完整word批判性推理入门Critical Reasoning for beginners全笔记.docx
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完整word批判性推理入门CriticalReasoningforbeginners全笔记
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,youd