some sort. They lead to inconspicuous changes in brcatli-
ing, circulation, general muscular tension, and glandular or
otlier visceral activity, even if they do not lead to conspi-
cuous movements of the muscles of voluntary life. Not
only certain particular states of mind, then (such as those
called volitions, for exam2)le), but states of mind as such,
all states of mind, even luere thoughts and feelings, are
motor in their consequences. This will be made manifest
in detail as our study advances. Meanwhile let it be set
down jis one of the fundamental facts of the science with
M hich we are engaged.

It was said above that the 'eDiiditious' of states of cou-
seiousuess must be studied. The immediate condition of
a state of consciousness is an activity of some sort in the
cerebral hemispheres. This proposition is supported by so
many pathological facts, and laid by physiologists at the
ba.«e of so many of their reasonings, that to the medically
e<lucated mind it seems almost axiomatic. It would be
hard, however, to give any short and peremptory jiroof of
the unconditional dependence of mental action upon neural
ciuinge. That a general and usual amount of dependence
exists cannot possibly be ignored. One has only to con-
Bider how quickly consciousness may be (so far as we know)
abolished by a blow on the head, by rapid loss of blood, l)y
an epileptic discharge, by a full dose of alcohol, opium,
ether, or nitrous oxide — or how esisily it may be altered in
quality by a smaller dose of any of these agents or of others,
or by a fever, — to see how at the mercy of bodily happenings
our spirit is. A little stoj)page of the gall-duct, a swallow
of cathartic medicine, a (.-up of strong coflee at the i)roi)('r
moment, will entirely overturn fur the time a man's views
of life. Our moods and resolutiouB uro luoro determined



y



6 PSYCHOLOGY.

by the condition of our circulation than by our logical
grounds. Whether a man shall be a hero or a coward is
a matter of his temporary 'nerves.' In many kinds of
insanity, though by no means in all, distinct alterations of
the brain-tissue have been found. Destruction of certain
definite portions of the cerebral hemispheres involves losses
of memory and of acquired motor faculty of quite determi-
nate sorts, to which we shall revert again under the title of
aphasia,s. Taking all such facts together, the simple and
radical conception dawns upon the mind that mental action
may be uniformly and absolutely a function of brain-action,
varying as the latter varies, and being to the brain-action
as effect to cause.
/ This conception is the 'working hypothesis' which
underlies all the 'physiological psychology' of recent
years, and it will be the working hypothesis of this book.
Taken thus absolutely, it may possibly be too sweeping a
statement of what in reality is only a partial truth. But
the only way to make sure of its unsatisfactoriness is to
apply it seriously to every possible case that can turn up.
To work an hypothesis ' for all it is worth ' is the real, and
often the only, way to prove its insufficiency. I shall there-
fore assume without scruple at the outset that the uniform
correlation of brain-states with mind-states is a law of na-
ture. The interpretation of the law in detail will best show
where its facilities and where its difficulties lie. To some
readers such an assumption wdll seem like the most unjus-
tifiable a jiriori materialism. In one sense it doubtless is
materialism: it puts the Higher at the mercy of the Lower.
But although we affirm that the coming to 2^at^s of thought
is a consequence of mechanical laws, — for, according to
another 'working hypothesis,' that namely of physiology,
the laws of brain-action are at bottom mechanical laws, —
Ave do not in the least explain i\\e nature of thought by
affirming this dependence, and in that latter sense our
proposition is not materialism. ^ The authors who most
Unconditionally affirm the dependence of our thoughts



INTROD UCT0R7. 7

on our brain to be a fact are often the loudest to insist that
the fact is inexplicable, and that the intimate essence of
consciousness can never be rationally accounted for by any
material cause. It will doubtless take several generations
of psvchologists to test the hypothesis of dependence
with anything like minuteness. The books which postu-
late it will be to some extent on conjectural ground
lint tlie student will remember that the Sciences constantly
liave to take these risks, and habitually advance by zig-
zaofging from one absolute formula to another which cor-
rects it by going too far the otlier way. At present Psychol-
ogy is on the materialistic tack, and ought in the interests
of ultimate success to be allowed full headway even by
those who are certain she will never fetch the port without
putting down the helm once more. The only thing that is
l)crfectly certain is that when taken up into the total body
of Philosophy, the formulas of Psychology will appear with
a very different meaning from that whicii they suggest so
long as they are studied from the point of view of an
abstract and truncated 'natural science,' however practi-
cally necessary and indispensable their study from such a
provisional point of view may bo.

