Chapter XII: Results (2)

Coenæsthesis, 41, 99, 145, 286, 288.

Cognition, immediate or intuitive, 5, 14-16, 294;
presentative and representative, 9, 13, 217, 330;
nature of, in dreams, 168, 172;
nature of, generally, 295, 331;
philosophic problems of, 346.

Colour, external reality of, 8, 37;
illusory perception of, 37, 88;
subjective complementary colours (colour-contrast), 67, 83.

Coloured media, objects seen through, 82.

Common cognition, and truth, 337;
genesis and validity of, 353.

Common experience distinguished from
individual, 26, 27, 137, 209, 214, 336, 351;
illusion as, 47,325, 337.

Common sense, intuitions of, 346, 349, 352, 357.

Complementary colours, 67, 83.

Concave, apparent conversion of, into convex, 84.

Conjuror, tricks of, 56, 106.

Consciousness, veracity of, 192, 205;
inspection of phenomena of, 196;
of self, 283, 285.

Consensus, the standard of truth, 7, 8, 211, 325, 338, 357.

Conservation of energy, 343.

Construction, rational, in dreams, 170.

Continuum, the perception of the world as, 52, 56, note[24].

Correction of illusion, in sense-illusion, 38, 124, 137;
dreams, 182;
introspection, 210;
insight, 229;
memory, 291;
historical correction 338;
intellectual processes involved in, 351.

Criterion of illusion, 337.

Cudworth, R., 161

D.

Deception of the senses, 19;
self-deception, 200;
conscious deception of others, 222.

Delboeuf, J., 175, note[97], 235, note[113].

_Delirium tremens_, 118, note[62].

Democritus, 130.

De Quincey, 253, 280.

Descartes, R., 116, 350.

Dickens, Charles, 277.

Direction, illusory sense of, in vision, 66, 71, 73;
in hearing, 72, 75.

Disease. _See_ Abnormal life.

Dissolution. _See_ Evolution.

Doubt, starting-point in philosophy, 350.

Dreams, relation of, to illusions of sense, 18, 130;
and waking experience, 127;
theories of, 128;
physiology of, 131;
extent of, in sleep, 132;
psychological conditions of, 136;
excitants of, 139, 143;
exaggeration in, 147;
symbolism of, 149;
as results of automatic activity of centres, 151;
as results of association, 153;
structure of, 156;
incoherent, 156;
coherent, 161;
action of feeling in, 164;
play of associative dispositions in, 168;
co-operation of attention and intelligence in, 172;
limits of intelligence in, 180;
after-dreams, 183, 274;
relation of, to hypnotic condition, 185;
experience of, in relation to errors of memory, 273.

E.

Eccentricity, law of, 59.

Ego. _See_ Self.

Emotion, and illusion of perception, 103;
and hallucination, 115;
and bodily sensations, 150;
control of dreams by, 164;
introspection of, 199;
and illusion of introspection, 203;
and æsthetic intuition, 213;
and illusion of memory, 270;
and illusion of belief, 306, 324;
and cognition generally, 357, note[159].

Empiricism, philosophic, 348.

_Ennui_, and sense of time, 250.

Environment, sources of sense-illusion in, 47, 48, 70;
view of, in mental disease, 290, 326;
view of, in normal life, 323;
action of, in assimilating belief, 339.

Error, immediate and mediate, 6, 334.

Esquirol, J.E.D., 12, note[2].

Evolution, relation of, to dissolution, 122;
of power of introspection, 209;
of power of insight, 230;
and self-assertion, 320;
evolutionist's view of error, 339;
doctrine of, as science, 346.

Exaggeration, in interpretation of sensations, 65;
in dream-interpretation, 147;
in memory, 269.

Expectation, preliminary to perception, 30;
and illusory perception, 93, 102, 106;
nature of, 295;
and memory, 298;
of new experience, 301;
of remote events, 302;
measurement of duration in, 302;
action of imagination in, 305;
extension of meaning of, 307, 308.

Experience, effect of, in perception, 22, 68, 85, 86, 91;
external and internal, 194, 210;
revivals of waking, in dreams, 152;
effects of present, on retrospection, 267;
anticipation of new, 301.

External world. _See_ World.

F.

Fallacy and illusion 6, 335;
of testimony, 265.

Familiarity, sense of, in new objects, 272, 281.

Fechner, G.T., 51.

Ferrier, Dr., 32, note[12], 58, note[26].

Fiction, as producing illusion, 278, 279, 311.

Fitness. _See_ Adaptation.

Flattery, _rationale_ of, 200, 222.

Forgetfulness and illusion, 278, 279, 311.

Free-will, doctrine of, 207, 342, 356.

Future. _See_ Expectation.

G.

Galton, F., 117.

Ghosts. _See_ Hallucination.

Goethe, 116, 117, 280 and note[131].

Griesinger, W., 13, note[2], 63, note[31], 66, note[32], 115, 118,
note[62], 119, note[64], 120, note[66], 290, note[135], 327,
note[146].

Gruithuisen, 143, 144.

Gurney, E., 224, note[109].

H.

Hall, G.S., 186, note[102].

Hallucination, and illusion, 11, 109, 111, 112, 121;
and subjective sensation, 63, 109, 121;
sensory and motor, 66;
nervous conditions of, 112-114;
incomplete and complete, 113;
as having either central or peripheral origin, 113;
causes of, classified, 115;
in sane condition, 116;
in insanity, 118;
visual and auditory, 119;
dreams regarded as, 139, 151;
hypnagogic, 143;
after-dreams and ghosts, 183;
of memory, 271;
relation of, to errors of belief, 322;
intuition of external world regarded as, 355.

Happiness, feeling of, 200.

Harmful, illusion as, 188, 229, 292, 339.

Harmless, illusions as, 124, 292, 341.

Hartley, D., 139, 256, note[124], 279.

Hearing, as mode of perception, 34, 48;
localization of impression in, 60;
sense of direction in, 72;
activity of, in sleep, 140;
and muscular sense, 171.

Heidenhain, Dr., 186-188.

Helmholtz, H., 22, 23, note[7], 44, 51, 54 and note[22], 55, note[23],
57, 67, note[33], 78, note[39], 80, 85, note[43], 88, 90, 207,
note[105].

Heraclitus, 137.

Heredity, and illusion of memory, 280;
action of, in perpetuating intuition, 359.

Hering, E., 67, note[33].

Hodgson, Shadworth H., 347, note[153].

Holland, Sir H., 277.

Hood, Thomas, 146.

Hope, illusory. _See_ Expectation.

Hoppe, Dr. J.I., 51, 58, note[26].

Horwicz, A., 145, note[85].

Hume, D., 355.

Huxley, Professor T., 119, note[1].

Hyperæsthesia, 65.

Hypnotism, 185.

