EVERY one will readily allow, that there is a consider-
able difference between the perceptions of the mind,
when a man feels the pain of excessive heat, or the
pleasure of moderate warmth, and when he afterwards re-
calls to his memory this sensation, or anticipates it by his
imagination. These faculties may mimic or copy the percep-
tions of the senses; but they never can entirely reach the
force and vivacity of the original sentiment. The utmost we
say of them, even when they operate with greatest vigour, is,
that they represent their object in so lively a manner, that we
could almost say we feel or see it: But, except the mind be
disordered by disease or madness, they never can arrive
at such a pitch of vivacity, as to render these perceptions
altogether undistinguishable. All the colours of poetry,
however splendid, can never paint natural objects in such
a manner as to make the description be taken for a real
landskip. The most lively thought is still inferior to the
dullest sensation.
We may observe a like distinction to run through all the
other perceptions of the mind. A man in a fit of anger, is
actuated in a very different manner from one who only
thinks of that emotion. If you tell me, that any person
is in love, I easily understand your meaning, and from
a just conception of his situation; but never can mistake
that conception for the real disorders and agitations of the
passion. When we reflect on our past sentiments and
affections, our thought is a faithful mirror, and copies its
objects truly; but the colours which it employs are faint
and dull, in comparison of those in which our original per-
ceptions were clothed. It requires no nice discernment or
metaphysical head to mark the distinction between them.
Here therefore we may divide all the perceptions of the
mind into two classes or species, which are distinguished
by their different degrees of force and vivacity. The less
forcible and lively are commonly denominated Thoughts or
Ideas. The other species want a name in our language,
and in most others; I suppose, because it was not requisite
for any, but philosophical purposes, to rank them under
a general term or appellation. Let us, therefore, use a little
freedom, and call them Impressions; employing that word
in a sense somewhat different from the usual. By the term
impression, then, I mean all our more lively perceptions,
when we hear, or see, or feel, or love, or hate, or desire,
or will. And impressions are distinguished from ideas,
which are the less lively perceptions, of which we are
conscious, when we reflect on any of those sensations or
movements above mentioned.
Nothing, at first view, may seem more unbounded than
the thought of man, which not only escapes all human
power and authority, but is not even restrained within the
limits of nature and reality. To form monsters, and join
incongruous shapes and appearances, costs the imagination
no more trouble than to conceive the most natural and
familiar objects. And while the body is confined to one
planet, along which it creeps with pain and difficulty; the
thought can in an instant transport us into the most dis-
tant regions of the universe; or even beyond the universe,
into the unbounded chaos, where nature is supposed to
lie in total confusion. What never was seen, or heard
of, may yet be conceived; nor is any thing beyond
the power of thought, except what implies an absolute
contradiction.
But though our thought seems to possess this unbounded
liberty, we shall find, upon a nearer examination, that it is
really confined within very narrow limits, and that all this
creative power of the mind amounts to no more than
the faculty of compounding, transposing, augmenting, or
diminishing the materials afforded us by the senses and
experience. When we think of a golden mountain, we
only join two consistent ideas, gold, and mountain, with
which we were formerly acquainted. A virtuous horse we
can conceive; because, from our own feeling, we can
conceive virtue; and this we may unite to the figure and
shape of a horse, which is an animal familiar to us. In
short, all the materials of thinking are derived either from
our outward or inward sentiment: the mixture and com-
position of these belongs alone to the mind and will. Or,
to express myself in philosophical language, all our ideas or
more feeble perceptions are copies of our impressions or
more lively ones.
To prove this, the two following arguments will, I hope,
be sufficient. First, when we analyze our thoughts or ideas,
however compounded or sublime, we always find that they
resolve themselves into such simple ideas as were copied
from a precedent feeling or sentiment. Even those ideas,
which, at first view, seem the most wide of this origin, are
found, upon a nearer scrutiny, to be derived from it. The
idea of God, as meaning an infinitely intelligent, wise, and
good Being, arises from reflecting on the operations of our
own mind, and augmenting, without limit, those qualities
of goodness and wisdom. We may prosecute this enquiry
to what length we please; where we shall always find, that
every idea which we examine is copied from a similar
impression. Those who would assert that this position is
not universally true nor without exception, have only one,
and that an easy method of refuting it; by producing that
idea, which, in their opinion, is not derived from this source.
It will then be incumbent on us, if we would maintain our
doctrine, to produce the impression, or lively perception,
which corresponds to it.
