Physics

第3章

WemaydistinguishgenerallybetweenpredicatingBofAbecauseit(A)isitself，andbecauseitissomethingelse；andparticularlybetweenplacewhichiscommonandinwhichallbodiesare，andthespecialplaceoccupiedprimarilybyeach。Imean，forinstance，thatyouarenowintheheavensbecauseyouareintheairanditisintheheavens；andyouareintheairbecauseyouareontheearth；andsimilarlyontheearthbecauseyouareinthisplacewhichcontainsnomorethanyou。

Nowifplaceiswhatprimarilycontainseachbody，itwouldbealimit，sothattheplacewouldbetheformorshapeofeachbodybywhichthemagnitudeorthematterofthemagnitudeisdefined:forthisisthelimitofeachbody。

If，then，welookatthequestioninthiswaytheplaceofathingisitsform。But，ifweregardtheplaceastheextensionofthemagnitude，itisthematter。Forthisisdifferentfromthemagnitude:

itiswhatiscontainedanddefinedbytheform，asbyaboundingplane。Matterortheindeterminateisofthisnature；whentheboundaryandattributesofaspherearetakenaway，nothingbutthematterisleft。

ThisiswhyPlatointheTimaeussaysthatmatterandspacearethesame；forthe"participant"andspaceareidentical。(Itistrue，indeed，thattheaccounthegivesthereofthe"participant"

isdifferentfromwhathesaysinhisso-called"unwrittenteaching"。Nevertheless，hedididentifyplaceandspace。)ImentionPlatobecause，whileallholdplacetobesomething，healonetriedtosaywhatitis。

Inviewofthesefactsweshouldnaturallyexpecttofinddifficultyindeterminingwhatplaceis，ifindeeditisoneofthesetwothings，matterorform。Theydemandaveryclosescrutiny，especiallyasitisnoteasytorecognizethemapart。

Butitisatanyratenotdifficulttoseethatplacecannotbeeitherofthem。Theformandthematterarenotseparatefromthething，whereastheplacecanbeseparated。Aswepointedout，whereairwas，waterinturncomestobe，theonereplacingtheother；andsimilarlywithotherbodies。Hencetheplaceofathingisneitherapartnorastateofit，butisseparablefromit。Forplaceissupposedtobesomethinglikeavessel-thevesselbeingatransportableplace。Butthevesselisnopartofthething。

Insofarthenasitisseparablefromthething，itisnottheform:quacontaining，itisdifferentfromthematter。

Alsoitisheldthatwhatisanywhereisbothitselfsomethingandthatthereisadifferentthingoutsideit。(Platoofcourse，ifwemaydigress，oughttotelluswhytheformandthenumbersarenotinplace，if"whatparticipates"isplace-whetherwhatparticipatesistheGreatandtheSmallorthematter，ashecalleditinwritingintheTimaeus。)

Further，howcouldabodybecarriedtoitsownplace，ifplacewasthematterortheform?Itisimpossiblethatwhathasnoreferencetomotionorthedistinctionofupanddowncanbeplace。Soplacemustbelookedforamongthingswhichhavethesecharacteristics。

Iftheplaceisinthething(itmustbeifitiseithershapeormatter)placewillhaveaplace:forboththeformandtheindeterminateundergochangeandmotionalongwiththething，andarenotalwaysinthesameplace，butarewherethethingis。Hencetheplacewillhaveaplace。

Further，whenwaterisproducedfromair，theplacehasbeendestroyed，fortheresultingbodyisnotinthesameplace。Whatsortofdestructionthenisthat?

Thisconcludesmystatementofthereasonswhyspacemustbesomething，andagainofthedifficultiesthatmayberaisedaboutitsessentialnature。

Thenextstepwemusttakeistoseeinhowmanysensesonethingissaidtobe"in"another。

(1)Asthefingeris"in"thehandandgenerallythepart"in"thewhole。

(2)Asthewholeis"in"theparts:forthereisnowholeoverandabovetheparts。

(3)Asmanis"in"animalandgenerallyspecies"in"genus。

(4)Asthegenusis"in"thespeciesandgenerallythepartofthespecificform"in"thedefinitionofthespecificform。

(5)Ashealthis"in"thehotandthecoldandgenerallytheform"in"thematter。

(6)AstheaffairsofGreececentre"in"theking，andgenerallyeventscentre"in"theirprimarymotiveagent。

(7)Astheexistenceofathingcentres"initsgoodandgenerally"in"itsend，i。e。in"thatforthesakeofwhich"itexists。

(8)Inthestrictestsenseofall，asathingis"in"avessel，andgenerally"in"place。

Onemightraisethequestionwhetherathingcanbeinitself，orwhethernothingcanbeinitself-everythingbeingeithernowhereorinsomethingelse。

Thequestionisambiguous；wemaymeanthethingquaitselforquasomethingelse。

Whentherearepartsofawhole-theonethatinwhichathingis，theotherthethingwhichisinit-thewholewillbedescribedasbeinginitself。Forathingisdescribedintermsofitsparts，aswellasintermsofthethingasawhole，e。g。amanissaidtobewhitebecausethevisiblesurfaceofhimiswhite，ortobescientificbecausehisthinkingfacultyhasbeentrained。Thejarthenwillnotbeinitselfandthewinewillnotbeinitself。Butthejarofwinewill:forthecontentsandthecontainerarebothpartsofthesamewhole。

Inthissensethen，butnotprimarily，athingcanbeinitself，namely，as"white"isinbody(forthevisiblesurfaceisinbody)，andscienceisinthemind。

Itisfromthese，whichare"parts"(inthesenseatleastofbeing"in"theman)，thatthemaniscalledwhite，&c。Butthejarandthewineinseparationarenotpartsofawhole，thoughtogethertheyare。Sowhenthereareparts，athingwillbeinitself，as"white"isinmanbecauseitisinbody，andinbodybecauseitresidesinthevisiblesurface。Wecannotgofurtherandsaythatitisinsurfaceinvirtueofsomethingotherthanitself。(Yetitisnotinitself:thoughtheseareinawaythesamething，)theydifferinessence，eachhavingaspecialnatureandcapacity，"surface"and"white"。

Thusifwelookatthematterinductivelywedonotfindanythingtobe"in"itselfinanyofthesensesthathavebeendistinguished；

anditcanbeseenbyargumentthatitisimpossible。Foreachoftwothingswillhavetobeboth，e。g。thejarwillhavetobebothvesselandwine，andthewinebothwineandjar，ifitispossibleforathingtobeinitself；sothat，howevertrueitmightbethattheywereineachother，thejarwillreceivethewineinvirtuenotofitsbeingwinebutofthewine"sbeingwine，andthewinewillbeinthejarinvirtuenotofitsbeingajarbutofthejar"sbeingajar。Nowthattheyaredifferentinrespectoftheiressenceisevident；for"thatinwhichsomethingis"and"thatwhichisinit"wouldbedifferentlydefined。

Norisitpossibleforathingtobeinitselfevenincidentally:

fortwothingswouldatthesametimeinthesamething。Thejarwouldbeinitself-ifathingwhosenatureitistoreceivecanbeinitself；andthatwhichitreceives，namely(ifwine)wine，willbeinit。

Obviouslythenathingcannotbeinitselfprimarily。

Zeno"sproblem-thatifPlaceissomethingitmustbeinsomething-isnotdifficulttosolve。Thereisnothingtopreventthefirstplacefrombeing"in"somethingelse-notindeedinthatas"in"place，butashealthis"in"thehotasapositivedeterminationofitorasthehotis"in"bodyasanaffection。Soweescapetheinfiniteregress。

Anotherthingisplain:sincethevesselisnopartofwhatisinit(whatcontainsinthestrictsenseisdifferentfromwhatiscontained)，placecouldnotbeeitherthematterortheformofthethingcontained，butmustdifferent-forthelatter，boththematterandtheshape，arepartsofwhatiscontained。

Thisthenmayserveasacriticalstatementofthedifficultiesinvolved。

Whatthenafterallisplace?Theanswertothisquestionmaybeelucidatedasfollows。

Letustakeforgrantedaboutitthevariouscharacteristicswhicharesupposedcorrectlytobelongtoitessentially。Weassumethen-

(1)Placeiswhatcontainsthatofwhichitistheplace。

(2)Placeisnopartofthething。

(3)Theimmediateplaceofathingisneitherlessnorgreaterthanthething。

(4)Placecanbeleftbehindbythethingandisseparable。Inaddition:

(5)Allplaceadmitsofthedistinctionofupanddown，andeachofthebodiesisnaturallycarriedtoitsappropriateplaceandreststhere，andthismakestheplaceeitherupordown。

