OF OUR KNOWLEDGE OF THE EXISTENCE OF OTHER THINGS.
1. Knowledge of the existence of other Finite Beings is to be had only
by actual Sensation.
The knowledge of our own being we have by intuition. The existence of a
God, reason clearly makes known to us, as has been shown.
The knowledge of the existence of ANY OTHER THING we can have only by
SENSATION: for there being no necessary connexion of real existence with
any IDEA a man hath in his memory; nor of any other existence but that
of God with the existence of any particular man: no particular man
can know the existence of any other being, but only when, by actual
operating upon him, it makes itself perceived by him. For, the having
the idea of anything in our mind, no more proves the existence of that
thing, than the picture of a man evidences his being in the world, or
the visions of a dream make thereby a true history.
2. Instance: Whiteness of this Paper.
It is therefore the ACTUAL RECEIVING of ideas from without that gives
us notice of the existence of other things, and makes us know, that
something doth exist at that time without us, which causes that idea in
us; though perhaps we neither know nor consider how it does it. For it
takes not from the certainty of our senses, and the ideas we receive by
them, that we know not the manner wherein they are produced: v.g. whilst
I write this, I have, by the paper affecting my eyes, that idea produced
in my mind, which, whatever object causes, I call WHITE; by which I know
that that quality or accident (i.e. whose appearance before my eyes
always causes that idea) doth really exist, and hath a being without me.
And of this, the greatest assurance I can possibly have, and to which my
faculties can attain, is the testimony of my eyes, which are the proper
and sole judges of this thing; whose testimony I have reason to rely on
as so certain, that I can no more doubt, whilst I write this, that I
see white and black, and that something really exists that causes that
sensation in me, than that I write or move my hand; which is a certainty
as great as human nature is capable of, concerning the existence of
anything, but a man's self alone, and of God.
3. This notice by our Senses, though not so certain as Demonstration,
yet may be called Knowledge, and proves the Existence of Things without
us.
The notice we have by our senses of the existing of things without us,
though it be not altogether so certain as our intuitive knowledge, or
the deductions of our reason employed about the clear abstract ideas
of our own minds; yet it is an assurance that deserves the name of
KNOWLEDGE. If we persuade ourselves that our faculties act and inform
us right concerning the existence of those objects that affect them, it
cannot pass for an ill-grounded confidence: for I think nobody can, in
earnest, be so sceptical as to be uncertain of the existence of those
things which he sees and feels. At least, he that can doubt so far,
(whatever he may have with his own thoughts,) will never have any
controversy with me; since he can never be sure I say anything contrary
to his own opinion. As to myself, I think God has given me assurance
enough of the existence of things without me: since, by their different
application, I can produce in myself both pleasure and pain, which
is one great concernment of my present state. This is certain: the
confidence that our faculties do not herein deceive us, is the greatest
assurance we are capable of concerning the existence of material beings.
For we cannot act anything but by our faculties; nor talk of knowledge
itself, but by the help of those faculties which are fitted to apprehend
even what knowledge is.
But besides the assurance we have from our senses themselves, that they
do not err in the information they give us of the existence of things
without us, when they are affected by them, we are further confirmed in
this assurance by other concurrent reasons:--
4. I. Confirmed by concurrent reasons:--First, Because we cannot have
ideas of Sensation but by the Inlet of the Senses.
It is plain those perceptions are produced in us by exterior causes
affecting our senses: because those that want the ORGANS of any sense,
never can have the ideas belonging to that sense produced in their
minds. This is too evident to be doubted: and therefore we cannot but be
assured that they come in by the organs of that sense, and no other way.
The organs themselves, it is plain, do not produce them: for then the
eyes of a man in the dark would produce colours, and his nose smell
roses in the winter: but we see nobody gets the relish of a pineapple,
till he goes to the Indies, where it is, and tastes it.
5. II. Secondly, Because we find that an Idea from actual Sensation, and
another from memory, are very distinct Perceptions.
