3 1 0
C H A P T E R 1 5 ■ F a l l a c i e s o f R e l e v a n c e
Cliff’sattackmightormightnotbejustified.IftheonlyreasonwhyNorm
favorsnormalrelationsbetweentheUnitedStatesandCubaisthatthis
wouldenableNormtomakemoremoney,thenCliff’sadhominemattack
iswellfounded.ButifNorm’srealreasonforsayingwhathedoesisthat
hehonestlybelievesthatnormalrelationswouldbebeneficialbothtothe
UnitedStatesandtoCuba,thenNorm’spositiondoesnotdependonany
lackofintegrity.Inthatcase,Cliff’sattackisnotwellfounded,evenifitso
happensthatNormwouldprofitfromnormalrelations.
Whetherjustifiedornot,adhominemargumentsofthisthirdvarietycan
becalleddismissers,becausetheydismissthespeakerasuntrustworthyand
unreliable.Theirpointisnottodenythetruthoftheclaimorthespeaker ’s
righttosayit.Instead,adismisserissupposedtoshowwhythefactthat
thisspeakersupportsaclaimisnotagoodreasontobelievethatclaim(orto
denyit,forthatmatter).
Thesethreevariationsarealladhominemargumentsbecausetheystart
frompremisesabouttheperson’scharacterorstatus.Wheretheydifferis
intheirconclusions:Deniersconcludethataclaimisuntrueorthatanargu-
mentisunsoundorweak.Silencersconcludethatsomeonelackstherightto
speakinacertaincontext.Dismissersconcludethatsomeoneisuntrustwor-
thyorunreliable.Eachcanbeeitherjustifiedorunjustified,soadhominems
comeinsixkindsthatcanbediagrammedlikethis:
Ad Hominem Arguments Justified Not Justified
Deniers Louie, the hired perjurer Shabby protesters
Silencers Tad if he is not a legislator Tad if he is a legislator
Dismissers Cliff’s reply if Norm lacks Cliff’s reply if Norm
integrity does not lack integrity
Whatlogiciansusuallycalladhominemfallaciesareunjustifieddeniers.
Evenwhenthepremisesofsuchanargumentaretrue,theyareirrelevantto
theconclusion.Thatmakesthemfallaciesofrelevance.Onceyougetusedto
spottingadhominemfallacies,theyseemcommonandobvious.
Whenassessinganadhominemargument,thefirststepistodetermine
whetheritsconclusionisaboutsomeone’srighttospeak,aboutsomeone’s
reliability,oraboutthetruth,soundness,orstrengthofwhatisclaimed.The
secondstepistodeterminewhetheritspremisesprovideadequatejustifica-
tionforitsconclusion.Thesestepswillenableyoutoplacetheargumentin
theabovetable,buttheywilloftenbeneithereasynorobvious.Although
perjurersforhirealmostalwayslie,mostpeopleexhibitsomemiddlingde-
greeofreliability.Whenpeopleareknownforpassingonrumorswithout
checkingtheirtruth,thismightbeareasontodoubtwhattheysaywhen
theypassonyetanotherrumor(evenifitisnotareasontobelievethatwhat
theysayisfalse).Inassessingwhattheysay,itwouldbebesttolookforad-
ditionalevidence.Ifnoneisavailable,thenweneedtoaskhowoftentheir
testimonyistrueonmattersofthiskind.Onlybycarefulinspectionofindi-
vidualcasescanwedeterminethestrengthofsuchadhominemarguments.
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