第6章

Butevidentlythereisafirstprinciple，andthecausesofthings

areneitheraninfiniteseriesnorinfinitelyvariousinkind。For

neithercanonethingproceedfromanother，asfrommatter，ad

infinitum(e。g。fleshfromearth，earthfromair，airfromfire，and

soonwithoutstopping)，norcanthesourcesofmovementforman

endlessseries(manforinstancebeingactedonbyair，airbythe

sun，thesunbyStrife，andsoonwithoutlimit)。Similarlythe

finalcausescannotgoonadinfinitum，-walkingbeingforthesake

ofhealth，thisforthesakeofhappiness，happinessforthesakeof

somethingelse，andsoonethingalwaysforthesakeofanother。And

thecaseoftheessenceissimilar。Forinthecaseof

intermediates，whichhavealasttermandatermpriortothem，the

priormustbethecauseofthelaterterms。Forifwehadtosaywhich

ofthethreeisthecause，weshouldsaythefirst；surelynotthe

last，forthefinaltermisthecauseofnone；noreventhe

intermediate，foritisthecauseonlyofone。(Itmakesnodifference

whetherthereisoneintermediateormore，norwhethertheyare

infiniteorfiniteinnumber。)Butofserieswhichareinfinitein

thisway，andoftheinfiniteingeneral，allthepartsdowntothat

nowpresentarealikeintermediates；sothatifthereisnofirst

thereisnocauseatall。

Norcantherebeaninfiniteprocessdownwards，withabeginning

intheupwarddirection，sothatwatershouldproceedfromfire，earth

fromwater，andsoalwayssomeotherkindshouldbeproduced。For

onethingcomesfromanotherintwoways-notinthesenseinwhich

’from’means’after’(aswesay’fromtheIsthmiangamescomethe

Olympian’)，buteither(i)asthemancomesfromtheboy，bytheboy’s

changing，or(ii)asaircomesfromwater。By’asthemancomesfrom

theboy’wemean’asthatwhichhascometobefromthatwhichis

comingtobe’or’asthatwhichisfinishedfromthatwhichisbeing

achieved’(forasbecomingisbetweenbeingandnotbeing，sothat

whichisbecomingisalwaysbetweenthatwhichisandthatwhichis

not；forthelearnerisamanofscienceinthemaking，andthisis

whatismeantwhenwesaythatfromalearneramanofscienceis

beingmade)；ontheotherhand，comingfromanotherthingaswater

comesfromairimpliesthedestructionoftheotherthing。Thisiswhy

changesoftheformerkindarenotreversible，andtheboydoesnot

comefromtheman(foritisnotthatwhichcomestobesomethingthat

comestobeasaresultofcomingtobe，butthatwhichexistsafter

thecomingtobe；foritisthusthattheday，too，comesfromthe

morning-inthesensethatitcomesafterthemorning；whichisthe

reasonwhythemorningcannotcomefromtheday)；butchangesofthe

otherkindarereversible。Butinbothcasesitisimpossiblethatthe

numberoftermsshouldbeinfinite。Fortermsoftheformerkind，

beingintermediates，musthaveanend，andtermsofthelatterkind

changebackintooneanother，forthedestructionofeitheristhe

generationoftheother。

Atthesametimeitisimpossiblethatthefirstcause，being

eternal，shouldbedestroyed；forsincetheprocessofbecomingisnot

infiniteintheupwarddirection，thatwhichisthefirstthingby

whosedestructionsomethingcametobemustbenon-eternal。

Further，thefinalcauseisanend，andthatsortofendwhich

isnotforthesakeofsomethingelse，butforwhosesakeeverything

elseis；sothatifthereistobealasttermofthissort，the

processwillnotbeinfinite；butifthereisnosuchterm，therewill

benofinalcause，butthosewhomaintaintheinfiniteseries

eliminatetheGoodwithoutknowingit(yetnoonewouldtrytodo

anythingifhewerenotgoingtocometoalimit)；norwouldthere

bereasonintheworld；thereasonableman，atleast，alwaysacts

forapurpose，andthisisalimit；fortheendisalimit。

Buttheessence，also，cannotbereducedtoanotherdefinition