Havinglaidthesefoundations，wemustcompletethetheory。Weoughttotrytomakeourinvestigationsuchaswillrenderanaccountofplace，andwillnotonlysolvethedifficultiesconnectedwithit，butwillalsoshowthattheattributessupposedtobelongtoitdoreallybelongtoit，andfurtherwillmakeclearthecauseofthetroubleandofthedifficultiesaboutit。Suchisthemostsatisfactorykindofexposition。

Firstthenwemustunderstandthatplacewouldnothavebeenthoughtof，iftherehadnotbeenaspecialkindofmotion，namelythatwithrespecttoplace。Itischieflyforthisreasonthatwesupposetheheavenalsotobeinplace，becauseitisinconstantmovement。Ofthiskindofchangetherearetwospecies-locomotionontheonehandand，ontheother，increaseanddiminution。Forthesetooinvolvevariationofplace:whatwastheninthisplacehasnowinturnchangedtowhatislargerorsmaller。

Again，whenwesayathingis"moved"，thepredicateeither(1)

belongstoitactually，invirtueofitsownnature，or(2)invirtueofsomethingconjoinedwithit。Inthelattercaseitmaybeeither(a)somethingwhichbyitsownnatureiscapableofbeingmoved，e。g。thepartsofthebodyorthenailintheship，or(b)

somethingwhichisnotinitselfcapableofbeingmoved，butisalwaysmovedthroughitsconjunctionwithsomethingelse，as"whiteness"or"science"。Thesehavechangedtheirplaceonlybecausethesubjectstowhichtheybelongdoso。

Wesaythatathingisintheworld，inthesenseofinplace，becauseitisintheair，andtheairisintheworld；andwhenwesayitisintheair，wedonotmeanitisineverypartoftheair，butthatitisintheairbecauseoftheoutersurfaceoftheairwhichsurroundsit；forifalltheairwereitsplace，theplaceofathingwouldnotbeequaltothething-whichitissupposedtobe，andwhichtheprimaryplaceinwhichathingisactuallyis。

Whenwhatsurrounds，then，isnotseparatefromthething，butisincontinuitywithit，thethingissaidtobeinwhatsurroundsit，notinthesenseofinplace，butasapartinawhole。Butwhenthethingisseparateandincontact，itisimmediately"in"theinnersurfaceofthesurroundingbody，andthissurfaceisneitherapartofwhatisinitnoryetgreaterthanitsextension，butequaltoit；fortheextremitiesofthingswhichtoucharecoincident。

Further，ifonebodyisincontinuitywithanother，itisnotmovedinthatbutwiththat。Ontheotherhanditismovedinthatifitisseparate。Itmakesnodifferencewhetherwhatcontainsismovedornot。

Again，whenitisnotseparateitisdescribedasapartinawhole，asthepupilintheeyeorthehandinthebody:whenitisseparate，asthewaterinthecaskorthewineinthejar。Forthehandismovedwiththebodyandthewaterinthecask。

Itwillnowbeplainfromtheseconsiderationswhatplaceis。

Therearejustfourthingsofwhichplacemustbeone-theshape，orthematter，orsomesortofextensionbetweentheboundingsurfacesofthecontainingbody，orthisboundaryitselfifitcontainsnoextensionoverandabovethebulkofthebodywhichcomestobeinit。

Threeoftheseitobviouslycannotbe:

(1)Theshapeissupposedtobeplacebecauseitsurrounds，fortheextremitiesofwhatcontainsandofwhatiscontainedarecoincident。Boththeshapeandtheplace，itistrue，areboundaries。Butnotofthesamething:theformistheboundaryofthething，theplaceistheboundaryofthebodywhichcontainsit。

(2)Theextensionbetweentheextremitiesisthoughttobesomething，becausewhatiscontainedandseparatemayoftenbechangedwhilethecontainerremainsthesame(aswatermaybepouredfromavessel)-theassumptionbeingthattheextensionissomethingoverandabovethebodydisplaced。Butthereisnosuchextension。Oneofthebodieswhichchangeplacesandarenaturallycapableofbeingincontactwiththecontainerfallsinwhicheveritmaychancetobe。

Iftherewereanextensionwhichweresuchastoexistindependentlyandbepermanent，therewouldbeaninfinityofplacesinthesamething。Forwhenthewaterandtheairchangeplaces，alltheportionsofthetwotogetherwillplaythesamepartinthewholewhichwaspreviouslyplayedbyallthewaterinthevessel；atthesametimetheplacetoowillbeundergoingchange；sothattherewillbeanotherplacewhichistheplaceoftheplace，andmanyplaceswillbecoincident。Thereisnotadifferentplaceofthepart，inwhichitismoved，whenthewholevesselchangesitsplace:itisalwaysthesame:foritisinthe(proximate)placewheretheyarethattheairandthewater(orthepartsofthewater)succeedeachother，notinthatplaceinwhichtheycometobe，whichispartoftheplacewhichistheplaceofthewholeworld。

(3)Thematter，too，mightseemtobeplace，atleastifweconsideritinwhatisatrestandisthusseparatebutincontinuity。Forjustasinchangeofqualitythereissomethingwhichwasformerlyblackandisnowwhite，orformerlysoftandnowhard-thisisjustwhywesaythatthematterexists-soplace，becauseitpresentsasimilarphenomenon，isthoughttoexist-onlyintheonecasewesaysobecausewhatwasairisnowwater，intheotherbecausewhereairformerlywasthereaisnowwater。Butthematter，aswesaidbefore，isneitherseparablefromthethingnorcontainsit，whereasplacehasbothcharacteristics。

Well，then，ifplaceisnoneofthethree-neithertheformnorthematternoranextensionwhichisalwaysthere，differentfrom，andoverandabove，theextensionofthethingwhichisdisplaced-placenecessarilyistheoneofthefourwhichisleft，namely，theboundaryofthecontainingbodyatwhichitisincontactwiththecontainedbody。(Bythecontainedbodyismeantwhatcanbemovedbywayoflocomotion。)

Placeisthoughttobesomethingimportantandhardtograsp，bothbecausethematterandtheshapepresentthemselvesalongwithit，andbecausethedisplacementofthebodythatismovedtakesplaceinastationarycontainer，foritseemspossiblethatthereshouldbeanintervalwhichisotherthanthebodieswhicharemoved。Theair，too，whichisthoughttobeincorporeal，contributessomethingtothebelief:itisnotonlytheboundariesofthevesselwhichseemtobeplace，butalsowhatisbetweenthem，regardedasempty。Just，infact，asthevesselistransportableplace，soplaceisanon-portablevessel。Sowhenwhatiswithinathingwhichismoved，ismovedandchangesitsplace，asaboatonariver，whatcontainsplaysthepartofavesselratherthanthatofplace。Placeontheotherhandisratherwhatismotionless:soitisratherthewholeriverthatisplace，becauseasawholeitismotionless。

Henceweconcludethattheinnermostmotionlessboundaryofwhatcontainsisplace。

Thisexplainswhythemiddleoftheheavenandthesurfacewhichfacesusoftherotatingsystemareheldtobe"up"and"down"inthestrictandfullestsenseforallmen:fortheoneisalwaysatrest，whiletheinnersideoftherotatingbodyremainsalwayscoincidentwithitself。Hencesincethelightiswhatisnaturallycarriedup，andtheheavywhatiscarrieddown，theboundarywhichcontainsinthedirectionofthemiddleoftheuniverse，andthemiddleitself，aredown，andthatwhichcontainsinthedirectionoftheoutermostpartoftheuniverse，andtheoutermostpartitself，areup。

Forthisreason，too，placeisthoughttobeakindofsurface，andasitwereavessel，i。e。acontainerofthething。

Further，placeiscoincidentwiththething，forboundariesarecoincidentwiththebounded。

Ifthenabodyhasanotherbodyoutsideitandcontainingit，itisinplace，andifnot，not。Thatiswhy，evenifthereweretobewaterwhichhadnotacontainer，thepartsofit，ontheonehand，willbemoved(foronepartiscontainedinanother)，while，ontheotherhand，thewholewillbemovedinonesense，butnotinanother。Forasawholeitdoesnotsimultaneouslychangeitsplace，thoughitwillbemovedinacircle:forthisplaceistheplaceofitsparts。(Somethingsaremoved，notupanddown，butinacircle；

othersupanddown，suchthingsnamelyasadmitofcondensationandrarefaction。)

Aswasexplained，somethingsarepotentiallyinplace，othersactually。So，whenyouhaveahomogeneoussubstancewhichiscontinuous，thepartsarepotentiallyinplace:whenthepartsareseparated，butincontact，likeaheap，theyareactuallyinplace。

