The foundations of psychology

Front matter

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Preface

The present volume is designed to serve a twofold purpose — (i) as a textbook in advanced courses in general psychology, and (2) for general reading on the subject of the nature and methods of mental science. The work contains matter not usually found in the ordinary brief textbooks and manuals of psychology, and yet it is the endeavor of the author to present his material in such a form that it may be grasped by any interested reader who is familiar with those facts of the science which may be found recorded in any good textbook.

The only work in English which in any degree covers the ground that I myself have traversed is the book by Boris Sidis on The Foundations of Normal and Abnormal Psychology. But though reference is frequently made in the following pages to this valuable work, a comparison of the tables of contents of Dr. Sidis's book and my own will be sufficient to indicate our differences in plan and aim.

Another writer frequently cited in the ensuing pages is Hugo Miinsterberg, and I wish to record here my deep sense of indebtedness to him for his illuminating work on the great problems of philosophy and of natural and mental science. This indebtedness is manifested many times in the ensuing work, notwithstanding my differences with him on many points. I think it may truthfully be said that in his death America has lost its one great theoretical psychologist — and in so writing, I say nothing of his invaluable work as a pioneer in the fields of practical and applied psychology.

All quotations are in the exact words of the original writers, though I have not hesitated to change the marks of punctuation when such change has seemed to be in the interests of clearness. Words in square brackets [ ] have been added by the author of this book.

Vii viii PREFACE

Sections are numbered consecutively throughout the book, regardless of chapters, and numbers in parenthesis in the text refer always to those numbered sections. Chapters also are numbered consecutively, regardless of the larger "Books/' Most of the chapters are broken up into "Divisions," the numbering of which starts anew in each successive chapter.

I wish to acknowledge with gratitude the assistance of my wife in the preparation of the manuscript, and of my fatherin-law, Mr. D. W. Linch, in the drawing of some of the cuts; and also the interest of my colleagues, Professor M. M. Curtis and Professor H. A. Aikins.

