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。