Again，(1)somethingsareperseinplace，namelyeverybodywhichismovableeitherbywayoflocomotionorbywayofincreaseispersesomewhere，buttheheaven，ashasbeensaid，isnotanywhereasawhole，norinanyplace，ifatleast，aswemustsuppose，nobodycontainsit。Onthelineonwhichitismoved，itspartshaveplace:

foreachiscontiguousthenext。

But(2)otherthingsareinplaceindirectly，throughsomethingconjoinedwiththem，asthesoulandtheheaven。Thelatteris，inaway，inplace，forallitspartsare:forontheorbonepartcontainsanother。Thatiswhytheupperpartismovedinacircle，whiletheAllisnotanywhere。Forwhatissomewhereisitselfsomething，andtheremustbealongsideitsomeotherthingwhereinitisandwhichcontainsit。ButalongsidetheAllortheWholethereisnothingoutsidetheAll，andforthisreasonallthingsareintheheaven；fortheheaven，wemaysay，istheAll。Yettheirplaceisnotthesameastheheaven。Itispartofit，theinnermostpartofit，whichisincontactwiththemovablebody；andforthisreasontheearthisinwater，andthisintheair，andtheairintheaether，andtheaetherinheaven，butwecannotgoonandsaythattheheavenisinanythingelse。

Itisclear，too，fromtheseconsiderationsthatalltheproblemswhichwereraisedaboutplacewillbesolvedwhenitisexplainedinthisway:

(1)Thereisnonecessitythattheplaceshouldgrowwiththebodyinit，(2)Northatapointshouldhaveaplace，(3)Northattwobodiesshouldbeinthesameplace，(4)Northatplaceshouldbeacorporealinterval:forwhatisbetweentheboundariesoftheplaceisanybodywhichmaychancetobethere，notanintervalinbody。

Further，(5)placeisalsosomewhere，notinthesenseofbeinginaplace，butasthelimitisinthelimited；fornoteverythingthatisisinplace，butonlymovablebody。

Also(6)itisreasonablethateachkindofbodyshouldbecarriedtoitsownplace。Forabodywhichisnextintheseriesandincontact(notbycompulsion)isakin，andbodieswhichareuniteddonotaffecteachother，whilethosewhichareincontactinteractoneachother。

Nor(7)isitwithoutreasonthateachshouldremainnaturallyinitsproperplace。Forthisparthasthesamerelationtoitsplace，asaseparableparttoitswhole，aswhenonemovesapartofwaterorair:so，too，airisrelatedtowater，fortheoneislikematter，theotherform-wateristhematterofair，airasitweretheactualityofwater，forwaterispotentiallyair，whileairispotentiallywater，thoughinanotherway。

Thesedistinctionswillbedrawnmorecarefullylater。Onthepresentoccasionitwasnecessarytorefertothem:whathasnowbeenstatedobscurelywillthenbemademoreclear。Ifthematterandthefulfilmentarethesamething(forwaterisboth，theonepotentially，theothercompletely)，waterwillberelatedtoairinawayasparttowhole。Thatiswhythesehavecontact:itisorganicunionwhenbothbecomeactuallyone。

Thisconcludesmyaccountofplace-bothofitsexistenceandofitsnature。

Theinvestigationofsimilarquestionsaboutthevoid，also，mustbeheldtobelongtothephysicist-namelywhetheritexistsornot，andhowitexistsorwhatitis-justasaboutplace。Theviewstakenofitinvolveargumentsbothforandagainst，inmuchthesamesortofway。Forthosewhoholdthatthevoidexistsregarditasasortofplaceorvesselwhichissupposedtobe"full"whenitholdsthebulkwhichitiscapableofcontaining，"void"whenitisdeprivedofthat-asif"void"and"full"and"place"denotedthesamething，thoughtheessenceofthethreeisdifferent。

Wemustbegintheinquirybyputtingdowntheaccountgivenbythosewhosaythatitexists，thentheaccountofthosewhosaythatitdoesnotexist，andthirdthecurrentviewonthesequestions。

Thosewhotrytoshowthatthevoiddoesnotexistdonotdisprovewhatpeoplereallymeanbyit，butonlytheirerroneouswayofspeaking；thisistrueofAnaxagorasandofthosewhorefutetheexistenceofthevoidinthisway。Theymerelygiveaningeniousdemonstrationthatairissomething——bystrainingwine-skinsandshowingtheresistanceoftheair，andbycuttingitoffinclepsydras。Butpeoplereallymeanthatthereisanemptyintervalinwhichthereisnosensiblebody。Theyholdthateverythingwhichisinbodyisbodyandsaythatwhathasnothinginitatallisvoid(sowhatisfullofairisvoid)。Itisnotthentheexistenceofairthatneedstobeproved，butthenon-existenceofaninterval，differentfromthebodies，eitherseparableoractual-anintervalwhichdividesthewholebodysoastobreakitscontinuity，asDemocritusandLeucippushold，andmanyotherphysicists-orevenperhapsassomethingwhichisoutsidethewholebody，whichremainscontinuous。

Thesepeople，then，havenotreachedeventhethresholdoftheproblem，butratherthosewhosaythatthevoidexists。

(1)Theyargue，foronething，thatchangeinplace(i。e。locomotionandincrease)wouldnotbe。Foritismaintainedthatmotionwouldseemnottoexist，iftherewerenovoid，sincewhatisfullcannotcontainanythingmore。Ifitcould，andthereweretwobodiesinthesameplace，itwouldalsobetruethatanynumberofbodiescouldbetogether；foritisimpossibletodrawalineofdivisionbeyondwhichthestatementwouldbecomeuntrue。Ifthiswerepossible，itwouldfollowalsothatthesmallestbodywouldcontainthegreatest；for"manyalittlemakesamickle":thusifmanyequalbodiescanbetogether，soalsocanmanyunequalbodies。

Melissus，indeed，infersfromtheseconsiderationsthattheAllisimmovable；forifitweremovedtheremust，hesays，bevoid，butvoidisnotamongthethingsthatexist。

Thisargument，then，isonewayinwhichtheyshowthatthereisavoid。

(2)Theyreasonfromthefactthatsomethingsareobservedtocontractandbecompressed，aspeoplesaythatacaskwillholdthewinewhichformerlyfilledit，alongwiththeskinsintowhichthewinehasbeendecanted，whichimpliesthatthecompressedbodycontractsintothevoidspresentinit。

Again(3)increase，too，isthoughttotakealwaysbymeansofvoid，fornutrimentisbody，anditisimpossiblefortwobodiestobetogether。Aproofofthistheyfindalsoinwhathappenstoashes，whichabsorbasmuchwaterastheemptyvessel。

ThePythagoreans，too，(4)heldthatvoidexistsandthatitenterstheheavenitself，whichasitwereinhalesit，fromtheinfiniteair。Furtheritisthevoidwhichdistinguishesthenaturesofthings，asifitwerelikewhatseparatesanddistinguishesthetermsofaseries。Thisholdsprimarilyinthenumbers，forthevoiddistinguishestheirnature。

These，then，andsomany，arethemaingroundsonwhichpeoplehavearguedforandagainsttheexistenceofthevoid。

Asasteptowardssettlingwhichviewistrue，wemustdeterminethemeaningofthename。

Thevoidisthoughttobeplacewithnothinginit。Thereasonforthisisthatpeopletakewhatexiststobebody，andholdthatwhileeverybodyisinplace，voidisplaceinwhichthereisnobody，sothatwherethereisnobody，theremustbevoid。

Everybody，again，theysupposetobetangible；andofthisnatureiswhateverhasweightorlightness。

Hence，byasyllogism，whathasnothingheavyorlightinit，isvoid。

Thisresult，then，asIhavesaid，isreachedbysyllogism。Itwouldbeabsurdtosupposethatthepointisvoid；forthevoidmustbeplacewhichhasinitanintervalintangiblebody。

Butatalleventsweobservethenthatinonewaythevoidisdescribedaswhatisnotfullofbodyperceptibletotouch；andwhathasheavinessandlightnessisperceptibletotouch。Sowewouldraisethequestion:whatwouldtheysayofanintervalthathascolourorsound-isitvoidornot?Clearlytheywouldreplythatifitcouldreceivewhatistangibleitwasvoid，andifnot，not。

Inanotherwayvoidisthatinwhichthereisno"this"orcorporealsubstance。Sosomesaythatthevoidisthematterofthebody(theyidentifytheplace，too，withthis)，andinthistheyspeakincorrectly；forthematterisnotseparablefromthethings，buttheyareinquiringaboutthevoidasaboutsomethingseparable。

