 Section 5 of an Essay Concerning Humane Understanding by John Locke, Book 4 of Knowledge and Probability. This is a LibriVox recording. While LibriVox recordings are in the public domain, for more information or to volunteer, please visit LibriVox.org. Chapter 4 of the Reality of Knowledge. 1. Objection. Knowledge placed in our ideas may be all unreal or chimerical. I doubt not but my reader, by this time, may be apt to think that I have been all this while only building a castle in the air and be ready to say to me, to what purpose all this, or knowledge, say you, is only the perception of the agreement or disagreement of our own ideas. But who knows what those ideas may be? Is there anything so extravagant as the imaginations of men's brains? Where is the head that has no chimeras in it? Or if there be a sober and a wise man, what difference will there be by your rules between his knowledge and that of the most extravagant fancy in the world? They both have their ideas and perceive their agreement and disagreement one with another. If there be any difference between them, the advantage will be on the warm-headed man's side as having the more ideas and the more lively, and so, by your rules, he will be the more knowing. If it be true, that all knowledge lies only in the perception of the agreement or disagreement of our own ideas. The visions of an enthusiast and the reasonings of a sober man will be equally certain. It is no matter how things are, so a man observe but the agreement of his own imaginations and talk conformably. It is all truth, all certainty. Such castles in the air will be as strongholds of truth as the demonstration of Euclid, that an harpy is not a centaur is by this way a certain knowledge, and as much a truth as that a square is not a circle. But of what use is all this fine knowledge of men's own imaginations? To a man that inquires after the reality of things, it matters not what men's fancies are. It is the knowledge of things that is only to be prized. It is this alone gives a value to our reasonings and preference to one man's knowledge over another's, that it is of things as they really are, and not of dreams and fancies. To answer not so, where ideas agree with things. To which I answer, that if our knowledge of ideas terminate in them and reach no further, where there is something further intended, our most serious thoughts will be of little more use than the reveries of a crazy brain. And the truths built thereon of no more weight than the discourses of a man who sees things clearly in a dream, and with great assurance utters them. But I hope, before I have done, to make it evident that this way of certainty by the knowledge of our own ideas goes a little further than bare imagination, and I believe it will appear that all the certainty of general truths a man has lies in nothing else. Three. But what shall be the criterion of this agreement? It is evident the mind knows not things immediately, but only by the intervention of the ideas it has of them. Our knowledge, therefore, is real only so far as there is a conformity between our ideas and the reality of things. But what shall be here the criterion? How shall the mind, when it perceives nothing but its own ideas, know that they agree with things themselves? This, though it seems not to want difficulty, yet I think there be two sorts of ideas that we may be assured agree with things. For, as, first all, simple ideas are really conformed to things. First, the first are simple ideas, which, since the mind, as has been showed, can by no means make to itself, must necessarily be the product of things operating on the mind in a natural way, and producing therein those perceptions which, by the wisdom and will of our maker, they are ordained and adapted to. From whence it follows that simple ideas are not fictions of our fancies, but the natural and regular productions of things without us really operating upon us, and so carry with them all the conformity which is intended, or which our state requires, for they represent to us things under those appearances which they are fitted to produce in us, whereby we are enabled to distinguish the sorts of particular substances to discern the states they are in, and so to take them for our necessities and apply them to our uses. Thus the idea of whiteness or bitterness, as it is in the mind, exactly answering that power which is in anybody to produce it there, has all the real conformity it can or ought to have with things without us, and this conformity between our simple ideas and the existence of things is sufficient for real knowledge. 5. Secondly, all complex ideas, except ideas of substances, are their own archetypes. Secondly, all our complex ideas, except those of substances, being archetypes of the mind's own making, not intended to be the copies of anything nor referred to the existence of anything as to their originals, cannot want any conformity necessary to real knowledge, for that which is not designed to represent anything but itself, can never be capable of a wrong representation nor mislead us from the true apprehension of anything by its dislikeness to it. 6. And such, accepting those of substances, are all our complex ideas, which, as I have showed in another place, are combinations of ideas which the mind, by its free choice, puts together without considering any connection they have in nature. 7. And hence it is, that in all these sorts the ideas themselves are considered as the archetypes and things no otherwise regarded, as they are conformable to them, so that we cannot but be infallibly certain that all the knowledge we attain concerning these ideas is real and reaches things themselves, because in all our thoughts, reasonings, and discourses of this kind, we intend things no further than as they are conformable to our ideas, so that in these we cannot miss of a certain and undoubted reality. 