An essay concerning human understanding
by John Locke
Table of Contents
Letter to the Right Honorable Lord Thomas, et al.
Epistle to the Reader 6th Edition
Book I - Neither Principle nor Ideas are Inate
Chapter 01 No Innate Speculative Principles
Chapter 02 No Innate Practical Principles
Chapter 03 Other considerations concerning Innate Principles, both Speculative and Practical
Book II - Of Ideas
Chapter 01 Of Ideas in general, and their Original
Chapter 02 Of Simple Ideas
Chapter 03 Of Simple Ideas of Sense
Chapter 04 Ideas of Solidity
Chapter 05 Of Simple Ideas of Divers Senses
Chapter 06 Of Simple Ideas of Reflection
Chapter 07 Of Simple Ideas of both Sensation and Reflection
Chapter 08 Some further considerations concerning our Simple Ideas of Sensation
Chapter 09 Of Perception
Chapter 10 Of Retention
Chapter 11 Of Discerning, and other operations of the Mind
Chapter 12 Of Complex Ideas
Chapter 13 Complex Ideas of Simple Modes : - and First, of the Simple Modes of the Idea of Space
Chapter 14 Idea of Duration and its Simple Mode
Chapter 15 Ideas of Duration and Expansion, considered together
Chapter 16 Idea of Number
Chapter 17 Of Infinity
Chapter 18 Other Simple Modes
Chapter 19 Of the Modes of Thinking
Chapter 20 Of Modes of Pleasure and Pain
Chapter 21 Of Power
Chapter 22 Of Mixed Modes
Chapter 23 Of our Complex Ideas of Substances
Chapter 24 Of Collective Ideas of Substances
Chapter 25 Of Relation
Chapter 26 Of Cause and Effect, and other Relations
Chapter 27 Of Identity and Diversity
Chapter 28 Of other Relations
Chapter 29 Of Clear and Obscure, Distinct and Confused Ideas
Chapter 30 Of Real and Fantastical Ideas
Chapter 31 Of Adequate and Inadequate Ideas
Chapter 32 Of True and False Ideas
Chapter 33 Of the Association of Ideas
Book III - Of Words
Chapter 01 Of Words or Language Generally
Chapter 02 Of the Signification of Words
Chapter 03 Of General Terms
Chapter 04 Of the Names of Simple Ideas
Chapter 05 Of the Names of Mixed Modes and Relations
Chapter 06 Of the Names of Substances
Chapter 07 Of Particles
Chapter 08 Of Abstract and Concrete Terms
Chapter 09 Of the Imperfection of Words
Chapter 10 Of the Abuse of Words
Chapter 11 Of the Remedies of the Foregoing Imperfections and Abuses of Words
Book IV - Of Knowledge and Probability
Chapter 01 Of Knowledge in General
Chapter 02 Of the Degrees of our Knowledge
Chapter 03 Of the Extent of Human Knowledge
Chapter 04 Of the Reality of Knowledge
Chapter 05 Of Truth in General
Chapter 06 Of Universal Propositions: their Truth and Certainty
Chapter 07 Of Maxims
Chapter 08 Of Trifling Propositions
Chapter 09 Of our Threefold Knowledge of Existence
Chapter 10 Of our Knowledge of the Existence of a God
Chapter 11 Of our Knowledge of the Existence of other Things
Chapter 12 Of the Improvement of our Knowledge
Chapter 13 Some Further Considerations Concerning our Knowledge
Chapter 14 Of Judgment
Chapter 15 Of Probability
Chapter 16 Of the Degrees of Assent
Chapter 17 Of Reason
Chapter 18 Of Faith and Reason, and their Distinct Provinces
Chapter 19 Of Enthusiasm
Chapter 20 Of Wrong Assent, or Error
Chapter 21 Of the Division of the Sciences
Letter to the Right Honorable Lord Thomas, et al.
To the right honourable lord Thomas, earl of pembroke and montgomery, barron herbert of cardiff, lord ross, of kendal, par, fitzhugh, marmion, st. quintin, and shurland ; lord president of his majesty's most honourable privy council ; and lord lieutenant of the county of wilts, and of south wales.
