title: A beginner's psychology,
text: vV «5 v V ^ x° °X> ^^ i- oo' V- .\ \0 S - o <*, ^ ■ vV -/ ^ s* -\P C '' * A ,tf O, 'i ,0 o tf : "o0 ^ V* r ,' c» <^r. .\\> Nf, V \\' V s0 o, ^ ^ y *<> & +*. \ <* * <p. .-* <y ,'. H -7* N° ^ ,v t .0 o .# x ' " f o \y </> V* m> = \ c Digitized by the Internet Archive in 2011 with funding from The Library of Congress ^ fb^ %$ AS ,\* & % s , ""% < J A x % A* * **'•' http://www.archive.org/details/beginnerspsycholOOtitc N°°x. \ ^. ^ -3 i A BEGINNER'S PSYCHOLOGY THE MACMILLAN COMPANY NEW YORK • BOSTON -CHICAGO • DALLAS ATLANTA • SAN FRANCISCO MACMILLAN & CO., Limited LONDON ■ BOMBAY • CALCUTTA MELBOURNE THE MACMILLAN CO. OF CANADA, Ltd. TORONTO A BEGINNER'S PSYCHOLOGY BY EDWARD BRADFORD TITCHENER Wefo Iforfc THE MACMILLAN COMPANY 1915 All rights reserved -& t^\ V Copyright, 1915, By THE MACMILLAN COMPANY. Set up and electrotyped. Published December, 1915. Norfooorj $«B8 J. 8. Cushing- Co. — Berwick & Smith Co. Norwood, Mass., U.S.A. £/0-C DEC 2 t^ci.A414867 ^ THE MEMORY OF THOMAS HENRY HUXLEY PREFACE It is an acknowledged fact that we perceive errors in the work of others more readily than in our own. — Leonardo da Vinci In this Beginner's Psychology I have tried to write, as nearly as might be, the kind of book that I should have found useful when I was beginning my own study of psychology. That was nearly thirty years ago ; and I read Bain, and the Mills, and Spencer, and Rabier, and as much of Wundt as a struggling ac- quaintance with German would allow. Curiously enough, it was a paragraph in James Mill, most un- psychological of psychologists, that set me on the in- trospective track, — though many years had to pass before I properly understood what had put him off it. A book like this would have saved me a great deal of labour and vexation of spirit. Nowadays, of course, there are many introductions to psychology, and the beginner has a whole library of text-books to choose from. Still, they are of varying merit ; and, what is perhaps more important, their temperamental appeal is diverse. I do not find it easy to relate this new book to the older Primer, — which will not be further revised. There is change all through ; every paragraph has been rewritten. The greatest change is, however, a shift of attitude ; I now lay less stress than I did ; upon knowledge and more upon point of view. The beginner in any science is oppressed and sometimes viii Preface disheartened by the amount he has to learn ; so many- men have written, and so many are writing ; the books say such different things, and the magazine articles are so upsetting ! Enviable is the senior who can reply, when some scientific question is on the carpet, — There are three main views, A's and B's and C's, and you will find them here and there and otherwhere ! But as time goes by this erstwhile beginner comes to see that knowledge is, after all, a matter of time itself. If he keeps on working, knowledge is added unto him ; and not only knowledge, but also what is just as valuable as knowledge, the power of expert assimilation ; so that presently, when some special point is in debate, he is not ashamed of the plea of ignorance. He has learned that one man cannot compass the full range of a science, and he is assured that so-many hours of expert attention will make him master of the new matter. He comes in this way not, surely, to under- estimate knowledge, but to be less anxious about it; and as that preoccupation goes, the point of view seems to be more and more important. Why is it that be- ginners in science are so often disjointed in their think- ing, so often superficial, unable to correlate what they know, logically all at sea ? There is no doubt that they are, whether they study physics or chemistry, biology or psychology. I think the main reason is that they have never got the scientific point of view ; they are taught Physics or Biology, but not Science. Hence I have, in this book, written an inordinately long intro- duction, and have kept continually harping on the difference between fact and meaning. I try to make the reader see clearly what I take Science to be. Not that I offer this little essay as a model of clear thought ! The ideas of current psychology and the words in which they find expression are still, in very large measure, an affair of tradition and compromise ; and even if a writer has fought through to clarity, — past experience forbids me to hope that : but even if one had, — a book meant for beginners may not be too consistently radical ; some touch must be maintained with the past, and some too with the multifarious trends of the present. There is something turbid in the very atmosphere of an elementary psychology (is the air much clearer elsewhere ?), and it is difficult to see things in perspective. So the critic who will soon be saying that the ideal text-book of psychology has yet to be written will be heartily in the right, even if he is not particularly helpful. The present work has its due share of the mistakes