as if divided by something visible and tangible. This invisible and
intangible distance is also found by experience to contain a capacity of
receiving body, or of becoming visible and tangible.
Here is the whole
of my system; and in no part of it have I endeavoured to explain the
cause, which separates bodies after this manner, and gives them a
capacity of receiving others betwixt them, without any impulse or
penetration.
I answer this objection, by pleading guilty, and by confessing that my
intention never was to penetrate into the nature of bodies, or explain
the secret causes of their operations. For besides that this belongs not
to my present purpose, I am afraid, that such an enterprise is beyond
the reach of human understanding, and that we can never pretend to
know body otherwise than by those external properties, which discover
themselves to the senses. As to those who attempt any thing farther, I
cannot approve of their ambition, till I see, in some one instance at
least, that they have met with success. But at present I content myself
with knowing perfectly the manner in which objects affect my senses, and
their connections with each other, as far as experience informs me of
them. This suffices for the conduct of life; and this also suffices for
my philosophy, which pretends only to explain the nature and causes of
our perceptions, or impressions and ideas [Footnote 4.].
[Footnote 4. As long as we confine our speculations to the
appearances of objects to our senses, without entering into
disquisitions concerning their real nature and operations,
we are safe from all difficulties, and can never be embarrassed by any question. Thus, if it be asked, if the
invisible and intangible distance, interposed betwixt two
objects, be something or nothing: It is easy to answer, that
it is SOMETHING, VIZ. a property of the objects, which
affect the SENSES after such a particular manner.
If it be
asked whether two objects, having such a distance betwixt
them, touch or not: it may be answered, that this depends
upon the definition of the word, TOUCH. If objects be said
to touch, when there is nothing SENSIBLE interposed betwixt
them, these objects touch: it objects be said to touch, when
their IMAGES strike contiguous parts of the eye, and when
the hand FEELS both objects successively, without any
interposed motion, these objects do not touch. The appearances of objects to our senses are all consistent; and
no difficulties can ever arise, but from the obscurity of
the terms we make use of.
If we carry our enquiry beyond the appearances of objects to
the senses, I am afraid, that most of our conclusions will
be full of scepticism and uncertainty. Thus if it be asked,
whether or not the invisible and intangible distance be
always full of body, or of something that by an improvement
of our organs might become visible or tangible, I must
acknowledge, that I find no very decisive arguments on
either side; though I am inclined to the contrary opinion,
as being more suitable to vulgar and popular notions. If THE
NEWTONIAN philosophy be rightly understood, it will be found
to mean no more. A vacuum is asserted: That is, bodies are
said to be placed after such a manner, is to receive bodies
betwixt them, without impulsion or penetration. The real
nature of this position of bodies is unknown. We are only
acquainted with its effects on the senses, and its power of
receiving body. Nothing is more suitable to that philosophy,
than a modest scepticism to a certain degree, and a fair
confession of ignorance in subjects, that exceed all human
capacity.]
I shall conclude this subject of extension with a paradox, which will
easily be explained from the foregoing reasoning. This paradox is, that
if you are pleased to give to the in-visible and intangible distance,
or in other words, to the capacity of becoming a visible and tangible
distance, the name of a vacuum, extension and matter are the same, and
yet there is a vacuum. If you will not give it that name, motion
is possible in a plenum, without any impulse in infinitum, without
returning in a circle, and without penetration. But however we may
express ourselves, we must always confess, that we have no idea of any
real extension without filling it with sensible objects, and conceiving
its parts as visible or tangible.
As to the doctrine, that time is nothing but the manner, in which
some real objects exist; we may observe, that it is liable to the same
objections as the similar doctrine with regard to extension. If it be a
sufficient proof, that we have the idea of a vacuum, because we dispute
and reason concerning it; we must for the same reason have the idea
of time without any changeable existence; since there is no subject of
dispute more frequent and common. But that we really have no such idea,
is certain. For whence should it be derived? Does it arise from an
impression of sensation or of reflection? Point it out distinctly to us,
that we may know its nature and qualities. But if you cannot point
out any such impression, you may be certain you are mistaken, when you
imagine you have any such idea.
