Thomas Reid.

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

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touch ; but I perceive them by means of a
sensation which indicates them. This sens-
ation not being painful, I commonly give no
attention to it. [ 229 ] It carries my thought
immediately to the thing signified by it, and
is itself forgot, as if it had never been. But,
by repeating it, and turning my attention
to it, and abstracting my thought from the
thing signified by it, I find it to be merely
a sensation, and that it has no similitude to
the hardness, smoothness, or coldness of
the table, which are signified by it.

It is indeed difficult, at first, to disjoin
things in our attention which have always
been conjoined, and to make that an object
of reflection which never was so before ;
but some pains and practice will overcome
this difficulty in those who have got the
habit of reflecting on the operations of their
own minds.

Although the present subject leads us
only to consider the sensations which we
have by means of our external senses, yet
it will serve to illustrate what has been said,
aDd, I apprehend, is of importance in itself,
to observe, tnat many operations of mind,
to which we give, one name, and which we
always consider as one thing, are complex
in their nature, and made up of several
more simple ingredients ; and of these ingre-
dients sensation very often makes one. Of
this we shall give some instances-

The appetite of hunger includes an un-
easy sensation, and a desire of food. Sens-
ation and desire are different acts of mind.
The last, from its nature, must have an
object ; the first has no object These two
ingredients may always be separated in
thought — perhaps they sometimes are, in
reality ; but hunger includes both.

Benevolence towards our fellow-creatures
includes an agreeable feeling ; but it includes
also a desire of the happiness of others.
The ancients commonly called it desire.
Many modernschuse rather to call it a feel-
ing. Both are right : and they only err who
jixclude either of the ingredients. [230]

Whether these two ingredients are neces-
sarily connected, is, perhaps, difficult for us
to determine, there being many necessary
connections which we do not perceive to be
necessary ; but we can disjoin them in
thought. They are different acts of the

An uneasy feeling, and a desire, are, in
like manner, the ingredients of malevolent
affections ; such as malice, envy, revenge.
The passion of fear includes an uneasy
sensation or feeling, and an opinion of
danger ; and hope is made up of the con-
trary ingredients. When we hear of a
heroic action, the sentiment which it raises
in our mind, is made up of various ingre-
dients. There is in it an agreeable feeling,
a benevolent affection to the person, and a
judgment or opinion of his merit.

If we thus analyse the various operations
of our minds, we shall find that many of
them which we consider as perfectly simple,
because we have been accustomed to call
them by one name, are compounded of more
simple ingredients ; and that sensation, or
feeling, which is only a more refined kind
o f sensation, makes one ingredient, not
only in the perception of external objects,
but in most operations of the mind.

A small degree of reflection may satisfy
us that the number and variety of our sens-
ations and feelings is prodigious ; for, to
omit all those which accompany our appe-
tites, passions, and affections, our moral
sentiments and sentiments of taste, even
our external senses, furnish a great variety
of sensations, differing in kind, and almost
in every kind an endless variety of degrees.
Every variety we discern, with regard to
taste, smell, sound, colour, heat, and cold,
and in the tangible qualities of bodies, is
indicated by a sensation corresponding to

The most general and the most import-
ant division of our sensations and feelings,
is into the agreeable, the disagreeable, and
the indifferent. Everything we call plea-
sure, happiness, or enjoyment, on the one
hand ; and, on the other, everything we
call misery, pain, or uneasiness, is sensa-
tion or feeling ; for no man can for the pre-
sent be more happy or more miserable than
he feels himself to be. [231] He cannot
be deceived with regard to the enjoyment
or suffering of the present moment.

