Butweshallsayinanswertothisargumentalsothatwhile
　　thereissomejustificationfortheirthinkingthatthechanging，when
　　itischanging，doesnotexist，yetitisafteralldisputable；for
　　thatwhichislosingaqualityhassomethingofthatwhichisbeing
　　lost，andofthatwhichiscomingtobe，somethingmustalreadybe。
　　Andingeneralifathingisperishing，willbepresentsomethingthat
　　exists；andifathingiscomingtobe，theremustbesomethingfrom
　　whichitcomestobeandsomethingbywhichitisgenerated，and
　　thisprocesscannotgoonadinfinitum-But，leavingthese
　　arguments，letusinsistonthis，thatitisnotthesamethingto
　　changeinquantityandinquality。Grantthatinquantityathingis
　　notconstant；stillitisinrespectofitsformthatweknoweach
　　thing-Andagain，itwouldbefairtocriticizethosewhoholdthis
　　viewforassertingaboutthewholematerialuniversewhattheysaw
　　onlyinaminorityevenofsensiblethings。Foronlythatregionof
　　thesensibleworldwhichimmediatelysurroundsusisalwaysinprocess
　　ofdestructionandgeneration；butthisis-sotospeak-notevena
　　fractionofthewhole，sothatitwouldhavebeenjustertoacquit
　　thispartoftheworldbecauseoftheotherpart，thantocondemn
　　theotherbecauseofthis-Andagain，obviouslyweshallmaketo
　　themalsothesamereplythatwemadelongago；wemustshowthem
　　andpersuadethemthatthereissomethingwhosenatureis
　　changeless。Indeed，thosewhosaythatthingsatthesametimeareand
　　arenot，shouldinconsequencesaythatallthingsareatrest
　　ratherthanthattheyareinmovement；forthereisnothingintowhich
　　theycanchange，sinceallattributesbelongalreadytoallsubjects。
　　Regardingthenatureoftruth，wemustmaintainthatnot
　　everythingwhichappearsistrue；firstly，becauseevenif
　　sensation-atleastoftheobjectpeculiartothesensein
　　question-isnotfalse，stillappearanceisnotthesameas
　　sensation-Again，itisfairtoexpresssurpriseatouropponents’
　　raisingthequestionwhethermagnitudesareasgreat，andcolours
　　areofsuchanature，astheyappeartopeopleatadistance，oras
　　theyappeartothosecloseathand，andwhethertheyaresuchas
　　theyappeartothehealthyortothesick，andwhetherthosethings
　　areheavywhichappearsototheweakorthosewhichappearsoto
　　thestrong，andthosethingstruewhichappeartothesleeingorto
　　thewaking。Forobviouslytheydonotthinkthesetobeopen
　　questions；noone，atleast，ifwhenheisinLibyahehasfanciedone
　　nightthatheisinAthens，startsfortheconcerthall-Andagain
　　withregardtothefuture，asPlatosays，surelytheopinionofthe
　　physicianandthatoftheignorantmanarenotequallyweighty，for
　　instance，onthequestionwhetheramanwillgetwellornot-And
　　again，amongsensationsthemselvesthesensationofaforeignobject
　　andthatoftheappropriateobject，orthatofakindredobjectand
　　thatoftheobjectofthesenseinquestion，arenotequally
　　authoritative，butinthecaseofcoloursight，nottaste，hasthe
　　authority，andinthecaseofflavourtaste，notsight；eachof
　　whichsensesneversaysatthesametimeofthesameobjectthatit
　　simultaneouslyis’soandnotso’-Butnotevenatdifferenttimes
　　doesonesensedisagreeaboutthequality，butonlyaboutthatto
　　whichthequalitybelongs。Imean，forinstance，thatthesamewine
　　mightseem，ifeitheritorone’sbodychanged，atonetimesweet
　　andatanothertimenotsweet；butatleastthesweet，suchasitis
　　whenitexists，hasneveryetchanged，butoneisalwaysrightabout
　　it，andthatwhichistobesweetisofnecessityofsuchandsucha
　　nature。Yetalltheseviewsdestroythisnecessity，leavingnothingto
　　beofnecessity，astheyleavenoessenceofanything；forthe
　　necessarycannotbeinthiswayandalsointhat，sothatif
　　anythingisofnecessity，itwillnotbe’bothsoandnotso’。
　　And，ingeneral，ifonlythesensibleexists，therewouldbe
　　nothingifanimatethingswerenot；fortherewouldbenofacultyof
　　sense。Nowtheviewthatneitherthesensiblequalitiesnorthe