6. Hence the reality of mathematical knowledge. I doubt not, but it will be easily granted, that the knowledge we have of mathematical truths is not only certain, but real knowledge, and not the bare empty vision of any insignificant chimeras of the brain, and yet, if we will consider, we shall find that it is only of our own ideas. The mathematician considers the truth and properties belonging to a rectangle or circle only as they are in idea in his own mind, for it is possible he never found either of them existing mathematically, for instance, precisely true in his life, but yet the knowledge he has of any truths or properties belonging to a circle or any mathematical figure are nevertheless true and certain, even of real things existing, because real things are no further concerned nor intended to be meant by any such propositions, then as things really agree to those archetypes in his true mind, is it true of the idea of a triangle that its three angles are equal to two bright ones? It is true also of a triangle wherever it really exists. Whatever other figure exists, that it is not exactly answerable to that idea of a triangle in his mind, is not at all concerned in that proposition, and therefore he is certain all his knowledge concerning such ideas is real knowledge, because, intending things no further than they agree with those his ideas, he is sure what he knows concerning those figures, when they are barely an ideal existence in his mind, will hold true of them also when they have a real existence in matter. His consideration being barely of those figures, which are the same wherever or however they exist. Seven, and of moral, and hence it follows that moral knowledge is as capable of real certainty as mathematics, for certainty being but the perception of the agreement or disagreement of our ideas, and demonstration nothing but the perception of such agreement by the intervention of other ideas or mediums. There are moral ideas as well as mathematical, being archetypes themselves and so adequate and complete ideas. All the agreement or disagreement which we shall find in them will produce real knowledge, as well as in mathematical figures. Eight, existence not required to make abstract knowledge real. For the attaining of knowledge and certainty it is requisite that we have determined ideas, and, to make our knowledge real, it is requisite that the ideas answer their archtypes, nor let it be wondered that I place the certainty of our knowledge in the consideration of our ideas, with so little care in regard, as it may seem, to the real existence of things, since most of those discourses which take up the thoughts and engage the disputes of those who pretend to make it their business to inquire after truth and certainty will, I presume, upon examination be found to be general propositions and notions in which existence is not at all concerned. All the discourses of the mathematicians about the squaring of a circle, conic sections, or any other part of mathematics concern not the existence of any of those figures, but their demonstrations, which depend on their ideas, are the same, whether there be any square or circle existing in the world or no. In the same manner the truth and certainty of moral discourses abstracts from the lives of men, and the existence of those virtues in the world whereof they treat, nor are Tully's offices less true, because there is nobody in the world that exactly practices his rules, and lives up to that pattern of a virtuous man which he has given us, and which existed nowhere when he writ but in idea, if it be true in speculation, for instance, in idea, that murder deserves death. It will also be true in reality of any action that exists conformable to that idea of murder, as for other actions the truth of that proposition concerns them not, and thus it is of all other species of things which have no other essences, but those ideas which are in the minds of men. 9. Nor will it be less true or certain, because moral ideas are of our own making and naming, but it will here be said that if moral knowledge be placed in the contemplation of our own moral ideas, and those, as other modes, be of our own making, what strange notions will there be of justice and temperance? What confusion of virtues and vices? If everyone may make what ideas of them he pleases. 9. No confusion or disorder in the things themselves, nor the reasonings about them, no more than in mathematics there would be a disturbance in the demonstration, or a change in the properties of figures, and their relations one to another, if a man should make a triangle with four corners, or a trapezium with four right angles, that is, in plain English, change the names of the figures and call that by one name, which mathematicians call ordinarily by another, for let a man make to himself the idea of a figure with three angles, whereof one is a right one, and call it, if he please, equilaterum or trapezium, or anything else. The properties of and demonstrations about that idea will be the same as if he called it a rectangular triangle. I confess the change of the name by the impropriety of speech will at first disturb him who knows not what idea it stands for. But as soon as the figure is drawn, the consequences and demonstration are plain and clear. Just the same is it in moral knowledge that a man have the idea of taking from others without their consent, what their honest industry has possessed them of, and call this justice if he please. He that takes the name here without the idea put to it will be mistaken by joining another idea of his own to that name, but strip the idea of that name, or take it such as it is in the speaker's mind, and the same things will agree to it, as if you called it injustice. Indeed, wrong names in moral discourses breed usually more disorder, because they are not so easily rectified as in mathematics, where the figure, once drawn and seen, makes the name useless and of no force, for what need of a sign when the thing signified is present and in view. But in moral names, that cannot be so easily and shortly done, because of the many decompositions that go to the making up the complex ideas of those modes. But yet, for all this, the miscalling of any of those ideas, contrary to the usual signification of the words of that language, hinders not, but that we may have certain and demonstrative knowledge of their several agreements and disagreements. If we will carefully, as in mathematics, keep to the same precise ideas, and trace them in their several relations one to another without being led away by their names, if we but separate the idea under consideration from the sign that stands for it, our knowledge goes equally on in the discovery of real truth and certainty, whatever sounds we make use of. 10. Misnaming disturbs not the certainty of the knowledge. One thing more we are to take notice of, that where God or any other lawmaker hath defined any moral names, there they have made the essence of that species to which that name belongs, and there it is not safe to apply or use them otherwise, but in other cases it is bare impropriety of speech to apply them contrary to the common usage of the country. But yet even this too disturbs not the certainty of that knowledge, which is still to be had by a due contemplation and comparing of those even nicknamed ideas. 