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Show 88 'Duration, and its Jimple Modes. Book If. not keep by us any ftanding unvarying meafure of Duration, which confifls in a conflant /Jeering Succeilion, as we can of certain lengths of Extcnfion, as Inches, Feet, Yards, f!Jc. marked out in permanent parts of Matter. Nothing then could ferve well for a convenient meafure of Time but what has divided the whole length of its Duration into apparently equal Portions, by conf!antly repeated Periods : What Portions of Duration arc not diflinguiOted, orconfidered asdiflinguilhed and meaiitred by fuch Periods, come not fo properly under the Notion of Time, as appears by fuch Phrafes as thefe, viz. hfore all time, and wl;en time jhalt te no mtJre. §.19.The diurnal,and annual RC'Uolutions of tbe Sun,as having been from the beginning of Nature, conf!ant, regular, and univerfally obfervable by all Manl<ind, and fuppofed equal to one another, have been with Reafon made ufe of for t !J< meafure of Duration_. But the diflinction of Days and Years, havmg depended on the mouon of the Sun, it has broucrht this miflake with it, that it has been thought, that Motion and Durati~n were the meafure one of another. For Men in the mcaforiHg; of the te11gtb of tim,, having been accuflomed to the Ideas of Minutes, Hours, Days, Months, Years, f!Jc. wh1ch tbey f~und themfelves upon any mention of T1me or Dura non prefently to dunk on,· all which Portions of Time, were meafured out by the motion of the Heavens, they were apt to confound time and n:totion; or at leaf! to think, that they had a neceifary Connex1on one With anmher: whereas any conf!ant periodical Appea~ ance, or Alterati'?n ·or Idea; in feemingly equidifiant Spaces of Duration, tf conflant and umvcrfally obfcrvable, would have as well difiinguiOted t11e intervals of Time, as thofe that have been made ufe of. For fuppoling the Sun, wluch fome have taken to be a Ftre, had been lighted up at the fame diflance of time that it now every Day comes about to the fame Meridian, and then gone out again abourtwelve hours after, and that in the Space of an annual Revolutwn, 1t had fenfibly increafed in Brightnefs and Heat, and fo decreafed again ; would not fuch regular Appearances fcrve to meafure out the diflances of Duration to all that could obferve it as well without as with Motion. For if the Appearances were conflanr' untverfally obfervabl~, and in equidiflanr Periods, they would ferve Man: kmd for meafure of tt.me as well, were the Motion away. ~: >o. For thefreezmg of Water, or the blowing of a Plant, returning at eqUJdtflant Penods m all parts of the Earrh, would as well ferve Men to reckon the1r Years by,as the Motions of the Sun; and in effect, we fee that fomc People m Amenca counted thetr Y cars by the coming of certain Btrds amongfl them at thetr certam Seafons, and leaving them at others. For •'!) Idea returnmg cowf/antly at equJdiflant Pcriodi, as a Fit of an A· gue; theSenfeofHunger, or Tlurfl; a Smell, or a Tafle; and making it telf umverfally be take~ nonce of, would not fail to me afore out the courfe ofSucceilion, and dtf!mgUtth the dtflances of 7ime. ·And we fee that Men born blmd, count T1me well enough by Years, whofe Revolutions yet they cannot d1f!mgUtfb by Motwns, that they perceive not. And I ask whether a blmd Man, who dif!inguiflted his Years,either by heat of Sum: mer, and cold of W mter ; by the fmell of any Flower of the Spring, or tafleof any Frutt of theAutumn,would not have a better meafure of Time, than the liomans had before the Reformation of their Calendar by Julius C'(f(r,5or rna? hther People, whofe Years, notwithflanding the motion o t •e un, w 11c they pretend to make ufe of, are very irregular· and it a~ds fio iinall difficulty to Chronology, that the exact lengths of tl;e Years t Jat cveral Nations counted by, are hard to be known, they differing very · mud~ Chap. XIV. 