Thomas Reid.

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

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that words or signs should be exactly like
the things signified by them.-|-

These two opinions, I think, cannot be
reconciled. For, if the images or traces in
the brain are perceived,} they must be the

thing more than a modification of the mind itself.—

* But not in Reid's exclusive sense of the word
Idea.— H.

t The non-negation, in this instance, of all re-
semblance between the material Ideas, or organic
motions in the brain, and the external reality, is one
of the occasional instances of Des Cartes's reticence of
his subordinate doctrines, in order to avoid all useless
tilting against prevalent opinions. Another is his
sometimes giving to these motions the name of Spe-
cies.— H.

$ Which, in Des Cartes' doctrine, they arc not.— H.
["137, 1381



objects of perception, and not the occasions
of it only. On the other hand, if they are
only the occasions of our perceiving, they
are not perceived at all. Des Cartes seems
to have hesitated between the two opinions,
or to have passed from the one to the
other.* Mr Locke seems, in like manner,
to have wavered between the two ; some-
times representing the ideas of material
things as being in the brain, but more fre-
quently as in the mind itself, -f- [139]
Neither Des Cartes nor Mr Locke could,
consistently with themselves, attribute any
other qualities to images in the brain but
extension, figure, and motion ; for as to
those qualities which Mr Locke distin-
guished by the name of secondary qualities,
both philosophers believed them not to be-
long to body at all,$ and, therefore, could
not ascribe them to images in the brain. §

Sir Isaac Newton and Dr Samuel Clarke
uniformly speak of the species or images of
material things as being in that part of the
brain called the sensorium, and perceived
by the mind there present ; but the former
speaks of this point only incidentally, and
with his usual modesty, in the form of a
query. || Malebranche is perfectly clear and
unambiguous in this matter. According to
his system, the images or traces in the
brain are not perceived at all — they are
only occasions upon which, by the laws of
Nature, certain sensations are felt by us,
and certain of the divine ideas discovered to
our minds.

The second point on which Des Cartes
seems to waver, is with regard to the credit
that is due to the testimony of our senses.

Sometimes, from the perfection of the
Deity, and his being no deceiver, he infers
that our senses and our other faculties can-
not be fallacious ; and since we seem clearly
to perceive that the idea of matter comes
to us from things external, which it per-
fectly resembles, therefore we must con-
clude that there really exists something
extended in length, breadth, and depth,
having all the properties which we clearly
perceive to belong to an extended thing.

At other times, we find Des Cartes and
his followers making frequent complaints,

• Des Cartes had only one opinion on the point.
The difficulty which perplexes Reid arose from his
want of a systematic comprehension of the Cartesian
philosophy, and his being unaware that, by Ideas,
Des Cartes designated two very different things— vif.,
the proximate bodily antecedent, and the mental
consequent.— H.

f Locke's opinion, if he had a precise one on the
matter, it is impossible to ascertain. See Note O —

t See above, p. 205, note * — H.

§ Yet Locke expressly denies them to be modifica-
tions of mind. See Note O — H.

|| Reid is correct in all he here says of Newton and
Clarke j it u indeed virtually admitted by Clarke
himself, in his controversy wiih Leibnitz. Compare
Leibnitii Opera, II., p. 161, and p. 18s! — H.
["139, HO]

as all the ancient philosophers did, of the
fallacies of sense. He warns us to throw
off its prejudices, and to attend only with
our intellect, to the ideas implanted there.
By this means we may perceive, that the
nature of matter does not consist in hard-
ness, colour, weight, or any of those things
that affect our senses, but in this only, that
it is something extended in length, breadth,
and depth. [140] The senses, he says,
are only relative to our present state ; they
exhibit things only as they tend to profit
or to hurt us, and rarely, and by accident
only, as they are in themselves. *

It was probably owing to an aversion to
admit anything into philosophy, of which
we have not a clear and distinct concep-
tion, that Des Cartes was led to deny that
there is any substance of matter distinct from
those qualities of it which we perceive.-)-
We say that matter is something extended,
figured, moveable. Extension, figure, mo-
bility, therefore, are not matter, but quali-
ties, belonging to this something, which
we call matter. Des Cartes could not
relish this obscure something, which is sup-
posed to be the subject or substratum of
those qualities ; and, therefore, maintained
that extension is the very essence of mat-
ter. But, as we must ascribe extension to
space as well as to matter, he found him-
self under a necessity of holding that space
and matter are the same thing, and differ
only in our way of conceiving them ; so
that, wherever there is space there is mat-
ter, and no void left in the universe. The
necessary consequence of this is, that the
material world has no bounds nor limits.
He did not, however, choose to call it in-
finite, but indefinite.