and minor contradictions that are inevitable to a first writing ; at many points it falls short of my intention, — Voeuvre qiion porte en soi parait tonjours plus belle que celle qiton a faite; and I daresay that the intention itself is not within measure^ able distance of the ideal. It is, nevertheless, the best I can do at the time ; and it is also, I repeat, the kind of book that I should have liked to have when I began psychologising. x Preface Psychological text-books usually contain a chapter on the physiology of the central nervous system. The reader will find no such chapter here ; for I hold, and have always held, that the student should get his ele- mentary knowledge of neurology, not at second hand from the psychologist, but at first hand from the physi- ologist. I have added to every chapter a list of Ques- tions, looking partly to increase of knowledge, but especially to a test of the reader's understanding of what he has just read. I have also added a list of References for further reading. It depends upon the maturity and general mental habit of the student whether these references — made as they are, in many cases, to authors who do not agree either with one another or with the text of the book — should be followed -up at once, or only after the text itself has been digested. The decision must be left to the instructor. My own opinion is that beginners are best given one thing at a time, and that the knowledge- questions and the references should therefore, in the ordinary run of teaching, be postponed until some 'feeling' for psychology, some steadiness of psycho- logical attitude, has become apparent. I have avoided the term ' consciousness.' Experi- mental psychology made a serious effort to give it a scientific meaning ; but the attempt has failed ; the word is too slippery, and so is better discarded. The term ' introspection ' is, I have no doubt, travelling the same road ; and I could easily have avoided it, too ; but the time is, perhaps, not quite ripe. I have said nothing of the 'thought-element', which seems to me to be a psychological pretender, supported only by Preface xi the logicising tendencies of the day ; and if I am wrong no great harm has been done, since a description of this alleged elementary process, by positive characters, is not yet forthcoming. My references are confined to works available in the English language ; I think it un- likely that the students for whom this book is intended will have attained to any considerable knowledge of French or German. Lastly, — I believe that this is my last major omission, — I have referred only inci- dentally to the ' application ' of psychology ; for science is not technology, though history goes to show that any the least fact of science may, some day or other, find its sphere of practical usefulness. Two of my illustrations are borrowed : the swallow- figure on p. 138 from Professor Ebbinghaus, and the cut on p. 282 from Dr. A. A. Griinbaum. I am sorry to confess that a few of the quotations which head the chapters are mosaics, pieced together from different paragraphs of the original. Even great writers are, at times, more diffuse than one could wish ; or perhaps it would be fairer to say that they did not write with a view to chapter-headings. I hope, in any case, that no injustice has been done. It is a very pleasant duty to acknowledge the assist- ance that I have received from my Cornell colleagues, Prof. H. P. Weld and Drs. W. S. Foster and E. G. Boring, and from Dr. L. D. Boring of Wells College. I am indebted to all for many points of valid criticism, and I wish to express to all my sincere thanks for much self-sacrificing labour. I have retained the late Professor Huxley's name in xii Preface the forefront of this new primer, partly as an act of homage to the master in Science, — the brilliant in- vestigator, the fearless critic, the lucid expositor ; and partly, also, as a personal tribute to the man it was my earlier privilege to know. Cornell Heights, Ithaca, N.Y. July, 1915. CONTENTS CHAPTER I PSYCHOLOGY: WHAT IT IS AND WHAT IT DOES SECTION 1. Common Sense and Science. 2. The Subject-matter of Psychology 3. Mind and Body 4. The Problem of Psychology 5. The Method of Psychology 6. Process and Meaning 7. The Scope of Psychology 8. A Personal Word to the Reader Questions and Exercises. References for Further Reading PAGE 1 5 10 14 18 26 30 34 37 40 CHAPTER II SENSATION 9. Sensations from the Skin 43 10. Kinaesthetic Sensations 45 11. Taste  Organic Sensations .64 15. Sensation and Attribute ........ 65 16. The Intensity of Sensation . 67 Questions and Exercises ....... 70 References 72 CHAPTER III SIMPLE IMAGE AND FEELING 17. Simple Images . . .. 18. Simple Feelings and Sense-feelings Questions and Exercises. References. xiii 73 79 S7 88 xiv Contents CHAPTER IV ATTENTION SECTION PAGE 19. The Problem of Attention 90 20. The Development of Attention 93 21. The Nature of Attention 99 22. The Experimental Study of Attention 103 23. The Nervous Correlate of Attention 106 Questions and Exercises 110 References . . . Ill CHAPTER V PERCEPTION AND IDEA 24. The Problem in General 112 25. The Analysis of Perception and Idea 114 26. Meaning in Perception and Idea 117 27. The Types of Perception ....... 