Table Of Contents

Preface vii

Bibliography xvii

Introduction i

Book II The Field Of Scientific Psychology

IV. Psychology and Metaphysics 89

49. The Problem of the Basis of a Scientific Psy-

chology 89 xii TABLE OF CONTENTS

1. The Problem of Science 89

50. The General Problem of Science. 89

51. Scientific Description 90

52. Scientific Explanation 91

53. The Concept of Causation 91

54. The Nature and Kinds of Scientific Hypothe-

ses 92

55. The Validity of Conceptual Hypotheses 94

56. Is Science purely Descriptive? 95

Table V. Stages of the Scientific

Method 97

2. The Problem of Metaphysics, and its Re-

lation TO Science 97

57. The General Problem of Metapsyhics 97

58. The Artificiality of Science 98

59. Psychology and Meanings 100

60. Must Metaphysics be Rejected? 105

J. Psychology as Science and as Metaphysics 106

61. Aspects of Personality 106

62. Psychology vs. Metaphysics 108

63. Corresponding Attitudes toward Nature 109

4. Psychology and Real Life iii

64. Psychology and the True Personality ... ill

65. Physical Science and the Real World. . 113

66. The Necessity of a Scientific Study of the

Mind 115

6y. The Place of the Contemporary Schools of

Psychology 117

5. Psychology and Other "Mental Sciences" 117

68. The Mental Sciences and the Fine Arts 117

69. The Classification of the Sciences 120

Table VI. The Classification of the

Sciences 121

70. Psychology and Religion 122

TABLE OF CONTENTS xiii

V. Psychology and the Material Sciences 125

J. Theories of their Differentiation 125

71. The Problem 125

72. The Inner Sense Theory 125

73. The Immediate Experience Theory 127

74. Criticism and Conclusions 129

2. The Differentiation of Mental from Material Facts 132

75. The Non-Spatial Character of Mental Objects 132

76. Consciousness as Potential Energy 134

yy. The Privacy of Mental Facts vs. the Community of Physical Facts 138

78. Sidis's Doctrine of Mental vs. Physical 142

79. Various Secondary Characteristics of Mental

Phenomena 146

80. The Interpretation of the Mental-Physical

Distinction 148

81. Conclusion 149

J. Conditions of Psychological Description. . . 150

82. General Conditions of a Scientific Psychology 150

83. Munsterberg*s Theory 150

84. Criticism of Miinsterberg's Doctrine 152

Book III The Postulates Of Psychology

VI. The Postulates in General 159

1. The Statement OF THE Postulates 159

85. The Postulates 159

Table VII. Summary of the Postulates 162

2. The Principle of Psychocerebral Parallel-

ism 163

86. Psychophysical and Psychocerebral Parallelism 163 Note on the Principle of Independence. 166 xiv TABLE OF CONTENTS

J. The Principle of Independent Psychical

Causation i68

a. The Problem of Psychological Explanation. ... i68

87. The Problem 168

b. The Difficulties of Independent Psychical Causa-

tion 169

88. The Laws of Psychology 169

89. Causation in the Physical and Mental Realms 170

c. The Cerebral Theory of Psychical Causation. . . 174

90. The Cerebral Theory 174

91. Criticism of the Cerebral Theory 176

d. Defence of the Independence Theory 178

92. Methods of Explanation in Psychology 178

Table VIIL Theories of Psychological

Explanation 179

93. The Difficulties of Independent Psychical

Causation 180

94. The Problem of Sensations 181

95. The Problem of the Discontinuity of Mental

Life 184

Table IX. Difficulties in Accepting the Principle of Independent Psychical Causation, and How they may be Met 185

e. The Doctrine of Chance in Psychology ........ 185

96. Sidis's Doctrine of Chance in Mental Life. .. . 185

97. Criticism of the Doctrine of Chance in Psy-

chology 186

Vll. The Subconscious 189

1. The Concept of the Subconscious 189

98. Meaning of the Term 189

99. The Place of the Concept in Modern Psychol-

ogy 189

100. The Grounds for Postulating the Subconscious 190

2. Evidences of the Subconscious 192

TABLE OF CONTENTS xv

loi. Phenomena involving Personal Continuity. . . 192

102. Phenomena having no Conscious Causes.... 195

103. Phenomena apparently involving Intelligence. 197

J. Dissociation and the Coconscious 198

104. Meaning of the Terms 198

105. Examples of Dissociation 200

VIII. Theories of the Subconscious 202

1. Types of Theory 202

106. The Main Problem 202

107. The Dual Mind Theory 203

108. The Ultra-Marginal View of the Subconscious 204

109. The Subconscious as the Subliminal 207

2. Criticisms of the Concept of the Subcon-

scious 208

no. The Subconscious and its Critics 208

111. The Subconscious as Self -Contradictory 209

1 12. The Subconscious as Futile 211

113. The Subconscious as Gratuitous 211

J. The Theory of Unconscious Cerebration. . . 215

114. The Cerebral Explanation of the So-called

conscious Phenomena 215

115. Criticism of the Theory of Unconscious Cere-

bration 217

116. Consciousness and Content 219

4. Recent Developments in the Theory of the

Subconscious 220

117. Freud and Prince 220

118. Freud's Theory of the Subconscious 220

119. Prince's Theory of the Subconscious 221

120. Comparison and Suggested Modification of

Freud's and Prince's Theories 222

Table X. Classification of Psychical States, etc 224 xvi TABLE OF CONTENTS

5. Conclusions 225

121. Principles of Psychological Explanation 225

122. The Explanation of Memory 226

123. Explanation of the Varieties of the Subcon-

scious 228

124. Sidis's Criticism of the Doctrine of the Un-

conscious 230

BIBLIOGRAPHY

Following is an alphabetical list of all the books (not periodicals) which are cited in the reference lists at the close of the several chapters, arranged according to authors.

Calkins, Mary Whiton—

An Introduction to Psychology (Macmillan: 1901). A First Book in Psychology (Macmillan: Fourth Edition, 1914).

CORIAT, ISADOR H.

Abnormal Psychology (Moffat, Yard & Co.: Second Edition, 19 14).

DuNLAP, Knight —

A System of Psychology (Scribners: 1912). Freud, Sigmund —

The Interpretation of Dreams (trans, by A. A. Brill. Macmillan: 1913).

Galloway, George —

The Philosophy of Religion (Scribners: 1914). Hart, Bernard —

The Psychology of Insanity (Cambridge University Press: 1912).

Hoffman, Frank Sargent —

The Sphere of Science (Putnams: 1898).

Holt, Edwin Bissell —

The Freudian Wish, and its Place in Ethics (Henry Holt & Co.: 1915).

James, William —

Principles of Psychology (Henry Holt & Co.: 1890). Psychology, Briefer Course (Henry Holt & Co. : 1892). The Varieties of Religious Experience (Longmans, Green, & Co. : 1902).

