An Essay Concerning Human Understanding by John Locke - HTML preview

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Chapter IV

Of the Reality of Knowledge

1. Objection. "Knowledge placed in our ideas may be all unreal or chimerical." I doubt not but my

reader, by this time, may be apt to think that I have been all this while only building a castle in the

air; and be ready to say to me:

"To what purpose all this stir? Knowledge, say you, is only the perception of the agreement or

disagreement of our own ideas: but who knows what those ideas may be? Is there anything so

extravagant as the imaginations of men's brains? Where is the head that has no chimeras in it? Or if

there be a sober and a wise man, what difference will there be, by your rules, between his

knowledge and that of the most extravagant fancy in the world? They both have their ideas, and

perceive their agreement and disagreement one with another. If there be any difference between

them, the advantage will be on the warm-headed man's side, as having the more ideas, and the

more lively. And so, by your rules, he will be the more knowing. If it be true, that all knowledge lies

only in the perception of the agreement or disagreement of our own ideas, the visions of an

enthusiast and the reasonings of a sober man will be equally certain. It is no matter how things are:

so a man observe but the agreement of his own imaginations, and talk conformably, it is all truth, all

certainty. Such castles in the air will be as strongholds of truth, as the demonstrations of Euclid.

That an harpy is not a centaur is by this way as certain knowledge, and as much a truth, as that a

square is not a circle."

"But of what use is all this fine knowledge of men's own imaginations, to a man that inquires after

the reality of things? It matters not what men's fancies are, it is the knowledge of things that is only

to be prized: it is this alone gives a value to our reasonings, and preference to one man's knowledge

over another's, that it is of things as they really are, and not of dreams and fancies."

2. Answer: "Not so, where ideas agree with things." To which I answer, That if our knowledge of our

ideas terminate in them, and reach no further, where there is something further intended, our most

serious thoughts will be of little more use than the reveries of a crazy brain; and the truths built

thereon of no more weight than the discourses of a man who sees things clearly in a dream, and

with great assurance utters them. But I hope, before I have done, to make it evident, that this way of

certainty, by the knowledge of our own ideas, goes a little further than bare imagination: and I

believe it will appear that all the certainty of general truths a man has lies in nothing else.

3. But what shall be the criterion of this agreement? It is evident the mind knows not things

immediately, but only by the intervention of the ideas it has of them. Our knowledge, therefore is real

only so far as there is a conformity between our ideas and the reality of things. But what shall be

here the criterion? How shall the mind, when it perceives nothing but its own ideas, know that they

agree with things themselves? This, though it seems not to want difficulty, yet, I think, there be two

sorts of ideas that we may be assured agree with things.

4. As all simple ideas are really conformed to things. First, The first are simple ideas, which since

the mind, as has been shown, can by no means make to itself, must necessarily be the product of

things operating on the mind, in a natural way, and producing therein those perceptions which by

the Wisdom and Will of our Maker they are ordained and adapted to. From whence it follows, that

simple ideas are not fictions of our fancies, but the natural and regular productions of things without

us, really operating upon us; and so carry with them all the conformity which is intended; or which

our state requires: for they represent to us things under those appearances which they are fitted to

produce in us: whereby we are enabled to distinguish the sorts of particular substances, to discern

the states they are in, and so to take them for our necessities, and apply them to our uses. Thus the

idea of whiteness, or bitterness, as it is in the mind, exactly answering that power which is in any

body to produce it there, has all the real conformity it can or ought to have, with things without us.

And this conformity between our simple ideas and the existence of things, is sufficient for real

knowledge.

