2
WemaydistinguishgenerallybetweenpredicatingBofAbecauseitAisitself，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。
Iftheplaceisinthethingitmustbeifitiseithershapeormatterplacewillhaveaplace:forboththeformandtheindeterminateundergochangeandmotionalongwiththething，andarenotalwaysinthesameplace，butarewherethethingis。Hencetheplacewillhaveaplace。
Further，whenwaterisproducedfromair，theplacehasbeendestroyed，fortheresultingbodyisnotinthesameplace。Whatsortofdestructionthenisthat?
Thisconcludesmystatementofthereasonswhyspacemustbesomething，andagainofthedifficultiesthatmayberaisedaboutitsessentialnature。
3
Thenextstepwemusttakeistoseeinhowmanysensesonethingissaidtobe'in'another。
1Asthefingeris'in'thehandandgenerallythepart'in'thewhole。
2Asthewholeis'in'theparts:forthereisnowholeoverandabovetheparts。
3Asmanis'in'animalandgenerallyspecies'in'genus。
4Asthegenusis'in'thespeciesandgenerallythepartofthespecificform'in'thedefinitionofthespecificform。
5Ashealthis'in'thehotandthecoldandgenerallytheform'in'thematter。
6AstheaffairsofGreececentre'in'theking，andgenerallyeventscentre'in'theirprimarymotiveagent。
7Astheexistenceofathingcentres'initsgoodandgenerally'in'itsend，i。e。in'thatforthesakeofwhich'itexists。
8Inthestrictestsenseofall，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'isinbodyforthevisiblesurfaceisinbody，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，namelyifwinewine，willbeinit。
Obviouslythenathingcannotbeinitselfprimarily。
Zeno'sproblem-thatifPlaceissomethingitmustbeinsomething-isnotdifficulttosolve。Thereisnothingtopreventthefirstplacefrombeing'in'somethingelse-notindeedinthatas'in'place，butashealthis'in'thehotasapositivedeterminationofitorasthehotis'in'bodyasanaffection。Soweescapetheinfiniteregress。
Anotherthingisplain:sincethevesselisnopartofwhatisinitwhatcontainsinthestrictsenseisdifferentfromwhatiscontained，placecouldnotbeeitherthematterortheformofthethingcontained，butmustdifferent-forthelatter，boththematterandtheshape，arepartsofwhatiscontained。
Thisthenmayserveasacriticalstatementofthedifficultiesinvolved。
4
Whatthenafterallisplace?Theanswertothisquestionmaybeelucidatedasfollows。
Letustakeforgrantedaboutitthevariouscharacteristicswhicharesupposedcorrectlytobelongtoitessentially。Weassumethen-
1Placeiswhatcontainsthatofwhichitistheplace。
2Placeisnopartofthething。
3Theimmediateplaceofathingisneitherlessnorgreaterthanthething。
4Placecanbeleftbehindbythethingandisseparable。Inaddition:
5Allplaceadmitsofthedistinctionofupanddown，andeachofthebodiesisnaturallycarriedtoitsappropriateplaceandreststhere，andthismakestheplaceeitherupordown。
Havinglaidthesefoundations，wemustcompletethetheory。Weoughttotrytomakeourinvestigationsuchaswillrenderanaccountofplace，andwillnotonlysolvethedifficultiesconnectedwithit，butwillalsoshowthattheattributessupposedtobelongtoitdoreallybelongtoit，andfurtherwillmakeclearthecauseofthetroubleandofthedifficultiesaboutit。Suchisthemostsatisfactorykindofexposition。
Firstthenwemustunderstandthatplacewouldnothavebeenthoughtof，iftherehadnotbeenaspecialkindofmotion，namelythatwithrespecttoplace。Itischieflyforthisreasonthatwesupposetheheavenalsotobeinplace，becauseitisinconstantmovement。Ofthiskindofchangetherearetwospecies-locomotionontheonehandand，ontheother，increaseanddiminution。Forthesetooinvolvevariationofplace:whatwastheninthisplacehasnowinturnchangedtowhatislargerorsmaller。
Again，whenwesayathingis'moved'，thepredicateeither1