　　sensationswouldexistisdoubtlesstruefortheyareaffectionsof
　　theperceiver，butthatthesubstratawhichcausethesensation
　　shouldnotexistevenapartfromsensationisimpossible。For
　　sensationissurelynotthesensationofitself，butthereis
　　somethingbeyondthesensation，whichmustbepriortothe
　　sensation；forthatwhichmovesispriorinnaturetothatwhichis
　　moved，andiftheyarecorrelativeterms，thisisnolessthecase。
　　Thereare，bothamongthosewhohavetheseconvictionsandamong
　　thosewhomerelyprofesstheseviews，somewhoraiseadifficultyby
　　asking，whoistobethejudgeofthehealthyman，andingeneral
　　whoislikelytojudgerightlyoneachclassofquestions。Butsuch
　　inquiriesarelikepuzzlingoverthequestionwhetherwearenow
　　asleeporawake。Andallsuchquestionshavethesamemeaning。These
　　peopledemandthatareasonshallbegivenforeverything；forthey
　　seekastarting-point，andtheyseektogetthisbydemonstration，whileitisobviousfromtheiractionsthattheyhavenoconviction。
　　Buttheirmistakeiswhatwehavestatedittobe；theyseeka
　　reasonforthingsforwhichnoreasoncanbegiven；forthe
　　starting-pointofdemonstrationisnotdemonstration。
　　These，then，mightbeeasilypersuadedofthistruth，foritis
　　notdifficulttograsp；butthosewhoseekmerelycompulsionin
　　argumentseekwhatisimpossible；fortheydemandtobeallowedto
　　contradictthemselves-aclaimwhichcontradictsitselffromthevery
　　first-Butifnotallthingsarerelative，butsomeareself-existent，
　　noteverythingthatappearswillbetrue；forthatwhichappearsis
　　apparenttosomeone；sothathewhosaysallthingsthatappearare
　　true，makesallthingsrelative。And，therefore，thosewhoaskfor
　　anirresistibleargument，andatthesametimedemandtobecalled
　　toaccountfortheirviews，mustguardthemselvesbysayingthatthe
　　truthisnotthatwhatappearsexists，butthatwhatappearsexists
　　forhimtowhomitappears，andwhen，andtothesensetowhich，and
　　undertheconditionsunderwhichitappears。Andiftheygivean
　　accountoftheirview，butdonotgiveitinthisway，theywill
　　soonfindthemselvescontradictingthemselves。Foritispossiblethat
　　thesamethingmayappeartobehoneytothesight，butnottothe
　　taste，andthat，sincewehavetwoeyes，thingsmaynotappearthe
　　sametoeach，iftheirsightisunlike。Fortothosewhoforthe
　　reasonsnamedsometimeagosaythatwhatappearsistrue，and
　　thereforethatallthingsarealikefalseandtrue，forthingsdo
　　notappeareitherthesametoallmenoralwaysthesametothesame
　　man，butoftenhavecontraryappearancesatthesametimefortouch
　　saystherearetwoobjectswhenwecrossourfingers，whilesightsays
　　thereisone-totheseweshallsay’yes，butnottothesamesense
　　andinthesamepartofitandunderthesameconditionsandatthe
　　sametime’，sothatwhatappearswillbewiththesequalifications
　　true。Butperhapsforthisreasonthosewhoarguethusnotbecause
　　theyfeeladifficultybutforthesakeofargument，shouldsaythat
　　thisisnottrue，buttrueforthisman。Andashasbeensaid
　　before，theymustmakeeverythingrelative-relativetoopinionand
　　perception，sothatnothingeitherhascometobeorwillbewithout
　　someone’sfirstthinkingso。Butifthingshavecometobeorwill
　　be，evidentlynotallthingswillberelativetoopinion-Again，if
　　athingisone，itisinrelationtoonethingortoadefinitenumber
　　ofthings；andifthesamethingisbothhalfandequal，itisnot
　　tothedoublethattheequaliscorrelative。If，then，inrelation
　　tothatwhichthinks，manandthatwhichisthoughtarethesame，
　　manwillnotbethatwhichthinks，butonlythatwhichisthought。And
　　ifeachthingistoberelativetothatwhichthinks，thatwhich
　　thinkswillberelativetoaninfinityofspecificallydifferent
　　things。
　　Letthis，then，sufficetoshow1thatthemostindisputable
　　ofallbeliefsisthatcontradictorystatementsarenotatthesame
　　timetrue，and2whatconsequencesfollowfromtheassertionthat
