The Principles of Psychology, Vols. 1-2

THE treatise which follows has in the main grown up in connection with the author's class-room instruction in Psychology, although it is true that some of the chapters are more * metaphysical,' and others fuller of detail, than is suitable for students who are going over the subject for the first time. The consequence of this is that, in spite of the exclusion of the important subjects of pleasure and pain, and moral and aesthetic feelings and judgments, the work has grown to a length which no one can regret more than the writer himself. The man must indeed be sanguine who, in this crowded age, can hope to have many readers for fourteen hundred continuous pages from his pen. But wer Vieles bringt wird Manchem etivas bringen ; and, by judi ciously skipping according to their several needs, I am sure that many sorts of readers, even those who are just begin ning the study of the subject, will find my book of use. Since the beginners are most in need of guidance, I sug gest for their behoof that they omit altogether on a first reading chapters 6, 7, 8, 10 (from page 330 to page 371), 12, 13, 15, 17, 20, 21, and 28. The better to awaken the neophyte's interest, it is possible that the wise order would be to pass directly from chapter 4 to chapters 23, 24, 25, and 26, and thence to return to the first volume again. Chapter 20, on Space-perception, is a terrible thing, which, unless written with all that detail, could not be fairly treated at all. An abridgment of it, called ' The Spatial Quale,' which appeared in the Journal of Speculative Philosophy, vol. xm. p. 64, may be found by some per sons a useful substitute for the entire chapter.

I have kept close to the point of view of natural science throughout the book. Every natural science assumes certain data uncritically, and declines to challenge the ele ments between which its own ' laws ' obtain, and from which its own deductions are carried on. Psychology, the science of finite individual minds, assumes as its data (1) thoughts and feelings, and (2) a physical world in time and space with which they coexist and which (3) they know. Of course these data themselves are discussable ; but the dis cussion of them (as of other elements) is called meta physics and falls outside the province of this book. This book, assuming that thoughts and feelings exist and are vehicles of knowledge, thereupon contends that psychology when she has ascertained the empirical correlation of the various sorts of thought or feeling with definite conditions of the brain, can go no farther — can go no farther, that is, as a natural science. If she goes farther she becomes metaphysical. All attempts to explain our phenomenally given thoughts as products of deeper-lying entities (whether the latter be named ' Soul,' ' Transcendental Ego,' ' Ideas,' or ' Elementary Units of Consciousness ') are metaphysical. This book consequently rejects both the associationist and the spiritualist theories ; and in this strictly positivistic point of view consists the only feature of it for which I feel tempted to claim originality. Of course this point of view is anything but ultimate. Men must keep thinking ; and the data assumed by psychology, just like those assumed by physics and the other natural sciences, must some time be overhauled. The effort to overhaul them clearly and thoroughly is metaphysics ; but metaphysics can only perform her task well when dis tinctly conscious of its great extent. Metaphysics fragmen tary, irresponsible, and half-awake, and unconscious that she is metaphysical, spoils two good things when she in jects herself into a natural science.

And it seems to me that the theories both of a spiritual agent and of associated * ideas' are, as they figure in the psychology-books, just such metaphysics as this. Even if their results be true, it would be as well to keep them, as thus presented, out of psychology as it is to keep the results of idealism out of physics. gers, and regarded tlie mere laws of their coexistence with brain-states as the ultimate laws for our science. The reader will in vain seek for any closed system in the book. It is mainly a mass of descriptive details, running out into queries which only a metaphysics alive to the weight of her task can hope successfully to deal with. That will perhaps be centuries hence ; and meanwhile the best mark of health that a science can show is this unfinished-seeming front.

