Thomas Reid.

The works of Thomas Reid, D.D.; now fully collected, with selections from his umpublished letters online

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we can understand the meaning of the proposition,
a circle is square; but, on the coir rary, they said it
is impossible that a circle can be square, and the pro.
position affirming ihisis necessarily false, bec.iuse we
eanoot, in consciousness, bring to a unity ofreprc.
sentafion the repugnant notions, circle and square —
that is, conceive- the notion of square circle, tieid's
mistake in this matter is so i alpable that it is not
more surprising that he should have committed it,
than that so many should not only have followed him
in the opinion, but even have lauded it as the refuta-
tion of an important error. To shew how com-
pletely Heid mistook the philosophers, it will be suf-
ficient to quote a pa*-sage from Wolfs vernacular
Logic, which I take from the Knglish translation,
(one, by the by, of the few tolerable versions we have
of German philosophical works,) published m 1770: —

" It is carefully to be observed, that we have not
always the notion of the thing present to us, or in
view, when we speak or think of it ; but are satisfied
when we imagine w sufficiently understand what we
speak, if we think we recollect that we have had, at
another time, the notion which is to be joined tothis
or the other word ;• and thus we represent to our-
selves, as at a distance, or obscurely, the thing
denoted by the term.

'* Hence, it usually happens that, when we combine
words together, to each of which, apart, a meaning
or notion answers, we imagine we understan I what
we .utter, though that which is denoted by such com-
bined words be impossi 1 le. and consequently can
have no meaning. For that w ich is impos-ib c is



[[essay :

that can be meant by simple apprehension
or conception, when applied to a proposi-
tion. The axiom, therefore, amounts to
this : — Every proposition, of which you un-
derstand the meaning distinctly, is possible.
I am persuaded that I understand as dis-
tinctly the meaning of this proposition, Any
two sides of a triangle are together equal
to the third, as of this — Any two sides of a
triangle are together greater than. /he third ;
yet .the first of these is impossible.

Perhaps it will be said, that, though you
understand the meaning of the impossible
proposition, you cannot suppose or conceive
it to be true.

Here we are to examine the meaning of
the phrases of supposing and conceiving u,
proposition to be true. I can certainly sup-
pose it to be true, because I can draw con-
sequences from it which I find to be impos-
sible, as well as the proposition itself.

If, by conceiving it to be true, be meant
giving some degree of assent to it, how-
ever small, this, I confess, I cannot do.
But will it be said that every proposition to
which I can give any degree of assent, is
possible ? This contradicts experience, and,
therefore, the maxim c mnot be trua in
this sense.

Sometimes, when we say that we cannot
conceive a thing to he true, we mean by that
expression, that we judge it to be impossible.
In this sense I cannot, indeed, conceive
it to be true, that two sides of a triangle
are equal to the third. I judge it to be
impossible. If, then, we understand, in
this sense, that maxim, that nothing we can
conceive is impossible, the meaning will
be, that nothing is impossible which we
judge to be possible. But does it not often
happen, that what one man judges to be
possible, another man judges to be impos-
sible ? The maxim, therefore, is not true
in this sense. [403]

I am not able to find any other meaning
of conceiving a proposition, or of conceiving
tt to be true, besides these I have men-
tioned. I know nothing that can be meant
by having the idea of a proposition, but

nothing at all, ar.d of nothing there can be no idea.
For instance, ivc have a notion of gold, as also of
iron. But it is impossible that iron can at the same
time legold, consequently, neither can we have any
notion of iron-gold ; and yet we understand what
people mean when they mention

" In the instance alleged, it certainly strikes every
one, at first, that the expre-sion is an empty
sound ; but yet there are a thousand instances in which
it does not so easily sinke. For example, when I
say a rectilineal two-lined figure, a figure contained
under two right lines, I am equally well understood
as when I say, a right-lined triangle, a figure con-
tained untkr three right lines. Audit should seem
we had a distinct notion of both figures. However,
as we shew in Geometry that two right lines can
never contain space, it is also impossible to form a
notion nl a rectilineal two.hncd figure; and conse-
quently that expression is an empty sound." — I'. 55.

either the understanding its meaning, or
the judging of its truth. I can understand
a proposition that is false or impossible, as
well as one that is true or possible ; and I
find that men have contradictory judgments
about what is possible or impossible, as well
as about other things. In what sense then
can it be said, that the having an idea of a
proposition gives certain evidence that it ia
possible ?