belongstoitactually，invirtueofitsownnature，or2invirtueofsomethingconjoinedwithit。Inthelattercaseitmaybeeitherasomethingwhichbyitsownnatureiscapableofbeingmoved，e。g。thepartsofthebodyorthenailintheship，orb
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:
1Theshapeissupposedtobeplacebecauseitsurrounds，fortheextremitiesofwhatcontainsandofwhatiscontainedarecoincident。Boththeshapeandtheplace，itistrue，areboundaries。Butnotofthesamething:theformistheboundaryofthething，theplaceistheboundaryofthebodywhichcontainsit。
2Theextensionbetweentheextremitiesisthoughttobesomething，becausewhatiscontainedandseparatemayoftenbechangedwhilethecontainerremainsthesameaswatermaybepouredfromavessel-theassumptionbeingthattheextensionissomethingoverandabovethebodydisplaced。Butthereisnosuchextension。Oneofthebodieswhichchangeplacesandarenaturallycapableofbeingincontactwiththecontainerfallsinwhicheveritmaychancetobe。
Iftherewereanextensionwhichweresuchastoexistindependentlyandbepermanent，therewouldbeaninfinityofplacesinthesamething。Forwhenthewaterandtheairchangeplaces，alltheportionsofthetwotogetherwillplaythesamepartinthewholewhichwaspreviouslyplayedbyallthewaterinthevessel；atthesametimetheplacetoowillbeundergoingchange；sothattherewillbeanotherplacewhichistheplaceoftheplace，andmanyplaceswillbecoincident。Thereisnotadifferentplaceofthepart，inwhichitismoved，whenthewholevesselchangesitsplace:itisalwaysthesame:foritisintheproximateplacewheretheyarethattheairandthewaterorthepartsofthewatersucceedeachother，notinthatplaceinwhichtheycometobe，whichispartoftheplacewhichistheplaceofthewholeworld。
3Thematter，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。
5
Ifthenabodyhasanotherbodyoutsideitandcontainingit，itisinplace，andifnot，not。Thatiswhy，evenifthereweretobewaterwhichhadnotacontainer，thepartsofit，ontheonehand，willbemovedforonepartiscontainedinanother，while，ontheotherhand，thewholewillbemovedinonesense，butnotinanother。Forasawholeitdoesnotsimultaneouslychangeitsplace，thoughitwillbemovedinacircle:forthisplaceistheplaceofitsparts。Somethingsaremoved，notupanddown，butinacircle；
othersupanddown，suchthingsnamelyasadmitofcondensationandrarefaction。
Aswasexplained，somethingsarepotentiallyinplace，othersactually。So，whenyouhaveahomogeneoussubstancewhichiscontinuous，thepartsarepotentiallyinplace:whenthepartsareseparated，butincontact，likeaheap，theyareactuallyinplace。
Again，1somethingsareperseinplace，namelyeverybodywhichismovableeitherbywayoflocomotionorbywayofincreaseispersesomewhere，buttheheaven，ashasbeensaid，isnotanywhereasawhole，norinanyplace，ifatleast，aswemustsuppose，nobodycontainsit。Onthelineonwhichitismoved，itspartshaveplace:
foreachiscontiguousthenext。
But2otherthingsareinplaceindirectly，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:
1Thereisnonecessitythattheplaceshouldgrowwiththebodyinit，2Northatapointshouldhaveaplace，3Northattwobodiesshouldbeinthesameplace，4Northatplaceshouldbeacorporealinterval:forwhatisbetweentheboundariesoftheplaceisanybodywhichmaychancetobethere，notanintervalinbody。
Further，5placeisalsosomewhere，notinthesenseofbeinginaplace，butasthelimitisinthelimited；fornoteverythingthatisisinplace，butonlymovablebody。
Also6itisreasonablethateachkindofbodyshouldbecarriedtoitsownplace。Forabodywhichisnextintheseriesandincontactnotbycompulsionisakin，andbodieswhichareuniteddonotaffecteachother，whilethosewhichareincontactinteractoneachother。