The completion of the book has been so slow that several chapters have been published successively in Mind, the Journal of Speculative Philosophy, the Popular Science Monthly, and Scribner's Magazine. Acknowledgment is made in the proper places. The bibliography, I regret to say, is quite unsystem atic. I have habitually given my authority for special experimental facts ; but beyond that I have aimed mainly to cite books that would probably be actually used by the ordinary American college-student in his collateral reading. The bibliography in W. Volkmann von Yolkmar's Lehrbuch der Psychologic (1875) is so complete, up to its date, that there is no need of an inferior duplicate. And for more recent references, Sully's Outlines, Dewey's Psy chology, and Baldwin's Handbook of Psychology may be advantageously used.

Finally, where one owes to so many, it seems absurd to single out particular creditors ; yet I cannot resist the temptation at the end of my first literary venture to record my gratitude for the inspiration I have got from the writ ings of J. S. Mill, Lotze, Benouvier, Hodgson, and Wundt, and from the intellectual companionship (to name only five names) of Chauncey Wright and Charles Peirce in old times, and more recently of Stanley Hall, James Putnam, and Josiah Royce.

Mental Manifestations depend on Cerebral Conditions, 1. Pursuit of ends and choice are the marks of Mind's presence, 6. Reflex, semi-reflex, and voluntary acts, 12. The Frog's nervecentres, 14. General notion of the hemispheres, 20. Their Education — the Meynert scheme, 24. The phrenological con trasted with the physiological conception, 27. The localization of function in the hemispheres, 30. The motor zone, 31. Motor Aphasia, 37. The sight-centre, 41. Mental blindness, 48. The hearing-centre, 52. Sensory Aphasia, 54. Centres for smell and taste, 57. The touch-centre, 58. Man's Consciousness limited to the hemispheres, 65. The restitution of function, 67. Final correction of the Meynert scheme, 73. Conclusions, 78.

The summation of Stimuli, 82. Reaction-time, 85. Cerebral blood-supply, 97. Cerebral Thermometry, 99. Phosphorus and Thought, 101. Due to plasticity of neural matter, 105. Produces ease of action, 112. Diminishes attention, 115. Concatenated perform ances, 116. Ethical implications and pedagogic maxims, 120. Evolutionary Psychology demands a Mind-dust, 146. Some alleged proofs that it exists, 150. Refutation of these proofs, 154. Self-compounding of mental facts is inadmissible, 158. Can states of mind be unconscious? 162. Refutation of alleged proofs of unconscious thought, 164. Difficulty of stating the connection between mind and brain, 176. ' The Soul ' is logically the least objectionable hypothesis, 180. Conclusion, 182.

Time relations : lapses of Consciousness— Locke «. Descartes, 200. The 'unconsciousness' of hysterics not genuine, 202.' Minds may split into dissociated parts, 206. Space-relations! the Seat of the Soul, 214. Cognitive relations, 216. The Psychol ogist's point of view, 218. Two kinds of knowledge, acquaint ance and knowledge about, 221. Consciousness tends to the personal form, 225. It is in con stant change, 229. It is sensibly continuous, 237. • Substantive ' 'and ' transitive ' parts of Consciousness, 243. Feelings of rela tion, 245. Feelings of tendency, 249. The 'fringe' of the object, 258. The feeling of rational sequence, 261. Thought possible in any kind of mental material, 265. Thought and lan guage, 267. Consciousness is cognitive, 271. The word Object

275. Every cognition is due to one integral pulse of thought' acuity of apprehending Thought as a purely spiritual activity' 299. Emotions of Self, 305. Rivalry and conflict of one's different selves, 309. Their hierarchy, 313. What Self we love in ' Selflove,' 317. The Pure Ego, 329. The verifiable ground of the sense of personal identity, 332. The passing Thought is the only Thinker which Psychology requires, 338. Theories of Self-con sciousness : 1) The theory of the Soul, 342. 2) The Association ist theory, 350. 3) The Transcendentalist theory, 360. The muta tions of the Self, 373. Insane delusions, 375. Alternating selves, 379. Mediumships or possessions, 393. Summary, 400.

