allax whicli follows on slightly moving tlie head. "When
awakened, however, it seems optical, and not heteroge-
neous with the other two dimensions of the visual field.

The mutual equivalencies of tlie distance-dimension with
the up-and-down and right-to-left dimensions of the field
of view can easily be settled without resorting to cxixtI-
ences of touch. A being reduced to a single eyeball
would perceive the same tridimensional world which 7,q
do, if he had our intellectual powers. For the mmc moving
things, by alternately covering different parts of his retina,
would determine the mutual equivalencies of the first two
dimensions of the field of view; and by exciting the physi-
ological cause of his [jerccjttion of depth in various degrees,
they would esfablish u scale of equivalency between the
first iM'o uud the third.



548 PSYGHOLOGT.

Pirst of all, one of the sensations given by the object
KovXdi be chosen to represent its * real ' size and shape, in
accordance with the principles so lately laid down. One
igensation would measure the 'thing' present, and the
* thing' would measure the other sensations — the periph-
eral parts of the retina would be equated with the cen-
tral by receiving the image of the same object. This
needs no elucidation in case the object does not change its
distance or its front. But suppose, to take a more compli-
cated case, that the object is a stick, seen first in its whole
length, and then rotated round one of its ends; let this
fixed end be the one near the eye. In this movement the
stick's image will grow progressively shorter; its farther
end will appear less and less separated laterally from its
fixed near end ; soon it will be screened by the latter, and
then reappear on the opposite side, the image there finally
resuming its original length. Suppose this movement to
become a familiar experience; the mind will presumably
react upon it after its usual fashion (which is that of
unifying all data which it is in any way possible to unify),
and consider it the movement of a constant object rather
than the transformation of a fluctuating one. Now, the
sensation of depth which it receives during the experience
is awakened more by the far than by the near end of the
object. But how much depth ? What shall measure its
amount ? Why, at the moment the far end is about to be
eclipsed, the difference of its distance from the near end's
distance must be judged equal to the stick's whole length;
but that length has already been seen and measured by a
certain visual sensation of breadth. So toe find that giveti
amounts of the visual depthfceling become signs of given
amounts of the visual hreadtli-feeUng, depth becoming equated
with breadth. The measurement of distajice is, as Berkeley
truly said, a result of suggestion and experience. But
visual experience alone is adequate to produce it, and this he
erroneously denied.



TSE PERCEPTION OF SPACE. 349

The Part played "by the Intellect in Space-perception. —
But although Berkclo}- was wrong in his assertion that out
of optical experience alone no perception of distance can
be evolved, lie gave a great impetus to psycliology by
showing liow originally incoherent and incommensurable
in respect of their extensiveness our different sensations
are, and how our. actually so rapid space-perceptions are
almost altogether acquired by education. Touch-space is
one world; sight-space is another world. The two worlds
have no essential or intrinsic congruence, and only through
the * association of ideas* do we know what a seen object
signifies in terms of touch. Persons with congenital cata-
racts relieved by surgical aid, whose world until the opera-
tion has been a world of tangibles exclusively, are ludi-
crously unable at first to name any of the objects which
newly fall upon their eye. "It might very well be a
horse" said the latest patient of this sort of whom we have
an account, when a lU-litre bottle was held up a foot from
his face.* Neither do such patients have aiiy accurate
notion in motor terms of the relative distances of things
from their eyes. All such confusions very quickly dis-
appear with practice, and the novel optical sensations
translate themselves into the familiar language of touch.
The facts do not prove in the least that the optical sensa-
tions are not apatial, but only that it needs a subtler sense
for analogy than most people have, to discern the name
ppatial aspects and relations in them which previously-
kti()W!i tactile and motor experiences have yielded.

Conclusion. — To sum up, the whole history of space-per-
ception is explicable if we Jidmit on the one hand sensa-
tions with certain amounts of extensity native to them,
and on the other the ordinary powers of discrimination,
pelcr-tion, and association in tho mind's dealings with
tiiem. The fiuctuating im])orL ui" many of our optical

•Cf. Haftilmann in ZfitscUrift fllr I'sycbol. und riiysiol. der Sin-
aesor^ane, li. 78.