Nor7isitwithoutreasonthateachshouldremainnaturallyinitsproperplace。Forthisparthasthesamerelationtoitsplace，asaseparableparttoitswhole，aswhenonemovesapartofwaterorair:so，too，airisrelatedtowater，fortheoneislikematter，theotherform-wateristhematterofair，airasitweretheactualityofwater，forwaterispotentiallyair，whileairispotentiallywater，thoughinanotherway。
Thesedistinctionswillbedrawnmorecarefullylater。Onthepresentoccasionitwasnecessarytorefertothem:whathasnowbeenstatedobscurelywillthenbemademoreclear。Ifthematterandthefulfilmentarethesamethingforwaterisboth，theonepotentially，theothercompletely，waterwillberelatedtoairinawayasparttowhole。Thatiswhythesehavecontact:itisorganicunionwhenbothbecomeactuallyone。
Thisconcludesmyaccountofplace-bothofitsexistenceandofitsnature。
6
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。Theyholdthateverythingwhichisinbodyisbodyandsaythatwhathasnothinginitatallisvoidsowhatisfullofairisvoid。Itisnotthentheexistenceofairthatneedstobeproved，butthenon-existenceofaninterval，differentfromthebodies，eitherseparableoractual-anintervalwhichdividesthewholebodysoastobreakitscontinuity，asDemocritusandLeucippushold，andmanyotherphysicists-orevenperhapsassomethingwhichisoutsidethewholebody，whichremainscontinuous。
Thesepeople，then，havenotreachedeventhethresholdoftheproblem，butratherthosewhosaythatthevoidexists。
1Theyargue，foronething，thatchangeinplacei。e。locomotionandincreasewouldnotbe。Foritismaintainedthatmotionwouldseemnottoexist，iftherewerenovoid，sincewhatisfullcannotcontainanythingmore。Ifitcould，andthereweretwobodiesinthesameplace，itwouldalsobetruethatanynumberofbodiescouldbetogether；foritisimpossibletodrawalineofdivisionbeyondwhichthestatementwouldbecomeuntrue。Ifthiswerepossible，itwouldfollowalsothatthesmallestbodywouldcontainthegreatest；for'manyalittlemakesamickle':thusifmanyequalbodiescanbetogether，soalsocanmanyunequalbodies。
Melissus，indeed，infersfromtheseconsiderationsthattheAllisimmovable；forifitweremovedtheremust，hesays，bevoid，butvoidisnotamongthethingsthatexist。
Thisargument，then，isonewayinwhichtheyshowthatthereisavoid。
2Theyreasonfromthefactthatsomethingsareobservedtocontractandbecompressed，aspeoplesaythatacaskwillholdthewinewhichformerlyfilledit，alongwiththeskinsintowhichthewinehasbeendecanted，whichimpliesthatthecompressedbodycontractsintothevoidspresentinit。
Again3increase，too，isthoughttotakealwaysbymeansofvoid，fornutrimentisbody，anditisimpossiblefortwobodiestobetogether。Aproofofthistheyfindalsoinwhathappenstoashes，whichabsorbasmuchwaterastheemptyvessel。
ThePythagoreans，too，4heldthatvoidexistsandthatitenterstheheavenitself，whichasitwereinhalesit，fromtheinfiniteair。Furtheritisthevoidwhichdistinguishesthenaturesofthings，asifitwerelikewhatseparatesanddistinguishesthetermsofaseries。Thisholdsprimarilyinthenumbers，forthevoiddistinguishestheirnature。
These，then，andsomany，arethemaingroundsonwhichpeoplehavearguedforandagainsttheexistenceofthevoid。
7
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。Sosomesaythatthevoidisthematterofthebodytheyidentifytheplace，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。
Andthingscanalsobecompressednotintoavoidbutbecausetheysqueezeoutwhatiscontainedinthemas，forinstance，whenwateriscompressedtheairwithinitissqueezedout；andthingscanincreaseinsizenotonlybytheentranceofsomethingbutalsobyqualitativechange；e。g。ifwaterweretobetransformedintoair。
Ingeneral，boththeargumentaboutincreaseofsizeandthataboutwaterpouredontotheashesgetintheirownway。Foreithernotanyandeverypartofthebodyisincreased，orbodiesmaybeincreasedotherwisethanbytheadditionofbody，ortheremaybetwobodiesinthesameplaceinwhichcasetheyareclaimingtosolveaquitegeneraldifficulty，butarenotprovingtheexistenceofvoid，orthewholebodymustbevoid，ifitisincreasedineverypartandisincreasedbymeansofvoid。Thesameargumentappliestotheashes。