Sincewehavedeterminedthenatureofplace，andvoidmust，ifitexists，beplacedeprivedofbody，andwehavestatedbothinwhatsenseplaceexistsandinwhatsenseitdoesnot，itisplainthatonthisshowingvoiddoesnotexist，eitherunseparatedorseparated；thevoidismeanttobe，notbodybutratheranintervalinbody。Thisiswhythevoidisthoughttobesomething，viz。becauseplaceis，andforthesamereasons。Forthefactofmotioninrespectofplacecomestotheaidbothofthosewhomaintainthatplaceissomethingoverandabovethebodiesthatcometooccupyit，andofthosewhomaintainthatthevoidissomething。Theystatethatthevoidistheconditionofmovementinthesenseofthatinwhichmovementtakesplace；andthiswouldbethekindofthingthatsomesayplaceis。

Butthereisnonecessityfortherebeingavoidifthereismovement。Itisnotintheleastneededasaconditionofmovementingeneral，forareasonwhich，incidentally，escapedMelissus；viz。

thatthefullcansufferqualitativechange。

Butnotevenmovementinrespectofplaceinvolvesavoid；forbodiesmaysimultaneouslymakeroomforoneanother，thoughthereisnointervalseparateandapartfromthebodiesthatareinmovement。

Andthisisplainevenintherotationofcontinuousthings，asinthatofliquids。

Andthingscanalsobecompressednotintoavoidbutbecausetheysqueezeoutwhatiscontainedinthem(as，forinstance，whenwateriscompressedtheairwithinitissqueezedout)；andthingscanincreaseinsizenotonlybytheentranceofsomethingbutalsobyqualitativechange；e。g。ifwaterweretobetransformedintoair。

Ingeneral，boththeargumentaboutincreaseofsizeandthataboutwaterpouredontotheashesgetintheirownway。Foreithernotanyandeverypartofthebodyisincreased，orbodiesmaybeincreasedotherwisethanbytheadditionofbody，ortheremaybetwobodiesinthesameplace(inwhichcasetheyareclaimingtosolveaquitegeneraldifficulty，butarenotprovingtheexistenceofvoid)，orthewholebodymustbevoid，ifitisincreasedineverypartandisincreasedbymeansofvoid。Thesameargumentappliestotheashes。

Itisevident，then，thatitiseasytorefutetheargumentsbywhichtheyprovetheexistenceofthevoid。

Letusexplainagainthatthereisnovoidexistingseparately，assomemaintain。Ifeachofthesimplebodieshasanaturallocomotion，e。g。fireupwardandearthdownwardandtowardsthemiddleoftheuniverse，itisclearthatitcannotbethevoidthatistheconditionoflocomotion。What，then，willthevoidbetheconditionof?Itisthoughttobetheconditionofmovementinrespectofplace，anditisnottheconditionofthis。

Again，ifvoidisasortofplacedeprivedofbody，whenthereisavoidwherewillabodyplacedinitmoveto?Itcertainlycannotmoveintothewholeofthevoid。Thesameargumentappliesasagainstthosewhothinkthatplaceissomethingseparate，intowhichthingsarecarried；viz。howwillwhatisplacedinitmove，orrest?Muchthesameargumentwillapplytothevoidastothe"up"and"down"inplace，asisnaturalenoughsincethosewhomaintaintheexistenceofthevoidmakeitaplace。

Andinwhatwaywillthingsbepresenteitherinplace-orinthevoid?Fortheexpectedresultdoesnottakeplacewhenabodyisplacedasawholeinaplaceconceivedofasseparateandpermanent；

forapartofit，unlessitbeplacedapart，willnotbeinaplacebutinthewhole。Further，ifseparateplacedoesnotexist，neitherwillvoid。

Ifpeoplesaythatthevoidmustexist，asbeingnecessaryifthereistobemovement，whatratherturnsouttobethecase，ifonethematter，istheopposite，thatnotasinglethingcanbemovedifthereisavoid；foraswiththosewhoforalikereasonsaytheearthisatrest，so，too，inthevoidthingsmustbeatrest；

forthereisnoplacetowhichthingscanmovemoreorlessthantoanother；sincethevoidinsofarasitisvoidadmitsnodifference。

Thesecondreasonisthis:allmovementiseithercompulsoryoraccordingtonature，andifthereiscompulsorymovementtheremustalsobenatural(forcompulsorymovementiscontrarytonature，andmovementcontrarytonatureisposteriortothataccordingtonature，sothatifeachofthenaturalbodieshasnotanaturalmovement，noneoftheothermovementscanexist)；buthowcantherebenaturalmovementifthereisnodifferencethroughoutthevoidortheinfinite?Forinsofarasitisinfinite，therewillbenoupordownormiddle，andinsofarasitisavoid，updiffersnowhitfromdown；forasthereisnodifferenceinwhatisnothing，thereisnoneinthevoid(forthevoidseemstobeanon-existentandaprivationofbeing)，butnaturallocomotionseemstobedifferentiated，sothatthethingsthatexistbynaturemustbedifferentiated。Either，then，nothinghasanaturallocomotion，orelsethereisnovoid。

Further，inpointoffactthingsthatarethrownmovethoughthatwhichgavethemtheirimpulseisnottouchingthem，eitherbyreasonofmutualreplacement，assomemaintain，orbecausetheairthathasbeenpushedpushesthemwithamovementquickerthanthenaturallocomotionoftheprojectilewherewithitmovestoitsproperplace。

Butinavoidnoneofthesethingscantakeplace，norcananythingbemovedsaveasthatwhichiscarriedismoved。

Further，noonecouldsaywhyathingoncesetinmotionshouldstopanywhere；forwhyshoulditstophereratherthanhere?Sothatathingwilleitherbeatrestormustbemovedadinfinitum，unlesssomethingmorepowerfulgetinitsway。

Further，thingsarenowthoughttomoveintothevoidbecauseityields；butinavoidthisqualityispresentequallyeverywhere，sothatthingsshouldmoveinalldirections。

Further，thetruthofwhatweassertisplainfromthefollowingconsiderations。Weseethesameweightorbodymovingfasterthananotherfortworeasons，eitherbecausethereisadifferenceinwhatitmovesthrough，asbetweenwater，air，andearth，orbecause，otherthingsbeingequal，themovingbodydiffersfromtheotherowingtoexcessofweightoroflightness。

Nowthemediumcausesadifferencebecauseitimpedesthemovingthing，mostofallifitismovingintheoppositedirection，butinasecondarydegreeevenifitisatrest；andespeciallyamediumthatisnoteasilydivided，i。e。amediumthatissomewhatdense。A，then，willmovethroughBintimeG，andthroughD，whichisthinner，intimeE(ifthelengthofBisegualtoD)，inproportiontothedensityofthehinderingbody。ForletBbewaterandDair；

thenbysomuchasairisthinnerandmoreincorporealthanwater，A

willmovethroughDfasterthanthroughB。Letthespeedhavethesameratiotothespeed，then，thatairhastowater。Thenifairistwiceasthin，thebodywilltraverseBintwicethetimethatitdoesD，andthetimeGwillbetwicethetimeE。Andalways，bysomuchasthemediumismoreincorporealandlessresistantandmoreeasilydivided，thefasterwillbethemovement。

Nowthereisnoratioinwhichthevoidisexceededbybody，asthereisnoratioof0toanumber。Forif4exceeds3by1，and2

bymorethan1，and1bystillmorethanitexceeds2，stillthereisnoratiobywhichitexceeds0；forthatwhichexceedsmustbedivisibleintotheexcess+thatwhichisexceeded，sothatwillbewhatitexceeds0by+0。Forthisreason，too，alinedoesnotexceedapointunlessitiscomposedofpoints！Similarlythevoidcanbearnoratiotothefull，andthereforeneithercanmovementthroughtheonetomovementthroughtheother，butifathingmovesthroughthethickestmediumsuchandsuchadistanceinsuchandsuchatime，itmovesthroughthevoidwithaspeedbeyondanyratio。ForletZbevoid，equalinmagnitudetoBandtoD。ThenifAistotraverseandmovethroughitinacertaintime，H，atimelessthanE，however，thevoidwillbearthisratiotothefull。ButinatimeequaltoH，A

willtraversethepartOofA。AnditwillsurelyalsotraverseinthattimeanysubstanceZwhichexceedsairinthicknessintheratiowhichthetimeEbearstothetimeH。ForifthebodyZbeasmuchthinnerthanDasEexceedsH，A，ifitmovesthroughZ，willtraverseitinatimeinversetothespeedofthemovement，i。e。inatimeequaltoH。If，then，thereisnobodyinZ，AwilltraverseZstillmorequickly。ButwesupposedthatitstraverseofZwhenZ

wasvoidoccupiedthetimeH。SothatitwilltraverseZinanequaltimewhetherZbefullorvoid。Butthisisimpossible。Itisplain，then，thatifthereisatimeinwhichitwillmovethroughanypartofthevoid，thisimpossibleresultwillfollow:itwillbefoundtotraverseacertaindistance，whetherthisbefullorvoid，inanequaltime；fortherewillbesomebodywhichisinthesameratiototheotherbodyasthetimeistothetime。

