The Principles of Psychology, Volume 2 (of 2)
PROFESSOR OF PSYCHOLOGY IN HARVARD UNIVERSITY
IN TWO VOLUMES
HENRY HOLT AND COMPANY
Its distinction from perception, 1. Its cognitive function—acquaintancewith qualities, 3. No pure sensations after the firstdays of life, 7. The 'relativity of knowledge,' 9. The law ofcontrast, 13. The psychological and the physiological theoriesof it, 17. Hering's experiments, 20. The 'eccentric projection'of sensations, 31.
Our images are usually vague, 45. Vague images not necessarilygeneral notions, 48. Individuals differ in imagination;Gabon's researches, 50. The 'visile' type, 58. The 'audile'type, 60. The 'motile' type, 61. Tactile images, 65. The neuralprocess of imagination, 68. Its relations to that of sensation, 72.
The Perception of 'Things,' 76
Perception and sensation, 76. Perception is of definite andprobable things, 82. Illusions, 85;—of the first type, 86;—ofthe second type, 95. The neural process in perception, 103.'Apperception,' 107. Is perception an unconscious inference?111. Hallucinations, 114. The neural process in hallucination,122. Binet's theory, 129. 'Perception-time,' 131.
The Perception of Space, 134
The feeling of crude extensity, 134. The perception of spatialorder, 145. Space-'relations,' 148. The meaning of localization,158. 'Local signs,' 155. The construction of 'real' space, 166.The subdivision of the original sense-spaces, 167. The sensation[Pg iv]of motion over surfaces, 171. The measurement of the sense-spacesby each other, 177. Their summation, 181. Feelings ofmovement in joints, 189. Feelings of muscular contraction, 197.Summary so far, 202. How the blind perceive space, 203.Visual space, 211. Helmholtz and Reid on the test of a sensation,216. The theory of identical points, 222. The theory of projection,228. Ambiguity of retinal impressions, 231;—of eye-movements,234. The choice of the visual reality, 237. Sensations whichwe ignore, 240. Sensations which seem suppressed, 243. Discussionof Wundt's and Helmholtz's reasons for denying thatretinal sensations are of extension, 248. Summary, 268. Historicalremarks, 270.
The Perception of Reality, 283
Belief and its opposites, 283. The various orders of reality,287. 'Practical' realities, 293. The sense of our own bodilyexistence is the nucleus of all reality, 297. The paramount realityof sensations, 299. The influence of emotion and active impulseon belief, 307. Belief in theories, 311. Doubt, 318. Relationsof belief and will, 320.
'Recepts,' 327. In reasoning, we pick out essential qualities,329. What is meant by a mode of conceiving, 332. What isinvolved in the existence of general propositions, 337. The twofactors of reasoning, 340. Sagacity, 343. The part played byassociation by similarity, 345. The intellectual contrast betweenbrute and man: association by similarity the fundamental humandistinction, 348. Different orders of human genius, 360.
The Production of Movement, 373
Its definition, 383. Instincts not always blind or invariable,389. Two principles of non-uniformity in instincts: 1) Theirinhibition by habits, 394; 2) Their transitoriness, 398. Man has[Pg v]more instincts than any other mammal, 403. Reflex impulses,404. Imitation, 408. Emulation, 409. Pugnacity, 409. Sympathy,410. The hunting instinct, 411. Fear, 415. Acquisitiveness,422. Constructiveness, 426. Play, 427. Curiosity, 429.Sociability and shyness, 430. Secretiveness, 432. Cleanliness,434. Shame, 435. Love, 437. Maternal love, 439.
The Emotions, 442
Instinctive reaction and emotional expression shade imperceptiblyinto each other, 442. The expression of grief, 443; offear, 446; of hatred, 449. Emotion is a consequence, not thecause, of the bodily expression, 449. Difficulty of testing thisview, 454. Objections to it discussed, 456. The subtler emotions,468. No special brain-centres for emotion, 472. Emotional differencesbetween individuals, 474. The genesis of the variousemotions, 477.
Voluntary movements: they presuppose a memory of involuntarymovements, 487. Kinæsthetic impressions, 488. No needto assume feelings of innervation, 503. The 'mental cue' for amovement may be an image of its visual or auditory effects aswell as an image of the way it feels, 518. Ideo-motor action, 522.Action after deliberation, 528. Five types of decision, 531. Thefeeling of effort, 535. Unhealthiness of will: 1) The explosivetype, 537; 2) The obstructed type, 546. Pleasure andpain are not the only springs of action, 549. All consciousness isimpulsive, 551. What we will depends on what idea dominatesin our mind, 559. The idea's outward effects follow from thecerebral machinery, 560. Effort of attention to a naturallyrepugnant idea is the essential feature of willing, 562. Thefree-will controversy, 571. Psychology, as a science, can safelypostulate determinism, even if free-will be true, 576. The educationof the Will, 579. Hypothetical brain-schemes, 582.