Itisevident，then，thatitiseasytorefutetheargumentsbywhichtheyprovetheexistenceofthevoid。
8
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，andifthereiscompulsorymovementtheremustalsobenaturalforcompulsorymovementiscontrarytonature，andmovementcontrarytonatureisposteriortothataccordingtonature，sothatifeachofthenaturalbodieshasnotanaturalmovement，noneoftheothermovementscanexist；buthowcantherebenaturalmovementifthereisnodifferencethroughoutthevoidortheinfinite?Forinsofarasitisinfinite，therewillbenoupordownormiddle，andinsofarasitisavoid，updiffersnowhitfromdown；forasthereisnodifferenceinwhatisnothing，thereisnoneinthevoidforthevoidseemstobeanon-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，intimeEifthelengthofBisegualtoD，inproportiontothedensityofthehinderingbody。ForletBbewaterandDair；
thenbysomuchasairisthinnerandmoreincorporealthanwater，A
willmovethroughDfasterthanthroughB。Letthespeedhavethesameratiotothespeed，then，thatairhastowater。Thenifairistwiceasthin，thebodywilltraverseBintwicethetimethatitdoesD，andthetimeGwillbetwicethetimeE。Andalways，bysomuchasthemediumismoreincorporealandlessresistantandmoreeasilydivided，thefasterwillbethemovement。
Nowthereisnoratioinwhichthevoidisexceededbybody，asthereisnoratioof0toanumber。Forif4exceeds3by1，and2
bymorethan1，and1bystillmorethanitexceeds2，stillthereisnoratiobywhichitexceeds0；forthatwhichexceedsmustbedivisibleintotheexcessthatwhichisexceeded，sothatwillbewhatitexceeds0by0。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。thatbetweenanytwomovementsthereisaratiofortheyoccupytime，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。
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Therearesomewhothinkthattheexistenceofrarityanddensityshowsthatthereisavoid。Ifrarityanddensitydonotexist，theysay，neithercanthingscontractandbecompressed。Butifthiswerenottotakeplace，eithertherewouldbenomovementatall，ortheuniversewouldbulge，asXuthussaid，orairandwatermustalwayschangeintoequalamountse。g。ifairhasbeenmadeoutofacupfulofwater，atthesametimeoutofanequalamountofairacupfulofwatermusthavebeenmade，orvoidmustnecessarilyexist；forcompressionandexpansioncannottakeplaceotherwise。
Now，iftheymeanbytherarethatwhichhasmanyvoidsexistingseparately，itisplainthatifvoidcannotexistseparateanymorethanaplacecanexistwithanextensionalltoitself，neithercantherareexistinthissense。Butiftheymeanthatthereisvoid，notseparatelyexistent，butstillpresentintherare，thisislessimpossible，yet，first，thevoidturnsoutnottobeaconditionofallmovement，butonlyofmovementupwardsfortherareislight，whichisthereasonwhytheysayfireisrare；second，thevoidturnsouttobeaconditionofmovementnotasthatinwhichittakesplace，butinthatthevoidcarriesthingsupasskinsbybeingcarriedupthemselvescarryupwhatiscontinuouswiththem。Yethowcanvoidhavealocalmovementoraplace?Forthusthatintowhichvoidmovesistillthenvoidofavoid。
Again，howwilltheyexplain，inthecaseofwhatisheavy，itsmovementdownwards?Anditisplainthatiftherarerandmorevoidathingisthequickeritwillmoveupwards，ifitwerecompletelyvoiditwouldmovewithamaximumspeed！Butperhapseventhisisimpossible，thatitshouldmoveatall；thesamereasonwhichshowedthatinthevoidallthingsareincapableofmovingshowsthatthevoidcannotmove，viz。thefactthatthespeedsareincomparable。