THIS Treatise, which is grown up under your lordship's eye, and has ventured into the world by your order, does now, by a natural kind of right, come to your lordship for that protection which you several years since promised it. It is not that I think any name, how great soever, set at the beginning of a book, will be able to cover the faults that are to be found in it. Things in print must stand and fall by their own worth, or the reader's fancy. But there being nothing more to be desired for truth than a fair unprejudiced hearing, nobody is more likely to procure me that than your lordship, who are allowed to have got so intimate an acquaintance with her, in her more retired recesses. Your lordship is known to have so far advanced your speculations in the most abstract and general knowledge of things, beyond the ordinary reach or common methods, that your allowance and approbation of the design of this Treatise will at least preserve it from being condemned without reading, and will prevail to have those parts a little weighted, which might otherwise perhaps be thought to deserve no consideration, for being somewhat out of the common road. The imputation of Novelty is a terrible charge amongst those who judge of men's heads, as they do of their perukes, by the fashion, and can allow none to be right but the received doctrines. Truth scarce ever yet carried it by vote anywhere at its first appearance : new opinions are always suspected, and usually opposed, without any other reason but because they are not already common. But truth, like gold, is not the less so for being newly brought out of the mine. It is trial and examination must give it price, and not any antique fashion ; and though it be not yet current by the public stamp, yet it may, for all that, be as old as nature, and is certainly not the less genuine. Your lordship can give great and convincing instances of this, whenever you please to oblige the public with some of those large and comprehensive discoveries you have made of truths hitherto unknown, unless to some few, from whom your lordship has been pleased not wholly to conceal them. This alone were a sufficient reason, were there no other, why I should dedicate this Essay to your lordship ; and its having some little correspondence with some parts of that nobler and vast system of the sciences your lordship has made so new, exact, and instructive a draught of, I think it glory enough, if your lordship permit me to boast, that here and there I have fallen into some thoughts not wholly different from yours. If your lordship think fit that, by your encouragement, this should appear in the world, I hope it may be a reason, some time or other, to lead your lordship further ; and you will allow me to say, that you here give the world an earnest of something that, if they can bear with this, will be truly worth their expectation. This, my lord, shows what a present I here make to your lordship ; just such as the poor man does to his rich and great neighbour, by whom the basket of flowers or fruit is not ill taken, though he has more plenty of his own growth, and in much greater perfection. Worthless things receive a value when they are made the offerings of respect, esteem, and gratitude : these you have given me so mighty and peculiar reasons to have, in the highest degree, for your lordship, that if they can add a price to what they go along with, proportionable to their own greatness, I can with confidence brag, I here make your lordship the richest present you ever received. This I am sure, I am under the greatest obligations to seek all occasions to acknowledge a long train of favours I have received from your lordship ; favours, though great and important in themselves, yet made much more so by the forwardness, concern, and kindness, and other obliging circumstances, that never failed to accompany them. To all this you are pleased to add that which gives yet more weight and relish to all the rest : you vouchsafe to continue me in some degrees of your esteem, and allow me a place in your good thoughts, I had almost said friendship. This, my lord, your words and actions so constantly show on all occasions, even to others when I am absent, that it is not vanity in me to mention what everybody knows : but it would be want of good manners not to acknowledge what so many are witnesses of, and every day tell me I am indebted to your lordship for. I wish they could as easily assist my gratitude, as they convince me of the great and growing engagements it has to your lordship. This I am sure, I should write of the Understanding without having any, if I were not extremely sensible of them, and did not lay hold on this opportunity to testify to the world how much I am obliged to be, and how much I am,
Your Lordship's most humble and most obedient servant,
24th of May, 1689
EPISTLE TO THE READER
I HAVE put into thy hands what has been the diversion of some of my idle and heavy hours. If it has the good luck to prove so of any of thine, and thou hast but half so much pleasure in reading as I had in writing it, thou wilt as little think thy money, as I do my pains, ill bestowed. Mistake not this for a commendation of my work ; nor conclude, because I was pleased with the doing of it, that therefore I am fondly taken with it now it is done. He that hawks at larks and sparrows has no less sport, though a much less considerable quarry, than he that flies at nobler game : and he is little acquainted with the subject of this treatise- the UNDERSTANDING- who does not know that, as it is the most elevated faculty of the soul, so it is employed with a greater and more constant delight than any of the other. Its searches after truth are a sort of hawking and hunting, wherein the very pursuit makes a great part of the pleasure. Every step the mind takes in its progress towards Knowledge makes some discovery, which is not only new, but the best too, for the time at least.
