other idea returning conftantly at equidiftant periods, and making itself univerfally be taken notice of, would not fail to measure out the courfe of fucceffion, and diftinguifh the diftances of time. Thus we fee that men born blind count time well enough by years, whofe revolutions yet they cannot diftinguifh by mo tions that they perceive not: And I afk, Whether a blind man, who diftinguished his years either by the heat of fummer, or cold of winter, by the fmell of any flower of the fpring, or taste of any fruit of the autumn, would not have a better measure of time than the Romans had before the reformation of their calen dar by Julius Cæfar, or many other people, whofe years, notwithstanding the motion of the fun, which they pretend to make ufe of, are very irregular? And it adds no small difficulty to chronology, that the exact lengths of the years that feveral nations counted by, are hard to be known, they differing very much one from another, and I think I may say all of them from the precife motions of the fun. And if the fun moved from the creation to the flood conftantly in the equa tor, and fo equally difperfed its light and heat to all the habitable parts of the earth, in days all of the fame length, without its annual variations to the tropics, as a late ingenious author fuppofes; I do not think it very eafy to imagine, that (notwithstanding the motion of the fun) men fhould in the antediluvian world from the beginning count by years, or measure their time by periods, that had no fenfible marks very obvious to distinguish them by. § 21. No two Parts of Duration can be certainly known to be equal. 'BUT perhaps it will be faid, without a regular motion, fuch as of the fun, or fome other, how could it ever be known that fuch periods were equal? To which I anfwer, The equality of any other returning appearan❤ ces might be known by the fame way that that of days was known, or prefumed to be fo at firft; which was only by judging of them by the train of ideas which had paffed in mens minds in the intervals; by which train of ideas discovering inequality in the natural days, but none in the artificial days or Noxμge, were gueffed to be equal, which was fufficient to make them serve for a measure. Though exacter fearch has fince difcovered inequality in the diurnal revolutions of the fun, and we know not whether the annual alfo be not unequal, thefe yet, by their prefumed and apparent equality, ferve as well to reckon time by (though not to measure the parts of duration exactly), as if they could be proved to be exactly equal. We muft therefore carefully diftinguish betwixt duration itself, and the measures we make use of to judge of its length. Duration in itself is to be confidered as going on in one conftant, equal, uniform courfe; but none of the meafures of it, which we make use of, can be known to do fo; nor can we be affured, that their affigned parts or periods are equal in duration one to another; for two fucceffive lengths of duration, however measured, can never be demonftrated to be equal. The motion of the fun, which the world ufed fo long and fo confidently for an exact measure of duration, has, as I faid, been found in its feveral parts unequal; and though men have of late made ufe of a pendulum, as a more fleady and regular motion than that of the fun, or (to fpeak more truly) of the earth, yet if any one fhould be asked how he certainly knows that the two fucceffive fwings of a pendulum are equal, it would be very hard to fatisfy him that they are infallibly fo, fince we cannot be fure, that the cause of that motion, which is unknown to us, fhall always operate equally, and we are fure that the medium in which the pendulum moves, is not conftantly the fame; either of which varying, may alter the equality of fuch periods, and thereby deftroy the certainty and exactnefs of the meafure by motion, as well as any other periods of other appearances; the notion of duration ftill remaining clear, though our measures of it cannot any of them be demonftrated to be exact. Since then no two portions of fucceffion can be brought together, it is impoffible ever certainly to know their equality. All that we can do for a measure of time, is to take fuch as have continual fucceffive appearances at feemingly equidiftant periods; of which feeming equality we have no other measure, but fuch as the train of our own ideas have lodged in our memories, with the concurrence of other probable reasons, to perfuade us of their equality. $22. Time not the Measure of Motion. ONE thing feems ftrange to me, that whilst all men manifeftly measured time by the motion of the great and vifible bodies of the world, time yet fhould be defigned to be the measure of motion; whereas it is obvious to every one who reflects ever fo little on it, that to measure motion, space is as neceffary to be confidered as time; and those who look a little farther, will find alfo the bulk of the thing moved neceffary to be taken into the computation, by any one who will