Because sometimes I find that I CANNOT AVOID THE HAVING THOSE IDEAS
PRODUCED IN MY MIND. For though, when my eyes are shut, or windows fast,
I can at pleasure recal to my mind the ideas of light, or the sun, which
former sensations had lodged in my memory; so I can at pleasure lay by
THAT idea, and take into my view that of the smell of a rose, or taste
of sugar. But, if I turn my eyes at noon towards the sun, I cannot avoid
the ideas which the light or sun then produces in me. So that there is a
manifest difference between the ideas laid up in my memory, (over which,
if they were there only, I should have constantly the same power to
dispose of them, and lay them by at pleasure,) and those which force
themselves upon me, and I cannot avoid having. And therefore it must
needs be some exterior cause, and the brisk acting of some objects
without me, whose efficacy I cannot resist, that produces those ideas
in my mind, whether I will or no. Besides, there is nobody who doth not
perceive the difference in himself between contemplating the sun, as
he hath the idea of it in his memory, and actually looking upon it: of
which two, his perception is so distinct, that few of his ideas are
more distinguishable one from another. And therefore he hath certain
knowledge that they are not BOTH memory, or the actions of his mind, and
fancies only within him; but that actual seeing hath a cause without.
6. III. Thirdly, Because Pleasure or Pain, which accompanies actual
Sensation, accompanies not the returning of those Ideas without the
external Objects.
Add to this, that many of those ideas are PRODUCED IN US WITH PAIN,
which afterwards we remember without the least offence. Thus, the pain
of heat or cold, when the idea of it is revived in our minds, gives us
no disturbance; which, when felt, was very troublesome; and is again,
when actually repeated: which is occasioned by the disorder the external
object causes in our bodies when applied to them: and we remember the
pains of hunger, thirst, or the headache, without any pain at all; which
would either never disturb us, or else constantly do it, as often as we
thought of it, were there nothing more but ideas floating in our minds,
and appearances entertaining our fancies, without the real existence
of things affecting us from abroad. The same may be said of PLEASURE,
accompanying several actual sensations. And though mathematical
demonstration depends not upon sense, yet the examining them by diagrams
gives great credit to the evidence of our sight, and seems to give it a
certainty approaching to that of demonstration itself. For, it would be
very strange, that a man should allow it for an undeniable truth, that
two angles of a figure, which he measures by lines and angles of a
diagram, should be bigger one than the other, and yet doubt of the
existence of those lines and angles, which by looking on he makes use of
to measure that by.
7. IV. Fourthly, Because our Senses assist one another's Testimony of
the Existence of outward Things, and enable us to predict.
Our SENSES in many cases BEAR WITNESS TO THE TRUTH OF EACH OTHER'S
REPORT, concerning the existence of sensible things without us. He that
SEES a fire, may, if he doubt whether it be anything more than a bare
fancy, FEEL it too; and be convinced, by putting his hand in it. Which
certainly could never be put into such exquisite pain by a bare idea or
phantom, unless that the pain be a fancy too: which yet he cannot, when
the burn is well, by raising the idea of it, bring upon himself again.
Thus I see, whilst I write this, I can change the appearance of the
paper; and by designing the letters, tell BEFOREHAND what new idea it
shall exhibit the very next moment, by barely drawing my pen over it:
which will neither appear (let me fancy as much as I will) if my hands
stand still; or though I move my pen, if my eyes be shut: nor, when
those characters are once made on the paper, can I choose afterwards but
see them as they are; that is, have the ideas of such letters as I have
made. Whence it is manifest, that they are not barely the sport and play
of my own imagination, when I find that the characters that were made at
the pleasure of my own thoughts, do not obey them; nor yet cease to be,
whenever I shall fancy it, but continue to affect my senses constantly
and regularly, according to the figures I made them. To which if we will
add, that the sight of those shall from another man, draw such sounds as
I beforehand design they shall stand for, there will be little reason
left to doubt that those words I write do really exist without me, when
they cause a long series of regular sounds to affect my ears, which
could not be the effect of my imagination, nor could my memory retain
them in that order.