The Divisions of Psychology. — So far as possible, then,
we are to study states of consciousness in correlation with
their probable neural conditions. Now the nervous system
is well understood to-day to be nothing but a machine for
receiving impressions and discharging reactions preserva-
tive to the individual and his kind — so much of physiology
tlie reader will surely know. Anatomically, therefore, the
nervous system falls into three main divisions, comprising —

1) The fibres which carry currents in;

2) The organs of central redirection of them ; and
:;) The fibres which carry them out.

r uii(;ti(jiuilly, we have sensation, central reflection, and
motion, to correspond to these anatomical divisions. In
Psychology we may divide our work according to a similar



8 PSTCHOLOOT.

scheme, and treat successively of three fundamental con-
scious processes and their conditions. The first will be
Sensation; the second will be Cerebration or Intellection;
the third will be the Tendency to Action. Much vagueness
results from this division, but it has practical conveniences
for such a book as this, and they may be allowed to pre-
vail over whatever objections may be urged.



t



K yr4/



CHAPTER II.

SENSATION IN GENERAL.

Incoming nerve-currents are the only agents which nor-
mally affect the brain. The human iiervu-centres are sur-
rounded by many dense wrappings of wliich the effect is
to protect them from the direct action of the forces of tlie
outer world. The hair, the thick skin of the scalp, the
skull, and two membranes at least, one of them a tough
one, surround the brain; and tliis organ moreover, like tlie
spinal cord, is bathed by a serous fluid in which it floats
suspended. Under these circumstances the only things
tliat can happen to the brain arc:

1) The dullest and feeblest mechanical jars;

2) Changes in the quantity and quality of the blood-
supply; and

3) Currents running in through the so-called afferent or
centripetal nerves.

The mechanical jars are usually ineffective; the effects
of tlie blood-clianges are usually transient; the nerve-cur-
rents, on the contrary, produce consequences of the most
vital sort, both at the moment of their arrival, and later,
through the invisible jiaths of escape which they plough in
the Hubstanfe of the organ and which, as we believe, remain
aa more or less permanent features of its structure, modify-
ing its action throughout all future time.



10 PSYCHOLOGY.

Each afferent nerve comes from a determinate part of
the periphery and is played upon and excited to its inward
activity by a particular force of the outer world. Usually
it is insensible to other forces : thus the optic nerves are
not im^jressible by air-waves, nor those of the skin by light-
waves. The lingual nerve is not excited by aromatic ef-
fluvia, the auditory nerve is unaffected by heat. Each
selects from the vibrations of the outer world some one
rate to which it responds exclusively. The result is that
our sensations form a discontinuous series, broken by enor-
mous ga}DS. There is no reason to suppose that the order
of vibratiojis in the outer world is anything like as inter-
rupted as tlie order of our sensations. Between the quick-
est audible air-waves (40,000 vibrations a second at the
outside) and the slowest sensible heat-waves (which num-
ber probably billions). Nature must somewhere have real-
ized innumerable intermediary rates which we have no
nerves for perceiving. The process in the nerve-fibres
themselves is very likely the same, or much the same, in
all the different nerves. It is the so-called 'current'; but
the current is star-led by one order of outer vibrations in
the retina, and in tlie ear, for example, by another. This is
due to the different terminal organs with which the several
afferent nerves are armed. Just as Ave arm ourselves with
a spoon to pick up soup, and with a fork to pick up meat,
so our nerve-fibres arm themselves Avith one sort of end-
apparatus to pick up air-waves, with another to pick up
ether- waves. The terminal apparatus always consists of
modified epithelial cells Avith Avhich the fibre is continuous.
The fibre itself is not directly excitable by the outer agent
which im2)resses tlie terminal organ. The optic fibres are
unmoved by the direct rays of the sun; a cutaneous nerve-
trunk may be touched Avith ice without feeling cold.* The

*The subject may feel pnin, liovvever, in tliis experiment; and it
must be admitted that nerve-fibres of every description, terminal
orsrans as well, are to some degree excitable by mechanical violence
and by the electric current.



