This question would seem to be most directly answerable by an appeal to individual testimony. Viewed in this light, it is a question for the present, for some few already allege that in their case philosophic reasonings exercise an appreciable effect on these beliefs. And so far as this is so, the man of scientific temper will feel that there is a question for him.

It is evident, however, that the question of the persistence of these fundamental beliefs is much more one for the future than for the present. The correction of a clearly detected illusion is, as I have more than once remarked, a slow process. An illusion such as the apparent movement of the sun will persist as a partially developed error long after it has been convicted. And it may be that the fundamental beliefs here referred to, even if presumably illusory, are destined to exercise their spell for long ages yet.

Whether this will be the case or not, whether these intuitive beliefs are destined slowly to decay and be dissolved as time rolls on, or whether they will retain an eternal youth, is a question which we of to-day seem, on a first view of the matter, to have no way of answering which does not assume the very point in question—the truth or falsity of the belief. This much may, however, be said. The associationist who resolves these erroneous intuitions into the play of association, admits that the forces at work generating and consolidating the illusory belief are constant and permanent forces, and such as are not likely to be less effective in the future than they have been in the past. Thus, he teaches that the intuition of the single object in the act of perception owes its strength to "inseparable association," according to which law the ideas of the separate "possibilities of sensation," which are all we know of the object, coalesce in the shape of an idea of a single uniting substance. He adds, perhaps, that heredity has tended, and will still tend, to fix the habit of thus transforming an actual multiplicity into an imaginary unity. And in thus arguing, he is allowing that the illusion is one which, to say the least of it, it will always be exceedingly difficult for reason to dislodge.

In view of this uncertainty, and of the possibility, if not the probability, of these beliefs remaining as they have remained, at least approximately universal, the man of science will probably be disposed to hold himself indifferently to the question. He will be inclined to say, "What does it matter whether you call such an apparently permanent belief the correlative of a reality or an illusion? Does it make any practical difference whether a universal 'intuition,' of which we cannot rid ourselves, be described as a uniformly recurring fiction of the imagination, or an integral constitutive factor of intelligence? And, in considering the historical aspect of the question, does it not come to much the same thing whether such permanent mental products be spoken of as the attenuated forms or ghostly survivals of more substantial primitive illusions (for example, anthropomorphic representations of material objects, 'animistic' representations of mind and personality), or as the slowly perfected results of intellectual evolution?"

This attitude of the scientific mind towards philosophic problems will be confirmed when it is seen that those who seek to resolve stable common convictions into illusions are forced, by their very mode of demonstration, to allow these intuitions a measure of validity. Thus, the ideas of the unity and externality attributed to the object in the act of perception are said by the associationist to answer to a matter of fact, namely, the permanent coexistence of certain possibilities of sensation, and the dependence of the single sensations of the individual on the presence of the most permanent of these possibilities, namely, those of the active or muscular and passive sensations of touch, which are, moreover, by far the most constant for all minds. Similarly, the idea of a necessary connection between cause and effect, even if illusory in so far as it expresses an objective necessity, is allowed to be true as an expression of that uniformity of our experience which all scientific progress tends to illustrate more and more distinctly. And even the idea of a permanent self, as distinct from particular fugitive feelings, is admitted by the associationist to be correct in so far as it expresses the fact that mind is "a series of feelings which is aware of itself as past and future." In short, these "illusory intuitions," by the showing of those who affirm them to be illusory, are by no means hallucinations having no real object as their correlative, but merely illusions in the narrow sense, and illusions, moreover, in which the ratio of truth to error seems to be a large one.

It would thus appear that philosophy tends, after all, to unsettle what appear to be permanent convictions of the common mind and the presuppositions of science much less than is sometimes imagined. Our intuitions of external realities, our indestructible belief in the uniformity of nature, in the nexus of cause and effect, and so on, are, by the admission of all philosophers, at least partially and relatively true; that is to say, true in relation to certain features of our common experience. At the worst, they can only be called illusory as slightly misrepresenting the exact results of this experience. And even so, the misrepresentation must, by the very nature of the case, be practically insignificant. And so in full view of the subtleties of philosophic speculation, the man of science may still feel justified in regarding his standard of truth, a stable consensus of belief, as above suspicion.