eftimate or measure motion, fo as to judge right of it. Nor indeed does motion any otherwise conduce to the measuring of duration, than as it conftantly brings about the return of certain fenfible ideas in feeming equidiftant periods: For, if the motion of the fun were as unequal as of a fhip driven by unfteady winds, fometimes very flow, and at others irregularly very swift; or if being constantly equally swift, it yet was not circular, and produced not the fame appearances, it would not at all help us to measure time, any more than the feeming unequal motion of a comet does. § 23. Minutes, Hours and Years, not necessary Measures of Duration. MINUTES, hours, days, and years, are then no more neceffary to time or duration, than inches, feet, yards, and miles, marked out in any matter, are to extenfion; for though we in this part of the universe, by the conftant use of them, as of periods fet out by the revolutions of the fun, or as known parts of fuch periods, have fixed the ideas of fuch lengths of duration in our minds, which we apply to all parts of time, whose lengths we would confider, yet there may be other parts of the univerfe, where they no more ufe thefe measures of ours, than in Japan they do our inches, feet,, or miles. But yet fomething analogous to them there must be; for without fome regular periodical returns, we could not measure ourselves, or fignify to others the length of any duration, though at the fame time the world were as full of motion as it is now, but no part of it difpofed into regular and apparently equidiftant revolutions. But the different measures that may be made use of for the account of time, do not at all alter the notion of duration, which is the thing to be measured; no more than the different standards of a foot and a cubit alter the notion of extenfion to those who make use of those different meafures. $25. Our Measure of Time applicable to Duration be fore Time. THE mind having once got fuch a measure of time as the annual revolution of the fun, can apply that meafure to duration, wherein that measure itself, did not exist, and with which, in the reality of its being, it had nothing to do; for fhould one fay, that Abraham was born in the 2712th year of the Julian period, it is altogether as intelligible, as reckoning from the beginning of the world, though there were fo far back no motion of the fun, nor any other motion at all: For though the Julian period be supposed to begin feveral hundred years before there were really either days, nights, or years, marked out by any revolutions of the fun, yet we reckon as right, and thereby measure duration as well, as if really at that time the fun had exifted, and kept the fame ordinary motion it doth now. The idea of duration equal to an annual revolution of the fun, is as eafily applicable in our thoughts to duration, where no fun nor motion was, as the idea of a foot or yard, taken from bodies here, can be applied in our thoughts to distances beyond the confines of the world, where are no bodies at all. § 26. FOR fuppofing it were 5639 miles, or millions of miles, from this place to the remotest body of the univerfe (for being finite, it must be at a certain diftance), as we fuppofe it to be 5639 years from this time to the first exiftence of any body in the beginning of the world; we can, in our thoughts, apply this measure of a year to duration before the creation, or beyond the duration of bodies or motion, as we can this measure of a mile to fpace beyond the utmost bodies; and by the one meafure duration, where there was no motion, as well as by the other measure space in our thoughts, where there is no body. $27. If it be objected to me here, that in this way of explaining of time, I have begged what I fhould not, viz. that the world is neither eternal nor infinite, I answer, that to my prefent purpose it is not needful, in this place, to make ufe of arguments, to evince the world to be finite, both in duration and extenfion; but it being at least as conceivable as the contrary, I have certainly the liberty to fuppofe it, as well as any one hath to fuppofe the contrary; and I doubt not but that every one that will go about it, may easily conceive in his mind the beginning of motion, though not of all duration, and fo may come to a stop and non ultra in his confideration of motion; fo alfo in his thoughts he may fet limits to body, and the extenfion belonging to it, but not to space where no body is; the utmost bounds of space and duration being beyond the reach of thought, as well as the utmoft bounds of number are beyond the largest comprehenfion of the mind; and all for the fame reason, as we shall fee in another place. 28. Eternity. By the fame means, therefore, and from the fame original that we come to have the idea of time, we have alfo that idea which we call eternity; viz. having got the idea of fucceffion and duration, by reflecting on the train of our own ideas caused in us either by the natural appearances of thofe ideas coming conftantly of |