Its neglect by English psychologists, 402. Description of it, 404. To how many things can we attend at ouce? 405. Wundt's experiments on displacement of date of impressions simultaneously attended to, 410. Personal equation, 413. The varieties of attention, 416. Passive attention, 418. Voluntary attention, 420. Attention's effects on sensation, 425 ; — on discrimination, 426 ; — on recollection, 427 ;— on reaction-time, 427. The neural pro cess in attention : 1) Accommodation of sense-organ, 434. 2) Preperception, 438. Is voluntary attention a resultant or a force? 447. The effort to attend can be conceived as a resultant, 450. Conclusion, 453. Acquired Inattention, 455.

The sense of sameness, 459. Conception defined, 461. Con ceptions are unchangeable, 464. Abstract ideas, 468. Universals, 473. The conception ' of the same ' is not the ' same state ' of mind, 480. Locke on discrimination, 483. Martineau ditto, 484. Simul taneous sensations originally fuse into one object, 488. The principle of mediate comparison, 489. Not all differences are differences of composition, 490. The conditions of discrimina tion, 494. The sensation of difference, 495. The transcendentalist theory of the perception of differences uncalled for, 498. The process of analysis, 502. The process of abstraction, 505. The improvement of discrimination by practice, 508. Its two causes, 510. Practical interests limit our discrimination, 515. Reactiontime after discrimination, 523. The perception of likeness, 528. The magnitude of differences, 530. The measurement of dis-

criminative sensibility : Weber's law, 533. Fechner's interpreta tion of this as the psycho-physic law, 537. Criticism thereof, 545. The problem of the connection of our thoughts, 550. It depends on mechanical conditions, 553. Association is of objects thoughtof, not of ' ideas,' 554. The rapidity of association, 557. The ' law of contiguity,' 561. The elementary law of association, 566. Impartial redintegration, 569. Ordinary or mixed associa tion, 571. The law of interest, 572. Association by similarity, 578. Elementary expression of the difference between the three kinds of association, 581. Association in voluntary thought, 583. Similarity no elementary law, 590. History of the doctrine of association, 594.

The sensible present, 606. Its duration is the primitive timeperception, 608. Accuracy of our estimate of short durations, 611. We have no sense for empty time, 619. Variations of our time-estimate, 624. The feeling of past time is a present feeling, 627. Its cerebral process, 632. Primary memory, 643. Analysis of the phenomenon of mem ory, 648. Retention and reproduction are both caused by paths of association in the brain, 653. The conditions of goodness in memory, 659. Native retentiveness is unchangeable, 663. All im provement of memory consists in better thinking, 667. Other con ditions of good memory, 669. Recognition, or the sense of famil iarity, 673. Exact measurements of memory, 676. Forgetting, 679. Pathological cases, 681. Professor Ladd criticised, 687.

PSYCHOLOGY is the Science of Mental Life, both of its phenomena and of their conditions. The phenomena are such things as we call feelings, desires, cognitions, reason ings, decisions, and the like ; and, superficially considered, their variety and complexity is such as to leave a chaotic impression on the observer. The most natural and con sequently the earliest way of unifying the material was, first, to classify it as well as might be, and, secondly, to affiliate the diverse mental mod&d thus found, upon a simple entity, the personal Soul, of which they are taken to be so many facultative manifestations. Now, for in stance, the Soul manifests its faculty of Memory, now of Keasoning, now of Volition, or again its Imagination or its Appetite. This is the orthodox ' spiritualistic ' theory of scholasticism and of common-sense. Another and a less obvious way of unifying the chaos is to seek common ele ments in the divers mental facts rather than a common agent behind them, and to explain them constructively by the various forms of arrangement of these elements, as one explains houses by stones aad bricks. The ' associationist' schools of Herbart in Germany, and of Hume the Mills and Bain in Britain have thus constructed a psychology ivithout a soid by taking discrete 'ideas,' faint or vivid, and showing how, by their cohesions, repulsions, and forms

