APPROACH OF TWO BODIES, WHEN THEY ARE MOVED ONE TOWARDS ANOTHER, I
CALL
SOLIDITY. I wil not dispute whether this acceptation of the word solid
be nearer to its original signification than that which mathematicians
use it in. It suffices that I think the common notion of solidity will
al ow, if not justify, this use of it; but if any one think it better to
call it IMPENETRABILITY, he has my consent. Only I have thought the term
solidity the more proper to express this idea, not only because of its
vulgar use in that sense, but also because it carries something more of
positive in it than impenetrability; which is negative, and is perhaps
more a consequence of solidity, than solidity itself. This, of all
other, seems the idea most intimately connected with, and essential to
body; so as nowhere else to be found or imagined, but only in matter.
And though our senses take no notice of it, but in masses of matter, of
a bulk sufficient to cause a sensation in us: yet the mind, having once
got this idea from such grosser sensible bodies, traces it further, and
considers it, as well as figure, in the minutest particle of matter
that can exist; and finds it inseparably inherent in body, wherever or
however modified.
2. Solidity fils Space.
This is the idea which belongs to body, whereby we conceive it to fil
space. The idea of which filling of space is,--that where we imagine any
space taken up by a solid substance, we conceive it so to possess it,
that it excludes al other solid substances; and wil for ever hinder
any other two bodies, that move towards one another in a straight line,
from coming to touch one another, unless it removes from between them
in a line not parallel to that which they move in. This idea of it,
the bodies which we ordinarily handle sufficiently furnish us with.
3. Distinct from Space.
This resistance, whereby it keeps other bodies out of the space which it
possesses, is so great, that no force, how great soever, can surmount
it. All the bodies in the world, pressing a drop of water on all sides,
will never be able to overcome the resistance which it wil make, soft
as it is, to their approaching one another, til it be removed out of
their way: whereby our idea of solidity is distinguished both from pure
space, which is capable neither of resistance nor motion; and from
the ordinary idea of hardness. For a man may conceive two bodies at
a distance, so as they may approach one another, without touching
or displacing any solid thing, till their superficies come to meet;
whereby, I think, we have the clear idea of space without solidity. For
(not to go so far as annihilation of any particular body) I ask, whether
a man cannot have the idea of the motion of one single body alone,
without any other succeeding immediately into its place? I think it is
evident he can: the idea of motion in one body no more including the
idea of motion in another, than the idea of a square figure in one body
includes the idea of a square figure in another. I do not ask, whether
bodies do so EXIST, that the motion of one body cannot really be without
the motion of another. To determine this either way, is to beg the
question for or against a VACUUM. But my question is,--whether one
cannot have the IDEA of one body moved, whilst others are at rest? And I
think this no one will deny. If so, then the place it deserted gives us
the idea of pure space without solidity; whereinto any other body may
enter, without either resistance or protrusion of anything. When the
sucker in a pump is drawn, the space it fil ed in the tube is certainly
the same whether any other body follows the motion of the sucker or not:
nor does it imply a contradiction that, upon the motion of one body,
another that is only contiguous to it should not follow it. The
necessity of such a motion is built only on the supposition that the
world is full; but not on the distinct IDEAS of space and solidity,
which are as different as resistance and not resistance, protrusion and
not protrusion. And that men have ideas of space without a body, their
very disputes about a vacuum plainly demonstrate, as is shown in another
place.
4. From Hardness.
Solidity is hereby also differenced from hardness, in that solidity
consists in repletion, and so an utter exclusion of other bodies out of
the space it possesses: but hardness, in a firm cohesion of the parts of
matter, making up masses of a sensible bulk, so that the whole does not
easily change its figure. And indeed, hard and soft are names that we
give to things only in relation to the constitutions of our own bodies;
that being generally called hard by us, which wil put us to pain sooner
than change figure by the pressure of any part of our bodies; and that,
on the contrary, soft, which changes the situation of its parts upon an
easy and unpainful touch.