For the understanding, like the eye, judging of objects only by its own sight, cannot but be pleased with what it discovers, having less regret for what has escaped it, because it is unknown. Thus he who has raised himself above the alms-basket, and, not content to live lazily on scraps of begged opinions, sets his own thoughts on work, to find and follow truth, will (whatever he lights on) not miss the hunter's satisfaction ; every moment of his pursuit will reward his pains with some delight ; and he will have reason to think his time not ill spent, even when he cannot much boast of any great acquisition.
This, Reader, is the entertainment of those who let loose their own thoughts, and follow them in writing ; which thou oughtest not to envy them, since they afford thee an opportunity of the like diversion, if thou wilt make use of thy own thoughts in reading. It is to them, if they are thy own, that I refer myself : but if they are taken upon trust from others, it is no great matter what they are ; they are not following truth, but some meaner consideration ; and it is not worth while to be concerned what he says or thinks, who says or thinks only as he is directed by another. If thou judgest for thyself I know thou wilt judge candidly, and then I shall not be harmed or offended, whatever be thy censure. For though it be certain that there is nothing in this Treatise of the truth whereof I am not fully persuaded, yet I consider myself as liable to mistakes as I can think thee, and know that this book must stand or fall with thee, not by any opinion I have of it, but thy own. If thou findest little in it new or instructive to thee, thou art not to blame me for it. It was not meant for those that had already mastered this subject, and made a thorough acquaintance with their own understandings ; but for my own information, and the satisfaction of a few friends, who acknowledged themselves not to have sufficiently considered it.
Were it fit to trouble thee with the history of this Essay, I should tell thee, that five or six friends meeting at my chamber, and discoursing on a subject very remote from this, found themselves quickly at a stand, by the difficulties that rose on every side. After we had awhile puzzled ourselves, without coming any nearer a resolution of those doubts which perplexed us, it came into my thoughts that we took a wrong course ; and that before we set ourselves upon inquiries of that nature, it was necessary to examine our own abilities, and see what objects our understandings were, or were not, fitted to deal with. This I proposed to the company, who all readily assented ; and thereupon it was agreed that this should be our first inquiry. Some hasty and undigested thoughts, on a subject I had never before considered, which I set down against our next meeting, gave the first entrance into this Discourse ; which having been thus begun by chance, was continued by intreaty ; written by incoherent parcels ; and after long intervals of neglect, resumed again, as my humour or occasions permitted ; and at last, in a retirement where an attendance on my health gave me leisure, it was brought into that order thou now seest it.
This discontinued way of writing may have occasioned, besides others, two contrary faults, viz., that too little and too much may be said in it. If thou findest anything wanting, I shall be glad that what I have written gives thee any desire that I should have gone further. If it seems too much to thee, thou must blame the subject ; for when I put pen to paper, I thought all I should have to say on this matter would have been contained in one sheet of paper ; but the further I went the larger prospect I had ; new discoveries led me still on, and so it grew insensibly to the bulk it now appears in. I will not deny, but possibly it might be reduced to a narrower compass than it is, and that some parts of it might be contracted, the way it has been writ in, by catches, and many long intervals of interruption, being apt to cause some repetitions. But to confess the truth, I am now too lazy, or too busy, to make it shorter.