Hypochondria, 65.

Hypothesis, as illusory, 310, 311.

I.

Idealism, 348.

Identity, cases of mistaken, 267.

Identity, personal, confusion of, in dreams, 163;
consciousness of, 241, 267, 282, 285;
illusory forms of, 283;
gross disturbances of, in normal life, 287;
in abnormal life, 289;
momentary confusions of, 293.

Illusion, definition of, 1;
varieties of, 9;
extent of, 328;
_rationale_ of, 331, 337.

Image (physical). _See_ Reflection.

Image (mental), in perception, 22;
seat of, 32;
in dreams, 138;
mnemonic, 236.

Imagination, play of, in perception, 95, 99;
and sense-illusion, 106;
nature of, in dreaming, 136, 161;
as antecedent of dream, 152, 158;
as poetic interpretation of nature, 224;
memory corrupted by effect of past, 264, 273, 277;
present, creating the semblance of recollection, 267, 271;
play of, in expectation, 305;
as element of illusion generally, 333.

Immediate. _See_ Cognition.

Individual, and common experience, 26, 27, 137, 209, 214, 336;
dream-experience as, 44, 68;
internal experience as, 209;
memory as, 232;
belief and truth, 338.

Inference, and immediate knowledge, 6, 334;
in perception, 22, 26, 68;
in belief, 295.

Innate, recollection as, 280;
principles, 295, 356.

Insane, sense-illusions of, 63, 65, 111;
hallucinations of, 118;
dreaming and state of, 182;
mnemonic illusions of, 278, 289;
beliefs of, 327.

Insight, nature of, 217;
illusions of, defined, 220;
passive illusions of, 220;
histrionic illusion, 222;
active illusions of, 223;
poetic interpretation of nature, 224;
value of faculty of, 228.

Interpretation, in correct perception, 22;
of impression and experience, 70;
and volition, 95;
and fixed habits of mind, 101;
and temporary attitude of mind, 102;
of sensations in dreams, 137, 147;
of internal feelings, 203;
of others' feelings, 217;
of nature by poet, 225;
recollection as, 242.

Introspection, nature of, 14, 189;
illusory forms of, 190;
confusion of inner and outer experiences, 194;
inaccurate inspection of feelings, 196;
presentation and representation confused, 199;
feelings and inferences from these, 203;
moral self-scrutiny, 204;
philosophic, 205;
value of, 208.

Intuition. _See_ Cognition.

Intuitivism, 348.

J.

Jackson, Dr. J. Hughlings, 27, note[9], 33, 123, note[67].

Johnson, Dr., 116.

K.

_Klang_, as compound sensation, 53.

Knowledge. _See_ Cognition.

L.

Language, function of, 195.

Leibnitz, 133.

Lélut, L.F., 120, note[66].

Lessing, G. E., 133, note[73].

Leuret, 290, note[135].

Lewes, G.H., 28, 32, note[12], 52, note[30], 62, note[1], 68,
note[35], 89, note[45], 115, note[58], 150.

Life, our estimate of, 323, 326, 327.

Light, sensation and perception of, 59;
effects of reflection and refraction, of, 73;
representation, of, in painting, 88, 91;
action of, in sleep, 140.

Localization, as local discrimination of sensations, 52;
as localizing of sensations, 59, 60;
illusory, 61, 82;
in hallucination, 118, 119;
in dreaming, 148;
of events in time, in memory, 238, 245;
in expectation, 304.

Locke, 133, note[73].

Lotze, H., 60, note[29].

Lover, illusion of, 224, 227, 342.

Luminosity of painting, 88, 91.

Lustre, as compound sensation, 54.

Lyell, Sir Charles, 311.

M.

Magic, arts of, 73.

Magnitude, apparent, in vision, 75, note[37];
perception of, in pictorial art, 88, 91;
of time-intervals, 245, 249;
recollection of, 268.

Malebranche, 116.

Mankind, our views of, 322.

Matter. _See_ World (material).

Maudsley, Dr. H., 32, note[12].

Maury, A., 140, 143, 153, note[92], 159, 163, note[94], 173.

Mayer, Dr. A., 66, note[32].

Measurement, subjective, of time, 245.

Media, coloured, illusions connected with presence of, 82.

Memory, nature of, 9, 13, 231;
veracity of, 232, 290;
defined, 234;
psychology of, 236;
physiology of, 237;
localization of events in, 238;
and sense of personal identity, 241, 283;
illusions of, 241;
illusory localization, 245, 256;
distortions of, 261;
hallucinations of, 271;
illusions respecting personal identity, 283;
relation of, to belief, 295;
compared with expectation, 297;
and inference, 335.

Metempsychosis, 294.

Meyer, H., 83, 144.

Mill, J.S., 298, note[138], 309.

Mirrors, as means of delusion, 73.

Misanthropist, 2, 323.

Mitchell, Dr. Weir, 62.

Monomania, 111.

Moral, intuition, 216;
self-inspection, 204.

Motor illusions. _See_ Muscular sense.

Movement, apparent, 50, 57, 73, 81, 95, 107;
in dreams, 142, 154.

Müller, Johannes, 58, note[27], 100, 117, 143.

_Muscæ volitantes_, 118, note[62].

Muscular sense, in perception, 23;
illusions connected with, 50, 57, 62, 66;
co-operation, of, in dreams, 142, 154.

Music, subjective interpretation of, 223.

N.

Natural selection, effect of, in eliminating error, 340.

Nature, personification of, 224;
uniformity of, 344, 360.

Necessity, idea of, 349, 360.

Nervous system, and conditions of perception, 31;
connections of, 32, 169;
function of, and force of stimulus, 47, 50;
prolonged activity of, 55;
specific energy of, 58;
variations in state of, 64;
fatigue of, 65, 115;
disease of, _ibid._;
nervous conditions of hallucination, 112, 115;
nervous dissolution and evolution, 122;
condition of, in sleep, 131;
in hypnotic condition, 186;
nervous conditions of memory, 237;
nervous conditions of illusion in general, 334.

Normal life, relation of,
to abnormal, 1, 121, 124, 182, 277, 284, note[132];
hallucinations of, 116.

O.

Object, nature of, 36, 353.

Objective and subjective experience, 26, 27, 137, 214.

Old age, dreams how regarded in, 276.

Oneirocritics, 129.

Opera, illusion connected with, 104.

Optimism, 323, 327, 342.

Organic sensations, discrimination of, 41;
interpretation of, 99;
in sleep, 145, 148.

Organism, conditions of illusion in, 47, 50;
relation of our conception of the universe to sensibilities of, 343.

Orientation, 125, 138.

P.

Pain, recollection of, 264, 270.

Painting, representation of third dimension by, 77;
apparent movement of eye in portrait, 81;
discrepancies between, and object in magnitude and luminosity, 88;
realization of, and mental preparation, 105;
realization of, by animals, 105.