Tosumthematterup，thecauseofthisresultisobvious，viz。thatbetweenanytwomovementsthereisaratio(fortheyoccupytime，andthereisaratiobetweenanytwotimes，solongasbotharefinite)，butthereisnoratioofvoidtofull。

Thesearetheconsequencesthatresultfromadifferenceinthemedia；thefollowingdependuponanexcessofonemovingbodyoveranother。Weseethatbodieswhichhaveagreaterimpulseeitherofweightoroflightness，iftheyarealikeinotherrespects，movefasteroveranequalspace，andintheratiowhichtheirmagnitudesbeartoeachother。Thereforetheywillalsomovethroughthevoidwiththisratioofspeed。Butthatisimpossible；forwhyshouldonemovefaster?(Inmovingthroughplenaitmustbeso；forthegreaterdividesthemfasterbyitsforce。Foramovingthingcleavesthemediumeitherbyitsshape，orbytheimpulsewhichthebodythatiscarriedalongorisprojectedpossesses。)Thereforeallwillpossessequalvelocity。Butthisisimpossible。

Itisevidentfromwhathasbeensaid，then，that，ifthereisavoid，aresultfollowswhichistheveryoppositeofthereasonforwhichthosewhobelieveinavoidsetitup。Theythinkthatifmovementinrespectofplaceistoexist，thevoidcannotexist，separatedallbyitself；butthisisthesameastosaythatplaceisaseparatecavity；andthishasalreadybeenstatedtobeimpossible。

Butevenifweconsideritonitsownmeritstheso-calledvacuumwillbefoundtobereallyvacuous。Foras，ifoneputsacubeinwater，anamountofwaterequaltothecubewillbedisplaced；sotooinair；buttheeffectisimperceptibletosense。Andindeedalwaysinthecaseofanybodythatcanbedisplaced，must，ifitisnotcompressed，bedisplacedinthedirectioninwhichitisitsnaturetobedisplaced-alwayseitherdown，ifitslocomotionisdownwardsasinthecaseofearth，orup，ifitisfire，orinbothdirections-whateverbethenatureoftheinsertedbody。Nowinthevoidthisisimpossible；foritisnotbody；thevoidmusthavepenetratedthecubetoadistanceequaltothatwhichthisportionofvoidformerlyoccupiedinthevoid，justasifthewaterorairhadnotbeendisplacedbythewoodencube，buthadpenetratedrightthroughit。

Butthecubealsohasamagnitudeequaltothatoccupiedbythevoid；amagnitudewhich，ifitisalsohotorcold，orheavyorlight，isnonethelessdifferentinessencefromallitsattributes，evenifitisnotseparablefromthem；Imeanthevolumeofthewoodencube。

Sothatevenifitwereseparatedfromeverythingelseandwereneitherheavynorlight，itwilloccupyanequalamountofvoid，andfillthesameplace，asthepartofplaceorofthevoidequaltoitself。Howthenwillthebodyofthecubedifferfromthevoidorplacethatisequaltoit?Andiftherecanbetwosuchthings，whycannottherebeanynumbercoinciding?

This，then，isoneabsurdandimpossibleimplicationofthetheory。Itisalsoevidentthatthecubewillhavethissamevolumeevenifitisdisplaced，whichisanattributepossessedbyallotherbodiesalso。Thereforeifthisdiffersinnorespectfromitsplace，whyneedweassumeaplaceforbodiesoverandabovethevolumeofeach，iftheirvolumebeconceivedofasfreefromattributes?Itcontributesnothingtothesituationifthereisanequalintervalattachedtoitaswell。[Furtheritoughttobeclearbythestudyofmovingthingswhatsortofthingvoidis。Butinfactitisfoundnowhereintheworld。Forairissomething，thoughitdoesnotseemtobeso-nor，forthatmatter，wouldwater，iffishesweremadeofiron；forthediscriminationofthetangibleisbytouch。]

Itisclear，then，fromtheseconsiderationsthatthereisnoseparatevoid。

Therearesomewhothinkthattheexistenceofrarityanddensityshowsthatthereisavoid。Ifrarityanddensitydonotexist，theysay，neithercanthingscontractandbecompressed。Butifthiswerenottotakeplace，eithertherewouldbenomovementatall，ortheuniversewouldbulge，asXuthussaid，orairandwatermustalwayschangeintoequalamounts(e。g。ifairhasbeenmadeoutofacupfulofwater，atthesametimeoutofanequalamountofairacupfulofwatermusthavebeenmade)，orvoidmustnecessarilyexist；forcompressionandexpansioncannottakeplaceotherwise。

Now，iftheymeanbytherarethatwhichhasmanyvoidsexistingseparately，itisplainthatifvoidcannotexistseparateanymorethanaplacecanexistwithanextensionalltoitself，neithercantherareexistinthissense。Butiftheymeanthatthereisvoid，notseparatelyexistent，butstillpresentintherare，thisislessimpossible，yet，first，thevoidturnsoutnottobeaconditionofallmovement，butonlyofmovementupwards(fortherareislight，whichisthereasonwhytheysayfireisrare)；second，thevoidturnsouttobeaconditionofmovementnotasthatinwhichittakesplace，butinthatthevoidcarriesthingsupasskinsbybeingcarriedupthemselvescarryupwhatiscontinuouswiththem。Yethowcanvoidhavealocalmovementoraplace?Forthusthatintowhichvoidmovesistillthenvoidofavoid。

Again，howwilltheyexplain，inthecaseofwhatisheavy，itsmovementdownwards?Anditisplainthatiftherarerandmorevoidathingisthequickeritwillmoveupwards，ifitwerecompletelyvoiditwouldmovewithamaximumspeed！Butperhapseventhisisimpossible，thatitshouldmoveatall；thesamereasonwhichshowedthatinthevoidallthingsareincapableofmovingshowsthatthevoidcannotmove，viz。thefactthatthespeedsareincomparable。

Sincewedenythatavoidexists，butfortheresttheproblemhasbeentrulystated，thateithertherewillbenomovement，ifthereisnottobecondensationandrarefaction，ortheuniversewillbulge，oratransformationofwaterintoairwillalwaysbebalancedbyanequaltransformationofairintowater(foritisclearthattheairproducedfromwaterisbulkierthanthewater):itisnecessarytherefore，ifcompressiondoesnotexist，eitherthatthenextportionwillbepushedoutwardsandmaketheoutermostpartbulge，orthatsomewhereelsetheremustbeanequalamountofwaterproducedoutofair，sothattheentirebulkofthewholemaybeequal，orthatnothingmoves。Forwhenanythingisdisplacedthiswillalwayshappen，unlessitcomesroundinacircle；butlocomotionisnotalwayscircular，butsometimesinastraightline。

Thesethenarethereasonsforwhichtheymightsaythatthereisavoid；ourstatementisbasedontheassumptionthatthereisasinglematterforcontraries，hotandcoldandtheothernaturalcontrarieties，andthatwhatexistsactuallyisproducedfromapotentialexistent，andthatmatterisnotseparablefromthecontrariesbutitsbeingisdifferent，andthatasinglemattermayserveforcolourandheatandcold。

Thesamematteralsoservesforbothalargeandasmallbody。

Thisisevident；forwhenairisproducedfromwater，thesamematterhasbecomesomethingdifferent，notbyacquiringanadditiontoit，buthasbecomeactuallywhatitwaspotentially，and，again，waterisproducedfromairinthesameway，thechangebeingsometimesfromsmallnesstogreatness，andsometimesfromgreatnesstosmallness。Similarly，therefore，ifairwhichislargeinextentcomestohaveasmallervolume，orbecomesgreaterfrombeingsmaller，itisthematterwhichispotentiallyboththatcomestobeeachofthetwo。

