1. What truth is. What is truth? was an inquiry many ages since; and it being that which all mankind
either do, or pretend to search after, it cannot but be worth our while carefully to examine wherein it
consists, and so acquaint ourselves with the nature of it, as to observe how the mind distinguishes it
from falsehood.
2. A right joining or separating of signs, i.e., either ideas or words. Truth, then, seems to me, in the
proper import of the word, to signify nothing but the joining or separating of Signs, as the Things
signified by them do agree or disagree one with another. The joining or separating of signs here
meant, is what by another name we call proposition. So that truth properly belongs only to
propositions: whereof there are two sorts, viz., mental and verbal; as there are two sorts of signs
commonly made use of, viz., ideas and words.
3. Which make mental or verbal propositions. To form a clear notion of truth, it is very necessary to
consider truth of thought, and truth of words, distinctly one from another: but yet it is very difficult to
treat of them asunder. Because it is unavoidable, in treating of mental propositions, to make use of
words: and then the instances given of mental propositions cease immediately to be barely mental,
and become verbal. For a mental proposition being nothing but a bare consideration of the ideas, as
they are in our minds, stripped of names, they lose the nature of purely mental propositions as soon
as they are put into words.
4. Mental propositions are very hard to he treated of. And that which makes it yet harder to treat of
mental and verbal propositions separately is, that most men, if not all, in their thinking and
reasonings within themselves, make use of words instead of ideas; at least when the subject of their
meditation contains in it complex ideas. Which is a great evidence of the imperfection and
uncertainty of our ideas of that kind, and may, if attentively made use of, serve for a mark to show
us what are those things we have clear and perfect established ideas of, and what not. For if we will
curiously observe the way our mind takes in thinking and reasoning, we shall find, I suppose, that
when we make any propositions within our own thoughts about white or black, sweet or bitter, a
triangle or a circle, we can and often do frame in our minds the ideas themselves, without reflecting
on the names. But when we would consider, or make propositions about the more complex ideas,
as of a man, vitriol, fortitude, glory, we usually put the name for the idea: because the ideas these
names stand for, being for the most part imperfect, confused, and undetermined, we reflect on the
names themselves, because they are more clear, certain, and distinct, and readier occur to our
thoughts than the pure ideas: and so we make use of these words instead of the ideas themselves,
even when we would meditate and reason within ourselves, and make tacit mental propositions. In
substances, as has been already noticed, this is occasioned by the imperfections of our ideas: we
making the name stand for the real essence, of which we have no idea at all. In modes, it is
occasioned by the great number of simple ideas that go to the making them up. For many of them
being compounded, the name occurs much easier than the complex idea itself, which requires time
and attention to be recollected, and exactly represented to the mind, even in those men who have
formerly been at the pains to do it; and is utterly impossible to be done by those who, though they
have ready in their memory the greatest part of the common words of that language, yet perhaps
never troubled themselves in all their lives to consider what precise ideas the most of them stood
for. Some confused or obscure notions have served their turns; and many who talk very much of
religion and conscience, of church and faith, of power and right, of obstructions and humours,
melancholy and choler, would perhaps have little left in their thoughts and meditations if one should
desire them to think only of the things themselves and lay by those words with which they so often
confound others, and not seldom themselves also.
5. Mental and verbal propositions contrasted. But to return to the consideration of truth: we must, I
say, observe two sorts of propositions that we are capable of making:--
First, mental, wherein the ideas in our understandings are without the use of words put together, or
separated, by the mind perceiving or judging of their agreement or disagreement.
Secondly, Verbal propositions, which are words, the signs of our ideas, put together or separated in
affirmative or negative sentences. By which way of affirming or denying, these signs, made by
sounds, are, as it were, put together or separated one from another. So that proposition consists in
joining or separating signs; and truth consists in the putting together or separating those signs,
according as the things which they stand for agree or disagree.
6. When mental propositions contain real truth, and when verbal. Every one's experience will satisfy
him, that the mind, either by perceiving, or supposing, the agreement or disagreement of any of its
ideas, does tacitly within itself put them into a kind of proposition affirmative or negative; which I
have endeavoured to express by the terms putting together and separating. But this action of the
mind, which is so familiar to every thinking and reasoning man, is easier to be conceived by
reflecting on what passes in us when we affirm or deny, than to be explained by words. When a
man has in his head the idea of two lines, viz., the side and diagonal of a square, whereof the
diagonal is an inch long, he may have the idea also of the division of that line into a certain number
of equal parts: v.g. into five, ten, a hundred, a thousand, or any other number, and may have the
idea of that inch line being divisible, or not divisible, into such equal parts, as a certain number of
them will be equal to the sideline. Now, whenever he perceives, believes, or supposes such a kind
of divisibility to agree or disagree to his idea of that line, he, as it were, joins or separates those two
ideas, viz., the idea of that line, and the idea of that kind of divisibility; and so makes a mental
proposition, which is true or false, according as such a kind of divisibility; a divisibility into such
aliquot parts, does really agree to that line or no. When ideas are so put together, or separated in
the mind, as they or the things they stand for do agree or not, that is, as I may call it, mental truth.
