批判性推理基础学习CriticalReasoningforbeginners全记录文本.docx

批判性推理基础学习CriticalReasoningforbeginners全记录文本.docx

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批判性推理基础学习CriticalReasoningforbeginners全记录文本

CriticalReasoningforbeginners

byMarianneTalbotOxford

Lesson1HowtorecognizeargumentsandWhatisthenatureofarguments

Argumentsareasetofsentencessuchthatoneofthem（theconclusion）isbeingsaidtobetrue,andtheother（s）（thepremises）arebeingofferedasreasonsforbelievingthetruthoftheone.

Anargumentisn'tasetofcontradictions.

Partofthepointofanargumentistomoveusonfromwherewearetosomewhereabitfurther.

Argumentsleadtodeeperthoughts.（fromwherewearetowherewewant）

AnArgument:

（oneormore）PremisesConclusion（Function）

[toprove---reasons][supposetrue]

relationshipamongsentences

e.g.It'sFriday.

MariannealwayswearsjeansonFriday.

ThereforeMariannewillwearjeanstoday.

Playattentiontosuppressedpremises（隐藏前提）.

context——allsentencesmaybeargument.

implication（实质蕴涵）

entailment（逻辑蕴涵）

Distinguishargumentsfrom

（a）setsofsentencesnotrelatedasarguments

（1）aren'trelatedatall

e.g.Theseaissalt.

SydneyisinAustralia.

（2）relatedbutnotanargument

e.g.Towardslunchtimecloudsformedandtheskyblackened.Thenthestormbroke.

（b）sentences（assertions）'if...then...'

e.g.Ifitissnowing,themailwillbelate.

（implicationnotentailment）

Anargumentisasetofsentences,oneofwhichisbeingasserted.

Anassertionisasinglesentence（possiblycomplex）,thatisbeingexpressedinassertivemode.

'because'maybecausalorrational.

reasonandcause

causalrelations（因果关系）andrationalrelations（推理关系）

AandBentailCdoesn'tmeanAandBcauseC.

e.g.It'sFriday.（A）

MariannealwayswearsjeansonFriday.（B）

ThereforeMariannewillwearjeanstoday.（C）

explanation:

（1）causalexplanation（因果性解释）:

e.g.Pawlfelldownbecausehewantedtoamusechildren.

（2）rationalexplanation（推理性解释）:

e.g.PawlfelldownbecauseJellypushedhim.

Factsarewhatmakessentencestrueorfalse.Theyarenottrueorfalse,theyjustexistordon'texist.

Onlybeliefsorsentencesthatexpressbeliefsaretrueorfalse.

Belief（e.g.concept）..............theconcept'chair'

Language..................................thelanguage'c-h-a-i-r'

Reality.......................................theobject'chair'

Argumentscanonlybegoodorbad,theycanonlybevalidorinvalid,theycan'tbetrueorfalsebecausetheonlythingthatcanbetrueorfalseisbeliefsorthesentencesthatexpressbeliefs.

Agoodargumentisoneinwhich:

（1）theconclusionmustfollowthepremises

（2）thepremisesmustallbetrue.

Theconclusionmustbetrue.（truthpreserving）

逻辑学并不关心前提正确与否，而只关心前提与结论的关系。

Lesson2Differentsortsofarguments

twobasictypesofarguments:

deductionandinduction

Deductiveargument:

thetruthoftheirpremisesguaranteesthetruthoftheirconclusion.

e.g.It'sFriday.

MariannealwayswearsjeansonFriday.

ThereforeMariannewillwearjeanstoday.

Ifthepremisesaretrue,theconclusionwouldbetrue.

'truthguaranteeing''truthpreserving'

Deductionisan'eitheror'thing:

agooddeductiveargumentgivesusconditionalcertainty.

abadonetellsusnothing.

Inductiveargumentsaresuchthatthetruthoftheirpremisesmakestheconclusionmoreorlessprobable.（don'tguarantee）

Inductiveargumentscanbeeitherweakorstrong.