But I apprehend that, besides the sens-
ations that are either agreeable or disagree-
able, there is still a greater number that
are indifferent. * To these we give so little
attention, that they have no name, and are
immediately forgot, as if tney had never
been ; and it requires attention to the ope-

* This is a point in dispute amnitg philosophers




rations of our minds to be convinced of their

For this end we may observe, that, to a,
good ear, every human voice is distinguish-
able from all others. Some voices are plea-
sant, some disagreeable ; but the far greater
part can neither be said to be one nor the
other. The same thing may be said of
other sounds, and no less of tastes, smells,
and colours ; and, if we consider that our
senses are in continual exercise while we are
awake, that some sensation attends every
object they present to us, and that familiar
objects seldom raise any emotion, pleasant
or painful, we shall see reason, besides the
agreeable and disagreeable, to admit a third
class of sensations that may be called in-

The sensations that are indifferent, are
far from being useless. They serve as
signs to distinguish things that differ ; and
the information we have concerning things
external, comes by their means. Thus, if
a man had no ear to receive pleasure from
the harmony or melody of sounds, he would
still find the sense of hearing of great
utility. Though sounds give him neithei
pleasure nor pain of themselves, they would
give him much useful information ; and the
like may be said of the sensations we have
by all the other senses. [232]

As to the sensations and feelings that are
agreeable or disagreeable, they differ much
not only in degree, but in kind and in dig-
nity. Some belong to the animal part of
our nature, and are common to us with the
brutes ; others belong to the rational and
moral part. The first are more properly
called sensations ; the last, / elings. The
French word s°ntimcnt is common to both.*

The intention of nature in them is for the
most part obvious, and well deserving our
notice. It has been beautifully illustrated
by a very elegant French writer,* in his
" Theorie ries Sentiments Aqrmble-i"

The Author of Nature, in the distribution
of agreeable and painful feelings, hath
wisely and benevolently consulted the good
of the human species, and hath even shewn
us, by the same means, what tenor of con-
duct we ought to hold. For, first, The
painful sensations of the animal kind are
admonitions to avoid what would hurt us ;
and the agreeable sensations of this kind
invite us to those actions that are necessary
to the preservation of the individual or of
the kind. Secondly, By the same means,
nature invites us to moderate bodily exer-
cise, and admonishes us to avoid idleness
and inactivity on the one hand, and exces-
sive labour and fatigue on the other.

• Some French philosophers, since Keid, have
attempted the distinction of sentiment and sensation.

t Levesqtie de Pouilly H

Thirdly, The moderate exercise of all our
rational powers gives pleasure. Fourthly,
Every species of beauty is beheld with
pleasure, and every species of deformity
with disgust ; and we shall find all that we
call beautiful, to be something estimable or
useful in itself, or a sign of something that
is estimable or useful. Fifthly^ The bene-
volent affections are all accompanied with
an agreeable feeling, the malevolent with
the contrary. And, sixthly, The highest,
the noblest, and most durable pleasure is
that of doing well, and acting the part that
becomes us ; and the most bitter and pain-
ful sentiment, the anguish and remorse of
a gnilty conscience. These observations,
with regard to the economy of nature in
the distribution of our painful and agree-
able sensations and feelings, are illustrated
by the author last mentioned, so elegantly
and judiciously, that I shall not attempt to
say anything upon them after him. [233]

I shall conclude this chapter by observ-
ing that, as the confounding our sensations
with that perception of external objects
which is constantly conjoined with them,
lias been the occasion of most of the errers
and false theories of philosophers with re-
gard to the senses ; so the distinguishing
these operations seems to me to be the key
that leads to a right understanding of both.

Sensation, taken by itself, implies neither
the conception nor belief of any external
object. It supposes a sentient being, and
a certain manner in which that being is
affected ; but it supposes no more. Per-
ception implies an immediate conviction
and belief of something external — some-
thing different both from the mind that
perceives, and from the act of perception.
Things so different in their nature ought
to be distinguished ; but, by our constitu-
tion, they are always united. Every dif-
ferent perception is conjoined with a sensa-
tion that is proper to it. The one is the
sign, the other the thing signified. They
coalesce in our imagination. They are sig-
nified by one name, and are considered as
one simple operation. The purposes of life
do not require them to be distinguished.

It is the philosopher alone who has occa-
sion to distinguish them, when he would
analyse the operation compounded of them.
But he has no suspicion that there is any
composition in it ; and to discover this re-
quires a degree of reflection which has been
too little practised even by philosophers.