11. Thirdly, our complex ideas of substances have their archtypes without us and here knowledge comes short. 13. Thirdly, there is another sort of complex ideas which, being referred to archtypes without us, may differ from them, and so our knowledge about them may come short of being real, such are our ideas of substances which, consisting of a collection of simple ideas, supposed taken from the works of nature, may yet vary from them, by having more or different ideas united in them than are to be found, united in the things themselves, from whence it comes to past, that they may, and often do, fail of being exactly conformable to things themselves. 12. So far as our complex ideas agree with those archtypes without us, so far our knowledge concerning substances is real, I say, then, that to have ideas of substances which, by being conformable to things, may afford us real knowledge, it is not enough, as in modes, to put together such ideas as have no inconsistence, though they did never before so exist, for instance, the ideas of sacrilege or perjury, etc. were as real and true ideas before, as after the existence of any such fact, but our ideas of substances being supposed copies, and referred to archtypes without us, must still be taken from something that does or has existed, they must not consist of ideas put together at the pleasure of our thoughts, without any real pattern they were taken from. 13. So we can perceive no inconsistence in such a combination. The reason we are of is because we, knowing not what real constitution it is of substances, whereon our simple ideas depend, and which really is the cause of the strict union of some of them, one with another, and the exclusion of others. There are very few of them that we can be sure are, not inconsistent in nature, any further than experience and sensible observation reach. Herein, therefore, is found at the reality of our knowledge concerning substances, that all our complex ideas of them must be such, and such only, as are made up of such simple ones as have been discovered to coexist in nature. And our ideas being thus true, though not perhaps very exact copies, are yet the subjects of real, as far as we have any knowledge of them, which, as has been already shown, will not be found to reach very far. But so far as it does, it will still be real knowledge, whatever ideas we have. The agreement we find they have with others will still be knowledge. If those ideas be abstract, it will be general knowledge, but to make it real concerning substances, the ideas must be taken from the real existence of things. Whatever simple ideas have been found to coexist in any substance, these we may, with confidence, join together again, and so make abstract ideas of substances, for whatever have once had an union in nature may be united again. 13. In our inquiries about substances, we must consider ideas, and not confine our thoughts to names, or species supposed set out by names. This, if we rightly consider, and confine not our thoughts and abstract ideas to names, as if they were, or could be no other sorts of things than what known names had already determined. And, as it were, set out, we should think of things with greater freedom and less confusion than perhaps we do. It would possibly be thought a bold paradox, if not a very dangerous falsehood. If I should say that some changelings, who have lived forty years together, without any appearance of reason, are something between a man and a beast, which prejudice is found upon nothing else but a false supposition, that these two names, man and beast, stand for distinct species so set out by real essences, that there can come no other species between them, whereas if we will abstract from those names, and the supposition of such specific essences made by nature, wherein all things of the same denominations did exactly and equally partake, if we would not fancy that there were a certain number of these essences, wherein all things, as in molds, were cast and formed, we should find that the idea of the shape, motion, and life of a man without reason, in as much a distinct idea, and makes as much a distinct sort of things from man and beast, as the idea of the shape of an ass with reason would be different from either that of man or beast, and be a species of an animal between, or distinct from both. 14. Objection against a changeling being something between a man and beast, answered. Here everybody will be ready to ask, if changelings may be supposed something between man and beast, pray what are they? I answer, changelings, which is as good a word to signify something different from the signification of man or beast, as the names man and beast are to have significations different one from the other. This, well considered, would resolve this matter, and show by meaning without any more ado. But I am not so unacquainted with the zeal of some men, which enables them to spin consequences, and to see religion threatened whenever anyone ventures to quit their forms of speaking, as not to foresee what names such a proposition as this is like to be charged with. And without doubt it will be asked, if changelings are something between man and beast, what will become of them in the other world? To which I answer, I. It concerns me not to know or inquire, to their own master they stand or fall. It will make their state neither better nor worse, whether we determine anything of it or know. They are in the hands of a faithful creator and a bountiful father who disposes not of his creatures according to our narrow thoughts or opinions, nor distinguishes them according to names and species of our contrivance. And we that know so little of this present world we are in may, I think, content ourselves without being peremptory in defining the different states which each creature shall come into when they go off this stage. It may suffice us that he hath made