5. All complex ideas, except ideas of substances, are their own archetypes. Secondly, All our

complex ideas, except those of substances, being archetypes of the mind's own making, not

intended to be the copies of anything, nor referred to the existence of anything, as to their originals,

cannot want any conformity necessary to real knowledge. For that which is not designed to

represent anything but itself, can never be capable of a wrong representation, nor mislead us from

the true apprehension of anything, by its dislikeness to it: and such, excepting those of substances,

are all our complex ideas. Which, as I have shown in another place, are combinations of ideas,

which the mind, by its free choice, puts together, without considering any connexion they have in

nature. And hence it is, that in all these sorts the ideas themselves are considered as the

archetypes, and things no otherwise regarded, but as they are conformable to them. So that we

cannot but be infallibly certain, that all the knowledge we attain concerning these ideas is real, and

reaches things themselves. Because in all our thoughts, reasonings, and discourses of this kind, we

intend things no further than as they are conformable to our ideas. So that in these we cannot miss

of a certain and undoubted reality.

6. Hence the reality of mathematical knowledge. I doubt not but it will be easily granted, that the

knowledge we have of mathematical truths is not only certain, but real knowledge; and not the bare

empty vision of vain, insignificant chimeras of the brain: and yet, if we will consider, we shall find

that it is only of our own ideas. The mathematician considers the truth and properties belonging to a

rectangle or circle only as they are in idea in his own mind. For it is possible he never found either of

them existing mathematically, i.e., precisely true, in his life. But yet the knowledge he has of any

truths or properties belonging to a circle, or any other mathematical figure, are nevertheless true and

certain, even of real things existing: because real things are no further concerned, nor intended to

be meant by any such propositions, than as things really agree to those archetypes in his mind. Is it

true of the idea of a triangle, that its three angles are equal to two right ones? It is true also of a

triangle, wherever it really exists. Whatever other figure exists, that it is not exactly answerable to

that idea of a triangle in his mind, is not at all concerned in that proposition. And therefore he is

certain all his knowledge concerning such ideas is real knowledge: because, intending things no

further than they agree with those his ideas, he is sure what he knows concerning those figures,

when they have barely an ideal existence in his mind, will hold true of them also when they have a

real existence in matter: his consideration being barely of those figures, which are the same

wherever or however they exist.

7. And of moral. And hence it follows that moral knowledge is as capable of real certainty as

mathematics. For certainty being but the perception of the agreement or disagreement of our ideas,

and demonstration nothing but the perception of such agreement, by the intervention of other ideas

or mediums; our moral ideas, as well as mathematical, being archetypes themselves, and so

adequate and complete ideas; all the agreement or disagreement which we shall find in them will

produce real knowledge, as well as in mathematical figures.

8. Existence not required to make abstract knowledge real. For the attaining of knowledge and

certainty, it is requisite that we have determined ideas: and, to make our knowledge real, it is

requisite that the ideas answer their archetypes. Nor let it be wondered, that I place the certainty of

our knowledge in the consideration of our ideas, with so little care and regard (as it may seem) to

the real existence of things: since most of those discourses which take up the thoughts and engage

the disputes of those who pretend to make it their business to inquire after truth and certainty, will, I

presume, upon examination, be found to be general propositions, and notions in which existence is

not at all concerned. All the discourses of the mathematicians about the squaring of a circle, conic

sections, or any other part of mathematics, concern not the existence of any of those figures: but

their demonstrations, which depend on their ideas, are the same, whether there be any square or

circle existing in the world or no. In the same manner, the truth and certainty of moral discourses

abstracts from the lives of men, and the existence of those virtues in the world whereof they treat:

nor are Tully's Offices less true, because there is nobody in the world that exactly practises his

rules, and lives up to that pattern of a virtuous man which he has given us, and which existed

nowhere when he writ but in idea. If it be true in speculation, i.e., in idea, that murder deserves

death, it will also be true in reality of any action that exists conformable to that idea of murder. As for

other actions, the truth of that proposition concerns them not. And thus it is of all other species of

things, which have no other essences but those ideas which are in the minds of men.

