§. 2. Knowledge then seems to me to be Knowledge nothing but the perception of the connexion is the perand agreement, or disagreement and repug- the agree ception of nancy, of any of our ideas. In this alone ment or disit consists. Where this perception is, there agreement of two ideas, is knowledge; and where it is not, there, though we may fancy, guess, or believe, yet we always come short of knowledge. For when we know that white is not black, what do we else but perceive that these two ideas do not agree? When we possess ourselves with the utmost security of the demonstration, that the three angles of a triangle are equal to two right ones, what do we more but perceive, that equality to two right ones does necessarily agree to, and is inseparable from the three angles of a triangle?*

The placing of certainty, as Mr. Locke does, in the perception of the agreement or disagreement of our ideas, the bishop of Worcester suspects may be of dangerous consequence to that article of faith which he has endeavoured to defend; to which Mr. Locke answers, Since your lordship hath not, as I remember, shown, or gone about to show, how this proposition, viz. that certainty consists in the perception of agreement or disagreement of two ideas, is opposite or inconsistent with that article of faith which your lordship has endeavoured to defend; it is plain, it is but your lordship's fear, that it may be of dangerous consequence to it, which, as I humbly conceive, is no proof that it is any way inconsistent with that article.

Nobody, I think, can blame your lordship, or any one else, for being concerned for any article of the christian faith; but if that concern (as it may, and as we know it has done) makes any one apprehend danger, where no danger is, are we, therefore, to give up and condemn any proposition, because any one, though of the first rank and magnitude, fears it may be of dangerous consequence to any truth of religion, without showing that it is so? If such fears be the measures whereby to judge of truth and falsehood, the affirming that there are antipodes would be still a heresy; and the doctrine of the motion of the earth must be rejected, as overthrowing the truth of the scripture; for of that dangerous consequence it has been apprehended to be, by many learned and pious divines, ont of their great concern for religion. And yet, notwithstanding those great apprehensions of what dangerous consequence it might be, it is now universally received by learned men, as an undoubted truth; and writ for by some, whose belief of the scripture is not at all questioned; and particu larly, very lately, by a divine of the church of England, with great strength of reason, in his wonderfully ingenious New Theory of the Earth,

+ In his 2d letter to the bishop of Worcester.

This agreement fourfold.

§. 3. But to understand a little more distinctly wherein this agreement or disagreement consists, I think we may reduce it all to these four sorts:

1. Identity, or diversity.

2. Relation.

3. Co-existence, or necessary connexion. 4. Real existence.

1. Of iden

sity.

§. 4. First, as to the first sort of agreetity or diver- ment or disagreement, viz. identity or diversity. It is the first act of the mind, when it has any sentiments or ideas at all, to perceive its ideas; and so far as it perceives them, to know each what it is, and thereby also to perceive their difference, and that one is not another. This is so abso

The reason your lordship gives of your fears, that it may be of such dangerous consequence to that article of faith which your lordship endeavours to defend, though it occur in more places than one, is only this, yiz. That it is made use of by ill men to do mischief, i. e. to oppose that article of faith which your lordship hath endeavoured to defend. But, my lord, if it be a reason to lay by any thing as bad, because it is, or may be used to an ill purpose, I know not what will be innocent enough to be kept. Arms, which were made for our defence, are sometimes made use of to do mischief; and yet they are not thought of dangerous Consequence for all that. Nobody lays by his sword and pistols, or thinks them of such dangerous consequence as to be neglected, or thrown away, because robbers, and the worst of men, sometimes make use of them, to take away honest men's lives or goods. And the reason is, because they were designed, and will serve to preserve them. And who knows but this may be the present case? If your lordship thinks, that placing of certainty in the perception of the agreement or disagreement of ideas be to be rejected as false, because you apprehend it may be of dangerous consequence to that article of faith: on the other side, perhaps others, with me, may think it a defence against error, and so (as being of good use) to be received and adhered to.

I would not, my lord, be hereby thought to set up my own, or any one's judgment against your lordship's. But I have said this only to show, whilst the argument lies for or against the truth of any proposition, barely in an imagination that it may be of consequence to the supporting or overthrowing of any remote truth; it will be impossible, that way, to determine of the truth or falsehood of that proposition. For imagination will be set up against imagination, and the stronger probably will be against your lordship; the strongest imaginations being usually in the weakest heads. The only way, in this case, to put it past doubt, is to show the inconsistency of the two propositions; and then it will be seen, that one overthrows the other; the true, the false one.

lutely necessary, that without it there could be no knowledge, no reasoning, no imagination, no distinct thoughts, at all. By this the mind clearly and infallibly perceives each idea to agree with itself, and to be what it is; and all distinct ideas to disagree, i. e. the one not to be the other and this it does without pains, labour, or deduction; but at first view, by its natural power of perception and distinction. And though men of art have reduced this into those general rules, "what is, is ;" and "it is impossible for the same thing to be and not to be;" for ready application in all cases, wherein there may be occasion to reflect on it: yet it is certain, that the first exercise of this faculty is about particular ideas. A man infallibly knows, as soon as ever he has them in his mind, that the ideas he calls white and round, are

Your lordship says, indeed, this is a new method of certainty. I will not say so myself, for fear of deserving a second reproof from your lordship, for being too forward to assume to myself the honour of being an original. But this, I think, gives me occasion, and will excuse me from being thought impertinent, if I ask your lordship whether there be any other, or older method of certainty? and what it is? For if there be no other, nor older than this, either this was always the method of certainty, and so mine is no new one; or else the world is obliged to me for this new one, after having been so long in the want of so necessary a thing as a method of certainty. If there be an older, I am sure your lordship cannot but know it; your condemning mine as new, as well as your thorough insight into antiquity, cannot but satisfy every body that you do. And therefore to set the world right in a thing of that great concernment, and to overthrow mine, and thereby prevent the dangerous consequence there is in my having unreasonably started it, will not, I humbly conceive, misbecome your lordship's care of that article you have endeavoured to defend, nor the good-will you bear to truth in general. For I will be answerable for myself, that I shall; and I think I may be for all others, that they all will give off the placing of certainty in the perception of the agreement or disagreement of ideas, if your lordship will be pleased to show, that it lies in any thing else.

