for the distinction of the primary from the secondary qualities of
bodies. They are primary in the order of our definition of matter;
and they are felt by us as peculiarly permanent, independently of our
feelings, which they seem at every moment ready to awake. The power
of affecting us with smell, taste, sight, or hearing, may or may not
be present; but the power of exciting the feelings of extension and
resistance is constantly present, and is regarded by us as essential
to our very notion of matter,--or, in other words, we give the name
of _matter_, only where this complex perception is excited in us. We
seem, therefore, to be constantly surrounded with a material world
of substances extended and resisting, that is to say, a world of
substances capable of exciting in us the feelings which are ascribed
to the primary quality of matter;--but still the feeling of these
primary qualities, which we regard as permanent, is not less than the
feeling of the secondary qualities, a state or affection of the mind,
and nothing more;--and in the one case, as much as in the other, in
the perception of the qualities termed secondary, as much as of the
qualities termed primary, the feeling, when it occurs, is the direct or
immediate result of the presence of the external body with the quality
of which it corresponds;--or, if there be any difference in this
respect, I conceive that our feeling of fragrance, or sweetness, was,
originally at least, a more immediate result of the presence of odorous
or sapid particles,--than any feeling of extension, without the mind,
was the effect of the first body which we touched.
To the extent which I have now stated, then, the difference of these
classes of qualities may be admitted. But as to the other differences
asserted, they seem to be founded on a false view of the nature of
perception. I cannot discover any thing in the sensations themselves,
corresponding with the primary and secondary qualities, which is
direct, as Dr Reid says, in the one case, and only relative in the
other. All are _relative_, in his sense of the term, and equally
relative,--our perception of extension and resistance, as much as our
perception of fragrance or bitterness. Our feeling of extension is not
itself matter, but a feeling excited by matter. We ascribe, indeed, our
sensations as effects to external objects that excite them; but it is
only by the medium of our sensations that these, in any case, become
known to us as objects. To say that our perception of extension is
not relative, to a certain external cause of this perception, direct
or indirect, as our perception of fragrance is relative to a certain
external cause, would be to say that our perception of extension,
induced by the presence of an external cause, is not a _mental_
phenomenon, as much as the perception of fragrance, but is something
more than a state of the mind; for, if the perception of extension be,
as all our perceptions and other feelings must surely be, a _mental_
phenomenon, a state of _mind_, not of _matter_, the reference made
of this to an external cause, must be only to something which is
conceived relatively as the cause of this feeling. What matter is
independently of our perception, we know not, and cannot know, for it
is only by our sensations that we can have any connexion with it; and
even though we were supposed to have our connexion with it enlarged,
by various senses additional to those which we possess at present,
and our acquaintance with it, therefore, to be far more minute, this
very knowledge, however widely augmented, must itself be a _mental
phenomenon_, in like manner, the reference of which, to matter, as
an external cause, would still be _relative_ only like our present
knowledge. That the connexion of the feeling of extension, with a
corporeal substance really existing without, depends on the arbitrary
arrangement made by the Deity; and that all of which we are conscious
might, therefore, have existed, as at present, though no external cause
had been, Dr Reid, who ascribes to an intuitive principle, our belief
of an external universe, virtually allows; and this very admission
surely implies, that the notion does not, directly and necessarily,
involve the existence of any particular cause, whatever it may be
in itself, by which the Deity has thought proper to produce the
corresponding feeling of our mind. It is quite evident, that we cannot,
in this case, appeal to experience, to inform us what sensations
or perceptions are more or less direct; for experience, strictly
understood, does not extend beyond the feelings of our own mind, unless
in this very relative belief itself, that there are certain external
causes of our feelings,--causes which it is impossible for us not to
conceive as really existing, but of which we know nothing more than
that our feelings, in all that wide variety of states of mind, which
we express briefly by the terms sensation or perception, are made to
depend on them. In the series of states in which the mind has existed,
from the first moment of our life, to the present hour, the feelings
of extension, resistance, joy, sorrow, fragrance, colour, hope, fear,
heat, cold, admiration, resentment, have often had place; and some
of these feelings, it has been impossible for us not to ascribe to a
direct external cause; but there have not been in the mental series,
which is all of which we can be conscious, both that feeling of the
mind which we term the perception of extension, and also body itself,
as the cause of this feeling; for body, as an actual substance, cannot
be a part of the consciousness of the mind, which is a different
substance. It is sufficient for us to believe, that there are external
causes of this feeling of the mind, permanent and independent of it,
which produce in regular series, all those phenomena that are found by
us in the physical events of the universe, and with the continuance of
which, therefore, our perceptions also will continue; we cannot truly
