GRE課件邏輯錯(cuò)誤PART1

常見邏輯錯(cuò)誤

及分析方法邏輯錯(cuò)誤類型一覽一，調(diào)查數(shù)據(jù)相關(guān)(evidence)二，因果關(guān)系類(assumption/conclusion)三，比較類比(evidence)四，改變范圍類（evidence）五，對策的充分性與必要性(assumption/conclusion)六，其它一，調(diào)查數(shù)據(jù)相關(guān)(evidence)Problemsconcerningdata一，調(diào)查數(shù)據(jù)相關(guān)(evidence)1.有偏采樣S2.不充分采樣S3.實(shí)驗(yàn)對比4.百分比陷阱5.質(zhì)疑權(quán)威S6.模棱兩可S1.有偏采樣SThebiased-samplefallacy根據(jù)最新研究顯示，80%的日本男性覺得鳳姐就是他們夢寐以求的妻子。所以。。。鳳姐必定在中國男人中大受歡迎！ExampleInarecentsurveyconductedbyWallStreetWeekly,80%oftherespondentsindicatedtheirstrongdisapprovalofincreasedcapitalgainstaxes.Thissurveyclearlyshowsthatincreasedcapitalgainstaxeswillmeetwithstrongoppositionfromtheelectorate.基本錯(cuò)誤模型比較---抽樣中的對象和結(jié)論中的對象Sample------Conclusion

Theconclusionunjustifiablyreliesonthesurvey/poll/studythat_________.80%oftherespondentsindicatedtheirdisapprovalofincreasedcapitalgainstaxesHowever,therespondentsofthesurvey/investigation/pollaredifferentfromthetargetintheconclusioninnature,sothedatadrawnfromthesurveyareunrepresentativetosupportwhatthearguerclaims.ExercisesAccordingtoarecentsurvey,78%ofhighschoolstudentsshowtheirgreatinterestinextracurricularactivities.Therefore,theextracurricularactivitiesorganizedbythestudentunionmustbeverypopularwiththelocalcollegestudents.請注意：此類錯(cuò)誤和調(diào)查的對象有關(guān)，和數(shù)據(jù)無關(guān)！2.不充分采樣STheinsufficient-samplefallacyIusedtohave3boyfriendsandfoundthemtobeirresponsibleandrude.Itisobviousthatmenareevil.

Example1Accordingtoasurveyof500urbanresidents,theprevalenceofstressheadachesincreaseswitheducationallevel,sothatstressheadachesoccurmostoftenamongpeoplewithhigherdegreesinPalmTreeCity.MODEL關(guān)鍵：無對象總數(shù)假設(shè)合理性假設(shè)不合理性Thesamplemightbetoosmalltorepresentative點(diǎn)出錯(cuò)誤的關(guān)鍵thestatisticscitedmaybemisleadingbecausethetotalnumberof___isnotspecified.Theurbanresidents假設(shè)合理性Forexample,if_____,thefactthat______providesstrongsupportfortheconclusion.Thecityhas800residents500ofthemreporttheirstressheadachesduetoincreasingeducationallevel假設(shè)不合理性O(shè)ntheotherhand,if_____,theconclusionismuchweakened.Thecityhas80000000residentsExample2Thecommonnotionthatworkersaregenerallyapatheticaboutmanagementissueisfalse,oratleastoutdated:arecentlypublishedsurveyindicatesthat79%ofthenearly1200workerswhorespondedtosurveyquestionnairesexpressedahighlevelofinterestinthetopicsofcorporaterestructuringandredesignofbenefitsprograms.請注意：此類錯(cuò)誤和具體的數(shù)據(jù)有關(guān)，和百分比以及對象無關(guān)。3.實(shí)驗(yàn)對比

Test&ControlGroupFallacyWhethertestgroupandcontrolgroupareofthesamenature???基本錯(cuò)誤模型TobesubjectiveTobeobjectiveThingsarewhattheyare.Becausewethinktheyare."Doctorshavelongsuspectedthatsecondaryinfectionsmaykeepsomepatientsfromhealingquicklyafterseveremusclestrain.Thishypothesishasnowbeenprovedbypreliminaryresultsofastudyoftwogroupsofpatients.Thefirstgroupofpatients,allbeingtreatedformuscleinjuriesbyDr.Newland,adoctorwhospecializesinsportsmedicine,tookantibioticsregularlythroughouttheirtreatment.Theirrecuperationtimewas,onaverage,40percentquickerthantypicallyexpected.