8. This Certainty is as great as our Condition needs.
But yet, if after all this any one will be so sceptical as to distrust
his senses, and to affirm that all we see and hear, feel and taste,
think and do, during our whole being, is but the series and deluding
appearances of a long dream, whereof there is no reality; and therefore
will question the existence of all things, or our knowledge of anything:
I must desire him to consider, that, if all be a dream, then he doth but
dream that he makes the question, and so it is not much matter that a
waking man should answer him. But yet, if he pleases, he may dream that
I make him this answer, That the certainty of things existing in RERUM
NATURA when we have the testimony of our senses for it is not only as
great as our frame can attain to, but as our condition needs. For,
our faculties being suited not to the full extent of being, nor to a
perfect, clear, comprehensive knowledge of things free from all doubt
and scruple; but to the preservation of us, in whom they are; and
accommodated to the use of life: they serve to our purpose well enough,
if they will but give us certain notice of those things, which are
convenient or inconvenient to us. For he that sees a candle burning, and
hath experimented the force of its flame by putting his finger in it,
will little doubt that this is something existing without him, which
does him harm, and puts him to great pain: which is assurance enough,
when no man requires greater certainty to govern his actions by than
what is as certain as his actions themselves. And if our dreamer pleases
to try whether the glowing heat of a glass furnace be barely a wandering
imagination in a drowsy man's fancy, by putting his hand into it, he may
perhaps be wakened into a certainty greater than he could wish, that it
is something more than bare imagination. So that this evidence is as
great as we can desire, being as certain to us as our pleasure or pain,
i.e. happiness or misery; beyond which we have no concernment, either of
knowing or being. Such an assurance of the existence of things without
us is sufficient to direct us in the attaining the good and avoiding the
evil which is caused by them, which is the important concernment we have
of being made acquainted with them.
9. But reaches no further than actual Sensation.
In fine, then, when our senses do actually convey into our
understandings any idea, we cannot but be satisfied that there doth
something AT THAT TIME really exist without us, which doth affect our
senses, and by them give notice of itself to our apprehensive faculties,
and actually produce that idea which we then perceive: and we cannot
so far distrust their testimony, as to doubt that such COLLECTIONS of
simple ideas as we have observed by our senses to be united together, do
really exist together. But this knowledge extends as far as the present
testimony of our senses, employed about particular objects that do then
affect them, and no further. For if I saw such a collection of simple
ideas as is wont to be called MAN, existing together one minute since,
and am now alone, I cannot be certain that the same man exists now,
since there is no NECESSARY CONNEXION of his existence a minute since
with his existence now: by a thousand ways he may cease to be, since I
had the testimony of my senses for his existence. And if I cannot be
certain that the man I saw last to-day is now in being, I can less be
certain that he is so who hath been longer removed from my senses, and I
have not seen since yesterday, or since the last year: and much less can
I be certain of the existence of men that I never saw. And, therefore,
though it be highly probable that millions of men do now exist, yet,
whilst I am alone, writing this, I have not that certainty of it which
we strictly call knowledge; though the great likelihood of it puts me
past doubt, and it be reasonable for me to do several things upon the
confidence that there are men (and men also of my acquaintance, with
whom I have to do) now in the world: but this is but probability, not
knowledge.
10. Folly to expect Demonstration in everything.
Whereby yet we may observe how foolish and vain a thing it is for a
man of a narrow knowledge, who having reason given him to judge of
the different evidence and probability of things, and to be swayed
accordingly; how vain, I say, it is to expect demonstration and
certainty in things not capable of it; and refuse assent to very
rational propositions, and act contrary to very plain and clear truths,
because they cannot be made out so evident, as to surmount every the
least (I will not say reason, but) pretence of doubting. He that, in
the ordinary affairs of life, would admit of nothing but direct plain
demonstration, would be sure of nothing in this world, but of perishing
quickly. The wholesomeness of his meat or drink would not give him
reason to venture on it: and I would fain know what it is he could do
upon such grounds as are capable of no doubt, no objection.
11. Past Existence of other things is known by Memory.
As WHEN OUR SENSES ARE ACTUALLY EMPLOYED ABOUT ANY OBJECT, we do know
that it does exist; so BY OUR MEMORY we may be assured, that heretofore
things that affected our senses have existed. And thus we have knowledge
of the past existence of several things, whereof our senses having
informed us, our memories still retain the ideas; and of this we are
past all doubt, so long as we remember well. But this knowledge also
reaches no further than our senses have formerly assured us. Thus,
seeing water at this instant, it is an unquestionable truth to me that
water doth exist: and remembering that I saw it yesterday, it will also
be always true, and as long as my memory retains it always an undoubted
proposition to me, that water did exist the 10th of July, 1688; as it
will also be equally true that a certain number of very fine colours did
exist, which at the same time I saw upon a bubble of that water: but,
being now quite out of sight both of the water and bubbles too, it is no
more certainly known to me that the water doth now exist, than that the
bubbles or colours therein do so: it being no more necessary that water
should exist to-day, because it existed yesterday, than that the colours
or bubbles exist to-day, because they existed yesterday, though it be
exceedingly much more probable; because water hath been observed to
continue long in existence, but bubbles, and the colours on them,
quickly cease to be.