Paræsthesia, 68.

Paralysis of ocular muscles, 66.

Passive, and active factor in perception, 27;
and active illusion, 45.

Percept, 22;
and sense-impression, 59.

Perception, a form of immediate knowledge, 10, 13, 17, 18;
external and internal, 14;
philosophy of, 14, 20, 22, 36, 346, 348, 353, 355, 359;
illusions of, 19, 35;
psychology of, 20;
and inference, 22, 26, 76;
physiological conditions of, 31.

Persistent objects, representation of, 312.

Persistent self. _See_ Personal identity.

Personal equation, in perception, 101;
in æsthetic intuition, 214;
in memory, 292;
in belief, 324.

Personal identity, consciousness of, 241, 282, 285;
illusions connected with, 283;
disturbances in sense of, 287;
sense of, in insanity, 289;
momentary confusions of, 293;
philosophic problem of, 285, 354, 360.

Personification of nature, 224.

Perspective, linear, 79, 97, 98;
aerial, 80;
of memory, 245.

Pessimism, 323, 327.

Phenomenalism, 348.

Philosophy, conception of illusion by, 7, 36, 205, 285, 349;
of mind, 132, 285, 344, 348;
as theory of knowledge, 295, 346;
and science, 346, 348;
and common sense, 347, 349;
problems of, 347.

Phosphenes, 58.

Physical science. _See_ Science.

Plato, 281.

Platonists, 349.

Pleasure, feeling of, 200;
recollection of, 264, 270.

Plutarch, 133, note[73].

Poetry, lyrical and dreams, 164;
misinterpretation of, 223;
personification, 224.

Points, discrimination of, 52.

Poisons, action of, 115.

Pollock, F., 184, note[101].

Pollock, W.H., 184.

Predisposition, action of, in perception, 44, 101, 102;
in æsthetic intuition, 215;
in insight, 223;
in recollection, 268;
in belief, 305, 319;
belief as, 324.

Prejudice. _See_ Predisposition.

Prenatal experience, recollection of, 281.

Preperception, 27;
illusions connected with, 44, 93;
voluntary, 95;
result of habit of mind, 101;
result of temporary conditions, 102;
as sub-expectation, 102;
as definite expectation, 106.

Presentation and representation, 9, 10, 13, 14, 192, 234, 329, 330.

Projection, outward, of sensations, 63;
of mental image, 111, 112;
of solid form on flat, 79, 81, 96.

Prophetic, dreams as, 129, 147, note[88];
enthusiast, 307.

Psychology, popular and scientific, 9, 10;
distinguished from philosophy, 14, 36, 345, 352;
introspective method of, 208;
as a kind of philosophy, 305.

Public events, localization, of, by memory, 258.

R.

Radestock, P., 130, note[71], 132, note[72], 134, note[75], 140, 141,
149, note[90], 162, 182, 275.

Rationalism, philosophic, 348.

Realism, 348.

Reality, nature of, 36, 346.

Recognition, and perception, 24, 25;
illusions of, 87;
and memory, 234.

Reflection (of light), illusions connected with, 73, 83.

Refraction and optical illusion, 73.

Relative, sensation as, 64;
attention to magnitude and brightness as, 91;
estimate of duration as, 249.

Relief, illusory perception of, 75, 96.

Representation and presentation, 9, 10, 13, 14, 192.

Retrospection. _See_ Memory.

Ribot, T., 238, note[114], 290, note[135].

Richter, J.P., 143.

Robertson, Professor G.C., 35, note[14].

Romanes, G.J., 105, note[2], 250, note[122].

Rousseau, 280.

S.

Savage, dream theory of, 128;
idea of nature of, 225.

Scherner, C.A., 140, 149.

Schopenhauer, A., 145, 342.

Schroeder, H., 85.

Science, philosophy and, 8, 36, 285, 344;
conception of the material world in physical, 36, 343, 346, 347;
and common cognition, 338, 357.

Scott, Sir W., 116, 125.

Secondary qualities, 36, 344.

Selection, process of, in perception, 95;
in dreams, 174;
in memory, 257, 263.

Self, confusion of, in dreams, 163;
introspective knowledge of, 192;
self-deception, 200;
identity of, 241, 282, 285;
confusion of present and past, 267, 284;
disturbances in recognition of, 287, 289;
momentary confusions of, 295;
confusion of present and future, 305.

Self-esteem, illusion of, 315;
origin of, 319;
utility of, 342.

Self-preservation, 320.

Sensation, element in perception, 20;
discrimination and classification of, 21;
interpretation of, 22;
inattention to, 39, 87;
modified by central reaction, 39, 87, 89, 91;
confusion of novel, 40;
indistinct, 41;
misinterpretation of, 44;
relation of, to stimulus, 46, 50;
limits to discrimination of, 52;
after-impression, 55;
subjective, 59, 62, 107, 143;
localization of, 59.

Sensibility, limits of, 50;
variations of, 64.

Sensualism, philosophic, 348.

Shadow, cast, 77.

Shakespeare, 3.

Sight, mode of perception, 19, 33, 34, 48, 49;
local discrimination in, 52;
single vision, 54;
localization of impression in, 60;
in sleep, 139;
images of, in sleep, 150, 154.

Single, vision, 54;
touch, 72.

Sleep, mystery of, 127;
physiology of, 131.

Sleight of hand. _See_ Conjuror.

Smell, as mode of perception, 34, note[14];
localization of impression in, 60;
subjective sensations of, 108;
in sleep, 141;
and taste, 171.

Solidity, illusory perception of, 75, 96.

Space, representation of, 207.

Specific energy of nerves, 58.

Spectra, ocular, etc. _See_ Subjective sensation.

Spencer, Herbert, 32, note[12], 128, note[69], 323, 340.

Spinoza, 143, 184.

Spiritualist _séances_, 103, 107, 123, 265.

Stereoscope, 75.

Stewart, Dugald, 172, 306.

Stimulus, qualitative relation of, to sensations, 46, 58, 67;
quantitative relation of, to sensation, 50, 64;
after-effect of, 55;
prolonged action of, 56;
subjective or internal, 62;
exceptional relation of, to organ, 70;
action of, in sleep, 135, 139, 143;
in hypnotic condition, 186.

Strümpell, L., 144, 147, note[89].

Subjective, experience, 26, 27, 137, 214;
movement, 51, 57;
sensation, 59, 62, 107, 113, 121, 143.

Suggestion, by external circumstances, 30, 44, 89, 91, 267;
verbal, 30, 106, 188, 215, 268, 301, 310.

Symbol, dream as, 129, 149.

Sympathy, basis of knowledge, 223;
and illusion of insight, 223;
and illusion of memory, 277;
and momentary illusion, 293.