121 28. The Perception of Distance 125 29. The Problem in Detail . 131 30. The Types of Idea 138 Questions and Exercises ....... 142 References 143 CHAPTER VI ASSOCIATION 31. The Association of Ideas 145 32. Associative Tendencies : Material of Study .... 149 33. The Establishment of Associative Tendencies . . . 152 34. The Interference and Decay of Associative Tendencies . 156 35. The Connections of Mental Processes 159 36. The Law of Mental Connection 162 37. Practice, Habit, Fatigue . . 169 Questions and Exercises 174 References 176 CHAPTER VII MEMORY AND IMAGINATION 38. Recognition 177 39. Direct Apprehension] 181 Contents xv SECTION PAGE 40. The Memory-idea ... 184 41. Illusions of Recognition and Memory 187 42. The Pattern of Memory. 189 43. Mnemonics 192 44. The Idea of Imagination. 194 45. The Pattern of Imagination 197 Questions and Exercises. 201 References .... 202 CHAPTER VIII INSTINCT AND EMOTION 46. The Nature of Instinct 203 47. The Two Sides of Instinct .207 48. Determining Tendencies ....... 212 49. The Nature of Emotion 215 50. The James-Lange Theory of Emotion 218 51. The Expression of Emotion 222 52. Mood, Passion, Temperament 225 Questions and Exercises 228 References 229 CHAPTER IX ACTION 53. The Psychology of Action 230 54. The Typical Action 233 55. The Reaction Experiment 236 56. Sensory and Motor Reaction 239 57. The Degeneration of Action: From Impulsive to Reflex . 242 58. The Development of Action : From Impulsive to Selective and Volitional 246 59. The Compound Reaction . ... . . . 252 60. Will, Wish, and Desire ........ 255 Questions and Exercises 259 References . . . 260 CHAPTER X THOUGHT 61. The Nature of Thought 62. Imaginal Processes in Thought : The Abstract Idea 261 263 XVI Contents SECTION PAGE 63. Thought and Language 267 64. Mental Attitudes . ■ 271 65. The Pattern of Thought 275 66. Abstraction and Generalisation 280 67. Comparison and Discrimination 283 Questions and Exercises 287 References 288 CHAPTER XI SENTIMENT 68. The Nature of Sentiment 69. The Variety of Feeling-attitude 70. The Forms of Sentiment 71. The Situations and their Appeal 72. Mood, Passion, Temperament. Questions and Exercises. References 290 293 297 300 304 305 306 CHAPTER XII SELF AND CONSCIOUSNESS 73. The Concept of Self 74. The Persistence of the Self 75. The Self in Experience. 76. The Snares of Language 77. Consciousness and the Subconscious 78. Conclusion Questions and Exercises. References .... 307 312 315 321 323 328 332 334 APPENDIX DREAMING AND HYPNOSIS 79. Sleep and Dream 335 80. Hypnosis 341 - References 349 Index of Names 351 Index of Subjects 353 A BEGINNER'S PSYCHOLOGY A BEGINNER'S PSYCHOLOGY CHAPTER I Psychology : What it Is and What it Does It is well for a man, when he seeks a clear and unbiassed opinion upon some certain matter, to forget many things, and to begin to look at it as if he knew nothing at all before. — Li Hung Chang § i. Common Sense and Science. — We live in a world of values. We have material standards of com- fort, and moral standards of conduct ; and we eat and drink, and dress, and house our families, and educate our children, and carry on our business in life, with these standards more or less definitely before us. We approve good manners; we avoid extravagance and display ; we aim at efficiency ; we try to be honest ; we should like to be cultivated. Everywhere and always our ordinary living implies this reference to values, to better and worse, desirable and undesirable, vulgar and refined. And that is the same thing as saying that our ordinary living is not scientific. It is not either unscientific, in the regular meaning of that word ; it has nothing to do with science; it is non-scientific or extra-scientific. For science deals, not with values, but with facts. There is no good or bad, sick or well, useful or useless, in science. When the results of science are taken over into everyday life, they are transformed into values ; the telegraph becomes a business necessity, 2 Psychology: What it Is and What it Does the telephone a household convenience, the motor-car a means of recreation; the physician works to cure, the educator to fit for citizenship, the social reformer to correct abuses. Science itself, however, works simply to ascertain the truth, to discover the fact. Mr. H. G. Wells complains in a recent novel that no sick soul could find help or relief in a modern text-book of psychology. Of course not ! Psychology is the science of mind, not the source of mental comfort or improvement. A sick soul would not go, for that matter, to a text-book of theology; it would go to some proved and trusted friend, or to some wise and tender book written by one who had himself suffered. So a sick body would betake itself, not to the physiological