Patientsinthesecondgroup,allbeingtreatedbyDr.Alton,ageneralphysician,weregivensugarpills,althoughthepatientsbelievedtheyweretakingantibiotics.Theiraveragerecuperationtimewasnotsignificantlyreduced.Therefore,allpatientswhoarediagnosedwithmusclestrainwouldbewelladvisedtotakeantibioticsaspartoftheirtreatment."MODELExceptadoptingdifferentmedicines:Ageandhealth?Severityofthedisease?Othertherapiesexceptthemedicine?Backgroundsofthetwodoctors?Theresultofthestudycanonlybeprovedwhensomecriticalpreconditionshavebeenmet!提出第一種可能性Aboveall,itdoesnottakeintoaccountthepossibilitythat…Twogroupsofpatientshavedifferenthealthconditions.Supposethefirstgroupconsistsofonlyyoungpeoplebutthesecondgroupofoldones.What’smore,theargueralsofailstoruleoutthepossibilitythat_____Thetwodoctorsofdifferentbackgroundsmightadoptdifferenttherapiesandtreatment,whichmightequallyaffecttherecuperationtime.4.百分比陷阱

FalseRatioFallacy小月月今年長胖了20%杜老師今年長胖了5%很明顯，今年小月月長的肉比杜老師多多了。SMM---50DLS---10001050基本錯(cuò)誤模型百分比無意義，沒有基數(shù)：nobaseamount百分比陷阱往往企圖用比率的變化來掩飾絕對數(shù)量的變化A的百分比比B高，說明A比B多好強(qiáng)A的百分比比B低，說明A比B少壞弱Accordingtoapollof200charitableorganizations,donationsofmoneytononprofitgroupsincreasedbynearly25percentlastyear,thoughnotallcharitiesgainedequally.Religiousgroupsgainedthemost(30percent),followedbyenvironmentalgroups(23percent),whereaseducationalinstitutionsexperiencedonlyaverysmallincreaseindonations(3percent).Thispollindicatesthatmorepeoplearewillingandabletogivemoneytocharitiesbutthatfundingforeducationisnotapriorityformostpeople.Thesedifferencesindonationratesmustresultfromtheperceptionthateducationalinstitutionsarelessinneedofdonationsthanareotherkindsofinstitutions.

MODEL假設(shè)百分比小的基數(shù)較大，則實(shí)際值較大假設(shè)百分比大的基數(shù)較小，則實(shí)際值較小結(jié)論被推翻引出分析Lackingmorespecificinformationaboutbaseamount,itisimpossibletoassessthereliabilityofthesurvey’sresults.假設(shè)并比較基數(shù)Supposethebaseamountof_____is_______,thenevenif______,_______.假設(shè)百分比小的對象基數(shù)可能很大However,itisquitelikelythatthebaseamountof___ismerely,andevenif____,______.假設(shè)百分比大的對象基數(shù)可能很小Therefore,theargumentisstronglyweakened.Supposethebaseamountofthefundofeducationinstitutionsis100milliondollars,thenevenifthereismerelya3%increase,itis3milliondollars.However,itisquitelikelythatthebaseamountofthefundofenvironmentalandreligiousgroupsismerely10thousandand20thousand,andevenifthereisa30%&23%increase,itissimply3thousandand4.6thousand.Therefore,theargumentisstronglyweakened.請注意：此類錯(cuò)誤只和無基數(shù)的百分比有關(guān)系，和其它數(shù)據(jù)對象無關(guān)。5.質(zhì)疑權(quán)威S

False-AuthorityFallacy調(diào)查的權(quán)威性值得質(zhì)疑,何人,何時(shí),何地進(jìn)行,是否真正權(quán)威?