350 PSTCH0L0O7.

sensations, the same sensation being so ambiguous as re-
gards size, shape, locality, and the like, has led many to
believe that such attributes as these could not possibly be
the result of sensation at all, but must come from some
higher power of intuition, synthesis, or whatever it might
be called. But the fact that a present sensation can at any
time become the sign of a represented one judged to be more
real, sufficiently accounts for all the phenomena without
the need of supposing that the quality of extensity is
created out of non-extensive experiences by a super-sensa-
tional faculty of the mind.



CHAPTER XXII.

REASONING.

What Reasoning is. — We talk of man being the rational
animal; and the traditional intellectuaiist philosophy has
always made a great point of treating the brutes as wholly
irrational creatures. Nevertheless, it is by no means easy
to decide just what is meant by reason, or how the pe-
culiar thinking process called reasoning differs from other
thouglit-sequences which may lead to similar results.

Much of our thinking consists of trains of images sug-
gested one by another, of a sort of spontaneous revery of
which it seems likely enough that the higher brutes should
be capable. This sort of thinking leads nevertheless to
rational conclusions, both practical and theoretical. The
links between 'the terms are either ' contiguity ' or 'similar-
ity/ and with a mixture of both these things we can hardly
be very incoherent. As a rule, in this sort of irresponsible
thinking, the terms which fall to be coujded together are
empirical concretes, not abstractions. A sunset may call
up the vessel's deck from which I saw one last summer,
the companions of my voyage, my arrival into port, etc.;
or it may make me think of solar myths, of Hercules' and
Hector's funeral pyres, of Homer and whether he could
write, of the (ireek alphabet, etc. If habitual contiguities
j)rcd()miiiato, we have a ])rosaic mind; if rare contiguities,
or siniiiarities, liavo free i)lay, we call the person fanciful,
j)Octic, or witty. Hut the tliought as a rule is of matters
taken in their entirety. Having been thinking of one, we
find later that wft are tliinking of another, to which we have
been lifted along, we liardly know how. If au abstract



352 P8TCH0L007.

quality figures in the procession, it arrests our attention
buc for a moment, and fades into something else; and is
never very abstract. Thus, in thinking of the sun-myths,
we may have a gleam of admiration at the gracefulness of
the primitive human mind, or a moment of disgust at the
narrowness of modern interpreters. But, in the main, we
think less of qualities than of concrete things, real or pos-
sible, just as we may experience them.

Our thought here may be rational, but it is not reasoned,
is not reasoning in the strict sense of tlie term. In reason.-
ing, although our results may be thought of as concrete
things, they are not suggested immediately hy other cojicrete
tilings, as in the trains of simply associative thought.
They are linked to the concretes which precede them by
intermediate steps, and these steps are formed by abstract
general characters articulately denoted and expressly ana-
lyzed out. A thing inferred by reasoning need neither
have been an habitual associate of the datum from which
we infer it, nor need it be similar to it. It may be a thing
entirely unknown to our previous experience, something
which no simple association of concretes could ever have
evoked. The great difference, in fact, between that sim-
pler kind of rational thinking which consists in the con-
crete objects of past experience merely suggesting each
other, and reasoning distinctively so called, is this: that
whilst the empirical thinking is only reproductive, reason-
ing is productive. An empirical, or ' rule-of-thnmb,'
thinker can deduce nothing from data with whose beha-
vior and associates in the concrete he is unfamiliar. But
put a reasoner amongst a set of concrete objects which he
has neither seen nor heard of before, and with a little time,
if he is a good reasoner, he will make such inferences from
them as will quite atone for his ignorance. Reasoning
helps us out of unprecedented situations — situations for
which all our common associative wisdom, all the ' educa-
tion ' which we share in common with the beasts, leaves us
without resource.



REASONING. 353

Exact Definition of it. — Let us make this ahiUty to deal
with /Kitrl data t/ie technical differentia of reasoning.
This will sufticieiitly mark it out from common associative
thinking, and will immediately enable us to say just what
peculiarity it contains.

It contai)is analysis and abstraction. Whereas the
merely empirical thinker stares at a fact in its entirety,
and remains helpless, or gets ' stuck,' if it suggests no con-
comitant or similar, the reasoner breaks it up and notices
some one of its separate attributes. This attribute he
takes to be the essential part of the whole fact before him.
This attribute has properties or consequences which the
fact until then was not known to have, but which, now
that it is noticed to contain the attribute, it must have.