suppose more, without conceiving our very notion of extension, a mental
state, to be itself a body extended, which we have as little reason to
suppose, as that our sensation of fragrance, another mental state, is
itself a fragrant body. It is needless to prolong this discussion, by
endeavouring to place the argument in new points of view. The simple
answer to the question, “Is our notion of extension, or of the other
primary qualities of matter, a phenomenon or affection of matter or
of mind?” would be of itself sufficient; for if it be a state of the
_mind_, as much as our feeling of heat or of fragrance, and a state
produced by the presence of an external cause, as our sensations of
heat or fragrance are produced, then there is no reason to suppose,
that the knowledge is, in one case, more direct than in the other. In
both, it is the effect of the presence of an external cause, and in
both it must be _relative_ only,--to adopt Dr Reid's phrase,--to that
particular cause which produced it; the knowledge of which cause, in
the case of extension, as much as in the case of fragrance, is nothing
more than the knowledge, that there is _without_ us, something which
is not our mind itself, but which exists, as we cannot but believe,
permanently and independently of our mind, and produces according to
its own varieties, in relation to our corporeal frame at one time, that
affection of the mind which we denominate the perception of extension;
at another time, that different affection of the mind, which we
denominate the perception of fragrance. _What it is_, as it exists in
absolute independence of our perceptions, we who become acquainted with
it, only by those very perceptions, know not, in either case; but we
know it at least,--which is the only knowledge important for us,--as it
exists _relatively_ to _us_; that is to say, it is impossible for us,
from the very constitution of our nature, not to regard the variety of
our perceptions, as occasioned by a corresponding variety of causes,
external to our mind; though, even in making this reference, we must
still believe our perceptions themselves, to be altogether different
and distinct from the external causes, whatever they may be, which have
produced them; to be, in short, phenomena purely mental, and to be this
equally, whether they relate to the primary or the secondary qualities
of matter; our notion of extension, in whatever way the Deity may have
connected it with the presence of external things, being as much a
state of the mind itself, as our notion of sweetness or sound.
These observations, on the process of suggestion, which, in the
reference to an external cause, distinguishes our _perceptions_ from
our _simpler sensations_,--and on the real and supposed differences
of the primary and secondary qualities of matter,--will have prepared
you, I trust, for understanding better the claim which Dr Reid has made
to the honour of overthrowing what he has termed the ideal system of
perception. It is a claim, as I have said, which appears to me truly
wonderful, both as made by him and admitted by others; the mighty
achievement which appeared to him to be the overthrow of a great
system, being nothing more, than the proof that certain phrases are
metaphorical, which were intended by their authors to be understood
only as metaphors.
In perception there is, as I have already frequently repeated, a
certain _series_--the presence of an external object--the affection of
the sensorial organ--the affection of the sentient mind. As the two
last, however, belong to one being--the being called _self_--which
continues the same, while the external objects around are incessantly
changing;--it is not wonderful, that, in speaking of perception, we
should often think merely of the object as one, and of _ourself_, (this
compound of mind and matter,) as also one,--uniting the organic and
mental changes, in the single word which expresses our perception. To
see and to hear, for example, are single words, expressive of this
whole process--the bodily as well as the mental part--for we do not
consider the terms as applicable, in strict philosophic propriety,
to cases, in which the mere mental affection is the same, but the
corporeal part is believed by us to be different,--as in sleep, or
reverie, when the castle, the forest, the stream, rise before us as in
reality, and we feel as if we were truly listening to voices which we
love. That we feel, as if we were listening, and feel as if we saw, is
our language, when, in our waking hours, we speak of this phenomena of
our dreams,--not that we actually _saw_ and _heard_--thus evidently
shewing, that we comprehend, in these terms,--when used without the
qualifying words _as if_--not the mental changes of state only, but
the whole process of perception, corporeal as well as mental. The mere
organic part of the process, however, being of importance, only as
it is followed by the mental part,--and being always followed by the
mental part,--scarcely enters into our conception, unless in cases
of this sort, when we distinguish perception from vivid imagination,
or when the whole compound process of perception is a subject of
our philosophic inquiry. As sight, hearing, perception, involve, in
a single word,--process both mental and corporeal,--so, I have no
doubt, that idea, though now confined more strictly to the feelings
of the mind, was long employed with a more vague signification, so
as sometimes to mean the mental affection, sometimes the organic
affection, sometimes both;--in the same manner, as at present we speak
of sight, sometimes as mental, sometimes as organic, sometimes as
_both_. It comprehends both, when we distinguish the mountain or forest
which we _see_, from the mountain or forest of which we _dream_. It is
_mental_ only, when we speak of the pleasure of sight. It is organic
only, when we say of an eye, in which the passage of the rays of light
has become obstructed, that its _sight_ is lost, or has been injured by
disease.
