what he experiences. The physicist has no difficulty whatever in that line because, as we saw, the world of physical things is the world which all men are sharing together. Every element which I find in it, I can show to every other person, and if I cannot show that particular thing, because I cannot yet carry the mountain to another place, then I can at least measure it, as we share those standards of space. Thus natural science has in its objective measurements the possibility of describing every part of the physical world. The psychical world, on the other hand, is as we saw, the world which is private property. Every effort at description is thus entirely in vain as long as our mental facts cannot somehow be linked with physical happenings. If I say that I have in my mind sweetness or sourness, or bitterness or saltness, I cannot carry any understanding to anyone else and therefore cannot give any description until I have agreed that I mean by sweetness the sensation which sugar gives me, and by saltness the sensation of salt. The sugar and salt I can point out to my neighbor and only in that way I understand what he means if he says that he tastes salt and sweet; otherwise I should have no means whatever to discriminate whether that which he calls a sweet taste sensation is not just what I call headache. Where no such direct relation for a physical thing is known, description of the mental element would remain impossible. Of course, every perception of the outer world, all our seeing and hearing, and touching and tasting, offers us at once such definite connection between the inner experience and a piece of the physical universe. Our own organism is also such a piece of physical nature: just as I describe my tasting or touching, I may describe the perception of my arms and legs or my inner organs. Thus everything which is material of perception gives us a handle for a real psychological description. Psychology usually calls the elements of these perceptions sensations. Whatever is composed of sensations is thus describable.
On the other hand, no other way of description is open. If there were mental states which are composed of other elements than sensations, they would necessarily remain indescribable; we could not grasp them because they would not have any definite relation to the common physical world. We might say, for instance, that our mental content is made up of sensations and feelings, but if such feelings were really entirely different from sensations, they would have to remain for all time mysterious and unknown. We could not compare notes. The feeling which I call joy may feel just like the one which you call despair. The consistent development of modern psychology and its emancipation from vagueness and superficial analysis became possible only through the fact that such recourse to indescribable elements has become unnecessary. Modern psychology has been able to demonstrate more and more that the same elements which constitute our perceptions are also the elements of the other contents of consciousness. In other words modern psychology has recognized that the volitions and emotions and feelings and judgments, and the whole stream of inner life, are made up of sensations. Millions of sensations in all degrees of vividness and clearness, of intensity and fusion, in endless manifoldness of rhythms and relations constitute their whole content. It is a discovery quite similar to the one which chemistry made when it found that the same elements which are part of the inorganic substances are also the only possible elements of the organic world.
From a strictly psychological standpoint, the ideas and the not-ideas contain thus nothing but sensations. Their grouping, their shading, their combination, their succession decide whether we have before us a perception or an imagination, a volition or an emotion. What are we ourselves then for the psychologist? Evidently we ourselves belong also to the inner experiences which we know; and psychology has succeeded in analyzing this idea of our own self just in the same way as it analyzes our idea of the moon. In this analysis, psychology finds its idea of the self as a content of consciousness crystallized about the sensations from the body. Every one of our bodily activities is represented in our consciousness by movement sensations, and these sensations form the core of the complex aggregate which develops into the idea of ourselves. Organic sensations from our inner organs, pain sensations and pleasure sensations fuse with the movement sensations, and the whole complex shapes itself slowly into the idea of the personality of the self in contrast to the idea of other personalities. We ourselves are for ourselves a complex combination of sensations; and yet all our feelings and emotions and volitions are only a part of it. Psychology thus necessarily considers those experiences of feeling and will and character simply as changes in the midst of that central experience of personality which is itself made up of bodily sensations. Each bit of will and emotion must be decomposed into its finest elements. There is no passing mood, and no floating half-thought in our mind, no dream and no intuition, no slightest change of attention, no instinct and desire which cannot be analyzed thus into its sensation elements or rather which must not be analyzed, if we are to describe it at all, and that means if we are to give a psychological account. Psychology is endlessly far from this ideal to-day. It has been claimed, not without justice, that psychology has reached to-day only the level which physics attained in the seventeenth century; but psychology must insist that its ideal lies in this direction. No one takes a real psychological view of the human mind who does not understand this endless complexity of the material, and who does not see that even the simplest mental state practically presents a most complex problem to scientific analysis. The physician who really aims towards scientifically exact influence on the human mind has reached the first step of his preparation as soon as he understands that the content of consciousness is composed of hundreds of thousands of elements. To treat the mind as if there were only a few large pieces, one thing called memory and one thing called will and one called emotion and so on, is as if a surgeon were to perform an operation, knowing that there are arms and legs, but not knowing the ramifications of the nerves and blood-vessels which his knife may injure. Yet the description of these complex facts is only the beginning of psychology. We saw that the real aim is their explanation.