BENSATIOX TX GENERAL. 11

fibres are mere transmitters; the terminal organs are so
many imperfect telephones into which tlie material Avorld
speaks, and each of which takes up but a portion of what
it says; tlie brain-cells at the fibres' central end are as
manv others at whicli the mind listens to the far-off c;ill.

The 'Specific Energies' of the Various Parts of the
."Brain. — To a certain extent anatomists have traced definitely
tiic paths which the sensory nerve-fibres follow after their
entrance into the centres, as far as their termination i:)
tlie gray matter of the cerebral convolutions.* It will be
shown on a later page that the consciousness which accom-
panies the excitement of this gray matter varies from one
portion of it to another. It is consciousness of things seen,
when the occipital lobes, and of things heard, when the
u])per part of the temporal lobes, share in the excitement.
Eai'h region of the cerebral cortex responds to tlie stiimila-
tion which its alTerent fibres bring to it, in a manner with
which a peculiar quality of feeling seems invariably cor-
related. U'his is what has been called the law of 'specific
energies ' in the nervous system. Of course we are with-
out even a conjectural explanation of the ground of such
a law. Psychologists (as Lewes, Wundt, Rosenthal, Gold-
scheider, etc.) have debated, a good deal as to whether the
specific quality of the feeling depends solely on the place
stimulated in the cortex, or on the sori of current which the
nerve pours in. Doubtless the sort of outer force habitu-
ally impinging on the end-organ gradually modifies (he
end-organ, the sort of commotion received from the end-
organ modifies the fibre, and the sort of current a so-modi-
fied fibre pours into the cortical centre modifies the centre.
The modification of the centre in turn (though no man



♦Thus tlie optic ncrve-liltrcs aro traced to the occipital lohos, the
olfactory tracts go to the h)wer part of the tcniporal lobo (hippocainpal
convolmioii), the aiulitory juTve-filircs puss lirht to tin? ccrcliclliim,
and prolmldy from thcnco to tlio upper part of tlie temporal lobe.
Thew anatomical tcrm.s ustfd in this chajiter will he explained later
Tb« cortex Is the gray »urfttc<j of the convolutions.



12 rSTCHOLOQY.

can guess how or why) seems to modify the resultant con-
sciousness. But tliese adaptive modifications must be ex-
cessively slow; and as matters actually stand in any adult
individual, it is safe to say that, more than anything else,
the place excited in his cortex decides what kind of thing
he shall feel. Whether we press the retina, or prick, cut,
pinch, or galvanize the living optic nerve, the Subject always
feels flashes of light, since the ultimate result of our opera-
tions is to stimulate the cortex of his occipital region.
Our habitual ways of feeling outer things thus depend on
which convolutions happen to be connected with the par-
ticular end-organs which those things impress. We see the
sunshine and the fire, simply because the only peripheral
end-organ susceptible of taking up the ether-waves which
these objects radiate excites those particular fibres which
run to the centres of sight. If we could interchange the
inward connections, we should feel the world in altogether
I new ways. If, for instance, we could splice the outer
/extremity of our optic nerves to our ears, and that of our
/'auditory nerves to our eyes, we should hear the lightning
)and see the thunder, see the symphony and hear the con-
\ ductor's movements. Such hypotheses as these form a good
training for neophytes in the idealistic philosophy !

Sensation distinguished from Perception. — It is impossi-
ble rigorously to define a sensation ; and in the actual life
of consciousness sensations, popularly so called, and per-
ceptions merge into each other by insensible degrees. All
we can say is that ivhat we mean by sensations are first
things in the way of consciousness. They are the immedi-
ate results upon consciousness of nerve-currents as they
enter the brain, and before they have awakened any sug-
gestions or associations with past experience. But it is
obvious that such immediate sensations can only be realized
in the earliest days of life. They are all but impossible to
adults with memories and stores of associations acquired.
Prior to all impressions on sense-organs, the brain is
plunged in deep sleep and consciousness is practically non-



