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An Essay Concerning Human Understanding

As thou knowest not what is the way of the Spirit, nor how the bones do grow in the womb of her

that is with child: even so thou knowest not the works of God, who maketh all things.--Eccles. 11. 5.

Quam bellum est velle confiteri potius nescire quod nescias, quam ista effutientem nauseare, atque

ipsum sibi displicere.--Cicero, de Natur. Deor. l. i.


1. An Inquiry into the understanding, pleasant and useful. Since it is the understanding that sets

man above the rest of sensible beings, and gives him all the advantage and dominion which he has

over them; it is certainly a subject, even for its nobleness, worth our labour to inquire into. The

understanding, like the eye, whilst it makes us see and perceive all other things, takes no notice of

itself; and it requires art and pains to set it at a distance and make it its own object. But whatever be

the difficulties that lie in the way of this inquiry; whatever it be that keeps us so much in the dark to

ourselves; sure I am that all the light we can let in upon our minds, all the acquaintance we can

make with our own understandings, will not only be very pleasant, but bring us great advantage, in

directing our thoughts in the search of other things.

2. Design. This, therefore, being my purpose--to inquire into the original, certainty, and extent of

human knowledge, together with the grounds and degrees of belief, opinion, and assent;--I shall not

at present meddle with the physical consideration of the mind; or trouble myself to examine wherein

its essence consists; or by what motions of our spirits or alterations of our bodies we come to have

any sensation by our organs, or any ideas in our understandings; and whether those ideas do in

their formation, any or all of them, depend on matter or not. These are speculations which, however

curious and entertaining, I shall decline, as lying out of my way in the design I am now upon. It shall

suffice to my present purpose, to consider the discerning faculties of a man, as they are employed

about the objects which they have to do with. And I shall imagine I have not wholly misemployed

myself in the thoughts I shall have on this occasion, if, in this historical, plain method, I can give any

account of the ways whereby our understandings come to attain those notions of things we have;

and can set down any measures of the certainty of our knowledge; or the grounds of those

persuasions which are to be found amongst men, so various, different, and wholly contradictory; and

yet asserted somewhere or other with such assurance and confidence, that he that shall take a view

of the opinions of mankind, observe their opposition, and at the same time consider the fondness

and devotion wherewith they are embraced, the resolution and eagerness wherewith they are

maintained, may perhaps have reason to suspect, that either there is no such thing as truth at all, or

that mankind hath no sufficient means to attain a certain knowledge of it.

3. Method. It is therefore worth while to search out the bounds between opinion and knowledge; and

examine by what measures, in things whereof we have no certain knowledge, we ought to regulate

our assent and moderate our persuasion. In order whereunto I shall pursue this following method:--

First, I shall inquire into the original of those ideas, notions, or whatever else you please to call

them, which a man observes, and is conscious to himself he has in his mind; and the ways whereby

the understanding comes to be furnished with them.

Secondly, I shall endeavour to show what knowledge the understanding hath by those ideas; and

the certainty, evidence, and extent of it.

Thirdly, I shall make some inquiry into the nature and grounds of faith or opinion: whereby I mean

that assent which we give to any proposition as true, of whose truth yet we have no certain

knowledge. And here we shall have occasion to examine the reasons and degrees of assent.

4. Useful to know the extent of our comprehension. If by this inquiry into the nature of the

understanding, I can discover the powers thereof; how far they reach; to what things they are in any

degree proportionate; and where they fail us, I suppose it may be of use to prevail with the busy

mind of man to be more cautious in meddling with things exceeding its comprehension; to stop

when it is at the utmost extent of its tether; and to sit down in a quiet ignorance of those things

which, upon examination, are found to be beyond the reach of our capacities. We should not then

perhaps be so forward, out of an affectation of an universal knowledge, to raise questions, and

perplex ourselves and others with disputes about things to which our understandings are not suited;

and of which we cannot frame in our minds any clear or distinct perceptions, or whereof (as it has

perhaps too often happened) we have not any notions at all. If we can find out how far the

understanding can extend its view; how far it has faculties to attain certainty; and in what cases it

can only judge and guess, we may learn to content ourselves with what is attainable by us in this