T.

Taine, H., 60, note[29], 108, note[54], 117, note[59], 137,
298, note[137], 356, note[158].

Taste, æsthetic. _See_ Æsthetic intuition.

Taste, localization of impression in, 60;
subjective sensations of, 63;
variations in sensibility, 68;
activity of, in sleep, 141;
and smell, 171.

Temperament, a factor in sense-illusion, 101;
in dreams, 137;
in illusory belief, 325;
in illusion generally, 334, note[149].

Temperature, sense of, 65.

Tennyson, A., 226.

Testa, A.J., 131.

Testimony, of consciousness, 205;
fallacies of, 265;
to identity, 267.

Thaumatrope, 56.

Theatre, illusion of the, 104, 222;
self-deception of the actor, 200.

Thompson, Professor S.P., 51, note[17].

Thought, in relation to belief, 326.

Time, retrospective idea of, 239, 246, 250;
constant error in estimate of, 245;
subjective estimate of, 249;
contemporaneous estimate of, 250;
sense of, in insanity, 290;
prospective estimate of, 303.

Touch, as form of perception, 33, 34, 49;
local discrimination in, 52;
subjective sensations of, 62;
variations in sensibility of, 65;
in sleep, 141.

Transformation, in perception, 94;
of images in dreams, 163;
in memory, 262, 267;
in expectation, 305.

Trick. _See_ Conjuror.

Tuke, Dr., 110.

Tylor, E.B., 128, note[69].

U.

Unconscious, inference, 22, 68, 269, 335, note[150];
mental activity, 133, 235;
impressions, 41, 152.

Useful. _See_ Beneficial.

V.

Vanity. _See_ Self-esteem.

Venn, J., 299, note[139].

Ventriloquism, 82.

Verification, of sense-impression, 38, 351;
of self-inspection, 210;
of memory, 291.

Verisimilitude, in art, 80, 88;
in theatrical representation, 104;
in dreams, 168.

Vierordt, 245.

Vision. _See_ Sight.

Visions, 1, 110;
dreams regarded as, 128, 131.

Vital sense. _See_ Coenæsthesis.

Voice, internal, 119, 194;
activity of, in dreams, 155.

Volition, and perception, 95;
absence of, during sleep, 137,172;
co-operation of, in correction, of illusion, 352.

Volkelt, J., 172.

W.

Weber, E.H., 43.

Weinhold, Professor, 186.

Wetness, perception of, 53.

Wheatstone, Sir C, 75.

Wheel of life, 56.

Will. _See_ Volition.

Wordsworth, W., 281.

World, our estimate of, 323, 326, 327;
scientific conception of material, 8, 36, 343, 344;
reality of external, 344-346, 349, 353, 355, 360.

Wundt, Professor, W. 13, note[2], 31, note[11], 32, note[12], 58,
note[27], 67, note[34], 75, 93, note[47], 118, note[63], 136,
note[77], 139, 143, 177, 246, 247, note[119], 251, 252, 254.

THE END

FOOTNOTES:

[1] A history of the distinction is given by Brierre de Boismont, in his work _On Illusions_ (translated by R. T. Hulme, 1859). He says that Arnold (1806) first defined hallucination, and distinguished it from illusion. Esquirol, in his work, _Des Maladies Mentales_ (1838), may be said to have fixed the distinction. (See Hunt's translation, 1845, p. 111.)

[2] This fact has been fully recognized by writers on the pathology of the subject; for example, Griesinger, _Mental Pathology and Therapeutics_ (London, 1867), p. 84; Baillarger, article, "Des Hallucinations," in the _Mémoires de l'Académie Royale de Médecine_, tom. xii. p. 273, etc; Wundt, _Physiologische Psychologie_, p. 653.

[3] I here touch on the distinction between the psychological and the philosophical view of perception, to be brought out more fully by-and-by.

[4] It might even be urged that the order here adopted is scientifically the best, since sense-perception is the earliest form of knowledge, introspected facts being known only in relation to perceived facts. But if the mind's knowledge of its own states is thus later in time, it is earlier in the logical order, that is to say, it is the most strictly presentative form of knowledge.

[5] Here and elsewhere I use the word "impression" for the whole complex of sensation which is present at the moment. It may, perhaps, not be unnecessary to add that, in employing this term, I am making no assumption about the independent existence of external objects.

[6] Psychological usage has now pretty well substituted the term "image" for "idea," in order to indicate an individual (as distinguished from a general) representation of a sensation or percept. It might, perhaps, be desirable to go further in this process of differentiating language, and to distinguish between a sensational image, _e.g._ the representation of a colour, and a perceptional image, as the representation of a coloured object. It may be well to add that, in speaking of a fusion of an image and a sensation, I do not mean that the former exists apart for a single instant. The term "fusion" is used figuratively to describe the union of the two sides or aspects of a complete percept.

[7] This impulse to fill in visual elements not actually present is strikingly illustrated in people's difficulty in recognizing the gap in the field of vision answering to the insensitive "blind" spot on the retina. (See Helmholtz, _Physiologische Optik_, p. 573, _et seq._)

[8] This relation will be more fully discussed under the head of "Memory."

[9] I adopt this distinction from Dr. J. Hughlings Jackson. See his articles, "On Affections of Speech from Diseases of the Brain," in _Brain_, Nos. iii. and vii. The second stage might conveniently be named apperception, but for the special philosophical associations of the term: _Problems of Life and Mind_, third series, p. 107. This writer employs the word "preperception" to denote this effect of previous perception.

[10] Such verbal suggestion, moreover, acting through a sense-impression, has something of that vividness of effect which belongs to all excitation of mental images by external stimuli.

[11] See Wundt, _Physiologische Psychologie_, p. 723.

[12] For a confirmation of the view adopted in the text, see Professor Bain, _The Senses and the Intellect_, Part II. ch. i. sec. 8; Herbert Spencer, _Principles of Psychology_, vol. i. p. 234, _et passim_; Dr. Ferrier, _The Functions of the Brain_, p. 258, _et seq._; Professor Wundt, _op. cit._, pp. 644, 645; G. H. Lowes, _Problems of Life and Mind_, vol. v. p. 445, _et seq._ For an opposite view, see Dr. Carpenter, _Mental Physiology_, fourth edit., p. 220, etc.; Dr. Maudsley, _The Physiology of Mind_, ch. v. p. 259, etc.

[13] See note, p. 22.