MIND AND BRAIN
The central aim of the psychologist must be to explain the mental facts. It is not sufficient to describe the procession of mental experiences in us, we must understand the causes which determine that now this and now that appears and disappears, and appears just in this combination of elements. The astronomer is not satisfied with describing the stars, he wants to explain their movements and to determine which movements are to be expected. The psychologist, like the naturalist, aims towards explanation, and it is this demand which forces him to look from the psychical facts to the physical ones, from the mind to the brain. He is under an illusion if he fancies that he can explain mental facts by themselves. The purposive mind has its connection in itself, the causal psychological mind demands for its connection the body. To understand this necessity is the first step towards understanding the relation of mind and brain.
The psychologist's problem of explanation is in one way entirely different from that of the physicist. The physicist finds a world of an unlimited number of atoms which are ultimately conceived as all alike, but each one in a different place, and all the changes in the universe, the movements of the stars, the waves of the ocean, are to be explained by the causal connections of the movements of these atoms. The psychologist, on the other hand, finds an endless manifoldness of elements which are not in space, and which have no space form whatever. My will is neither triangular nor oval; my emotion is neither shorter than five feet nor longer; my memory image of a melody has no thickness and no tallness; my contents of consciousness are as such not in space; their elements cannot pass through any space movements like the atoms of the physicist. Instead of it, the psychical atoms, the sensations, have different qualities, are blue and green, and cold and warm, and sweet and sour, and toothache and headache. The changes which go on in such a system are thus not changes of position and movements, but changes in kind and strength and vividness and fusion; and exactly such changes are the processes which the psychologist wants to explain. He wants to make us understand why this idea grows up and the other fades away, why this impression stands out with clearness as an attended object while the other lacks vividness and disappears, why this volition grows out of that emotion, why this feeling leads to this imaginative thought.
The first step towards such explanation is, of course, in psychology, as in all other sciences, the careful observation of regularities. It quickly leads us to formulate some general laws. Psychology has known, for instance, for two thousand years, that if we have perceived two things together, and later we see the one again, the new perception brings us a memory image of the other thing. If we saw a man's face and heard at the same time his name, seeing his face may later awaken in us the memory of his name, or the hearing of his name may later awaken in us a reproduced memory image of his face. On such a basis, for instance, we formulate some general laws of association of ideas, and as soon as we have such laws laid down, we consider the appearance of such a memory image by association as sufficiently explained. We feel that it gives us sufficient basis to predict that in the future this idea will stir up in us the other idea. Psychology has formulated plenty of such general statements, and they serve well for a first orientation.
Yet can this ever be considered as a last word of scientific explanation of psychical facts? Can psychology really in this way reach an ideal similar to that of scientific astronomy or chemistry? Would the scientist of nature ever be satisfied with this kind of explanation, which is nothing but generalization of certain sequences? Does not the explanation of the naturalist contain an entirely different element? He does not merely want to say that this effect has sometimes been observed and that there is thus probability that it will come again, when similar causes are given. No, the physicist wants to understand those connections of cause and effect as necessary ones. He tries to find sequences which cannot be otherwise because they cannot be thought in any other way. Therefore he is not satisfied with complex regularities, but analyzes them until he can bring them down to simple physical connections, and these physical connections finally to mechanical processes, which realize for us logical necessities. That matter lasts and cannot disappear is such a presupposition, which comes to us with the necessity of logical thinking. We simply cannot think it otherwise. And the whole idea of natural science is to conceive the physical universe in such a way that all changes in the outer world can be understood as the movements of its parts in accordance with such necessary physical axioms. If we knew all the atoms of the present status of the universe, and we knew every present movement of every atom, we should be able to foresee the position of every atom in the next moment and in the following moment and in all following moments, and all that by the necessary continuation of the substance and its energies. That alone is the background of all special physical inquiry, and we rely on the special laws of physics and chemistry, because we trust that this universe, as a whole, could be ultimately understood as such a system of necessary changes in the positions of the lasting atoms.