If it be said, that the idea of a proposition
is an image of it in the mind, 1 think indeed
there cannot be a, distinct image, either in
the mind or elsewhere, of that which is
impossible ; but what is meant by the imago
of a proposition I am not able to compre-
hend, and I shall be glad to be informed.

2. Every proposition that is necessarily
true stands opposed to a contradictory pro-
position that is impossible ; and he that
conceives one conceives both. Thusaman
who believes that two and three necessarily
make five, must believe it to be impossiblo
that two and three should not make five.
He conceives both propositions when he
believes one. Every proposition carries its
contradictory in its bosom, and both are
conceived at the same time. " It is con-
fessed," says Mr Hume, " that, in all cases
where we dissent from any person, we con- '
ceive both sides of the question ; but we
can believe only one." From this, it cer-
tainly follows, that, when we dissent from ■
any person about a necessary proposition, *
we conceive one that is imposible ; yet I )l
know no philosopher who has made so "
much use of the maxim, that whatever we f.
conceive is possible, as Mr Hume. A great a
part of his peculiar tenets is built upon it ; -e
and, if it is true, they must be true. But :
he did not perceive that, in the passage 111
now quoted, the truth of which is evident, n
he contradicts it himself. [404] ;;

3. Mathematicians have, in many cases, Ǥ'
proved some things to be possible, and >i
others to be impossible, which, without oi
demonstration, would not have been be- tg
lieved. Yet I have never found that any j B
mathematician has attempted to prove a tr
thing to be possible, because it can be con- *;
ceived ; or impossible, because it cannot be >.
conceived. * Why is not this maxim applied In,
to determine whether it is possible to square %
the circle ? a point about which very emi-ij,,,
nent mathematicians have differed. It isy
easy to conceive that, in the infinite series u'.,
ot numbers, and intermediate fractions, it,
some one number, integral or fractional**;
may bear the same ratio to another, as tha
side of a square bears to its diagonal -\ yet w

tim« A df ^l et 1^'-' m f " rt ' f0Unded °" "'"■ intuit
t.ons of space-that is, in common lanauace. on ouiV

conceptions of space and its relations.'!? h" 60 ' °" '

t We are able tn conceive nothing infinite- andwdlw*
.-avTOHw*-, but we cannot cancel,", ,. .„,'""? £\ r
tmaome, t he possibility in qucstion.-H. ' ™^

[403, 4.04.1S, <



however conceivable this maybe, it maybe
demonstrated to be impossible.

4. Mathematicians often require us to
conceive things that are impossible, in order
to prove them to be so. This is the case in
all their demonstrations ad absurdum.
Conceive, says Euclid, a right line drawn
from one point of the circumference of a
circle to another, to fall without the circle :*
1 conceive this— I reason from it, until I
come to a consequence that is manifestly
absurd ; and from thence conclude that the
thing which I conceived is impossible.

Having said so much to shew that our
power of conceiving a proposition is no
criterion of its possibility or impossibility, I
shall add a few observations on the extent
of our knowledge of this kind.

1. There are many propositions which,
by the faculties God has given us, we judge
to be necessary, as well as true. AH
mathematical propositions are of this kind,
and many others. The contradictories of
such propositions must be impossible. Our
knowledge, therefore, of what is impossible,
must, at least, be as extensive as our know-
ledge of necessary truth.

2. By our senses, by memory, by testi-
■niony, and by other means, we know many

things to be true which do not appear to be
necessary. But whatever is true is pos-
sible. Our knowledge, therefore, of what is
po-sible must, at least, extend as far as our
knowledge of truth. [405]

3. If a man pretends to determine the
possibility or impossibility of things beyond
these limits, let him bring proof. I do not
say that no such proof can be brought. It
has been brought in many cases, particu-
larly in mathematics. But I say that his
lieing able to conceive a thing, is no proof
that it is possible. + Mathematics afford
many instances of impossibilities in the
nature of things, which no man would have
believed if they had not been strictly de-
monstrated. Perhaps, if we were able to
reason demonstratively in other subjects, to
aa great extent as in mathematics, wo might
find many things to be impossible, which
we conclude without hesitation, to be pos-

It is possible, you say, that God might
have made an universe of sensible and ra-
tional creatures, into which neither natural
nor moral evil should ever enter. It may
be so, for what I know. But how do you
know that it is possible ? That you can
lijpnceive it, I grant; but this is no proof.