But though it be impossible to shew the impression, from which the idea
of time without a changeable existence is derived; yet we can easily
point out those appearances, which make us fancy we have that idea. For
we may observe, that there is a continual succession of perceptions in
our mind; so that the idea of time being for ever present with us; when
we consider a stedfast object at five-a-clock, and regard the same at
six; we are apt to apply to it that idea in the same manner as if every
moment were distinguished by a different position, or an alteration
of the object. The first and second appearances of the object, being
compared with the succession of our perceptions, seem equally removed as
if the object had really changed. To which we may add, what experience
shews us, that the object was susceptible of such a number of changes
betwixt these appearances; as also that the unchangeable or rather
fictitious duration has the same effect upon every quality, by
encreasing or diminishing it, as that succession, which is obvious to
the senses. From these three relations we are apt to confound our ideas,
and imagine we can form the idea of a time and duration, without any
change or succession.
SECT. VI. OF THE IDEA OF EXISTENCE, AND OF EXTERNAL
EXISTENCE.
It may not be amiss, before we leave this subject, to explain the ideas
of existence and of external existence; which have their difficulties,
as well as the ideas of space and time. By this means we shall be the
better prepared for the examination of knowledge and probability, when
we understand perfectly all those particular ideas, which may enter into
our reasoning.
There is no impression nor idea of any kind, of which we have any
consciousness or memory, that is not conceived as existent; and it
is evident, that from this consciousness the most perfect idea and
assurance of being is derived. From hence we may form a dilemma, the
most clear and conclusive that can be imagined, viz.
that since we never
remember any idea or impression without attributing existence to it,
the idea of existence must either be derived from a distinct impression,
conjoined with every perception or object of our thought, or must be the
very same with the idea of the perception or object.
As this dilemma is an evident consequence of the principle, that every
idea arises from a similar impression, so our decision betwixt the
propositions of the dilemma is no more doubtful. So far from there being
any distinct impression, attending every impression and every idea,
that I do not think there are any two distinct impressions, which are
inseparably conjoined. Though certain sensations may at one time be
united, we quickly find they admit of a separation, and may be presented
apart. And thus, though every impression and idea we remember be
considered as existent, the idea of existence is not derived from any
particular impression.
The idea of existence, then, is the very same with the idea of what we
conceive to be existent. To reflect on any thing simply, and to reflect
on it as existent, are nothing different from each other. That idea,
when conjoined with the idea of any object, makes no addition to it.
Whatever we conceive, we conceive to be existent. Any idea we please
to form is the idea of a being; and the idea of a being is any idea we
please to form.
Whoever opposes this, must necessarily point out that distinct
impression, from which the idea of entity is derived, and must prove,
that this impression is inseparable from every perception we believe to
be existent. This we may without hesitation conclude to be impossible.
Our foregoing reasoning [Part I. Sect. 7.] concerning the distinction of
ideas without any real difference will not here serve us in any stead.
That kind of distinction is founded on the different resemblances, which
the same simple idea may have to several different ideas. But no object
can be presented resembling some object with respect to its existence,
and different from others in the same particular; since every object,
that is presented, must necessarily be existent.
A like reasoning will account for the idea of external existence. We may
observe, that it is universally allowed by philosophers, and is besides
pretty obvious of itself, that nothing is ever really present with the
mind but its perceptions or impressions and ideas, and that external
objects become known to us only by those perceptions they occasion. To
hate, to love, to think, to feel, to see; all this is nothing but to
perceive.
Now since nothing is ever present to the mind but perceptions, and since
all ideas are derived from something antecedently present to the mind;
it follows, that it is impossible for us so much as to conceive or form
an idea of any thing specifically different from ideas and impressions.
Let us fix our attention out of ourselves as much as possible: Let us
chase our imagination to the heavens, or to the utmost limits of the
universe; we never really advance a step beyond ourselves, nor can
conceive any kind of existence, but those perceptions, which
have appeared in that narrow compass. This is the universe of the
imagination, nor have we any idea but what is there produced.
The farthest we can go towards a conception of external objects, when
supposed SPECIFICALLY different from our perceptions, is to form a
relative idea of them, without pretending to comprehend the related
objects. Generally speaking we do not suppose them specifically
different; but only attribute to them different relations, connections
and durations. But of this more fully hereafter.[Part IV, Sect. 2.]
PART III. OF KNOWLEDGE AND PROBABILITY.
SECT. I. OF KNOWLEDGE.
There are seven [Part I. Sect. 5.] different kinds of philosophical
relation, viz. RESEMBLANCE, IDENTITY, RELATIONS OF TIME
AND PLACE,
PROPORTION IN QUANTITY OR NUMBER, DEGREES IN ANY
QUALITY, CONTRARIETY
and CAUSATION. These relations may be divided into two classes; into
such as depend entirely on the ideas, which we compare together, and
such as may be changed without any change in the ideas.