[strong]:

Thesunhasriseneverydayinthehistoryoftheuniverse.Thereforethesunwillrisetomorrow.

[weak]:

EverytimeImetMary,sheworeanecklace.

ThereforethenexttimeImeether,shewillwearanecklace.

逻辑学是中立性的，逻辑的形式可以适用于任何的内容。

Logiciansstudydeductionbystudyingvalidargumentsforms

Argumentsthatarevalidisinvirtueoftheirformsasopposedtotheircontents.

theformsofdeduction:

1、ModusPonens肯定前件取拒式

IfPthenQ,P,thereforeQ.（P,Qsentences）

wrong:

IfPthenQ,Q,thereforeP.

（Affirmingconsequent肯定后件式）

2、Modustollens否定后件式

IfPthenQ,not-Q,thereforenot-P.

3、Disjunctivesyllogism选言三段论

PorQ,not-P,thereforeQ.

（P或Q成立，P不成立，因此Q成立）

4、Leibniz'sLaw莱布尼兹律（相同者不可辨识）

aisF,a=b,thereforebisF.

e.g.Janeis（predication）tall.

Janeis（identity）thebankmanager.

Thereforethebankmanageris（predication）tall.

Note:

'is'canserveasapredication（论断）oridentity（同等）.

The'is'saboveserveaspredications.

Andthe'='aboveservesasidentity.

5、Syllogism三段论

allFsareG.

aisanF.

ThereforeaisaG.

6、DeonticLogic道义逻辑

e.g.Lyingiswrong.

Thereforeweshouldn'tlie.

7、ModalLogic模态逻辑

（alogicaboutnecessityandpossibility）

e.g.Itisnecessarilythecasethattherearenosquarecircles.

Thereforeitisnotpossiblethattherearesquarecircles.

8、TemporalLogic时序逻辑（时态逻辑）

e.g.Itisrainingtoday.

Thereforetomorrowitwillhavebeenrainingyesterday.

Inductivearguments

Allinductiveargumentsrelyontheassumptionoftheuniformityofnature（theideathatthefuturewillbelikethepast）

哲学中的一个基本问题是，我们对未来的假设，会不会和过去的经验相一致？

Uniformity一致性，uniformityofnature（DavidHume）自然界是否具有一致性？

Withinthecategoryofinductiveargumentstherearemanydifferentsub-types:

1、argumentsfromanalogy类比推理

aislikeb,aisF,thereforebisF.

（小写字母：

particularthing特定的事物

大写字母：

性质或句子）

2、argumentsfromauthority诉诸权威的论证

e.g.Einsteinisabrilliantphysicist.

Einsteinsaysrelativismistrue.

Thereforerelativismistrue.

Causalarguments因果论证

Causalargumentscanbedeductiveorinductive,dependingonwhetherwearearguingfromacausalclaimortoacausalclaim.

deductive:

AscauseBs.

TherewasanA.

ThereforetherewillhavebeenaB.

inductive:

EveryobservedAhasbeenfollowedbyaB.

ThereforeAscauseBs.

negativeexistential否定存在判断句

e.g.飞马不存在。

Wecanknowthat

argumentsthataredeductivelyvalid

——invirtueoftheirforms

——invirtueoftheircontent

e.g.DeonticLogic,TemporalLogic

argumentsthatareinductivelyvalid

——theuniformityofnature

Lesson3'logic-book-style'逻辑书

thepoint:

（a）itenablesustoaddsuppressedpremises隐含前提

（b）itenablesustoeliminatecrossreferences,irrelevanciesandinconsistentterms排除交叉引用、无关和不一致词语

（c）itmakesiteasiertoevaluatearguments.