Forasthesamematterbecomeshotfrombeingcold，andcoldfrombeinghot，becauseitwaspotentiallyboth，sotoofromhotitcanbecomemorehot，thoughnothinginthematterhasbecomehotthatwasnothotwhenthethingwaslesshot；justas，ifthearcorcurveofagreatercirclebecomesthatofasmaller，whetheritremainsthesameorbecomesadifferentcurve，convexityhasnotcometoexistinanythingthatwasnotconvexbutstraight(fordifferencesofdegreedonotdependonanintermissionofthequality)；norcanwegetanyportionofaflame，inwhichbothheatandwhitenessarenotpresent。Sotoo，then，istheearlierheatrelatedtothelater。Sothatthegreatnessandsmallness，also，ofthesensiblevolumeareextended，notbythematter"sacquiringanythingnew，butbecausethematterispotentiallymatterforbothstates；sothatthesamethingisdenseandrare，andthetwoqualitieshaveonematter。

Thedenseisheavy，andtherareislight。[Again，asthearcofacirclewhencontractedintoasmallerspacedoesnotacquireanewpartwhichisconvex，butwhatwastherehasbeencontracted；andasanypartoffirethatonetakeswillbehot；so，too，itisallaquestionofcontractionandexpansionofthesamematter。]Therearetwotypesineachcase，bothinthedenseandintherare；forboththeheavyandthehardarethoughttobedense，andcontrariwiseboththelightandthesoftarerare；andweightandhardnessfailtocoincideinthecaseofleadandiron。

Fromwhathasbeensaiditisevident，then，thatvoiddoesnotexisteitherseparate(eitherabsolutelyseparateorasaseparateelementintherare)orpotentially，unlessoneiswillingtocalltheconditionofmovementvoid，whateveritmaybe。Atthatratethematteroftheheavyandthelight，quamatterofthem，wouldbethevoid；forthedenseandtherareareproductiveoflocomotioninvirtueofthiscontrariety，andinvirtueoftheirhardnessandsoftnessproductiveofpassivityandimpassivity，i。e。notoflocomotionbutratherofqualitativechange。

Somuch，then，forthediscussionofthevoid，andofthesenseinwhichitexistsandthesenseinwhichitdoesnotexist。

NextfordiscussionafterthesubjectsmentionedisTime。Thebestplanwillbetobeginbyworkingoutthedifficultiesconnectedwithit，makinguseofthecurrentarguments。First，doesitbelongtotheclassofthingsthatexistortothatofthingsthatdonotexist?

Thensecondly，whatisitsnature?Tostart，then:thefollowingconsiderationswouldmakeonesuspectthatiteitherdoesnotexistatallorbarely，andinanobscureway。Onepartofithasbeenandisnot，whiletheotherisgoingtobeandisnotyet。Yettime-bothinfinitetimeandanytimeyouliketotake-ismadeupofthese。Onewouldnaturallysupposethatwhatismadeupofthingswhichdonotexistcouldhavenoshareinreality。

Further，ifadivisiblethingistoexist，itisnecessarythat，whenitexists，allorsomeofitspartsmustexist。Butoftimesomepartshavebeen，whileothershavetobe，andnopartofitisthoughitisdivisible。Forwhatis"now"isnotapart:apartisameasureofthewhole，whichmustbemadeupofparts。Time，ontheotherhand，isnotheldtobemadeupof"nows"。

Again，the"now"whichseemstoboundthepastandthefuture-doesitalwaysremainoneandthesameorisitalwaysotherandother?

Itishardtosay。

(1)Ifitisalwaysdifferentanddifferent，andifnoneofthepartsintimewhichareotherandotheraresimultaneous(unlesstheonecontainsandtheotheriscontained，astheshortertimeisbythelonger)，andifthe"now"whichisnot，butformerlywas，musthaveceased-to-beatsometime，the"nows"toocannotbesimultaneouswithoneanother，buttheprior"now"mustalwayshaveceased-to-be。

Buttheprior"now"cannothaveceased-to-beinitself(sinceitthenexisted)；yetitcannothaveceased-to-beinanother"now"。Forwemaylayitdownthatone"now"cannotbenexttoanother，anymorethanpointtopoint。Ifthenitdidnotcease-to-beinthenext"now"butinanother，itwouldexistsimultaneouslywiththeinnumerable"nows"betweenthetwo-whichisimpossible。

Yes，but(2)neitherisitpossibleforthe"now"toremainalwaysthesame。Nodeterminatedivisiblethinghasasingletermination，whetheritiscontinuouslyextendedinoneorinmorethanonedimension:butthe"now"isatermination，anditispossibletocutoffadeterminatetime。Further，ifcoincidenceintime(i。e。beingneitherpriornorposterior)meanstobe"inoneandthesame“now“"，then，ifbothwhatisbeforeandwhatisafterareinthissame"now"，thingswhichhappenedtenthousandyearsagowouldbesimultaneouswithwhathashappenedto-day，andnothingwouldbebeforeorafteranythingelse。

Thismayserveasastatementofthedifficultiesabouttheattributesoftime。

Astowhattimeisorwhatisitsnature，thetraditionalaccountsgiveusaslittlelightasthepreliminaryproblemswhichwehaveworkedthrough。

Someassertthatitis(1)themovementofthewhole，othersthatitis(2)thesphereitself。

(1)Yetpart，too，oftherevolutionisatime，butitcertainlyisnotarevolution:forwhatistakenispartofarevolution，notarevolution。Besides，ifthereweremoreheavensthanone，themovementofanyofthemequallywouldbetime，sothattherewouldbemanytimesatthesametime。

(2)Thosewhosaidthattimeisthesphereofthewholethoughtso，nodoubt，onthegroundthatallthingsareintimeandallthingsareinthesphereofthewhole。Theviewistoonaiveforittobeworthwhiletoconsidertheimpossibilitiesimpliedinit。

Butastimeismostusuallysupposedtobe(3)motionandakindofchange，wemustconsiderthisview。

Now(a)thechangeormovementofeachthingisonlyinthethingwhichchangesorwherethethingitselfwhichmovesorchangesmaychancetobe。Buttimeispresentequallyeverywhereandwithallthings。

Again，(b)changeisalwaysfasterorslower，whereastimeisnot:

for"fast"and"slow"aredefinedbytime-"fast"iswhatmovesmuchinashorttime，"slow"whatmoveslittleinalongtime；buttimeisnotdefinedbytime，bybeingeitheracertainamountoracertainkindofit。

Clearlythenitisnotmovement。(Weneednotdistinguishatpresentbetween"movement"and"change"。)

Butneitherdoestimeexistwithoutchange；forwhenthestateofourownmindsdoesnotchangeatall，orwehavenotnoticeditschanging，wedonotrealizethattimehaselapsed，anymorethanthosewhoarefabledtosleepamongtheheroesinSardiniadowhentheyareawakened；fortheyconnecttheearlier"now"withthelaterandmakethemone，cuttingouttheintervalbecauseoftheirfailuretonoticeit。So，justas，ifthe"now"werenotdifferentbutoneandthesame，therewouldnothavebeentime，sotoowhenitsdifferenceescapesournoticetheintervaldoesnotseemtobetime。If，then，thenon-realizationoftheexistenceoftimehappenstouswhenwedonotdistinguishanychange，butthesoulseemstostayinoneindivisiblestate，andwhenweperceiveanddistinguishwesaytimehaselapsed，evidentlytimeisnotindependentofmovementandchange。

Itisevident，then，thattimeisneithermovementnorindependentofmovement。

Wemusttakethisasourstarting-pointandtrytodiscover-sincewewishtoknowwhattimeis-whatexactlyithastodowithmovement。

Nowweperceivemovementandtimetogether:forevenwhenitisdarkandwearenotbeingaffectedthroughthebody，ifanymovementtakesplaceinthemindweatoncesupposethatsometimealsohaselapsed；andnotonlythatbutalso，whensometimeisthoughttohavepassed，somemovementalsoalongwithitseemstohavetakenplace。

Hencetimeiseithermovementorsomethingthatbelongstomovement。

Sincethenitisnotmovement，itmustbetheother。

Butwhatismovedismovedfromsomethingtosomething，andallmagnitudeiscontinuous。Thereforethemovementgoeswiththemagnitude。Becausethemagnitudeiscontinuous，themovementtoomustbecontinuous，andifthemovement，thenthetime；forthetimethathaspassedisalwaysthoughttobeinproportiontothemovement。

Thedistinctionof"before"and"after"holdsprimarily，then，inplace；andthereinvirtueofrelativeposition。Sincethen"before"

and"after"holdinmagnitude，theymustholdalsoinmovement，thesecorrespondingtothose。Butalsointimethedistinctionof"before"and"after"musthold，fortimeandmovementalwayscorrespondwitheachother。The"before"and"after"inmotionisidenticalinsubstratumwithmotionyetdiffersfromitindefinition，andisnotidenticalwithmotion。

