Critical-Thinking

CriticalThinkingAnIntroductionAlecFisherPublishedbythePressSyndicateoftheUNIVERSITYOFCAMBRIDGEThePittBuilding,TrumpingtonStreet,Cambridge,UnitedKingdomCAMBRIDGEUNIVERSITYPRESSTheEdinburghBuilding,CambridgeCB22RU,UK40West20thStreet,NewYork,NY10011–4211,USA477WilliamstownRoad,PortMelbourne,VIC3207,AustraliaRuizdeAlarcón13,28014Madrid,SpainDockHouse,TheWaterfront,CapeTown8001,SouthAfrica©CambridgeUniversityPress2001Thisbookisincopyright.Subjecttostatutoryexceptionandtotheprovisionsofrelevantlicensingagreements,noreproductionofanypartmaytakeplacewithoutthewrittenpermissionofCambridgeUniversityPress.Firstpublished2001PrintedintheUnitedKingdomattheUniversityPress,CambridgeTypefacesMeridienandFrutigerSystemQuarkXpress®AcataloguerecordforthisbookisavailablefromtheBritishLibraryISBN0521009847paperbackTypesetbyDorwynLtd,RowlandsCastle,HantsThecoverillustrationistheDisquietingMuses,1925(oiloncanvas),byGiorgiodeChirico(1888–1978),PrivateCollection/PeterWilli/BridgemanArtLibrary©DACS2001ContentsPrefacev1Whatiscriticalthinkingandhowtoimproveit12Identifyingreasonsandconclusions:thelanguageofreasoning153Understandingreasoning:differentpatternsofreasoning334Understandingreasoning:assumptions,contextandathinkingmap475Clarifyingandinterpretingexpressionsandideas616Theacceptabilityofreasons:includingtheircredibility797Judgingthecredibilityofsourcesskilfully938Evaluatinginferences:deductivevalidityandothergrounds1079Evaluatinginferences:assumptionsandotherrelevantarguments12410Reasoningaboutcausalexplanations13811Decisionmaking:options,consequences,valuesandrisks154Questionsappendix170Answerstoquestions201Glossary235Bibliography243Index245WhatiscriticalthinkingandhowtoimproveitInrecentyears‘criticalthinking’hasbecomesomethingofa‘buzzword’ineducationalcircles.Formanyreasons,educatorshavebecomeveryinterestedinteaching‘thinkingskills’ofvariouskindsincontrastwithteachinginformationandcontent.Ofcourse,youcandoboth,butinthepasttheemphasisinmostpeople’steachinghasbeenonteachingcontent–history,physics,geographyorwhatever–and,thoughmanyteacherswouldclaimtoteachtheirstudents‘howtothink’,mostwouldsaythattheydothisindirectlyorimplicitlyinthecourseofteachingthecontentwhichbelongstotheirspecialsubject.Increasingly,educatorshavecometodoubttheeffectivenessofteaching‘thinkingskills’inthisway,becausemoststudentssimplydonotpickupthethinkingskillsinquestion.Theresultisthatmanyteachershavebecomeinterestedinteachingtheseskillsdirectly.Thisiswhatthistextaimstodo.Itteachesarangeoftransferablethinkingskills,butitdoessoexplicitlyanddirectly.Theskillsinquestionarecriticalthinkingskills(sometimescalledcritico-creativethinkingskills–forreasonsexplainedbelow),andtheywillbetaughtinawaythatexpresslyaimstofacilitatetheirtransfertoothersubjectsandothercontexts.Ifyoulearn,forexample,howtostructureanargument,judgethecredibilityofasourceormakeadeci-sion,bythemethodsweshallexplaininafewcontexts,itwillnotbedifficulttoseehowtodothesethingsinmanyothercontextstoo;thisisthesenseinwhichtheskillsweteachinthistextare‘transferable’.Itcanbedangerousforaneducationalideatobecomefashionable,becauseitgetspulledinmanydirectionsandcanloseitsfocus,sowebeginbyexplainingtheideaof‘criticalthinking’asithasdevelopedoverthelast100years.1Pleasewritedownwhatyou(thereader)thinkthephrase‘criticalthinking’means.Youwillhavehearddifferentusesofthephraseinvariouscontexts,sopulltogetherwhatmakessensetoyoufromthoseuses.Evenifyouhaveverylittleidea,dothebestyoucan.Atthisstagetherearenorightorwronganswers.Youranswerisforyoualone–sothatyoucancompareitwithwhatweareabouttotellyou.1.1Someclassicdefinitionsfromthecriticalthinkingtradition1.1.1JohnDeweyand‘reflectivethinking’Infact,peoplehavebeenthinkingabout‘criticalthinking’andhavebeenresearchinghowtoteachitforaboutahundredyears.Inaway,Socratesbeganthisapproachtolearningover2,000yearsago,butJohnDewey,theAmericanphilosopher,psychologistandeducator,iswidelyregardedasthe‘father’ofthemoderncriticalthinkingtradition.Hecalledit‘reflectivethinking’anddefineditas:Active,persistent,andcarefulconsiderationofabelieforsup-posedformofknowledgeinthelightofthegroundswhichsupportitandthefurtherconclusionstowhichittends.(Dewey,1909,p.9)Letusspendamomentunpackingthisdefinition.Bydefiningcriti-calthinkingasan‘active’process,Deweyiscontrastingitwiththekindofthinkinginwhichyoujustreceiveideasandinformationfromsome-oneelse–whatyoumightreasonablycalla‘passive’process.ForDewey,andforeveryonewhohasworkedinthistraditionsubse-quently,criticalthinkingisessentiallyan‘active’process–oneinwhichyouthinkthingsthroughforyourself,raisequestionsyourself,findrelevantinformationyourself,etc.ratherthanlearninginalargelypas-sivewayfromsomeoneelse.Indefiningcriticalthinkingas‘persistent’and‘careful’Deweyiscontrastingitwiththekindofunreflectivethinkingweallengageinsometimes,forexamplewhenwe‘jump’toaconclusionormakea‘snap’decisionwithoutthinkingaboutit.Sometimes,ofcourse,wehavetodothisbecauseweneedtodecidequicklyortheissueisnotimportantenoughtowarrantcarefulthought,butofte