常見邏輯錯誤

及分析方法邏輯錯誤類型一覽一，調查數據相關(evidence)二，因果關系類(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，調查數據相關(evidence)Problemsconcerningdata一，調查數據相關(evidence)1.有偏采樣S2.不充分采樣S3.實驗對比4.百分比陷阱5.質疑權威S6.模棱兩可S1.有偏采樣SThebiased-samplefallacy根據最新研究顯示，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.基本錯誤模型比較---抽樣中的對象和結論中的對象Sample------Conclusion

Theconclusionunjustifiablyreliesonthesurvey/poll/studythat_________.80%oftherespondentsindicatedtheirdisapprovalofincreasedcapitalgainstaxesHowever,therespondentsofthesurvey/investigation/pollaredifferentfromthetargetintheconclusioninnature,sothedatadrawnfromthesurveyareunrepresentativetosupportwhatthearguerclaims.ExercisesAccordingtoarecentsurvey,78%ofhighschoolstudentsshowtheirgreatinterestinextracurricularactivities.Therefore,theextracurricularactivitiesorganizedbythestudentunionmustbeverypopularwiththelocalcollegestudents.請注意：此類錯誤和調查的對象有關，和數據無關！2.不充分采樣STheinsufficient-samplefallacyIusedtohave3boyfriendsandfoundthemtobeirresponsibleandrude.Itisobviousthatmenareevil.

Example1Accordingtoasurveyof500urbanresidents,theprevalenceofstressheadachesincreaseswitheducationallevel,sothatstressheadachesoccurmostoftenamongpeoplewithhigherdegreesinPalmTreeCity.MODEL關鍵：無對象總數假設合理性假設不合理性Thesamplemightbetoosmalltorepresentative點出錯誤的關鍵thestatisticscitedmaybemisleadingbecausethetotalnumberof___isnotspecified.Theurbanresidents假設合理性Forexample,if_____,thefactthat______providesstrongsupportfortheconclusion.Thecityhas800residents500ofthemreporttheirstressheadachesduetoincreasingeducationallevel假設不合理性Ontheotherhand,if_____,theconclusionismuchweakened.Thecityhas80000000residentsExample2Thecommonnotionthatworkersaregenerallyapatheticaboutmanagementissueisfalse,oratleastoutdated:arecentlypublishedsurveyindicatesthat79%ofthenearly1200workerswhorespondedtosurveyquestionnairesexpressedahighlevelofinterestinthetopicsofcorporaterestructuringandredesignofbenefitsprograms.請注意：此類錯誤和具體的數據有關，和百分比以及對象無關。3.實驗對比

Test&ControlGroupFallacyWhethertestgroupandcontrolgroupareofthesamenature???基本錯誤模型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基本錯誤模型百分比無意義，沒有基數：nobaseamount百分比陷阱往往企圖用比率的變化來掩飾絕對數量的變化A的百分比比B高，說明A比B多好強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假設百分比小的基數較大，則實際值較大假設百分比大的基數較小，則實際值較小結論被推翻引出分析Lackingmorespecificinformationaboutbaseamount,itisimpossibletoassessthereliabilityofthesurvey’sresults.假設并比較基數Supposethebaseamountof_____is_______,thenevenif______,_______.假設百分比小的對象基數可能很大However,itisquitelikelythatthebaseamountof___ismerely,andevenif____,______.假設百分比大的對象基數可能很小Therefore,theargumentisstronglyweakened.Supposethebaseamountofthefundofeducationinstitutionsis100milliondollars,thenevenifthereismerelya3%increase,itis3milliondollars.However,itisquitelikelythatthebaseamountofthefundofenvironmentalandreligiousgroupsismerely10thousandand20thousand,andevenifthereisa30%&23%increase,itissimply3thousandand4.6thousand.Therefore,theargumentisstronglyweakened.請注意：此類錯誤只和無基數的百分比有關系，和其它數據對象無關。5.質疑權威S

False-AuthorityFallacy調查的權威性值得質疑,何人,何時,何地進行,是否真正權威?

Theargumentusestheword______,butitfailstoprovidesufficientevidencetojustifytheauthorityoftheresearchersconductedtheresearch/theaccuracyoftheresearch.EXERCISES244650請注意：此類錯誤只和表示權威的詞語有關系，和其它無關。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,最高等等來描述數量,這使得人們很難估計實際數量到底是多少.ExampleTheCumquatCafemadeamistakeinmovingtoanewlocation.Afteroneyearatthenewspot，itisdoingaboutthesamevolumeofbusinessasbefore，buttheownersoftheRoboWrenchplumbingsupplywholesaleoutletthattookoveritsoldlocationareapparentlydoingbetter：RoboWrenchisplanningtoopenastoreinaneighboringcity.Theword____inthestatementthat______istoovaguetobemeaningful.However,thearguerfailstoprovideasecondtermtoclarifytheblur.EXERCISE2388109二，因果關系類