For the psychologist there is no hope of finding such necessity in the mental processes. The point is not that psychology is to-day too far removed from the fulfillment of such an ideal, the point is rather that such an ideal would be meaningless for the psychologist. His materials, the psychical contents of consciousness, are by their nature unfit to enter into such necessary connections; they cannot do it because they cannot last. The physical object, we saw, is the object which is common property, which we all feel in common, which must thus exist for all time. The things in nature may burn down or decay, but no atom of them can ever disappear from the universe, each must enter into new and ever new combinations and last through all changes. The psychical thing, on the other hand, can exist only for the one immediate experience. Every sensation which enters into my ideas or volitions or emotions is a new creation of the instant which cannot last; each one flashes up and is lost with the moment's experience. My will to-day may have the same aim as my will of yesterday, but as psychical object, my will to-day is a new will, is a new creation in every pulse beat of my life. I must will it again, I cannot store it up. And my joy of to-day can never be as psychical fact the same joy which I may have to-morrow. Mental objects as such, as psychological material, are not destined to last. It has no meaning whatever to think of their being kept over until another time. It is a coarse materialism to conceive the mental contents like pebbles which may remain on the road from one day to another. Our ideas and feelings are mental appearances which have their existence in the act of the one experience; each new experience must be an entirely new creation.
If I remember my last year's perception, I do not dig it out from an under-mind, in which it was stored up and buried, but I create an entirely new memory picture, just as I may make to-day a speech which says the same thing which I said last year, and yet my action of speaking is not last year's speech movement. It is a new action, and the movement did not lie over somewhere during the interval. Mental life is produced anew in every moment. When the first experience is gone and the second comes, nothing of the stuff from which the first was made still has existence in the content of consciousness. By this fact it becomes entirely impossible ever to conceive necessary connections in the sense of physical necessity in the world of consciousness. The one idea may bring to me another idea by association, but as long as I consider both strictly as mental facts, I can never understand why this association happens, I can never grasp the real mechanism of the connection, I can never see necessity between the disappearance of the one and the appearance of the other. It remains a mystery which does not justify any expectation that the same sequence will result again. Whatever belongs to the psychical world can never be linked by a real insight into necessity. Causality there remains an empty name without promise of a real explanation.
Only when we have recognized this fundamental difficulty in the efforts for psychological explanation, can we understand the way which modern psychology has taken most successfully. The end of this way is simply this: every psychical fact is to be thought of as an accompaniment of a physical process and the necessary connections of these physical processes determine, then, the connections of the mental facts. Indeed this has become the method of modern psychology. It has brought about the intimate relation between psychology and the physiology of the brain, and has given us, as foundation, the theory of psychophysical parallelism; the theory that there is no psychical process without a parallel brain process. But the real center of the theory lies indeed in the fact which we discussed; it lies in the fact that we cannot have any explanation of mental states as such at all, if we do not link them with physical processes.
Is it necessary to express again the assurance that such statements of a parallelism between mind and brain in no way interfere with an idealistic view of inner life? Have we not seen clearly enough that these mental facts which are conceived parallel to physiological brain processes do not represent the immediate reality of our inner life, that our life reality is purposive and as such outside of all causal explanation, and that we have to take a special, almost artificial, point of view to consider inner life at all as objects, as contents of consciousness, and thus as psychological material? But since we have seen that for certain purposes such a point of view is necessary, as soon as we have taken it we must be consistent. Our inner life in its purposive reality has therefore nothing to do with brain processes, but if we are on the psychological track and consider man as a system of psychological phenomena, then to be sure, we must see that our only possible interest lies in the finding of necessary causal connections. But these cannot be found otherwise than by linking the mental facts with the physical ones, the psychological material with the processes of the brain.
Of course, that mental experience stands in intimate relations to the body is a knowledge which does not wait for such philosophical arguments. That mind and body come in contact is a conviction which goes with every single sense perception. I see and hear because light and sound stimulate my sense organs, and the sense organs stimulate my brain. The explanation of perception through causes in the physical system seems the more natural as it is evident that in such cases there are no psychical causes which might have brought forward the perception. If I suddenly hear bells ringing, there was on the mental side nothing preceding which could be responsible for my sound perception. And the same holds true if the physical source lies in my own body, if perhaps my tooth begins to ache, although no expectation preceded it.
In the same way it seems a matter of course that mind and body are connected wherever an action is performed. I have the will to grasp for the book before me, and obediently my arm performs the movement; the muscles contract themselves, the whole physical apparatus comes into motion through the preceding mental fact. The same holds true where no special will act arouses the muscles. If a thought is in my mind and it discharges itself in appropriate words, those words are after all as physical facts the movements of lips and tongue and vocal cords and chest; in short, a whole system of physical responses has set in through a mental experience. But the same thought may be the starting-point for many other bodily changes; it may make me blush, and that means that large groups of blood-vessels become dilated; or I may get pale, the blood-vessels are contracted. Or I may cry, the lachrymal gland is working; or it may spoil my appetite, the membranes of my stomach cease to produce; or my muscles may tremble, or my skin may perspire; in short, my whole organism may resound with mental excitement which some words may set up.