9. Nor will it be less true or certain, because moral ideas are of our own making and naming. But it

will here be said, that if moral knowledge be placed in the contemplation of our own moral ideas,

and those, as other modes, be of our own making, What strange notions will there be of justice and

temperance? What confusion of virtues and vice, if every one may make what ideas of them he

pleases? No confusion or disorder in the things themselves, nor the reasonings about them; no

more than (in mathematics) there would be a disturbance in the demonstration, or a change in the

properties of figures, and their relations one to another, if a man should make a triangle with four

corners, or a trapezium with four right angles: that is, in plain English, change the names of the

figures, and call that by one name, which mathematicians call ordinarily by another. For, let a man

make to himself the idea of a figure with three angles, whereof one is a right one, and call it, if he

please, equilaterum or trapezium, or anything else; the properties of, and demonstrations about that

idea will be the same as if he called it a rectangular triangle. I confess the change of the name, by

the impropriety of speech, will at first disturb him who knows not what idea it stands for: but as soon

as the figure is drawn, the consequences and demonstrations are plain and clear. Just the same is it

in moral knowledge: let a man have the idea of taking from others, without their consent, what their

honest industry has possessed them of, and call this justice if he please. He that takes the name

here without the idea put to it will be mistaken, by joining another idea of his own to that name: but

strip the idea of that name, or take it such as it is in the speaker's mind, and the same things will

agree to it, as if you called it injustice. Indeed, wrong names in moral discourses breed usually more

disorder, because they are not so easily rectified as in mathematics, where the figure, once drawn

and seen, makes the name useless and of no force. For what need of a sign, when the thing

signified is present and in view? But in moral names, that cannot be so easily and shortly done,

because of the many decompositions that go to the making up the complex ideas of those modes.

But yet for all this, the miscalling of any of those ideas, contrary to the usual signification of the

words of that language, hinders not but that we may have certain and demonstrative knowledge of

their several agreements and disagreements, if we will carefully, as in mathematics, keep to the

same precise ideas, and trace them in their several relations one to another, without being led away

by their names. If we but separate the idea under consideration from the sign that stands for it, our

knowledge goes equally on in the discovery of real truth and certainty, whatever sounds we make

use of.

10. Misnaming disturbs not the certainty of the knowledge. One thing more we are to take notice of,

That where God or any other law-maker, hath defined any moral names, there they have made the

essence of that species to which that name belongs; and there it is not safe to apply or use them

otherwise: but in other cases it is bare impropriety of speech to apply them contrary to the common

usage of the country. But yet even this too disturbs not the certainty of that knowledge, which is still

to be had by a due contemplation and comparing of those even nicknamed ideas.

11. Our complex ideas of substances have their archetypes without us; and here knowledge comes

short. Thirdly, There is another sort of complex ideas, which, being referred to archetypes without

us, may differ from them, and so our knowledge about them may come short of being real. Such are

our ideas of substances, which, consisting of a collection of simple ideas, supposed taken from the

works of nature, may yet vary from them; by having more or different ideas united in them than are

to be found united in the things themselves. From whence it comes to pass, that they may, and

often do, fail of being exactly conformable to things themselves.

12. So far as our complex ideas agree with those archetypes without us, so far our knowledge

concerning substances is real. I say, then, that to have ideas of substances which, by being

conformable to things, may afford us real knowledge, it is not enough, as in modes, to put together

such ideas as have no inconsistence, though they did never before so exist: v.g. the ideas of

sacrilege or perjury, etc., were as real and true ideas before, as after the existence of any such fact.

But our ideas of substances, being supposed copies, and referred to archetypes without us, must

still be taken from something that does or has existed: they must not consist of ideas put together at

the pleasure of our thoughts, without any real pattern they were taken from, though we can perceive

no inconsistence in such a combination. The reason whereof is, because we, knowing not what real

constitution it is of substances whereon our simple ideas depend, and which really is the cause of

the strict union of some of them one with another, and the exclusion of others there are very few of

them that we can be sure are or are not inconsistent in nature, any further than experience and

sensible observation reach. Herein, therefore, is founded the reality of our knowledge concerning

substances--That all our complex ideas of them must be such, and such only, as are made up of

such simple ones as have been discovered to co-exist in nature. And our ideas being thus true,

though not perhaps very exact copies, are yet the subjects of real (as far as we have any)

knowledge of them. Which (as has been already shown) will not be found to reach very far: but so

far as it does, it will still be real knowledge. Whatever ideas we have, the agreement we find they

have with others will still be knowledge. If those ideas be abstract, it will be general knowledge. But

to make it real concerning substances, the ideas must be taken from the real existence of things.