laboratory, but to a physician's consulting room or to a hospital. We live, again, in a world whose centre is ourself. This does not necessarily mean that we are all selfish; a life may be very unselfish. But whether we are self- ish or unselfish, we live in a universe which revolves about the Me. Our self spreads and expands, to em- brace our clothes and house and books, our family and relations, our professional competence and connection, our political and religious beliefs; we find ourselves in all these things, and they become a part of us. A famine in India is a real event and takes its place in the world only if we are made uncomfortable when we read of it, or are stirred to send in a contribution, or suspect mismanagement somewhere and think we could have done better. And this, once more, is the same thing as saying that our ordinary living is not scientific. For science, which deals with facts, is on that account imper- § i. Common Sense and Science 3 sonal and disinterested. Men of science honour Dar- win, because they are human beings and live, like every- one else, in a world of values; but these same men of science are ready at any moment to test and criticise Darwin's work with the utmost rigour ; while any parts of the work that are solidly established pass without name into the structure of the science to which they belong. A text-book of chemistry is about as imper- sonal as anything can be, despite the fact that every observation it describes and every law it lays down was once somebody's personal observation or discovery, and so formed part of some self-centred universe. That personal interest is irrelevant to science. It is as irrelevant to psychology as to chemistry. The psy- chologist has a great deal to do with his own mind; but that is because his own mind is the most easily accessible part of his subject-matter; it is not in the least because the mind happens to be his own. This belief belongs to the non-scientific world ; those who 4 Psychology: What it Is and What it Does hold it fear that the psychologist will detect in them some pettiness or meanness of human nature, or will lay his finger on some unfounded enthusiasm or some unrea- soned detraction that they wish to conceal. As well might they think that the physicist whom they ask to dinner will be occupied with the surface-tension of his soup or the insulating properties of his mashed potato. If we trace the history of human thought, we find that the scientific attitude, as we have here described it, has emerged very slowly from that mixed medley of super- stition and knowledge and belief and practical interest for which we have no better name than common sense. How common sense has been constituted, and how science has gradually worked its way to an independent posi- tion, — these are interesting questions ; but it is plain that we cannot enter upon them in a primer of one special science. Some references for further reading will be given at the end of the chapter. Meanwhile, the important thing is to understand clearly the aims and limitations of science. Science aims at truth; it deals with facts, with the nature of things given, not with values or meanings or uses ; and it deals with these materials impersonally and disinterestedly. The student of science who fails to grasp the scientific point of view will fail also to get the perspective of a scientific text- book ; he will not see the wood for the trees ; and he will be disappointed with what science has to offer him ; he will want to know the use of all this knowledge, while science has no regard for use. The laws of psychology may be put to very many uses, in business, in education, in legal procedure, in medicine, in the ministrations of § 2. The Subject-matter of Psychology 5 religion ; but such uses are, from the psychologist's point of view, by-products of his science ; just as the nautical almanac is a by-product of astronomy, or the safety- match a by-product of chemistry, or the stamping-out of malaria a by-product of biology. These practical results may be immensely important for everyday life ; but science, in its impersonal and disinterested search for facts, makes no difference between one fact and another. § 2. The Subject-matter of Psychology. — Psychology is the science of mind. What, then, is mind ? Every- boSy 7 knows that, you will say, just as everybody knows what is matter. Everybody knows, yes, in terms of common sense; but we have seen that common sense is not science. Besides, common sense is not articulate ; it cannot readily express itself ; and it is a little afraid of plain statements. Close this book, now, and write down what you take mind to be; give yourself plenty of time ; when you have finished, go over what you have written, and ask yourself if you really know what all the words and phrases mean, if you can define them or stand an examination on them ; the exercise will be worth while. Open the book again ! The exercise was worth while ; but it was not quite