But it is not only the impression of outer stimuli and the expression of inner thoughts in which mind and body come together. Daily life teaches us, for instance, how our mental states are dependent upon most various bodily influences. If the temperature of the blood is raised in fever, the mental processes may go over into far-reaching confusion; if hashish is smoked, the mind wanders to paradise, and a few glasses of wine may give a new mental optimism and exuberance; a cup of tea may make us sociable, a dose of bromide may annihilate the irritation of our mind, and when we inhale ether, the whole content of consciousness fades away. In every one of these cases, the body received the chemical substance, the blood absorbed and carried it to the brain, and the change in the brain was accompanied by a change in the mental behavior. Even ordinary sleep at night presents itself surely as a bodily state—the fatigued brain cells demand their rest, and yet at the same time the whole mental life becomes entirely changed. It is not difficult to carry over such observations of daily life to the more exact studies of the psychological laboratory and to examine with the subtle means of the psychological experiment the mental variations which occur with changes of physical conditions. We might feel, without instruments, that our ideas pass on more easily after a few cups of strong coffee, but the laboratory may measure that with its exact methods and study in thousandth parts of a second, the quickening or retarding in the flow of ideas. Every subjective illusion is then excluded, our electrical clocks, which measure the rapidity of mental action and of thought association, will show then beyond doubt how every change in the organism influences the processes of the mind. Bodily fatigue and indigestion, physical health and blood circulation, everything, influence our mental make-up. In the same way it is the laboratory experiment which shows by the subtlest means that every mental state produces bodily effects where we ordinarily ignore them. As soon as we apply the equipment of the psychological workshop, it is easy to show that even the slightest feeling may have its influence on the pulse and the respiration, on the blood circulation and on the glands; or, that our thoughts give impulse to our muscles and move our organs when we ourselves are entirely unaware of it.
Again we may turn in another direction. Pathology shows us how every physical disablement of the brain is accompanied by mental processes. If the blood supply to the brain is cut off, we faint; a blow on the head may wipe out the memory of the preceding hours, and a hemorrhage in the brain, the bursting of a blood vessel which destroys groups of brain cells, produces serious defects in the mental content. A tumor in the brain may completely change the personality; the bodily disease of certain convolutions in the brain brings with it the loss of the power of speech; paralysis of the brain dissolves the whole mental personality. Physical inhibition in the growth of the brain involves, on the mental side, feeble-mindedness and idiocy. Of course, all this is not sufficient to bring out a definite parallelism between special mental functions and special physical processes, as the phenomena are extremely complex. If a patient who has suffered from a mental disturbance dies, and his brain is examined, there is no simple correlation before us. It may be difficult to diagnose exactly the mental symptoms. If we have heard that the man was unable to read, we do not know from that what really happened in his brain. He may not have read because he did not see the words, or because the letters were confusing, or because he had lost memory for the meaning, or because he had lost the impulse to speak the words, or because he felt unable to turn his attention, or because the impulse to read aloud was not carried out by his organism, or because an inner voice told him that it is a sin to read, or for many similar reasons; and yet each one represents psychologically an entirely different situation. On the other hand, on the physical side, the destruction is probably not confined to one particular spot. Complications have crept over to other places or the disturbance in one part works as inhibitory influence on other brain parts, or a tumor may press on a far-removed part, or the disturbance may be one which cannot be examined with our present microscopic means. In short, we have always a complex mental situation and a complex physical one, and to find definite correlations may be possible only by the comparison of very many cases.
Other methods, however, may supplement the pathological one. The comparative anatomist shows us that the development of the central nervous system in the kingdom of animals goes parallel to the development of the mental functions, and that it is not only a question of progress along all lines. Any special function of the mind may have in certain animal groups an especially high development, and we see certain parts correspondingly developed. The dog has certainly a keener sense of smell than the man—the part of the brain which is in direct connection with the olfactory nerve is correspondingly much bulkier in the dog's brain than in the human organism. Here too, of course, research may be carried to the subtlest details and the microscope has to tell the full story. Not the differences in the big structure, but the microscopical differences in the brain cells of special parts are to be held responsible. But comparison may not be confined to the various species of animals; it may refer not less to the various stages of man. The genetic psychologist knows how the child's mind develops in a regular rhythm, one mental function after another, how the first days and first weeks and first months in the infant's life have their characteristic mental possibilities, and no mental function can be anticipated there. The new-born child can taste milk, but cannot hear music. The anatomist shows us that correspondingly only certain nervous tracts have the anatomical equipment by which they become ready for functioning. Most of the tracts at first lack the so-called medullar sheath, and from month to month new paths are provided with this physical equipment.
