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require spatial images for the clear apprehension of our feelings,
yet what these images express is not the feeling, but its occasion
or its effect. The idea of joy consists, for most people, in the idea
of something cheerful and smiling. But the more intense the
emotion, the more it suppresses all such symbolic images. In every
feeling there is something inexpressible, incommensurable with
any expression. The feelings drive us to search for forms and
expressions, but are not themselves arranged in the form of
space. If in a dejected mood there gleams a ray of hope,
we do not set it above or below, to the right or the left, of the
dejection, as with simultaneous sensations of different colours.
Different elements of consciousness may thus be experienced
simultaneously, without being arranged in the form of space. The
want of clearness and difficulty of immediate psychological per-
ception are in a measure connected with this (see p. 22). We lack a
form of intuition for simultaneous internal phenomena, while for
simultaneous external phenomena we possess one.

6. We apprehend space in three dimensions ; up and clown, left
and right, forwards and backwards. These three may be reduced
to two : to distance (or depth) and superficial extension.

It will easily be seen that the apprehension of distance cannot
owe its origin to any single sensation. Every sensation pre-
supposes, psychologically, that a physical excitation reaches the
sense-organ. But distance does not in itself make any physical
impression upon us. We measure distance by a line from the
object to us ; but no excitation can directly inform us of the
existence of this line. The line denotes the direction of the excita-
tion, but does not itself give rise to a sensation. We can apprehend
distance only by in some way or other measuring out such aline :
but this measuring is no single sensation, but a process of com-
parison, which either already involves a certain idea of space or
else is grounded on the degrees and kinds of sensation^ which we
have when we approach the object or move a part of our body
towards it.

We do in fact thus measure out by movement, whenever v/e
apprehend an object {cf. p. 119). The eye involuntarily accommo-
dates itself so that the excitation of light may fall on the yellow
spot of the retina. The lens becomes more convex, the nearer the
object is to us. The two eyes are so placed, that the visual axes


converge more or less, according to the distance of that which
attracts the attention : if I look at a near object, my eyes ars
turned inwards (by means of the muscles attached to the inner
side) ; if I then turn my gaze to the distance, my eyes are
turned outwards (by means of the outer muscles of the eyes).
We grasp at an object, or move towards it, in order to touch it.
In these several ways we receive motor-sensations, which are
definitely connected with the position of the object relatively to
us. With the appearance or feel of the object comes then to be
connected, by association or habit, the reproduction of the motor-
sensations, a necessary presupposition to the most distinct appre-
hension of the object. More or less clearly, distance signifies
to us the greater or smaller series of motor-sensations, which
we have because our sense-organs (especially the organs of sight
and touch) are moved so as to receive the most distinct excita-
tions possible,^ or which we should have if we moved from our
standpoint to the object. It agrees with this, that the appre-
hension of distance is clear and plain only in the case of near
objects, and that in the case of distinct objects it is the plainer the
more familiar they arc to us. The very plainest apprehension of
space is obtained from what we have directly measured with
our own hands. Greater distances (like greater portions of time)
are understood only symbolically, being regarded as a sum of
smaller distances directly measurable.

The sense of touch and the motor-sensations linked with its
activity, are the original basis of the apprehension of distance.
We take the true measure of an object by actively feeling it. The
distances thus learned, we always mentally read into our visual
apprehension. Distant objects, which seem small to sight, we
estimate immediately according to the size they would appear
to the sense of touch. Then, but in a secondary way only, the
size of known objects as presented to sight, becomes in its turn
a means of estimating their distance.

This theory, first propounded by ^cr^Qley- {Theory 0/ Vision,
Dublin, 1709), is partially confirmed by observations on new-born
infants and on persons blind from birth who have recovered their

1 As Strieker (Stmiu-n ilbcr die Assozicition dcr Vorstelltingen, ^\'ien, 1SS3, p. 56)
has observed that \vc have such motor-sensations even when, with our eyes shut, we pass
from the idea of something distant to the idea of sometliing very near. We notice that
something takes place in the eye.