Secondly. If it happen, from a defect of the organ,
that a man is not susceptible of any species of sensation,
we always find that he is as little susceptible of the cor-
respondent ideas. A blind man can form no notion of
colours; a deaf man of sounds. Restore either of them
that sense in which he is deficient; by opening this new
inlet for his sensations, you also open an inlet for the ideas;
and he finds no difficulty in conceiving these objects. The
case is the same, if the object, proper for exciting any
sensation, has never been applied to the organ. A Lap-
lander or Negro has no notion of the relish of wine.
And though there are few or no instances of a like
deficiency in the mind, where a person has never felt or
is wholly incapable of a sentiment or passion that belongs
to his species; yet we find the same observation to take
place in a less degree. A man of mild manners can form
no idea of inveterate revenge or cruelty; nor can a selfish
heart easily conceive the heights of friendship and gener-
osity. It is readily allowed, that other beings may possess
many senses of which we can have no conception; because
the ideas of them have never been introduced to us in the
only manner by which an idea can have access to the mind,
to wit, by the actual feeling and sensation.
There is, however, one contradictory phenomenon, which
may prove that it is not absolutely impossible for ideas
to arise, independent of their correspondent impressions.
I believe it will readily be allowed, that the several distinct
ideas of colour, which enter by the eye, or those of sound,
which are conveyed by the ear, are really different from
each other; though, at the same time, resembling. Now
if this be true of different colours, it must be no less so of
the different shades of the same colour; and each shade
produces a distinct idea, independent of the rest. For if
this should be denied, it is possible, by the continual grada-
tion of shades, to run a colour insensibly into what is most
remote from it; and if you will not allow any of the means
to be different, you cannot, without absurdity, deny the
extremes to be the same. Suppose, therefore, a person
to have enjoyed his sight for thirty years, and to have
become perfectly acquainted with colours of all kinds
except one particular shade of blue, for instance, which it
never has been his fortune to meet with. Let all the
different shades of that colour, except that single one, be
placed before him, descending gradually from the deepest
to the lightest; it is plain that he will perceive a blank,
where that shade is wanting, and will be sensible that there
is a greater distance in that place between the contiguous
colour than in any other. Now I ask, whether it be
possible for him, from his own imagination, to supply this
deficiency, and raise up to himself the idea of that particular
shade, though it had never been conveyed to him by his
senses? I believe there are few but will be of opinion
that he can: and this may serve as a proof that the simple
ideas are not always, in every instance, derived from the
correspondent impressions; though this instance is so
singular, that it is scarcely worth our observing, and does
not merit that for it alone we should alter our general
maxim.
Here, therefore, is a proposition, which not only seems,
in itself, simple and intelligible; but, if a proper use were
made of it, might render every dispute equally intelligible,
and banish all that jargon, which has so long taken
possession of metaphysical reasonings, and drawn disgrace
upon them. All ideas, especially abstract ones, are naturally
faint and obscure: the mind has but a slender hold of them:
they are apt to be confounded with other resembling ideas;
and when we have often employed any term, though with-
out a distinct meaning, we are apt to imagine it has a deter-
minate idea annexed to it. On the contrary, all impressions,
that is, all sensations, either outward or inward, are strong
and vivid: the limits between them are more exactly deter-
mined: nor is it easy to fall into any error or mistake with
regard to them. When we entertain, therefore, any suspicion
that a philosophical term is employed without any meaning
or idea (as is but too frequent), we need but enquire, from
what impression is that supposed idea derived? And if it
be impossible to assign any, this will serve to confirm our
suspicion. By bringing ideas into so clear a light we may
reasonably hope to remove all dispute, which may arise,
concerning their nature and reality.[1]
[1] It is probable that no more was meant by these, who denied innate
ideas, than that all ideas were copies of our impressions; though it must
be confessed, that the terms, which they employed, were not chosen with
such caution, nor so exactly defined, as to prevent all mistakes about their
doctrine. For what is meant by innate? If innate be equivalent to natural,
then all the perceptions and ideas of the mind must be allowed to be innate
or natural, in whatever sense we take the latter word, whether in opposi-
tion to what is uncommon, artificial, or miraculous. If by innate be meant,
contemporary to our birth, the dispute seems to be frivolous; nor is it
worth while to enquire at what time thinking begins, whether before, at,
or after our birth. Again, the word idea, seems to be commonly taken in
a very loose sense, by LOCKE and others; as standing for any of our per-
ceptions, our sensations and passions, as well as thoughts. Now in this
sense, I should desire to know, what can be meant by asserting, that self-
love, or resentment of injuries, or the passion between the sexes is not innate?
But admitting these terms, impressions and ideas, in the sense above
explained, and understanding by innate, what is original or copied from
no precedent perception, then may we assert that all our impressions are
innate, and our ideas not innate.