Transcribers note: In the original some footnotes read 'note[1]'and 'note[2]'. They have been renumbered to allow readers to refer directly to the correct footnote.

INDEX.

A.

Abercrombie, Dr. J, 141, note[82], 278.

Abnormal life, relation of, to normal, 1, 120, 121, 124, 182, 277, 284, note[132], 336; effects of amputation, 62; modification of sensibility in, 65; gross sense-illusions of, 111, hallucinations of, 118; sense of personal identity in, 289.

Active, stage in perception, 27; illusion distinguished from passive, 45, 332-334.

Actor. See Theatre.

Adaptation, illusion as want of, 124, 188, 339.

AEsthetic intuition, 213; illusions of, 214.

After-dreams, 144, 183.

After-sensation, after-impression, 55, 115.

Anaesthesia, 65.

Ancestral experience, results of, 281.

Animals, recognition of portraits by, 105; expectation of, 298.

Anthropomorphism, 225, 360.

Anticipation. See Expectation.

Apparitions. See Hallucination.

Aristotle, 130.

Art, illusions of, 77, 104.

Artemidoros, 129.

Association, laws of, in perception, 22; in dreams, 153, 156; link of resemblance in dreams, 159; associative dispositions in dreams, 169; effect of, in insight, 221; inseparable, 359.

Associationist, views of, 349, 352, 355.

Attention, involved in perception 21; absence of, in sense-illusion, 39, 87; relation of, to recognition of objects, 90; expectant, 93; attitude of, in dreaming, 137, 172; to internal mental states, 194; absence of, in errors of insight, 228.

Authority, influence of, in introspection, 210; in belief, 325.

Autobiography, errors connected with, 276, 280.

Automatic activity of centres, in hallucinations, 113; in dreams, 136, 151; automatic intellectual processes, 300, 335, 352.

B.

Baillarger, J., 13, note[1], 113, note[57], 119, notes[64] and [65], 120, note[66].

Bain, Dr. A., 32, note[12], 117, note[60], 190.

Beattie, J., 141, note[82].

Beauty, sentiment of, 206, 213.

Belief, immediate, 14, 15, 294; simple and compound, 296; illusory forms of, 297; simple expectation, 297; expectation, of extra-personal experiences, 307; retrospective, 309; in persistent objects and persons, 312; self-esteem, 315; representation of classes of things, 322; representations of mankind, 322; representation of life and the world as a whole, 322; as predisposition to error, 324; amount of divergence in, 325; tendency towards convergence in, 326.

Beneficial, correct knowledge as, 340; illusion as, 342.

Berkeley, Bishop, 218, 349, note[154].

Binet, A., 53, note[20].

Boismont, Brierre de, 11, note[1].

Boerner, J., 146.

Braid, James, 186, 187.

Brewster, Sir D., 42, 73, 81, 116.

Bruecke, E., 77, note[38].

Byron, Lord, 116.

C.

Carpenter, Dr. W.B., 32, note[12], 108, 110, note[56], 186, 231, note[111], 265, note[125], 276.

Castle-building, as illusory perception, 3, 99.

Cause, idea of, in science, 344; reality of relation of, 347, 349, 356, 360.

Change, a condition of conscious life, 252, 287, note[133].

Childhood, our recollections of, 263, 269.

Children, curiosity of, 175, 180; estimate of time by, 256; confusion of dream and waking life by, 276; imagination of, 279; self-assertion of, 319; intellectual condition of, 357, note[159].

Clarke, Dr. E.H., 117.

Classification, in recognition of sensation, 21; in recognition, of object, 24; in introspective recognition, 193.

Clifford, Professor W.K., 56, note[24].

Coalescence, of sensations, 43, 52; of dream-images, 162; of internal feelings, 196; of mnemonic images, 265.

Coenaesthesis, 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 aesthetic 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].

Hyperaesthesia, 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.

Lelut, 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.

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

Muscae 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.

Paraesthesia, 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 aesthetic 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 aesthetic 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 seances, 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.

Struempell, 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, aesthetic. See AEsthetic 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 Coenaesthesis.

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 Memoires de l'Academie Royale de Medecine, 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 Populaere wissenschaftliche Vortraege, 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 Mueller 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 Sinnestaeuschungen.