of succession, such tilings as reminiscences, perceptions, emotions, volitions, passions, theories, and all the other furnishings of an individual's mind may be engendered. The very Self or ego of the individual comes in this way to be viewed no longer as the pre-existing source of the representations, but rather as their last and most com plicated fruit. Now, if we strive rigorously to simplify the phenomena in either of these ways, we soon become aware of inade quacies in our method. Any particular cognition, for ex ample, or recollection, is accounted for on the soul-theory by being referred to the spiritual faculties of Cognition or of Memory. These faculties themselves are thought of as absolute properties of the soul ; that is, to take the case of memory, no reason is given why we should remember a fact as it happened, except that so to re member it constitutes the essence of our Kecollective Power. We may, as spiritualists, try to explain our mem ory's failures and blunders by secondary causes. But its successes can invoke no factors save the existence of certain objective things to be remembered on the one hand, and of our faculty of memory on the other. When, for instance, I recall my graduation-day, and drag all its incidents and emotions up from death's dateless night, no mechanical cause can explain this process, nor can any analysis reduce it to lower terms or make its nature seem other than an ultimate datum, which, whether we rebel 01 not at its mysteriousness, must simply be taken for granted if we are to psychologize at all. However the associationist may represent the present ideas as thronging and arranging themselves, still, the spiritualist insists, he has in the end to admit that something, be it brain, be it 'ideas,' be it « asso ciation/ knoics past time as past, and fills it out with this or that event. And when the spiritualist calls memory an 'irreducible faculty,' he says no more than this admission of the associationist already grants.

And yet the admission is far from being a satisfactory simplification of the concrete facts. For why should this absolute god-given Faculty retain so much better the events of yesterday than those of last year, and, best of all, those of an hour ago ? Why, again, in old age should its grasp of childhood's events seem firmest ? Why should illness and exhaustion enfeeble it ? Why should repeating an ex perience strengthen our recollection of it ? Why should drugs, fevers, asphyxia, and excitement resuscitate things long since forgotten ? If we content ourselves with merely affirming that the faculty of memory is so peculiarly con stituted by nature as to exhibit just these oddities, we seem little the better for having invoked it, for our explanation \ becomes as complicated as that of the crude facts with which we started. Moreover there is something grotesque and irrational in the supposition that the soul is equipped witl elementary powers of such an ingeniously intricate sort Why should our memory cling more easily to the near than the remote ? Why should it lose its grasp of proper sooner than of abstract names ? Such peculiarities seem quite fan tastic ; and might, for aught we can see a priori, be the precise opposites of what they are. Evidently, then, the faculty does not exist absolutely, but ivorks under conditions ; and the quest of the conditions becomes the psychologist's most interesting task.

However firmly he may hold to the soul and her re membering faculty, he must acknowledge that she never exerts the latter without a cue, and that something must al ways precede and remind us of whatever we are to recollect " An idea /" says the associationist, " an idea associated with the remembered thing ; and this explains also why things repeatedly met with are more easily recollected, for their as' sociates on the various occasions furnish so many distinct avenues of recall." But this does not explain the effects of fever, exhaustion, hypnotism, old age, and the like. And in general, the pure associationist's account of our mental life is almost as bewildering as that of the pure spiritualist. This multitude of ideas, existing absolutely, jet clinging together, and weaving an endless carpet of themselves, like dominoes in ceaseless change, or the bits of glass in a kaleidoscope, — whence do they get their fantastic laws of clinging, and why do they cling in just the shapes they dc ?