Sincewedenythatavoidexists，butfortheresttheproblemhasbeentrulystated，thateithertherewillbenomovement，ifthereisnottobecondensationandrarefaction，ortheuniversewillbulge，oratransformationofwaterintoairwillalwaysbebalancedbyanequaltransformationofairintowaterforitisclearthattheairproducedfromwaterisbulkierthanthewater: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，convexityhasnotcometoexistinanythingthatwasnotconvexbutstraightfordifferencesofdegreedonotdependonanintermissionofthequality；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，thatvoiddoesnotexisteitherseparateeitherabsolutelyseparateorasaseparateelementintherareorpotentially，unlessoneiswillingtocalltheconditionofmovementvoid，whateveritmaybe。Atthatratethematteroftheheavyandthelight，quamatterofthem，wouldbethevoid；forthedenseandtherareareproductiveoflocomotioninvirtueofthiscontrariety，andinvirtueoftheirhardnessandsoftnessproductiveofpassivityandimpassivity，i。e。notoflocomotionbutratherofqualitativechange。
Somuch，then，forthediscussionofthevoid，andofthesenseinwhichitexistsandthesenseinwhichitdoesnotexist。
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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。
1Ifitisalwaysdifferentanddifferent，andifnoneofthepartsintimewhichareotherandotheraresimultaneousunlesstheonecontainsandtheotheriscontained，astheshortertimeisbythelonger，andifthe'now'whichisnot，butformerlywas，musthaveceased-to-beatsometime，the'nows'toocannotbesimultaneouswithoneanother，buttheprior'now'mustalwayshaveceased-to-be。
Buttheprior'now'cannothaveceased-to-beinitselfsinceitthenexisted；yetitcannothaveceased-to-beinanother'now'。Forwemaylayitdownthatone'now'cannotbenexttoanother，anymorethanpointtopoint。Ifthenitdidnotcease-to-beinthenext'now'butinanother，itwouldexistsimultaneouslywiththeinnumerable'nows'betweenthetwo-whichisimpossible。
Yes，but2neitherisitpossibleforthe'now'toremainalwaysthesame。Nodeterminatedivisiblethinghasasingletermination，whetheritiscontinuouslyextendedinoneorinmorethanonedimension:butthe'now'isatermination，anditispossibletocutoffadeterminatetime。Further，ifcoincidenceintimei。e。beingneitherpriornorposteriormeanstobe'inoneandthesame“now“'，then，ifbothwhatisbeforeandwhatisafterareinthissame'now'，thingswhichhappenedtenthousandyearsagowouldbesimultaneouswithwhathashappenedto-day，andnothingwouldbebeforeorafteranythingelse。
Thismayserveasastatementofthedifficultiesabouttheattributesoftime。
Astowhattimeisorwhatisitsnature，thetraditionalaccountsgiveusaslittlelightasthepreliminaryproblemswhichwehaveworkedthrough。
Someassertthatitis1themovementofthewhole，othersthatitis2thesphereitself。
1Yetpart，too，oftherevolutionisatime，butitcertainlyisnotarevolution:forwhatistakenispartofarevolution，notarevolution。Besides，ifthereweremoreheavensthanone，themovementofanyofthemequallywouldbetime，sothattherewouldbemanytimesatthesametime。
2Thosewhosaidthattimeisthesphereofthewholethoughtso，nodoubt，onthegroundthatallthingsareintimeandallthingsareinthesphereofthewhole。Theviewistoonaiveforittobeworthwhiletoconsidertheimpossibilitiesimpliedinit。
Butastimeismostusuallysupposedtobe3motionandakindofchange，wemustconsiderthisview。
Nowathechangeormovementofeachthingisonlyinthethingwhichchangesorwherethethingitselfwhichmovesorchangesmaychancetobe。Buttimeispresentequallyeverywhereandwithallthings。
Again，bchangeisalwaysfasterorslower，whereastimeisnot:
for'fast'and'slow'aredefinedbytime-'fast'iswhatmovesmuchinashorttime，'slow'whatmoveslittleinalongtime；buttimeisnotdefinedbytime，bybeingeitheracertainamountoracertainkindofit。
Clearlythenitisnotmovement。Weneednotdistinguishatpresentbetween'movement'and'change'。