Theargumentusestheword______,butitfailstoprovidesufficientevidencetojustifytheauthorityoftheresearchersconductedtheresearch/theaccuracyoftheresearch.EXERCISES244650請注意：此類錯(cuò)誤只和表示權(quán)威的詞語有關(guān)系，和其它無關(guān)。6.模棱兩可SThefallacyofequivocation論者用一些模糊的量詞,如很多，更好，大量,絕大多數(shù),最高等等來描述數(shù)量,這使得人們很難估計(jì)實(shí)際數(shù)量到底是多少.ExampleTheCumquatCafemadeamistakeinmovingtoanewlocation.Afteroneyearatthenewspot，itisdoingaboutthesamevolumeofbusinessasbefore，buttheownersoftheRoboWrenchplumbingsupplywholesaleoutletthattookoveritsoldlocationareapparentlydoingbetter：RoboWrenchisplanningtoopenastoreinaneighboringcity.Theword____inthestatementthat______istoovaguetobemeaningful.However,thearguerfailstoprovideasecondtermtoclarifytheblur.EXERCISE2388109二，因果關(guān)系類

(assumption/conclusion)CausalRelationship1.急于概括2.后此謬誤3.因果倒置S1.急于概括

Hasty-GeneralizationFallacyAndytookMeibaoyuanfor2monthsandbecamemuchmoreslimthaneverbefore.Therefore,ifyouwanttoloseweight,takeMeibaoyuan.基本錯(cuò)誤模型A----BConclusionExampleTheCumquatCafebeganadvertisingonourlocalradiostationthisyearandwasdelightedtoseeitsbusinessincreaseby10percentoverlastyear’stotals.Theirsuccessshowsyouhowyoucanuseradioadvertisingtomakeyourbusinessmoreprofitable.MODEL原因結(jié)果原因2原因3原因4復(fù)述原文的原因和結(jié)論Thearguerassumesthat_________.RadioadvertisingalonehascausedtheincreaseinbusinessattheComquatCafe.提出其它可能的原因Thisassumptionisquestionablebecauseitoverlooksanumberofotherfactors.Forexample,________TheComquatmighthavechangedownersorchefs.ItmighthavelaunchedcouponadcampaignItmighthavechangedorupdatedthemenu.Inthepast,thebodystylesofPatriotcarshavebeenold-fashioned,andourcarshavenotsoldaswellashaveourcompetitors'cars.Thus,weshoulddiscontinueouroldestmodelsandconcentrateinsteadonmanufacturingsportycars.Post-saleserviceHighfuelconsumptionEngineperformanceAutomotivetrimSecurityMarketingstrategiesPreviousexperiencehasshownthatourstoresaremostprofitableinareaswhereresidentsarehighlyconcernedwithleadinghealthylives.WeshouldthereforebuildournextnewstoreinPlainsville,whichhasmanysuchresidents.Plainsvillemerchantsreportthatsalesofrunningshoesandexerciseclothingareatall-timehighs.(88)Inthefirstplace,theargumentisbasedonafallacyofhastygeneralization.ThearguerassumesthatPlainvilleresidents’concernwithleadinghealthylives

hasgivenriseto

theboomingsaleofrunningshoesandexerciseclothing.

Theassumptionisquestionablebecausethearguerfailstoruleoutotherpossibilities.Forexample,Plainsvilleresidentspreferwearingsportswearsimplyduetothereasonoftheweathercondition.What’smore,sportswearmightbemorecomfortableandlessexpensivecomparedtoothertypeofclothing.請注意：此類錯(cuò)誤只和因果關(guān)系有關(guān)（原因—結(jié)論），和其它無關(guān)2.后此謬誤The“Afterthis,therefore”fallacy一下雨，動車就追尾了。所以，再下雨，所有動車都會追尾的！作者的推斷是建立在一個(gè)錯(cuò)誤的邏輯關(guān)系上的而這個(gè)邏輯關(guān)系就是作者基于時(shí)間先后所錯(cuò)誤得出的因果關(guān)系。因此，我們這里要駁斥這種關(guān)系！基本錯(cuò)誤模型INCIDENT1INCIDENT2PASTPRESENTCAUSALThesequenceoftime

標(biāo)志詞：afterthissincethenwhenagoExampleAfteropeningthenewswimmingpoolearlylastsummer,TakeHeartsawa12percentincreaseintheuseofthecenterbymembers.