Jastrow, Joseph —

The Subconscious (Houghton, Mifflin & Co.: 1906). Klemm, Otto —

A History of Psychology (trans, by E. C. Wilm and R. Pintner. Scribners: 1914). xvii xviii BIBLIOGRAPHY

Meyer, Max Friedrich —

The Fundamental Laws of Humam, Behavior (Richard G. Badger, Boston: 191 1).

More, Louis Trenchard —

The Limitations of Science (Henry Holt & Co.: 1915). Munsterberg, Hugo —

Psychology and Life (Houghton, Mifflin & Co. : 1899).

Science and Idealism. (Do. : 1906).

The Eternal Values (Do.: 1909).

Psychotherapy (Moffat, Yard & Co.: 1909).

Psychology General and Applied (Appletons: 191 4). Myers, Frederic W. H. —

Human Personality, and its Survival of Bodily Death (Two vols. Longmans, Green & Co.: 1903.

Abridged Edition, i vol., 1907).

Parmelee, Maurice —

The Science of Human B ehavior ( Macmillan : 1 9 1 3 ) . Paton, Stewart —

Human Behavior (Scribners: 1921).

Pearson, Karl —

The Grammar of Science (Third Edition, Vol., I. London, A. & C. Black: 1911).

Prince, Morton —

The Unconscious (Macmillan: 191 4).

ROYCE, JosiAH —

Studies of Good and Evil (Appletons: 1898).

Outlines of Psychology (Macmillan: 1903). Scripture, E. W. —

The New Psychology (Scribners: 1898).

Sellars, Roy Wood —

The Foundations of Normal and Abnormal Psychology (Richard G. Badger, Boston: 1914).

Titchener, Edward Bradford —

A Textbook of Psychology (Macmillan: 1910).

A Beginner's Psychology (Macmillan: 1915). Villa, Guido —

Contew^porary Psychology (Macmillan: 1903). Ward, James —

Psychological Principles (Cambridge University Press: 1918).

BIBLIOGRAPHY xix

Watson, John Broadus —

Behavior: An Introduction to Comparative Psychology

(Henry Holt & Co.: 1914).

Psychology from the Standpoint of a Behaviorist (Lippincott: 191 9).

Wells, Frederic LymaN' —

Mental Adjustments (Appletons: 191 7).

WUNDT, WiLHELM

Outlines of Psychology (trans, by C. H. Judd. Third Revised English Edition. Leipzig and New York, 1907).

Yerkes, Robert Mearns —

Introduction to Psychology (Henry Holt & Co. : 191 1).

Essays, Philosophical and Psychological, in Honor of William

James (Longmans, Green & Co. : 1908).

Studies in Philosophy and Psychology, by former students of

Edward Garman (Houghton, Mifflin & Co.: 1906). Subconscious Phenomena, by various authors (Richard G.

Badger, Boston: 1910).

Introduction

"There are periods in the growth of science when it is well to turn our attention from its imposing superstructure and to carefully examine its foundations." With these words Karl Pearson opened the preface to the first edition of his Grammar of Science, and they are fitting words with which to introduce our present study also. This is an age of great development in all fields of scientific investigation, and in no field more strikingly than in that of psychology. But although there are many builders of foundations — such men as Pearson, More, Enriques, Mivart, Poincare — it is chiefly the physical and biological sciences in whose bases they are interested, and rarely are the separate claims of psychology given their just due, if indeed they are considered at all.

Nor are the psychologists themselves altogether free from blame in this matter. Justly proud of the freedom which their science now enjoys — liberated comparatively late in time as it was from the shackles of metaphysical speculation, and resting securely upon the hard rock of empirical fact — they are giving their time and attention almost entirely to the development of the experimental method and the discovery of individual facts by its means, to the serious neglect of the broader significance of these facts. I do not mean to imply that there is no interest among psychologists in the foundation principles of their science, but I do mean that the interest is relatively slight, and that what work is being done in this field is grievously lacking in unity either of aim or of result. We find, in other words, not one science of psychology but many — structuralist psychologies, functionalist psychologies, behaviorist psychologies and others, each one claiming to be the truly scientific psychology, but having aims and ideals inharmonious with all the rest. Experimentation goes merrily on, building up a truly "imposing superstructure" where a half-century ago was nothing at all, but instead of one foundation fitly joining all the parts a number of distinct and mutually destructive foundations. What psychology needs most of all today is not so much more superstructure as a stronger foundation, not so much an analytic examination of facts as a synthetic view of the entire field.