whichisfullerinexpression。Fortheoriginaldefinitionisalways

moreofadefinition，andnotthelaterone；andinaseriesin

whichthefirsttermhasnottherequiredcharacter，thenexthas

notiteither。Further，thosewhospeakthusdestroyscience；forit

isnotpossibletohavethistillonecomestotheunanalysableterms。

Andknowledgebecomesimpossible；forhowcanoneapprehendthings

thatareinfiniteinthisway？Forthisisnotlikethecaseofthe

line，towhosedivisibilitythereisnostop，butwhichwecannot

thinkifwedonotmakeastop(forwhichreasononewhoistracing

theinfinitelydivisiblelinecannotbecountingthepossibilities

ofsection)，butthewholelinealsomustbeapprehendedby

somethinginusthatdoesnotmovefromparttopart-Again，nothing

infinitecanexist；andifitcould，atleastthenotionofinfinity

isnotinfinite。

Butifthekindsofcauseshadbeeninfiniteinnumber，then

alsoknowledgewouldhavebeenimpossible；forwethinkweknow，

onlywhenwehaveascertainedthecauses，thatbutthatwhichis

infinitebyadditioncannotbegonethroughinafinitetime。

Theeffectwhichlecturesproduceonahearerdependsonhis

habits；forwedemandthelanguageweareaccustomedto，andthat

whichisdifferentfromthisseemsnotinkeepingbutsomewhat

unintelligibleandforeignbecauseofitsunwontedness。Foritis

thecustomarythatisintelligible。Theforceofhabitisshownbythe

laws，inwhichthelegendaryandchildishelementsprevailoverour

knowledgeaboutthem，owingtohabit。Thussomepeopledonotlisten

toaspeakerunlesshespeaksmathematically，othersunlesshegives

instances，whileothersexpecthimtociteapoetaswitness。Andsome

wanttohaveeverythingdoneaccurately，whileothersareannoyedby

accuracy，eitherbecausetheycannotfollowtheconnexionofthought

orbecausetheyregarditaspettifoggery。Foraccuracyhas

somethingofthischaracter，sothatasintradesoinargumentsome

peoplethinkitmean。Henceonemustbealreadytrainedtoknowhowto

takeeachsortofargument，sinceitisabsurdtoseekatthesame

timeknowledgeandthewayofattainingknowledge；anditisnot

easytogetevenoneofthetwo。

Theminuteaccuracyofmathematicsisnottobedemandedinall

cases，butonlyinthecaseofthingswhichhavenomatter。Hence

methodisnotthatofnaturalscience；forpresumablythewholeof

naturehasmatter。Hencewemustinquirefirstwhatnatureis:for

thusweshallalsoseewhatnaturalsciencetreatsof(andwhether

itbelongstoonescienceortomoretoinvestigatethecausesandthe

principlesofthings)。

WEmust，withaviewtothesciencewhichweareseeking，first

recountthesubjectsthatshouldbefirstdiscussed。Theseinclude

boththeotheropinionsthatsomehaveheldonthefirstprinciples，

andanypointbesidesthesethathappenstohavebeenoverlooked。

Forthosewhowishtogetclearofdifficultiesitisadvantageous

todiscussthedifficultieswell；forthesubsequentfreeplayof

thoughtimpliesthesolutionofthepreviousdifficulties，anditis

notpossibletountieaknotofwhichonedoesnotknow。Butthe

difficultyofourthinkingpointstoa’knot’intheobject；forinso

farasourthoughtisindifficulties，itisinlikecasewiththose

whoarebound；forineithercaseitisimpossibletogoforward。

Henceoneshouldhavesurveyedallthedifficultiesbeforehand，both

forthepurposeswehavestatedandbecausepeoplewhoinquirewithout

firststatingthedifficultiesarelikethosewhodonotknowwhere

theyhavetogo；besides，amandoesnototherwiseknowevenwhether

hehasatanygiventimefoundwhatheislookingforornot；for

theendisnotcleartosuchaman，whiletohimwhohasfirst

discussedthedifficultiesitisclear。Further，hewhohasheard

