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.
[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 Désordres
Généraux de la Mémoire," 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-même."
[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_, 2ième 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 _Première Méditation_ 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_, 2ième 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 Müller and the
"nativistic school." (See my exposition and criticism of these doctrines
in _Mind_, April, 1878, pp. 168-178 and 193-195.)