known to all those who are capable of instruction, discoursing and reasoning, that they shall come to an account and receive according to what they have done in this body. 15. What will become of changelings in a future state? But, secondly, I answer, the force of these men's question, namely, will you deprive changelings of a future state, is founded on one of these two suppositions, which are both false. The first is that all things that have the outward shape and appearance of a man must necessarily be designed to an immortal future being after this life. Or, secondly, that whatever is of human birth must be so. Take away these imaginations, and such questions will be groundless and ridiculous. I desire then those who think there is no more but an accidental difference between themselves and changelings. The essence in both being exactly the same, to consider whether they can imagine immortality annexed to any outward shape of the body, the very proposing it is, I suppose, enough to make them disown it. No one yet, that ever I heard of, how much so ever immersed in matter, allowed that excellency to any figure of the gross sensible outward consequence of it, or that any mass of matter should, after its dissolution here, be again restored hereafter to an everlasting state of sense, perception, and knowledge, only because it was molded into this or that figure, and had such a particular frame of its visible parts. Such an opinion is this, placing immortality in a certain superficial figure, turns out of doors all consideration of soul or spirit, upon whose account alone some corporal beings have hitherto been concluded immortal and others not. This is to attribute more to the outside than inside of things, and to place the excellency of a man more in the external shape of his body than internal perfections of his soul, which is but little better than to annex the great and inestimable advantage of immortality and life everlasting, which he has above other material beings to annex it, I say, to the cut of his beard, or the fashion of his coat. For this or that outward mark of our bodies no more carries with it the hope of an eternal duration than the fashion of a man's suit gives him reasonable grounds to imagine it will never wear out, or that it will make him immortal. It will perhaps be said that nobody thinks that the shape makes anything immortal, but it is the shape that is the sign of a rational soul within which is immortal. I wonder who made it the sign of any such thing, for barely saying it will not make it soul. It would require some proofs to persuade one of it. No figure that I know speaks any such language, for it may as rationally be concluded that the dead body of a man wherein there is to be found no more appearance or action of life than there is in a statue has yet nevertheless a living soul in it because of its shape, as that there is a rational soul in a changeling because he has the outside of a rational creature when his actions carry far less marks of reason with them in the whole course of his life than what are to be found in many a beast, sixteen monsters, but it is the issue of rational parents and must therefore be concluded to I know not by what logic you must all conclude. I am sure this is a conclusion that men know where allow of, for if they did they would not make bold, as everywhere they do to destroy ill-formed and misshaped productions. I, but these are monsters. Let them be so. What will your driveling, unintelligent, intractable changeling be? Shall a defect in the body make a monster, a defect in the mind, the far more noble and in the common phrase the far more essential part, not? Shall the want of a nose or a neck make a monster and put such issue out of the rank of men? The want of reason and understanding, not? This is to bring all back again to what was exploded just now. This is to place all in the shape and to take the measure of a man only by his outside. To show that according to the ordinary way of reasoning in this matter, people do lay the whole stress on the figure and resolve the whole essence of the species of man as they make it into the outward shape. How unreasonable so ever it be and how much so ever they disown it. We need but trace their thoughts and practice a little further and then it will plainly appear. The well-shaped changeling is a man has a rational soul, though it appear not. This is past doubt, say you. Make the ears a little longer and more pointed and the nose a little flatter than ordinary. And then you begin to boggle, make the face get narrower, flatter and longer and then you are at a stand. Add still more and more of the likeness of a brute to it and let the head be perfectly that of some other animal, then presently it is a monster and it is demonstration with you that it hath no rational soul and must be destroyed where now I ask shall be the just measure which the utmost bounds of that shape that carries with it a rational soul for since there have been human fetuses produced half beast and half man and others three parts one and one part the other and so it is possible they may be in all the variety of approaches to the one or the other shape and may have several degrees of mixture of the likeness of a man or a brute. I would gladly know what are those precise lineaments which according to this hypothesis are or are not capable of a rational soul to be joined to them. What sort of outside is the certain sign that there is or is not such an inhabitant within for till that be done we talk at random of man and shall always I fear to do so as long as we give ourselves up to certain sounds and the imaginations of settled and fixed species in nature we know not what but after all I desire it may be considered that those who think they have answered the difficulty by telling us that a misshaped fetus is a monster run into the same fault they are arguing against by constituting a species between man and beast for what else I pray is their monster in the case if the word monster signifies anything at all but something neither man nor beast but partaking somewhat of either and just so is the changeling before mentioned so necessary is it to quit the common notion of species and essences if we will truly look into the nature of things and examine them by what our faculties can discover in them as they exist and not by groundless fancies that have