SSXSATlOy IN GENERAL. 13

existent. Even the first weeks after birth are passed in
ulniost unbroken sleep by human infants. It takes a
strong message from the sense-organs to break tliis shunber.
In ;i new-born brain tliis gives rise to an absolutely pure
sensation. But the experience leaves its 'unimaginable
touch ' on the matter of the convolutions, and the next ini-
pret-siuii which a sense-organ transmits produces a cerebral
reaction in which the awakened vestige of the hist impres-
sion plays its part. Another sort of feeling and a higher
grade of cognition are the consequence. ' Ideas ' about the
object mingle with the awareness of its mere sensible pres-
ence, we name it, class it, compare it, utter propositions
concerning it, and the complication of the possible con-
sciousness which an incoming current may arouse, goes on
increasing to the end of life. In general, this higher con-
Bciousness about things is called Perception, tlie mere
inarticulate feeling of their j)resence is Sensation, so far as
we have it at all. To some degree we seem able to lapse
into this inarticulate feeling at moments when our atten-
tion is entirely dispersed.

Sensations are cognitive. A sensation is thus an abstrac-
tion seldom realized by itself ; and the object which a sen-
sation knows is an abstract object which cannot exist alone.
'Sensible fjualifie.s' are the objects of sensation. The sen-
sations of the eye are aware of the colors of things, those of
the ear are acquainted with their sounds / those of the skin
feel their tangible heaviness, sharpness, ^varmtU or coldness,
etc., etc. From all the organs of the body currents may
come which reveal to us the quality of ^>rtt;?, and to a cer-
tain extent that ot pleasure.

Su(di qualities as stickiness, roughness, etc., are sup-
poHcd to be felt tlirough the coojjeration of muscular sen-
sations with those of the skin. The geometrical qualities
of things, oji the (jther hand, their sha/ies, bitjnesses, (tis-
tanrps, etc. (so far a.s we discriminate and identify them),
are by nujst psycludogists supposed to be impossible with-
out the evocation of memories from the past; and the



14 PSICBOLOOr.

cognition of these attributes is thus considered to exceed
the power of sensation pure and simple.

' Knowledge of Acquaintance ' and ' Knowledge about,'—
Sensation, thus considered, differs from perception only in
the extreme simplicity of its object or content. Its object,
being a simple quality, is sensibly liomogeneous ; and its
function is that of mere acquaintance with this homo-
geneous seeming fact. Perception's function, on the other
hand, is that of knowing something about the fact. But
we must know loliat fact we mean, all the while, and the
various loliats are what sensations give^,, [Our earliest
thoughts are almost exclusively sensationalj They give us
a set of ivhats, or thats, or its', of subjects of discourse in
other words, with their relations not yet brought out. The
first time we see light, in Condillac's phrase we «re it rather
than see it. But all our later optical knowledge is about
what this experience gives. And though we were struck
blind from that first moment, our scholarship in the sub-
ject would lack no essential feature so long as our memory
remained. In training-institutions for the blind they teach
the pupils as much about light as in ordinary schools.
Reflection, refraction, the spectrum, the ether-theory, etc.,
are all studied. But the best taught born-blind pupil of
such an establishment yet lacks a knowledge which the
least instructed seeing baby has. They can never show
him ?t'A«Hight is in its 'first intention'; and the loss of
that sensible knowledge no book-learning can replace. x\ll
this is so obvious that we usually find sensation 'postulated'
as an element of exjjerience, even by those philosophers
who are least inclined to make much of its importance, or
to pay respect to the knowledge which it brings.

Sensations distinguished from Images, — Botli sensation
and perception, for all their difference, are yet alike in that
their objects appear vivid, lively, and iwesent. Objects
merely thought of, recollected, or imagi7ied, on the contrary,
are relatively faint and devoid of this pungency, or tang,
this quality of real presence which the objects of sensation



SENSATION IN GENERAL. 16

possess. Now the cortical brain-processes to which sensa-
tions are attached are due to incoming currents from the
periphery of tlie body — an external object must excite the
eye, ear, etc., before the sensation comes. Those cortical
processes, on tlie otlior hand, to whicli mere ideas or images
arc attached are due in all probability to currents from
other convolutions. It would seem, then, that the currents
from the periphery normally awaken a kind of brain-
activity which the currents from other convoUitions are
inadequate to arouse. To tliis sort of activity — a pro-
founder degree of disintegration, perhaps — the quality of
vividness, presence, or reality in the object of the resultant
consciousness seems correlated.