Finally we have the experiment of the physiologist. His vivisectional experiments, for instance, demonstrate that the electrical stimulation of a definite spot on the surface of a dog's brain produces movements which we should ordinarily take as expressions of mental states, movements of the front legs or of the tail, movements of barking or whining. On the other hand, the dog becomes unable to fulfill the mental impulses if certain definite parts of his brain are destroyed. The physiologist may show from the monkey down to the pigeon, to the frog, to the ant, to the worm, how the behavior of animals is changed as soon as certain groups of nervous elements are extirpated. It is the mental emotional character of the pigeon which is changed when the physiologist cuts off parts of his brain. In short, stimulation and destruction demonstrate, by experiments which supplement each other, that mental functions correspond to brain functions.
There is thus no lack of demonstration from all quarters that mental facts and brain processes belong together; and yet, however much we may cumulate such popular and scientific observations, they would never by themselves admit of the sweeping generalization that there cannot be any mental state which is not accompanied by a process in the central nervous system. Someone might say, to be sure, the perceptions and memory images, the volitions and instincts and impulses, have their physiological basis, but there remain after all acts of attention, or decisions, or subtle feelings, or flights of imagination, which are independent of any brain action. Here, indeed, observation cannot settle such a general principle. Its real hold lies in the fact with which we started: there is no causal connection in the mental states as such. If we want to understand mental facts as such in a chain, of causal events, we have first to conceive them as parallel to physical events. The principle of psychophysical parallelism, that is, the principle that every psychical process accompanies a physiological change is thus not a mere result of observation. It is simply a postulate. Every science begins with postulates and only that which fulfills such postulates has the dignity of truth in the midst of that scientific realm. The astronomer cannot find by observation that there is no star the movements of which are not the effects of foregoing causes. He knows it beforehand, he demands it, he does not recognize any movement as understood until he has found the causes, he presupposes that such causes exist, that no star moves simply by a magic power, and that nowhere in the astronomical universe is the chain of causality broken. He postulates it, and where he does not discover the causes, he is sure that he has not solved the real problem.
In the same way the psychologist who aims towards explanation of mental facts must postulate that there cannot be any mental state which is not an accompaniment of a physical brain process, and is as such connected through physical means with the preceding and the following events in the psychophysical system. Only when such a general framework of theory is built up by a logical postulate, is the way open to make use of all those observations of the laboratory and of the clinic, of the zooelogist and of the anatomist. It is the theory which has to give the right setting to those scattered observations. However far we may be from being able to point to the special brain process which lies at the bottom of the higher mental state, we know beforehand that there is no shadow of an idea, no fringe of a feeling, no suggestion of a desire which does not correspond to definite processes in the brain. The details may and must be material for diverging theories, but the conflict of such hypothetical opinions has nothing to do with the certainty of the underlying conviction that if we knew the whole truth, we should recognize every single mental happening as parallel to physical processes in the nervous system. To explain mental facts means to think them as parallel to the brain processes which have their own causal connections in the physical world.
We started, for instance, from the old observation that two impressions which come to our mind at the same time have a tendency to reawaken one another; and we saw that psychology was well able to formulate these facts in general statements of the association of ideas. But we realized that that in itself is not really explanation. If the odor which we smell awakes in us the name of a chemical substance, and if we now bring this under the general heading of association of ideas, an explanation is not really given by it. That smell sensation itself is not really understood as a cause of those sound sensations of the word. We have no insight into the connection of those two happenings. But the situation is entirely changed, if we consider the smell effect from the point of view of the parallelistic theory. Now the association of facts would indicate that we got the first two impressions together, because two brain processes were going on at the same time. My nose brought me the smell stimulus, my ear gave me the sound stimulus, each going on in a particular center, or, to express it in a simplified schematic way, each reaching particular brain cells, and the excitement of these brain cells being accompanied by the particular sensations. The physiologist has many possibilities of conceiving the further stages of the process, in order to satisfy the demand of explanation. He may say the excitement of each of these two brain cells, the one in the olfactory center, the other in the auditory center, irradiates in all directions through the fine branches of the brain fibers. Each cell has relations to every other cell in the brain; thus there is also one connecting path between those two cells which were stimulated at once. Now if the two ends of an anatomical path are excited at the same time, the path itself becomes changed. The connecting way becomes a path of least resistance, and that means that if, in future, one of the two brain cells becomes excited again, the overflow of the nervous excitement will not now go on easily in all directions, but only just along that one channel which leads to that other brain cell. A theory like this explains in real explanatory terms, in ways which physics and chemistry can demonstrate as necessary, that any excitement of the odor cell runs over into the sound cell and vice versa. In short, the psychological association of ideas, which we should simply have to accept as inexplainable fact, is thus transformed into a connection which we understand as necessary; and the fact is really explained.