Butweapprehendtimeonlywhenwehavemarkedmotion，markingitby"before"and"after"；anditisonlywhenwehaveperceived"before"

and"after"inmotionthatwesaythattimehaselapsed。NowwemarkthembyjudgingthatAandBaredifferent，andthatsomethirdthingisintermediatetothem。Whenwethinkoftheextremesasdifferentfromthemiddleandthemindpronouncesthatthe"nows"

aretwo，onebeforeandoneafter，itisthenthatwesaythatthereistime，andthisthatwesayistime。Forwhatisboundedbythe"now"isthoughttobetime-wemayassumethis。

When，therefore，weperceivethe"now"one，andneitherasbeforeandafterinamotionnorasanidentitybutinrelationtoa"before"

andan"after"，notimeisthoughttohaveelapsed，becausetherehasbeennomotioneither。Ontheotherhand，whenwedoperceivea"before"andan"after"，thenwesaythatthereistime。Fortimeisjustthis-numberofmotioninrespectof"before"and"after"。

Hencetimeisnotmovement，butonlymovementinsofarasitadmitsofenumeration。Aproofofthis:wediscriminatethemoreorthelessbynumber，butmoreorlessmovementbytime。Timethenisakindofnumber。(Number，wemustnote，isusedintwosenses-bothofwhatiscountedorthecountableandalsoofthatwithwhichwecount。Timeobviouslyiswhatiscounted，notthatwithwhichwecount:therearedifferentkindsofthing。)Justasmotionisaperpetualsuccession，soalsoistime。Buteverysimultaneoustimeisself-identical；forthe"now"asasubjectisanidentity，butitacceptsdifferentattributes。The"now"measurestime，insofarastimeinvolvesthe"beforeandafter"。

The"now"inonesenseisthesame，inanotheritisnotthesame。

Insofarasitisinsuccession，itisdifferent(whichisjustwhatitsbeingwassupposedtomean)，butitssubstratumisanidentity:formotion，aswassaid，goeswithmagnitude，andtime，aswemaintain，withmotion。Similarly，then，therecorrespondstothepointthebodywhichiscarriedalong，andbywhichweareawareofthemotionandofthe"beforeandafter"involvedinit。Thisisanidenticalsubstratum(whetherapointorastoneorsomethingelseofthekind)，butithasdifferentattributesasthesophistsassumethatCoriscus"beingintheLyceumisadifferentthingfromCoriscus"

beinginthemarket-place。Andthebodywhichiscarriedalongisdifferent，insofarasitisatonetimehereandatanotherthere。

Butthe"now"correspondstothebodythatiscarriedalong，astimecorrespondstothemotion。Foritisbymeansofthebodythatiscarriedalongthatwebecomeawareofthe"beforeandafter"themotion，andifweregardtheseascountablewegetthe"now"。Henceinthesealsothe"now"assubstratumremainsthesame(foritiswhatisbeforeandafterinmovement)，butwhatispredicatedofitisdifferent；foritisinsofarasthe"beforeandafter"isnumerablethatwegetthe"now"。Thisiswhatismostknowable:for，similarly，motionisknownbecauseofthatwhichismoved，locomotionbecauseofthatwhichiscarried。whatiscarriedisarealthing，themovementisnot。Thuswhatiscalled"now"inonesenseisalwaysthesame；inanotheritisnotthesame:forthisistruealsoofwhatiscarried。

Clearly，too，iftherewerenotime，therewouldbeno"now"，andviceversa。justasthemovingbodyanditslocomotioninvolveeachothermutually，sotoodothenumberofthemovingbodyandthenumberofitslocomotion。Forthenumberofthelocomotionistime，whilethe"now"correspondstothemovingbody，andisliketheunitofnumber。

Time，then，alsoisbothmadecontinuousbythe"now"anddividedatit。Forheretoothereisacorrespondencewiththelocomotionandthemovingbody。Forthemotionorlocomotionismadeonebythethingwhichismoved，becauseitisone-notbecauseitisoneinitsownnature(fortheremightbepausesinthemovementofsuchathing)-butbecauseitisoneindefinition:forthisdeterminesthemovementas"before"and"after"。Here，toothereisacorrespondencewiththepoint；forthepointalsobothconnectsandterminatesthelength-itisthebeginningofoneandtheendofanother。Butwhenyoutakeitinthisway，usingtheonepointastwo，apauseisnecessary，ifthesamepointistobethebeginningandtheend。The"now"ontheotherhand，sincethebodycarriedismoving，isalwaysdifferent。

Hencetimeisnotnumberinthesenseinwhichthereis"number"

ofthesamepointbecauseitisbeginningandend，butratherastheextremitiesofalineformanumber，andnotasthepartsofthelinedoso，bothforthereasongiven(forwecanusethemiddlepointastwo，sothatonthatanalogytimemightstandstill)，andfurtherbecauseobviouslythe"now"isnopartoftimenorthesectionanypartofthemovement，anymorethanthepointsarepartsoftheline-foritistwolinesthatarepartsofoneline。

Insofarthenasthe"now"isaboundary，itisnottime，butanattributeofit；insofarasitnumbers，itisnumber；forboundariesbelongonlytothatwhichtheybound，butnumber(e。g。ten)isthenumberofthesehorses，andbelongsalsoelsewhere。

Itisclear，then，thattimeis"numberofmovementinrespectofthebeforeandafter"，andiscontinuoussinceitisanattributeofwhatiscontinuous。

Thesmallestnumber，inthestrictsenseoftheword"number"，istwo。Butofnumberasconcrete，sometimesthereisaminimum，sometimesnot:e。g。ofa"line"，thesmallestinrespectofmultiplicityistwo(or，ifyoulike，one)，butinrespectofsizethereisnominimum；foreverylineisdividedadinfinitum。Henceitissowithtime。Inrespectofnumbertheminimumisone(ortwo)；inpointofextentthereisnominimum。

Itisclear，too，thattimeisnotdescribedasfastorslow，butasmanyorfewandaslongorshort。Forascontinuousitislongorshortandasanumbermanyorfew，butitisnotfastorslow-anymorethananynumberwithwhichwenumberisfastorslow。

Further，thereisthesametimeeverywhereatonce，butnotthesametimebeforeandafter，forwhilethepresentchangeisone，thechangewhichhashappenedandthatwhichwillhappenaredifferent。Timeisnotnumberwithwhichwecount，butthenumberofthingswhicharecounted，andthisaccordingasitoccursbeforeorafterisalwaysdifferent，forthe"nows"aredifferent。Andthenumberofahundredhorsesandahundredmenisthesame，butthethingsnumberedaredifferent-thehorsesfromthemen。Further，asamovementcanbeoneandthesameagainandagain，sotoocantime，e。g。ayearoraspringoranautumn。

Notonlydowemeasurethemovementbythetime，butalsothetimebythemovement，becausetheydefineeachother。Thetimemarksthemovement，sinceitisitsnumber，andthemovementthetime。Wedescribethetimeasmuchorlittle，measuringitbythemovement，justasweknowthenumberbywhatisnumbered，e。g。thenumberofthehorsesbyonehorseastheunit。Forweknowhowmanyhorsestherearebytheuseofthenumber；andagainbyusingtheonehorseasunitweknowthenumberofthehorsesitself。Soitiswiththetimeandthemovement；forwemeasurethemovementbythetimeandviceversa。Itisnaturalthatthisshouldhappen；forthemovementgoeswiththedistanceandthetimewiththemovement，becausetheyarequantaandcontinuousanddivisible。Themovementhastheseattributesbecausethedistanceisofthisnature，andthetimehasthembecauseofthemovement。Andwemeasureboththedistancebythemovementandthemovementbythedistance；forwesaythattheroadislong，ifthejourneyislong，andthatthisislong，iftheroadislong-thetime，too，ifthemovement，andthemovement，ifthetime。

Timeisameasureofmotionandofbeingmoved，anditmeasuresthemotionbydeterminingamotionwhichwillmeasureexactlythewholemotion，asthecubitdoesthelengthbydetermininganamountwhichwillmeasureoutthewhole。Further"tobeintime"meansformovement，thatbothitanditsessencearemeasuredbytime(forsimultaneouslyitmeasuresboththemovementanditsessence，andthisiswhatbeingintimemeansforit，thatitsessenceshouldbemeasured)。

Clearlythen"tobeintime"hasthesamemeaningforotherthingsalso，namely，thattheirbeingshouldbemeasuredbytime。"Tobeintime"isoneoftwothings:(1)toexistwhentimeexists，(2)aswesayofsomethingsthattheyare"innumber"。Thelattermeanseitherwhatisapartormodeofnumber-ingeneral，somethingwhichbelongstonumber-orthatthingshaveanumber。