'Duration, and its jimp!T! lvfodes. much one from another, and, I think, I may fay all of them, from the prectfe monon of the Sun ; and if the Sun moved from the Creation to the Flood conflanrly 111 the Equator, and fo equally difperfed his light and heat to all the habitable Parts of the Earth,. in Days all of the fame length, Without Its annual vanattons to the Trop1cks, as a late ingenious i).uthor fuppofcs,. I do not think it very ealie to imagine, that (notwithf!anding the monon of the Sun) Men 01ould 111 the AntedilU'Uian World from the beginning count by years, or meafure their time by Periods tl~t had no fenfible marks very obvious to diflinguilh them by. §:21. But, perhaps, it will be faid without a regular Motion, fuch as of the Sun, or fame other, how could It ever be known that fuch Periods were equal? To which I anfwer, the Equality of any other returning ap• pearanccs might be known by the fame way that that of Days was known or prcfumed to be fo at firf!, which was only by judging of them by th~ train of Jd.ai had paifed in Men's Minds in the Intervals whereby they gue.Cfed them to be equal, which was ful!icient to make ritem ferve for :t meafure ; though Iince exacter fearch has difcovered inequality in the di• urnal Revolutions of the Sun, and we kno.w not whether the Annual alfo be not unequal. Thofe yet by their prefum'd and apparent Equality,ferv~ 1lS well to reckon time by, though not to meafure the parts of Duration exactly, as if they could be proved to be exactly equal · we mull therefore carefully diflinguifh lnetwixt Duration it felf, and the meafures we make ufe of to judge of its length. Duration in it felf is to be conlidcred as going on in <Jnc conf!ant equal uniform Courfe; but none of the me..; fures of it we make ufe of can be known to do fo, nor can we be affured that their ailigned Parts <>r Periods are equal in Duration one to another • fOr two fuccef!ive lengths of Duration however meafured, can never ~ demonf!rated to be equal. That wh1ch t~e World ufed fo long, and fo confidently for an exad: meafure of DuratiOn, the motion of the Sun has as I faid, been found in its feveral parts unequal: and though Men hav~ of late made ufe of a Pendulum, as a more fleady and regular Motion, than that of the Sun or (to fpcak more truly) of the Earth; yet if any o~e fl10uld be asked, how hecertamly knows that the two fuccel!ivolivings of a Pendulum are equal, 1t would be very hard to fatisfie himfelf. that ~hey are infullibl'y fo : Iince we cannot be fure, that the Caufe of th;t Motion whicltis unk~own to us, /hall always operate equally; and we are hue, that the Medt~m tn wh1ch the Pendulum moves, is not c<>nfiantly the fame; etther otwhtch varytng, may alter the Equality of fuch Peri• Gds,. and thereby deflroy the certainty and exactnefs of the meafure by Monon, as well as any other Penods of other Appearances, the Notion oF Duration fiill remaining clear, though our meafures of it cannot any of them be demonfirarcd to be exact. Since then no two Portions of Succef.. limr nan ae brought together, it is impoffiblc ever certainly to know their Eqlialicy. AU rhat wecatt do for a meafure of Time, is to take fuch as h~vc continual fuccellive Appearances at feemingly equidiflant Periods ; ofi whtch feeming, Equabry, we JJa'lJe no other m~afure,hut fuch as t/;~ traht of ou, o'"n !tl' "'' have lodged in our Memories, winh the concurrence of other probable Reafons, to perfwadeus of nheirEquality. §. 22. One thing fcems firange to me, that whilft all Men manifeflly meafured liime by the m0tion of the great and vifible Bodies of the World im,e yet fltould be dafined to be the meafure of MotioH ; whereas 'tis o~ "-'ous to every one than reflects ever fo little on it, that to meafure Mo· t10n, SJ>aae.is as neceffary ro be confidcred as Time; and thofe who look a-little !J:rther, will find alfo the bulk of the rhing moved nece/fary to be N taken |