It is from the
idea of a triangle, that we discover the relation of equality, which its
three angles bear to two right ones; and this relation is invariable,
as long as our idea remains the same. On the contrary, the relations of
contiguity and distance betwixt two objects may be changed merely by an
alteration of their place, without any change on the objects themselves
or on their ideas; and the place depends on a hundred different
accidents, which cannot be foreseen by the mind. It is the same case
with identity and causation. Two objects, though perfectly resembling
each other, and even appearing in the same place at different times, may
be numerically different: And as the power, by which one object produces
another, is never discoverable merely from their idea, it is evident
cause and effect are relations, of which we receive information from
experience, and not from any abstract reasoning or reflection. There is
no single phaenomenon, even the most simple, which can be accounted for
from the qualities of the objects, as they appear to us; or which we
coued foresee without the help of our memory and experience.
It appears, therefore, that of these seven philosophical relations,
there remain only four, which depending solely upon ideas, can be
the objects of knowledge and certainty. These four are RESEMBLANCE,
CONTRARIETY, DEGREES IN QUALITY, and PROPORTIONS IN
QUANTITY OR NUMBER.
Three of these relations are discoverable at first sight, and fall more
properly under the province of intuition than demonstration. When any
objects resemble each other, the resemblance will at first strike the
eye, or rather the mind; and seldom requires a second examination. The
case is the same with contrariety, and with the degrees of any quality.
No one can once doubt but existence and non-existence destroy each
other, and are perfectly incompatible and contrary. And though it be
impossible to judge exactly of the degrees of any quality, such as
colour, taste, heat, cold, when the difference betwixt them is very
small: yet it is easy to decide, that any of them is superior or
inferior to another, when their difference is considerable. And this
decision we always pronounce at first sight, without any enquiry or
reasoning.
We might proceed, after the same manner, in fixing the proportions
of quantity or number, and might at one view observe a superiority
or inferiority betwixt any numbers, or figures; especially where the
difference is very great and remarkable. As to equality or any exact
proportion, we can only guess at it from a single consideration; except
in very short numbers, or very limited portions of extension; which are
comprehended in an instant, and where we perceive an impossibility of
falling into any considerable error. In all other cases we must settle
the proportions with some liberty, or proceed in a more artificial
manner.
I have already observed, that geometry, or the art, by which we fix
the proportions of figures; though it much excels both in universality
and exactness, the loose judgments of the senses and imagination; yet
never attains a perfect precision and exactness. It's first principles
are still drawn from the general appearance of the objects; and that
appearance can never afford us any security, when we examine, the
prodigious minuteness of which nature is susceptible.
Our ideas seem
to give a perfect assurance, that no two right lines can have a common
segment; but if we consider these ideas, we shall find, that they always
suppose a sensible inclination of the two lines, and that where the
angle they form is extremely small, we have no standard of a I @ right
line so precise as to assure us of the truth of this proposition. It is
the same case with most of the primary decisions of the mathematics.
There remain, therefore, algebra and arithmetic as the only sciences, in
which we can carry on a chain of reasoning to any degree of intricacy,
and yet preserve a perfect exactness and certainty. We are possest of a
precise standard, by which we can judge of the equality and proportion
of numbers; and according as they correspond or not to that standard,
we determine their relations, without any possibility of error. When two
numbers are so combined, as that the one has always an unite answering
to every unite of the other, we pronounce them equal; and it is for want
of such a standard of equality in extension, that geometry can scarce be
esteemed a perfect and infallible science.
But here it may not be amiss to obviate a difficulty, which may arise
from my asserting, that though geometry falls short of that perfect
precision and certainty, which are peculiar to arithmetic and algebra,
yet it excels the imperfect judgments of our senses and imagination. The
reason why I impute any defect to geometry, is, because its original and
fundamental principles are derived merely from appearances; and it may
perhaps be imagined, that this defect must always attend it, and keep it
from ever reaching a greater exactness in the comparison of objects or
ideas, than what our eye or imagination alone is able to attain. I own
that this defect so far attends it, as to keep it from ever aspiring to
a full certainty: But since these fundamental principles depend on
the easiest and least deceitful appearances, they bestow on their
consequences a degree of exactness, of which these consequences are
singly incapable. It is impossible for the eye to determine the angles
of a chiliagon to be equal to 1996 right angles, or make any conjecture,
that approaches this proportion; but when it determines, that right
lines cannot concur; that we cannot draw more than one right line
between two given points; it's mistakes can never be of any consequence.