But this difficulty of changing the situation of the sensible parts
amongst themselves, or of the figure of the whole, gives no more
solidity to the hardest body in the world than to the softest; nor is an
adamant one jot more solid than water. For, though the two flat sides of
two pieces of marble will more easily approach each other, between which
there is nothing but water or air, than if there be a diamond between
them; yet it is not that the parts of the diamond are more solid than
those of water, or resist more; but because the parts of water, being
more easily separable from each other, they will, by a side motion, be
more easily removed, and give way to the approach of the two pieces of
marble. But if they could be kept from making place by that side motion,
they would eternally hinder the approach of these two pieces of marble,
as much as the diamond; and it would be as impossible by any force to
surmount their resistance, as to surmount the resistance of the parts of
a diamond. The softest body in the world will as invincibly resist the
coming together of any other two bodies, if it be not put out of the
way, but remain between them, as the hardest that can be found or
imagined. He that shall fill a yielding soft body well with air or
water, wil quickly find its resistance. And he that thinks that nothing
but bodies that are hard can keep his hands from approaching one
another, may be pleased to make a trial, with the air inclosed in a
football. The experiment, I have been told, was made at Florence, with
a hollow globe of gold filled with water, and exactly closed; which
further shows the solidity of so soft a body as water. For the golden
globe thus filled, being put into a press, which was driven by the
extreme force of screws, the water made itself way through the pores of
that very close metal, and finding no room for a nearer approach of its
particles within, got to the outside, where it rose like a dew, and so
fell in drops, before the sides of the globe could be made to yield to
the violent compression of the engine that squeezed it.
5. On Solidity depend Impulse, Resistance and Protrusion.
By this idea of solidity is the extension of body distinguished from
the extension of space:--the extension of body being nothing but the
cohesion or continuity of solid, separable, movable parts; and the
extension of space, the continuity of unsolid, inseparable, and
immovable parts. Upon the solidity of bodies also depend their mutual
impulse, resistance, and protrusion. Of pure space then, and solidity,
there are several (amongst which I confess myself one) who persuade
themselves they have clear and distinct ideas; and that they can think
on space, without anything in it that resists or is protruded by body.
This is the idea of pure space, which they think they have as clear
as any idea they can have of the extension of body: the idea of the
distance between the opposite parts of a concave superficies being
equally as clear without as with the idea of any solid parts between:
and on the other side, they persuade themselves that they have, distinct
from that of pure space, the idea of SOMETHING THAT FILLS SPACE, that
can be protruded by the impulse of other bodies, or resist their motion.
If there be others that have not these two ideas distinct, but confound
them, and make but one of them, I know not how men, who have the same
idea under different names, or different ideas under the same name, can
in that case talk with one another; any more than a man who, not being
blind or deaf, has distinct ideas of the colour of scarlet and the sound
of a trumpet, could discourse concerning scarlet colour with the blind
man I mentioned in another place, who fancied that the idea of scarlet
was like the sound of a trumpet.
6. What Solidity is.
If any one asks me, WHAT THIS SOLIDITY IS, I send him to his senses to
inform him. Let him put a flint or a football between his hands, and
then endeavour to join them, and he will know. If he thinks this not a
sufficient explication of solidity, what it is, and wherein it consists;
I promise to tell him what it is, and wherein it consists, when he tells
me what thinking is, or wherein it consists; or explains to me what
extension or motion is, which perhaps seems much easier. The simple
ideas we have, are such as experience teaches them us; but if, beyond
that, we endeavour by words to make them clearer in the mind, we shall
succeed no better than if we went about to clear up the darkness of a
blind man's mind by talking; and to discourse into him the ideas of
light and colours. The reason of this I shall show in another place.
CHAPTER V.
OF SIMPLE IDEAS OF DIVERS SENSES.
Ideas received both by seeing and touching.