It is for the purpose of at least securing a synthetic glimpse if not a complete view of this field that the present work has been undertaken. The situation and problem are these : First, as to the situation, psychology is today undoubtedly an empirical, inductive, observational, experimental, positive and concrete science. It is no longer a branch of philosophy, nor is it necessarily any more closely affiliated with philosophy than are any of the physical or biological sciences; for all sciences, non-psychological as well as psychological, must have a philosophical foundation. But at this point arises the problem: is psychology also a distinct science among its sister sciences? Is it, or can it become, as independent of physiology, of neurology, of biology, as it is of philosophy? Is the introspective study of the mind scientific psychology, or is the latter term applicable only to the experimental study of behavior? Certainly the tendency today is strongly toward the second of these alternatives, but as over against this tendency it is the underlying purpose of this book to defend the thesis that scientific psychology is independent alike of metaphysics on the one hand and of the biological sciences on the other, that there can be a complete science of psychology on this independent basis, and that introspection is really scientific and the distinctive method of scientific psychology; and to undertake the task of establishing some of the essential principles upon which such a complete and independent science of psychology must and may be built up.

The work will be divided into three parts; discussing (i) the various definitions or conceptions of psychology which

INTRODUCTION 3

have been suggested in the past and are being expounded today, with the aim of drawing a synthetic and positive conclusion as to the merits of these various conceptions; (2) the field of scientific psychology, its distinctiveness from metaphysics on the one hand and from physical and biological sciences on the other; and (3) the postulates necessary for the construction of a scientific psychology, with especial attention to the problems of parallelism, psychical causation, and the subconscious. And in closing these introductory remarks I again emphasize the fact that my aim is primarily not critical but constructive, and not constructive in the sense of seeking to build a new foundation for psychology but of synthetizing the foundations upon which the science is even now built. For the chief need of psychology today, and of philosophy too, is by no means the establishment of new schools, but the synthesis of the diverse but perfectly harmonizable truths that the great thinkers of the past have contributed to the treasury of present day knowledge.

CHAPTER I Historic Concepts of Psychology

I. The Two Most General Concepts of Psychology.

1. Since the beginning of man's interest in the study of his own mental life that interest has taken a twofold form, one metaphysical and the other scientific. The metaphysical interest, springing primarily from the religious needs of man, the hope of immortality and the belief in a soul life surviving the death of the body, gradually takes the form of what we know later as Rational'^ psychology: the scientific interest, arising out of man's intellectual nature, fulfilled in a truly scientific procedure, takes the form of what has long been known as EmpiricaP- psychology. These, then, are the two most general concepts — conceptions or ideals — of what psychology is and means, that have appeared in the history of that branch of human knowledge.

2. Rational Psychology has for its problem the nature, origin, and destiny of the soul. As such it is a branch of philosophy, and not strictly speaking a science at all.^ Philosophy has among its various problems that of the general nature of reality, the part of philosophy which studies this problem being metaphysics. As the soul, if it exists at all, is one of the

iThe use of these terms comes from the old antithesis in the theory of knowledge between reason and experience, "empirical" being the adjective corresponding to the noun "experience." However, the words have a well-established meaning, and that which we term "empirical psychology," as will soon appear, has by no means always been "scientific": hence it is better to retain the terms chosen than to reject them for no better reason than their merely etymological ambiguity.

2 The significance of this distinction, which is a distinction of the first importance, will appear later (v. especially, Chap. IV).

most important of all realities, rational psychology, which has the soul for its subject-matter, is one of the chief divisions of metaphysics. All the individual truths about the soul or mental life which rational psychology derives, therefore, are deduced from the general concept or definition of what the soul itself is.

3. Empirical Psychology, on the contrary, is interested in the facts of mental life just as they appear in our experience for their own sake, without inquiring into the real inner nature of the soul, or even caring whether there is such a reality as a soul. Rational psychology asks what mind or soul is, empirical psychology asks what the mind does or how it acts. Hence, the latter usually discards the word "soul" altogether, substituting for it such terms as "mind," "self," or "consciousness." It has come, therefore, in recent years to be spoken of, by its adherents proudly and by its critics reproachfully, as a "psychology without a soul." This designation serves clearly to mark off the empirical from the metaphysical type of psychology, and at the same time to emphasize the fact that empirical psychology is by its very nature incomplete and one-sided, and by no means, as its devotees too often claim, the last word on the subject of mental life. It also warns us not to allow ourselves to imagine for one moment that because rational psychology is older than empirical, and empirical psychology alone fashionable today, the problems and methods of metaphysics are therefore no longer of any importance. There is as valuable a place for metaphysical psychology in the world of thought today as there ever was, and there always will be such a place. This point, however, must be postponed until a later period in our investigations.^