　　theyare，and3whypeopledoassertthis。Nowsinceitis
　　impossiblethatcontradictoriesshouldbeatthesametimetrueofthe
　　samething，obviouslycontrariesalsocannotbelongatthesametime
　　tothesamething。Forofcontraries，oneisaprivationnoless
　　thanitisacontrary-andaprivationoftheessentialnature；and
　　privationisthedenialofapredicatetoadeterminategenus。If，
　　then，itisimpossibletoaffirmanddenytrulyatthesametime，it
　　isalsoimpossiblethatcontrariesshouldbelongtoasubjectatthe
　　sametime，unlessbothbelongtoitinparticularrelations，oronein
　　aparticularrelationandonewithoutqualification。
　　Butontheotherhandtherecannotbeanintermediatebetween
　　contradictories，butofonesubjectwemusteitheraffirmordeny
　　anyonepredicate。Thisisclear，inthefirstplace，ifwedefine
　　whatthetrueandthefalseare。Tosayofwhatisthatitisnot，
　　orofwhatisnotthatitis，isfalse，whiletosayofwhatisthat
　　itis，andofwhatisnotthatitisnot，istrue；sothathewhosays
　　ofanythingthatitis，orthatitisnot，willsayeitherwhatis
　　trueorwhatisfalse；butneitherwhatisnorwhatisnotissaid
　　tobeornottobe-Again，theintermediatebetweenthe
　　contradictorieswillbesoeitherinthewayinwhichgreyis
　　betweenblackandwhite，orasthatwhichisneithermannorhorse
　　isbetweenmanandhorse。aIfitwereofthelatterkind，it
　　couldnotchangeintotheextremesforchangeisfromnot-goodto
　　good，orfromgoodtonot-good，butasamatteroffactwhenthereis
　　anintermediateitisalwaysobservedtochangeintotheextremes。For
　　thereisnochangeexcepttooppositesandtotheirintermediates。b
　　Butifitisreallyintermediate，inthiswaytootherewouldhave
　　tobeachangetowhite，whichwasnotfromnot-white；butasitis，
　　thisisneverseen-Again，everyobjectofunderstandingorreasonthe
　　understandingeitheraffirmsordenies-thisisobviousfromthe
　　definition-wheneveritsayswhatistrueorfalse。Whenitconnectsin
　　onewaybyassertionornegation，itsayswhatistrue，andwhenit
　　doessoinanotherway，whatisfalse-Again，theremustbean
　　intermediatebetweenallcontradictories，ifoneisnotarguingmerely
　　forthesakeofargument；sothatitwillbepossibleforamantosay
　　whatisneithertruenoruntrue，andtherewillbeamiddlebetween
　　thatwhichisandthatwhichisnot，sothattherewillalsobeakind
　　ofchangeintermediatebetweengenerationanddestruction-Again，in
　　allclassesinwhichthenegationofanattributeinvolvesthe
　　assertionofitscontrary，eveninthesetherewillbean
　　intermediate；forinstance，inthesphereofnumberstherewillbe
　　numberwhichisneitheroddnornot-odd。Butthisisimpossible，asis
　　obviousfromthedefinition-Again，theprocesswillgoonad
　　infinitum，andthenumberofrealitieswillbenotonlyhalfas
　　greatagain，butevengreater。Foragainitwillbepossibletodeny
　　thisintermediatewithreferencebothtoitsassertionandtoits
　　negation，andthisnewtermwillbesomedefinitething；forits
　　essenceissomethingdifferent-Again，whenaman，onbeingasked
　　whetherathingiswhite，says’no’，hehasdeniednothingexceptthat
　　itis；anditsnotbeingisanegation。
　　Somepeoplehaveacquiredthisopinionasotherparadoxical
　　opinionshavebeenacquired；whenmencannotrefuteeristical
　　arguments，theygiveintotheargumentandagreethatthe
　　conclusionistrue。This，then，iswhysomeexpressthisview；
　　othersdosobecausetheydemandareasonforeverything。Andthe
　　starting-pointindealingwithallsuchpeopleisdefinition。Now
　　thedefinitionrestsonthenecessityoftheirmeaningsomething；
　　fortheformofwordsofwhichthewordisasignwillbeits
　　definition-WhilethedoctrineofHeraclitus，thatallthingsare
　　andarenot，seemstomakeeverythingtrue，thatofAnaxagoras，that
　　thereisanintermediatebetweenthetermsofacontradiction，seems
　　tomakeeverythingfalse；forwhenthingsaremixed，themixtureis
　　neithergoodnornot-good，sothatonecannotsayanythingthatis
　　true。