- Berkeley, liowever, does not lay so much stress on the motor-sensations, as we have in
the above exposition. Bain and Spencer have especially brought out the force of the
motor-sensations in the apprehension o'f space. — Hclmholtz and Wundt have carried the
theory further.


sight. Although a child turns very early towards the light, it
scarcely apprehends distance so soon. The movements of the two
eyes are as a rule not co-ordinated, so that the visual axes do not
at first always meet in the point which is the object of apprehen-
sion, and that they should do so would be an indispensable pre-
supposition, were the apprehension of distance to depend upon an
innate mechanism, coming at once into activity.^ Only gradually
(in the course of the first three months) is practice in co-ordinating
the eyes obtained, and squinting no longer frequent. And even
after accommodation has been acquired, the secure apprehension of
distance is wanting, as appears from the fact that the child grasps
after things which are out of reach. Even in the second and third
years, the estimation of distance is imperfect.^

Even in later years the combined action of the two eyes is not
quite harmonious. With practice we may obtain double images of
objects. This is most easily effected by fixing the gaze on a point
in the back-ground of the field of vision while attending to an
object lying in a straight line in front of the point ; this object will
then be seen doubled.^

It is not quite certain, whether it is the same with new-born
animals as with human beings. Spalding's* experiments with
chickens just hatched, and with pigs just born, show that these
animals are at once able to find their food with great certainty.
The chickens run quickly to the corn or to an insect,^ and the
pigs to their mother's teats. A young pig which was placed
on a chair, ten minutes after the bandage which had been over
its eyes from birth was removed, appeared to measure the dis-
tance to the ground, knelt down and jumped off. — This might
seem to show an immediate apprehension of distance ; but we
must be on our guard against attributing too much importance

1 Descartes had already subscribed to this view, maintained in our times by the so-called
"nativism." Descartes allowed, however, in the immediate apprehension of
distance, however simple it might appear, there yet lay involved a comparison
(ratiocinatio involuta, similis illi, qua geometrae per duas stationes diversas loca inaccessa
dimetiuntur. — Dioptrica. ch. 5, § 13). Here is at once implied the theory of unconscious
inferences, and that certainly not by an empiricist, but by a nativist.

- Preyer, Die SecU des Kindes, pp. 24—29, 38, seq. 112. (Eng. trans, i. 34-41, so,sej.,

i* [See Bernstein, 131, 132. (Tr.)]

4 Spalding put a little hood over the head of his chickens as soon as they crept out of
the egg, and before they had made use of their visual power. He kept them thus for two
days, until they were able to move about. (Romanes, Mental Evolution in Animals,
p. 161, seg.)

5 It had been already observed by Adam Smith (" On the External Senses " in his
Essays on Philosophical Subjects, edited by Dugald Stewart), that this sure knowledge
of surroundings immediately after birth is only found in birds which build their nests on
Uvel ground, not in those which build in trees and in other less accessible places.


to these facts, for it is conceivable that an immediate in-
stinct comes into play, which, under the guidance of sensations
of sight, of smell, or of hearing, leads the animal to its food,
and something similar may be the case as regards the jumping.
It is scarcely, therefore, permissible to postulate an actual
(tpprelicftsion of distance before experience and practice, even
though the course of education may in this, as in so many other
respects, be much shorter for the animal than for man. Even
with respect to man, the ease and speed with which the apprehen-
sion of distance is developed, is scarcely to be explained without
supposing that inherited tendencies and powers play a part. The
sensations, by combination of which the apprehension of distance
is conditioned, are more familiar to the individual if they have
played an important part in the course of the evolution of the
whole race.