fair. For the fact is that these great comprehensive words that we all use and all understand cannot be rigorously denned; they are too old ; they have lived through too many changes ; they have gathered about them too many conflicting asso- ciations. They pass muster in our everyday discourse 6 Psychology: What it Is and What it Does only because we take them for granted and do not scrutinise them too closely. The expert alone can say what common sense means by mind ; and even the expert must speak in general terms, qualifying and with reservations. It seems, however, that the prime factor in the com- mon-sense notion of mind is the idea of activity. We ascribe to mind the same sort of voluntary and pur- poseful activity that we ascribe to our fellow-men ; and we distinguish this activity from the blind necessity of cause and effect. We find ourselves, and those about us, deliberating, intending, resolving, planning, recalling, doubting; and we say that these and similar activities are activities of mind. We also find ourselves, and those about us, breathing, secreting, moving; but here we draw distinctions. Breathing, we say, is a physical affair, though we may hold the breath by an act of will. Secretion results from some physical or chemical cause ; only if we cry for sorrow or sweat for fear is mind influ- encing body. Walking and blinking may be physical only ; but if we turn our steps by intention into a cer- tain path, or blink on purpose to clear our sight, the physical movements become subject to the action of mind. So long as we stick to examples, all this seems straight- forward ; only it is not easy to decide whether mind is activity, or whether these various activities are activities of mind. On the whole, common sense leans to the latter view : the activities are manifestations of mind. Mind itself is then something immaterial, lying behind the manifestations. What sort of thing? Apparently, § 2. The Subject-matter of Psychology 7 another human being, an inner man that dwells within the outer man, an insubstantial mannikin living inside the head. Does that sound absurd? But it did not seem absurd just now to read that we ascribe to mind the same sort of voluntary and purposeful activity that we ascribe to our fellow-men ; and how could we do that unless mind were something like a human being? This inner man appears, in fact, to be the mind of common sense ; the inner man thinks, reflects, remembers, de- sires; he is influenced by the outer man, becoming gloomy and morose when his host cannot digest; and he influences the outer man, who sheds tears when his inmate is grieved. A curious view, when we write it out and think of it in cold logic; but a view that we should understand if we traced the growth of common sense from its first beginnings ; and a view of highly respectable antiquity. Very ancient superstitions are connected with the man who is seen in the eye; the Egyptian ka or spirit-double is a smaller copy of the outer man ; Greek vase-paintings show the human soul as a tiny human being; primitive thought has from time immemorial explained, and the modern savage still explains, the life and motion of man, or his repose in sleep and death, by the presence or absence of the little creature normally at work within him. Yet however natural a view like this may be, science can make nothing of it. For one thing, it merely pushes the problem a step further back. The inner man acts on the outer man and is acted on by him ; but who or what gives the inner man, in his turn, the power to influence and to be influenced? We must suppose ) 8 Psychology: What it Is and What it Does an endless nest of mannikins. That and other such arguments apart, however, the view is non-scientific be- cause it offers an interpretation and not a description of mind. The mind with which psychology deals must be a mind that is describable in terms of observed fact; otherwise it cannot form the subject-matter of a science. So we must start afresh, and ask what mind is, when mind is looked at from the scientific point of view. You will better understand the answer to this question when you have worked through the book. The answer will then have been given in the concrete and particular ; now it can be given only in the abstract and general. Remember that it is given, nevertheless, in terms of work done and results obtained; it is not an answer that the psychologist makes up beforehand, but one that he himself has been led to in the course of his attempt to work scientifically upon mind. In brief it is this. We find that the field of science has been surveyed from two different standpoints. Men of science have set out, on the one hand, to describe the world as it would be with man left out. The result is what we call physical science. The world of physics is colourless, toneless, neither cold nor warm; its spaces are always of the same extent, its times are always of the same duration, its mass is invariable ; it would be just what it is now if mankind