5. Our capacity suited to our state and concerns. For though the comprehension of our

understandings comes exceeding short of the vast extent of things, yet we shall have cause enough

to magnify the bountiful Author of our being, for that proportion and degree of knowledge he has

bestowed on us, so far above all the rest of the inhabitants of this our mansion. Men have reason to

be well satisfied with what God hath thought fit for them, since he hath given them (as St. Peter

says) {pana pros zoen kaieusebeian,} whatsoever is necessary for the conveniences of life and

information of virtue; and has put within the reach of their discovery, the comfortable provision for

this life, and the way that leads to a better. How short soever their knowledge may come of an

universal or perfect comprehension of whatsoever is, it yet secures their great concernments, that

they have light enough to lead them to the knowledge of their Maker, and the sight of their own

duties. Men may find matter sufficient to busy their heads, and employ their hands with variety,

delight, and satisfaction, if they will not boldly quarrel with their own constitution, and throw away the

blessings their hands are filled with, because they are not big enough to grasp everything. We shall

not have much reason to complain of the narrowness of our minds, if we will but employ them about

what may be of use to us; for of that they are very capable. And it will be an unpardonable, as well

as childish peevishness, if we undervalue the advantages of our knowledge, and neglect to improve

it to the ends for which it was given us, because there are some things that are set out of the reach

of it. It will be no excuse to an idle and untoward servant, who would not attend his business by

candle light, to plead that he had not broad sunshine. The Candle that is set up in us shines bright

enough for all our purposes. The discoveries we can make with this ought to satisfy us; and we shall

then use our understandings right, when we entertain all objects in that way and proportion that they

are suited to our faculties, and upon those grounds they are capable of being proposed to us; and

not peremptorily or intemperately require demonstration, and demand certainty, where probability

only is to be had, and which is sufficient to govern all our concernments. If we will disbelieve

everything, because we cannot certainly know al things, we shall do much what as wisely as he

who would not use his legs, but sit still and perish, because he had no wings to fly.

6. Knowledge of our capacity a cure of scepticism and idleness. When we know our own strength,

we shall the better know what to undertake with hopes of success; and when we have well surveyed

the powers of our own minds, and made some estimate what we may expect from them, we shall

not be inclined either to sit still, and not set our thoughts on work at all, in despair of knowing

anything; nor on the other side, question everything, and disclaim all knowledge, because some

things are not to be understood. It is of great use to the sailor to know the length of his line, though

he cannot with it fathom all the depths of the ocean. It is well he knows that it is long enough to

reach the bottom, at such places as are necessary to direct his voyage, and caution him against

running upon shoals that may ruin him. Our business here is not to know al things, but those which

concern our conduct. If we can find out those measures, whereby a rational creature, put in that

state in which man is in this world, may and ought to govern his opinions, and actions depending

thereon, we need not to be troubled that some other things escape our knowledge.

7. Occasion of this essay. This was that which gave the first rise to this Essay concerning the

understanding. For I thought that the first step towards satisfying several inquiries the mind of man

was very apt to run into, was, to take a survey of our own understandings, examine our own powers,

and see to what things they were adapted. Till that was done I suspected we began at the wrong

end, and in vain sought for satisfaction in a quiet and sure possession of truths that most concerned

us, whilst we let loose our thoughts into the vast ocean of Being; as if all that boundless extent were

the natural and undoubted possession of our understandings, wherein there was nothing exempt

from its decisions, or that escaped its comprehension. Thus men, extending their inquiries beyond

their capacities, and letting their thoughts wander into those depths where they can find no sure

footing, it is no wonder that they raise questions and multiply disputes, which, never coming to any

clear resolution, are proper only to continue and increase their doubts, and to confirm them at last in

perfect scepticism. Whereas, were the capacities of our understandings well considered, the extent

of our knowledge once discovered, and the horizon found which sets the bounds between the

enlightened and dark parts of things; between what is and what is not comprehensible by us, men

would perhaps with less scruple acquiesce in the avowed ignorance of the one, and employ their

thoughts and discourse with more advantage and satisfaction in the other.

8. What "Idea" stands for. Thus much I thought necessary to say concerning the occasion of this

Inquiry into human Understanding. But, before I proceed on to what I have thought on this subject, I

must here in the entrance beg pardon of my reader for the frequent use of the word idea, which he

will find in the following treatise. It being that term which, I think, serves best to stand for whatsoever

is the object of the understanding when a man thinks, I have used it to express whatever is meant

by phantasm, notion, species, or whatever it is which the mind can be employed about in thinking;

and I could not avoid frequently using it.

I presume it will be easily granted me, that there are such ideas in men's minds: every one is

conscious of them in himself; and men's words and actions will satisfy him that they are in others.

Our first inquiry then shall be,--how they come into the mind.