The ideas we get by more than one sense are, of SPACE or EXTENSION,
FIGURE, REST, and MOTION. For these make perceivable impressions, both
on the eyes and touch; and we can receive and convey into our minds the
ideas of the extension, figure, motion, and rest of bodies, both by
seeing and feeling. But having occasion to speak more at large of these
in another place, I here only enumerate them.
CHAPTER VI.
OF SIMPLE IDEAS OF REFLECTION.
Simple Ideas are the Operations of Mind about its other Ideas.
The mind receiving the ideas mentioned in the foregoing chapters from
without, when it turns its view inward upon itself, and observes its own
actions about those ideas it has, takes from thence other ideas, which
are as capable to be the objects of its contemplation as any of those it
received from foreign things.
The Idea of Perception, and Idea of Willing, we have from Reflection.
The two great and principal actions of the mind, which are most
frequently considered, and which are so frequent that every one that
pleases may take notice of them in himself, are these two:--
PERCEPTION, or THINKING; and VOLITION, or WILLING.
The power of thinking is caled the UNDERSTANDING, and the power of
volition is cal ed the WILL; and these two powers or abilities in the
mind are denominated faculties.
Of some of the MODES of these simple ideas of reflection, such as are
REMEMBRANCE, DISCERNING, REASONING, JUDGING, KNOWLEDGE, FAITH, &c., I
shall have occasion to speak hereafter.
CHAPTER VII.
OF SIMPLE IDEAS OF BOTH SENSATION AND REFLECTION.
1. Ideas of Pleasure and Pain.
There be other simple ideas which convey themselves into the mind by all
the ways of sensation and reflection, viz. PLEASURE or DELIGHT, and its
opposite, PAIN, or UNEASINESS; POWER; EXISTENCE; UNITY mix with almost
al our other Ideas.
2. Delight or uneasiness, one or other of them, join themselves to
almost all our ideas both of sensation and reflection: and there is
scarce any affection of our senses from without, any retired thought of
our mind within, which is not able to produce in us pleasure or pain. By
pleasure and pain, I would be understood to signify, whatsoever delights
or molests us; whether it arises from the thoughts of our minds, or
anything operating on our bodies. For, whether we call it; satisfaction,
delight, pleasure, happiness, &c., on the one side, I or uneasiness,
trouble, pain, torment, anguish, misery, &c., the other, they are still
but different degrees of the same thing, and belong to the ideas of
pleasure and pain, delight or uneasiness; which are the names I shall
most commonly use for those two sorts of ideas.
3. As motives of our actions.
The infinite wise Author of our being, having given us the power over
several parts of our bodies, to move or keep them at rest as we think
fit; and also, by the motion of them, to move ourselves and other
contiguous bodies, in which consist all the actions of our body: having
also given a power to our minds, in several instances, to choose,
amongst its ideas, which it will think on, and to pursue the inquiry of
this or that subject with consideration and attention, to excite us to
these actions of thinking and motion that we are capable of,--has been
pleased to join to several thoughts, and several sensations a perception
of delight. If this were whol y separated from al our outward
sensations, and inward thoughts, we should have no reason to prefer one
thought or action to another; negligence to attention, or motion to
rest. And so we should neither stir our bodies, nor employ our minds,
but let our thoughts (if I may so call it) run adrift, without any
direction or design, and suffer the ideas of our minds, like unregarded
shadows, to make their appearances there, as it happened, without
attending to them. In which state man, however furnished with the
faculties of understanding and will, would be a very idle, inactive
creature, and pass his time only in a lazy, lethargic dream. It has
therefore pleased our wise Creator to annex to several objects, and the
ideas which we receive from them, as also to several of our thoughts, a
concomitant pleasure, and that in several objects, to several degrees,
that those faculties which he had endowed us with might not remain
wholly idle and unemployed by us.