been taken up about them seventeen words and species I have mentioned this here because I think we cannot be too cautious that words and species in the ordinary notions which we have been used to of them impose not on us for I am apt to think therein lies one great obstacle to our clear and distinct knowledge especially in reference to substances and from thence has rose a great part of the difficulties about truth and certainty would we a custom ourselves to separate our contemplations and reasonings from words we might in a great measure remedy this inconvenience within our own thoughts but yet it would still to serve us in our discourse with others as long as we retained the opinion that species and their essences were anything else but our abstract ideas such as they are with names and next to them to be the signs of them eighteen recapitulation wherever we perceive the agreement or disagreement of any of our ideas there is certain knowledge and wherever we are sure those ideas agree with the reality of things there is certain real knowledge of which agreement of our ideas with the reality of things having here given the marks I think I have shown where in it is that certainty real certainty consists which whatever it was to others was I confess to me here to for one of those desiderata which I found great want of end of section five section six of an essay concerning humane understanding by John Locke book four of knowledge and probability this is a LibriVox recording all LibriVox recordings are in the public domain for more information or to volunteer please visit LibriVox.org chapter five of truth in general one 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 where in it consists and so acquaintance ourselves with the nature of it as to observe how the mind distinguishes it from falsehood to 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 was another the joining or separation of signs here meant is what by another name we call proposition so that truth properly belongs only to propositions where of there are two sorts this mental and verbal as there are two sorts of signs commonly made use of this ideas and words three which make mental or verbal propositions to form a clear notion of truth it is either truth of thought and truth of words distinctly one from another but yet it is very difficult to treat of them as under because it is unavoidable in treating of mental propositions to make use of words and then the instances given of mental propositions sees immediately to be barely mental and become verbal for a mental proposition being nothing but the 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 for mental propositions are very hard to be treated of and that which makes it yet harder to treat mental and verbal propositions separately is that most men if not all in 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 ideas of and what not for if we will curiously observe the way our mind takes in thinking and reasoning we shall find a 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 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 ready or a cure to our thoughts and 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 tested 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 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 a cures 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 it is certainly 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 trouble 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 color 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 can found others and not sell them themselves also five 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 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 from another so that proposition consists in joining or separating signs and truth consists in deputing together or separating those signs according as the things which they stand for, agree or disagree six when mental propositions contain real truth and when verbal everyone'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 puts them into a kind of proposition which I have endeavored 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 vij into 5, 10, 100, 1000 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 side line 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 into such eloquent 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, chapter 8 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 chemical but here again will be apt to or the same doubt about truth that did about knowledge and it will be objected that if truth be nothing but the joining and separating words and 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 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 truths but what as much concerns 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 truths to us 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 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 where in 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 conduit 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 truth 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 a strict sense before mentioned there are other sorts of truth as one 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 two 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 End of Section 6 of universal propositions their truth and certainty one 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 practiced everyone 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 two 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 three, 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 four, no proposition can be certainly known to be true where the real 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 where in 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 further 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 proposition be true or not 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 then barely abstract ideas with names to them to suppose that the species of things are anything but the sorting of them under general names according as they agree to several abstract ideas of which we make those names signs is to confound truth and introduce uncertainty into all general propositions that can be made about them though therefore these things might be not possessed with scholastic learning be 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 