For this the associationist must introduce the order of experience in the outer world. The dance of the ideas is a copy, somewhat mutilated and altered, of the order of j phenomena. But the slightest reflection shows that phe nomena have absolutely no power to influence our ideas until they have first impressed our senses and our brain. - The bare existence of a past fact is no ground for our re membering it. Unless we have seen it, or somehow under gone it, we shall never know of its having been. The expe- Ariences of the body are thus one of the conditions of the llfaculty of memory being what it is. And a very small amount of reflection on facts shows that one part of_ the body, namely, the brain, is the part whose experiences are directly concerned. If the nervous communication be cut off between the brain and other parts, the experiences of those other parts are non-existent for the mind. The eye j is blind, the ear deaf, the hand insensible and motionless. ' And conversely, if the brain be injured, consciousness is abolished or altered, even although every other organ in the body be ready to play its normal part. A blow on the head, a sudden subtraction of blood, the pressure of an apoplectic hemorrhage, may have the first effect; whilst a very few ounces of alcohol or grains of opium or hasheesh, or a whiff of chloroform or nitrous oxide gas, are sure to have the second. The delirium of fever, the altered self of insanity, are all due to foreign matters circulating through the brain, or to pathological changes in that organ's substance. The fact that the brain is the one i immediate bodily condition of the mental operations is '• indeed so universally admitted nowadays that I need spend no more time in illustrating it, but will simply postulate it and pass on. The whole remainder of the •jbook will be more or less of a proof that the postulate was ' correct.

Bodily experiences, therefore, and more particularly brain-experiences, must take a place amongst those con ditions of the mentallife of which Psychology need take i account. The spiritualist and the associationist must both \be 'centralists,' to the extent at least of admitting that certain peculiarities in the way of working of their own favorite principles are explicable only by the fact that the brain laws are a codeterminant of the result. Our first conclusion, then, is that a certain amount of brain-physiology must be presupposed or included in Psychology.*

In still another way the pyschologist is forced to be something of a nerve-physiologist. Mental phenomena are | not only conditioned a parteante by bodily processes; but * they lead to them a parte post. That they lead to acts is of ' course the most familiar of truths, but I do not merely mean acts in the sense of voluntary and deliberate muscular performances. Mental states occasion also changes in the calibre of blood-vessels, or alteration in the heart-beats, or processes more subtle still, in glands and viscera. If these are taken into account, as well as acts which follow at some remote period because the mental state was once there, it will be safe to lay down the general law that no mental modifica tion ever occurs ivhich is not accompanied orfolloiued by a bodily change. The ideas and feelings, e.g., which these present printed characters excite in the reader's mind not only occasion movements of his eyes and nascent movements o| articulation in him, but will some day make him speak, 01 take sides in a discussion, or give advice, or choose a book to read, differently from what would have been the case had ] they never impressed his retina. Our psychology must there fore take account not only of the conditions antecedent to mental states, but of their resultant consequences as well.

But actions originally prompted by conscious intelli gence may grow so automatic by dint of habit as to be apparently unconsciously performed. Standing, walking, buttoning and unbuttoning, piano-playing, talking, even < saying one's prayers, may be done when the mind is ab- I sorbed in other things. The performances of animal instinct seern semi-automatic, and the reflex acts of selfpreservation certainly are so. Yet they resemble intelli gent acts in bringing about the same ends at which the ani mals' consciousness, on other occasions, deliberately aims.

Shall the study of such machine-like yet purposive acts as these be included in Psychology ? The boundaryline of the mental is certainly vague. It is better not to be pedantic, but to let the science be as vague as its subject, and include such phenomena as these if by so doing we can throw any light on the main business in hand. It will ere long be seen, I trust, that we can ; and that we gain much more by a broad than by a narrow conception of our subject. At a certain stage in the devel opment of every science a degree of vagueness is what best consists with fertility. On the whole, few recent for mulas have done more real service of a rough sort in psy chology than the Spencerian one that the essence of mental life and of bodily life are one, namely, ' the adjustment of inner to outer relations.' Such a formula is vagueness incarnate; but because it takes into account the fact that minds inhabit environments which act on them and on which they in turn react ; because, in short, it takes mind in the midst of all its concrete relations, it is immensely more fertile than the old-fashioned ' rational psychology,' j which treated the soul as a detached existent, sufficient * unto itself, and assumed to consider only its nature and properties. I shall therefore feel free to make any sallies into zoology or into pure nerve-physiology which may seem instructive for our purposes, but otherwise shall leave those sciences to the physiologists.