In the old philosophy, sensation and per-
ception were perfectly confounded. The
sensible species coming from the object, and
impressed upon the mind, was the whole;
and you might call it sensation or percep-
tion as you pleased*

This is not carreer; for, in (ho distinction of ihe
|"232, 233 J



Des Cartes and Locke, attending more
to the operations of their own minds, say,
that the sensations by which we have notice
of secondary qualities have no resemblance
to anything that pertains to body ; but they
did not seel hat this might, with equal justice,
be applied to the primary qualities. [234]
Mr Locke maintains, that the sensations we
have from primary qualities are resem-
blances of those qualities. This shews how
grossly the most ingenious men may err
with regard to the operations of their minds.
It must, indeed, be acknowledged, that it is
much easier to have a distinct notion of the
sensations that belong to secondary than
of those that belong to the primary quali-
ties.' The reason of this will appear in
the next chapter.

But, had jMr Locke attended with suffi-
cient accuracy to the sensations-f- which he
was every day and every hour receiving
from primary qualities, he would have seen
that they can as little resemble any quality
of an inanimated being as pain can resemble
a cube or a circle.

What had escaped this ingenious philo-
sopher, was clearly discerned by Bishop
Berkeley. He had a just notion of sensa-
tions, and saw that it was impossible that
anything in an insentient being could re-
semble them ; a thing so evident in itself,
that it seems wonderful that it should have
been so long unknown.

But let us attend to the consequence of
this discovery- Philosophers, as well as the
vulgar, had been accustomed to comprehend
both sensation and perception under one
name, and to consider them as one uncom-
pounded operation. Philosophers, even
more than the vulgar, gave the name of
sensation to the whole operation of the
senses ; and all the notions we have of ma-
terial things were called ideas of sensation.
This led Bishop Berkeley to take one in-
gredient of a complex operation for the
whole ; and, having clearly discovered the
nature of sensation, taking it for granted
that all that the senses present to the mind
is sensation, which can have no resemblance
to anything material, he concluded that
there is no material world. [235]

If the senses furnished us with no mate-
rials of thought but sensations, his conclu-
sion must be just ; for no sensation can give
us the conception of material things, far less

species impressa and species expressa, the distinc-
tion of sensation and perception could be perceived ;
but, in point offset, many even of the Aristotelians,
who admitted sppcies at ail, allowed them only in one
(,r two nf the senses. See No'esD* and M — H.

* The reader- will observe that Reid says, ** dis-
tinct notion of the sensations that helmig to the se-
condary qualities," and not distinct notion of the
secondary qualities themselves — H.

t Here again the reader will observe th it the term
is sensations, and not notions, of the primary qu. ili-


any argument to prove their existence. But,
if it is true that by our senses we have not
only a variety of sensations, but likewise a
conception and an immediate natural con-
viction of external objects, he reasons from
a false supposition, and his ' arguments fall
to the ground.*



The objects of perception are the various
qualities of bodies. Intending to treat of
these only in general, and chiefly with a view
to explain the notions which our senses
give us of them, I begin with the distinction
between primary and secondary qualities.
These were distinguished very early. The
Peripatetic system confounded them, and
left no difference. The distinction was again
revived by Des Cartes and Locke, and a
second time abolished by Berkeley and
Hume. If the real foundation of this dis-
tinction can be pointed out, it will enable us
to account for the various revolutions in the
sentiments of philosophers concerning it.

Every one knows that extension, divisi-
bility, figure, motion, solidity, hardness,
softness, and fluidity, were by Mr Locke
called primary qualities of body ; and that
sound, colour, taste, smell, and heat or cold,
were called &econdary qualities. Is there a
just foundation for this distinction ? Is
there anything common to the primary
which belongs not to the secondary ? And
what is it ?