I am not ignorant how little I herein consult my own reputation, when I knowingly let it go with a fault, so apt to disgust the most judicious, who are always the nicest readers. But they who know sloth is apt to content itself with any excuse, will pardon me if mine has prevailed on me, where I think I have a very good one. I will not therefore allege in my defence, that the same notion, having different respects, may be convenient or necessary to prove or illustrate several parts of the same discourse, and that so it has happened in many parts of this : but waiving that, I shall frankly avow that I have sometimes dwelt long upon the same argument, and expressed it different ways, with a quite different design. I pretend not to publish this Essay for the information of men of large thoughts and quick apprehensions ; to such masters of knowledge I profess myself a scholar, and therefore warn them beforehand not to expect anything here, but what, being spun out of my own coarse thoughts, is fitted to men of my own size, to whom, perhaps, it will not be unacceptable that I have taken some pains to make plain and familiar to their thoughts some truths which established prejudice, or the abstractedness of the ideas themselves, might render difficult. Some objects had need be turned on every side ; and when the notion is new, as I confess some of these are to me ; or out of the ordinary road, as I suspect they will appear to others, it is not one simple view of it that will gain it admittance into every understanding, or fix it there with a clear and lasting impression. There are few, I believe, who have not observed in themselves or others, that what in one way of proposing was very obscure, another way of expressing it has made very clear and intelligible ; though afterwards the mind found little difference in the phrases, and wondered why one failed to be understood more than the other. But everything does not hit alike upon every man's imagination. We have our understandings no less different than our palates ; and he that thinks the same truth shall be equally relished by every one in the same dress, may as well hope to feast every one with the same sort of cookery : the meat may be the same, and the nourishment good, yet every one not be able to receive it with that seasoning ; and it must be dressed another way, if you will have it go down with some, even of strong constitutions. The truth is, those who advised me to publish it, advised me, for this reason, to publish it as it is : and since I have been brought to let it go abroad, I desire it should be understood by whoever gives himself the pains to read it. I have so little affection to be in print, that if I were not flattered this Essay might be of some use to others, as I think it has been to me, I should have confined it to the view of some friends, who gave the first occasion to it. My appearing therefore in print being on purpose to be as useful as I may, I think it necessary to make what I have to say as easy and intelligible to all sorts of readers as I can. And I had much rather the speculative and quick-sighted should complain of my being in some parts tedious, than that any one, not accustomed to abstract speculations, or prepossessed with different notions, should mistake or not comprehend my meaning.
It will possibly be censured as a great piece of vanity or insolence in me, to pretend to instruct this our knowing age ; it amounting to little less, when I own, that I publish this Essay with hopes it may be useful to others. But, if it may be permitted to speak freely of those who with a feigned modesty condemn as useless what they themselves write, methinks it savours much more of vanity or insolence to publish a book for any other end ; and he fails very much of that respect he owes the public, who prints, and consequently expects men should read, that wherein he intends not they should meet with anything of use to themselves or others : and should nothing else be found allowable in this Treatise, yet my design will not cease to be so ; and the goodness of my intention ought to be some excuse for the worthlessness of my present. It is that chiefly which secures me from the fear of censure, which I expect not to escape more than better writers. Men's principles, notions, and relishes are so different, that it is hard to find a book which pleases or displeases all men. I acknowledge the age we live in is not the least knowing, and therefore not the most easy to be satisfied. If I have not the good luck to please, yet nobody ought to be offended with me. I plainly tell all my readers, except half a dozen, this Treatise was not at first intended for them ; and therefore they need not be at the trouble to be of that number. But yet if any one thinks fit to be angry and rail at it, he may do it securely, for I shall find some better way of spending my time than in such kind of conversation. I shall always have the satisfaction to have aimed sincerely at truth and usefulness, though in one of the meanest ways. The commonwealth of learning is not at this time without master-builders, whose mighty designs, in advancing the sciences, will leave lasting monuments to the admiration of posterity : but every one must not hope to be a Boyle or a Sydenham ; and in an age that produces such masters as the great Huygenius and the incomparable Mr. Newton, with some others of that strain, it is ambition enough to be employed as an under-labourer in clearing the ground a little, and removing some of the rubbish that lies in the way to knowledge ;- which certainly had been very much more advanced in the world, if the endeavours of ingenious and industrious men had not been much cumbered with the learned but frivolous use of uncouth, affected, or unintelligible terms, introduced into the sciences, and there made an art of, to that degree that Philosophy, which is nothing but the true knowledge of things, was thought unfit or incapable to be brought into well-bred company and polite conversation. Vague and insignificant forms of speech, and abuse of language, have so long passed for mysteries of science ; and hard and misapplied words, with little or no meaning, have, by prescription, such a right to be mistaken for deep learning and height of speculation, that it will not be easy to persuade either those who speak or those who hear them, that they are but the covers of ignorance, and hindrance of true knowledge. To break in upon the sanctuary of vanity and ignorance will be, I suppose, some service to human understanding ; though so few are apt to think they deceive or are deceived in the use of words ; or that the language of the sect they are of has any faults in it which ought to be examined or corrected, that I hope I shall be pardoned if I have in the Third Book dwelt long on this subject, and endeavoured to make it so plain, that neither the inveterateness of the mischief, nor the prevalency of the fashion, shall be any excuse for those who will not take care about the meaning of their own words, and will not suffer the significancy of their expressions to be inquired into.