The Exteriority of Objects of Sensation. — Every thing Of
quality felt is felt in outer space. It is impossible to con-
ceive a brightness or a color otherwise tluin as extended and
outside of the bod3\ Sounds also appear in space. Con-
tacts are against the l)ody's surface ; and pains always
occupy some organ. An opinion which has had much
currency in psychology is that sensible qualities are first
apprehended as in the mind itself, and then ' projected ' from
it, or ' extradited,' by a secondary intellectual or super-sensa-
tional mental act. There is no ground whatever for tliis
opinion. The only facts which even seem to nuike for it
can be much better explained in another way, as we shall see
later on. The very first sensation which an infant gets in
for him tbe outer universe. And tlie universe wbich he
comes to know in later life is nothing l)ut an amplitiea-
tion of that first simple germ which, by accretion on the
one hand and intussusception on the other, has grown
80 big ami complex and articulate that its first estate
is unrememberable. In his diitiib awakening to the con-
sciousness of .sonift/ii/i;/ t/icrc, a tnere ttiis as yet (or some-
thing for whicli even tiie term t/ii.s would perlnqis be
too discriminative, and the intellectual acknowledgment of
which would be better exjiressed by the bare interjection
*lo!'), the infant encounters un oijject in whii h (though it



16 P8TCH0L0OT.

be given iu a pure sensation) all the ' categories of the
understanding' are contained. Jf has externality, objec-
tivity, unity, substantiality, causality, in tlte full sense in
which any later object or system of objects has these things.
Here the young knower meets and greets his world ; and
the miracle of knowledge bursts forth, as Voltaire says, as
much in the infant's lowest sensation as in the highest
achievement of a Newton's brain.

The physiological condition of this first sensible experi-
ence is probably many nerve-currents coming in from
various peripheral organs at once ; but this multitude of
organic conditions does not prevent the consciousness from
being one consciousness. We shall see as we go on that
it can be one consciousness, even though it be due to
the cooperation of numerous organs and be a conscious-
ness of many things together. The Object which the
numerous inpouring currents of the baby bring to his
consciousness is one big blooming buzzing Confusion.
That Confusion is the baby's universe; and the universe of
all of us is still to a great extent such a Confusion, poten-
tially resolvable, and demanding to be resolved, but not
yet actually resolved, into parts. It appears from first to
last as a space-occupying thing. So far as it is unanalyzed
and unresolved we may be said to know it sensationally;
but as fast as parts are distinguished in it and we become
aware of their relations, our knowledge becomes perceptual
or even conceptual, and as such need not concern us in tlie
present chapter.

The Intensity of Sensations. — A light may be so weak as
not sensibly to dispel the darkness, a sound so low as not
to be heard, a contact so faint that we fail to notice it. In
other words, a certain finite amount of the outward stimu-
lus is required to produce any sensation of its presence at
all. This is called by Fechner the law of the threshold —
something must be stepped over before the object can gain
entrance to the mind. An impression just above the
threshold is called the minimum visibile, audibile, QiQ



SENSATJON ly GENERAL.



17



From this point onwards, as the impressing force increases,
the sensation increases also, though at a slower rate, until
at last an acme of the sensation is reached which no incretise
in the stimulus can make sensibly more great. Usually,
before the dcme,j)ain begins to mix witk the specific char-
acter of the sensation. This is definitely observable in
the cases of great pressure, intense heat, cold, light, and
sound; and in those of smell and taste less definitely so
only from the fact that we can less easily increase the force
of the stimuli here. On the other hand, all sensations,
however unpleasant when more intense, are rather agree-
able than otherwise in their very lowest degrees. A faintly
bitter taste, or putrid smell, may at least be interesting.

Weber's Law. — I said that the intensity of the sensation
increases by slower steps than those by which its exciting




cause increases. If there were no threshold, and if eveiy
erjual increment in the outer stimulus produced an equal
increment in the sensation's intensity, a sim])le straight liiu*
would represent graphically the 'curve' of the relation
between the two things. Let the horizontal line stand for
the scale of intensities of the objective stimulus, so that at
it has no intensity, at 1 intensity 1, and so forth. Let
the verticals dnj])ped frimi tht; slanting line stand fur the
sensations aroused. At there will be no sensation; at I
there will be a sensation represented by the length of the
vortical .*>'' — 1, at "Z *>'f' sensation will be represented !»}



18 ^ PSTCHOLOOT.

S* — 2, and so on. The line of S's will rise evenly be-