were swept from . the face of the earth. For what is light in the text-books of physics? — a train of electromagnetic waves ; and sound is a vibratory motion of air or water ; and heat is a dance of molecules ; and all these things are independent of man. But men of science have tried, on the other § 2. The Subject-matter of Psychology 9 hand, to describe the world as it is in man's experience, as it appears with man left in; and the result of this endeavour is psychology. The world of psychology contains looks and tones and feels; it is the world of dark and light, of noise and silence, of rough and smooth ; its space is sometimes large and sometimes small, as everyone knows who in adult life has gone back to his childhood's home ; its time is sometimes short and some- times long; it has no invariables. It contains also the thoughts, emotions, memories, imaginations, volitions that you naturally ascribe to mind ; it contains, that is, so much of these things as belongs to the sphere of observ- able fact. It is obviously very different from the world of physics, though both worlds alike have been opened up to us by science, by the impersonal and disinterested search for facts. So we have a world of matter and a world of mind. The physicist, however, describes and measures the various phases of energy, without assuming any ma- terial substance in the background, any matter of which this energy is the manifestation. Matter, if the word is to be used at all, is simply the inclusive name for all the forms of energy. And the psychologist, in the same way, describes and measures — so far as he is able to measure — the phenomena of his world, without assum- ing any active or perduring mind in the background ; for him, mind is simply the inclusive name of all these phenomena. That is the first rough answer to our ' question. Much more must be said, if the answer is to be precise ; but even as it is we have travelled a long way from the little man living inside the head ! 10 Psychology: What it Is and What it Does § 3. Mind and Body. — The first thing to get clear about is the nature of the man left in the world, the man whose presence is necessary for psychology and unneces- sary for physics. Since we are talking science, this man will be man as science views him, and not the man of common sense ; he will be, that is, the organism known to biology as homo sapiens, and not the self-centred person whom we meet in the everyday world of values. But the human organism owes its organic character, the organisation of its parts into a single whole, to its ner- vous system. All over the body and all through the body are dotted sense-organs, which take up physical and chemical impressions from their surroundings ; these impressions are transmitted along nerve-fibres to the brain ; in the brain they are grouped, arranged, supplemented, arrested, modified in all sorts of ways; and finally, it may be after radical transformation in the brain, they issue along other nerve-fibres to the muscles and glands. The nervous system thus receives, elabo- rates, and emits. Moreover, there is strong evidence to show that the world which psychology explores depends for its existence upon the functioning of the nervous system ; or, if we prefer a stricter formula, that this world is correlated with the functioning of the nervous system. The man left in thus reduces to a ner- vous system ; and that is the truth of the statement, often met with in popular scientific writing, that the brain is the organ of mind. There is no organ of mind ; that phrase is an echo of the old-world search after the place of residence of the mannikin-mind, which was assigned variously to heart, liver, eye, brain, blood, or § 3- Mind and Body n was supposed somehow to perfuse the whole body. The scientific fact is that, whenever we come upon mental phenomena, then we also find a functional ner- vous system ; we know nothing of the former apart from the latter ; the two orders are thus correlated. The fact of this correlation has been established by two principal lines of evidence. In the first place, we find all through the animal kingdom that size of brain and complexity of nervous system are matched by range and complexity of mental phenomena. The brain of man is, by absolute measurement, an organ of great size ; it is heavier than that of any other animal with the ex- ception of a few of the very largest (such as the elephant) ; and in these cases the superior weight is due, not to su- perior development of the elaborating part of the brain, but to the bulk of the receiving and emitting portions, which are of a size to correspond with the bulk of the body. The brain of man is also relatively, as compared with the weight of the whole body, heavier than the brain of any other animal with the exception of a few of the most highly developed small mammals (such as certain monkeys) ; and in these cases again the superi- ority depends on the bulk of the receiving and emitting portions of the brain, which