The experiences of the blind from birth who have recovered
their sight likewise exhibit features, which bear out the theory
founded by Berkeley. The blind man operated on by Cheselden
(1728) was, after recovering his sight, so incapable of judging dis-
tances, that he thought all objects " touched his eyes " (as he
himself expressed it), just as that which he felt touched his hand.
The patient operated on by Fran/. (1S40) apprehended a cube as a
square, a sphere as a disk, and a pyramid as a triangle ; he came to
understand these things only by the sense of touch. Everything
looked to him perfectly flat. Dufour's patient (1876) could not
judge of distances without help of the hands. He went with his
hands stretched out in front of him to the shining door-latch, to
which his attention had been directed, but came to a stop two steps
away from it, and made several vain attempts before he succeeded
in laying hold of it. — If it is said, with respect to this last example,
that any one who moves towards an object must have an idea of
its distance, this is an unwarranted inference. It is only necessary
so to direct the movement, that the guiding visual sensation does
not lose, but gradually gains, in strength, and this involves no idea
of distance. There is a game, in which an object has to be found
with the help of music, the music growing louder as the object is
approached, softer as it is left in the distance. In this it is evident
that the persons searching are guided by no apprehension of dis-
tance ; the movement is immediately regulated by the force of the

If the view now presented is right, the apprehension of distance

O 2


results from association between the sensations and representations
of sight, of touch, and of movement. This association is supported
by an innate and inherited basis, which in the case of many
animals may perhaps be so perfectly developed that the influence
of experience plays only a subordinate part, but which does not
seem, in the case of man, to exclude the necessity of a course
of experience, so to practise that association that it may become
indissoluble and to give to the apprehension of distance the stamp
of an immediate and simple act of sense. This is a cla^ssical
instance of "psychical chemistry" (\\ B. St/). If we think that
we immediately "see" distances, it is only in the same sense that
we "see" joy immediately in a man's countenance.

7. (<^) In respect also of superficial extension, the attempt has
been made to explain the apprehension of space through asso-
ciation of visual sensations with representations of touch and
movement. What is immediately apprehended would then be com-
posed of sensations of a certain quality, and the apprehension of
space would result from the fusing of these with certain representa-
tions. It is natural to believe, and the belief is confirmed by obser-
vations of new-born infants, that sight at first embraces only light
and colours. The excitations which are clear and bright, but not too
dazzling, are sought out and the endeavour made to retain them ;
it is only later that the form of the object is apprehended.^ Through
percepts and experiments made with touch and by the movement
of one or several organs, the limits of individual objects come to be
known to us. The language of the visual sense becomes perfectly
plain only by means of sensations of movement and touch. On the
other hand, sight, when once it has developed hand in hand with
the above-named senses, plays quite the greatest part in our appre-
hension of space. There now arises the question, whether the
blind, who are confined to sensations of touch and movement, do
actually have an intuition of space similar to that of persons with
sight. We, who can see, conceive of space as a visible surface at
a little distance from us ; but how can a blind man actually picture
to himself space ? — Here appears the real paradox involved in
saying that space is a psychological product. For if the exclusion
of the visual images leaves only a something which is not the same
in kind as visible space, we shall not be able to say what space is
in itself, since in this case no definition can be given which will

i According to Preyer(pp. 36, 41) (Rng. trans. i)p. 42, 52), a chilJ's seeing is in the first
few days only an obscure sense of bright and dark.


serve for botli the visual and the tactual space. There would
then be no more natural connection between the visual space and
the tactual space, than between the name and the things denoted
by it.