4. An end and use of pain.
Pain has the same efficacy and use to set us on work that pleasure has,
we being as ready to employ our faculties to avoid that, as to pursue
this: only this is worth our consideration, that pain is often produced
by the same objects and ideas that produce pleasure in us. This their
near conjunction, which makes us often feel pain in the sensations where
we expected pleasure, gives us new occasion of admiring the wisdom and
goodness of our Maker, who, designing the preservation of our being, has
annexed pain to the application of many things to our bodies, to warn us
of the harm that they wil do, and as advices to withdraw from them. But
he, not designing our preservation barely, but the preservation of every
part and organ in its perfection, hath in many cases annexed pain to
those very ideas which delight us. Thus heat, that is very agreeable to
us in one degree, by a little greater increase of it proves no ordinary
torment: and the most pleasant of al sensible objects, light itself,
if there be too much of it, if increased beyond a due proportion to our
eyes, causes a very painful sensation. Which is wisely and favourably so
ordered by nature, that when any object does, by the vehemency of its
operation, disorder the instruments of sensation, whose structures
cannot but be very nice and delicate, we might, by the pain, be warned
to withdraw, before the organ be quite put out of order, and so be
unfitted for its proper function for the future. The consideration of
those objects that produce it may wel persuade us, that this is the end
or use of pain. For, though great light be insufferable to our eyes, yet
the highest degree of darkness does not at all disease them: because
that, causing no disorderly motion in it, leaves that curious organ
unarmed in its natural state. But yet excess of cold as wel as heat
pains us: because it is equally destructive to that temper which is
necessary to the preservation of life, and the exercise of the several
functions of the body, and which consists in a moderate degree of
warmth; or, if you please, a motion of the insensible parts of our
bodies, confined within certain bounds.
5. Another end.
Beyond all this, we may find another reason why God hath scattered up
and down several degrees of pleasure and pain, in al the things that
environ and affect us; and blended them together in almost al that our
thoughts and senses have to do with;--that we, finding imperfection,
dissatisfaction, and want of complete happiness, in all the enjoyments
which the creatures can afford us, might be led to seek it in the
enjoyment of Him with whom there is fullness of joy, and at whose right
hand are pleasures for evermore.
6. Goodness of God in annexing pleasure and pain to our other ideas.
Though what I have here said may not, perhaps, make the ideas of
pleasure and pain clearer to us than our own experience does, which is
the only way that we are capable of having them; yet the consideration
of the reason why they are annexed to so many other ideas, serving to
give us due sentiments of the wisdom and goodness of the Sovereign
Disposer of all things, may not be unsuitable to the main end of these
inquiries: the knowledge and veneration of him being the chief end of
al our thoughts, and the proper business of all understandings.
7. Ideas of Existence and Unity.
EXISTENCE and UNITY are two other ideas that are suggested to the
understanding by every object without, and every idea within. When ideas
are in our minds, we consider them as being actually there, as wel
as we consider things to be actually without us;--which is, that they
exist, or have existence. And whatever we can consider as one thing,
whether a real being or idea, suggests to the understanding the idea of
unity.
8. Idea of Power.
POWER also is another of those simple ideas which we receive from
sensation and reflection. For, observing in ourselves that we do and
can think, and that we can at pleasure move several parts of our bodies
which were at rest; the effects, also, that natural bodies are able to
produce in one another, occurring every moment to our senses,--we both
these ways get the idea of power.
9. Idea of Succession.
Besides these there is another idea, which, though suggested by our
senses, yet is more constantly offered to us by what passes in our
minds; and that is the idea of SUCCESSION. For if we look immediately
into ourselves, and reflect on what is observable there, we shall find
our ideas always, whilst we are awake, or have any thought, passing in
train, one going and another coming, without intermission.
10. Simple Ideas the materials of al our Knowledge.
These, if they are not all, are at least (as I think) the most
considerable of those simple ideas which the mind has, out of which is
made all its other knowledge; al which it receives only by the two
forementioned ways of sensation and reflection.