The consideration of this double sense of the term _idea_, in some of
the older metaphysical writers, corresponding with our present double
sense of the word perception, as involving both the corporeal and
mental part of the process, removes, I think, much of that apparent
confusion, which is sometimes to be found in their language on the
subject; when they combine with the term expressions, which can be
understood only in a _material_ sense, after combining with it, at
other times, expressions, which can be understood only of the _mind_;
as it is not impossible that a period may arrive, when much of our
reasoning, that involves no obscurity at present, may seem obscure
and confused, to our successors, in that career of inquiry, which,
perhaps, is yet scarcely begun; merely because they may have limited,
with stricter propriety, to one part of a process, terms, which we
now use as significant of a whole process. In the same manner, as we
now exclude wholly from the term _idea_ every thing _organic_, so may
every thing organic hereafter be excluded from the term _sight_; and
from the simple phrase, so familiar at present, that an eye has lost
its sight, some future philosopher may be inclined to assert, that we,
who now use that phrase, consider the perception of vision, as in the
_material organ_; and, if he have the talents of Dr Reid, he may even
form a series of admirable ratiocinations, in disproof of an opinion
which nobody holds, and may consider himself, and perhaps, too, if he
be as fortunate as the author of the Inquiry into the Human Mind, may
be considered, by others, as the overthrower of a mighty system of
metaphysical illusion.
How truly this has been the case, in the supposed overthrow of the
ideal system, I shall proceed to shew in my next Lecture.
FOOTNOTE:
[92] On the Intellectual Powers, Essay II. c. 17.
LECTURE XXVI.
ON DR REID'S SUPPOSED CONFUTATION OF THE IDEAL SYSTEM; HYPOTHESIS
OF THE PERIPATETICS REGARDING PERCEPTION; AND OPINIONS OF VARIOUS
PHILOSOPHERS ON THE SAME SUBJECT.
The remarks which I offered, in my last Lecture, in illustration of
what have been termed the _primary_ and _secondary_ qualities of
matter, were intended chiefly to obviate that false view of them, in
which the one set of these qualities is distinguished, as affording
us a knowledge that is direct, and the other set, a knowledge that is
relative only;--as if any qualities of matter could become known to
the mind, but as they are capable of affecting the mind with certain
feelings, and as _relative_, therefore, to the feelings which they
excite. What matter is, but as the cause of those various states of
mind, which we denominate our sensations or perceptions, it is surely
impossible for us, by perception, to discover. The physical universe,
amid which we are placed, may have innumerable qualities that have no
relation to our percipient mind,--and qualities, which, if our mind
were endowed with other capacities of sensation, we might discover as
readily as those which we know at present; but the qualities that have
_no relation_ to the present state of the mind, cannot to the mind,
in its present state, be elements of its knowledge. From the very
constitution of our nature, indeed, it is impossible for us not to
believe, that our sensations have _external_ causes, which correspond
with them, and which have a permanence, that is independent of our
transient feelings,--a permanence, that enables us to predict in
certain circumstances, the feelings which they are again to excite in
our percipient mind; and to the union of all these permanent external
causes, in one great system, we give the name of the material world.
But the material world, in the sense in which alone we are entitled to
speak of it, is still only a name for a multitude of external causes
of our feelings,--of causes which are, recognized by us as permanent
and uniform in their nature; but are so recognized by us, only because,
in similar circumstances, they excite uniformly in the mind the same
perceptions, or, at least, are supposed by us to be uniform in their
own nature, when the perceptions which they excite in us are uniform.
It is according to their mode of affecting the mind, then, with various
sensations, that we know them,--and not according to their own absolute
nature, which it is impossible for us to know,--whether we give the
name of primary or secondary to the qualities which affect us. If
our sensations were different, our perceptions of the qualities of
things, which induce these sensations in us, would instantly have a
corresponding difference. All the external existences, which we term
matter,--and all the phenomena of their motion or their rest,--if known
to us at all, are known to us only by exciting in _us_, the percipients
of them, certain feelings:--and qualities, which are not more or less
directly _relative_ to our feelings, as sentient or percipient beings,
are, therefore, qualities which _we_ must be forever incapable even of
divining.
This, and some other discussions which have of late engaged us, were
in part intended as preparatory to the inquiry on which we entered in
the close of my Lecture,--the inquiry into the justness of the praise
which has been claimed and received by Dr Reid, as the confuter of a
very absurd theory of perception, till then universally prevalent:--and
if, indeed, the theory, which he is said to have confuted, had been the
general belief of philosophers till confuted by him, there can be no
question, that he would have had a just claim to be considered as one
of the chief benefactors of the Philosophy of Mind. At any rate, since
this glory has been ascribed to him, and his supposed confutation of
the theory of perception, by little images of objects conveyed to the
mind, has been considered as forming one of the most important eras
in intellectual science, it has acquired, from this universality of
mistake with respect to it, an interest which, from its own merits, it
would certainly be far from possessing.