2. The Schools of Rational Psychology.^

4. The schools of rational psychology are distinguished primarily according to their conception of the nature of the

3 V. Chap. IV.

* Cf., throughout this chapter, Table I, on p. 21.

mind: hence a classification of them is rather a classification of theories of mind than of concepts of psychology. On the question of the nature of the soul there have always been two schools in rational psychology — spiritualism and materialism; and on the question of the degree of relationship between the soul and the body, two — dualism and monism. Spiritiialism in psychology is the doctrine that all the phenomena of mental life are manifestations of a non-material soul, materialisfn in psychology is the theory that all psychical processes are modes or manifestations of matter. According to the dualistic conception, mind and matter are two sharply opposed substances: according to the monistic conception, mind and matter are in some way identified, as different manifestations of one form of reality. It follows from these definitions that dualism if consistent must necessarily be spiritualistic in its theory of the soul, but that monism may be either spiritualistic or materialistic according as this "one form of reality" is regarded as primarily spiritual or material in nature. There are, then, ultimately but three distinct schools of rational psychology — Dualism, Spiritualistic Monism, and Materialism, Dualism is the original school, the two forms of monism arising out of the necessity for resolving the inevitable difficulties of the dualistic position.

5. Dualism. — The dualistic view of human nature appears early in the history of the race, the experiences of dreams and of the permanent sleep we call death naturally leading to the conviction that man has a soul which, though bound up with the body during the waking hours, wanders freely out of the body in sleep, and at the time of death becomes separated from that body forever. Primitive conceptions of the soul are, indeed, crude and in many ways materialistic, the "soul" being thought of as little more than a detachable shadow of the body ; but as time goes on the concept becomes more and more spiritualized, until in the systems of Plato and Aristotle we have a purely idealistic notion of what constitutes the essential element of human nature. According to Aristotle, howlo THE FOUNDATIONS OF PSYCHOLOGY

ever, the soul is not so much an outside principle separate from the body, but rather is identified with the vital principle which dwells in and energizes the body. The psychology of Scholasticism continues this notion of immanent dimHsm, as we may call it, and it is not until the time of Descartes ( 1 596- 1650) that the dualistic conception reaches its logical climax in the transcendent view that the soul is a substance entirely distinct from the body and interacting with it from outside.

6. Monism. — It is this problem of interaction and the difficulty of explaining it that have led to the formulation of the monistic theory that mind and matter are not distinct realities, but different manifestations of one fundamental reality. Just as the dualistic theory of the universe is in its primitive form materialistic in its concept of the soul, but can become consistent only when the latter concept has been spiritualized; so the monistic theory of the universe as we first find it in Spinoza ( 1 632-1 677) is a neutral type of monism, the universe being regarded as fundamentally neither spiritual nor material, but such a general monistic metaphysics inevitably involves either a spiritualistic or a materialistic psychology — whatever the universe at large may be, the soul must be either material or non-material.

Dualism being necessarily spiritualistic, spiritualistic monism is the natural heir of the older, and by Spinoza and his adherents discarded, view of the soul. As representatives of this concept after Spinoza we may name especially Leibniz, Berkeley, Kant and his followers, and Lotze. In reaction against this view is the opposing doctrine of materialism, traceable to its origin in the Greek philosopher Democritus, and finding modern representatives of quite different types in Hobbes, Diderot, Moleschott, Biichner, Haeckel, and others.

7. But it would take us too far afield to dwell upon the distinction and relationship between the various schools of rational psychology, or to so much as hint at a comparison and criticism of them. Such a task belongs to the philosopher, and not to the psychologist in the current sense of that word.

THE DEFINITION OF PSYCHOLOGY ii

But it is well to be familiar with the meanings of these philosophical concepts, not only because this makes the far different problems of empirical psychology stand out all the more clearly by contrast, but also because those philosophical problems still exist and still cry for solution. I repeat that empirical psychology has not superseded rational psychology, but has merely added itself to the latter. Today the term "psychology" when used by itself always, and rightly, means empirical or scientific psychology; and the term "rational psychology" is nowadays little favored, the broader term "metaphysics," of which rational psychology is one branch, doing service for the parts as well as the whole, because of the inextricable interrelation of all metaphysical problems. But both adjectives are of permanent value, notwithstanding.