I have been told that a short Epitome of this Treatise, which was printed in 1688, was by some condemned without reading, because innate ideas were denied in it ; they too hastily concluding, that if innate ideas were not supposed, there would be little left either of the notion or proof of spirits. If any one take the like offence at the entrance of this Treatise, I shall desire him to read it through ; and then I hope he will be convinced, that the taking away false foundations is not to the prejudice but advantage of truth, which is never injured or endangered so much as when mixed with, or built on, falsehood.
In the Second Edition I added as followeth :-
The bookseller will not forgive me if I say nothing of this New Edition, which he has promised, by the correctness of it, shall make amends for the many faults committed in the former. He desires too, that it should be known that it has one whole new chapter concerning Identity, and many additions and amendments in other places. These I must inform my reader are not all new matter, but most of them either further confirmation of what I had said, or explications, to prevent others being mistaken in the sense of what was formerly printed, and not any variation in me from it.
I must only except the alterations I have made in Book II. chap. xxi.
What I had there written concerning Liberty and the Will, I thought deserved as accurate a view as I am capable of ; those subjects having in all ages exercised the learned part of the world with questions and difficulties, that have not a little perplexed morality and divinity, those parts of knowledge that men are most concerned to be clear in. Upon a closer inspection into the working of men's minds, and a stricter examination of those motives and views they are turned by, I have found reason somewhat to alter the thoughts I formerly had concerning that which gives the last determination to the Will in all voluntary actions. This I cannot forbear to acknowledge to the world with as much freedom and readiness as I at first published what then seemed to me to be right ; thinking myself more concerned to quit and renounce any opinion of my own, than oppose that of another, when truth appears against it. For it is truth alone I seek, and that will always be welcome to me, when or from whencesoever it comes.
But what forwardness soever I have to resign any opinion I have, or to recede from anything I have writ, upon the first evidence of any error in it ; yet this I must own, that I have not had the good luck to receive any light from those exceptions I have met with in print against any part of my book, nor have, from anything that has been urged against it, found reason to alter my sense in any of the points that have been questioned. Whether the subject I have in hand requires often more thought and attention than cursory readers, at least such as are prepossessed, are willing to allow ; or whether any obscurity in my expressions casts a cloud over it, and these notions are made difficult to others' apprehensions in my way of treating them ; so it is, that my meaning, I find, is often mistaken, and I have not the good luck to be everywhere rightly understood.
Of this the ingenious author of the Discourse Concerning the Nature of Man has given me a late instance, to mention no other. For the civility of his expressions, and the candour that belongs to his order, forbid me to think that he would have closed his Preface with an insinuation, as if in what I had said, Book II. ch. xxvii, concerning the third rule which men refer their actions to, I went about to make virtue vice and vice virtue unless he had mistaken my meaning ; which he could not have done if he had given himself the trouble to consider what the argument was I was then upon, and what was the chief design of that chapter, plainly enough set down in the fourth section and those following. For I was there not laying down moral rules, but showing the original and nature of moral ideas, and enumerating the rules men make use of in moral relations, whether these rules were true or false : and pursuant thereto I tell what is everywhere called virtue and vice ; which "alters not the nature of things," though men generally do judge of and denominate their actions according to the esteem and fashion of the place and sect they are of.
