CONTENTS

PAGE

PREFACE ....... V

PART I. THE LOGICAL AND METAPHYSICAL STATUS
OF FACTORS IN PSYCHOLOGY

CHAPTER

I. WHY DOES THE PSYCHOLOGIST NEED FACTORS ? . 3

II. FACTORS ARE VARIOUSLY USED FOR DESCRIP-
TION, PREDICTION, CAUSAL EXPLANATION . 14

III. THE GENERAL NATURE OF THE FACTORIAL TECH-
NIQUE ....... 72

IV. THE LOGICAL STATUS OF MENTAL FACTORS. . 95

V. THE DERIVATION OF THE CHIEF FACTOR THEORIES 139

VI. THE DIFFERENCES BETWEEN P-, Q-, AND R-

TECHNIQUES . . . . . 169

VII. THE METAPHYSICAL STATUS OF MENTAL FACTORS 2IO
VIII. SUMMARY AND CONCLUSIONS . . . 249

PART II. THE RELATIONS BETWEEN DIFFERENT
METHODS OF FACTOR-ANALYSIS

IX. CLASSIFICATION OF METHODS . . . 255

X. VARIANCE, COVARIANCE, AND CORRELATION . 2/1

XI. CORRELATIONS BETWEEN TESTS AND BETWEEN

PERSONS ...... 289

xiii