This simple scheme of the physiology of association for a hundred years has given a most decided impulse to the progress of psychology. As the association process can so easily be expressed in physiological terms, the aim was prevalent to understand the interplay of mental life more and more as the result of association. The underlying thought of this whole association psychology was thus a conviction that whenever two mental experiences occur together, either of them keeps the tendency to reawaken the other at a later time. Through the endless combination which life's impressions awaken in the mind from the first hour after birth, the whole stream of memory images and thoughts and aims and imaginations is thus to be explained.
The whole theory of physiological associationism works evidently with two factors. First, there are millions of brain cells of which each one may have its particular quality of sensation, and second, each brain cell may work with any degree of energy, to which the intensity of the sensation would correspond. If I distinguish ten thousand different pitches of tone, they would be located in ten thousand different cell groups, each one connected through a special fiber with a special string in the ear. And each of these tones may be loud or faint, corresponding to the amount of excitement in the particular cell group. Every other variation must then result from the millionfold connections between these brain cells. Indeed, the brain furnishes all possibilities for such a theory. We know how every brain cell resolves itself into tree-like branch systems which can take up excitements from all sides, and how it can carry its own excitement through long connecting fibers to distant places, and how the endings of these fibers clasp into the branches of the next cell, allowing the propagation of excitement from cell to cell. We know further how large spheres of the brain are confined to cells of particular function, that for instance cells which serve visual sensations are in the rear part of the brain hemispheres, and so on. Finally we know how millions of connecting fibers represent paths in all directions, allowing very well a cooeperation by association between the most distant parts of the brain. The theories found their richest development, when it was recognized that large spheres of our brain centers evidently do not serve at all merely sensory states, but that their cells have as their function only the intermediating between different sensory centers. Such so-called association centers are thus like complex switchboards between the various mental centers. Their own activity is not accompanied by any mental content, but has only the function of regulating transmission of the excitement from the one to the other. Above all their operation would make it possible that through associative processes, the wonderful complexity of our trains of thought may be reached.
Yet even the highest development of the association theories did not seem to do justice to the whole richness of the inner life. We may well understand through those association processes that a rich supply of memory pictures is at our disposal, that ideas stream plentifully to our minds and enter into new and ever new combinations. But that alone is not an account of our inner experience. If there is anything essential for inner life, it is the attention which gives emphasis to certain states and neglects others. And that means that certain mental contents are growing not only in strength but in vividness and clearness, and that others are losing their vividness, are inhibited and suppressed. Here were always the real difficulties of the association theories; they seemed so entirely unable to explain from their own means why certain states become foremost in our minds and others fade away, why some have the power to grow and others are neglected. These facts of attention and vividness, inhibition and fading, worked almost as a temptation to give up the physiological explanation altogether and to rely on some mystical power, some mental influence which could pull and push the ideas without any interference and help from the side of the brain. Yet since we have seen that the truth of psychophysical parallelism has the meaning of a postulate which we cannot escape unless we want to give up explanation altogether, it is evident that such falling back into un-physiological agencies would be just as inconsistent as if the naturalist should posit miracles in the midst of chemistry or astronomy. If the facts which cluster about attention cannot be understood by the simple scheme of associationism, the demand must be for a better physiological theory.
