But whether the critics are right, or I am, on this first point, the critics are wrong about the relation of the magazine-articles to the book. With a single exception all the chapters were written for the book; and then by an after-thought some of them were sent to magazines, because the completion of the whole work seemed so distant. My lack of capacity has doubtless been great, but the charge of not having taken the utmost pains, according to my lights, in the composition of the volumes, cannot justly be laid at my door.

CONTENTS.

[CHAPTER I.]
PAGE
Introductory[1]
Psychology defined; psychology as a natural science, itsdata, [1.] The human mind and its environment, [3.] The postulatethat all consciousness has cerebral activity for its condition,[5.]
[CHAPTER II.]
Sensation in General[9]
Incoming nerve-currents, [9.] Terminal organs, [10.] 'Specificenergies,' [11.] Sensations cognize qualities, [13.] Knowledgeof acquaintance and knowledge-about, [14.] Objects ofsensation appear in space, [15.] The intensity of sensations, [16.]Weber's law, [17.] Fechner's law, [21.] Sensations are notpsychic compounds, [23.] The 'law of relativity,' [24.] Effectsof contrast, [26.]
[CHAPTER III.]
Sight[28]
The eye, [28.] Accommodation, [32.] Convergence, binocularvision, [33.] Double images, [36.] Distance, [39.] Size, color,[40.] After-images, [43.] Intensity of luminous objects, [45.]
[CHAPTER IV.]
Hearing[47]
The ear, [47.] The qualities of sound, [43.] Pitch, [44.] 'Timbre,'[45.] Analysis of compound air-waves, [56.] No fusion ofelementary sensations of sound, [57.] Harmony and discord, [58.]Discrimination by the ear, [59.]
[CHAPTER V.]
Touch, the Temperature Sense, the Muscular Sense,and Pain[60]
End-organs in the skin, [60.] Touch, sense of pressure, [60.]Localization, [61.] Sensibility to temperature, [63.] The muscularsense, [65.] Pain, [67.]
[CHAPTER VI.]
Sensations of Motion[70]
The feeling of motion over surfaces, [70.] Feelings in joints,[74.] The sense of translation, the sensibility of the semicircularcanals, [75.]
[CHAPTER VII.]
The Structure of the Brain[78]
Embryological sketch, [78.] Practical dissection of the sheep'sbrain, [81.]
[CHAPTER VIII.]
The Functions of the Brain[91]
General idea of nervous function, [91.] The frog's nerve-centres,[92.] The pigeon's nerve-centres, [96.] What the hemispheresdo, [97.] The automaton-theory, [101.] The localizationof functions, [104.] Brain and mind have analogous 'elements,'sensory and motor, [105.] The motor zone, [106.] Aphasia, [108.]The visual region, [110.] Mental blindness, [112.] The auditoryregion, mental deafness, [113.] Other centres, [116.]
[CHAPTER IX.]
Some General Conditions of Neural Activity[120]
The nervous discharge, [120.] Reaction-time, [121.] Simplereactions, [122.] Complicated reactions, [124.] The summationof stimuli, [128.] Cerebral blood-supply, [130.] Brain-thermometry,[131.] Phosphorus and thought, [132.]
[CHAPTER X.]
Habit[134]
Its importance, and its physical basis, [134.] Due to pathwaysformed in the centres, [136.] Its practical uses, [138.] Concatenatedacts, [140.] Necessity for guiding sensations in secondarilyautomatic performances, [141.] Pedagogical maxims concerningthe formation of habits, [142.]
[CHAPTER XI.]
The Stream of Consciousness[151]
Analytic order of our study, [151.] Every state of mind formspart of a personal consciousness, [152.] The same state of mindis never had twice, [154.] Permanently recurring ideas are afiction, [156.] Every personal consciousness is continuous, [157.]Substantive and transitive states, [160.] Every object appearswith a 'fringe' of relations, [163.] The 'topic' of the thought,[167.] Thought may be rational in any sort of imagery, [168.]Consciousness is always especially interested in some one partof its object, [170.]
[CHAPTER XII.]
The Self[176]
The Me and the I, [176.] The material Me, [177.] The socialMe, [179.] The spiritual Me, [181.] Self-appreciation, [182.] Self-seeking,bodily, social, and spiritual, [184.] Rivalry of the Mes,[186.] Their hierarchy, [190.] Teleology of self-interest, [193.]The I, or 'pure ego,' [195.] Thoughts are not compounded of'fused' sensations, [196.] The 'soul' as a combining medium,[200.] The sense of personal identity, [201.] Explained by identityof function in successive passing thoughts, [203.] Mutationsof the self, [205.] Insane delusions, [207.] Alternating personalities,[210.] Mediumships or possessions, [212.] Who is theThinker, [215.]
[CHAPTER XIII.]
Attention[217]
The narrowness of the field of consciousness, [217.] Dispersedattention, [218.] To how much can we attend at once?[219.] The varieties of attention, [220.] Voluntary attention, itsmomentary character, [224.] To keep our attention, an objectmust change, [226.] Genius and attention, [227.] Attention'sphysiological conditions, [228.] The sense-organ must beadapted, [229.] The idea of the object must be aroused, [232.]Pedagogic remarks, [236.] Attention and free-will, [237.]
[CHAPTER XIV.]
Conception[239]
Different states of mind can mean the same, [239.] Conceptionsof abstract, of universal, and of problematic objects, [240.]The thought of 'the same' is not the same thought overagain, [243.]
[CHAPTER XV.]
Discrimination[244]