But truly, not to ascribe to myself an invention of what has been as old as knowledge is in the world, I must own I am not guilty of what your lordship is pleased to call starting new methods of certainty. Knowledge, ever since there has been any in the world, has consisted in one particular action in the mind; and so, I conceive, will continue to do to the end of it. And to start new methods of knowledge, or certainty, (for they are to me the same thing) i. e. to find out and propose new methods of attaining knowledge, either with more ease and quickness, or in things yet unknown, is what I think nobody could blame: but this is not that which your lordship here means, by new methods of certainty. Your

the very ideas they are, and that they are not other ideas which he calls red or square. Nor can any maxim or proposition in the world make him know it clearer or surer than he did before, and without any such general rule. This then is the first agreement or disagreement, which the mind perceives in its ideas; which it always perceives at first sight: and if there ever happen anydoubt about it, it will always be found to be about the names, and not the ideas themselves, whose identity and diversity will always be perceived, as soon and clearly as the ideas themselves are; uor can it possibly be otherwise. §. 5. Secondly, the next sort of agreement or disagreement, the mind perceives in any of its ideas, may, I think, be called relative, and is nothing but the perception of the relation between

2. Relative.

lordship, I think, means by it, the placing of certainty in something, wherein either it does not consist, or else wherein it was not placed before now; if this be to be called a new method of certainty. As to the latter of these, I shall know whether I am guilty or no, when your lordship will do me the favour to tell me, wherein it was placed before: which your lordship knows I professed myself ignorant of, when I writ my book, and so I am still. But if starting new methods of certainty, be the placing of certainty in something wherein it does not consist: whether I have done that or no, I must appeal to the experience of mankind.

There are several actions of men's minds, that they are conscious to themselves of performing, as willing, believing, knowing, &c. which they have so particular sense of, that they can distinguish them one from another; or else they could not say, when they willed, when they believed, and when they knew any thing. But though these actions were different enough from one another, not to be confounded by those who spoke of them, yet nobody, that I had met with, had, in their writings, particu larly set down wherein the act of knowing precisely consisted.

To this reflection upon the actions of my own mind the subject of my Essay concerning Human Understanding naturally led me; wherein if I have done any thing new, it has been to describe to others, more particu larly than had been done before, what it is their minds do when they perform that action which they call knowing; and if, upon examination, they observe I have given a true account of that action of their minds in all the parts of it, I suppose it will be in vain to dispute against what they find and feel in themselves. And if I have not told them right and exactly what they find and feel in themselves, when their minds perform the act of knowing, what I have said will be all in vain; men will not be pernaded against their senses. Knowledge is an internal perception of their minds; and if, when they reflect on it, they find it is not what I have said it is, my groundless conceit will not be hearkened to, but be exploded by every body, and die of itself: and nobody need to be at any pains to

any two ideas, of what kind soever, whether substances, modes, or any other. For since all distinct ideas must eternally be known not to be the same, and so be universally and constantly denied one of another, there could be no room for any positive knowledge at all, if we could not perceive any relation between our ideas, and find out the agreement or disagreement they have one with another, in several ways the mind takes of com paring them.

§. 6. Thirdly, the third sort of agree- 3. Of co-exment, or disagreement, to be found in our istence. ideas, which the perception of the mind is

employed about, is co-existence, or non co-existence in the same subject; and this belongs particularly to substances. Thus when we pronounce concerning gold

drive it out of the world. So impossible is it to find out, or start new methods of certainty, or to have them received, if any oue places it in any thing, but in that wherein it really consists: much less can any one be in danger to be misled into error, by any such new, and to every one visibly senseless project. Can it be supposed, that any one could start a new method of seeing, and persuade men thereby, that they do not see what they do see? Is it to be feared that any one can cast such a mist over their eyes, that they should not know when they see, and so be led out of their way by it?

Knowledge, I find in myself, and I conceive in others, consists in the perception of the agreement or disagreement of the immediate objects of the mind in thinking, which I call ideas; but whether it does so in others or no, must be determined by their own experience, reflecting upon the action of their mind in knowing; for that I cannot alter, nor, Ì think, they themselves. But whether they will call those immediate objects of their minds in thinking ideas or no, is perfectly in their own choice. If they dislike that name, they may call them notions or conceptions, or how they please; it matters not, if they use them so as to avoid obscurity and confusion. If they are constantly used in the same and a known sense, every one has the liberty to please himself in his terms; there lies neither truth, nor error, nor science, in that; though those that take them for things, and not for what they are, bare abitrary signs of our ideas, make a great deal ado often about them; as if some great matter lay in the use of this or that sound. All that I know, or can imagine of differ ence about them, is that those words are always best, whose significations are best known in the sense they are used; and so are least apt to breed confusion.

My lord, your lordship hath been pleased to find fault with my use of the new term, ideas, without telling me a better name for the immediate objects of the mind in thinking. Your lordship also has been pleased to had fault with my definition of knowledge, without doing me the favour