Whatever simple ideas have been found to co-exist in any substance, these we may with

confidence join together again, and so make abstract ideas of substances. For whatever have once

had an union in nature, may be united again.

13. In our inquiries about substances, we must consider ideas, and not confine our thoughts to

names or species supposed set out by names. This, if we rightly consider, and confine not our

thoughts and abstract ideas to names, as if there were, or could be no other sorts of things than

what known names had already determined, and, as it were, set out, we should think of things with

greater freedom and less confusion than perhaps we do. It would possibly be thought a bold

paradox, if not a very dangerous falsehood, if I should say that some changelings, who have lived

forty years together, without any appearance of reason, are something between a man and a beast:

which prejudice is founded upon nothing else but a false supposition, that these two names, man

and beast, stand for distinct species so set out by real essences, that there can come no other

species between them: whereas if we will abstract from those names, and the supposition of such

specific essences made by nature, wherein all things of the same denominations did exactly and

equally partake; if we would not fancy that there were a certain number of these essences, wherein

all things, as in moulds, were cast and formed; we should find that the idea of the shape, motion,

and life of a man without reason, is as much a distinct idea, and makes as much a distinct sort of

things from man and beast, as the idea of the shape of an ass with reason would be different from

either that of man or beast, and be a species of an animal between, or distinct from both.

14. Objection against a changeling being something between a man and beast, answered. Here

everybody will be ready to ask, If changelings may be supposed something between man and

beast, pray what are they? I answer, changelings; which is as good a word to signify something

different from the signification of man or beast, as the names man and beast are to have

significations different one from the other. This, well considered, would resolve this matter, and

show my meaning without any more ado. But I am not so unacquainted with the zeal of some men,

which enables them to spin consequences, and to see religion threatened, whenever any one

ventures to quit their forms of speaking, as not to foresee what names such a proposition as this is

like to be charged with: and without doubt it will be asked, If changelings are something between

man and beast, what will become of them in the other world? To which I answer, I. It concerns me

not to know or inquire. To their own master they stand or fall. It will make their state neither better

nor worse, whether we determine anything of it or no. They are in the hands of a faithful Creator and

a bountiful Father, who disposes not of his creatures according to our narrow thoughts or opinions,

nor distinguishes them according to names and species of our contrivance. And we that know so

little of this present world we are in, may, I think, content ourselves without being peremptory in

defining the different states which creatures shall come into when they go off this stage. It may

suffice us, that He hath made known to al those who are capable of instruction, discoursing, and

reasoning, that they shall come to an account, and receive according to what they have done in this

body.

15. What will become of changelings in a future state? But, Secondly, I answer, The force of these

men's question (viz., Will you deprive changelings of a future state?) is founded on one of these two

suppositions, which are both false. The first is, That al things that have the outward shape and

appearance of a man must necessarily be designed to an immortal future being after this life: or,

secondly, That whatever is of human birth must be so. Take away these imaginations, and such

questions will be groundless and ridiculous. I desire then those who think there is no more but an

accidental difference between themselves and changelings, the essence in both being exactly the

same, to consider, whether they can imagine immortality annexed to any outward shape of the

body; the very proposing it is, I suppose, enough to make them disown it. No one yet, that ever I

heard of, how much soever immersed in matter, allowed that excellency to any figure of the gross

sensible outward parts, as to affirm eternal life due to it, or a necessary consequence of it; or that

any mass of matter should, after its dissolution here, be again restored hereafter to an everlasting

state of sense, perception, and knowledge, only because it was moulded into this or that figure, and