Discrimination and association; definition of discrimination,[244.] Conditions which favor it, [245.] The sensation of difference,[246.] Differences inferred, [248.] The analysis of compoundobjects, [248.] To be easily singled out, a quality shouldalready be separately known, [250.] Dissociation by varyingconcomitants, [251.] Practice improves discrimination, [252.]
[CHAPTER XVI.]
Association[253]
The order of our ideas, [253.] It is determined by cerebrallaws, [255.] The ultimate cause of association is habit, [256.]The elementary law in association, [257.] Indeterminateness ofits results, [258.] Total recall, [259.] Partial recall, and the lawof interest, [261.] Frequency, recency, vividness, and emotionalcongruity tend to determine the object recalled, [264.] Focalizedrecall, or 'association by similarity,' [267.] Voluntary trains ofthought, [271.] The solution of problems, [273.] Similarity noelementary law; summary and conclusion, [277.]
[CHAPTER XVII.]
The Sense of Time[280]
The sensible present has duration, [280.] We have no sensefor absolutely empty time, [281.] We measure duration by theevents which succeed in it, [283.] The feeling of past time is apresent feeling, [285.] Due to a constant cerebral condition, [286.]
[CHAPTER XVIII.]
Memory[287]
What it is, [287.] It involves both retention and recall, [289.]Both elements explained by paths formed by habit in the brain,[290.] Two conditions of a good memory, persistence and numerousnessof paths, [292.] Cramming, [295.] One's native retentivenessis unchangeable, [296.] Improvement of the memory,[298.] Recognition, [299.] Forgetting, [300.] Pathologicalconditions, [301.]
[CHAPTER XIX.]
Imagination[302]
What it is, [302.] Imaginations differ from man to man; Galton'sstatistics of visual imagery, [303.] Images of sounds, [306.]Images of movement, [307.] Images of touch, [308.] Loss ofimages in aphasia, [309.] The neural process in imagination,[310.]
[CHAPTER XX.]
Perception[312]
Perception and sensation compared, [312.] The perceptivestate of mind is not a compound, [313.] Perception is of definitethings, [316.] Illusions, [317.] First type: inference of the moreusual object, [318.] Second type: inference of the object ofwhich our mind is full, [321.] 'Apperception,' [326.] Geniusand old-fogyism, [327.] The physiological process in perception,[329.] Hallucinations, [330.]
[CHAPTER XXI.]
The Perception of Space[335]
The attribute of extensity belongs to all objects of sensation,[335.] The construction of real space, [337.] The processeswhich it involves: 1) Subdivision, 338; 2) Coalescence of differentsensible data into one 'thing,' 339; 3) Location in an environment,340; 4) Place in a series of positions, 341; 5) Measurement,[342.] Objects which are signs, and objects whichare realities, [345.] The 'third dimension,' Berkeley's theory ofdistance, [346.] The part played by the intellect in space-perception,[349.]
[CHAPTER XXII.]
Reasoning[351]
What it is, [351.] It involves the use of abstract characters,[353.] What is meant by an 'essential' character, [354.] The'essence' varies with the subjective interest, [358.] The twogreat points in reasoning, 'sagacity' and 'wisdom,' [360.] Sagacity,[362.] The help given by association by similarity, [364.]The reasoning powers of brutes, [367.]
[CHAPTER XXIII.]
Consciousness and Movement[370]
All consciousness is motor, [370.] Three classes of movementto which it leads, [372.]
[CHAPTER XXIV.]
Emotion[373]
Emotions compared with instincts, [373.] The varieties ofemotion are innumerable, [374.] The cause of their varieties,[375.] The feeling, in the coarser emotions, results from thebodily expression, [375.] This view must not be called materialistic,[380.] This view explains the great variability of emotion,[381.] A corollary verified, [382.] An objection replied to, [383.]The subtler emotions, [384.] Description of fear, [385.] Genesisof the emotional reactions, [386.]
[CHAPTER XXV.]
Instinct[391]
Its definition, [391.] Every instinct is an impulse, [392.] Instinctsare not always blind or invariable, [395.] Two principlesof non-uniformity, [398.] Enumeration of instincts in man, [406.]Description of fear, [407.]
[CHAPTER XXVI.]
Will[415]
Voluntary acts, [415.] They are secondary performances, [415.]No third kind of idea is called for, [418.] The motor-cue, [420.]Ideo-motor action, [432.] Action after deliberation, [428.] Fivechief types of decision, [429.] The feeling of effort, [434.]Healthiness of will, [435.] Unhealthiness of will, [436.] Theexplosive will: (1) from defective inhibition, 437; (2) fromexaggerated impulsion, [439.] The obstructed will, [441.] Effortfeels like an original force, [442.] Pleasure and pain assprings of action, [444.] What holds attention determines action,[448.] Will is a relation between the mind and its'ideas,' [449.] Volitional effort is effort of attention, [450.] Thequestion of free-will, [455.] Ethical importance of the phenomenonof effort, [458.]
[EPILOGUE.]
Psychology and Philosophy[461]
What the word metaphysics means, [461.] Relation of consciousnessto the brain, [462.] The relation of states of mind totheir 'objects,' [464.] The changing character of consciousness,[466.] States of consciousness themselves are not verifiablefacts, [467.]