Now，sincetimeisnumber，the"now"andthe"before"andthelikeareintime，justas"unit"and"odd"and"even"areinnumber，i。e。

inthesensethattheonesetbelongstonumber，theothertotime。

Butthingsareintimeastheyareinnumber。Ifthisisso，theyarecontainedbytimeasthingsinplacearecontainedbyplace。

Plainly，too，tobeintimedoesnotmeantoco-existwithtime，anymorethantobeinmotionorinplacemeanstoco-existwithmotionorplace。Forif"tobeinsomething"istomeanthis，thenallthingswillbeinanything，andtheheavenwillbeinagrain；forwhenthegrainis，thenalsoistheheaven。Butthisisamerelyincidentalconjunction，whereastheotherisnecessarilyinvolved:thatwhichisintimenecessarilyinvolvesthatthereistimewhenitis，andthatwhichisinmotionthatthereismotionwhenitis。

Sincewhatis"intime"issointhesamesenseaswhatisinnumberisso，atimegreaterthaneverythingintimecanbefound。Soitisnecessarythatallthethingsintimeshouldbecontainedbytime，justlikeotherthingsalsowhichare"inanything"，e。g。thethings"inplace"byplace。

Athing，then，willbeaffectedbytime，justasweareaccustomedtosaythattimewastesthingsaway，andthatallthingsgrowoldthroughtime，andthatthereisoblivionowingtothelapseoftime，butwedonotsaythesameofgettingtoknoworofbecomingyoungorfair。Fortimeisbyitsnaturethecauseratherofdecay，sinceitisthenumberofchange，andchangeremoveswhatis。

Hence，plainly，thingswhicharealwaysarenot，assuch，intime，fortheyarenotcontainedtime，noristheirbeingmeasuredbytime。Aproofofthisisthatnoneofthemisaffectedbytime，whichindicatesthattheyarenotintime。

Sincetimeisthemeasureofmotion，itwillbethemeasureofresttoo-indirectly。Forallrestisintime。Foritdoesnotfollowthatwhatisintimeismoved，thoughwhatisinmotionisnecessarilymoved。Fortimeisnotmotion，but"numberofmotion":andwhatisatrest，also，canbeinthenumberofmotion。Noteverythingthatisnotinmotioncanbesaidtobe"atrest"-butonlythatwhichcanbemoved，thoughitactuallyisnotmoved，aswassaidabove。

"Tobeinnumber"meansthatthereisanumberofthething，andthatitsbeingismeasuredbythenumberinwhichitis。Henceifathingis"intime"itwillbemeasuredbytime。Buttimewillmeasurewhatismovedandwhatisatrest，theonequamoved，theotherquaatrest；foritwillmeasuretheirmotionandrestrespectively。

Hencewhatismovedwillnotbemeasurablebythetimesimplyinsofarasithasquantity，butinsofarasitsmotionhasquantity。

Thusnoneofthethingswhichareneithermovednoratrestareintime:for"tobeintime"is"tobemeasuredbytime"，whiletimeisthemeasureofmotionandrest。

Plainly，then，neitherwilleverythingthatdoesnotexistbeintime，i。e。thosenon-existentthingsthatcannotexist，asthediagonalcannotbecommensuratewiththeside。

Generally，iftimeisdirectlythemeasureofmotionandindirectlyofotherthings，itisclearthatathingwhoseexistenceismeasuredbyitwillhaveitsexistenceinrestormotion。Thosethingsthereforewhicharesubjecttoperishingandbecoming-generally，thosewhichatonetimeexist，atanotherdonot-arenecessarilyintime:forthereisagreatertimewhichwillextendbothbeyondtheirexistenceandbeyondthetimewhichmeasurestheirexistence。Ofthingswhichdonotexistbutarecontainedbytimesomewere，e。g。Homeroncewas，somewillbe，e。g。afutureevent；thisdependsonthedirectioninwhichtimecontainsthem；ifonboth，theyhavebothmodesofexistence。Astosuchthingsasitdoesnotcontaininanyway，theyneitherwerenorarenorwillbe。Thesearethosenonexistentswhoseoppositesalwaysare，astheincommensurabilityofthediagonalalwaysis-andthiswillnotbeintime。Norwillthecommensurability，therefore；hencethiseternallyisnot，becauseitiscontrarytowhateternallyis。Athingwhosecontraryisnoteternalcanbeandnotbe，anditisofsuchthingsthatthereiscomingtobeandpassingaway。

The"now"isthelinkoftime，ashasbeensaid(foritconnectspastandfuturetime)，anditisalimitoftime(foritisthebeginningoftheoneandtheendoftheother)。Butthisisnotobviousasitiswiththepoint，whichisfixed。Itdividespotentially，andinsofarasitisdividingthe"now"isalwaysdifferent，butinsofarasitconnectsitisalwaysthesame，asitiswithmathematicallines。Fortheintellectitisnotalwaysoneandthesamepoint，sinceitisotherandotherwhenonedividestheline；

butinsofarasitisone，itisthesameineveryrespect。

Sothe"now"alsoisinonewayapotentialdividingoftime，inanothertheterminationofbothparts，andtheirunity。Andthedividingandtheunitingarethesamethingandinthesamereference，butinessencetheyarenotthesame。

Soonekindof"now"isdescribedinthisway:anotheriswhenthetimeisnearthiskindof"now"。"Hewillcomenow"becausehewillcometo-day；"hehascomenow"becausehecameto-day。ButthethingsintheIliadhavenothappened"now"，noristheflood"now"-notthatthetimefromnowtothemisnotcontinuous，butbecausetheyarenotnear。

"Atsometime"meansatimedeterminedinrelationtothefirstofthetwotypesof"now"，e。g。"atsometime"Troywastaken，and"atsometime"therewillbeaflood；foritmustbedeterminedwithreferencetothe"now"。Therewillthusbeadeterminatetimefromthis"now"tothat，andtherewassuchinreferencetothepastevent。

Butiftherebenotimewhichisnot"sometime"，everytimewillbedetermined。

Willtimethenfail?Surelynot，ifmotionalwaysexists。Istimethenalwaysdifferentordoesthesametimerecur?Clearlytimeis，inthesamewayasmotionis。Forifoneandthesamemotionsometimesrecurs，itwillbeoneandthesametime，andifnot，not。

Sincethe"now"isanendandabeginningoftime，notofthesametimehowever，buttheendofthatwhichispastandthebeginningofthatwhichistocome，itfollowsthat，asthecirclehasitsconvexityanditsconcavity，inasense，inthesamething，sotimeisalwaysatabeginningandatanend。Andforthisreasonitseemstobealwaysdifferent；forthe"now"isnotthebeginningandtheendofthesamething；ifitwere，itwouldbeatthesametimeandinthesamerespecttwoopposites。Andtimewillnotfail；foritisalwaysatabeginning。

"Presently"or"just"referstothepartoffuturetimewhichisneartheindivisiblepresent"now"("Whendoyouwalk?"Presently"，becausethetimeinwhichheisgoingtodosoisnear)，andtothepartofpasttimewhichisnotfarfromthe"now"("Whendoyouwalk?"

"Ihavejustbeenwalking")。ButtosaythatTroyhasjustbeentaken-wedonotsaythat，becauseitistoofarfromthe"now"。

"Lately"，too，referstothepartofpasttimewhichisnearthepresent"now"。"Whendidyougo?""Lately"，ifthetimeisneartheexistingnow。"Longago"referstothedistantpast。

"Suddenly"referstowhathasdepartedfromitsformerconditioninatimeimperceptiblebecauseofitssmallness；butitisthenatureofallchangetoalterthingsfromtheirformercondition。Intimeallthingscomeintobeingandpassaway；forwhichreasonsomecalleditthewisestofallthings，butthePythagoreanParoncalleditthemoststupid，becauseinitwealsoforget；andhiswasthetruerview。

Itisclearthenthatitmustbeinitself，aswesaidbefore，theconditionofdestructionratherthanofcomingintobeing(forchange，initself，makesthingsdepartfromtheirformercondition)，andonlyincidentallyofcomingintobeing，andofbeing。Asufficientevidenceofthisisthatnothingcomesintobeingwithoutitselfmovingsomehowandacting，butathingcanbedestroyedevenifitdoesnotmoveatall。Andthisiswhat，asarule，wechieflymeanbyathing"sbeingdestroyedbytime。Still，timedoesnotworkeventhischange；eventhissortofchangetakesplaceincidentallyintime。

Wehavestated，then，thattimeexistsandwhatitis，andinhowmanysenseswespeakofthe"now"，andwhat"atsometime"，"lately"，"presently"or"just"，"longago"，and"suddenly"mean。