F* c.,.-i:,i j,,',., not ' equire us to conceive or imagine
L * F.U( -lid dots "°' |t £ The proposition to which
iny such imposs w ' y 8M01ld of the third Hook of
»id must relents im

JjieElements — H- ^t it h really possible, but that
I,*. Not, certainly. me _ t „ i„ T „| TC , n0 ro „.

It» probhwn 'S""^ n | aw ,f thought. This latter
fepSimy-o".- in .pusHon.-H.
fi05, 406]

I cannot admit, as an argument, or even as
a pressing difficulty, what is grounded on
the supposition that such a thing is possible,
when there is no goud evidence that it is
possible, and, for anything we know, it may.
in the nature of things, be impossible.



Every man is conscious of a succession
of thoughts which pass in his mind while he
is awake, even when they are not excited
by external objects. [40C]

The mind, on this account, may be com-
pared to liquor in the state of fermentation.
When it is not in this state, being once at
rest, it remains at rest, until it is moved by
some external impulse. But, in the state
of fermentation, it has some cause of motion
in itself, which, even when there is no im-
pulse from without, suffers it not to be at
rest a moment, but produces a constant
motion and ebullition, while it continues to

There is surely no similitude between
motion and thought ; but there is an analogy,
so obvious to all men, that the same words
are often applied to both ; and many modi-
fications of thought have no name but such
as is borrowed from the modifications of^
motion. Many thoughts are excited by the
senses. The causes or occasions of these
may be considered as external. But, when
sueh external causes do not operate upon
us, we continue to think from some internal
cause. From the constitution of the mind
itself there isaconstant ebullition of thought,
a constant intestine motion ; not only of
thoughts barely speculative, but of senti-
ments,passions, and affections, which attend

This continued succession of thought has,
by modern philosophers, been called the
imagination." I think it was formerly called
the fancy, or the phaiUm-y.f If the old
name be laid aside, it were to be wished
that it had got a name less ambiguous than
that of imagination, a name which had two
cr three meanings besides.

It is often called the train of ideas. This
may lead one to think that it is a train of
bare conceptions ; but this would surely l.e
a mistake. It is made up of many other
operations of mind, as well as of concep-
tions, or ideas.

* By some onlv, and that improperly. — H.

t '1 he I arm I'mciginalifi, with its modifications in
the vulgar languages, was employed both in ancient
and modem times to express what the Greeks -deno-
minated $<xv7ixirl<z. Phantasy, of which Thansy or
Fancy is a corruption, and now employed in a more
limited sense, was a common name for Imagnuliow
with theohl I-.nglish writers. — II.




Memory, judgment, reasoning, passions,
affections, and purposes — in a word, every
operation of the mind, excepting those of
sense — is exerted occasionally in this train
of thought, and has its share as an ingre-
dient : so that we must take the word idea
in a very extensive sense, if we make the
train of our thoughts to be only a train of
ideas. [407]

To pass from the name, and consider the
thing, we may observe, that the trains of
thought in the mind are of two kinds : they
are either such as flow spontaneously, like
water from a fountain, without any exer-
tion of a governing principle to arrange
them ; or they are regulated and directed
by an active effort of the mind, with some
view and intention.

Before we consider these in their order,
it is proper to premise that these two kinds,
however distinct in their nature, are for
the most part mixed, in persons awake and
come to years of understanding.

On the one hand, we are rarely so vacant
of all project and design, as to let our
thoughts take their own course, without
the least check or direction. Or if, at any
time, we should be in this state, some object
will present itself, which is too interesting
not to engage the attention and rouse the
active or contemplative powers that were
at rest.