If he had been at the pains to reflect on what I had said, Bk. I. ch. ii. sect. 18, and Bk. II. ch. xxviii. sects. 13, 14, 15 and 20, he would have known what I think of the eternal and unalterable nature of right and wrong, and what I call virtue and vice. And if he had observed that in the place he quotes I only report as a matter of fact what others call virtue and vice, he would not have found it liable to any great exception. For I think I am not much out in saying that one of the rules made use of in the world for a ground or measure of a moral relation is- that esteem and reputation which several sorts of actions find variously in the several societies of men, according to which they are there called virtues or vices. And whatever authority the learned Mr. Lowde places in his Old English Dictionary, I daresay it nowhere tells him (if I should appeal to it) that the same action is not in credit, called and counted a virtue, in one place, which, being in disrepute, passes for and under the name of vice in another. The taking notice that men bestow the names of "virtue" and "vice" according to this rule of Reputation is all I have done, or can be laid to my charge to have done, towards the making vice virtue or virtue vice. But the good man does well, and as becomes his calling, to be watchful in such points, and to take the alarm even at expressions, which, standing alone by themselves, might sound ill and be suspected.
'Tis to this zeal, allowable in his function, that I forgive his citing as he does these words of mine (ch. xxviii. sect. II) : "Even the exhortations of inspired teachers have not feared to appeal to common repute, Philip. iv. 8" ; without taking notice of those immediately preceding, which introduce them, and run thus : "Whereby even in the corruption of manners, the true boundaries of the law of nature, which ought to be the rule of virtue and vice, were pretty well preserved. So that even the exhortations of inspired teachers," &c. By which words, and the rest of that section, it is plain that I brought that passage of St. Paul, not to prove that the general measure of what men called virtue and vice throughout the world was, the reputation and fashion of each particular society within itself ; but to show that, though it were so, yet, for reasons I there give, men, in that way of denominating their actions, did not for the most part much stray from the Law of Nature ; which is that standing and unalterable rule by which they ought to judge of the moral rectitude and gravity of their actions, and accordingly denominate them virtues or vices. Had Mr. Lowde considered this, he would have found it little to his purpose to have quoted this passage in a sense I used it not ; and would I imagine have spared the application he subjoins to it, as not very necessary. But I hope this Second Edition will give him satisfaction on the point, and that this matter is now so expressed as to show him there was no cause for scruple.
Though I am forced to differ from him in these apprehensions he has expressed, in the latter end of his preface, concerning what I had said about virtue and vice, yet we are better agreed than he thinks in what he says in his third chapter (p. 78) concerning "natural inscription and innate notions." I shall not deny him the privilege he claims (p. 52), to state the question as he pleases, especially when he states it so as to leave nothing in it contrary to what I have said. For, according to him, "innate notions, being conditional things, depending upon the concurrence of several other circumstances in order to the soul's exerting them," all that he says for "innate, imprinted, impressed notions" (for of innate ideas he says nothing at all), amounts at last only to this- that there are certain propositions which, though the soul from the beginning, or when a man is born, does not know, yet "by assistance from the outward senses, and the help of some previous cultivation," it may afterwards come certainly to know the truth of ; which is no more than what I have affirmed in my First Book. For I suppose by the "soul's exerting them," he means its beginning to know them ; or else the soul's "exerting of notions" will be to me a very unintelligible expression ; and I think at best is a very unfit one in this, it misleading men's thoughts by an insinuation, as if these notions were in the mind before the "soul exerts them," i.e. before they are known ;- whereas truly before they are known, there is nothing of them in the mind but a capacity to know them, when the "concurrence of those circumstances," which this ingenious author thinks necessary "in order to the soul's exerting them," brings them into our knowledge.
P. 52 I find him express it thus : "These natural notions are not so imprinted upon the soul as that they naturally and necessarily exert themselves (even in children and idiots) without any assistance from the outward senses, or without the help of some previous cultivation." Here, he says, they exert themselves, as p. 78, that the "soul exerts them." When he has explained to himself or others what he means by "the soul's exerting innate notions," or their "exerting themselves" ; and what that "previous cultivation and circumstances" in order to their being exerted are- he will I suppose find there is so little of controversy between him and me on the point, bating that he calls that "exerting of notions" which I in a more vulgar style call "knowing," that I have reason to think he brought in my name on this occasion only out of the pleasure he has to speak civilly of me ; which I must gratefully acknowledge he has done everywhere he mentions me, not without conferring on me, as some others have done, a title I have no right to.
