Fallacies.docx

Fallacies.docx

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Fallacies

Fallacies

Whatthishandoutisabout

Thishandoutisoncommonlogicalfallaciesthatyoumayencounterinyourownwritingorthewritingofothers.Thehandoutprovidesdefinitions,examples,andtipsonavoidingthesefallacies.

Arguments

Mostacademicwritingtasksrequireyoutomakeanargument—thatis,topresentreasonsforaparticularclaimorinterpretationyouareputtingforward.Youmayhavebeentoldthatyouneedtomakeyourargumentsmorelogicalorstronger.Andyoumayhaveworriedthatyousimplyaren'talogicalpersonorwonderedwhatitmeansforanargumenttobestrong.Learningtomakethebestargumentsyoucanisanongoingprocess,butitisn'timpossible:

"Beinglogical"issomethinganyonecando,withpractice!

Eachargumentyoumakeiscomposedofpremises（thisisatermforstatementsthatexpressyourreasonsorevidence）thatarearrangedintherightwaytosupportyourconclusion（themainclaimorinterpretationyouareoffering）.Youcanmakeyourargumentsstrongerby

1.usinggoodpremises（onesyouhavegoodreasontobelievearebothtrueandrelevanttotheissueathand）,

2.makingsureyourpremisesprovidegoodsupportforyourconclusion（andnotsomeotherconclusion,ornoconclusionatall）,

3.checkingthatyouhaveaddressedthemostimportantorrelevantaspectsoftheissue（thatis,thatyourpremisesandconclusionfocusonwhatisreallyimportanttotheissueyou'rearguingabout）,and

4.notmakingclaimsthataresostrongorsweepingthatyoucan'treallysupportthem.

Youalsoneedtobesurethatyoupresentallofyourideasinanorderlyfashionthatreaderscanfollow.Seeourhandoutsonargumentandorganizationforsometipsthatwillimproveyourarguments.

Thishandoutdescribessomewaysinwhichargumentsoftenfailtodothethingslistedabove;thesefailingsarecalledfallacies.Ifyou'rehavingtroubledevelopingyourargument,checktoseeifafallacyispartoftheproblem!

Itisparticularlyeasytoslipupandcommitafallacywhenyouhavestrongfeelingsaboutyourtopic—ifaconclusionseemsobvioustoyou,you'remorelikelytojustassumethatitistrueandtobecarelesswithyourevidence.Tohelpyouseehowpeoplecommonlymakethismistake,thishandoutusesanumberofcontroversialpoliticalexamples—argumentsaboutsubjectslikeabortion,guncontrol,thedeathpenalty,gaymarriage,euthanasia,andpornography.Thepurposeofthishandout,though,isnottoargueforanyparticularpositiononanyoftheseissues;rather,itistoillustrateweakreasoning,whichcanhappeninprettymuchanykindofargument!

Pleasebeawarethattheclaimsintheseexamplesarejustmade-upillustrations—theyhaven'tbeenresearched,soyoushouldn'tusethemasevidenceinyourownwriting.

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Whatarefallacies?

Fallaciesaredefectsthatweakenarguments.Bylearningtolookfortheminyourownandothers'writing,youcanstrengthenyourabilitytoevaluatetheargumentsyoumake,read,andhear.Itisimportanttorealizetwothingsaboutfallacies:

First,fallaciousargumentsarevery,verycommonandcanbequitepersuasive,atleasttothecasualreaderorlistener.Youcanfinddozensofexamplesoffallaciousreasoninginnewspapers,advertisements,andothersources.Second,itissometimeshardtoevaluatewhetheranargumentisfallacious.Anargumentmightbeveryweak,somewhatweak,somewhatstrong,orverystrong.Anargumentthathasseveralstagesorpartsmighthavesomestrongsectionsandsomeweakones.Thegoalofthishandout,then,isnottoteachyouhowtolabelargumentsasfallaciousorfallacy-free,buttohelpyoulookcriticallyatyourownargumentsandmovethemawayfromthe"weak"andtowardthe"strong"endofthecontinuum.

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Sowhatdofallacieslooklike?

Foreachfallacylisted,thereisadefinitionorexplanation,anexample,andatiponhowtoavoidcommittingthefallacyinyourownarguments.

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Hastygeneralization

Definition:

Makingassumptionsaboutawholegrouporrangeofcasesbasedonasamplethatisinadequate（usuallybecauseitisatypicalorjusttoosmall）.Stereotypesaboutpeople（"librariansareshyandsmart,""wealthypeoplearesnobs,"etc.）areacommonexampleoftheprincipleunderlyinghastygeneralization.

Example:

"Myroommatesaidherphilosophyclasswashard,andtheoneI'minishard,too.Allphilosophyclassesmustbehard!

"Twopeople'sexperiencesare,inthiscase,notenoughonwhichtobaseaconclusion.

Tip:

Askyourselfwhatkindof"sample"you'reusing:

Areyourelyingontheopinionsorexperiencesofjustafewpeople,oryourownexperienceinjustafewsituations?

Ifso,considerwhetheryouneedmoreevidence,orperhapsalesssweepingconclusion.（Noticethatintheexample,themoremodestconclusion"Somephilosophyclassesarehardforsomestudents"wouldnotbeahastygeneralization.）

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Missingthepoint

Definition:

Thepremisesofanargumentdosupportaparticularconclusion—butnottheconclusionthattheargueractuallydraws.