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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，itisdifferentwhichisjustwhatitsbeingwassupposedtomean，butitssubstratumisanidentity:formotion，aswassaid，goeswithmagnitude，andtime，aswemaintain，withmotion。Similarly，then，therecorrespondstothepointthebodywhichiscarriedalong，andbywhichweareawareofthemotionandofthe'beforeandafter'involvedinit。Thisisanidenticalsubstratumwhetherapointorastoneorsomethingelseofthekind，butithasdifferentattributesasthesophistsassumethatCoriscus'beingintheLyceumisadifferentthingfromCoriscus'
beinginthemarket-place。Andthebodywhichiscarriedalongisdifferent，insofarasitisatonetimehereandatanotherthere。
Butthe'now'correspondstothebodythatiscarriedalong，astimecorrespondstothemotion。Foritisbymeansofthebodythatiscarriedalongthatwebecomeawareofthe'beforeandafter'themotion，andifweregardtheseascountablewegetthe'now'。Henceinthesealsothe'now'assubstratumremainsthesameforitiswhatisbeforeandafterinmovement，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-notbecauseitisoneinitsownnaturefortheremightbepausesinthemovementofsuchathing-butbecauseitisoneindefinition:forthisdeterminesthemovementas'before'and'after'。Here，toothereisacorrespondencewiththepoint；forthepointalsobothconnectsandterminatesthelength-itisthebeginningofoneandtheendofanother。Butwhenyoutakeitinthisway，usingtheonepointastwo，apauseisnecessary，ifthesamepointistobethebeginningandtheend。The'now'ontheotherhand，sincethebodycarriedismoving，isalwaysdifferent。
Hencetimeisnotnumberinthesenseinwhichthereis'number'
ofthesamepointbecauseitisbeginningandend，butratherastheextremitiesofalineformanumber，andnotasthepartsofthelinedoso，bothforthereasongivenforwecanusethemiddlepointastwo，sothatonthatanalogytimemightstandstill，andfurtherbecauseobviouslythe'now'isnopartoftimenorthesectionanypartofthemovement，anymorethanthepointsarepartsoftheline-foritistwolinesthatarepartsofoneline。
Insofarthenasthe'now'isaboundary，itisnottime，butanattributeofit；insofarasitnumbers，itisnumber；forboundariesbelongonlytothatwhichtheybound，butnumbere。g。tenisthenumberofthesehorses，andbelongsalsoelsewhere。
Itisclear，then，thattimeis'numberofmovementinrespectofthebeforeandafter'，andiscontinuoussinceitisanattributeofwhatiscontinuous。
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Thesmallestnumber，inthestrictsenseoftheword'number'，istwo。Butofnumberasconcrete，sometimesthereisaminimum，sometimesnot:e。g。ofa'line'，thesmallestinrespectofmultiplicityistwoor，ifyoulike，one，butinrespectofsizethereisnominimum；foreverylineisdividedadinfinitum。Henceitissowithtime。Inrespectofnumbertheminimumisoneortwo；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，thatbothitanditsessencearemeasuredbytimeforsimultaneouslyitmeasuresboththemovementanditsessence，andthisiswhatbeingintimemeansforit，thatitsessenceshouldbemeasured。
Clearlythen'tobeintime'hasthesamemeaningforotherthingsalso，namely，thattheirbeingshouldbemeasuredbytime。'Tobeintime'isoneoftwothings:1toexistwhentimeexists，2aswesayofsomethingsthattheyare'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。
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The'now'isthelinkoftime，ashasbeensaidforitconnectspastandfuturetime，anditisalimitoftimeforitisthebeginningoftheoneandtheendoftheother。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，theconditionofdestructionratherthanofcomingintobeingforchange，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。