Necessary Truths and the Effects of Experience, 617
Programme of the chapter, 617. Elementary feelings areinnate, 618. The question refers to their combinations, 619.What is meant by 'experience,' 620. Spencer on ancestral experience,620. Two ways in which new cerebral structure arises:the 'back-door' and the 'front-door' way, 625. The genesis ofthe elementary mental categories, 631. The genesis of thenatural sciences, 633. Scientific conceptions arise as accidentalvariations, 636. The genesis of the pure sciences, 641. Series ofevenly increasing terms, 644. The principle of mediate comparison,645. That of skipped intermediaries, 646. Classification,646. Predication, 647. Formal logic, 648. Mathematicalpropositions, 652. Arithmetic, 653. Geometry, 656. Our doctrineis the same as Locke's, 661. Relations of ideas v. couplingsof things, 663. The natural sciences are inward ideal schemeswith which the order of nature proves congruent, 666. Metaphysicalprinciples are properly only postulates, 669. Æstheticand moral principles are quite incongruent with the order ofnature, 672. Summary of what precedes, 675. The origin ofinstincts, 678. Insufficiency of proof for the transmission to thenext generation of acquired habits, 681. Weismann's views, 683.Conclusion, 688.
After inner perception, outer perception! The nextthree chapters will treat of the processes by which we cognizeat all times the present world of space and the materialthings which it contains. And first, of the processcalled Sensation.
SENSATION AND PERCEPTION DISTINGUISHED.
The words Sensation and Perception do not carry verydefinitely discriminated meanings in popular speech, and inPsychology also their meanings run into each other. Bothof them name processes in which we cognize an objectiveworld; both (under normal conditions) need the stimulationof incoming nerves ere they can occur; Perceptionalways involves Sensation as a portion of itself; and Sensationin turn never takes place in adult life without Perceptionalso being there. They are therefore names for differentcognitive functions, not for different sorts of mentalfact. The nearer the object cognized comes to being asimple quality like 'hot,' 'cold,' 'red,' 'noise,' 'pain,' apprehendedirrelatively to other things, the more the stateof mind approaches pure sensation. The fuller of relationsthe object is, on the contrary; the more it is somethingclassed, located, measured, compared, assigned to a function,etc., etc.; the more unreservedly do we call the stateof mind a perception, and the relatively smaller is the partin it which sensation plays.
Sensation, then, so long as we take the analytic point of[Pg 2]view, differs from Perception only in the extreme simplicity of itsobject or content. Its function is that of mere acquaintancewith a fact. Perception's function, on the other hand, isknowledge about a fact; and this knowledge admits ofnumberless degrees of complication. But in both sensationand perception we perceive the fact as an immediatelypresent outward reality, and this makes them differ from'thought' and 'conception,' whose objects do not appearpresent in this immediate physical way. From the physiological[Pg 3]point of view both sensations and perceptions differ from'thoughts' (in the narrower sense of the word) in the fact thatnerve-currents coming in from the periphery are involved in theirproduction. In perception these nerve-currents arouse voluminousassociative or reproductive processes in the cortex; but whensensation occurs alone, or with a minimum of perception, the accompanyingreproductive processes are at a minimum too.
I shall in this chapter discuss some general questionsmore especially relative to Sensation. In a later chapterperception will take its turn. I shall entirely pass by theclassification and natural history of our special 'sensations,'such matters finding their proper place, and beingsufficiently well treated, in all the physiological books.
THE COGNITIVE FUNCTION OF SENSATION.
A pure sensation is an abstraction; and when we adultstalk of our 'sensations' we mean one of two things: eithercertain objects, namely simple qualities or attributes likehard, hot, pain; or else those of our thoughts in whichacquaintance with these objects is least combined withknowledge about the relations of them to other things. Aswe can only think or talk about the relations of objectswith which we have acquaintance already, we are forced topostulate a function in our thought whereby we first becomeaware of the bare immediate natures by which our severalobjects are distinguished. This function is sensation.And just as logicians always point out the distinctionbetween substantive terms of discourse and relations foundto obtain between them, so psychologists, as a rule, areready to admit this function, of the vision of the terms ormatters meant, as something distinct from the knowledgeabout them and of their relations inter se. Thought withthe former function is sensational, with the latter, intellectual.Our earliest thoughts are almost exclusively sensational.They merely give us a set of thats, or its, of subjects[Pg 4]of discourse, with their relations not brought out. The firsttime we see light, in Condillac's phrase we are it ratherrather than see it. But all our later optical knowledge isabout what this experience gives. And though we werestruck blind from that first moment, our scholarship in thesubject would lack no essential feature so long as our memoryremained. In training-institutions for the blind theyteach the pupils as much about light as in ordinary schools.Reflection, refraction, the spectrum, the ether-theory, etc.,are all studied. But the best taught born-blind pupil ofsuch an establishment yet lacks a knowledge which theleast instructed seeing baby has. They can never show himwhat light is in its 'first intention'; and the loss of thatsensible knowledge no book-learning can replace. All thisis so obvious that we usually find sensation 'postulated'as an element of experience, even by those philosophers whoare least inclined to make much of its importance, or topay respect to the knowledge which it brings.
But the trouble is that most, if not all, of those whoadmit it, admit it as a fractional part of the thought, in theold-fashioned atomistic sense which we have so often criticised.
Take the pain called toothache for example. Againand again we feel it and greet it as the same real item inthe universe. We must therefore, it is supposed, have adistinct pocket for it in our mind into which it and nothingelse will fit. This pocket, when filled, is the sensation oftoothache; and must be either filled or half-filled wheneverand under whatever form toothache is present to ourthought, and whether much or