[14] Touch gives much by way of interpretation only when an individual object, for example a man's hat, is recognized by aid of this sense alone, in which case the perception distinctly involves the reproduction of a complete visual percept. I may add that the organ of smell comes next to that of hearing, with respect both to the range and definiteness of its simultaneous sensations, and to the amount of information furnished by these. A rough sense of distance as well as of direction is clearly obtainable by means of this organ. There seems to me no reason why an animal endowed with fine olfactory sensibility, and capable of an analytic separation of sense elements, should not gain a rough perception of an external order much more complete than our auditory perception, which is necessarily so fragmentary. This supposition appears, indeed, to be the necessary complement to the idea first broached, so far as I am aware, by Professor Croom Robertson, that to such animals, visual perception consists in a reference to a system of muscular feelings defined and bounded by strong olfactory sensations, rather than by tactual sensations as in our case.

[15] It may be said, perhaps, that the exceptional direction of attention, by giving an unusual intensity to the impression, causes us to exaggerate it just as in the case of a novel sensation. An effort of attention directed to any of our vague bodily sensations easily leads us to magnify its cause. A similar confusion may arise even in direct vision, when the objects are looked at in a dim light, through a want of proper accommodation. (See Sir D. Brewster, _op. cit._, letter i)

[16] They might also be distinguished as objective and subjective illusions, or as illusions _a posteriori_ and illusions _a priori_.

[17] _Die Schein-Bewegungen_, von Professor Dr. J.I. Hoppe (1879); _cf._ an ingenious article on "Optical Illusions of Motion," by Professor Silvanus P. Thompson, in _Brain_, October, 1880. These illusions frequently involve the co-operation of some preconception or expectation. For example, the apparent movement of a train when we are watching it and expecting it to move, involves both an element of sense-impression and of imagination. It is possible that the illusion of table-turning rests on the same basis, the table-turner being unaware of the fact of exerting a certain amount of muscular force, and vividly expecting a movement of the object.

[18] _Physiologische Optik_, p. 316.

[19] It is plain that this supposed error could only be brought under our definition of illusion by extending the latter, so as to include sense-perceptions which are contradicted by reason employing idealized elements of sense-impression, which, as Lewes has shown (_Problems of Life and Mind_, i. p. 260), make up the "extra-sensible world" of science.

[20] An ingenious writer, M. Binet, has tried to prove that the fusion of homogeneous sensations, having little difference of local colour, is an illustration of this principle. (See the _Revue Philosophique_, September, 1880.)

[21] Even the fusion of elementary sensations of colour, on the hypothesis of Young and Helmholtz, in a seemingly simple sensation may be explained to some extent by these circumstances, more especially the identity of local interpretation.

[22] The perception of lustre as a single quality seems to illustrate a like error. There is good reason to suppose that this impression arises through, a difference of brightness in the two retinal images due to the regularly reflected light. And so when this inequality of retinal impression is imitated, as it may easily be by combining a black and a white surface in a stereoscope, we imagine that we are looking at one lustrous surface. (See Helmholtz, _Physiologische Optik_, p. 782, etc., and _Populäre wissenschaftliche Vorträge_, 2tes Heft, p. 80.)

[23] The conditions of the production of these double images have been accurately determined by Helmholtz, who shows that the coalescence of impressions takes place whenever the object is so situated in the field of vision as to make it practically necessary that it should be recognized as one.

[24] These illusions are, of course, due in part to inattention, since close critical scrutiny is often sufficient to dispel them. They are also largely promoted by a preconception that the event is going to happen in a particular way. But of this more further on. I may add that the late Professor Clifford has argued ingeniously against the idea of the world being a continuum, by extending this idea of the wheel of life. (See _Lectures and Essays_, i. p. 112, _et seq._)

[25] It is supposed that in the case of every sense-organ there is always some minimum forces of stimulus at work, the effect of which on our consciousness is _nil_.

[26] See Helmholtz, _Physiologische Optik_, p. 603. Helmholtz's explanation is criticised by Dr. Hoppe, in the work already referred to (sec. vii), though I cannot see that his own theory of these movements is essentially different. The apparent movement of objects in vertigo, or giddiness, is probably due to the loss, through a physical cause, of the impressions made by the pressure of the fluid contents of the ear on the auditory fibres, by which the sense of equilibrium and of rotation is usually received. (See Ferrier, _Functions of the Brain_, pp. 60, 61.)

[27] I do not need here to go into the question whether, as Johannes Müller assumed, this is an original attribute of nerve-structure, or whether, as Wundt suggests, it is due simply to the fact that certain kinds of nervous fibre have, in the course of evolution, been slowly adapted to one kind of stimulus.

[28] I here refer to what is commonly supposed to be the vague innate difference of sensation according to the local origin, before this is rendered precise, and added to by experience and association.

[29] The illusory character of this simple mode of perception is seen best, perhaps, in the curious habit into which we fall of referring a sensation of contact or discomfort to the edge of the teeth, the hair, and the other insentient structures, and even to anything customarily attached to the sentient surface, as dress, a pen, graving tool, etc. On these curious illusions, see Lotze, _Mikrokosmus_, third edit., vol. ii. p. 202, etc.; Taine, _De l'Intelligence_, tom. ii. p. 83, _et seq._

[30] Quoted by G.H. Lewes, _Problems of Life and Mind_, third series, p. 335. These illusions are supposed to involve an excitation of the nerve-fibres (whether sensory or motor) which run to the muscles and yield the so-called muscular sensations.

[31] It is brought out by Griesinger (_loc. cit._) and the other writers on the pathology of illusion already quoted, that in the case of subjective sensations of touch, taste, and smell, no sharp line can be drawn between illusion and hallucination.

[32] For a fuller account of these pathological disturbances of sensibility, see Griesinger; also Dr. A. Mayer, _Die Sinnestäuschungen_.

[33] Helmholtz, _op. cit._, p. 600, _et seq._ These facts seem to point to the conclusion that at least some of the feelings by which we know that we are expending muscular energy are connected with the initial stage of the outgoing nervous process in the motor centres. In other pathological conditions the sense of weight by the muscles of the arms is similarly confused.

[34] Wundt (_Physiologische Psychologie_, p. 653) would exclude from illusions all those errors of sense-perception which have their foundation in the normal structure and function of the organs of sense. Thus, he would exclude the effects of colour-contrast, _e.g._ the apparent modification of two colours in, juxtaposition towards their common boundary, which probably arises (according to E. Hering) from some mutual influence of the temporary state of activity of adjacent retinal elements. To me, however, these appear to be illusions, since they may be brought under the head of wrong _interpretations_ of sense-impressions. When we see a grey patch as rose-red, as though it were so independently of the action of the complementary light previously or simultaneously, that is to say, as though it would appear rose-red to an eye independently of this action, we surely misinterpret.

[35] Quoted by G.H. Lewes, _loc. cit._, p. 257.

[36] The subject of the perception of movement is too intricate to be dealt with fully here. I have only touched on it so far as necessary to illustrate our general principle. For a fuller treatment of the subject, see the work of Dr. Hoppe, already referred to.