There is actually to be had a definite observation on this point.
Ernst Plainer writes in his Philosophischcn Aphorismen ;^ "As
regards the idea of space or extension ac([uircd without sight,
the observation and examination of a person blind from birth, which
I have carried on for three weeks, have more than ever convinced
me that the sense of feeling (touch) is in itself absolutely ignorant of
what pertains to extension and space, and knows nothing of a local
separation between things. I am convinced, in brief, that the sight-
less man perceives absolutely nothing of the external world, except
the existence of something acting, which may be distinguished from
the feeling of self (general sensation) suffering it, and for the rest
merely the numerical difference— shall I say of impressions or of
things .'' In reality to the blind, time serves instead of space. Near-
ness and distance mean to them nothing more, than the shorter or
longer time, the smaller or greater number of feelings [sensations],
which he requires, in order to get from one feeling [sensation] to
another. The fact that the blind person employs the language of
sight, may very well deceive, and did deceive me when I first
began my investigations ; but in reality he knows nothing of things
as outside one another, and (this especially I have observed very
plainly), if the objects and the different parts of the body with
which they come in contact did not make different kinds of im-
pressions on the sensory-nerves, he would regard everything ex-
ternal as one thing, that acts successively upon him, e.g., more
strongly when he places his hand on a surface than when he
lays a finger on it, more faintly still when he strokes a surface
with his hand or passes the foot over it. In his own body he
distinguishes between head and feet not in the least by distance,
but merely by the incredible fineness with which he can recognize
differences in the feelings [sensations] experienced in the one or
the other of these parts, and also by time. In the same way he
distinguishes the form of other bodies purely by the kinds of the
feelings [impressions on the sense of touch], since, e.g., a cube,
through its corners and sides, affects the sense of feeling (touch)
differently from a sphere."

We have an approximation to the space-perception of the blind,

1 Leipzig, 1793, p. 466, seq.


when we try to find our way in a dark room. Only we have the
advantage, that the visual space lies ready in the background, and
may be brought to our assistance in the interpretation of the
sensations of touch and movement. It is something similar when
we concentrate attention on the tongue and— with the visual
sensations as far as possible discounted— observe what apprehen-
sion of space it affords us. For the tongue is like a blind man, and
yet has an excellent acquaintance with its surroundings.

{b) However, there still remains a possible way of maintaining
the originality of the apprehension of space. Motor-sensations are,
indeed, always successive ; but by means of the sense of touch we
can receive several impressions simultaneously. In like manner
several rays of light may fall simultaneously upon the retina.
Now may not this afford the possibility of an immediate appre-
hension of the excitations as arranged in space? It might seem
even necessary to suppose this. For sensation of a colour really
means sensation of a coloured surface ; if the coloured object
were only a mathematical point, it would afford no excitation.
Even if larger objects are apprehended only through movement of
the organs of sight and touch, it might still be thought that small
objects could be apprehended immediately, without successive
process. There must be an immediate distinction between the
impression of a shilling and that of a threepenny bit. The appre-
hension of small surfaces would then be the minimum, to which
" nativism," the theory which maintains the originality of the
apprehension of space, would be reduced, the final stronghold from
which it could not be expelled.^

It cannot, of course, be denied, that we may receive and con-

1 Cf. Stumvf, DerPsyc/w!o^-/sc/ic i/?-j-/r7^«^rt'fr/:'a?»«™?-i/f//««^(" The Psychological
Origin of the Idea of Space,") Leipzig, 1873, p. 56— 71.— Professor Mahaffy of Duhhn
gave an account, in a letter in Mmd, i83i, p. 278, s^y., of an interview with the blind
man cured by Franz. This man, a doctor in Kingstown, declared that he saw and
distinguished forms immediately after receiving sight, and that outlines and forms were
as the sense of touch had led liim to expect. Mahaffy regarded this as the testimiony of
a competent judge in favour of the originality of the power to distinguish form through
sight alone. But neither this interpretation nor the facts of the case accord with the
report of Dr. Franz given shortly after the operation, in Philosophical 1 ransactions,
(1841) As mentioned above, the patient perceived a cube as a square, and a sphere as a
circle When Franz begged him to describe the impressions which the objects made on
him he said that he noticed at once a difference between the cube and_ the square, but was
unable to form the idea of a square or of a disk, until he had felt in his finger-tips a
.sensation, as if he really touched the objects (/'////. Traus., 1841, 1, p. 65). He had
thus to make an actual translation of the language of the one .sense into that ot the
other before he could recognize forms. There remains in favour of nativism, only the
fact that he at once noticed a difference in the forms. But even in this the experience of
the s«-se of touch may have helped. His attitude towards the forms was not that of a
consciousness without any experience ; not, that is to say, the attitude of the earhest