reflect the keen sensitivity and muscular agility of the animal. We know, on the other side, that the mental life of man is richer than that of any other creature. Secondly, we find that dis- turbance of certain parts of the brain indicates a certain form of mental disturbance; and, conversely, that partic- ular forms of mental disturbance indicate disturbance of particular parts of the brain. One may become blind 12 Psychology: What it Is and What it Does from injury to the brain as well as from such defect of the eye as prevents optical impressions from reaching the brain. These are the two lines of evidence. How, though, you may now ask, do we know anything about the dis- tribution of mental phenomena in the animal kingdom? How do we know that the lower animals live in mental worlds? and still more how can we say anything as to the nature of the phenomena that make up those worlds ? Consider first the case of your fellow-men. You do not doubt that they have experiences like your own ; you take them for granted, accept them instinctively as your kin, and are able — the better as you know them better — to put yourself in their place. If, however, you had to argue the matter with a sceptic, you would point to the facts of our common life. Man's family life, social life, civic life, national life, is based on the as- sumption that human experience is alike for everyone, and would be impossible if the assumption were falsi- fied by the facts. All these forms of life, for instance, presuppose language and laws ; and language and laws necessarily imply a community of experience. You would point, also, to likeness of physical organisation, likeness of sense-organs and nervous system; and you would point, lastly, to conduct or behaviour. When you feel in a certain way, you act in a certain way; your behaviour expresses your feeling; and when, under the same circumstances, a creature of like organisation reg- ularly acts in the same way, you have a right to infer that this creature has a like feeling. Now consider the higher animals. They possess a § 3- Mind and Body 13 physical organisation closely resembling that of man. They also behave in ways that appear to express feel- ing. If you were familiar only with their structure, with their sense-organs and nervous system, you would be ready to endow them with mind ; if you knew them only by their behaviour, you would reach the same con- clusion ; since you may know both, and may therefore correlate physical structure with conduct, you are able to form a fairly accurate idea of their mental world. But as you go down the scale of life, difficulties arise. The nervous system changes its type, and presently disappears ; and behaviour becomes equivocal, so that students of behaviour dispute whether it is still expres- sive or is purely mechanical. The controversy is even carried over from the animals to the plants ; there are psychologists who seriously attribute a mental life to plants. Be that as it may, the important point for us is that, as the nervous system simplifies, so does all available evidence indicate that the world of mind sim- plifies with it; and if mind extends further down the line of life than the nervous system, we have merely to change the wording of our general statement; we must expand it, and say that, throughout the realm of life, size and complexity of the nervous system, or of that vital mechanism which precedes the nervous system and anticipates its functions, are matched by range and complexity of mental phenomena. The nature of these phenomena cannot be set forth with any assurance. It is difficult enough to psychologise the life of the Australian Arunta, who is our fellow-man, or of the dog who has been our companion for half-a- 14 Psychology: What it Is and What it Does dozen years. What shall we say of the spider, or the amoeba, or of sundew and eelgrass? All that we can do is to follow back the history of the sense-organs, from complex to simple, comparing as we go ; and to observe how the organism behaves under given circumstances, comparing this behaviour with that of other organisms higher and lower in the scale, and bringing our compari- son back again and again to its final term in our own experience. We lose a great deal when we lose the ner- vous system ; but life, after all, is a continuous develop- ment; and the disappearance of this special structure, though it may mean that our statements become vaguer and less definite, need not make our general quest hope- less. Honesty of purpose, and a passion for knowledge, and sound scientific training will carry a man further, even in this dark continent, than the casual enquirer would deem possible. § 4. The Problem of Psychology. — The subject- matter of psychology, as we saw on p. 9, is the whole world as it shows itself to a scientific scrutiny with man left in. Or, to put the same thing in another way, psy- chology gives a scientific description of the whole range of human experience correlated with the