Clear and distinct ideas are terms which, though familiar and
frequent in men's mouths, I have reason to think every one who uses
does not perfectly understand. And possibly 'tis but here and there
one who gives himself the trouble to consider them so far as to know
what he himself or others precisely mean by them. I have therefore
in most places chose to put determinate or determined, instead of
clear and distinct, as more likely to direct men's thoughts to my
meaning in this matter. By those denominations, I mean some object
in the mind, and consequently determined, i.e. such as it is there
seen and perceived to be. This, I think, may fitly be called a
determinate or determined idea, when such as it is at any time
objectively in the mind, and so determined there, it is annexed, and
without variation determined, to a name or articulate sound, which
is to be steadily the sign of that very same object of the mind, or
determinate idea.

  To explain this a little more particularly. By determinate, when
applied to a simple idea, I mean that simple appearance which the mind
has in its view, or perceives in itself, when that idea is said to
be in it: by determined, when applied to a complex idea, I mean such
an one as consists of a determinate number of certain simple or less
complex ideas, joined in such a proportion and situation as the mind
has before its view, and sees in itself, when that idea is present
in it, or should be present in it, when a man gives a name to it. I
say should be, because it is not every one, nor perhaps any one, who
is so careful of his language as to use no word till he views in his
mind the precise determined idea which he resolves to make it the sign
of The want of this is the cause of no small obscurity and confusion
in men's thoughts and discourses.

  I know there are not words enough in any language to answer all
the variety of ideas that enter into men's discourses and
reasonings. But this hinders not but that when any one uses any
term, he may have in his mind a determined idea, which he makes it the
sign of, and to which he should keep it steadily annexed during that
present discourse. Where he does not, or cannot do this, he in vain
pretends to clear or distinct ideas: it is plain his are not so; and
therefore there can be expected nothing but obscurity and confusion,
where such terms are made use of which have not such a precise
determination.

  Upon this ground I have thought determined ideas a way of speaking
less liable to mistakes, than clear and distinct: and where men have
got such determined ideas of all that they reason, inquire, or argue
about, they will find a great part of their doubts and disputes at
an end; the greatest part of the questions and controversies that
perplex mankind depending on the doubtful and uncertain use of
words, or (which is the same) indetermined ideas, which they are
made to stand for. I have made choice of these terms to signify, (1)
Some immediate object of the mind, which it perceives and has before
it, distinct from the sound it uses as a sign of it. (2) That this
idea, thus determined, i.e. which the mind has in itself, and knows,
and sees there, be determined without any change to that name, and
that name determined to that precise idea. If men had such
determined ideas in their inquiries and discourses, they would both
discern how far their own inquiries and discourses went, and avoid the
greatest part of the disputes and wranglings they have with others.

  Besides this, the bookseller will think it necessary I should
advertise the reader that there is an addition of two chapters
wholly new; the one of the Association of Ideas, the other of
Enthusiasm. These, with some other larger additions never before
printed, he has engaged to print by themselves, after the same manner,
and for the same purpose, as was done when this Essay had the second
impression.

  In the Sixth Edition there is very little added or altered. The
greatest part of what is new is contained in the twenty-first
chapter of the second book, which any one, if he thinks it worth
while, may, with a very little labour, transcribe into the margin of
the former edition.
INTRODUCTION

                               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.

                             INTRODUCTION

  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.