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 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 anything 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 color of a pansy is or is not to be found whilst he has no idea of the color 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 connection with a real essence of which we have no idea at all whatever species that supposed real essence may be imagined to constitute six 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 determinant 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 connection or repugnancy but with a very few other ideas seven the complex ideas that our names of the species of substances properly stand for are collections of such qualities as have been observed to coexist in an unknown substratum which we call substance but what other qualities necessarily coexist 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 connection at all for the reasons mentioned chapter three these one because we know not the real constitutions of substances on which each secondary quality particularly depends two, did we know that it would serve us only for experimental not universal knowledge and reach with certainty no further than that bare instance because our understandings can discover no conceivable connection 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 eight instance in gold all gold is fixed is a proposition whose truth we cannot be certain of how universally so ever it be believed for if according to the useless imagination of the schools anyone 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 anything 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 color 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 have a discoverable connection or inconsistency with that nominal essence fixedness for example having no necessary connection that we can discover with the color 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 nine no discoverable necessary connection between nominal essence gold and other simple ideas as there is no discoverable connection between fixedness and the color 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 will no doubt be presently objected is not this an universal proposition all gold is malleable to which I answer it is a very 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 forefooted but if malleableness make not a part of the specific essence the name of 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 so ever 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 connection 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 connection unless we could discover that which ties them together ten as far as any such coexistence can be known so far universal propositions go but a little way the more indeed of these coexisting qualities we unite into one complex idea under one name the more precise and determinate we make the signification of that word but never yet make it thereby more capable of universal certainty in respect of other qualities not contained in our complex idea since we perceive not their connection or dependence on one 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 connection and coexistence of several distinct ideas in the same subject or of their repugnancy so to coexist could we begin at the other end and discover what it was wherein that color 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 another if I say we had such an idea as this of bodies we could perceive wherein all sensible qualities originally consist and how they are produced we might frame such abstract ideas of them as would furnish us with matter of more general knowledge and enable us to make universal propositions that should carry general truth and certainty with them but whilst our complex ideas of the sorts of substances are so remote from that internal real constitution on which their sensible qualities depend and are made up of nothing but an imperfect collection of those apparent qualities our senses can discover there can be few general propositions concerning substances of whose real truth we can be certainly assured since there are but few simple ideas of whose connection and necessary coexistence we can have certain and undoubted knowledge I imagine amongst all the secondary qualities of substances and the powers relating to them but not any to be named whose necessary coexistence or repugnance to coexist can certainly be known unless in those of the same sense which necessarily exclude one another as I have elsewhere showed no one I think by the color that is in any body can certainly know what smell taste sound or tangible qualities it has nor what alterations it is capable to make or receive on or from other bodies the same may be said of the sound or taste etc our specific names of substances standing for any collections of such ideas it is not to be wondered that we can with them make very few general propositions of undoubted real certainty but yet so far as any complex idea of any sort of substances contains in it any simple idea whose necessary coexistence with any other may be discovered so far universal propositions may with certainty be made concerning it VG could anyone discover necessary connection between malleableness and the color or weight of gold or any other part of the complex idea signified by that name he might make a certain universal proposition concerning gold in this respect and the real truth of this proposition that all gold is malleable would be as certain as of this the three angles of all right lined triangles are all equal to two right ones 11. the qualities which make our complex ideas of substances depend mostly on external remote and unperceived causes had we such ideas of substances as to know what real constitutions produce those sensible qualities we find in them and how those qualities flowed from thence we could by the specific ideas of their real essences in our own minds more certainly find out their properties and discover what qualities they had or had not than we can now by our senses and to know the properties of gold it would be no more necessary that gold should exist and that we should make experiments upon it than it is necessary for the knowing the properties of a triangle that a triangle should exist in any matter the idea in our minds would serve for the one as well as the other but we are so far