Call the fact or concrete datum S;
the essential attribute M;
the attribute's property P.

Then the reasoned inference of P from S cannot be made
without M's intermediation. The * essence ' M is thus that
third or middle term in the reasoning which a moment ago
was pronounced essential. Fur his original concrete S the
reasoner substitutes its abstract property M. What is true
of M, what is coupled with M, thereupon holds true of S,
is coupled with S. As M is properly one of the jmrts of
the entire S, reasoning may then be very well defined as
the substitution of parts and their implications or conse-
quences for wholes. And the art of the reasoner will con-
sist of two stages:

First, sagacity, or the ability to discover what part, M,
lies embedded in the whole S which is before him;

Second, learning, or the ability to recall promptly M's
conHcquoiices, concomitants, or implications.

If we glance at tlie ordinary syllogism —

M is P;
S is M ;

. • . S is P



354 rSTCHOLOOY.

^we see that the second or minor premise, the 'subsump-
tion ' as it is sometimes called, is the one requiring the
sagacity; the first or major the one requiring the fertility,
or fulness of learning. Usually the learning is more apt to
be ready than the sagacity, the ability to seize fresh aspects
in concrete things being rarer than the ability to learn old
rules ; so that, in most actual cases of reasoning, the minor
premise, or the way of conceiving the subject, is the one
that makes the novel step in thought. This is, to be sure,
not always the case; for the fact that M carries P with it
may also be unfamiliar and now formulated for the first
time.

The perception that S is M is a mode of conceiving S.
The statement that M is P is an abstract or general 2)ropo-
sition. A word about both is necessary.

What is meant by a Mode of Conceiving. — When we con-
ceive of S merely as M (of vermilion merely as a mercary-
compound, for example), we neglect all the other attri-
butes which it may have, and attend exclusively to this
one. We mutilate the fulness of S's reality. Every reality
has an infinity of aspects or properties. Even so simple a
fact as a line which you trace in the air may be considered
in respect to its form, its length, its direction, and its loca-
tion. When we reach more complex facts, the number of
ways in which Ave may regard them is literally endless.
Vermilion is not only a mercury-compound, it is vividly
red, heavy, and expensive, it comes from China, and so on,
ad infinitum. All objects are well-springs of properties,
which are only little by little developed to our knowledge,
and it is truly said that to know one thing thoroughly
would be to know the whole universe. Mediately or im-
mediately, that one thing is related to everything else; and
to know all about it, all its relations need be known. But
each relation forms one of its attributes, one angle by
which some one may conceive it, and while so conceiving
it may ignore the rest of it. A man is such a complex
fact. But out of the complexity all that an army com*



jiUJAsoyjJvo. 355

uiissary picks out as important for his purposes is his prop-
erty of eating so many pounds a day; the general, of
marching so many miles; the chair-maker, of having such
a shape; the orator, of respundiiig to such and such feel-
ings; the theatre-numagfr, of being ^villing to pay just
such a price, and no more, for an evening's amusement.
Each of these persons singles out the particular side of the
entire num whicli has a bearing on his concerns, and not
till this side is distinctly and separately conceived can the
proper practical conclusions /or fJinf reasoner be drawn;
and when they are drawn the man's other attributes may
be ignored.

All ways of conceiving a concrete fact, if they are true
ways at all, are equally true ways. There is no property
ABSOLUTELY essential to any one thing. The same prop-
erty which figures as the essence of a thing on one occasion
becomes a very inessential feature upon another. Now
that I am writing, it is essential that I conceive my paper
as a surface for inscription. If I failed to do that, T
shoull have to stop my work. But if I wished to light a
fire, and no other materials were by, the essential way of
conceiving the paper Avould be as combustible material;
and I need then have no thought of any of its other des-
tinations. It is really all that it is: a combustible, a writ-
ing surface, a thin thing, a hydrocarbonaceous thing, a
thing eight inches one way and ten another, a thing just
one furlong east of a certain stone in my neighbor's field,
an American thing, etc., etc., ad infinitum. "Whichever
one of these Juspects of its being I tenii)orarily class it
under makes me unjust to the other aspects. T.ut as I
always am classing it under one aspect or another, I am
always unjust, always partial, always exclusive. My ex-
cuse is necessity — the necessity which my finite and prac-
tical nature lays uju)!! nu'. My thinking is first and last
and always U)V the sake of my doing, and I can only do one
thing at a time. A Cod who is su])j)OKed to drive the
whole universe abreast may also be suj)posed, witliout