[37] The perception of magnitude is closely connected with that of distance, and is similarly apt to take an illusory form. I need only refer to the well-known simple optical contrivances for increasing the apparent magnitude of objects. I ought, perhaps, to add that I do not profess to give a complete account of optical illusions here, but only to select a few prominent varieties, with a view to illustrate general principles of illusion. For a fuller account of the various mechanical arrangements for producing optical illusion, I must refer the reader to the writings of Sir D. Brewster and Helmholtz.

[38] Painters are well aware that the colours at the red end of the spectrum are apt to appear as advancing, while those of the violet end are known as retiring. The appearance of relief given by a gilded pattern on a dark blue as ground, is in part referable to the principle just referred to. In addition, it appears to involve a difference in the action of the muscles of accommodation in the successive adaptations of the eye to the most refrangible and the least refrangible rays. (See Brücke, _Die Physiologie der Farben_, sec. 17.)

[39] Helmholtz tells us (_Populäre wissenschaftliche Vorträge_, 3tes Heft, p. 64) that even in a stereoscopic arrangement the presence of a wrong cast shadow sufficed to disturb the illusion.

[40] Among the means of giving a vivid sense of depth to a picture, emphasized by Helmholtz, is diminishing magnitude. It is obvious that the perceptions of real magnitude and distance are mutually involved. When, for example, a picture represents a receding series of objects, as animals, trees, or buildings, the sense of the third dimension, is rendered much more clear.

[41] A striking example of this was given in a painting, by Andsell, of a sportsman in the act of shooting, exhibited in the Royal Academy in 1879.

[42] This is at least true of all near objects.

[43] Helmholtz remarks _(op. cit._, p. 628) that the difficulty of seeing the convex cast as concave is probably due to the presence of the cast shadow. This has, no doubt, some effect: yet the consideration urged in the text appears to me to be the most important one.

[44] _Populäre wissenschaftliche Vorträge_, 3tes Heft, pp. 71, 72.

[45] See, on this point, some excellent remarks by G.H. Lewes, _Problems of Life and Mind_, third series, vol. ii. p. 275.

[46] To some extent this applies to the changes of apparent magnitude due to altered position. Thus, we do not attend to the reduction of the height of a small object which we are wont to handle, when it is placed far below the level of the eye. And hence the error people make in judging of the point in the wall or skirting which a hat will reach when placed on the ground.

[47] I refer to the experiments made by Exner, Wundt, and others, in determining the time elapsing between the giving of a signal to a person and the execution of a movement in response. "It is found," says Wundt, "by these experiments that the exact moment at which a sense-impression is perceived depends on the amount of preparatory self-accommodation of attention." (See Wundt, _Physiologische Psychologie_, ch. xix., especially p. 735. _et seq._)

[48] Quoted by Helmholtz, _op. cit._, p. 626.

[49] When the drawing, by its adherence to the laws of perspective, does not powerfully determine the eye to see it in one way rather than in the other (as in Figs. 5 to 7), the disposition to see the one form rather than the other points to differences in the frequency of the original forms in our daily experience. At the same time, it is to be observed that, after looking at the drawing for a time under each aspect, the suggestion now of the one and now of the other forces itself on the mind in a curious and unaccountable way.

[50] _Ueber die phantastischen Gesichsterscheinungen_, p. 45.

[51] Another side of histrionic illusion, the reading of the imitated feelings into the actors' minds, will be dealt with in a later chapter.

[52] In a finished painting of any size this preparation is hardly necessary. In these cases, in spite of the great deviations from truth in pictorial representation already touched on, the amount of essential agreement is so large and so powerful in its effect that even an intelligent animal will experience an illusion. Mr. Romanes sends me an interesting account of a dog, that had never been accustomed to pictures, having been put into a state of great excitement by the introduction of a portrait into a room, on a level with his eye. It is not at all improbable that the lower animals, even when sane, are frequently the subjects of slight illusion. That animals dream is a fact which is observed as long ago as the age of Lucretius.

[53] This kind of illusion is probably facilitated by the fact that the eye is often performing slight movements without any clear consciousness of them. See what was said about the limits of sensibility, p. 50.

[54] _Mental Physiology_, fourth edit., p. 158.

[55] In persons of very lively imagination the mere representation of an object or event may suffice to bring about such a semblance of sensation. Thus, M. Taine (_op. cit._, vol. i. p. 94) vouches for the assertion that "one of the most exact and lucid of modern novelists," when working out in his imagination the poisoning of one of his fictitious characters, had so vivid a gustatory sensation of arsenic that he was attacked by a violent fit of indigestion.

[56] Mentioned by Dr. Carpenter (_Mental Physiology_, p. 207), where other curious examples are to be found.

[57] See _Annales Médico-Psychologiques_, tom. vi. p. 168, etc.; tom. vii. p. 1. etc.

[58] I have already touched on the resonance of a sense-impression when the stimulus has ceased to act (see p. 55). The remarks in the text hold good of all such after-impressions, in so far as they take the form of fully developed percepts. A good example is the recurrence of the images of microscopic preparations, to which the anatomist is liable. (See Lewes, _Problems of Life and Mind_, third series, vol. ii. p. 299.) Since a complete hallucination is supposed to involve the peripheral regions of the nerve, the mere fact of shutting the eye would not, it is clear, serve as a test of the origin of the illusion.

[59] That subjective sensation may become the starting-point in complete hallucination is shown in a curious instance given by Lazarus, and quoted by Taine, _op. cit._, vol. i. p. 122, _et seq._ The German psychologist relates that, on one occasion in Switzerland, after gazing for some time on a chain of snow-peaks, he saw an apparition of an absent friend, looking like a corpse. He goes on to explain that this phantom was the product of an image of recollection which somehow managed to combine itself with the (positive) after-image left by the impression of the snow-surface.

[60] For an account of Mr. Galton's researches, see _Mind_, No. xix. Compare, however, Professor Bain's judicious observations on these results in the next number of _Mind_. The liability of children to take images for percepts, is illustrated by the experiences related in a curious little work, _Visions_, by E.H. Clarke, M.D. (Boston, U.S., 1878), pp. 17, 46, and 212.

[61] A common way of describing the relation of the hallucinatory to real objects, is to say that the former appear partly to cover and hide the latter.

[62] Griesinger remarks that the forms of the hallucinations of the insane rarely depend on sense-disturbances alone. Though these are often the starting-point, it is the whole mental complexion of the time which gives the direction to the imagination. The common experience of seeing rats and mice running about during a fit of _delirium tremens_ very well illustrates the co-operation of peripheral impressions not usually attended to, and possibly magnified by the morbid state of sensibility of the time (in this case flying spots, _muscæ volitantes_), with emotional conditions. (See Griesinger, _loc. cit._, p. 96.)