PSYCHOLOGY.

CHAPTER I.
INTRODUCTORY.

The definition of Psychology may be best given in the words of Professor Ladd, as the description and explanation of states of consciousness as such. By states of consciousness are meant such things as sensations, desires, emotions, cognitions, reasonings, decisions, volitions, and the like. Their 'explanation' must of course include the study of their causes, conditions, and immediate consequences, so far as these can be ascertained.

Psychology is to be treated as a natural science in this book. This requires a word of commentary. Most thinkers have a faith that at bottom there is but one Science of all things, and that until all is known, no one thing can be completely known. Such a science, if realized, would be Philosophy. Meanwhile it is far from being realized; and instead of it, we have a lot of beginnings of knowledge made in different places, and kept separate from each other merely for practical convenience' sake, until with later growth they may run into one body of Truth. These provisional beginnings of learning we call 'the Sciences' in the plural. In order not to be unwieldy, every such science has to stick to its own arbitrarily-selected problems, and to ignore all others. Every science thus accepts certain data unquestioningly, leaving it to the other parts of Philosophy to scrutinize their significance and truth. All the natural sciences, for example, in spite of the fact that farther reflection leads to Idealism, assume that a world of matter exists altogether independently of the perceiving mind. Mechanical Science assumes this matter to have 'mass' and to exert 'force,' defining these terms merely phenomenally, and not troubling itself about certain unintelligibilities which they present on nearer reflection. Motion similarly is assumed by mechanical science to exist independently of the mind, in spite of the difficulties involved in the assumption. So Physics assumes atoms, action at a distance, etc., uncritically; Chemistry uncritically adopts all the data of Physics; and Physiology adopts those of Chemistry. Psychology as a natural science deals with things in the same partial and provisional way. In addition to the 'material world' with all its determinations, which the other sciences of nature assume, she assumes additional data peculiarly her own, and leaves it to more developed parts of Philosophy to test their ulterior significance and truth. These data are—