I answer, That there appears to me to be
a real foundation for the distinction ; and it
is this — that our senses give us a direct and
a distinct notion of the primary qualities,
and inform us what they are in themselves.-!*
But of the secondary qualities, our senses
give us only a relative and obscure notion.
[236] They inform us only, that they are
qualities that affect us in a certain manner
— that is, produce in us a certain sensation ;
but as to what they are in themselves, our
senses leave us in the dark.:}:

* On this whole distinction, see Note D. * . — H
t By the expression, " what they are in tiieinselves, '
in reference to the primary qualities, and of " rela-
tivt lotion" in reference to the secondary, Reid
cannot mean that the former are known to us abso*
lutely and in themselves— that is, out of relation to our
cognitive faculties j fnr he elsewhere admits that all
our knowledge is relative. Farther, if *' our senses
give us a direct and distinct notion of the piimary
qualities ""d inform \ s what they are in themselves,"
these qualities, as known, must resemble* or be iden-
tical with, these qualities as existing. — H.

X The distinctions or nercepiion and sensation, and
of primary and secondary qualities, may be reduced
to one higher princ pie. Knowledge ispartly object*
ive, partly subjective,- both these elements are essen-
tial to every cognition, but in every cognition they
are always in the inverse raiio of e<scli other Nu«t>



[essay II,

Every man capable of reflection may
easily satisfy himself that he has a perfectly-
clear and distinct notion of extension, divisi-
bility, figure, and motion. The solidity of
a body means no more but that it excludes
other bodies from occupying the same place
at the same time Hardness, softness, and
fluidity are different degrees of cohesion in
the parts of a body. It is fluid when it has
no sensible cohesion ; soft, when the cohe-
sion is weak ; and hard, when it is strong.
Of the cause of this cohesion we are ignor-
ant, but the thing itself we understand per-
fectly, being immediately informed of it by
the sense of touch. It is evident, therefore,
that of the primary qualities we have a clear
and distinct notion ; we know what they
are, though we may be ignorant of their

I observed, farther, that the notion we
have of primary qualities is direct, and not
relative only. A relative notion of a thing,
is, strictly speaking, no notion of the thing
at all, but only of some relation which it
bears to something else.

Thus, gravity sometimes signifies the tend-
ency of bodies towards the earth ; some-
times it signifies the cause of that tendency.
When it means the first, I have a direct
and distinct notion of gravity ; I see it, and
feel it, and know perfectly what it is ; but
this tendency must have a cause. We give
the same name to the cause ; and that cause
has been an object of thought and of specu-
lation. Now, what notion have we of this
cause when we think and reason about it ?
It is evident we think of it as an unknown
cause, of a known effect. This is a relative
notion ; and it must be obscure, because it
gives us no conception of what the thing is,
but of what relation it bears to something
else. Every relation which a thing un-
known bears to something that is known,
may give a relative notion of it ; and there
are many objects of thought and of dis-
course of which our faculties can give no
better than a relative notion. [237]

Having premised these things to explain
what is meant by a relative notion, it is evi-
dent that our notion of primary qualities is
not of this kind ; we know what they are,
and not barely what relation they bear to
something else.

It is otherwise with secondary qualities.
If you ask me, what is that quality or mo-
dification in a rose which I call its smell, I
am at a loss to answer directly. Upon re-
flection, I find, that I have a distinct notion
of the sensation which it produces in my
mind. But there can be nothing like to
this sensation in the rose, because it is in-

in perception and Ibeprimary qualities, tlieobjective
do rtcnt preponderates, whereas the subjective ele-
ment preponderates in sensation and the secondary
SOalitirs. See Netcs 1) and D * .— II.

sentient. The quality in the rose is some-
thing which occasions the sensation in me ;
but what that something is, I know not.
My senses give me no information upon
this point. The only notion, therefore, my
senses give is this — that smell in the rose is
an unknown quality or modification, which
is the cause or occasion of a sensation which
I know well. The relation which this un-
known quality bears to the sensation with
which nature hath connected it, is all I learn
from the sense of smelling ; but this is
evidently a relative notion. The same rea-
soning will apply to every secondary quality.

Thus, I think it appears that there is a
real foundation for the distinction of pri-
mary from secondary qualities ; and that
they are distinguished by this — that of the
primary we have by our senses a direct and
distinct notion ; but of the secondary only
a relative notion, which must, because it is
only relative, be obscure ; they are con-
ceived only as the unknown causes or occa-
sions of certain sensations with which wo
are well acquainted.