（錯(cuò)誤的因果關(guān)系）Therefore,inordertoincreasethenumberofourmembers,weshouldcontinuetoaddnewrecreationalfacilitiesinsubsequentyears:forexample,amultipurposegameroom,atenniscourt,andaminiaturegolfcourse.（作者的推斷）點(diǎn)出邏輯關(guān)系Thearguerassumesthat___caused_____.TheopeningofthenewswimmingpoolTheincreaseintheuseofthecenter提出其它可能性Thecausalclaimbasedonthecorrelationisprematureunlessthearguercanruleoutotherfactors.Forexample,______otherfitnesscentersmightgobankruptatthattimeItmightbeextremelyhotatthattime,somorepeoplethanevercometothecentertoswim.EXERCISE1297Irecommendthisseminarbecauseitislikelytobeawiseinvestment,giventhattheautomobileracingindustryrecentlyreportedthattheperformanceofitsmaintenancecrewsimprovedmarkedlyaftertheircrewshadattendedtheseminar.First,thearguercommitsafallacyofposthoc,ergopropterhoc.Heunfairlyassumesthattheseminarhascausedthemarkedimprovementof

theperformanceofthemaintenancecrews.Thecausalclaimbasedonthecorrelationisprematureunlessthearguercanruleoutotherfactors.Forexample,thecrewsmayhaveworkedharder.Moreover,thetechnologyofinspectingandmaintainingmayhavebeendeveloped.Inaddition,theinspectionrequirementsmaybemorestringent.請注意：“后此謬誤”是“急于概括”的變體，也包含有因果關(guān)系。但是這個(gè)錯(cuò)誤中必需包含時(shí)間上的前后關(guān)系。3.因果倒置SThefallacyofconfusingthecauseandtheeffect經(jīng)過調(diào)查：杜老師每天都喝2斤酒，他的酒量十分了得。因此，如果要增長你的酒量，每天最好都來2斤。每天2斤------------------酒量大事實(shí)上，天生酒量就大，才能喝二斤。基本錯(cuò)誤模型A---BCONCLUSIONB---AOfthosewhoresponded,themenwhoreportedthattheyengagedinvigorousoutdoorexercisenearlyeverydaylivedlongerthanthemenwhoreportedthattheyexercisedmildlyonlyonceortwiceaweek.Giventheclearlinkthatthisstudyestablishesbetweenlongevityandexercise,doctorsshouldnotrecommendmoderateexercisetotheirpatientsbutshouldinsteadencouragevigorousoutdoorexerciseonadailybasis.Thearguerassumesthat____causes_____.However,itislikelythatjustbecause_____,______.Thearguerassumesthatvigorousexercisescausetheirlongevity.However,itislikelythatjustbecauseofagoodphysicalcondition,theytakevigorousexercises.三，比較類比(evidence)AnalogyandComparison1.錯(cuò)誤類比S2.同等謬誤1.錯(cuò)誤類比S

ThefallacyoffaultyanalogyAndyandFurongSisterbothexcelatdancing.SinceFurongisawoman,itislikelythatAndyisawomantoo.基本錯(cuò)誤模型對象A對象B交集CONCLUSIONExampleTheCumquatCafemadeamistakeinmovingtoanewlocation.Afteroneyearatthenewspot，itisdoingaboutthesamevolumeofbusinessasbefore，buttheownersoftheRoboWrenchplumbingsupplywholesaleoutletthattookoveritsoldlocationareapparentlydoingbetter：RoboWrenchisplanningtoopenastoreinaneighboringcity.Aretheysimilarenough?點(diǎn)出文中的類比關(guān)系Theargumentrestsonfaultyanalogybetween____and____.CumquatCafeRoboWrench點(diǎn)出類比關(guān)系中的同和異Althoughtheybothhavethesimilaritythat____,wecannotneglecttheessentialdifferencethat____tomakethecomparisonnonsense.TheyusedtochoosethesamespotTheyareengagedindifferentbusiness2.同等謬誤TheAllThingsAreEqualFallacy杜老師去年贏得了超級女聲第一名.