But truth of words is something more; and that is the affirming or denying of words one of another,
as the ideas they stand for agree or disagree: and this again is two-fold; either purely verbal and
trifling, which I shall speak of, (chap. viii.,) or real and instructive; which is the object of that real
knowledge which we have spoken of already.
7. Objection against verbal truth, that "thus it may all be chimerical." But here again will be apt to
occur the same doubt about truth, that did about knowledge: and it will be objected, that if truth be
nothing but the joining and separating of words in propositions, as the ideas they stand for agree or
disagree in men's minds, the knowledge of truth is not so valuable a thing as it is taken to be, nor
worth the pains and time men employ in the search of it: since by this account it amounts to no more
than the conformity of words to the chimeras of men's brains. Who knows not what odd notions
many men's heads are filled with, and what strange ideas all men's brains are capable of? But if we
rest here, we know the truth of nothing by this rule, but of the visionary words in our own
imaginations; nor have other truth, but what as much concerns harpies and centaurs, as men and
horses. For those, and the like, may be ideas in our heads, and have their agreement or
disagreement there, as well as the ideas of real beings, and so have as true propositions made
about them. And it will be altogether as true a proposition to say all centaurs are animals, as that all
men are animals; and the certainty of one as great as the other. For in both the propositions, the
words are put together according to the agreement of the ideas in our minds: and the agreement of
the idea of animal with that of centaur is as clear and visible to the mind, as the agreement of the
idea of animal with that of man; and so these two propositions are equally true, equally certain. But
of what use is all such truth to us?
8. Answered, "Real truth is about ideas agreeing to things." Though what has been said in the
foregoing chapter to distinguish real from imaginary knowledge might suffice here, in answer to this
doubt, to distinguish real truth from chimerical, or (if you please) barely nominal, they depending
both on the same foundation; yet it may not be amiss here again to consider, that though our words
signify nothing but our ideas, yet being designed by them to signify things, the truth they contain
when put into propositions will be only verbal, when they stand for ideas in the mind that have not an
agreement with the reality of things. And therefore truth as well as knowledge may well come under
the distinction of verbal and real; that being only verbal truth, wherein terms are joined according to
the agreement or disagreement of the ideas they stand for; without regarding whether our ideas are
such as really have, or are capable of having, an existence in nature. But then it is they contain real
truth, when these signs are joined, as our ideas agree; and when our ideas are such as we know
are capable of having an existence in nature: which in substances we cannot know, but by knowing
that such have existed.
9. Truth and falsehood in general. Truth is the marking down in words the agreement or
disagreement of ideas as it is. Falsehood is the marking down in words the agreement or
disagreement of ideas otherwise than it is. And so far as these ideas, thus marked by sounds, agree
to their archetypes, so far only is the truth real. The knowledge of this truth consists in knowing what
ideas the words stand for, and the perception of the agreement or disagreement of those ideas,
according as it is marked by those words.
10. General propositions to be treated of more at large. But because words are looked on as the
great conduits of truth and knowledge, and that in conveying and receiving of truth, and commonly
in reasoning about it, we make use of words and propositions, I shall more at large inquire wherein
the certainty of real truths contained in propositions consists, and where it is to be had; and
endeavour to show in what sort of universal propositions we are capable of being certain of their real
truth or falsehood.
I shall begin with general propositions, as those which most employ our thoughts, and exercise our
contemplation. General truths are most looked after by the mind as those that most enlarge our
knowledge; and by their comprehensiveness satisfying us at once of many particulars, enlarge our
view, and shorten our way to knowledge.
11. Moral and metaphysical truth. Besides truth taken in the strict sense before mentioned, there are
other sorts of truths: As, 1. Moral truth, which is speaking of things according to the persuasion of
our own minds, though the proposition we speak agree not to the reality of things; 2. Metaphysical
truth, which is nothing but the real existence of things, conformable to the ideas to which we have
annexed their names. This, though it seems to consist in the very beings of things, yet, when
considered a little nearly, will appear to include a tacit proposition, whereby the mind joins that
particular thing to the idea it had before settled with the name to it. But these considerations of truth,
either having been before taken notice of, or not being much to our present purpose, it may suffice
here only to have mentioned them.