The account I have given of this distinc-
tion is founded upon no hypothesis. [238]
Whether our notions of primary qualities
are direct and distinct, those of the se-
condary relative and obscure, is a matter
of fact, of which every man may have cer-
tain knowledge by attentive reflection upon
them. To this reflection I appeal, as the
proper test of what has been advanced, and
proceed to make some reflections on this

1- The primary qualities are neither sens-
ations, nor are they resemblances of sens-
ations. This appears to me self-evident.
I have a clear and distinct notion of each of
the primary qualities. I have a clear and
distinct notion of sensation. I can com-
pare the one with the other ; and, when I
do so, I am not able to discern a resembling
feature. Sensation is the act or the feeling
(I dispute not which) of a sentient being.
Figure, divisibility, solidity, are neither
acts nor feelings. Sensation supposes a
sentient being as its subject ; for a sensa-
tion that is not felt by some sentient being,
is an absurdity. Figure and divisibility
supposes a subject that is figured and divi-
sible, but not a subject that is sentient.

2. We have no reason to think that any
of the secondary qualities resemble any sens-
ation. The absurdity of this notion has
been clearly shewn by Des Cartes, Locke,
and many modern philosophers. It was a
tenet of the ancient philosophy, and is still
by many imputed to the vulgar, but only as
a vulgar error. It is too evident to need
proof, that the vibrations of a sounding
body do not resemble the sensation of sound,
nor the effluvia of an odorous body the sens-
ation of smell.

[ 237, 2381

CHAP. XV11.]



3. The distinctness of our notions of pri-
mary qualities prevents all questions and
disputes about their nature. There are no
different opinions about the nature of ex-
tension, figure, or motion, or the nature of
any primary quality. Their nature is man-
ifest to our senses, and cannot be unknown
to any man, or mistaken by him, though
their causes may admit of dispute. [239]

The primary qualities are the object of
the mathematical sciences; and the dis-
tinctness of our notions of them enables
us to reason demonstratively about them to
a great extent. Their various modifications
are precisely defined in the imagination, and
thereby capable of being compared, and their
relations determined with precision and cer-

It is not so with secondary qualities.
Their nature not being manifest to the sense,
maybe a subject of dispute. Our feeling
informs us that the fire is hot ; but it does
not inform us what that heat of the fire is.
But does it not appear a contradiction, to
say we know that the fire is hot, but we
know not what that heat is ? I answer,
there is the same appearance of contradic-
tion in many things that must be granted.
We know that wine has an inebriating qua-
lity ; but we know not what that quality is.
Jt is true, indeed, that, if we had not some
notion of what is meant by the heat of fire,
and by an inebriating quality, we could
affirm nothing of either with understand-
ing. We have a notion of both ; but it ■ is
only a relative notion. We know that they
are the causes of certain known effects.

4. The nature of secondary qualities is a
proper subject of philosophical disquisition ;
and in this philosophy has made some pro-
gress. It has been discovered, that the
sensation of smell is occasioned by the
effluvia of bodies; that of sound by their
vibration. The disposition of bodies to re-
flect a particular kind of light, occasions the
sensation of colour. Very curious dis-
coveries have been made of the nature of
heat, and an ample field of discovery in
these subjects remains.

5. We may see why the sensations be-
longing to secondary qualities are an object
of our attention, while those which belong
to the primary are not.

The first are not only signs of the ob-
ject perceived, but they bear a capital part
in the notion we form of it. [240] We
conceive it only as that which occasions such
a sensation, and therefore cannot reflect
upon it without thinking of the sensation
which it occasions : we have no other mark
whereby to distinguish it. The thought of
a secondary quality, therefore, always car-
ries us back to the sensation which it pro-
duces. We give the same *name to both,
and are apt to confound them together.

But, having a clear and distinct conception
of primary qualities, we have no need, when
we think of them, to recall their sensations.
When a primary quality is perceived, the
sensation immediately leads our thought to
the quality signified by it, and is itself for-
got. We have no occasion afterwards to

Online LibraryThomas ReidThe works of Thomas Reid, D.D.; now fully collected, with selections from his umpublished letters → online text (page 71 of 114)