function of the human nervous system. We have just learned, however, that there is a psychology of the lower animals, possibly even of plants; and we must therefore say that we were speaking in § 2 of the subject-matter of human psychology. This is the psychology that will occupy us in the present book. Let us now see what our actual task is. What have we to do, in order to get a scientific description of mind ? § 4- The Problem of Psychology 15 We must do what everybody does who begins to describe ; we must take things piecemeal. When you are away at the seaside, and are describing your room in a letter home, you tell of exposure and windows and carpets and furniture and pictures ; you break up the room into parts, and list them one by one; but you do not list at haphazard ; you bring your items into such connection as will make it easy for your readers to re- construct the room. The man of science does the same sort of thing ; he analyses, and all the while he is ana- lysing he has his eyes open for relations, for putting his elements together again as they belong. The chemist analyses water into oxygen and hydrogen, and acetic acid into carbon, oxygen, and hydrogen ; and you see at once that this analysis is the first step toward a scientific description ; for it reduces the compounds to their elementary components, and it shows that the two compounds have certain elements in common. But the chemist, almost in the same breath, is putting together again. The ordinary formulas for water and acetic acid, H 2 and C2H4O2, indicate that; for they show the number of atoms of the various elements that are held in the compound. Chemistry also has graphic formulas, of a kind that look complicated to the out- sider but that are really more instructive than the others, — formulas which show in what manner, under what laws, the atoms are bound together. Any good ency- clopaedia will give you samples. The psychologist, now, stands before a like problem. The mental world, no less than the material, comes to us in the gross ; mental phenomena are complex, often 1 6 Psychology : What it Is and What it Does highly complex ; we must reduce them to their elements, we must keep analysing till we can analyse no further, if we are to describe them in a scientific way. And here too synthesis goes hand in hand with analysis. Psy- chology, to be sure, does not write graphic formulas ; but psychology has to show how its elements go to- gether, to discover the laws of their connection; we shall find that tones and colours go together in very dif- ferent ways. All the while that we are tearing a bit of our world apart, and finding its elements, we are try- ing to put those elements back again in their places and to reconstruct the original experience. Synthesis, unfortunately, is often very difficult; and you must notice that a, failure to reconstruct does not necessarily mean that the preceding analysis was wrong. A chemist may analyse a given substance into a certain number of elements, each one represented by a certain number of atoms ; yet if he puts these elements together again, in the right proportions, he may — perhaps be- cause he is now working at a different temperature — ■ come out with another substance of different proper- ties. His analysis was not therefore wrong; but his attempt at synthesis is a failure because he has not taken account of all the relevant circumstances. It may happen similarly in psychology that we do not know all the relevant circumstances ; or it may happen that we know them but cannot control them ; in such cases we cannot reconstruct. The only thing to do is then to make analysis its own test ; we analyse again and again ; and if the result is always the same, we are satisfied to let it stand. Children who do not know how to prove § 4- The Problem of Psychology 17 an example in arithmetic follow the same plan ; if they get the same answer several times over, and if their schoolmate gets that answer too, they are satisfied ; and when the work has been honestly done, the agree- ment is pretty good evidence that they are right. Notice one other point : that if you sit down to de- scribe, there is simply no escape from analysis. To begin a description is to be analysing. Well-meaning people sometimes shake their heads at scientific psychology; all this dissecting work, they say, misses the real issue ; it kills mind; it destroys the living, breathing reality of experience, and offers in its place a catalogue of dead facts. The mannikin again ! Of course, if mind is a little man inside you, you must kill him to dissect him, — though he nevertheless crops up again, alive and well, after the autopsy. The mannikin, as we have seen, cannot face cold logic. No, the task of science is to describe ; if you are to describe you must analyse ; and the results are every bit as real as the unanalysed expe- rience. Dead facts? But a fact is the most live thing possible ; it will survive any number of theories, and will still give birth to more. 