And this is the nature and use of geometry, to run us up to such
appearances, as, by reason of their simplicity, cannot lead us into any
considerable error.
I shall here take occasion to propose a second observation concerning
our demonstrative reasonings, which is suggested by the same subject of
the mathematics. It is usual with mathematicians, to pretend, that
those ideas, which are their objects, are of so refined and spiritual a
nature, that they fall not under the conception of the fancy, but must
be comprehended by a pure and intellectual view, of which the superior
faculties of the soul are alone capable. The same notion runs through
most parts of philosophy, and is principally made use of to explain oar
abstract ideas, and to shew how we can form an idea of a triangle,
for instance, which shall neither be an isoceles nor scalenum, nor be
confined to any particular length and proportion of sides. It is easy to
see, why philosophers are so fond of this notion of some spiritual
and refined perceptions; since by that means they cover many of their
absurdities, and may refuse to submit to the decisions of clear ideas,
by appealing to such as are obscure and uncertain. But to destroy this
artifice, we need but reflect on that principle so oft insisted on, that
all our ideas are copyed from our impressions. For from thence we may
immediately conclude, that since all impressions are clear and precise,
the ideas, which are copyed from them, must be of the same nature, and
can never, but from our fault, contain any thing so dark and intricate.
An idea is by its very nature weaker and fainter than an impression;
but being in every other respect the same, cannot imply any very great
mystery. If its weakness render it obscure, it is our business to
remedy that defect, as much as possible, by keeping the idea steady and
precise; and till we have done so, it is in vain to pretend to reasoning
and philosophy.
SECT. II. OF PROBABILITY, AND OF THE IDEA OF CAUSE AND
EFFECT.
This is all I think necessary to observe concerning those four
relations, which are the foundation of science; but as to the other
three, which depend not upon the idea, and may be absent or present
even while that remains the same, it will be proper to explain them more
particularly. These three relations are identity, the situations in time
and place, and causation.
All kinds of reasoning consist in nothing but a comparison, and a
discovery of those relations, either constant or inconstant, which two
or more objects bear to each other. This comparison we may make, either
when both the objects are present to the senses, or when neither of them
is present, or when only one. When both the objects are present to the
senses along with the relation, we call this perception rather than
reasoning; nor is there in this case any exercise of the thought, or
any action, properly speaking, but a mere passive admission of the
impressions through the organs of sensation. According to this way of
thinking, we ought not to receive as reasoning any of the observations
we may make concerning identity, and the relations of time and place;
since in none of them the mind can go beyond what is immediately present
to the senses, either to discover the real existence or the relations
of objects. It is only causation, which produces such a connexion, as
to give us assurance from the existence or action of one object, that it
was followed or preceded by any other existence or action; nor can the
other two relations be ever made use of in reasoning, except so far
as they either affect or are affected by it. There is nothing in any
objects to perswade us, that they are either always remote or always
contiguous; and when from experience and observation we discover, that
their relation in this particular is invariable, we, always conclude
there is some secret cause, which separates or unites them. The same
reasoning extends to identity. We readily suppose an object may continue
individually the same, though several times absent from and present
to the senses; and ascribe to it an identity, notwithstanding the
interruption of the perception, whenever we conclude, that if we had
kept our eye or hand constantly upon it, it would have conveyed an
invariable and uninterrupted perception. But this conclusion beyond the
impressions of our senses can be founded only on the connexion of cause
and effect; nor can we otherwise have any security, that the object is
not changed upon us, however much the new object may resemble that which
was formerly present to the senses. Whenever we discover such a perfect
resemblance, we consider, whether it be common in that species of
objects; whether possibly or probably any cause coued operate in
producing the change and resemblance; and according as we determine
concerning these causes and effects, we form our judgment concerning the
identity of the object.
Here then it appears, that of those three relations, which depend not
upon the mere ideas, the only one, that can be traced beyond our senses
and informs us of existences and objects, which we do not see or feel,
is causation. This relation, therefore, we shall endeavour to explain
fully before we leave the subject of the understanding.
To begin regularly, we must consider the idea of causation, and see from
what origin it is derived. It is impossible to reason justly, without
understanding perfectly the idea concerning which we reason; and it is
impossible perfectly to understand any idea, without tracing it up to
its origin, and examining that primary impression, from w