On the other hand, when a man is giving
' the most intense application to any specula-
tion, or to any scheme of conduct, when he
wills to exclude every thought that is fo-
reign to his present purpose, such thoughts
will often impertinently intrude upon him,
in spite of his endeavours to the contrary,
and occupy, by a kind of violence, some
part of the time destined to another pur-
pose. One man may have the command
of his thoughts more than another man.
and the same man more at one time than
at another. But, I apprehend, in the best
trained mind, the thoughts will sometimes
be restive, sometimes capricious and self-
willed, when we wish to have them most
under command. [408]

It has been observed very justly, that
we must not ascribe to the mind the power
of calling up any thought at pleasure, be-
cause such a call or volition supposes that
thought to be already in the mind; for,
otherwise, how should it be the object of
volition ? As this must be granted on the
one hand, so it is no less certain, on the
other, that a man has a considerable power
in regulatingand disposing his own thoughts.
Of this every man is conscious, and I can
no more doubt of it than I can doubt whether
I think at all.

We seem to treat the thoughts that pre-
sent themselves to the fancy in crowds, as
» great man treats those that attend his

levee. They are all ambitious of his at-
tention : he goes round the circle, bestow,
ing a bow upon one, a smile upon another ;
asks a short question of a third ; while a
! fourth is honoured with a particular con-
ference ; and the greater part have no par-
ticular mark of attention, but go as they
came. It is true, he can give no mark of
his attention to those who were not there
but he has a sufficient number for making
a choice and distinction.

In like manner, a number of thoughts
present themselves to the fancy spontane-
ously ; but, if we pay no attention to them,
nor hold any conference with them, they
pass with the crowd, and are immediately
forgot, as if they had never appeared. But
those to which we think proper to pay at-
tention, may be stopped, examined, and
arranged, for any particular purpose we
have in view.

It may likewise be observed, that a train
of thought, which was at first composed by
application and judgment, when it has
been often repeated, and becomes familiar,
will present itself spontaneously. Thus,
when a man has composed an air in music,
so as to please his own ear, after he has
played or sung it often, the notes will
arrange themselves in just order, and it
requires no effort to regulate their succes-
sion. [409]

Thus we see that the fancy is made up I
of trains of thinking — some of which are '
spontaneous, others studied and regulated, j
and the greater part are mixed of both
kinds, and take their denomination from that
which is most prevalent ; and that a train
of thought which at first was studied and \
composed, may, by habit, present itself
spontaneously. Having premised these
things, let us return to those trains of
thought which are spontaneous, which must |
be first in the order of nature.

When the work of the day is over, and a
man lies down to relax his body and mind,
he cannot cease from thinking, though he
desires it. Something occurs to his fancy ;
that is followed by another thing ; and so his
thoughts are carried on from one object to
another, until sleep closes the scene.

In this operation* of the mind, it is not
one faculty only that is employed ; there are
many that join together in its production.
Sometimes the transactions of the day are
brought upon the stage, and acted over
again, as it were, upon this theatre of the
imagination. In this case, memory surely
acts the most considerable part, since the
scenes exhibited are notfictions, butrealities,
which we remember ; yet, in this case, the

* The word process might be here preferable.
Operation would denote that the mmd is active in
associating the train of thought H.

[407- 40»]



memory doeB not act alone, other powers are
employed, and attend upon their proper
objects. The transactions remembered will
be more or less interesting ; and we cannot
then review our own conduct, nor that of
others, without passing some judgment upon
it. This we approve, that we disapprove.
This elevates, that humbles and depresses
us. Persons that are not absolutely indif-
ferent to us, can hardly appear, even to the
imagination, without some friendly or un-
friendly emotion. We judge and reason
about things as well as persons in such
reveries. We remember what a man said
and did ; from this we pass to his designs
and to his general character, and frame
.some hypothesis to make the whole con-
sistent. Such trains of thought we may
call historical. [410]

There are others which we may call ro-
mantic, in which the plot is formed by the
creative power of fancy, without any regard
to what did or will happen. In these also,
the powers of judgment, taste, moral senti-
ment, as well as the passions and affections,
come in and take a share in the execu-

In these scenes, the man himself com-
monly acts a very distinguished part, and
seldom does anything which he cannot ap-
prove. Here the miser will be generous,
the coward brave, and the knave honest.
Mr Addison, in the '• Spectator," calls this
play of the fancy, castle-building.

