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of wranglers; but not of much use to the discovery of unknown truths, or to help the mind forwards in its search after knowledge. For who ever began to build his knowledge on this general proposition, what is, is; or, it is impossible for the same thing to be, and not to be: and from either of these, as from a principle of science, deduced a system of useful knowledge ? Wrong opinions often involving contradictions, one of these maxims, as a touch-stone, may serve well to show whither they lead. But yet, however fit to lay open the absurdity or mistake of a man's reasoning or opinion, they are of very little use for enlightening the understanding: and it will not be found, that the mind receives much help from them in its progress in knowledge; which would be neither less, nor less certain, were these two general propositions never thought on. It is true, as I have said, they sometimes serve in argumentation to stop a wrangler's mouth, by showing the absurdity of what he saith, and by exposing him to the shame of contradicting what all the world knows, and he himself cannot but own to be true. But it is one thing to show a man that he is in an error, and another to put him in possession of truth; and I would fain know what truths these two propositions are able to teach, and by their influence make us know, which we did not know before, or could not know without them. Let us reason from them as well as we can, they are only about identical predications, and influence, if any at all, none but such. Each particular proposition concerning identity or diversity is as clearly and certainly known in itself, if attended to, as either of these general ones: only these general ones, as serving in all cases, are therefore more inculcated and insisted on. As to other less general maxims, many of them are no more than bare verbal propositions, and teach us nothing but the respect and import of names one to another.
« The whole is equal to all its parts ;" what real truth, I beseech you, does it teach us? What more is contained in that maxim than what the signification of the word totum, or the whole, does of itself import? And he that kriows that the word whole stands for what is made up of all its parts, knows very little less than that the whole is equal to all its parts. And upon the same ground, I think that this proposition, a hill is higher than a valley, and several the like, may also pass for maxims. But yet masters of mathematics, when they would, as teachers of what they know, initiate others in that science, do not without reason place this, and some other such maxims, at the entrance of their systems; that their scholars, having in the beginning perfectly acquainted their thoughts with these propositions made in such general terms, may be used to make such reflections, and have these more general propositions, as formed rules and sayings, ready to apply to all particular cases. Not that, if they be equally weighed, they are more clear and evident than the particular instances they are brought to confirm; but that, being more familiar to the mind, the very naming them is enough to satisfy the understanding. But this, I say, is more from our custom of using them, and the establishment they have got in our minds, by our often thinking of them, than from the different evidence of the things. But before custom has settled methods of thinking and reasoning in our minds, I am apt to imagine it is quite otherwise; and that the child, when a part of his apple is taken away, knows it better in that particular instance than by this general proposition, the whole is equal to all its parts; and that if one of these have need to be confirmed to him by the other, the general has more need to be let into his mind by the particular, than the particular by the general. For in particulars our knowledge begins, and so spreads itself by degrees to generals. Though afterwards the mind takes the quite contrary course, and having drawn its knowledge into as general propositions as it can, makes those familiar to its thoughts, and accustoms itself to have recourse
to them, as to the standards of truth and falsehood. By which familiar use of them, as rules to measure the truth of other propositions, it comes in time to be thought, that more particular propositions have their truth and evidence from their conformity to these more general ones, which in discourse and argumentation are so frequently urged, and constantly admitted. And this I think to be the reason why, amongst so many self-evident propositions, the most general only have had the title of maxims.
§ 12. One thing farther, I think, it may Maxims, if not be amiss to observe concerning these care be not
taken in the general maxims, that they are so far from
use of words, improving or establishing our minds in
may prove true knowledge, that if our notions be contradicwrong, loose, or unsteady, and we resign tions. up our thoughts to the sound of words, rather than fix them on settled determined ideas of things; I say, these general maxims will serve to confirm us in mistakes; and in such a way of use of words, which is most common, will serve to prove contradictions: v. g. he that, with Des Cartes, sħall frame in his mind an idea of what he calls body to be nothing but extension, may easily demonstrate that there is no vacuum, i. e. no space void of body, by this maxim, what is, is. For the idea to which he annexes the name body being bare extension, his knowledge, that space cannot be without body, is certain. For he knows his own idea of extension clearly and distinctly, and knows that it is what it is, and not another idea, though it be called by these three names, extension, body, space. Which three words, standing for one and the same idea, may no doubt, with the same evidence and certainty, be affirmed one of another, as each of itself: and it is as certain, that whilst I use them all to stand for one and the same idea, this predication is as true and identical in its signification, that space is body, as this predication is true and identical, that body is body, both in signification and sound.
§ 13. But if another should come, and Instance in
make to himself another idea, different
from Des Cartes's, of the thing, which yet, with Des Cartes, he calls by the same name body; and make his idea, which he expresses by the word body, to be of a thing that hath both extension and solidity together; he will as easily demonstrate that there may be a vacuum or space without a body, as Des Cartes demonstrated the contrary. Because the idea to which he gives the name space being barely the simple one of extension; and the idea to which he gives the name body being the complex idea of extension and resistibility, or solidity, together in the same subject; these two ideas are not exactly one and the same, but in the understanding as distinct as the ideas of one and two, white and black, or as of corporeity and humanity, if I may use those barbarous terms: and therefore the predication of them in our minds, or in words standing for them, is not identical, but the negation of them one of another, viz. this proposition, extension or space is not body, is as true and evidently certain, as this maxim, it is impossible for the same thing to be, and not to be, can make any proposition. They prove
$ 14. But yet though both these pronot the ex- positions (as you see) may be equally demon
strated, viz. that there may be a vacuum, things with
and that there cannot be a vacuum, by
these two certain principles, viz. what is, is; and the same thing cannot be, and not be: yet neither of these principles will serve to prove to us, that any, or what bodies do exist: for that we are left to our senses, to discover to us as far as they can. Those universal and self-evident principles, being only our constant, clear, and distinct knowledge of our own ideas, more general or comprehensive, can assure us of nothing that passes without the mind; their certainty is founded only upon the knowledge we have of each idea by itself, and of its distinction from others;
about which we cannot be mistaken whilst they are in our minds, though we may, and often are mistaken when we retain the names without the ideas; or use them confusedly sometimes for one, and sometimes for another idea. In which cases the force of these axioms reaching only to the sound, and not the signification of the words, serves only to lead us into confusion, mistake, and error. It is to show men that these maxims, however cried up for the great guards of truth, will not secure them from error in a careless loose use of their words, that I have made this remark. In all that is here suggested concerning their little use for the improvement of knowledge, or dangerous use in undetermined ideas, I have been far enough from saying or intending they should be laid aside, as some have been too forward to charge me. I affirm them to be truths, self-evident truths; and so cannot be laid aside. As far as their influence will reach, it is in vain to endeavour, nor will I attempt to abridge it. But yet, without any injury to truth or knowledge, I may have reason to think their use is not answerable to the great stress which seems to be laid on them; and I may warn men not to make an ill use of them, for the confirming themselves in
$ 15. But let them be of what use they Their appliwill in verbal propositions, they cannot cation dandiscover or prove to us the least know- gerous about ledge of the nature of substances, as they complex
ideas. are found and exist without us, any farther than grounded on experience. And though the consequence of these two propositions, called principles, be very clear, and their use not dangerous or hurtful, in the probation of such things wherein there is no need at all of them for proof, but such as are clear by themselves without them, viz. where our ideas are determined, and known by the names that stand for them : yet when these principles, viz, what is, is ; and it is impossible for the same thing to be, and not