[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 Bruecke, Die Physiologie der Farben, sec. 17.)

[39] Helmholtz tells us (Populaere wissenschaftliche Vortraege, 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] Populaere wissenschaftliche Vortraege, 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 Medico-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, muscae 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 (Memoires de l'Academie Royale de Medicine, 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, Memoires de l'Academie Royale de Medicine, tom. xii. p. 273, et seq.

[66] See Baillarger, Annales Medico-Psychologiques, tom. vi. p. 168 et seq.; also tom. xii. p. 273, et seq. Compare Griesinger, op. cit. In a curious work entitled Du Demon de Socrate (Paris, 1856), M. Lelut 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 Encyclopaedia 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 Reves, p. 132, et seq.

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

[83] Le Sommeil et les Reves, p. 42, et seq.

[84] Beitraege sur Physiognosie und Heautognosie, p. 256. For other cases see H. Meyer, Physiologie der Nervenfaser, p. 309; and Struempell, Die Natur und Entstehung der Traeume, 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 fuer 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 ueber das Geisterschen: Werke, vol. v. p. 244, et seq.)

[87] Das Alpdruecken, 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 Struempell, Die Natur und Entstehung der Traeume.)

[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 Reves," 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 Reves," 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 Memoire 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.

[133] The reader will remark that this condition of clear intellectual consciousness, namely, a certain degree of similarity and continuity of character in our successive mental states, is complementary to the other condition, constant change, already referred to. It may, perhaps, be said that all clear consciousness lies between two extremes of excessive sameness and excessive difference.

[134] It follows that any great transformation of our environment may lead to a partial confusion with respect to self. For not only do great and violent changes in our surroundings beget profound changes in our feelings and ideas, but since the idea of self is under one of its aspects essentially that of a relation to not-self, any great revolution in the one term, will confuse the recognition of the other. This fact is expressed in the common expression that we "lose ourselves" when in unfamiliar surroundings, and the process of orientation, or "taking our bearings," fails.

[135] On these disturbances of memory and self-recognition in insanity, see Griesinger, op. cit., pp. 49-51; also Ribot, "Des Desordres Generaux de la Memoire," in the Revue Philosophique, August, 1880. It is related by Leuret (Fragments Psych. sur la Folie, p. 277) that a patient spoke of his former self as "la personne de moi-meme."

[136] In the following account of the process of belief and its errors, I am going over some of the ground traversed by my essay on Belief, its Varieties and Conditions ("Sensation and Intuition," ch. iv.). To this essay I must refer the reader for a fuller analysis of the subject.

[137] For an account of the difference of mechanism in memory and expectation, see Taine, De l'Intelligence, 2ieme partie, livre premier, ch. ii. sec. 6.

[138] J.S. Mill distinguishes expectation as a radically distinct mode of belief from memory, but does not bring out the contrast with respect to activity here emphasized (James Mill's Analysis of the Human Mind, edited by J.S. Mill, p. 411, etc.). For a fuller statement of my view of the relation of belief to action, as compared with that of Professor Bain, see my earlier work.

[139] For some good remarks on the logical aspects of future events as matters of fact, see Mr. Venn's Logic of Chance, ch. x.

[140] James Mill's Analysis of the Human Mind, edited by J.S. Mill, vol. i p. 414, et seq.

[141] Principles of Geology, ch. iii.

[142] To make this rough analysis more complete, I ought, perhaps, to include the effect of all the errors of introspection, memory, and spontaneous belief, into which the person himself falls, in so far as they communicate themselves to others.

[143] In the case of a vain woman thinking herself much more pretty than others think her, the error is still more obviously one connected with a belief in objective fact.

[144] The Study of Sociology, ch. ix.

[145] As a matter of fact, the proportion of accurate knowledge to error is far larger in the case of classes than of individuals. Propositions with general terms for subject are less liable to be faulty than propositions with singular terms for subject.

[146] For a description of each of these extremes of boundless gaiety and utter despondency, see Griesinger, op. cit., Bk. III. ch. i. and ii. The relation of pessimism to pathological conditions is familiar enough; less familiar is the relation of unrestrained optimism. Yet Griesinger writes that among the insane "boundless hilarity," with "a feeling of good fortune," and a general contentment with everything, is as frequent as depression and repining (see especially p. 281, also pp. 64, 65).