It was probably owing to the same cause
that Des Cartes made the essence of the
soul to consist in thought. He would not
allow it to be an unknown something that
has the power of thinking ; it cannot, there-
fore, be without thought ; and, as he con-
ceived that there can be no thought with-
out ideas, the soul must have had ideas in
its first formation, which, of consequence,
are innate. $

The sentiments of those who came after
Des Cartes, with regard to the nature of
body and mind, have been various. Many
have maintained that body is only a collec-
tion of qualities to which we give one

• But see " Principia," $ 66, sqq.— H.

t See Stewart's " Elements," I., Note A ; Royer
Collard's Fragment, VIII.— H.

t The doctrine of Des Cartes, in relation to lunate
Ideas, has been very generally misunderstood ; and
by no one more than by Locke. What it really
amounted to, is clearly stated in his strictures on
the Program of Regius. Justice has latterly been
done him, among others, by Mr. Stewart, in his " Dis.
sertation," and by M. Laiomiguiere, in his " Cours."
See also the old controversy ot De Vries with Hue]]
on this point. — H.



[essav II.

name ; and that the notion of a subject of
inhesion, to which those qualities belong,
is only a fiction of the mind.* [141]
Some hare even maintained that the sonl
is only a succession of related ideas, with-
out any subject of inhesion. + It appears,
by what has been said, how far these no-
tions are allied to the Cartesian system.

The triumph of the Cartesian system
over that of Aristotle, is one of the most
remarkable revolutions in the history of phi-
losophy, and has led me to dwell longer
upon it than the present subject perhaps
required. The authority of Aristotle was
now no more. That reverence for hard
words and dark notions, by which men's
understanding had been strangled in early
years, was turned into contempt, and every-
thing suspected which was not clearly and
distinctly understood. This is the spirit of
the Cartesian philosophy, and is a more
important acquisition to mankind than any
of its particular tenets; and for exerting
this spirit so zealously, and spreading it so
successfully, Des Cartes deserves immortal

It is to be observed, however, that Des
Cartes rejected a part only of the ancient
theory, concerning the perception of ex-
ternal objects by the senses, and that he
adopted the other part. That theory may
be divided into two parts : The first, that
images, species, orforms of externalobjects,
come from the object, and enter by the
avenues of the senses to the mind; the
second part is, That the external object
itself is not perceived, but only the species
or image of it in the mind. The first part
Des Cartes and his followers rejected, and
refuted by solid arguments ; but the second
part, neither he nor his followers have
thought of calling in question ; being per-
suaded that it is only a representative
image in the mind of the external object
that we perceive, and not the object itself.
And this image, which the Peripatetics
called a species, he calls an idea, changing
the name only, while he admits the thing. J

It seems strange that the great pains
which this philosopher took to throw off the
prejudices of education, to dismiss all his
former opinions, and to assent to nothing,
till he found evidence that compelled his
assent, should not have led him to doubt of
this opinion of the ancient philosophy. It
is evidently a philosophical opinion ; for the
vulgar undoubtedly believe that it is the

* As Locke, (but he Is not consistent,) Law,
Green, Watts, and others. See Cousin, " Cours de
Philosophic," Tome II., Legem xviii. — H.

t Hume— H

X Des Cartes and Beid coincide in doctrine, if
Reid holds that we know the extended and exter-
nal object only, by a conception or subjective modifi-
tion of the percipient mind. See Notes N and C. — H.

external object which we immediately per-
ceive, and not a representative image of it
only. It is for this reason that they look
upon it as perfect lunacy to call in question
the existence of external objects.*