今年，杜老師是應(yīng)該還會得第一.基本錯(cuò)誤模型假設(shè)事件發(fā)生的條件和背景不隨著時(shí)間和地點(diǎn)的變化而改變。

過去=將來A地=B地不同時(shí)間/不同地點(diǎn)-----產(chǎn)生同樣結(jié)果那有人會問:它和錯(cuò)誤類比有什么區(qū)別？區(qū)別很簡單，請看以下陳述小明去年得了三好學(xué)生，因此今年他還會得莫非這里的共同點(diǎn)是，去年和今年---他都是他自己？Sevenyearsago,homeownersinnearbyBrookvillecommunityadoptedasetofrestrictionsonhowthecommunity’syardsshouldbelandscapedandwhatcolorstheexteriorsofhomesshouldbepainted.Sincethen,averagepropertyvalueshavetripledinBrookville.InordertoraisepropertyvaluesinDeerhavenAcres,weshouldadoptourownsetofrestrictionsonlandscapingandhousepainting.MODEL同等推斷

不成立原因1不成立原因2不成立原因3提出文章中的同等推斷Thearguerclaimsthat_____because______.ThearguerclaimsthatDeerhavenAcresshouldadoptrestrictionsonlandscapingandhousingpaintingbecausethenearbyBrookvilleadoptedthem7yearsagoandtheirpropertyvaluestripled.指出這個(gè)推斷是有問題的Thisisanunwarrantedassumptionbecausethingsrarelyremainthesamefromplacetoplace/overextendedperiodsoftime.指出推斷不成立的可能性Importantfactorscannotbedeniedforas_______Brookville’sraiseinpropertyvaluesmightresultfortourism,foreigninvestmentorevenfoameconomy.ItislikelythatinBrookvillethelandscapingandhousepaintingisindisorderedcondition,neitherisDeerhavenAcres.結(jié)尾Allthesefactorsmentionedabovecanservetoweakenthearguer’claim.四，改變范圍類（evidence）Changingscope1.整體推個(gè)體S2.偷換概念1.整體推個(gè)體SThegeneraldoesn’tequalaspecificfallacy根據(jù)統(tǒng)計(jì)和調(diào)查，全國的男同胞都會娶女人為妻。因此，杜老師也會娶女人。整體情況不等于個(gè)體情況，因?yàn)榭赡艽嬖趀xception.MayorBrownwasrecentlyre-electedbyaclearmajorityof52percentofMonroetown‘svoters.Herre-election,however,doesnotshowthatmostpeopleinourtownfavoredMayorBrown’sproposalfortaxreductionoverthatofheropponent,Mr.Greene,whoproposedraisingtaxestoimproveeducation.Thisisclearlybecausevotersnationwidetendtore-electpeoplealreadyinoffice,regardlessofcandidates'proposals.提出文中的關(guān)系Theauthorunfairlyassumesthatthenationwidetendencyappliesspecificallyto_______TheauthorunfairlyassumesthatthenationwidetendencyappliesspecificallytoMonroetownresidents.指出和整體存在差異的可能性Lackingevidencethat個(gè)體reflectthisgeneraltendency,itisentirelypossiblethat與整體相反可能性./thetrendof_____mightbejusttheoppositeLackingevidencethatMonreotownresidents

reflectthisgeneraltendency,itisentirelypossiblethattheyvotestrictlywithfullconsideration./thetrendofMonreotownmightbejusttheoppositeEXERCISE1742.偷換概念A(yù)fallacyofinconsistentconnotationandextension什么是好男人？為了成為一個(gè)“好男人”，杜老師決定堅(jiān)持增發(fā)減肥掙錢基本錯(cuò)誤模型比較題目中所出現(xiàn)的概念和其定義是否是能夠匹配的。這個(gè)概念是否存在其它更合理的定義？

好男人？頭發(fā)長，苗條，有錢senseofresponsibilityrational概念定義ExampleInMegalopolis,thenumberoflawschoolgraduateswhowenttoworkforlarge,corporatefirmsdeclinedby15percentoverthelastthreeyears,whereasanincreasingnumberofgraduatestookjobsatsmall,generalpracticefirms.Eventhoughlargefirmsusuallyoffermuchhighersalaries,lawschoolgraduatesarechoosingtoworkforthesmallerfirmsmostlikelybecausetheyexperiencegreaterjobsatisfactionatsmallerfirms.Inasurveyoffirst-yearstudentsataleadinglawschool,mostagreedwiththestatementthatearningahighsalarywaslessimportanttothemthanjobsatisfaction.Thisfindingsuggeststhatt