had such a particular frame of its visible parts. Such an opinion as this, placing immortality in a

certain superficial figure, turns out of doors all consideration of soul or spirit; upon whose account

alone some corporeal beings have hitherto been concluded immortal, and others not. This is to

attribute more to the outside than inside of things; and to place the excellency of a man more in the

external shape of his body, than internal perfections of his soul: which is but little better than to

annex the great and inestimable advantage of immortality and life everlasting, which he has above

other material beings, to annex it, I say, to the cut of his beard, or the fashion of his coat. For this or

that outward mark of our bodies no more carries with it the hope of an eternal duration, than the

fashion of a man's suit gives him reasonable grounds to imagine it will never wear out, or that it will

make him immortal. It will perhaps be said, that nobody thinks that the shape makes anything

immortal, but it is the shape is the sign of a rational soul within, which is immortal. I wonder who

made it the sign of any such thing: for barely saying it, will not make it so. It would require some

proofs to persuade one of it. No figure that I know speaks any such language. For it may as

rationally be concluded, that the dead body of a man, wherein there is to be found no more

appearance or action of life than there is in a statue, has yet nevertheless a living soul in it, because

of its shape; as that there is a rational soul in a changeling, because he has the outside of a rational

creature, when his actions carry far less marks of reason with them, in the whole course of his life,

than what are to be found in many a beast.

16. Monsters. But it is the issue of rational parents, and must therefore be concluded to have a

rational soul. I know not by what logic you must so conclude. I am sure this is a conclusion that men

nowhere allow of. For if they did, they would not make bold, as everywhere they do, to destroy ill-

formed and mis-shaped productions. Ay, but these are monsters. Let them be so: what will your

drivelling, unintelligent, intractable changeling be? Shall a defect in the body make a monster; a

defect in the mind (the far more noble, and, in the common phrase, the far more essential part) not?

Shall the want of a nose, or a neck, make a monster, and put such issue out of the rank of men; the

want of reason and understanding, not? This is to bring all back again to what was exploded just

now: this is to place all in the shape, and to take the measure of a man only by his outside. To show

that according to the ordinary way of reasoning in this matter, people do lay the whole stress on the

figure, and resolve the whole essence of the species of man (as they make it) into the outward

shape, how unreasonable soever it be, and how much soever they disown it, we need but trace their

thoughts and practice a little further, and then it will plainly appear. The well-shaped changeling is a

man, has a rational soul, though it appear not: this is past doubt, say you: make the ears a little

longer, and more pointed, and the nose a little flatter than ordinary, and then you begin to boggle:

make the face yet narrower, flatter, and longer, and then you are at a stand: add still more and more

of the likeness of a brute to it, and let the head be perfectly that of some other animal, then presently

it is a monster; and it is demonstration with you that it hath no rational soul, and must be destroyed.

Where now (I ask) shall be the just measure; which the utmost bounds of that shape, that carries

with it a rational soul? For, since there have been human foetuses produced, half beast and half

man; and others three parts one, and one part the other; and so it is possible they may be in all the

variety of approaches to the one or the other shape, and may have several degrees of mixture of the

likeness of a man, or a brute;--I would gladly know what are those precise lineaments, which,

according to this hypothesis, are or are not capable of a rational soul to be joined to them. What sort

of outside is the certain sign that there is or is not such an inhabitant within? For till that be done, we

talk at random of man: and shall always, I fear, do so, as long as we give ourselves up to certain

sounds, and the imaginations of settled and fixed species in nature, we know not what. But, after all,

I desire it may be considered, that those who think they have answered the difficulty, by telling us,

that a mis-shaped foetus is a monster, run into the same fault they are arguing against; by

constituting a species between man and beast. For what else, I pray, is their monster in the case, (if

the word monster signifies anything at all,) but something neither man nor beast, but partaking

somewhat of either? And just so is the changeling before mentioned. So necessary is it to quit the

common notion of species and essences, if we will truly look into the nature of