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WhatisCri9calThinking?Chapter4

WhatisaSkep9c?

•  Ascien9ficskep9cisledbyevidence,notpersonalbeliefs

•  Triestoovercomebiasesandmispercep9onsandarewillingtobewrong

•  Iswillingtosay“Idon’tknow”ratherthanprofessanon-jus9fiedbelief

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WhatisaSkep9c?

•  Allbeliefsshouldbecon9ngentontheinforma9onwehaveaccessto

•  Skep9csfightfornuanceinbeliefbynotfeigningconvic9onwhenitisinappropriate

•  Skep9csarewillingtoembraceuncertainty,andassertwhenaconclusionisstronglyjus9fied

NotActualSkep9cs

•  Peoplesome9mesuse“skep9c”whentheyshouldusetheterms“cynic”or“denier”

•  Bothreferto“hyperskep9cs”whodoubtordenythescien9ficconsensusandengageinpseudoscien9ficthinking

DenialismExamples

•  HIVdoesn’tcauseAIDS

•  Globalwarmingisahoax

•  TheHolocaustwasn’treal

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TypesofSkep9cism

Scien&ficskep&cism–areopentonewideas,arewillingtochangeifpresentedwithevidence;donotacceptthewordofauthorityfiguresasevidence

TypesofSkep9cism

Pathologicalskep&cism–markedbyclosed-mindednessandcynicism;guiltyofthedisconfirma9onbias

MethodsMa[erMost

•  Scien9ficskep9csvaluehowwereachconclusionsoverwhattheconclusionis

•  Beingright(ifweare)istheendresultofaprocessofcri9calthinking

•  Focusingonconclusionsratherthanmethodscanresultindogma9smanddenial

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Op9malDecisions

•  Foranyonedecision,wecanbeoverwhelmediftryingtofactorinallpoten9alpiecesofinforma9ontomakethe“perfect”choice

•  Instead,wehavetounderstandthatweworkwithinboundedra.onality

BoundedRa9onality

•  Allourdecisionsareconstrainedbynumerousfactors– Timeavailabletothinkaboutaproblem–  Informa9onwehaveaccessto– Resourceshortages(moneyor9meforresearch)

•  Weneedtosa.sfice,ormakethebestdecisionwecanwithinourlimits

GotProblems?NeedResearch!

•  Anyproblemthatyouaretryingtosolveorques9onyouaretryingtoanswercanbearesearchac9vity

•  Researchinvolves– Gatheringinforma9on– Arrangingthatinforma9onintoausefulpackage– Usingthatinforma9ontoguideac9ons

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Cri9calThinking

•  Understandingthatweoeenmakeerrorsorshowbiaseswhenevalua9nginforma9on

AND

•  Developingandimplemen9ngbestprac9cesforgatheringandusinginforma9ontomakedecisionsaboutbeliefs

TheSpaceofReasons

•  Ifaseriousissueisatstake,youshouldbeabletogivereasonswhyyoubelieveonethingratherthansomethingelse

•  Conversely,youshouldbeenabledtoaskotherpeopleforthesame

•  Cri9calthinkingenablessoundreasons

TheSpaceofReasons

•  Ifanac9onordecisiontakenbysomeoneelseislikelytoaffectyou,itisreasonableto– Requireevidencethatthedecisionorac9onhasbeenthoughtthrough

– Foryoutobereassuredthatthedecisionwas•  Takencarefully•  Notmadeasaconsequenceofsomebiasorprejudice

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TheSpaceofReasons

•  Conversa9onisaseriesofongoingdebatesandresearch

•  Eachsidepresentstheirevidenceandreasoningforwhytheirbeliefisjus.fied

ArgumentandArgumenta9on

•  “Argument”doesn’thavemeananaggressiveoremo9onalba[le

•  Itcanbeapar9cularmethodologythatprovidesuswiththebestpossiblechanceofarrivingataconclusionthat– Bestfitstheevidence– Hasthemostadvantageousconsequences

ArgumentandArgumenta9on

•  Weoeendon’tevenrealizewhenwe’vemadeadecisionusingargumenta9on

•  What’sfordinner?