The development of physiological psychology in recent years has indeed shown the way to such a wider theory, which furnishes the physiological accompaniment also for those experiences of attention and vividness which form the weakness of associationism. This new development has come up with the growing insight that the brain's mental functions are related not only to the sensory impressions, but at the same time to the motor expressions. The older view, still prevalent to-day in popular writings, made the brain the reservoir of physical stimuli, which come from the sense organs to the cortex of the brain hemispheres. There the perceptions arose and through associative interplay the memory pictures and the ideas of action and the feelings arose, and the whole inner life was thus bound up with the processes in these sensorial spheres. When the mind had done its work, finally an impulse was sent to some motor apparatus in the brain which then sent off the impulse to some acting muscles. That whole motor part was thus a kind of appendix to the brain process. The psychical life had nothing to do with it but to give the command for its action. The process in the motor part thus began when the mental proceeding was completed. But it became clear that this view was only the outgrowth of the strong interest which physiology took in the sense processes. If a neutral fair account of the brain actions is attempted, there can hardly be doubt that this whole sensorial view of the brain is only half of the story and that the motor half has exactly the same right to consideration. The cortex of the brain, the functions of which are accompanied by mental processes, is always and everywhere not only the recipient of sensory stimuli but at the same time the starting point of motor impulses. That which is centripetal, leading to the cortex, is therefore not more important for the central process than that which is centrifugal, leading from the cortex. The cortex is the apparatus of transmission between the incoming and the outgoing currents, between the excitements which run to the brain and the discharges which go from the brain, and the mental accompaniments are thus accompaniments of these transmission processes. If the channels of discharge are closed and the transmission is thus impossible, a blockade must result at the central station and the accompanying mental processes must be entirely different from those which happen there when the channels of discharge are wide open. Here too all the special theories are still in the midst of tumultuous discord. Yet this new emphasis on the motor side of the psychical process seems to influence modern psychology more and more.
Nobody can deny that first of all this is the necessary outcome of a biological view of the brain. What else can be the brain's function in the midst of nature than the transforming of impressions into expressions, stimuli into actions? It is the great apparatus by which the organism steadily adjusts itself to the surroundings. There would be no use whatever biologically in a brain which had connections with the sense organs, but which had no connections with the muscular system, and on the other hand, a brain which had motor nerves and muscular adjustment would be entirely useless if it had not sensory nerves and sense organs connected with it. In the one case the world would be experienced, but no response would be possible; in the other case, the means for response would be given, but no adjustment could set in because no experience of the surroundings would be possible. Adjustment every moment demands the relation of the brain in both directions. Through the sensory nerves the brain receives; through the motor nerves the brain directs, and this whole arc from the sense organs through the sensory nerves, through the brain, through the motor nerves and finally to the muscles, is one unified apparatus of which no part can be thought away. The brain in itself would be just as useless for the organism as the heart would be without the arteries and veins.
We must keep this intimate and necessary relation between the sensory and motor parts constantly in view, and must understand that there cannot be any sensory process which does not go over into motor response. Then only the ways are open to develop physiological views which give a physical basis to the processes of attention and vividness and inhibition, just as well as to the processes of memory and association. Such motor theories take many forms. Perhaps we shall most quickly bring the most essential factors together, if we say that full vividness belongs only to those sensations for which the channels of motor discharge are open, while those are inhibited for which the channels of discharge are closed; and any channel of discharge is closed, if action is proceeding in the opposite channel. If I open my hand, the motor paths which lead to closing my fist are blocked; and if I close my fist, the channels which lead to the opening of the hand are closed. Now if only those ideas are vivid which find the channels open, it is clear that all the ideas which would lead to the opposite action have no chance for development; they remain inhibited, and just this relation between the vividness of certain ideas and inhibition for those ideas which lead to the opposite action is the characteristic of the process of attention.
From such a point of view, the total mental life can be brought into the psychophysical scheme. We now have not two variable factors, but three, namely, the qualities of the elements, the intensities of the elements, and, as a third, the vividness of the elements. The quality corresponds, as we saw in the association theory, to the local position and connection of the brain cells; the intensity corresponds to the energy of the excitement; and the vividness, we may add now, corresponds to the relation to motor channels. The whole mental life thus becomes the accompaniment of a steady process of transmitting impressions and memories into reactions. That every experience involves millions of such elements we saw when we spoke of the description of mental life. The effort to explain mental life shows us now that this millionfold manifoldness belongs to a system of reactions of which all parts are in steady correlation: a moving equilibrium of unlimited complexity. Surely no one can reduce this wonderful manifoldness to those clumsy concepts with which popular psychology is reporting the story of the mind and its relations to the brain.