Can we state more distinctly still the manner in which the mental life seems to intervene between impressions made from without upon the body, and reactions of the body upon the outer world again ? Let us look at a few facts. If some iron filings be sprinkled on a table and a mag net brought near them, they will fly through the air for a certain distance and stick to its surface. A savage see ing the phenomenon explains it as the result of an attrac tion or love between the magnet and the filings. But let a card cover the poles of the magnet, and the filings will press forever against its surface without its ever oc curring to them to pass around its sides and thus come into

more direct contact with the object of their love. Blo~w bubbles through a tube into the bottom of a pail of water, they will rise to the surface and mingle with the air. Their action may again be poetically interpreted as due to a longing to reccmbine with the mother-atmosphere above the surface. But if you invert a jar full of water over the pail, they will rise and remain lodged beneath its bottom, shut in from the outer air, although a slight deflection from their course at the outset, or a re-descent towards the rim of the jar when they found their upward course im peded, would easily have set them free.

If now we pass from such actions as these to those of living things, we notice a striking difference. Romeo wants Juliet as the filings want the magnet ; and if no obstacles intervene he moves towards her by as straight a line as they. But Borneo and Juliet, if a wall be built between them, do not remain idiotically pressing their faces against its opposite sides like the magnet and the filings with the card. Borneo soon finds a circuitous way, by scaling the wall or otherwise, of touching Juliet's lips directly. With the filings the path is fixed; whether it reaches the end depends on accidents. With the lover it is the end which is fixed, the path may be modified indefinitely.

Suppose a living frog in the position in which we placed our bubbles of air, namely, at the bottom of a jar of water. The want jf breath will soon make him also long to rejoin the mother-atmosphere, and he will take the shortest path to his end by swimming straight upwards. But if a jar full of water be inverted over him, he will not, like the • bubbles, perpetually press his nose against its unyielding roof, but will restlessly explore the neighborhood until by re-descending again he has discovered a path round its brim to the goal of his desires. Again the fixed end, the varying means !

Such contrasts between living and inanimate perform ances end by leading men to deny that in the physical world final purposes exist at all. Loves and desires are to-day no longer imputed to particles of iron or of air. No one supposes now that the end of any activity which they may display is an ideal purpose presiding over the activity from its outset and soliciting or drawing it into being by a sort of vis afronte. The end, on the contrary, is deemed a mere passive result, pushed into being a tergo, having had, so to speak, no voice in its own production. Alter the pre-existing conditions, and with inorganic ma terials you bring forth each time a different apparent end. But with intelligent agents, altering the conditions changes the activity displayed, but not the end reached ; for here the idea of the yet unrealized end co-operates with the con ditions to determine what the activities shall be.

The pursuance of future ends and the choice of means f of their attainment arq thus the mark and criterion of the presence of mentality in a phenomenon. We all use this test to dis criminate between an intelligent and a mechanical per formance. Wo impute no mentality to sticks and stones, because they never seem to move for the sake of anything, but always when pushed, and then indifferently and with no sign of choice. So we unhesitatingly call them senseless.

Just so we form our decision upon the deepest of all philosophic problems : Is the Kosmos an expression of intelligence rational in its inward nature, or a brute ex- ] ternal fact pure and simple ? If we find ourselves, in contemplating it, unable to banish the impression that it is a realm of final purposes, that it exists for the sake of some thing, we place intelligence at the heart of it and have a religion. If, on the contrary, in surveying its irremediable flux, we can think of the present only as so much mere mechanical sprouting from the past, occurring with no reference to the future, we are atheists and materialists.

In the lengthy discussions which psychologists have carried on about the amount of intelligence displayed by lower mammals, or the amount of consciousness involved in the functions of the nerve-centres of reptiles, the same test has always been applied : Is the character of the actions such that we must believe them to be performed/or the sake of their result ? The result in question, as we shall here after abundantly see, is as a rule a useful one,— the animal is, on the whole, safer under the circumstances for bringing it forth. So far the action has a teleological character;