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Non-Arguments

•  Notallcommunica9onisargument– Expressingfeelings– Askingques9ons– Describingevents– Explana9ons

•  But,weneedargumentsassoonasapointofview,decisionorac9onneedstobejus.fied

GlobalDebates

•  Itisalmostcertainthatyouwillinteractwiththosewhohavedifferentbeliefs

•  Weneedresourcestodeterminewhatisworthbelievingwithoutthesafetynetofourpreconceivedhabits

GlobalDebates

•  Everyonehasapar9cularculturalbackground,whichcomeswithit’sownsetofblinders

•  So,youneedtoconsiderwhyyoumightbewrong,inordertofeeljus9fiedthatyouareactuallyright

•  Cri9calthinkingprovidesamethodforarrivingatworthwhilebeliefs

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Cri9calThinking

•  Rulesofthumbthatletusbecomeconsistentlybe[eratreachinggoodconclusions– Extraordinaryclaims– Falsifiability– Occam’srazororparsimony– Rulingoutrivalhypotheses– Recognizingfallacies– Separa9nginduc9onfromdeduc9on

ExtraordinaryClaims

•  “Awiseman...propor9onshisbelieftotheevidence.“

•  "Notes9monyissufficienttoestablishamiracle,unlessthetes9monybeofsuchakind,thatitsfalsehoodwouldbemoremiraculousthanthefactwhichitendeavorstoestablish.”

DavidHume,18thcenturyScokshphilosopher

ExtraordinaryClaims

•  Hume’swordsinspiredCarlSagantosay…

“Extraordinaryclaimsrequireextraordinaryevidence.”

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ExtraordinaryClaims

•  Agoodskep9cbelievessomethingonlytothedegreethatitissupportedbyevidence

•  Themorespectacularaclaimis,themoresolidtheevidenceforsuchaclaimmustbeinordertotakeitseriously

Falsifiability

•  Determiningtruthviatryingtoproveourbeliefsisinherentlyflawed

Falsifiability

•  Instead,weneedtodeterminetruthviates9ngsomethingtoseeifitisfalse

•  Ifaclaimisfalsifiableandsurvivesoura[emptstofalsifyit,wecanconsideritstrong

•  So,takeawaythes9cksfromthemaninTimesSquaresandseeiftheelephantsshowup

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Falsifica9on

•  Ifthereisnopossibilityofsomethingbefalsified,thenthereisnora.onalreasontobelieveit

•  Ifcanbebelievedforotherreasons(emo9onal,spiritual)butnotra9onalones

Occam’sRazor

•  Whenconsideringvariousexplana9onsforanyphenomena,selecttheonewiththefewestnumberofaddi9onalassump9onsorcomplica9ons

•  Principleofparsimony WilliamofOckham,14thcenturyEnglishfriar

RulingOutRivalHypotheses

•  Parsimonydoesnotguaranteeyouhaveselectedthecorrecthypothesis

•  But,yourunalowerriskoferrorifyourelyonassump9onsthatarenotthemselvesindoubtorunprovable

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Fallacies

•  Broadtermforaspecifictypeoferrorormistakeinreasoning

•  Conclusionsthatsomehasmadefallaciouslyaren’talwayswrong,buttheydon’thaveajus.fiedreasonforsomeonetobelievethem

SpecificFallacies

•  Almosttoonumeroustomen9on!– ThouShaltNotCommitLogicalFallacies

EngagingwithFallacies

•  Althoughentertaining,justpoin9ngoutwhatkindoffallacysomeoneismakingdoesli[letospreadcri9calthinking

•  Instead,beingabletodemonstratewhyaperson’s(oryourown!)reasoningisflawedisthekey– Thefallacyfallacy

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Induc9onvs

Inferenceaboutaruleorpa[ernbyreferencetospecificobserva9ons

Oeenbroadinscope

Predic9veabilitydependsonnumberandqualityofone’sobserva9ons

Deduc9on

Movesfromgeneralrulestospecificclaims

Modestinscope,withconclusionsgenerallynarrowerthanpremises

Conclusionsareoeenquitereliable

Logic&TruthPreserva9on

•  Trueevidenceresultsintrueconclusions,butonlyifyourreasoningiserror-free

•  Logicalone,though,doesnotguaranteetruth

•  Forexample…

1.   Grassisred.2.   Allredthingsarepoisonous.3.   Therefore,grassispoisonous.

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Logic&TruthPreserva9on

•  Logiccanbevalid,andyets9llremovedfromreality

•  Certainty(viathestructureofanargument)isdifferentfromconfidence(viatheevidenceforanargument)

Conclusions

•  Beingagoodcri9calthinkerishardwork

•  Weshouldfocusonwhetherornotabeliefisjus.fied,ratherthanbeingcertainitistrue

•  Doestheavailableevidence,whenevaluatedfairly,makeacertainbeliefmorelikelytobetruethananycompe9ngbeliefs?