Example:

"Theseriousnessofapunishmentshouldmatchtheseriousnessofthecrime.Rightnow,thepunishmentfordrunkdrivingmaysimplybeafine.Butdrunkdrivingisaveryseriouscrimethatcankillinnocentpeople.Sothedeathpenaltyshouldbethepunishmentfordrunkdriving."Theargumentactuallysupportsseveralconclusions—"Thepunishmentfordrunkdrivingshouldbeveryserious,"inparticular—butitdoesn'tsupporttheclaimthatthedeathpenalty,specifically,iswarranted.

Tip:

Separateyourpremisesfromyourconclusion.Lookingatthepremises,askyourselfwhatconclusionanobjectivepersonwouldreachafterreadingthem.Lookingatyourconclusion,askyourselfwhatkindofevidencewouldberequiredtosupportsuchaconclusion,andthenseeifyou'veactuallygiventhatevidence.Missingthepointoftenoccurswhenasweepingorextremeconclusionisbeingdrawn,sobeespeciallycarefulifyouknowyou'reclaimingsomethingbig.

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Posthoc（alsocalledfalsecause）

ThisfallacygetsitsnamefromtheLatinphrase"posthoc,ergopropterhoc,"whichtranslatesas"afterthis,thereforebecauseofthis."

Definition:

AssumingthatbecauseBcomesafterA,AcausedB.Ofcourse,sometimesoneeventreallydoescauseanotheronethatcomeslater—forexample,ifIregisterforaclass,andmynamelaterappearsontheroll,it'struethatthefirsteventcausedtheonethatcamelater.Butsometimestwoeventsthatseemrelatedintimearen'treallyrelatedascauseandevent.Thatis,correlationisn'tthesamethingascausation.

Examples:

"PresidentJonesraisedtaxes,andthentherateofviolentcrimewentup.Jonesisresponsiblefortheriseincrime."Theincreaseintaxesmightormightnotbeonefactorintherisingcrimerates,buttheargumenthasn'tshownusthatonecausedtheother.

Tip:

Toavoidtheposthocfallacy,thearguerwouldneedtogiveussomeexplanationoftheprocessbywhichthetaxincreaseissupposedtohaveproducedhighercrimerates.Andthat'swhatyoushoulddotoavoidcommittingthisfallacy:

IfyousaythatAcausesB,youshouldhavesomethingmoretosayabouthowAcausedBthanjustthatAcamefirstandBcamelater!

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Slipperyslope

Definition:

Thearguerclaimsthatasortofchainreaction,usuallyendinginsomedireconsequence,willtakeplace,butthere'sreallynotenoughevidenceforthatassumption.Thearguerassertsthatifwetakeevenonestepontothe"slipperyslope,"wewillendupslidingallthewaytothebottom;heorsheassumeswecan'tstophalfwaydownthehill.

Example:

"Animalexperimentationreducesourrespectforlife.Ifwedon'trespectlife,wearelikelytobemoreandmoretolerantofviolentactslikewarandmurder.Soonoursocietywillbecomeabattlefieldinwhicheveryoneconstantlyfearsfortheirlives.Itwillbetheendofcivilization.Topreventthisterribleconsequence,weshouldmakeanimalexperimentationillegalrightnow."Sinceanimalexperimentationhasbeenlegalforsometimeandcivilizationhasnotyetended,itseemsparticularlyclearthatthischainofeventswon'tnecessarilytakeplace.Evenifwebelievethatexperimentingonanimalsreducesrespectforlife,andlossofrespectforlifemakesusmoretolerantofviolence,thatmaybethespotonthehillsideatwhichthingsstop—wemaynotslideallthewaydowntotheendofcivilization.Andsowehavenotyetbeengivensufficientreasontoacceptthearguer'sconclusionthatwemustmakeanimalexperimentationillegalrightnow.

Likeposthoc,slipperyslopecanbeatrickyfallacytoidentify,sincesometimesachainofeventsreallycanbepredictedtofollowfromacertainaction.Here'sanexamplethatdoesn'tseemfallacious:

"IfIfailEnglish101,Iwon'tbeabletograduate.IfIdon'tgraduate,Iprobablywon'tbeabletogetagoodjob,andImayverywellendupdoingtempworkorflippingburgersforthenextyear."

Tip:

Checkyourargumentforchainsofconsequences,whereyousay"ifA,thenB,andifB,thenC,"andsoforth.Makesurethesechainsarereasonable.

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Weakanalogy

Definition:

Manyargumentsrelyonananalogybetweentwoormoreobjects,ideas,orsituations.Ifthetwothingsthatarebeingcomparedaren'treallyalikeintherelevantrespects,theanalogyisaweakone,andtheargumentthatreliesonitcommitsthefallacyofweakanalogy.

Example:

"Gunsarelikehammers—they'rebothtoolswithmetalpartsthatcouldbeusedtokillsomeone.Andyetitwouldberidiculoustorestrictthepurchaseofhammers—sorestrictionsonpurchasinggunsareequallyridiculous."Whilegunsandhammersdosharecertainfeatures,thesefeatures（havingmetalparts,beingtools,andbeingpotentiallyuse