3. The Development of Empirical Psychology.

8. By empirical psychology is meant a study of mind which is based on observation of the facts of mental life, not derived deductively from general metaphysical concepts. It is, or aims to be, scientific rather than philosophical in that it starts with facts of observation, and aims to determine the connections between these facts and so far as possible to formulate the laws which govern these connections.

Empirical methods of studying mental life were employed as early as Plato and Aristotle, in both of whose writings valuable comments on mental phenomena, with analyses of the mind and classifications of psychical processes, are to be found. Especially is this true of Aristotle, to whom we owe the first systematic treatise on psychology. Throughout the middle ages the empirical interest was as active along with, but always strictly subordinated to, the metaphysical. In fact this is the characteristic feature of Greek, medieval, and most modern psychology before the middle of the last century — empirical methods of study cropping up from time to time, but always in subordination to rational or philosophical interests. Modern empirical psychology may properly be said to begin with John Locke (1632- 1704), with whom the empirical interest was even stronger than the metaphysical, but whose psychology is nevertheless but an outgrowth of his general metaphysical thought. It is not until the latter half — indeed, hardly until the last quarter — of the nineteenth century that psychology finally attains its independence of philosophy and its present status as a distinct science.

9. Conditions of Scientific Psychology. — A scientific psychology must not only describe mental facts, it must also explain them. Like other sciences, psychology has passed through two stages in its history — a purely descriptive stage, and a descriptive and explanatory stage. But even explanatory psychology is not necessarily scientific in the strict sense of the term, so long as psychological facts are explained, as they long were, in terms of philosophical concepts. Two important transitioned schools which appear in the prescientific period of the history of empirical psychology must therefore be discussed before we are prepared to understand the methods and ideals of modern scientific psychology- — the schools of Faculty Psychology and of Associationism.

a. Faculty Psychology

10. The so-called faculty theory of the mind in one form or another practically dominates empirical psychology from the very beginning until the eighteenth century, although the word "mental faculty" itself appears for the first time in the system of Christian Wolff (1679-1754).

According to this doctrine the mind is thought of as divided into compartments — faculties or powers — which are regarded as independent forces, and all individual mental phenomena are explained as products or expressions of these faculties. Such class-concepts of modern psychology as sensation, memory, imagination, thought, feeling, will, desire, etc., are regarded by this school not merely as convenient groups of mental processes but as actual forces which produce the phenomena included under those heads. Thus we see because we have a faculty of sensation, we think by means of our thought faculty, we act by virtue of the fact that our will is an independent faculty which is free from the restraints of physical causation.

Throughout the history of the science, however, there has ever existed a strong tendency toward the reduction of the number of faculties, the many lesser faculties being subordinated to a few ruling ones. The usual groupings have been either into two faculties — one passive and the other active, knowledge and desire or will; or into three — knowledge, feeling, and will.

Such a division of mind is analogous to the traditional grouping of teachers in the universities into the great faculties of philosophy (or arts and sciences), law, medicine, and theology; each being further divisible into a number of lesser faculties — as natural science, history, literature, etc. Just as every teacher is a member of certain of these groups, and acts by their authority; so every psychical process was thought of as a product of some particular mental faculty, and considered to be explained when referred to the proper one.

Of the two groupings, the active-passive division practically dominated the whole history of psychology until the time of Wolff, to whom reference has already been made, and who was the first to employ the term "faculty" and to formulate a systematic doctrine based on that principle. Following him, to John Nicolas Tetens (1736-1807) is due the introduction of the threefold division into intellect, feeling, and will — a third faculty, feeling, being added to the Wolffian two — which, further elaborated by Immanuel Kant, became the ruling psychological concept, on the continent at least, throughout the ensuing century.

II. Criticism of Faculty Psychology. — Modern scientific psychology, however, has rejected absolutely the entire faculty conception of the mind and of mental science, and this, I think we can say, for three reasons —

( I ) The division of the mind into faculties is an artificial.

not a natural, division — a grouping of psychical processes for convenience in study and exposition, not an actual division in the substance or reality of the mind or soul. Modern psychologists recognize that whatever the mind may in its essential nature be, it works, normally at least, as a unit, not as a collection of separate faculties; that every momentary state of consciousness is at the same time a knowing, feeling, and desiring state, the difference between the three being one of phases of a single psychosis^ rather than of three distinct and separately acting psychical forces; that whenever there is apparent division in the mind, as in the phenomena of so-called dissociation (hypnosis, hysterical somnambulism, etc.) it is a division which actually cuts through all the so-called faculties, each temporary portion of mind being not restricted to one "faculty" but manifesting itself in all the ways that a complete and normal mind would do.