and the motor-sensation which will be similarly occasioned, will
also be different {K). We may then compare A -\- tt and A + A',
and the conscious difference, resulting from the difference in the
point on which the excitation has fallen, can now be apprehended.
Again, if the excitation j5 falls upon the same point in the retina as
previously A, it will be combined with the same motor-sensation.
1 Lotze lias given several accounts of his theory of local signs, the last in Crundzuge
der PsychnCogie (i88i). As regards Wundt, see Physiol. Psychol., ii, jjp. 25, 28, 163
(3rd ed. pp. 30-33, 191).
V] THE PSYCHOLOGY OF COGNITION 20i
Between A -\- n and B -\ - ir^ there will then be found a likeness
connected with the point in the retina concerned. — In this way a
consciousness corresponding to the local relations is gradually
framed.^
These local signs can at first take effect only by successive
apprehension. Consciousness cannot experience them all at once ;
only after the whole series has been gone through, can each of the
sensations with its local sign be assigned to its definite place. If
their determination is to be perfect, therefore, the local signs must
make up a connected system. Excitation of a single point on tlie
skin or the retina may then lead to a determination of locality, with-
out the whole scries of local signs being gone through afresh ;
for it is in this as in all cases where we have often gone through a
series of different sensations or ideas, as the result of practice, the
whole series comes at last to seem the object of an immediate
intuition or of an intuitive knowledge (c/. p. 163, sf^.).
8. But in spite of all this, the real apprehension of space is not yet
explained. We have obtained a coherent group of motor-sensations,
local signs, and sensations of light and contact, combined according
to the laws of association. But no arrangement of all this is yet
given, which would give rise to the intuition of an image, with its
several parts placed one outside the other, and it outside our self
(or rather outside the image of our organism) ; for all these sensa-
tions were qualitative and intensive, not extensive.-
Here it appears that all theories of the apprehension of space are
at a loss. The so-called " nativistic " theory regards the apprehension
of space as given with the very first impressions.-'' According to it,
all psychological explanation of the development of the apprehen-
sion of space is as superfluous as impossible ; the apprehension of
space must be accepted as a priori. But the experiments quoted
above (6, 7 a and b) seem to contradict this theory. IC\-cry iniper.
fection and every error in localization and apprehension of space
1 Cy! my treatise on " Lotze's Doctrine of Sp.-ice and Time," in Philosophische Monat-
schr. (1888), p. 126, seq. The Swedish writer, Reinhold Oeiger, had previously
(Philos. Monatscltr, 1888) pointed out gaps in Lotze's theory of local signs, which I
endeavour to fill up in the way above indicated. [The above paragraph and note are
inserted at Prof Hdffding's request. (Tr.)]
^[Cf., however, the later recognition of "extensity" or "extensivencss" (Bain's
" massiveness "> as a property of sensations, and the new turn consequently taken by
the discussion. (Dr. Ward in Ency. Jin'/, vol. xx., Art. "Psychology," pp. 53-55, and
Prof W. James's articles on the " Perception of Space," Mind, 1SS7.) (Tr,))
3 "I'he most important representatives of nativism are at the present day Stumpf, from
the side of psychology (ZJi'r /V>c/»(i/. Ursf>r. dcr Raumvorst.), Her ing from the side of
physiology (Ins last work is Dcr Uamitsinn und die Bewegungen des Alices, Hermann's
ilandbui.li, iii, i).