356 PS7CH0L0GT.

detriment to his activity, to see all parts of it at once and
without emphasis. But were our human attention so to
disperse itself, we should simjily stare vacantly at things at
large aud forfeit our opportunity of doing any particular
act. Mr. Warner, in his Adirondack story, shot a bear by
aiming, not at his eye or heart, but 'at him generally.'
But we cannot aim 'generally' at the universe; or if we
do, we miss our game. Our scope is narrow, and we must
attack things piecemeal, ignoring the solid fulness in which
the elements of Nature exist, and stringing one after an-
other of them together in a serial way, to suit our little
interests as they change from hour to hour. In this, the
partiality of one moment is partly atoned for by the differ-
ent sort of partiality of the next. To me now, writing
these words, emphasis and selection seem to be the essence
of the human mind. In other chapters other qualities
have seemed, and will again seem, more important parts of
psychology.

Men are so ingrainedly partial that, for common-sense
and scholasticism (which is only common-sense grown ar-
ticulate), the notion that there is no one quality genuinely,
absolutely, and exclusively essential to anything is almost
unthinkable. "A thing's essence makes it luhat it is.
Without an exclusive essence it would be nothing in par-
ticular, would be quite nameless, we could not say it was
this rather than that. What you write on, for example, —
why talk of its being combustible, rectangular, and the
like, when you know that these are mere accidents, and
that what it really is, and was made to be, is just paper
and nothing else?" The reader is pretty sure to make
some such comment as this. But he is himself merely
insisting on an aspect of the thing which suits his own
petty purpose, that of naming the thing; or else on an
aspect which suits the manufacturer's purpose, that of
-producing an article for ivliicli there is a vulgar demand.
Meanwhile the reality overflows these purposes at every
pore. Our usual purpose with it, our commonest title for



iih'Ai>OXJNG. S/lT

it, and the properties wliicli this title suggests, liave in
reality nothing sacramental. Tiiey characterize vs more
than they characterize the thing. But we are so stuck in
our prejudices, so petrified intellectually, that to our vul-
garest names, with their suggestions, we ascribe an eternal
and exclusive worth. The thing must be, essentially,
what the vulgarest name connotes; what less usual names
connote, it can be only in an 'accidental' and relatively
unreal sense.*

Locke undermined the fallacy. But none of his suc-
cessors, so far as I know, have radically escaped it, or seen
that the only meaning of essence is teleological, and that
classification and conception are purely teleological 2ceap-
ons of the mind. The essence of a thing is that one of its
properties which is so important for 1111/ interests that in
comparison with it I may neglect the rest. Amongst those
other things which have this important property I class it,
after this property I name it, as a thing endowed with this
property I conceive it; and whilst so classing, naming, and
conceiving it, all other truth about it becomes to me as
naught. The properties which are important vary from
man to man and from hour to hour. Hence divers appel-
lations and conceptions for the same thing. But nu'ny
objects of daily use — as paper ink, butter, over'^oat — have
properties of such constant unwavering importance, and
have ruch stereotyped names, that we end by believing that
to conceive them in those ways is to conceive them in '.he
only true way. Those are no truer ways of conceiving



• Keatlfrs brought up on Popular Scienr«^ imiy tliink that the mo-
lecular structure of things is their real essence in an alisolute sense,
and that water is IMJ-H more deej)]}- and truly than it is a solveni,
of sugar or a slaker of thirst. Not a whit I It is a/l of these things
with e(jual reality, and the only reason why fur tlie clumuit it is
H-f)-H primarily, and only wcondarily the? other things, is that
for /li-K jiurpoHf of laixiratiiry nhaiysis and synthesis, and inclusion in
the Bcience vhich treats of coiniH)sitionH and decom|M>sitions, the
H-O-H asjK'ct of it Ih the more inn>ortant one to bear in mind



858 PSTCHOLOGY.

them than any others; they are only more frequently ser-
viceable ways to us.