It seems to be admitted as a first. prin-
ciple, by the learned and the unlearned, that
what is really perceived must exist, and that
to perceive what does not exist is impossible.
So far the unlearned man and the philoso-
pher agree. The unlearned man says — I
perceive the external object, and I perceive
it to exist. Nothing can be more absurd
than to doubt of it. The Peripatetic says —
What I perceive is the very identical form
of the object, which came immediately from
the object, and makes an impression upon
my mind, as a seal does upon wax ; and,
therefore, I can have no doubt of the ex-
istence of an object whose form I perceive. ■(■
But what says the Cartesian ? I perceive
not, says he, the external object itself. So
far he agrees with the Peripatetic, and differs
from the unlearned man. But I perceive
an image, or form, or idea, in my own
mind, or in my brain. I am certain of the
existence of the idea, because I imme-
diately perceive it - f- But how this idea is
formed, or what it represents, is not self-
evident; and therefore I must find argu-
ments by which, from the existence of the
idea which I perceive, I can infer the ex-
istence of an external object which it re-

As I take this to be a just view of the
principles of the unlearned man, of the Peri-
patetic, and of the Cartesian, so I think
they all reason consequentially from their
several principles : that the Cartesian has
strong grounds to doubt of the existence of
external objects ; the Peripatetic very little
ground of doubt ; and the unlearned [143]
man none at all : and that the difference of
their situation arises from this — that the un-
learned man has no hypothesis ; the Peri-
patetic leans upon an hypothesis ; and the
Cartesian upon one half of that hypothesis.

Des Cartes, according to the spirit of his
own philosophy, ought to have doubted of
both parts of the Peripatetichypothesis, or to
have given his reasons why he adopted one
part, as well as why he rejected the other

* This is one of the passages which favour the
opinion that Reid did suppose the non-ego to be
known in itself as existing, and not only in and
through the ego ; tor mankind in general believe
that the extended reality, as perceived, is something
more than a mere internal representation by the
mind, suggested in consequence of the impression
made by an unknown something on the sense. See
Note C— H.

f The Peripatetic and the Cartesian held that the
species or idea was an object of consciousness. If
Reid understood the language he uses, he must bold
that the external and extended reality is an object of
consciousness. But this does not quadrate with his
doctrine, that we only know extension and figure by
a suggested conception in the mind. See Note C— H.




part ; especially, since the unlearned, who
have the faculty of perceiving objects by
their senses in no less perfection than
philosophers, and should, therefore, know,
as well as they, what it is they perceive,
have been unanimous in this, that the
objects they perceive are not ideas in their
own minds, but things external. It might
have been expected that a philosopher who
was so cautious as not to take his own ex-
istence for granted without proof, would not
have taken it for granted without proof,
that everything he perceived was only ideas
in his own mind.

But, if Des Cartes made a rash step in
this, as I apprehend he did, he ought not
to bear the blame alone. His successors
have still continued in the same track, and,
after his example, have adopted one part of
the ancient theory — to wit, that the objects
we immediately perceive are ideas only. All
their svstems are built on this foundation.



The reputation which Locke's " Essay on
Human Understanding" had at home from
the beginning, and which it has gradually
acquired abroad, is a sufficient testimony of
its merit. [144] There is, perhaps, no
book of the metaphysical kind that has been
so generally read by those who understand
the language, or that is more adapted to
teach men to think with precision,* and to
inspire them with that candour and love of
truth which is the genuine spirit of philo-
sophy. He gave, I believe, the first ex-
ample in the English language of writing
on such abstract subjects, with a remarkable
degree of simplicity and perspicuity ; and
in this he has been happily imitated by
others that came after him. No author
hath more successfully pointed out the
danger of ambiguous words, and the im-
portance of having distinct and determin-
ate notions in judging and reasoning. His
observations on the various powers of the
human understanding, on the use and abuse
of words, and on the extent and limits of
human knowledge, are drawn from atten-
tive reflection on the operations of his own
mind, the true source of all real knowledge
on these subjects ; and shew an uncommon
degree of penetration and judgment. But
he needs no panegyric of mine, and I men-
tion these things, only that, when I have
occasion to differ from him, I may not be
thought insensible of the merit of an author
whom I highly respect, and to whom I owe

* To praise Locke for precision, is rather too
much— H.
[144, 145]

my first lights in those studies, as well as
my attachment to them.