There are so many instances of this, that I think it justice to my reader and myself to conclude, that either my book is plainly enough written to be rightly understood by those who peruse it with that attention and indifferency, which every one who will give himself the pains to read ought to employ in reading ; or else that I have written mine so obscurely that it is in vain to go about to mend it. Whichever of these be the truth, it is myself only am affected thereby ; and therefore I shall be far from troubling my reader with what I think might be said in answer to those several objections I have met with, to passages here and there of my book ; since I persuade myself that he who thinks them of moment enough to be concerned whether they are true or false, will be able to see that what is said is either not well founded, or else not contrary to my doctrine, when I and my opposer come both to be well understood.
If any other authors, careful that none of their good thoughts should be lost, have published their censures of my Essay, with this honour done to it, that they will not suffer it to be an essay, I leave it to the public to value the obligation they have to their critical pens, and shall not waste my reader's time in so idle or ill-natured an employment of mine, as to lessen the satisfaction any one has in himself, or gives to others, in so hasty a confutation of what I have written.
The booksellers preparing for the Fourth Edition of my Essay, gave me notice of it, that I might, if I had leisure, make any additions or alterations I should think fit. Whereupon I thought it convenient to advertise the reader, that besides several corrections I had made here and there, there was one alteration which it was necessary to mention, because it ran through the whole book, and is of consequence to be rightly understood. What I thereupon said was this :-
Clear and distinct ideas are terms which, though familiar and frequent in men's mouths, I have reason to think every one who uses does not perfectly understand. And possibly 'tis but here and there one who gives himself the trouble to consider them so far as to know what he himself or others precisely mean by them. I have therefore in most places chose to put determinate or determined, instead of clear and distinct, as more likely to direct men's thoughts to my meaning in this matter. By those denominations, I mean some object in the mind, and consequently determined, i.e. such as it is there seen and perceived to be. This, I think, may fitly be called a determinate or determined idea, when such as it is at any time objectively in the mind, and so determined there, it is annexed, and without variation determined, to a name or articulate sound, which is to be steadily the sign of that very same object of the mind, or determinate idea.
To explain this a little more particularly. By determinate, when applied to a simple idea, I mean that simple appearance which the mind has in its view, or perceives in itself, when that idea is said to be in it : by determined, when applied to a complex idea, I mean such an one as consists of a determinate number of certain simple or less complex ideas, joined in such a proportion and situation as the mind has before its view, and sees in itself, when that idea is present in it, or should be present in it, when a man gives a name to it. I say should be, because it is not every one, nor perhaps any one, who is so careful of his language as to use no word till he views in his mind the precise determined idea which he resolves to make it the sign of The want of this is the cause of no small obscurity and confusion in men's thoughts and discourses.
I know there are not words enough in any language to answer all the variety of ideas that enter into men's discourses and reasonings. But this hinders not but that when any one uses any term, he may have in his mind a determined idea, which he makes it the sign of, and to which he should keep it steadily annexed during that present discourse. Where he does not, or cannot do this, he in vain pretends to clear or distinct ideas : it is plain his are not so ; and therefore there can be expected nothing but obscurity and confusion, where such terms are made use of which have not such a precise determination.
Upon this ground I have thought determined ideas a way of speaking less liable to mistakes, than clear and distinct : and where men have got such determined ideas of all that they reason, inquire, or argue about, they will find a great part of their doubts and disputes at an end ; the greatest part of the questions and controversies that perplex mankind depending on the doubtful and uncertain use of words, or (which is the same) indetermined ideas, which they are made to stand for. I have made choice of these terms to signify, (1) Some immediate object of the mind, which it perceives and has before it, distinct from the sound it uses as a sign of it. (2) That this idea, thus determined, i.e. which the mind has in itself, and knows, and sees there, be determined without any change to that name, and that name determined to that precise idea. If men had such determined ideas in their inquiries and discourses, they would both discern how far their own inquiries and discourses went, and avoid the greatest part of the disputes and wranglings they have with others.
Besides this, the bookseller will think it necessary I should advertise the reader that there is an addition of two chapters wholly new ; the one of the Association of Ideas, the other of Enthusiasm. These, with some other larger additions never before printed, he has engaged to print by themselves, after the same manner, and for the same purpose, as was done when this Essay had the second impression.
In the Sixth Edition there is very little added or altered. The greatest part of what is new is contained in the twenty-first chapter of the second book, which any one, if he thinks it worth while, may, with a very little labour, transcribe into the margin of the former edition. INTRODUCTION