Nor let any one think these too narrow bounds for the capacious mind of
man to expatiate in, which takes its flight further than the stars, and
cannot be confined by the limits of the world; that extends its thoughts
often even beyond the utmost expansion of Matter, and makes excursions
into that incomprehensible Inane. I grant al this, but desire any one
to assign any SIMPLE IDEA which is not received from one of those inlets
before mentioned, or any COMPLEX IDEA not made out of those simple ones.
Nor wil it be so strange to think these few simple ideas sufficient to
employ the quickest thought, or largest capacity; and to furnish the
materials of all that various knowledge, and more various fancies and
opinions of al mankind, if we consider how many words may be made out
of the various composition of twenty-four letters; or if, going one step
further, we wil but reflect on the variety of combinations that may be
made with barely one of the above-mentioned ideas, viz. number, whose
stock is inexhaustible and truly infinite: and what a large and immense
field doth extension alone afford the mathematicians?
CHAPTER VIII.
SOME FURTHER CONSIDERATIONS CONCERNING OUR SIMPLE IDEAS OF
SENSATION.
1. Positive Ideas from privative causes.
Concerning the simple ideas of Sensation; it is to be considered,--that
whatsoever is so constituted in nature as to be able, by affecting our
senses, to cause any perception in the mind, doth thereby produce in the
understanding a simple idea; which, whatever be the external cause of
it, when it comes to be taken notice of by our discerning faculty, it is
by the mind looked on and considered there to be a real positive idea in
the understanding, as much as any other whatsoever; though, perhaps, the
cause of it be but a privation of the subject.
2. Ideas in the mind distinguished from that in things which gives rise
to them.
Thus the ideas of heat and cold, light and darkness, white and black,
motion and rest, are equally clear and positive ideas in the mind;
though, perhaps, some of the causes which produce them are barely
privations, in those subjects from whence our senses derive those ideas.
These the understanding, in its view of them, considers all as distinct
positive ideas, without taking notice of the causes that produce
them: which is an inquiry not belonging to the idea, as it is in the
understanding, but to the nature of the things existing without us.
These are two very different things, and carefully to be distinguished;
it being one thing to perceive and know the idea of white or black, and
quite another to examine what kind of particles they must be, and how
ranged in the superficies, to make any object appear white or black.
3. We may have the ideas when we are ignorant of their physical causes.
A painter or dyer who never inquired into their causes hath the ideas
of white and black, and other colours, as clearly, perfectly, and
distinctly in his understanding, and perhaps more distinctly, than the
philosopher who hath busied himself in considering their natures, and
thinks he knows how far either of them is, in its cause, positive or
privative; and the idea of black is no less positive in his mind than
that of white, however the cause of that colour in the external object
may be only a privation.
4. Why a privative cause in nature may occasion a positive idea.
If it were the design of my present undertaking to inquire into the
natural causes and manner of perception, I should offer this as a reason
why a privative cause might, in some cases at least, produce a positive
idea; viz. that all sensation being produced in us only by different
degrees and modes of motion in our animal spirits, variously agitated by
external objects, the abatement of any former motion must as necessarily
produce a new sensation as the variation or increase of it; and so
introduce a new idea, which depends only on a different motion of the
animal spirits in that organ.
5. Negative names need not be meaningless.
But whether this be so or not I wil not here determine, but appeal
to every one's own experience, whether the shadow of a man, though it
consists of nothing but the absence of light (and the more the absence
of light is, the more discernible is the shadow) does not, when a man
looks on it, cause as clear and positive idea in his mind, as a man
himself, though covered over with clear sunshine? And the picture of a
shadow is a positive thing. Indeed, we have negative names, to which
there be no positive ideas; but they consist wholly in negation of some
certain ideas, as SILENCE, INVISIBLE; but these signify not any ideas in
the mind but their absence.
6. Whether any ideas are due to causes really private.
And thus one may truly be said to see dark