« السابقةمتابعة »
about knowledge: and it will be objected, bal truthi, that if truth be nothing but the joining
that thus it
all be and separating of words in propositions, chimerical. 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 and 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. Though what has been said in the
Answered, foregoing chapter, to distinguish real from real truth is imaginary knowledge, might suffice here, about ideas in-answer to this doubt, to distinguish agreeing to real truth from chimerical, or (if you
things. 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 propo
sitions, 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 is the marking down in words Falsehood is the joining
the agreement or disagreement of ideas of names
as it is. Falsehood is the marking down otherwise in words the agreement or disagreement than their
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. General
§ 10. But because words are looked on propositions
as the great conduits of truth and knowto be treated of more at
ledge, and that in conveying and receiving large. of truth, and commonly in reasoning about it, we make use of words and propositions ; 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. i § 11. Besides truth taken in the strict Moral and sense before-mentioned, there are other metaphy, sorts of truth; as, 1. Moral truth, which is sical truth. 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 a 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.
Of Universal Propositions, their Truth and Certainty:
$ 1. Though the examining and judg- Treating of ing of ideas by themselves, their names
words nebeing quite laid asidè, be the best and cessary to
knowledge. surest way to clear and distinct knowledge; yet, through the prevailing custom of using sounds for ideas, I think it is very
seldom practised. Every one may observe how common it is for names to be made use of, instead of the ideas themselves, even when men think and reason within their own breasts; especially if the ideas be very complex, and made
up of a great collection of simple ones. This makes the consideration of words and propositions so necessary a part of the treatise of knowledge, that it
very hard to speak intelligibly of the one without explaining the other. General § 2. All the knowledge we have, being truths
only of particular or general truths, it is hardly to be evident that whatever may be done in the anderstood, but in ver
former of these, the latter, which is that bal proposi- which with reason is most sought after, tions.
can never be well made known, and is very seldom apprehended, but as conceived and expressed in words. It is not therefore out of our way, in the examination of our knowledge, to inquire into the truth and certainty of universal propositions. Certainty
§ 3. But that we may not be misled in two-fold, of this case, by that which is the danger truth and of every where, I mean by the doubtfulness knowledge.
of terms, it is fit to observe, that certainty is two-fold; certainty of truth, and certainty of knowledge. Certainty of truth is, when words are so put together in propositions, as exactly to express the agreement or disagreement of the ideas they stand for, as really it is. Certainty of knowledge is to perceive the agreement or disagreement of ideas, as expressed in any proposition. This we usually call knowing, or being certain of the truth of any proposition. No proposi
$ 4. Now because we cannot be certain tion can be of the truth of any general proposition, known to be unless we know the precise bounds and true, where
extent of the species its terms stand for, of each it is necessary we should know the essence species men- of each species, which is that which con
stitutes and bounds it. This, in all simple known.
ideas and modes, is not hard to do. For in these, the real and nominal essence being the same; or, which is all one, the abstract idea which the general term stands for being the sole essence and boundary that is or can be supposed of the species; there can be no doubt, how far the species extends, or what things are comprehended under each term: which, it
tioned is not
is evident, are all that have an exact conformity with the idea it stands for, and no other. But in substances wherein a real essence distinct from the nominal is supposed to constitute, determine, and bound the species, the extent of the general word is very uncertain : because not knowing this real essence, we cannot know what is, or what is not of that species ; and consequently what may, or may not with certainty be affirmed of it. And thus speaking of a man, or gold, or any other species of natural substances, as supposed constituted by a precise and real essence, which nature regularly imparts to every individual of that kind, whereby it is made to be of that species, we cannot be certain of the truth of any affirmation or negation made of it. For man, or gold, taken in this sense, and used for species of things constituted by real essences, different from the complex idea in the mind of the speaker, stand for we know not what; and the extent of these species, with such boundaries, are so unknown and undetermined, that it is impossible with any certainty to affirm, that all men are rational, or that all gold is yellow, But where the nominal essence is kept to, as the boundary of each species, and men extend the application of any general term no farther than to the particular things in which the complex idea it stands for is to be found, there they are in no danger to mistake the bounds of each species, nor can be in doubt, on this account, whether any propositions bé true or no. I have chosen to explain this uncertainty of propositions in this scholastic way, and have made use of the terms of essences and species, on purpose to show the absurdity and inconvenience there is to think of them as of any other sort of realities than barely abstract ideas with names to them. To suppose that the species of things are any thing but the sorting of them under general names, according as they agree to several abstract ideas, of which we make those names the signs, is to confound truth, and introduce