He sets out in his essay with a full con-
viction, common to him with other philo-
sophers, that ideas in the mind are the
objects of all our thoughts in every opera-
tion of the understanding. This leads him
to use the word idea" so very frequently,
beyond what was usual in the English
language, that he thought it necessary, in
his introduction, to make this apology : —
" It being that term,'' says he, " which, I
I think, serves best to stand for whatsoever
is the object of understanding when a man
thinks, I have used it to express whatever
is meant by phantasm, notion, species, or
whatever it is which the mind can be em-
ployed about in thinking ; and I could not
avoid frequently using it. I presume it
will be granted me, that there are such
ideas in men's minds ; every man is con-
scious of them in himself, and men's words
and actions will satisfy him that they are in
others." [145]

Speaking of the reality of our knowledge,
he says, " It is evident the mind knows not
things immediately, but only by the inter-
vention of the ideas it has of them. Our
knowledge, therefore, is real, only so far as
there is a conformity between our ideas and
the reality of things. But what shall be
here the criterion ? How shall the mind,
when it perceives nothing but its own ideas,
know that they agree with things them-
selves ? This, though it seems not to want
difficulty, yet, I think, there be two sorts
of ideas that we may be assured agree with

We see that Mr Locke was aware, no
less than Des Cartes, that the doctrine of
ideas made it necessary, and at the same
time difficult, to prove the existence of a
material world without us; because the
mind, according to that doctrine, perceives
nothing but a world of ideas in itself. Not
only Des Cartes, but Malebranche, Arnauld,
and Norris, had perceived this difficulty,
and attempted to remove it with little suc-
cess. Mr Locke attempts the same thing ;
but his arguments are feeble. He even
seems to be conscious of this ; for he con-
cludes his reasoning with this observation
— " That we have evidence sufficient to
direct us in attaining the good and avoiding
the evil, caused by external objects, and
that this is the important concern we have
in being made acquainted with them." This,
indeed, is saying no more than will be
granted by those who deny the existence of
a material world.

As there is no material difference between

* Locke may be said to have first naturalized the
ward in English philosophical language, in its Caite-
sian extension. — H.

T 2



[essay II.

Locke and Des Cartes with regard to the
perception of objects by the senses, there
is the less occasion, in this place, to take
notice of all their differences in other points-
They differed about the origin of our ideas.
Des Cartes thought some of them were
innate ; the other maintained that there
are no innate ideas, and that they are all
derived from two sources — to wit, sensation
and reflection ; meaning, by sensation, the
operations of our exterrfal senses ; and, by
reflection, that attention which we are
capable of giving to the operations of our
own minds. [146]

They differed with regard to the essence
both of matter and of mind : the British
philosopher holding that the real essence of
both is beyond the reach of human know-
ledge ; the other conceiving that the very
essence of mind consists in thought, and
that of matter in extension, by which he
made matter andspacenottodifferin reality,
and no part of space to be void of matter.

Mr Locke explained, more distinctly than
had been done before, the operations of the
mind in classing the various objects of
thought, and reducing them to genera and
species. He was the first, I think, who
distinguished in substances what he calls
the nominal essence — which is only the
notion we form of a genus or species, and
which we express by a definition — from the
real essence or internal constitution of the
thing, which makes it to be what it is.*
Without this distinction, the subtile dis-
putes which tortured the schoolmen for so
many age's, in the controversy between the
nominalists and realists, could never be
brought to an issue. He shews distinctly
how we form abstract and general notions,
and the use and necessity of them in rea-
soning. And as (according to the received
principles of philosophers) every notion of
our mind must have for its object an idea
in the mind itself, -|- he thinks that we form
abstract ideas by leaving out of the idea of
an individual everything wherein it differs
from other individuals of the same species
or genus ; and that this power of forming
abstract ideas, is that which chiefly dis-
tinguishes us from brute animals, in whom
he eould see no evidence of any abstract

Since the time of Des Cartes, philoso-
phers have differed much with regard to the
share they ascribe to the mind itself, in the
fabrication of those representative beings
called ideas, and the manner m which this
work is carried on.