from being admitted into the secrets of nature that we scarce so much as ever approach the first entrance towards them for we are want to consider the substances we meet with each of them as an entire thing by itself having all its qualities in itself and independent of other things overlooking for the most part the operations of those invisible fluids they are encompassed with and upon whose motions and operations depend the greatest part of those qualities which are taken notice of in them and are made by us the inherent marks of distinction whereby we know and denominate them put a piece of gold anywhere by itself separate from the reach and influence of all other bodies it will immediately lose all its color and weight and perhaps malleableness too which for odd I know would be changed into a perfect fiability water in which to us fluidity is an essential quality left to itself would cease to be fluid but if inanimate bodies owe so much of their present state to other bodies without them that they would not be what they appear to us were those bodies that environed them removed it is yet more so in vegetables which are nourished, grow and produce leaves flowers and seeds in a constant succession and if we look a little nearer into the state of animals we shall find that their dependence as to life, motion and the most considerable qualities to be observed in them is so holy on extrinsical causes and qualities of other bodies that make no part of them that they cannot subsist a moment without them though yet those bodies on which they depend are little taken notice of and make no part of the complex idea we frame of those animals take the air but for a minute from the greatest part of living creatures and they presently lose sense, life and motion this the necessity of breathing has forced into our knowledge but how many other extrinsical and possibly very remote bodies do the springs of these admirable machines depend on which are not vulgarly observed or so much as thought on and how many are there which the severest inquiry can never discover the inhabitants of this spot of the universe though removed so many millions of miles from the sun yet depend so much on the duly tempered motion of particles coming from or agitated by it that were this earth removed but a small part of the distance out of its present situation and placed a little further or nearer that source of heat it is more than probable that the greatest part of the animals in it would immediately perish since we find them so often destroyed by an excess or defect of the sun's warmth which an accidental position in some parts of this our little globe exposes them to the qualities observed in a lodestone must needs have their source far beyond the confines of that body and the ravage made often on several sorts of animals by invisible causes the certain death as we are told of some of them by barely passing the line or as it is certain of other by being removed into a neighboring country evidently show that the concurrence and operations of several bodies with which they are seldom thought to have anything to do is absolutely necessary to make them be what they appear to us and to preserve those qualities by which we know and distinguish them we are then quite out of the way when we think that things contain within themselves the qualities that appear to us in them and we in vain search for that constitution within the body of a fly or an elephant upon which depend those qualities and powers we observe in them for which perhaps to understand them right we ought to look not only beyond this our earth and atmosphere but even beyond the sun or remotest star our eyes have yet discovered or how much the being and operation of particular substances in this our globe depends on causes utterly beyond our view is impossible for us to determine we see and perceive some of the motions and grosser operations of things here about us but whence the streams come that keep all these curious machines in motion and repair how conveyed and modified is beyond our notice and apprehension and the great parts and wheels as I may so say of this stupendous structure of the universe may for ought we know have such a connection and dependence in their influence and operations one upon another that perhaps things in this our mansion would put on quite another face and cease to be what they are if some one of the stars or great bodies incomprehensibly remote from us should cease to be or move as it does this is certain things however absolute and entire they seem in themselves are but retainers to other parts of nature for that which they are most taken notice of by us their observable qualities actions and powers are owing to something without them and there is not so complete and perfect a part that we know of nature which does not owe the being it has and the excellence of it to its neighbors and we must not confine our thoughts within the surface of any body but look a great deal further to comprehend perfectly those qualities that are in it 12. our nominal essences of substances furnish few universal propositions about them that are certain if this be so it is not to be wondered that we have very imperfect ideas of substances the real essences on which depend their properties and operations are unknown to us we cannot discover so much as that size figure and texture of their minute and active parts which is really in much less the different motions and impulses made in and upon them by bodies from without upon which depends and by which is formed the greatest and most remarkable part of those qualities we observe in them and of which our complex ideas of them are made up this consideration alone is enough to put an end to all our hopes of ever having the ideas of their real essences which whilst we want the nominal essences we make use of instead of them we'll be able to furnish us but very sparingly with any general knowledge or universal propositions capable of real certainty 13. judgment of probability concerning substances may reach further but that is not knowledge we are not therefore to wonder if certainty be to be found in very few general propositions made concerning substances our knowledge of their qualities and properties goes very seldom further than our senses reach and inform us possibly inquisitive and observing men may by strength of judgment penetrate further