3 1 1
A d H o m i n e m A r g u m e n t s
Inconsistency
Arelatedkindofargumentoccurswhensomeoneisaccusedofinconsist-
encyovertime.Ifyourneighborsaysthatthebesttimetoprunerosesisin
theautumn,butthenextspringshetellsyouthatthespringisthebesttime
topruneroses,thenthisinconsistencywouldgiveyousomereasontodoubt
herexpertiseasagardener.Maybeoverthewintershegotnewinforma-
tionthatchangedhermind,butherreliabilityisinquestionuntilyouhave
someexplanationofwhyshewouldsaydifferentthingsatdifferenttimes.If
shewaversbetweencontrarypositions,thennomorethanhalfofherviews
canbecorrect,soyouhavereasontoaskyourneighbor,“Whyhaveyou
changedyourtune?”and“WhyshouldItrustyounow?”
Whatsheissayingnowstillmightbecorrect.Maybespringistherighttime
topruneroses.Moreover,ifshegaveanargumentforherclaim(suchasthat
prunedrosesgrowbackmorequicklyinthespring,anditisbettertopruneroses
whentheygrowbackmorequickly),thenthatargumentstillmightbesound.
Hercurrentclaimandargumentdonotdependonwhatshesaidlastfall.For
thisreason,itisnormallyafallacytorejectpeople’sviewsonthebasisofanin-
consistencywiththeirviewsatothertimes.Maybetheyarerightthistime.Their
currentpositionsneedtobeassessedastheystandnow.(Whetherwewantpo-
liticalleaderswhoseviewsblowwiththewindis,ofcourse,anotherissue.)
Adifferentkindofinconsistencyoccursinthetraditionalfallacycalled
tu quoque,aLatintermthatmeans“youareanother.”Whenaparenttellsa
childtoquitsmoking,thechildmightrespond,“Lookwho’stalking.You’ve
beensmokingforyears.Ifit’ssobad,whydon’tyoustop?”Theforceofthis
chargemightbejustthattheparentishypocriticalorthatonehasnoright
tocriticizeothersfordoingsomethingthatonedoesoneself.Ifthatisthe
point,thenthisresponseisasilencer,anditmightormightnotbejustified.
Inanycase,theparent’ssmokingdoesnotgiveanyreasonatalltoconclude
thatsmokingisnotbad.Touseatu quoqueargumenttoreachthatconclusion
wouldbeanunjustifieddenier(andanadhominemfallacy).Evenhypo-
critescanmaketrueclaimsandgivegoodarguments.Thus,toshowthat
someone’sclaimsandargumentsaredefective,onenormallyneedstolook
atthoseclaimsandargumentsthemselves,notatthebehaviorofthespeaker.
Genetic Fallacies
Insteadofcitingpastbeliefsoractsofaspeaker,someadhominemarguments
aimatthesourceororiginofthespeaker’sbelief.StephenColbert,forexam-
ple,dismissesscientistsbyexplaininghowtheygotcaughtupinscience:
“They’rephysicallyawkwardandlonely,sotheyspenttheiradolescence
downbythecreekstudyingthecreaturesthatlivethere.‘Imayberidiculed
atschool,’theythink,‘butacrawfishwouldneverjudgeme.’”^2 Thisparody,
ofcourse,issupposedtoshowhowsillyitistorejectsciencebecauseofits
origin(evenifthisoriginwereplausible).Whenitsoriginisirrelevanttothe
truthofaclaim,suchargumentscommitwhatiscalledthegenetic fallacy.
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