It may seem that such a psychological view of inner life annihilates that which we feel as the most essential characteristic of our inner experience, its unity and its freedom. In one sense that is certainly true. In the real life which we live and fight through, where our duties and our happiness lie, we know a unity and freedom of our personality which psychology must destroy. Of course that does not mean that psychology denies the truth of that freedom and unity. Moreover it would condemn itself if it were to deny that which gives meaning to the endeavors of our life and thus also to every search for truth. Psychology claims only that we must abstract from it, when we take the psychological standpoint towards life. Freedom of our real life means that we must know ourselves in the midst of our life work as guided by aims and obligations, and that in this purposive existence of ourselves we do not feel ourselves as determined by causes. I will the fulfillment of my ideals only because I will them. That this will itself may be the effect of foregoing causes is an aspect which does not belong to my naive experience. Our freedom means that in our real life our will is not related to causes, that the point of view of causality is thus meaningless for the value of our achievements. And the other man's will too comes in question for us as something to be interpreted and to be appreciated, but not to be explained by connection with causes. As long as we move in this sphere of purposive interest, we are free and deal with free selves; but if in the midst of these free aims, the will arises to consider the actions of others and of ourselves from the standpoint of causality, then we have ourselves decided to enter a new sphere in which it would be meaningless to seek for any will which is not determined by causes. As soon as we have chosen the psychological standpoint and are in the midst of the work of causal reconstruction, any will which is not understood as determined by causes is simply an unsolved problem. In the midst of a causal construction, absence of causes would never mean real freedom.
In that purposive world of immediate life experience, we also are unities inasmuch as we ourselves know us as the same in every new will of ours. We remain identical with ourselves because every purpose is posited in the midst of, and bound up with, the general purpose of ourselves. And in this internal unity of meaning, nothing breaks ourselves into pieces, and the whole manifold of experience is thus expressed by a personality which knows itself in its purposive unity. But this unity again is denied by our own intention as soon as we decide to take the causal view of inner life. The purposive unity must now transform itself into an endless complexity, and our own self becomes a composite of hundreds of thousands of elements.
On the other hand, all this does not mean that psychology cannot have its own consistent conception of the mind's unity and freedom. Our psychological mind is a unity because its manifold is a system in which all parts hang together. A change in any one part involves changes in the whole system. The interrelation, to be sure, is not a strictly psychical one, for we have seen that the causal connection as such appears at the physical side. But, inasmuch as there is no psychical process which does not belong to a physiological one, the interconnection of the mental facts is complete and involves the totality of neural processes of which after all a small part only has its psychological record. We might compare those hundreds of millions of neurons in each brain with the hundreds of millions of individuals who make up the population of the nations, and the psychical accompaniment we might compare with the written historical record of mankind. The written records themselves have no direct interconnection, they are only accompaniments of what happens in these millions of men. And again only the higher layer of the neurons in the population sees its doings recorded in the annals of history; and yet whatever those leaders of action and thought and emotion may achieve is dependent upon and working on the actions of those millions of subcortical population neurons. The historical record has its unity through the interrelation of all parts of historical mankind.
But after all the psychologist has no less a right to speak of freedom. Of course his freedom cannot mean exemption from causality. Whatever happens in the psychological system must be perfectly determined by the foregoing causes. But the psychologist has good reason to discriminate between those actions which result from the normal psychophysical factors and such actions as result from broken machinery. If the brain is poisoned by alcohol or in fever, if an infectious disease has destroyed the brain cells, action is no longer the outcome of the normal cooeperation of the organs, and even those clusters of neural activities which are accompanied by the consciousness of the own personality lose their control of the motor outcome. The man in delirium or paralysis acts without causal connection with his past; the action is, therefore, not the product of his whole personality, and the psychologist is justified in calling the man unfree. But, whenever the motor response results from the undisturbed cooeperation of the normal brain parts, then the inherited equipment and the whole experience and the whole training, the acquired habits and the acquired inhibitions will count in bringing about the reaction. This is the psychological freedom of man. The unity of an interconnected composite and the freedom of causal determination through normal cooeperation of all its parts characterize the only personality which the psychologist has to recognize.
PSYCHOLOGY AND MEDICINE
We are now ready to take the first step towards an examination of the problem of curing suffering mankind. So far we have spoken only of the meaning of psychology, of its principles and of its fundamental theories as to mind and brain. We have moved in an entirely theoretical sphere. Now we approach a field in which everything is controlled by a practical aim, the treatment of the sick. Yet our discussion of psychology should have brought us much nearer to the point where we can enter this realm of medicine. Everything depends on the right point of entrance. That an influence on the inner life of man may be beneficial for his health is a commonplace truth to-day for everybody. Every serious discussion of the question has to consider which influences are appropriate, and in which cases of illness the influence on inner life is advisable. The popular treatises usually start this chapter by speaking of the "mental and moral" factors; and this coupling of mental influences and moral influences characterizes large parts of the discussions of the Christian Scientists and the Christian half-scientists. Yet we must insist that the right entrance to psychotherapy is missed if the difference between morality and mentality is not clearly recognized from the beginning. The confusion of the two harms every statement. To avoid such a fundamental mistake, we had to take the long way around and to examine carefully what psychology really means and what it does not mean.