202 OUTLINES OF PSYCHOLOGY fv
really contradict it, while they are to be explained very easily if
the apprehension of space is itself a result of experience. For this
reason the genetic theory regards space as a psychological product,
caused by combination of intensive and qualitative sensations
according to the general psychological laws of the association of
ideas. But there still remains an unexplained residue, for the
psychological product has a property not possessed by the ele-
ments out of which it has arisen, that very property which gives
rise to the problem, namely, the extensive form. The attempt
has, indeed, been made to explain the transition from the apprehen-
sion of successive stimuli to the intuition of the extended, by
saying that the intuition of space forms of itself when it is
indifferent from which end we begin the reproduction of a series of
sensations ; for time has but one direction, space on the other hand
several. Ultimately the whole series would be presented to us at
once, wherever we might begin. But the utmost that we should
arrive at in this way, would be simultaneity in time (co-existence)
and not space. And a series of sounds may be repeated forwards
and backwards, without being arranged as simultaneous — or as
spatial. A transformation must therefore be admitted, a psychical
synthesis, analogous to the chemical synthesis, out of which arise
compound substances with properties not possessed by the ele-
ments {cf. p. 163). In this synthesis the visual sensations play, for
all who have sight, the most important part, and are the customary
language into which the contributions afforded by the other senses
are translated. — Whether a corresponding synthesis also takes
place for the blind, with the sense of touch in the ascendant, seems
from Platner's account to be doubtful.
Even if it were the case, that tangible and visible minima were
apprehended as extended, it would still be necessary to postulate a
synthesis. For our space-images are continuously, uninterruptedly
connected ; but neither the retina nor the surface of the skin
afford the basis of such a continuity. In the retina, there is even
a point quite impervious to excitations of light, the " blind spot,"
where the visual nerve enters the eye ; but there is no similar gap
in our visual image ; we thus involuntarily fill up the gaps in the
series of the sensations. Every theory, therefore, which does not
represent the apprehension of space as given from the first " at one
stroke," must in some form or other call in the constructive power
of consciousness.
Such an appeal is not without its dangers. To a psychological
V] THE PSYCHOLOGY OF COGNITION 203
conception, which finds the essential character of consciousness
expressed in synthesis, in the bringing together into unity and con-
nection (II. 5. V. B. 5), it might seem highly probable that this
fundamental form should be repeated in the separate mental
processes. But it is one thing to hit upon the true characteristic
of consciousness as a whole, quite another to utilize the said
characteristic as a detis ex viachina in special psychological pro-
blems. An opening might thus be easily afforded to arbitrary
judgments ; into such a psychical synthesis anything might be
read. For this reason Lotze sets to work with the utmost circum-
spection, maintaining that his theory of local signs is not intended
to explain the actual apprehension of space, but only the motives
and aids of the mind when it gives shape to its spatial images.
That the mind forms spatial images in the first instance out of
certain of its sensations, Lotze regards on the other hand as a
capacity which must be accepted as a fact, or as an impulse which
is open to no further explanation.
The genetic theory is then only in complete opposition to the
nativistic, when it goes so far as to hold that all the conditions
for the development of the apprehension of space are given in
the experiences of the single individual. This view is, how-
ever, improbable, on account of the unexplained residue which
remains over, when we compare the elementary sensations with
the fully developed apprehension of space. If in the synthesis
to which this owes its definitive origin, we recognize the expression
of a constructive power operating instinctively, then the question
as to the origin of this power will refer us from the single in-
dividual back to the system of nature within which it takes its
rise. The experiences which cannot lead to the given end in an
individual life-time, may during the evolution of the race have
gradually led to such an accommodation of the organization that
inherited dispositions supplement what is insufficient in the in-
dividual experiences. The evolution hypothesis, first applied to
this province by Herbert Spencer (1855), affords the prospect of
tracing the problem farther back than was possible while psychology
was confined to the experiences of the individual life.
How close the genetic and nativistic theories may approach
is to be seen from the fact that, while on the one side it is
allowed that the immediately given knowledge of space may be
infinitely small as compared with what is added by association,
and that in the original sensations there is really given only a
204 OUTLINES OF PSYCHOLOGY [v
possibilily of definite apprehension of space (Stumpf), on the other
side it is intimated that everything may be so prepared in the
organism, that the time between the first excitation of hght on
the retina and the origin of the idea of space may become infinitely
small (Wundt).i
9. But whether the "nativistic " or the genetic theory is adopted,
it remains a necessary presupposition for the apprehension of space,
that a definite organic basis should be present. The conflict of
theories concerns, or should concern, only the point, whether the
functions conditioned by the organization come at once into action
or require a preparation and practice of a certain duration.