Reasoning is always for a subjective interest. To re-
vert now to our symbolic representation of the reasoning
process:

M isP
S is M



S isP

M is discerned and picked out for the time being to be
the essence of the concrete fact, phenomenon, or reality, S.
But M in this world of ours is inevitably conjoined with
P; so that P is the next thing that we may expect to find
conjoined with the fact S. We may conclude or infer P,
through the intermediation of the M which our sagacity
began by discerning, when S came before it, to be the es-
sence of the case.

Now note that if P have any value or importance for us,
M was a very good character for our sagacity to pounce
upon and abstract. If, on the contrary, P were of no im-
portance, some other character than M would have been a
better essence for us to conceive of S by. Psychologically,
as a rule, P overshadows the process from the start. We
are seeking P, or something like P. But the bare totality
of S does not yield it to our gaze; and casting about for
eome point in S to take hold of which will lead us to P,
we hit, if we are sagacious, upon M, because M happens to
be just the character which is knit up with P. Had we
wished Q instead of P, and were N a property of S conjoined
with Q, we ought to have ignored M, noticed N, and con-
3eived of S as a sort of N exclusively.

Reasoning is always to attain some particular conclusion,
or to gratify some special curiosity. It not only breaks
up the datum placed before it and conceives it abstractly,
it must conceive it rigidly too; and conceiving it rightly
means conceiving it by that one particular abstract charac-
ter which leads to the one sort of conclusion which it in
the reasoner's temporary interest to attain.



REASOKmO. 359

The resulf.<f of reasoning may be hit npon by accident.
The stereoscope was actually a result of reasoning; it is
conceivable, however, tliat a man playing with pictures and
mirrors might accidentally have hit upon it. Cats have
been known to open doors by pulling latches, etc. But no
cat. if the latch got out of order, could open the door again,
unless some new accident of random fumbling taught her
to associate some new total movement with the total phe-
nomenon of the closed door. A reasoning man, however
would open the door by first analyzing the hindrance. lie
would ascertain what particular feature of the door was
wrong. The lever, e.g., does not raise the latch sufliciently
from its slot — case of insufficient elevation: raise door
bodily on hinges ! Or door sticks at bottom by friction
against sill : raise it bodily up ! Kow it is obvious that a
child or an idiot might without this reasoning learn the
rule for opening that particular door. I remember a clock
which the maid-servant had discovered would not go unless
it were supported so as to tilt slightly forwards. She had
stumbled on this method after many weeks of groping,
Tlie reason of the stoppage was the friction of the pendu-
lum-bob against the back of the clock-case, a reason which
an educated man would have analyzed out in five minutes.
I have a student's lamp of which the flame vibrates most
unpleasantly unless the chimney be raised about a sixteenth
of an inch. I learned the remedy after much torment by
accident, and now always keep the chimney up with a small
wedge. But my procedure is a mere association of two
totals, disejised object and remedy. One learned in pneu-
matics could have abstracted the cause of the disease, and
thence inferred the remedy immediately. By many mejis-
urenu-nts of triangles one might find their area always
efjual to their height multiplied by half their base, and one
might formuhiTo an emj)irieal law to that etTeet. liut a
reasoner saves himself all this trouble by seeing that it is
the essence {pro hue vice) of a triangle to be the half of a
parallelogram whose area is the height into the entire base.



360 P8TCH0L0OY.

To see this lie must invent additional lines ; and the geom-
eter must often draw such to get at the essential property
he may require in a figure. The essence consists in some
relation of the figure to the new lines, a relation not obvious
at all until they are put in. The geometer's genius lies in
the imagining of the new lines, and his sagacity in the per-
ceiving of the relation.

Thus, there are two great points in reasoning. First
an extracted character is taken as equivalent to the entire
datum from which it comes; and,

Second, the character thus taken suggests a certain conse
quence more obviously than it tvas suggested by the total
datum as it originally came. Take these points again,
successively.

1) Suppose I say, when offered a piece of cloth, " I won't
buy that; it looks as if it would fade," meaning merely
that something about it suggests the idea of fading to my