* Locke has no originality in this respect. — H.

\ Notion is here used for the apprehension of the
idea, or representative reality, which Reid supposed
that all philosophers viewed as something more than
the mere act of knowledge, considered in relation to
what was, through it, known or represented. — H,

Of the authors I have met with, Dr
Robert Hook is the most explicit. He was
one of the most ingenious and active mem-
bers of the Royal Society of London at its
first institution ; and frequently read lec-
tures to the Society, which were published
among his posthumous works. [147] In his
" Lectures upon Light," § 7, he makes
ideas to be material substances ; and thinks
that the brain is furnished with a proper
kind of matter for fabricating the ideas of
each sense. The ideas of sight, he thinks,
are formed of a kind of matter resembling
the Bononian stone, or some kind of phos-
phorus ; that the ideas of sound are formed
of some matter resembling the chords or
glasses which take a sound from the vibra-
tions of the air ; and so of the rest. .

The soul, he thinks, may fabricate some
hundreds of those ideas in a day ; and that,
as they are formed, they are pushed farther
off from the centre of the brain where the
soul resides. By this means they make a con-
tinued chain of ideas, coyled up in the brain ;
the first end of which is farthest removed
from the centre or seat of the soul, and the
other end is always at the centre, being the
last idea formed, which is always present
the moment when considered ; and, there-
fore, according as there is a greater number
of ideas between the present sensation or
thought in the centre and any other, the
soul is apprehensive of a larger portion of
time interposed.

Mr Locke has not entered into so minute
a detail of this manufacture of ideas ; but he
ascribes to the mind a very considerable
hand in forming its own ideas. With re-
gard to our sensations, the mind is passive,
" they being produced in us, only by dif-
ferent degrees and modes of motion in our
animal spirits, variously agitated by ex-
ternal objects." These, however, cease to
be as soon as they cease to be perceived ;
but, by the faculties of memory and imagin-
ation, " the mind has an ability, when it
wills, to revive them again, and, as it were,
to paint them anew upon itself, though
some with more, some with less difficulty."

As to the ideas of reflection, he ascribes
them to no other cause but to that attention
which the mind is capable of giving to its
own operations. These, therefore, are
formedbythe mind itself. [148] Heascribes
likewise to the mind the power of com-
pounding its simple ideas into complex ones
of various forms ; of repeating them, and
adding the repetitions together ; of dividing
and classing them ; of comparing them,
and, from that comparison, of forming the
ideas of their relation j nay, of forming a
general idea of a species or genus, by taking
from the idea of an individual everything
by which it is distinguished from other in.
dividuals of the kind, till at last it becomes





an abstract general idea, common to all the
individuals of the kind.

These, I think, are the powers which Mr
Locke ascribes to the mind itself in the
fabrication of its ideas. Bishop Berkeley,
as we shall see afterwards, abridged them
considerably, and Mr Hume much more.

The ideas we have of the various quali-
ties of bodies are not all, as Mr Locke
thinks, of the same kind. Some of them
are images or resemblances of what is really
in the body; others are not. There are
certain qualities inseparable from matter;
iuch as extension, solidity, figure, mobility.
Our ideas of these are real resemblances of
the qualities in the body ; and these he
calls primary qualities. But colour, sound,
taste, smell, heat, and cold, he calls second-
ary qualities, and thinks that they are
only powers in bodies of producing cer-
tain sensations in us ; which sensations
have nothing resembling them, though they
are commonly thought to be exact resem-
blances of something in the body. " Thus,"
says he, " the idea of heat or light, which
we receive, by our eye or touch, from the
sun, are commonly thought real qualities
existing in the sun, and something more
than mere powers in it."

The names of primary and secondary
qualities were, I believe, first used by Mr
Locke ; but the distinction which they ex-

Online LibraryThomas ReidThe works of Thomas Reid, D.D.; now fully collected, with selections from his umpublished letters → online text (page 62 of 114)