12. The Existence of other finite Spirits not knowable, and rests on
Faith.
What ideas we have of spirits, and how we come by them, I have already
shown. But though we have those ideas in our minds, and know we have
them there, the having the ideas of spirits does not make us know that
any such things do exist without us, or that there are any finite
spirits, or any other spiritual beings, but the Eternal God. We have
ground from revelation, and several other reasons, to believe with
assurance that there are such creatures: but our senses not being
able to discover them, we want the means of knowing their particular
existences. For we can no more know that there are finite spirits really
existing, by the idea we have of such beings in our minds, than by the
ideas any one has of fairies or centaurs, he can come to know that
things answering those ideas do really exist.
And therefore concerning the existence of finite spirits, as well as
several other things, we must content ourselves with the evidence of
faith; but universal, certain propositions concerning this matter
are beyond our reach. For however true it may be, v.g., that all the
intelligent spirits that God ever created do still exist, yet it
can never make a part of our certain knowledge. These and the like
propositions we may assent to, as highly probable, but are not, I fear,
in this state capable of knowing. We are not, then, to put others upon
demonstrating, nor ourselves upon search of universal certainty in all
those matters; wherein we are not capable of any other knowledge, but
what our senses give us in this or that particular.
13. Only particular Propositions concerning concrete Existances are
knowable.
By which it appears that there are two sorts of propositions:--(1)
There is one sort of propositions concerning the existence of anything
answerable to such an idea: as having the idea of an elephant, phoenix,
motion, or an angel, in my mind, the first and natural inquiry is,
Whether such a thing does anywhere exist? And this knowledge is only of
particulars. No existence of anything without us, but only of God, can
certainly be known further than our senses inform us, (2) There is
another sort of propositions, wherein is expressed the agreement or
disagreement of OUR ABSTRACT IDEAS, and their dependence on one another.
Such propositions may be universal and certain. So, having the idea of
God and myself, of fear and obedience, I cannot but be sure that God is
to be feared and obeyed by me: and this proposition will be certain,
concerning man in general, if I have made an abstract idea of such a
species, whereof I am one particular. But yet this proposition, how
certain soever, that 'men ought to fear and obey God' proves not to
me the EXISTENCE of MEN in the world; but will be true of all such
creatures, whenever they do exist: which certainty of such general
propositions depends on the agreement or disagreement to be discovered
in those abstract ideas.
14. And all general Propositions that are known to be true concern
abstract Ideas.
In the former case, our knowledge is the consequence of the existence
of things, producing ideas in our minds by our senses: in the latter,
knowledge is the consequence of the ideas (be they what they will) that
are in our minds, producing there general certain propositions. Many of
these are called AETERNAE VERITATES, and all of them indeed are so; not
from being written, all or any of them, in the minds of all men; or that
they were any of them propositions in any one's mind, till he, having
got the abstract ideas, joined or separated them by affirmation or
negation. But wheresoever we can suppose such a creature as man is,
endowed with such faculties, and thereby furnished with such ideas as we
have, we must conclude, he must needs, when he applies his thoughts to
the consideration of his ideas, know the truth of certain propositions
that will arise from the agreement or disagreement which he will
perceive in his own ideas. Such propositions are therefore called
ETERNAL TRUTHS, not because they are eternal propositions actually
formed, and antecedent to the understanding that at any time makes them;
nor because they are imprinted on the mind from any patterns that are
anywhere out of the mind, and existed before: but because, being once
made about abstract ideas, so as to be true, they will, whenever they
can be supposed to be made again at any time, past or come, by a mind
having those ideas, always actually be true. For names being supposed
to stand perpetually for the same ideas, and the same ideas having
immutably the same habitudes one to another, propositions concerning any
abstract ideas that are once true must needs be ETERNAL VERITIES.