To give the more exact account of the organic structures which
are of importance to the origination of the apprehension of space,
is the business of the physiology of the senses.^ Here reference
will only be made, in addition to what has been already implied,
to the importance of the central mechanism, which makes a close
association between the sense-stimuli and the muscular movements
of the sense organs possible. As regards the sense of touch the
optic thalmniis, as regards sight the corpora quadrigemina, seem
to be the centres through which this association, and with it the
physiological expression of the psychological synthesis, is accom-
plished ; but the cerebrum probably plays a part also.
The apparatus thus lying ready is perhaps able with some animals
(,cf. 6) to function immediately after birth, so that the experiences
necessary to the apprehension of space are at once and easily
gained. With human beings, as it seems, several months elapse
before so much is attained.
10. So far we have spoken of the actual form of space and of the
faculty of intuiting spatial images. As to the idea of space, as a
general, or rather as a typical individual idea, this is evolved
1 Stumpf, Der Psychologische Ursfrung der Ramnvorsielliiiig {" 'ihc Psychological
Origin of the Idea of Space "), p. 114, seg., 184. — Wundt, Physiol. Psychol., ii., p. 164
(3rded., p. 207, seq.). Cf. also Spencer, Principles of Psycholog') ii., p. 203, seq.
- See in this connection, Panum, Sanserne og tie Vilknariige Pez'dgclser {" "The
Senses and Voluntary Movements "), pp. 234-238; and Wundt's very full account (ii.,
chaps. II & 13). — In the above investigations only the most important psychological
points of view are taken into consideration. We must refer any one who wishes to enter
into the special psychological and physiological questions opened up by the theory of the
apprehension of space, to Wundt's work, where the whole material is to be found
collected and critically treated. — The question whether the axioms of geometry are
based on our faculty of intuition as determined by our organization, or whether with
sufficient practice we could form an idea of, and clearly describe, space with other
proijerties, comes under epistemology, not under psychology. From the qnirely logical
point of view, such a possibility cannot of course be disputed, but as a matter of fact, we
are restricted to our space as characterized by the a.xionis of Kuclid's geometry, until
our organization shall have sustained a change by accommodation to other conditions of
existence.
v] THE PSYCHOLOGY OF COGNITION 205
in the same way as the idea of time (i — 3), by the attention being
directed to the schema common to all individual spatial images,
and to its possible expansion. At first the idea of space is limited.
The patient operated on by Chesclden, could not picture to himself
lines in space extending beyond the- limits of his visual orbit.
He knew that the room he was in was only part of the house, but
could not grasp the fact that the whole house might look larger than
the room. The power of applying the individual ideas symbolically,
was still wanting. When this power is developed, it is discovered
that no limits can be set to the subdivision or to the expansion
of space, any more than of time.
The infinity of space (as of time) signifies that every limit of
space is accidental, and can be overstepped in imagination.
Absolute space, all the points and parts of which are perfectly
homogeneous and continuous and which has no space beyond it,
is a mathematical abstraction without a counterpart in psycho-
logical intuition. Psychological space is relative ; it presupposes
certain points of reference as given, and its parts do not appear
with strict continuity and homogeneousness. In our apprehension
of space, we make always greater or smaller leaps (as, e.g., in
letting the eye stray from one point to another), and the difference
in content gives to each part of space a certain qualitative difference
in our apprehension and intuition.
D. — The Apprehension of Things as Real.
1. Sensations, ideas, and concepts are forms under which the
cognitive elements of the conscious content appear and are
arranged. We have traced this arrangement from its simplest
stage in the interaction of sensations, up to its highest stage in
the activity of thought and of imagination directed to definite
problems. The governing laws were essentially the same
throughout. The motive of the advance from an involuntary
arrangement in the play of sensations and ideas to scientific
thought and artistic imagination, lay in the criticism necessarily
brought in with growing experience. Fresh differences and con-
trasts require fresh activity, that the connection and the unity may
be maintained and chaos overcome. The logical principles and
the a-sthetic rules, though it is not the business of psychology to
lay them down, develop, nevertheless, according to natural psycho-
logical laws and prove thereby their intimate connection with
2o6 OUTLINES OF PSYCHOLOGY [v
human nature ; they do not make their appearance abruptly as
something externally imposed.