Asetofstepsforanalyzingarguments:

1.identifytheconclusionoftheargument

Lookfortheargumentindicators（so,therefore,then,if...then...,accordingly,hence,since,for,because,fromwhichweseethat,itfollowsthat,whichestablishesthat...）

2.identifyeachofthepremises

3.addsuppressedpremises

4.removeirrelevancies

5.removeinconsistentterms

6.removecross-references

Example1:

Socialismdidnotprovidetheincentivesneedforaprosperouseconomy.Thereforesocialismwasdoomedtofailure.

Premise1:

Incentivesareneededforaprosperouseconomy.

Premise2:

Socialismdidnotprovideincentives.

Conclusion:

Socialismwasdoomedtofailure.

Premisesandconclusionmustbesentences.

P,unlessQ.

IfQ,thenR.P

ButnotR.

Example2:

Sincemanynewlyemergingnationsdonothavethecapitalresourcesnecessaryforsustainedgrowth,theywillcontinuetoneedhelpfromindustrialnations.

Premise1:

Manynewlyemergingnationsdonothavecapitalresources

Premise2:

Capitalresourcesarenecessaryforsustainedgrowth.

Premise3:

Ifanewlyemergingnationistosustainitsgrowth,anditdoesnothavecapitalresources,itwillneedhelpfromindustrialnations.

Conclusion:

Manynewlyemergingnationswillneedhelpfromindustrialnations.

Example3:

Wellperhapsshedidn'twantyoutoticklehertummy,orshedidn'trealizethatwaswhatyouweregoingtodo.Ifshedidn'trealize,thenyouobviouslywentaboutitinthewrongway.Inthatcaseyoudeservedtogetscratchedunlessyoureadythoughtshewassuchaperceptivecatthatshe'dunderstand'woof-woof'meant'rollover'.Ifyouthoughtthatyou'reanidiot.Butyou'renotanidiotyou'rejusttwisted.Soifthepoorthingdidwantyoutoticklehertummyyoudeservetogetscratched.

1Identifypremisesandconclusion

Premise1:

Wellperhapsshedidn'twantyoutoticklehertummy,orshedidn'trealizethatwaswhatyouweregoingtodo

Premise2:

Ifshedidn'trealize,thenyouobviouslywentaboutitinthewrongway.

Premise3:

Inthatcaseyoudeservedtogetscratchedunlessyoureadythoughtshewassuchaperceptivecatthatshe'dunderstand'woof-woof'meant'rollover'.

Premise4:

Ifyouthoughtthat,you'reanidiot.Butyou'renotanidiotyou'rejusttwisted.

Conclusion:

Soifthepoorthingdidwantyoutoticklehertummyyoudeservetogetscratched.

2Addsuppressedpremises

（None）

3Removeirrelevancies

draft:

Premise1:

Wellperhapsshedidn'twantyoutoticklehertummy,orshedidn'trealizethatwaswhatyouweregoingtodo

Premise2:

Ifshedidn'trealize,thenyouobviouslywentaboutitinthewrongway.

Premise3:

Inthatcaseyoudeservedtogetscratchedunlessyoureadythoughtshewassuchaperceptivecatthatshe'dunderstand'woof-woof'meant'rollover'.

Premise4:

Ifyouthoughtthat,you'reanidiot.Butyou'renotanidiotyou'rejusttwisted.

Conclusion:

Soifthepoorthingdidwantyoutoticklehertummyyoudeservetogetscratched.

Premise1:

Shedidn'twantyoutotickleher,orshedidn'trealizethatwaswhatyouweregoingtodo

Premise2:

Ifshedidn'trealize,thenyouwentaboutitinthewrongway.

Premise3:

Inthatcaseyoudeservedtogetscratched.

Conclusion:

Soifthepoorthingdidwantyoutotickleheryoudeservetogetscratched.

4Removeinconsistenttermsandcrossreferences（simplify）

Premise1:

Shedidn'twantyoutotickleher,orshedidn'trealizeyouweregoingtotickleher

Premise2:

Ifshedidn'trealizeyouweregoingtotickleher,thenyouweregoingtotickleherinthewrongway.

Premise3:

Ifyouweregoingtotickleherinthewrongway,youdeservedto