tinually retain a host of simultaneous sensations of light and
contact, and that we perceive them immediately as arranged in
space. On the other hand, it is not so certain that the earliest
consciousness has the same perception. A great variety of
simultaneous impressions will at first take effect rather as a col-
lective mass, will yield one single chaotic sensation. And as the
quality and the strength of the impression cannot be at once
distinguished, so also the space-relation cannot be from the first
apprehended in its own right, but would so to speak conceal itself
in a higher degree of strength, or, to make use of Bain's expression,
in a greater massiveness of the impression. The account quoted
from Platner points in this direction, for it shows that only
qualitative differences of impression induced the blind patient to
recognize diverse phenomena distinct from self. Reference may
also be made in this connection to AVebcr's experiments, which
proved that the degree of warmth seems higher when the whole
hand is immersed in warm water, than when the finger only is
immersed. As it cannot be supposed that there is an innate idea
of the difference between the fingers and the hand, this difference
in strength would be at first the only thing apparent.

A purely passive apprehension of simultaneously given im-
pressions can only be momentary. The activity is at once
excited, the eye moves along the surface, or the hand touches
it. At once, then, simultaneity passes into succession, the in-
tuition becomes discursive. We apprehend moving objects more
quickly and easily than objects at rest, "knd when the objects do
not move, we move relatively to them. Two successive excitations
on the skin can be distinguished with a smaller distance between
them than two simultaneous excitations. The lowest animals and
new-born infants do not notice any simultaneous differences in
their surroundings, while they can apprehend successive dit'fer-
ences (changes) {cf. p. 114). By movement things are discovered
and apprehended, which would otherwise remain unnoticed. The
first chaotic sensation will consequently be determined by a scries
of succeeding sensations, in which from the nature of the case the
motor-sensations take a prominent place.

It might even be maintained, that successive and discursive
apprehension is a necessary presupposition of true apprehension of
space. Space signifies a relation. By something being in space is
meant, that it occupies a certain position in relation to other things,
and that its several parts occupy certain positions relatively to onQ


another. Instead of speaking of space in general as an integral
unity, it is better to make use of the more elementary conception
" position." It is then apparent, that the apprehension of space
rests on a comparison or a combination. It cannot therefore
subsist as given from the first, but presupposes a certain psycho-
logical activity.

{c) It is not a matter of indifference, which part of the body
meets with an excitation from the external world. As it is by
successive experiences that we learn to know our own body, as
well as the world surrounding us, it cannot be supposed that
we can originally know or feel on which part an excitation lights.
If, then, the excitations do, nevertheless, act differently on the
different parts, this difference can appear to consciousness only as a
certain shade, a qualitative side-determination of the sensation.
The special character which the sensation receives, from the fact
of the excitation lighting upon one single definite point, Lotze calls
its local sign. The conditions are different at every point of the skin
and of the retina ; there must therefore be a variety of local signs.
As regards sight, these local signs may consist either in the motor-
impulses, different for each point, which aim at turning the eye so
that the excitation of light may fall on the yellow spot (Lotze), or
in the different quality of the sensations at the different parts of the
retina (Wundt). In respect of the sense of touch Lotze finds the
local signs given in the different secondary sensations, which one
and the same touch produces by reason of the difference in thick-
ness and tightness of the skin and the different underlayers which
it encloses at different points.^

Let us suppose that the excitation A falls upon a point in the
retina at some distance from the yellow spot, and that it then
attracts our attention. The eye will then be moved in such a way
that A will fall upon the yellow spot. Answering to this move-
ment, there will be a motor-sensation, which we shall call tt. Now
let A on another occasion fall upon a different point in the retina,

Online LibraryHarald HøffdingOutlines of psychology → online text (page 22 of 41)