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. Falsehood is the joining of names otherwise than their ideas agree. 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 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.

CHAPTER VI.

OF UNIVERSAL PROPOSITIONS, THEIR TRUTH AND CERTAINTY.

1. Treating of words necessary to knowledge.-Though the examining and judging of ideas by themselves, their names being quite laid aside, be the best and 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 is very hard to speak intelligibly of the one without explaining the other.

2. General truths hardly to be understood but in verbal propositions. All the knowledge we have being only of particular or general truths, it is evident that whatever may be done in the former of these, the latter, which is that which with reason is most sought after, 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.

3. Certainty twofold, of truth and of knowledge.-But that we may not be misled in this case by that which is the danger everywhere, I mean by the doubtfulness of terms, it is fit to observe that certainty is twofold; 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."

4. No proposition can be known to be true, where the essence of each species mentioned is not known.-Now, because we cannot be certain of the truth of any general proposition unless we know the precise bounds and extent of the species its terms stand for, it is necessary we should know the essence of each species, which is that which constitutes and bounds it. This, in all simple 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 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 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 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 be true or no. I have chose 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 uncertainty into all general propositions that can be made about them. Though therefore these things might, to people not possessed with scholastic learning, be perhaps treated of in a better and clearer way; yet those wrong notions of essences or species, having got root in most people's minds who have received any tincture from the learning which has prevailed in this part of the world, are to be discovered and removed to make way for that use of words which should convey certainty with it.

5. This more particularly concerns substances.-The names of substances then, whenever made to stand for species which are supposed to be constituted by real essences which we know not, are not capable to convey certainty to the understanding: of the truth of general propositions made up of such terms we cannot be sure. The reason whereof is plain. For, how can we be sure that this or that quality is in gold, when we know not what is or is not gold? since in this way of speaking nothing is gold but what partakes of an essence, which we not knowing cannot know where it is or is not, and so cannot be sure that any parcel of matter in the world is or is not in this sense gold; being incurably ignorant whether it has or has not that which makes any thing to be called "gold," i. e. that real essence of gold whereof we have no idea at all: this being as impossible for us to know, as it is for a blind man to tell in what flower the colour of a pansy is or is not to be found, whilst he has no idea of the colour of a pansy at all. Or if we could (which is impossible) certainly know where a real essence

which we know not, is, v. g. in what parcels of matter the real essence of gold is, yet could we not be sure that this or that quality could with truth be affirmed of gold; since it is impossible for us to know that this or that quality or idea has a necessary connexion with a real essence, of which we have no idea at all, whatever species that supposed real essence may be imagined to constitute.

6. The truth of few universal propositions concerning substances is to be known. On the other side, the names of substances, when made use of, as they should be, for the ideas men have in their minds, though they carry a clear and determined signification with them, will not yet serve us to make many universal propositions, of whose truth we can be certain. Not because in this use of them we are uncertain what things are signified by them, but because the complex ideas they stand for are such combinations of simple ones as carry not with them any discoverable connexion or repugnancy but with a very few other ideas.

7. Because co-existence of ideas in few cases is to be known.—The complex ideas that our names of the species of substances properly stand for, are collections of such qualities as have been observed to co-exist in an unknown substratum which we call "substance;" but what other qualities necessarily co-exist with such combinations, we cannot certainly know, unless we can discover their natural dependence; which in their primary qualities we can go but a very little way in; and in all their secondary qualities we can discover no connexion at all, for the reasons mentioned, (chap. iii.) viz. (1.) Because we know not the real constitutions of substances, on which each secondary quality particularly depends. (2.) Did we know that, it would serve us only for experimental (not universal) knowledge; and reach with certainty no farther than that bare instance; because our understandings can discover no conceivable connexion between any secondary quality, and any modification whatsoever of any of the primary ones. And therefore there are very few general propositions to be made concerning substances which can carry with them undoubted certainty.

8. Instance in gold.—"All gold is fixed," is a proposition whose truth we cannot be certain of, how universally soever it be believed. For if, according to the useless imagination of the Schools, any one supposes the term "gold" to stand for a species of things set out by nature by a real essence belonging to it, it is evident he knows not what particular substances are of that species; and so cannot, with certainty, affirm any thing universally of gold. But if he makes gold stand for a species, determined by its nominal essence, let the nominal essence, for example, be the complex idea of a body, of a certain yellow colour, malleable, fusible, and heavier than any other known; in this proper use of the word "gold," there is no difficulty to know what is or is not gold. But yet no other quality can with certainty be universally affirmed or denied of gold, but what hath a discoverable connexion or inconsistency with that nominal essence. Fixedness, for example, having no necessary connexion that we can discover with the colour, weight, or any

other simple idea of our complex one, or with the whole combination together; it is impossible that we should certainly know the truth of this proposition, that "all gold is fixed."

9. As there is no discoverable connexion between fixedness and the colour, weight, and other simple ideas of that nominal essence of gold; so if we make our complex idea of gold "a body yellow, fusible, ductile, weighty, and fixed," we shall be at the same uncertainty concerning solubility in aqua regia; and for the same reason since we can never, from consideration of the ideas themselves, with certainty affirm or deny of a body, whose complex idea is made up of yellow, very weighty, ductile, fusible, and fixed, that it is soluble in aqua regia: and so on of the rest of its qualities. I would gladly meet with one general affirmation, concerning any quality of gold, that any one can certainly know is true. It will, no doubt, be presently objected, "Is not this an universal certain proposition, All gold is malleable?"" To which I answer, It is a very certain proposition, if malleableness be a part of the complex idea the word "gold" stands for. But then here is nothing affirmed of gold, but that that sound stands for an idea in which malleableness is contained and such a sort of truth and certainty as this it is to say, "A centaur is four-footed." But if malleableness makes not a part of the specific essence the name "gold" stands for, it is plain, "All gold is malleable," is not a certain proposition; because, let the complex idea of gold be made up of which soever of its other qualities you please, malleableness will not appear to depend on that complex idea, nor follow from any simple one contained in it: the connexion that malleableness has (if it has any) with those other qualities being only by the intervention of the real constitution of its insensible parts, which since we know not, it is impossible we should perceive that connexion, unless we could discover that which ties them together.

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10. As far as any such co-existence can be known, so far universal propositions may be certain. But this will go but a little way, because-The more, indeed, of these co-existing qualities we unite into one complex idea, under one name, the more precise and determinate we make the signification of that word; but yet never make it thereby more capable of universal certainty in respect of other qualities not contained in our complex idea; since we perceive not their connexion or dependence one on another, being ignorant both of that real constitution in which they are all founded, and also how they flow from it. For the chief part of our knowledge concerning substances is not, as in other things, barely of the relation of two ideas that may exist separately; but is of the necessary connexion and co-existence of several distinct ideas in the same subject, or of their repugnances so to co-exist. Could we begin at the other end, and discover what it was wherein that colour consisted, what made a body lighter or heavier, what texture of parts made it malleable, fusible, and fixed, and fit to be dissolved in this sort of liquor, and not in another; if (I say) we had such an idea as this of bodies, and could perceive wherein all sensible qualities originally consist, and how they are produced,