[63] Wundt (_Physiologische Psychologie_, p. 652) tells us of an insane woodman who saw logs of wood on all hands in front of the real objects.

[64] It is stated by Baillarger (Mémoires de l'Académie Royale de Médicine, tom. xii. p. 273, etc.) that while visual hallucinations are more frequent than auditory in healthy life, the reverse relation holds in disease. At the same time, Griesinger remarks (_loc. cit._, p. 98) that visual hallucinations are rather more common than auditory in disease also. This is what we should expect from the number of subjective sensations connected with the peripheral organ of vision. The greater relative frequency of auditory hallucinations in disease, if made out, would seem to depend on the close connection between articulate sounds and the higher centres of intelligence, which centres are naturally the first to be thrown out of working order. It is possible, moreover, that auditory hallucinations are quite as common as visual in states of comparative health, though more easily overlooked. Professor Huxley relates that he is liable to auditory though not to visual hallucinations. (See _Elementary Lessons in Physiology_, p. 267.)

[65] See Baillarger, _Mémoires de l'Académie Royale de Médicine_, tom. xii. p. 273, _et seq._

[66] See Baillarger, _Annales Médico-Psychologiques_, tom. vi. p. 168 _et seq._; also tom. xii. p. 273, _et seq._ Compare Griesinger, _op. cit._ In a curious work entitled _Du Démon de Socrate_ (Paris, 1856), M. Lélut seeks to prove that the philosopher's admonitory voice was an incipient auditory hallucination symptomic of a nascent stage of mental alienation.

[67] This is well brought out by Dr. J. Hughlings Jackson, in the papers in _Brain_, already referred to.

[68] _Friend_, vol. i. p. 248. The story is referred to by Sir W. Scott in his _Demonology and Witchcraft_.

[69] See E.B. Tylor, _Primitive Culture_, ch. xi.; _cf._ Herbert Spencer, _Principles of Sociology_, ch. x.

[70] For a fuller account of the different modes of dream-interpretation, see my article "Dream," in the ninth edition of the _Encyclopædia Britannica_.

[71] For a fuller account of the reaction of dreams on waking consciousness, see Paul Radestock, _Schlaf und Traum_. The subject is touched on later, under the Illusions of Memory.

[72] For an account of the latest physiological hypotheses as to the proximate cause of sleep, see Radestock, _op. cit._, appendix.

[73] Plutarch, Locke, and others give instances of people who never dreamt. Lessing asserted of himself that he never knew what it was to dream.

[74] The error touched on here will be fully dealt with under Illusions of Memory.

[75] For a very full, fair, and thoughtful discussion of this whole question, see Radestock, _op. cit._, ch. iv.

[76] This may be technically expressed by saying that the liminal intensity (Schwelle) is raised during sleep.

[77] See Wundt, _Physiologische Psychologie_, pp. 188-191.

[78] There is, indeed, sometimes an undertone of critical reflection, which is sufficient to produce a feeling of uncertainty and bewilderment, and in very rare cases to amount to a vague consciousness that the mental experience is a dream.

[79] _Observations on Man_, Part I. ch. iii, sec. 5.

[80] Quoted by Radestock, _op. cit._, p. 110.

[81] _Le Sommeil et les Rêves_, p. 132, _et seq._

[82] _Das Leben des Traumes_, p. 369. Other instances are related by Beattie and Abercrombie.

[83] _Le Sommeil et les Rêves_, p. 42, _et seq._

[84] _Beiträge sur Physiognosie und Heautognosie_, p. 256. For other cases see H. Meyer, _Physiologie der Nervenfaser_, p. 309; and Strümpell, _Die Natur und Entstehung der Träume_, p. 125.

[85] A very clear and full account of these organic sensations, or common sensations, has recently appeared from the pen of A. Horwicz in the _Vierteljahrsschrift für wissenschaftliche Philosophie_, iv. Jahrgang 3tes Heft.

[86] Schopenhauer uses this hypothesis in order to account for the apparent reality of dream-illusions. He thinks these internal sensations may be transformed by the "intuitive function" of the brain (by means of the "forms" of space, time, etc.) into quasi-realities, just as well as the subjective sensations of light, sound, etc., which arise in the organs of sense in the absence of external stimuli. (See _Versuch über das Geisterschen: Werke_, vol. v. p. 244, _et seq._)

[87] _Das Alpdrücken_, pp. 8, 9, 27.

[88] It is this fact which justifies writers in assigning a prognostic character to dreams.

[89] A part of the apparent exaggeration in our dream-experiences may be retrospective, and due to the effect of the impression of wonder which they leave behind them. (See Strümpell, _Die Natur und Entstehung der Träume_.)

[90] _Cf._ Radestock, _op. cit._, pp. 131, 132.

[91] I was on one occasion able to observe this process going on in the transition from waking to sleeping. I partly fell asleep when suffering from toothache. Instantly the successive throbs of pain transformed themselves into a sequence of visible movements, which I can only vaguely describe as the forward strides of some menacing adversary.

[92] Even the "unconscious impressions" of waking hours, that is to say, those impressions which are so fugitive as to leave no psychical trace behind, may thus rise into the clear light of consciousness during sleep. Maury relates a curious dream of his own, in which there appeared a figure that seemed quite strange to him, though he afterwards found that he must have been in the habit of meeting the original in a street through which he was accustomed to walk (_loc. cit._, p. 124).

[93] See p. 53.

[94] See Maury, _loc. cit._, p. 146.

[95] See what was said respecting the influence of a dominant emotional agitation on the interpretation of actual sense-impressions.

[96] It is proved experimentally that the ear has a much closer organic connection with the vocal organ than the eye has. Donders found that the period required for responding vocally to a sound-signal is less than that required for responding in the same way to a light-signal.

[97] On the nature of this impulse, as illustrated in waking and in sleep, see the article by Delboeuf, "Le Sommeil et les Rêves," in the _Revue Philosophique_, June, 1880, p. 636.

[98] _Physiologische Psychologie_, p. 660.

[99] I may, perhaps, observe, after giving two dreams which have to do with mathematical operations, that, though I was very fond of them in my college days, I have long ceased to occupy myself with these processes. I would add, by way of redeeming my dream-intelligence from a deserved charge of silliness, that I once performed a respectable intellectual feat when asleep. I put together the riddle, "What might a wooden ship say when her side was stove in? Tremendous!" (Tree-mend-us). I was aware of having tried to improve on the form of this pun. I am happy to say I am not given to punning during waking life, though I had a fit of it once. It strikes me that punning, consisting as it does essentially of overlooking sense and attending to sound, is just such a debased kind of intellectual activity as one might look for in sleep.

[100] See Radestock, _op. cit._, ch. ix.; _Vergleichung des Traumes mit dem Wahnsinn_.