(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.基本錯誤模型A----BConclusionExampleTheCumquatCafebeganadvertisingonourlocalradiostationthisyearandwasdelightedtoseeitsbusinessincreaseby10percentoverlastyear’stotals.Theirsuccessshowsyouhowyoucanuseradioadvertisingtomakeyourbusinessmoreprofitable.MODEL原因結果原因2原因3原因4復述原文的原因和結論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：此類錯誤只和因果關系有關（原因—結論），和其它無關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錯誤的邏輯關系上的而這個邏輯關系就是作者基于時間先后所錯誤得出的因果關系。因此，我們這里要駁斥這種關系！基本錯誤模型INCIDENT1INCIDENT2PASTPRESENTCAUSALThesequenceoftime

標志詞：afterthissincethenwhenagoExampleAfteropeningthenewswimmingpoolearlylastsummer,TakeHeartsawa12percentincreaseintheuseofthecenterbymembers.

（錯誤的因果關系）Therefore,inordertoincreasethenumberofourmembers,weshouldcontinuetoaddnewrecreationalfacilitiesinsubsequentyears:forexample,amultipurposegameroom,atenniscourt,andaminiaturegolfcourse.（作者的推斷）點出邏輯關系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，也包含有因果關系。但是這個錯誤中必需包含時間上的前后關系。3.因果倒置SThefallacyofconfusingthecauseandtheeffect經過調查：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------------------酒量大事實上，天生酒量就大，才能喝二斤。基本錯誤模型A---BCONCLUSIONB---AOfthosewhoresponded,themenwhoreportedthattheyengagedinvigorousoutdoorexercisenearlyeverydaylivedlongerthanthemenwhoreportedthattheyexercisedmildlyonlyonceortwiceaweek.Giventheclearlinkthatthisstudyestablishesbetweenlongevityandexercise,doctorsshouldnotrecommendmoderateexercisetotheirpatientsbutshouldinsteadencouragevigorousoutdoorexerciseonadailybasis.Thearguerassumesthat____causes_____.However,itislikelythatjustbecause_____,______.Thearguerassumesthatvigorousexercisescausetheirlongevity.However,itislikelythatjustbecauseofagoodphysicalcondition,theytakevigorousexercises.三，比較類比(evidence)AnalogyandComparison1.錯誤類比S2.同等謬誤1.錯誤類比S

ThefallacyoffaultyanalogyAndyandFurongSisterbothexcelatdancing.SinceFurongisawoman,itislikelythatAndyisawomantoo.基本錯誤模型對象A對象B交集CONCLUSIONExampleTheCumquatCafemadeamistakeinmovingtoanewlocation.Afteroneyearatthenewspot，itisdoingaboutthesamevolumeofbusinessasbefore，buttheownersoftheRoboWrenchplumbingsupplywholesaleoutletthattookoveritsoldlocationareapparentlydoingbetter：RoboWrenchisplanningtoopenastoreinaneighboringcity.Aretheysimilarenough?點出文中的類比關系Theargumentrestsonfaultyanalogybetween____and____.CumquatCafeRoboWrench點出類比關系中的同和異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，杜老師是應該還會得第一.基本錯誤模型假設事件發生的條件和背景不隨著時間和地點的變化而改變。

過去=將來A地=B地不同時間/不同地點-----產生同樣結果那有人會問:它和錯誤類比有什么區別？區別很簡單，請看以下陳述小明去年得了三好學生，因此今年他還會得莫非這里的共同點是，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.結尾Allthesefactorsmentionedabovecanservetoweakenthearguer’claim.四，改變范圍類（evidence）Changingscope1.整體推個體S2.偷換概念1.整體推個體SThegeneraldoesn’tequalaspecificfallacy根據統計和調查，全國的男同胞都會娶女人為妻。因此，杜老師也會娶女人。整體情況不等于個體情況，因為可能存在exception.MayorBrownwasrecentlyre-electedbyaclearmajorityof52percentofMonroetown‘svoters.Herre-election,however,doesnotshowthatmostpeopleinourtownfavoredMayorBrown’sproposalfortaxreductionoverthatofheropponent,Mr.Greene,whoproposedraisingtaxestoimproveeducation.Thisisclearlybecausevotersnationwidetendtore-electpeoplealreadyinoffice,regardlessofcandidates'proposals.提出文中的關系Theauthorunfairlyassumesthatthenationwidetendencyappliesspecificallyto_______TheauthorunfairlyassumesthatthenationwidetendencyappliesspecificallytoMonroetownresidents.指出和整體存在差異的可能性Lackingevidencethat個體reflectthisgeneraltendency,itisentirelypossiblethat與整體相反可能性./thetrendof_____mightbejusttheoppositeLackingevidencethatMonreotownresidents

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

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