But here the question arises, how is it that, in the content of its
sensations and ideas and in the connection given to this content
by the activity of thought, consciousness recognizes a reality in-
dependent of itself? It does not follow, because our knowledge
develops according to definite psychological laws of nature, that
it leads to a reality. The phantasies of the insane and dream-
images are equally subject to psychological laws, and for that reason
we have often been able to employ them as aids in our inquiries.
How, then, is it made manifest to consciousness, that it has in its
content a reality and no dream ? Can some definite activity-
perception or act of thought — be indicated, through which we are
led to believe that we have before us a reality ?
It is not only at the standpoint of highly developed conscious-
ness that this question comes up. It is really incessantly presented
from the very beginning of consciousness. It is not permitted to
the individual to arrange his ideas as he likes. There is carried
on a constant education through disappointments, which may be
hard and painful {cf. V. B. 4). The first disappointment affords the
first basis of the contrast between the possible and the real, or
between dream and reality.— We are here recurring to this point,
in order to carry the train of thought further.
2. The impulse to movement, so early stirring in conscious
beings, leads them involuntarily to make inroads into nature.
They soon find, however, that their movements may not proceed
unchecked. At certain points they encounter resistance, and in
the sensation of resistance, of prevented movement, the individual
finds a something foreign, something which is not itself — whatever
else it may be. He may perhaps repeat the attempt to overcome
resistance ; but in this he will never wholly succeed. Fresh barriers
are always substituted for those set aside.
Looked at in one way, every one of the special sensations is a
sensation of resistance. Every physical excitation takes effect
only when it reaches the outer surface of the organism, prin-
cipally those parts of it, in which the receptivity for the special
species of excitation is most developed (as the eye for rays of
light, the ear for waves of air, etc.). But just on account of their
delicacy, the special senses play no great part in the development
of the belief in a reality. They co-operate, but presuppose a firm
nucleus round which they may gather, and this nucleus is given in
V] THE PSYCHOLOGY OF COGNITION 207
the sensation of a resistance against our movement. A being whu
had sensations of sight, hearing, smell, taste, and touch only, would
lead as it were an ethereal existence, would stand outside the
tangible reality. The very word object signifies resistance ; object
is that which is thrown against us (or as in the German Gegen-
stand, which stands against us).
Reliance can, however, be placed in no single percept, whatever
it may be. We have seen that the percept is always complex,
since in it fresh sensations blend immediately with memories. This
contains the source of a multitude of illusions, which arise through
false interpretation of the given sensations {B. ya). Perception is
an attempt at interpretation ; but how is the correctness of the
interpretation to be guaranteed .-' Sensations may call up incorrect
memories. Moreover, the brain may be put by processes within
the organism in a state similar to that which arises when
excitations reach it from the external world. There then result
hallucinations, false sensations and percepts, which can often not be
distinguished from normal sensuous percepts. Not only sight, but
the other senses also, may suffer from such abnormal states. It is
noteworthy, but accords with what has been observed above as to
the relation between the sensation of resistance and the other
sensations, that, while hallucinations of sight and hearing do not
always lead to hallucinations of touch and resistance, these latter
do on the contrary, as a rule, introduce hallucinations of sight and
hearing.! ^rid since sensations of resistance afford the strongest
presumption of a reality, the hallucinations of resistance are the
most disturbing and destructive to the mental heallh.-
The question is just this, how to distinguish in individual
cases between mental health and mental disease. If the sensations
of all the senses accord, and if the victim to hallucination at once
and with great ingenuity answers all the objections which can be
raised against his imaginary world, how is it to be decided who is
right ?
Single sensuous percepts cannot decide the question. They
may every one, taken alone, rest upon illusions or hallucinations.