To be ingenuous, I must own it to be my opinion, that LOCKE was
betrayed into this question by the schoolmen, who, making use of unde-
fined terms, draw out their disputes to a tedious length, without ever touch-
ing the point in question. A like ambiguity and circumlocution seem to run
through that philosopher's reasonings on this as well as most other subjects.
SECTION III
OF THE ASSOCIATION OF IDEAS
IT IS evident that there is a principle of connexion be-
tween the different thoughts or ideas of the mind, and
that in their appearance to the memory or imagination,
they introduce each other with a certain degree of method
and regularity. In our more serious thinking or discourse
this is so observable that any particular thought, which
breaks in upon the regular tract or chain of ideas, is
immediately remarked and rejected. And even in our
wildest and most wandering reveries, nay in our very
dreams, we shall find, if we reflect, that the imagination
ran not altogether at adventures, but that there was still
a connexion upheld among the different ideas, which suc-
ceeded each other. Were the loosest and freest conversa-
tion to be transcribed, there would immediately be observed
something which connected it in all its transitions. Or
where this is wanting, the person who broke the thread of
discourse might still inform you, that there had secretly
revolved in his mind a succession of thought, which had
gradually led him from the subject of conversation. Among
different languages, even where we cannot suspect the least
connexion or communication, it is found, that the words,
expressive of ideas, the most compounded, do yet nearly
correspond to each other: a certain proof that the simple
ideas, comprehended in the compound ones, were bound
together by some universal principle, which had an equal
influence on all mankind.
Though it be too obvious to escape observation, that
different ideas are connected together; I do not find that
any philosopher has attempted to enumerate or class all
the principles of association; a subject, however, that seems
worthy of curiosity. To me, there appear to be only three
principles of connexion among ideas, namely, Resemblance,
Contiguity in time or place, and Cause or Effect.
That these principles serve to connect ideas will not, I
believe, be much doubted. A picture naturally leads our
thoughts to the original:[1] the mention of one apartment
in a building naturally introduces an enquiry or discourse
concerning the others:[2] and if we think of a wound, we
can scarcely forbear reflecting on the pain which follows it.[3]
But that this enumeration is complete, and that there are
no other principles of association except these, may be
difficult to prove to the satisfaction of the reader, or even
to a man's own satisfaction. All we can do, in such cases,
is to run over several instances, and examine carefully the
principle which binds the different thoughts to each other,
never stopping till we render the principle as general as
possible.[4] The more instances we examine, and the more
care we employ, the more assurance shall we acquire, that
the enumeration, which we form from the whole, is com-
plete and entire.
[1] Resemblance.
[2] Contiguity.
[3] Cause and effect.
[4] For instance, Contrast or Contrariety is also a connexion among Ideas:
but it may perhaps, be considered as a mixture of Causation and Resem-
blance. Where two objects are contrary, the one destroys the other; that
is, the cause of its annihilation, and the idea of the annihilation of an
object, implies the idea of its former existence.
SCEPTICAL DOUBTS CONCERNING THE OPERATIONS OF
THE UNDERSTANDING
PART I
ALL the objects of human reason or enquiry may
naturally be divided into two kinds, to wit, Rela-
tions of Ideas, and Matters of Fact. Of the first
kind are the sciences of Geometry, Algebra, and Arithmetic;
and in short, every affirmation which is either intuitively or
demonstratively certain. That the square of the hypothenuse
is equal to the square of the two sides, is a proposition
which expresses a relation between these figures. That
three times five is equal to the half of thirty, expresses a
relation between these numbers. Propositions of this kind
are discoverable by the mere operation of thought, without
dependence on what is anywhere existent in the universe.
Though there never were a circle or triangle in nature, the
truths demonstrated by Euclid would for ever retain their
certainty and evidence.
Matters of fact, which are the second objects of human
reason, are not ascertained in the same manner; nor is our
evidence of their truth, however great, of a like nature with
the foregoing. The contrary of every matter of fact is still
possible; because it can never imply a contradiction, and
is conceived by the mind with the same facility and dis-
tinctness, as if ever so conformable to reality. That the
sun will not rise to-morrow is no less intelligible a propo-
sition, and implies no more contradiction than the affirma-
tion, that it will rise. We should in vain, therefore, attempt
to demonstrate its falsehood. Were it demonstratively false,
it would imply a contradiction, and could never be dis-
tinctly conceived by the mind.