allthecontendingarguments，asiftheywerethepartiestoacase，

mustbeinabetterpositionforjudging。

Thefirstproblemconcernsthesubjectwhichwediscussedinour

prefatoryremarks。Itisthis-(1)whethertheinvestigationofthe

causesbelongstooneortomoresciences，and(2)whethersucha

scienceshouldsurveyonlythefirstprinciplesofsubstance，or

alsotheprinciplesonwhichallmenbasetheirproofs，e。g。whether

itispossibleatthesametimetoassertanddenyoneandthesame

thingornot，andallothersuchquestions；and(3)ifthescience

inquestiondealswithsubstance，whetheronesciencedealswithall

substances，ormorethanone，andifmore，whetherallareakin，or

someofthemmustbecalledformsofWisdomandtheotherssomething

else。And(4)thisitselfisalsooneofthethingsthatmustbe

discussed-whethersensiblesubstancesaloneshouldbesaidtoexistor

othersalsobesidesthem，andwhethertheseothersareofonekind

orthereareseveralclassesofsubstances，asissupposedbythose

whobelievebothinFormsandinmathematicalobjectsintermediate

betweentheseandsensiblethings。Intothesequestions，then，aswe

say，wemustinquire，andalso(5)whetherourinvestigationis

concernedonlywithsubstancesoralsowiththeessentialattributes

ofsubstances。Further，withregardtothesameandotherandlikeand

unlikeandcontrariety，andwithregardtopriorandposteriorandall

othersuchtermsaboutwhichthedialecticianstrytoinquire，

startingtheirinvestigationfromprobablepremisesonly，-whose

businessisittoinquireintoallthese？Further，wemustdiscussthe

essentialattributesofthesethemselves；andwemustasknotonly

whateachoftheseis，butalsowhetheronethingalwayshasone

contrary。Again(6)，aretheprinciplesandelementsofthingsthe

genera，orthepartspresentineachthing，intowhichitis

divided；and(7)iftheyarethegenera，aretheythegenerathat

arepredicatedproximatelyoftheindividuals，orthehighest

genera，e。g。isanimalormanthefirstprincipleandthemore

independentoftheindividualinstance？And(8)wemustinquireand

discussespeciallywhetherthereis，besidesthematter，anything

thatisacauseinitselfornot，andwhetherthiscanexistapart

ornot，andwhetheritisoneormoreinnumber，andwhetherthere

issomethingapartfromtheconcretething(bytheconcretethingI

meanthematterwithsomethingalreadypredicatedofit)，orthere

isnothingapart，orthereissomethinginsomecasesthoughnotin

others，andwhatsortofcasestheseare。Again(9)weaskwhetherthe

principlesarelimitedinnumberorinkind，boththoseinthe

definitionsandthoseinthesubstratum；and(10)whetherthe

principlesofperishableandofimperishablethingsarethesameor

different；andwhethertheyareallimperishableorthoseof

perishablethingsareperishable。Further(11)thereisthequestion

whichishardestofallandmostperplexing，whetherunityand

being，asthePythagoreansandPlatosaid，arenotattributesof

somethingelsebutthesubstanceofexistingthings，orthisisnot

thecase，butthesubstratumissomethingelse，-asEmpedoclessays，

love；assomeoneelsesays，fire；whileanothersayswaterorair。

Again(12)weaskwhethertheprinciplesareuniversalorlike

individualthings，and(13)whethertheyexistpotentiallyor

actually，andfurther，whethertheyarepotentialoractualinany

othersensethaninreferencetomovement；forthesequestionsalso

wouldpresentmuchdifficulty。Further(14)，arenumbersandlinesand

figuresandpointsakindofsubstanceornot，andiftheyare

substancesaretheyseparatefromsensiblethingsorpresentin

them？Withregardtoallthesemattersnotonlyisithardtoget

possessionofthetruth，butitisnoteasyeventothinkoutthe

difficultieswell。