The only possible mode of decision is by looking to the con-
nection among the various sensuous percepts. The several points at
which sensation of resistance (to keep to this) makes its appear-
ance, are not isolated, but appear in reciprocal connection. The
1 Brierre de Boismont, Ves Hallucinations, 3rd ed., p. 507, seg.
• Cf. E. Kraepeliii, iiber Tru^mahrnehmungeni," 0\\ Illusive Perceptions"), Vierttl-
jahrsschr. J'iif iviss. Phi!., v., p. 365.
2o8 OUTLINES OF PSYCHOLOGY [v
individual has then the problem given, to arrange his ideas in
accordance with this connection. If he does not find the proper
arrangement, he will encounter resistance, and finally suffer practical
disappointment or pain. Supposing that the right arrangement of
the ideas, as things were, is found, but that it conflicts with new
experiences, then doubt arises as to the accuracy of the first
percepts. If doubt does not arise, and if the intercourse with the
external world is continued, a sure destruction follows. It is for
this reason that children and the insane are removed from the
struggle of life ; they are not in a position to correct their ideas by
experience.
The real is that which we apprehend as real,— which in spite of
all effort to the contrary we must ultimately leave as it is, —
which we cannot but recognize. This " can't help" is a negative
and subjective criterion, and there can be no question of any
other. To the dreamer his dream is reality ; on awaking he
discovers that the dream was only illusory reality, conditioned by a
more comprehensive reality and finding its explanation within this.
So far as we can go in dreams without encountering sharp con-
tradictions and contradictory experiences, to that extent we believe
in the reality of the dream. There arrives a point, however, when
the threads give way. Even the most systematic of dreams is but
a fragment as compared with the totality into which progressive
experience conducts us. In this way all of our ideas which have not
their root in reality are corrected ; sooner or later their limita-
tions will appear, and it will be discovered that there are more
things in heaven and earth than are dreamt of in our philosophy.
In this way the knowledge of each individual has its con-
summation in a complete image of the system of which he is a
link. The individual's own powers cannot, however, efi'ect much in
this respect. He cannot correct all his illusions if he depends on
himself alone. Equally little can this be done by the individual
nation and the individual age. The pictures of the universe
formed by the several individuals, nations, and ages, conflict in turn
among themselves, and in this conflict man's conception of the
universe is slowly evolved to greater clearness and certainty. The
psychology of the individual leads here partly to the psychology
of races, partly to the history of all the sciences.
This does not determine whether the end can be reached at all.
Before we touch upon the large problem to which this gives rise, we
must call attention to an important concept, to which the preced-
V] THE PSYCHOLOGY OF COGNITION 2og
ing inquiry has brought us, and of which this is the place to state
the psychological basis.
3. The evidence of reality is given, then, according to the results
we have just reached, in the firm connection of the percepts. We
can never therefore be so strongly convinced of single percepts, of
the reality of single things and occurrences, as of connected series
of things and occurrences. The more there is " method in our
madness," the more dangerous it is.
The firm bond by which things and events are brought into the
system of the real, we call the causal relation. We assume a
causal relation, wherever we discover that two phenomena are
linked together in such a way that the one unavoidably makes its
appearance when the other is given.
According to the popular conception of the causal relation, one
thing is the cause, another thing the effect. The difficulty which
might be found in things, supposed to exist independently, having
yet so much to do with one another as must be the case with
cause and effect, is from this standpoint easily overcome. A
creative or constraining power is attributed to the thing called
the " cause." The causes are personified, have ascribed to them
something analogous to the personal exertion of will.
David Hume was the first to make the popular conception of
causality a subject of thorough criticism. What do we really
mean — he asks— when we say, one thing is the cause of another .''
If it is replied that the cause produces the effect, then what
do we understand by "producing".? Can an explanation of this
be given which means anything but — causation ; so that we
again move in a circle ? — But if it is said that the causal relation is
only a necessary connection between two things, how is this
necessary connection to be proved ? Not by way of inference.