It may, therefore, be a subject worthy of curiosity, to
enquire what is the nature of that evidence which assures
us of any real existence and matter of fact, beyond the
present testimony of our senses, or the records of our
memory. This part of philosophy, it is observable, has been
little cultivated, either by the ancients or moderns; and
therefore our doubts and errors, in the prosecution of so
important an enquiry, may be the more excusable; while
we march through such difficult paths without any guide
or direction. They may even prove useful, by exciting
curiosity, and destroying that implicit faith and security,
which is the bane of all reasoning and free enquiry. The
discovery of defects in the common philosophy, if any such
there be, will not, I presume, be a discouragement, but
rather an incitement, as is usual, to attempt something
more full and satisfactory than has yet been proposed to
the public.
All reasonings concerning matter of fact seem to be
founded on the relation of Cause and Effect. By means of
that relation alone we can go beyond the evidence of our
memory and senses. If you were to ask a man, why he
believes any matter of fact, which is absent; for instance,
that his friend is in the country, or in France; he would
give you a reason; and this reason would be some other
fact; as a letter received from him, or the knowledge of his
former resolutions and promises. A man finding a watch
or any other machine in a desert island, would conclude
that there had once been men in that island. All our rea-
sonings concerning fact are of the same nature. And here
it is constantly supposed that there is a connexion between
the present fact and that which is inferred from it. Were
there nothing to bind them together, the inference would
be entirely precarious. The hearing of an articulate voice
and rational discourse in the dark assures us of the pres-
ence of some person: Why? because these are the effects
of the human make and fabric, and closely connected with
it. If we anatomize all the other reasonings of this nature,
we shall find that they are founded on the relation of cause
and effect, and that this relation is either near or remote,
direct or collateral. Heat and light are collateral effects
of fire, and the one effect may justly be inferred from the
other.
If we would satisfy ourselves, therefore, concerning the
nature of that evidence, which assures us of matters of fact,
we must enquire how we arrive at the knowledge of cause
and effect.
I shall venture to affirm, as a general proposition, which
admits of no exception, that the knowledge of this relation
is not, in any instance, attained by reasonings a priori; but
arises entirely from experience, when we find that any
particular objects are constantly conjoined with each other.
Let an object be presented to a man of ever so strong natural
reason and abilities; if that object be entirely new to him,
he will not be able, by the most accurate examination of
its sensible qualities, to discover any of its causes or effects.
Adam, though his rational faculties be supposed, at the
very first, entirely perfect, could not have inferred from
the fluidity and transparency of water that it would suffo-
cate him, or from the light and warmth of fire that it would
consume him. No object ever discovers, by the qualities
which appear to the senses, either the causes which pro-
duced it, or the effects which will arise from it; nor can
our reason, unassisted by experience, ever draw any in-
ference concerning real existence and matter of fact.
This proposition, that causes and effects are discoverable,
not by reason but by experience, will readily be admitted
with regard to such objects, as we remember to have once
been altogether unknown to us; since we must be conscious
of the utter inability, which we then lay under, of foretelling
what would arise from them. Present two smooth pieces of
marble to a man who has no tincture of natural philosophy;
he will never discover that they will adhere together in such
a manner as to require great force to separate them in a
direct line, while they make so small a resistance to a
lateral pressure. Such events, as bear little analogy to
the common course of nature, are also readily confessed to
be known only by experience; nor does any man imagine
that the explosion of gunpowder, or the attraction of a load-
stone, could ever be discovered by arguments a priori. In
like manner, when an effect is supposed to depend upon an
intricate machinery or secret structure of parts, we make no
difficulty in attributing all our knowledge of it to experience.
Who will assert that he can give the ultimate reason, why
milk or bread is proper nourishment for a man, not for
a lion or a tiger?
But the same truth may not appear, at first sight, to have
the same evidence with regard to events, which have become
familiar to us from our first appearance in the world, which
bear a close analogy to the whole course of nature, and
which are supposed to depend on the simple qualities of
objects, without any secret structure of parts. We are apt
to imagine that we could discover these effects by the mere
operation of our reason, without experience. We fancy,
that were we brought on a sudden into this world, we
could at first have inferred that one Billiard-ball would
communicate motion to another upon impulse; and that we
needed not to have waited for the event, in order to pro-
nounce with certainty concerning it. Such is the influence of
custom, that, where it is strongest, it not only covers our
natural ignorance, but even conceals itself, and seems not to
take place, merely because it is found in the highest degree.