In the Philosophy of the Peripatetics, and in all the dark ages of the
scholastic followers of that system, _ideas_ were truly considered as
little images derived from objects without; and, as the word _idea_
still continued to be used after this original meaning had been
abandoned, (as it continues still, in all the works that treat of
perception,) it is not wonderful that many of the accustomed forms of
expression, which were retained together with it, should have been of
a kind that, in their strict etymological meaning, might have seemed
to harmonize more with the theory of ideas as images, which prevailed
when these particular forms of expression originally became habitual,
than with that of _ideas_ as mere _states of the mind itself_; since
this is only what has happened with respect to innumerable other words,
in the transmutations of meaning which they have received during the
long progress of scientific inquiry. The idea, in the old philosophy,
had been that, of which the presence immediately preceded the mental
perception,--the direct external cause of perception; and accordingly,
it may well be supposed, that when the direct cause of perception was
believed to be, not a foreign phantasm, but a peculiar affection of
the sensorial organ, that word, which had formerly been applied to
the supposed object, would still imply some reference to the organic
state, which was believed to supply the place of the shadowy film, or
phantasm, in being, what it had been supposed to be, the immediate
antecedent of perception. Idea, in short, in the old writers, like the
synonymous word perception at present, was expressive, not of one part
of a process, but of two parts of it. It included, with a certain vague
comprehensiveness, the _organic_ change as well as the _mental_,--in
the same way as perception now implies a certain change produced in
our organs of sense, and a consequent change in the state of the
mind; and hence it is surely not very astonishing, that while many
expressions are found in the works of these older writers, which, in
treating of ideas, have a reference to the mental part of the process
of perception, other expressions are occasionally employed which relate
only to the material part of the process,--since both parts of the
process, as I have said, were, to a certain degree, denoted by that
single word. All this might very naturally take place, though nothing
more was meant to be expressed by it than these two parts of the
process,--the organic change, whatever it might be, and the subsequent
mental change, without the necessary intervention of something distinct
from both, such as Dr Reid supposes to have been meant by the term
Idea.
It is this application, to the bodily part of the process, of
expressions, which he considered as intended to be applied to the
mental part of perception, that has sometimes misled him in the views
which he has given of the opinions of former philosophers. But still
more frequently has he been misled, by understanding in a literal
sense phrases which were intended in a metaphorical sense, and which
seem so obviously metaphorical, that it is truly difficult to account
for the misapprehension. Indeed, the same metaphors, on the mere
use of which Dr Reid founds so much, continue still to be used in
the same manner as before he wrote. We speak of impressions on the
mind,--of ideas bright or obscure, permanent or fading,--of senses,
that are the inlets to our knowledge of external things,--and of
memory, in which this knowledge is stored,--precisely as the writers
and speakers before us used these phrases; without meaning any thing
more, than that certain organic changes, necessary to perception, are
produced by external objects,--and that certain feelings, similar to
those originally excited in this manner, are afterwards renewed, with
more or less permanence and vivacity, without the recurrence of the
objects that originally produced them;--and to arrange all the moods
and figures of logic in confutation of mere metaphors, such as I
cannot but think the images in the mind to have been, which Dr Reid so
powerfully assailed, seems an undertaking not very different from that
of exposing, syllogistically and seriously, all the follies of Grecian
Paganism as a system of theological belief, in the hope of converting
some unfortunate poetaster or poet, who still talks, in his rhymings to
his mistress, of _Cupid_ and the _Graces_.
There is, however, one very important practical inference to be drawn
from this misapprehension,--the necessity of avoiding, as much as
possible, in philosophic disquisition, the language of _metaphor_,
especially when the precise meaning has not before been pointed out, so
as to render any misconception of the intended meaning, when a metaphor
is used, as nearly impossible as the condition of our intellectual
nature will allow. In calculating the possibility of this future
misconception, we should never estimate our own perspicuity very
highly; for there is always in man a redundant facility of mistake,
beyond our most liberal allowance. As Pope truly says,--
“The difference is as great between
The optics seeing, as the objects seen;”
and, unfortunately, it is the object only which is in our power. The
fallible optics, that are to view it, are beyond our controul; and
whatever opinion, therefore, the most cautious philosopher may assert,
he ought never to flatter himself with the absolute certainty, that, in
the course of a few years, he may not be exhibited, and confuted, as
the assertor of a doctrine, not merely different from that which he has
professed, but exactly opposite to it.
The true nature of the opinions really held by philosophers is,
however, to be determined by reference to their works. To this then let
us proceed.