The young politician, who has turned his
thoughts to the affairs of government, be-
comes, in his imagination, a minister of
state. He examines every spring and wheel
of the machine of government with the
nicest eye and the most exact judgment.
He finds a proper remedy for every disorder
of the commonwealth, quickens trade and
manufactures by salutary laws, encourages
arts and sciences, and makes the nation
happy at home and respected abroad. He
feels the reward of his good administration,
in that self-approbation which attends it,
and is happy in acquiring, by his wise and
patriotic conduct, the blessings of the present
age, and the praises of those that are to

It is probable that, upon the stage of
imagination, more great exploits have been
performed in every age than have been
upon the stage of life from the beginning of
the world. An innate desire of self-appro-
bation is undoubtedly a part of the human
constitution. It is a powerful spur to
worthy conduct, and is intended as such by
the Author of our being. A man cannot
be easy or happy, unless this desire be in
some measure gratified. While he con-
ceives himself worthless and base, he can
relish no enjoyment. The humiliating,
mortifying sentiment must be removed, and

this natural desire of self-approbation will
either produce a noble effort to acquire real
worth, which is its proper direction, or it
will lead into some of those arts of self-
deceit, which create a false opinion of
worth. [411]

A castle-builder, in the fictitious scenes
of his fancy, will figure, not according to his
real character, but according to the highest
opinion he has been able to form of himself,
and perhaps far beyond that opinion. For,
in those imaginary conflicts, the passions
easily yield to reason, and a man exerts the
noblest efforts of virtue and magnanimity;
with the same ease as, in his dreams, he
flies through the air or plunges to the bot-
tom of the ocean.

The romantic scenes of fancy are most
commonly the occupation of young minds,
not j et so deeply engaged in life as to have
their thoughts taken up by its real carts
and business.

Those active powers of the mind, whi.h
are most luxuriant by constitution, or have
been most cherished by education, im-
patient to exert themselves, hurry the
thought into scenes that give them play ;
and the boy commences in imagination,
according to the bent of his mind, a general
or a statesman, a poet or an orator.

When the fair ones become castle-build-
ers, they use different materials ; and, while
the young soldier is carried into the held of
Mars, where he pierces the thickest squad-
rons of the enemy, despising death in all
its forms, the gay and lovely nymph, whose
heart has never felt the tender passion, is
transported into a brilliant assembly, where
she draws the attention of every eye, and
makes an impression on the noblest heart.

But no sooner has Cupid's arrow found
its way into her own heart, than the whole
scenery of her imagination is changed.
Balls and assemblies have now no charms.
Woods and groves, the flowery bank and
the crystal fountain, are the scenes she
frequents in imagination. She becomes an
Arcadian shepherdess, feeding her flock
beside that of her Strephon, and wants nc
more to complete her happiness. [412]

In a few years the love-'.ick maid is
transformed into the solicitous mother. Hei
smiling offspring play around her. Sha
views them with a parent's eye. Her ima-
gination immediately raises them to man-
hood, and brings them forth upon the staga
of life. One son makes a figure in the
army, another shines at the bar ; he<
daughters are happily disposed of in mar-
riage, and bring new alliances to the family.
Her children's children rise up before her ;
and venerate her grey hairs.

Thus the spontaneous sallies of fancy am
as various as the cares and fears, the de.
sires and hopes, of man.





Quicquid ajumt homines, voturo, timor, Ira, voluptas,
tiaudia, discursus :

These fill up the scenes of fancy, as well
a<? the page of the satirist. Whatever
possesses the heart makes occasional ex-
cursions into the imagination, and acts such
scenes upon that theatre as are agreeable
to the prevailing passion. The man of
traffic, who has committed a rich cargo to
the inconstant ocean, follows it in his
thought, and, according as his hopes or his
fears prevail, he is haunted with storms,
and rocks, and shipwreck ; or he makes a
happy and a lucrative voyage, and, before
his vessel has lost sight of land, he has dis-
posed of the profit which she is to bring at
her return.

The poet is carried into the Elysian fields,

Online LibraryThomas ReidThe works of Thomas Reid, D.D.; now fully collected, with selections from his umpublished letters → online text (page 86 of 114)