But to convince us that all the laws of nature, and all
the operations of bodies without exception, are known only
by experience, the following reflections may, perhaps, suf-
fice. Were any object presented to us, and were we
required to pronounce concerning the effect, which will
result from it, without consulting past observation; after
what manner, I beseech you, must the mind proceed in this
operation? It must invent or imagine some event, which
it ascribes to the object as its effect; and it is plain that
this invention must be entirely arbitrary. The mind can
never possibly find the effect in the supposed cause, by the
most accurate scrutiny and examination. For the effect is
totally different from the cause, and consequently can never
be discovered in it. Motion in the second Billiard-ball is a
quite distinct event from motion in the first; nor is there
anything in the one to suggest the smallest hint of the
other. A stone or piece of metal raised into the air, and
left without any support, immediately falls: but to consider
the matter a priori, is there anything we discover in this
situation which can beget the idea of a downward, rather
than an upward, or any other motion, in the stone or metal?
And as the first imagination or invention of a particular
effect, in all natural operations, is arbitrary, where we con-
sult not experience; so must we also esteem the supposed
tie or connexion between the cause and effect, which binds
them together, and renders it impossible that any other
effect could result from the operation of that cause. When
I see, for instance, a Billiard-ball moving in a straight line
towards another; even suppose motion in the second ball
should by accident be suggested to me, as the result of their
contact or impulse; may I not conceive, that a hundred dif-
ferent events might as well follow from that cause? May
not both these balls remain at absolute rest? May not the
first ball return in a straight line, or leap off from the second
in any line or direction? All these suppositions are con-
sistent and conceivable. Why then should we give the
preference to one, which is no more consistent or conceivable
than the rest? All our reasonings a priori will never be
able to show us any foundation for this preference.
In a word, then, every effect is a distinct event from its
cause. It could not, therefore, be discovered in the cause,
and the first invention or conception of it, a priori, must be
entirely arbitrary. And even after it is suggested, the con-
junction of it with the cause must appear equally arbitrary;
since there are always many other effects, which, to reason,
must seem fully as consistent and natural. In vain, there-
fore, should we pretend to determine any single event, or
infer any cause or effect, without the assistance of observa-
tion and experience.
Hence we may discover the reason why no philosopher,
who is rational and modest, has ever pretended to assign
the ultimate cause of any natural operation, or to show
distinctly the action of that power, which produces any
single effect in the universe. It is confessed, that the
utmost effort of human reason is to reduce the principles,
productive of natural phenomena, to a greater simplicity,
and to resolve the many particular effects into a few gen-
eral causes, by means of reasonings from analogy, experi-
ence, and observation. But as to the causes of these general
causes, we should in vain attempt their discovery; nor shall
we ever be able to satisfy ourselves, by any particular ex-
plication of them. These ultimate springs and principles
are totally shut up from human curiosity and enquiry. Elas-
ticity, gravity, cohesion of parts, communication of motion
by impulse; these are probably the ultimate causes and prin-
ciples which we shall ever discover in nature; and we may
esteem ourselves sufficiently happy, if, by accurate enquiry
and reasoning, we can trace up the particular phenomena
to, or near to, these general principles. The most perfect
philosophy of the natural kind only staves off our ignorance
a little longer: as perhaps the most perfect philosophy of
the moral or metaphysical kind serves only to discover larger
portions of it. Thus the observation of human blindness
and weakness is the result of all philosophy, and meets us at
every turn, in spite of our endeavours to elude or avoid it.
Nor is geometry, when taken into the assistance of natural
philosophy, ever able to remedy this defect, or lead us into
the knowledge of ultimate causes, by all that accuracy of
reasoning for which it is so justly celebrated. Every part
of mixed mathematics proceeds upon the supposition that
certain laws are established by nature in her operations;
and abstract reasonings are employed, either to assist ex-
perience in the discovery of these laws, or to determine
their influence in particular instances, where it depends
upon any precise degree of distance and quantity. Thus, it
is a law of motion, discovered by experience, that the mo-
ment or force of any body in motion is in the compound
ratio or proportion of its solid contents and its velocity;
and consequently, that a small force may remove the greatest
obstacle or raise the greatest weight, if, by any contrivance
or machinery, we can increase the velocity of that force,
so as to make it an overmatch for its antagonist. Geometry
assists us in the application of this law, by giving us the
just dimensions of all the parts and figures which can enter
into any species of machine; but still the discovery of the
law itself is owing merely to experience, and all the abstract
reasonings in the world could never lead us one step towards
the knowledge of it. When we reason a priori, and consider
merely any object or cause, as it appears to the mind, inde-
pendent of all observation, it never could suggest to us the
notion of any distinct object, such as its effect; much less,
show us the inseparable and inviolable costnnexion between
them. A man must be very sagacious who could discover
by reasoning that crystal is the effect of heat, and ice of
cold, without being previously acquainted with the operation
of these qualities