[101] For Spinoza's experience, given in his own words, see Mr. F. Pollock's _Spinoza_, p. 57; _cf._ what Wundt says on his experience, _Physiologische Psychologie_, p. 648, footnote 2.

[102] See an interesting account of "Recent Researches on Hypnotism," by G. Stanley Hall, in _Mind_, January, 1881.

[103] I need hardly observe that physiology shows that there is no separation of different elementary colour-sensations which are locally identical.

[104] This kind of error is, of course, common to all kinds of cognition, in so far as they involve comparison. Thus, the presence of the excitement of the emotion of wonder at the sight of an unusually large object, say a mountain, disposes the mind to look on it as the largest of its class. Such illusions come midway between presentative and representative illusions. They might, perhaps, be specially marked off as illusions of "judgment."

[105] So far as any mental state, though originating in a fusion of elements, is now unanalyzable by the best effort of attention, we must of course regard it in its present form as simple. This distinction between what is simple or complex in its present nature, and what is originally so, is sometimes overlooked by psychologists. Whether the feelings and ideas here referred to are now simple or complex, cannot, I think, yet be very certainly determined. To take the idea of space, I find that after practice I recognize the ingredient of muscular feeling much better than I did at first. And this exactly answers to Helmholtz's contention that elementary sensations as partial tones can be detected after practice. Such separate recognition may be said to depend on correct representation. On the other hand, it must be allowed that there is room for the intuitionist to say that the associationist is here reading something into the idea which does not belong to it. It is to be added that the illusion which the associationist commonly seeks to fasten on his opponent is that of confusing final with original simplicity. Thus, he says that, though the idea of space may now to all intents and purposes be simple, it was really built up out of many distinct elements. More will be said on the relation of questions of nature and genesis further on.

[106] I may as well be frank and say that I myself, assuming free-will to be an illusion, have tried to trace the various threads of influence which have contributed to its remarkable vitality. (See _Sensation and Intuition_, ch. v., "The Genesis of the Free-Will Doctrine.")

[107] I purposely leave aside here the philosophical question, whether the knowledge of others' feelings is intuitive in the sense of being altogether independent of experience, and the manifestation of a fundamental belief. The inherited power referred to in the text might, of course, be viewed as a transmitted result of ancestral experience.

[108] I here assume, along with G.H. Lewes and other competent dramatic critics, that the actor does not and dares not feel what he expresses, at least not in the perfectly spontaneous way, and in the same measure in which he appears to feel it.

[109] The illusory nature of much of this emotional interpretation of music has been ably exposed by Mr. Gurney. (See _The Power of Sound_, p. 345, _et seq._)

[110] The reader will note that this impulse is complementary to the other impulse to view all mental states as analogous to impressions produced by external things, on which I touched in the last chapter.

[111] Errors of memory have sometimes been called "fallacies," as, for example, by Dr. Carpenter (_Human Physiology_, ch. x.). While preferring the term "illusion," I would not forget to acknowledge my indebtedness to Dr. Carpenter, who first set me seriously to consider the subject of mnemonic error.

[112] From this it would appear to follow that, so far as a percept is representative, recollection must be re-representative.

[113] The relation of memory to recognition is very well discussed by M. Delboeuf, in connection with a definition of memory given by Descartes. (See the article "Le Sommeil et les Rêves," in the _Revue Philosophique_, April, 1880, p. 428, _et seq._)

[114] A very interesting account of the most recent physiological theory of memory is to be found in a series of articles, bearing the title, "La Mémoire comme fait biologique," published in the _Revue Philosophique_, from the pen of the editor, M. Th. Ribot. (See especially the _Revue_ of May, 1880, pp. 516, _et seq._) M. Ribot speaks of the modification of particular nerve-elements as "the static base" of memory, and of the formation of nerve-connections by means of which the modified element may be re-excited to activity as "the dynamic base of memory" (p. 535).

[115] What constitutes the difference between such a progressive and a retrogressive movement is a point that will be considered by-and-by.

[116] It is not easy to say how far exceptional conditions may serve to reinstate the seemingly forgotten past. Yet the experiences of dreamers and of those who have been recalled to consciousness after partial drowning, whatever they may prove with respect to the revivability of remote experiences, do not lead us to imagine that the range of our definitely localizing memory is a wide one.

[117] _Der Zeitsinn nach Versuchen_, p. 36, _et seq._

[118] _Physiologische Psychologie_, p. 782.

[119] Wundt refers these errors to variations in the state of preadjustment of the attention to impressions and representations, according as they succeed one another slowly or rapidly. There is little doubt that the effects of the state of tension of the apparatus of attention, are involved here, though I am disposed to think that Wundt makes too much of this circumstance. (See _Physiologische Psychologie_, pp. 782, 783. I have given a fuller account of Wundt's theory in _Mind_, No. i.)

[120] Strictly speaking, it would occupy more time, since the effort of recalling each successive link in the chain would involve a greater interval between any two images than that between the corresponding experiences.

[121] I need hardly say that there is no sharp distinction between these two modes of subjective appreciation. Our estimate of an interval as it passes is really made up of a number of renewed anticipations and recollections of the successive experiences. Yet we can say broadly that this is a prospective estimate, while that which is formed when the period has quite expired must be altogether retrospective.

[122] See an interesting paper on "Consciousness of Time," by Mr. G. J. Romanes, in _Mind_ (July, 1878).

[123] It is well known that there is, from the first, a gradual falling off in the strength of a sensation of light when a moderately bright object is looked at.

[124] _Cf._ Hartley, _Observations on Man_, Part I. ch. iii. sec. 4 (fifth edit., p. 391).

[125] See Dr. Carpenter's _Mental Physiology_, fourth edit, p. 456.

[126] This is, perhaps, what is meant by saying that people recall their past enjoyments more readily than their sufferings. Yet much seems to turn on temperament and emotional peculiarities. (For a fuller discussion of the point, see my _Pessimism_, p. 344.)

[127] The only exception to this that I can think of is to be found in the power which I, at least, possess, after looking at a new object, of representing it as a familiar one. Yet this may be explained by saying that in the case of every object which is clearly apprehended there must be vague revivals of _similar_ objects perceived before. Oases in which recent experiences tend, owing to their peculiar nature, very rapidly to assume the appearance of old events, will be considered presently.

[128] _Mental Physiology_, p. 456.

[129] _Mental Physiology_, second edit., p. 172.

[130] _Loc. cit._, p. 390.

[131] This source of error has not escaped the notice of autobiographers themselves. See the remarks of Goethe in the opening passages of his _Wahrheit und Dichtung_.

[132] One wonders whether those persons who, in consequence of an injury to their brain, periodically pass from a normal into an abnormal condition of mind, in each of which there is little or no memory of the contents of the other state, complete their idea of personal continuity in each state by the same kind of process as that described in the text.