and on probabilities taken from wary observation and hints well laid together often guess right at what experience has not yet discovered to them but this is but guessing still it amounts only to opinion and has not that certainty which is requisite to knowledge for all general knowledge lies only in our own thoughts and consists barely in the contemplation of our own abstract ideas whenever we perceive any agreement or disagreement amongst them there we have general knowledge and by putting the names of those ideas together accordingly in propositions can with certainty pronounce general truths but because the abstract ideas of substances for which their specific names stand whenever they have any distinct and determinant signification have a discoverable connection or inconsistency with but a very few other ideas the certainty of universal propositions concerning substances is very narrow and scanty in that part which is our principal inquiry concerning them and there are scarce any of the names of substances let the idea it is applied to be what it will of which we can generally and with certainty pronounce that it has or has not this or that other quality belonging to it and constantly coexisting or inconsistent with that idea wherever it is to be found 14 what is requisite for our knowledge of substances before we can have any tolerable knowledge of this kind we must first know what changes the primary qualities of one body do regularly produce in the primary qualities of another and how secondly we must know what primary qualities of any body produce certain sensations or ideas in us this is in truth no less than to know all the effects of matter under its diverse modifications of bulk figure cohesion of parts motion and rest which I think everybody will allow is utterly impossible to be known by us without revelation nor if it were revealed to us what sort of figure bulk and motion of corpuscles would produce in us the sensation of a yellow color and what sort of figure bulk and texture of parts in the super fishies of anybody were fit to give such corpuscles their due motion to produce that color would that be enough to make universal propositions with certainty concerning the several sorts of them unless we had faculties acute enough to perceive the precise bulk figure texture and motion of bodies in those minute parts by which they operate on our senses so that we might buy those frame our abstract ideas of them I have mentioned here only corporeal substances whose operations seem to lie more level to our understandings for as to the operations of spirits both their thinking and moving of bodies we at first sight find ourselves at a loss though perhaps when we have applied our thoughts a little nearer to the consideration of bodies and their operations and examine how far our notions even in these reach with any clearness beyond sensible matter of fact we shall be bound to confess that even in these two our discoveries amount to very little beyond perfect ignorance and incapacity fifteen whilst our complex ideas of substances contain no ideas of their real constitutions we can make but few general propositions concerning them this is evident the abstract complex ideas of substances for which their general names stand not comprehending their real constitutions can afford us very little universal certainty because our ideas of them are not made up of that on which those qualities we observe in them and would inform ourselves about do depend with which they have any certain connection VG let the ideas to which we give the name man be as it commonly is a body of the ordinary shape with sense, voluntary motion and reason joined to it this being the abstract idea and consequently the essence of our species we can make but very few general certain propositions concerning man standing for such an idea because not knowing the real constitution on which sensation, power of motion and reasoning with that particular shape depend and whereby they are united together in the same subject there are very few other qualities with which we can perceive them to have a necessary connection and therefore we cannot with certainty affirm that all men sleep by intervals that no man can be nourished by wood or stones that all men will be poisoned by hemlock because these ideas have no connection nor repugnancy with this our nominal essence of man with this abstract idea that name stands for we must in these and the like appeal to trial in particular subjects which can reach but a little way we must content ourselves with probability in the rest but can have no general certainty whilst our specific idea of man contains not that real constitution which is the root where in all his inseparable qualities are united and from whence they flow whilst our idea the word man stands for is only an imperfect collection of some sensible qualities and powers in him there is no discernible connection or repugnance between our specific idea and the operation of either the parts of hemlock or stones upon his constitution there are animals that safely eat hemlock and others that are nourished by wood and stones but as long as we want ideas of those real constitutions of different sorts of animals where on these and the like qualities and powers depend we must not hope to reach certainty in universal propositions concerning them those few ideas only which have a discernible connection with our nominal essence or any part of it can afford us such propositions but these are so few and of so little moment that we may justly look on our certain general knowledge of substances as almost none at all 16. Where in lies the general certainty of propositions to conclude general propositions of what kind so ever are then only capable of certainty when the terms used in them stand for such ideas whose agreement or disagreement as there expressed is capable to be discovered by us and we are then certain of their truth or falsehood when we perceive the ideas the terms stand for to agree or not agree according as they are affirmed or denied one of another whence we may take notice that general certainty is never to be found but in our ideas whenever we go to seek it elsewhere or experiment or observations without us our knowledge goes not beyond particulars it is the contemplation of our own abstract ideas that alone is able to afford us general knowledge End of section 7