[147] It has been seen that, from a purely psychological point of view, even what looks at first like pure presentative cognition, as, for example, the recognition of a present feeling of the mind, involves an ingredient of representation.

[148] See especially what was said about the rationale of illusions of perception, pp. 37, 38.

[149] I say "usually," because, as we have seen, there may sometimes be a permanent and even an inherited predisposition to active illusion in the individual temperament and nervous organization.

[150] See what was said on the nature of passive illusions of sense (pp. 44, 68, 70, etc.) The logical character of illusion might be brought out by saying that it resembles the fallacy which is due to reasoning from an approximate generalization as though it were a universal truth. In thus identifying illusion and fallacy, I must not be understood to say that there is, strictly speaking, any such thing as an unconscious reasoning process. On the contrary, I hold that it is a contradiction to talk of any mental operation as altogether unconscious. I simply wish to show that, by a kind of fiction, illusion may be described as the result of a series of steps which, if separately unfolded to consciousness (as they no longer are), would correspond to those of a process of inference. The fact that illusion arises by a process of contraction out of conscious inference seems to justify this use of language, even apart from the fact that the nervous processes in the two cases are pretty certainly the same.

[151] If we turn from the region of physical to that of moral ideas, we see this historical collision between common and individual conviction in a yet more impressive form. The teacher of a new moral truth has again and again been set down to be an illusionist by a society which was itself under the sway of a long-reigning error. As George Eliot observes, "What we call illusions are often, in truth, a wider vision of past and present realities—a willing movement of a man's soul with the larger sweep of the world's forces."

[152] To make this account of the philosophic problem of the object-world complete, I ought to touch not only on the distinction between the vulgar and the scientific view of material things, but also on the distinction, within physical science, between the less and the more abstract view roughly represented by molar and molecular physics.

[153] For an excellent account of the distinction between the scientific and the philosophic point of view, see Mr. Shadworth Hodgson's Philosophy of Reflection, Bk. I. chs. i. and iii.; also Bk. III. chs. vii. and viii.

[154] I hold, in spite of Berkeley's endeavours to reconcile his position with that of common sense, that the popular view does at least tend in this direction. That is to say, the every-day habit, when considering the external world, of abstracting from particular minds, leads on insensibly to that complete detachment of it from mind in general which expresses itself in the first stage of philosophic reflection, crude realism. The physicist appears to me, both from the first essays in Greek "nature-philosophy," as also from the not infrequent confusion even to-day between a perfectly safe "scientific materialism" and a highly questionable philosophic materialism, to share in this tendency to take separate consideration for separate existence. Each new stage of abstraction in physical science gives birth to a new attempt to find an independent reality, a thing-in-itself, hidden further away from sense.

[155] See the interesting autobiographical record of the growth of philosophic doubt in the Premiere Meditation of Descartes.

[156] The appeal is not, as we have seen, invariably from sight to touch, but may be in the reverse direction, as in the recognition of the duality of the points of a pair of compasses, which seem one to the tactual sense.

[157] I might further remark that this "collective experience" includes previously detected illusions of ourselves and of others.

[158] M. Taine frankly teaches that what is commonly called accurate perception is a "true hallucination" (De l'Intelligence, 2ieme partie, Livre I. ch. i. sec. 3).

[159] It only seems to do so, apart from philosophic assumptions, in certain cases where experience testifies to a uniform untrustworthiness of the origin. For example, we may, on grounds of matter of fact and experience, be disposed to distrust any belief that we recognize as springing from an emotional source, from the mind's feelings and wishes.

I may add that a so-called intuitive belief may refer to a matter of fact which can be tested by the facts of experience and by scientific methods. Thus, for example, the old and now exploded form of the doctrine of innate ideas, which declared that children were born with certain ideas ready made, might be tested by observation of childhood, and reasoning from its general intellectual condition. The same applies to the physiological theories of space-perception, supposed to be based on Kant's doctrine, put forward in Germany by Johannes Mueller and the "nativistic school." (See my exposition and criticism of these doctrines in Mind, April, 1878, pp. 168-178 and 193-195.)

THE END