1、批判性推理基础学习CriticalReasoningforbeginners全记录文本Critical Reasoning for beginnersby Marianne Talbot OxfordLesson 1 How to recognize arguments and What is the nature of argumentsArguments are a set of sentences such that one of them (the conclusion) is being said to be true, and the other(s) (the premises)
2、 are being offered as reasons for believing the truth of the one.An argument isnt a set of contradictions. Part of the point of an argument is to move us on from where we are to somewhere a bit further. Arguments lead to deeper thoughts. (from where we are to where we want)An Argument: (one or more)
3、 Premises Conclusion (Function) to prove-reasons suppose truerelationship among sentencese.g. Its Friday. Marianne always wears jeans on Friday. Therefore Marianne will wear jeans today.Play attention to suppressed premises（隐藏前提）.contextall sentences may be argument.implication（实质蕴涵）entailment（逻辑蕴涵）
4、Distinguish arguments from(a) sets of sentences not related as arguments (1) arent related at all e.g. The sea is salt. Sydney is in Australia. (2) related but not an argument e.g. Towards lunchtime clouds formed and the sky blackened. Then the storm broke.(b) sentences (assertions) if.then.e.g. If
5、it is snowing, the mail will be late.(implication not entailment) An argument is a set of sentences, one of which is being asserted.An assertion is a single sentence (possibly complex) ,that is being expressed in assertive mode.because may be causal or rational. reason and causecausal relations（因果关系
6、） and rational relations（推理关系）A and B entail C doesnt mean A and B cause C.e.g. Its Friday. (A) Marianne always wears jeans on Friday. (B) Therefore Marianne will wear jeans today. (C)explanation:(1) causal explanation（因果性解释）:e.g. Pawl fell down because he wanted to amuse children.(2) rational expla
7、nation（推理性解释）:e.g. Pawl fell down because Jelly pushed him.Facts are what makes sentences true or false. They are not true or false, they just exist or dont exist.Only beliefs or sentences that express beliefs are true or false.Belief (e.g. concept).the concept chairLanguage.the language c-h-a-i-rRe
8、ality.the object chairArguments can only be good or bad ,they can only be valid or invalid ,they cant be true or false because the only thing that can be true or false is beliefs or the sentences that express beliefs. A good argument is one in which: (1)the conclusion must follow the premises(2)the
9、premises must all be true.The conclusion must be true. (truth preserving)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。Lesson 2 Different sorts of argumentstwo basic types of arguments: deduction and inductionDeductive argument :the truth of their premises guarantees the truth of their conclusion.e.g. Its Friday. Mari
10、anne always wears jeans on Friday. Therefore Marianne will wear jeans today. If the premises are true, the conclusion would be true.truth guaranteeing truth preservingDeduction is an either or thing: a good deductive argument gives us conditional certainty.a bad one tells us nothing.Inductive argume
11、nts are such that the truth of their premises makes the conclusion more or less probable. (dont guarantee)Inductive arguments can be either weak or strong.strong:The sun has risen every day in the history of the universe. Therefore the sun will rise tomorrow.weak:Every time I met Mary, she wore a ne
12、cklace.Therefore the next time I meet her, she will wear a necklace.逻辑学是中立性的，逻辑的形式可以适用于任何的内容。Logicians study deduction by studying valid arguments formsArguments that are valid is in virtue of their forms as opposed to their contents.the forms of deduction:1、Modus Ponens肯定前件取拒式If P then Q, P, theref
13、ore Q. (P,Q sentences)wrong: If P then Q, Q, therefore P. (Affirming consequent肯定后件式)2、Modus tollens否定后件式If P then Q, not-Q, therefore not-P.3、Disjunctive syllogism选言三段论P or Q, not-P, therefore Q.（P或Q成立，P不成立，因此Q成立）4、Leibnizs Law 莱布尼兹律（相同者不可辨识）a is F, a=b, therefore b is F. e.g. Jane is(predication)
14、tall.Jane is(identity) the bank manager.Therefore the bank manager is(predication) tall.Note:is can serve as a predication（论断） or identity（同等）.The iss above serve as predications.And the = above serves as identity.5、Syllogism三段论all Fs are G.a is an F.Therefore a is a G.6、Deontic Logic道义逻辑e.g. Lying
15、is wrong.Therefore we shouldnt lie.7、Modal Logic模态逻辑（a logic about necessity and possibility)e.g. It is necessarily the case that there are no square circles.Therefore it is not possible that there are square circles.8、Temporal Logic时序逻辑（时态逻辑）e.g. It is raining today.Therefore tomorrow it will have
16、been raining yesterday.Inductive argumentsAll inductive arguments rely on the assumption of the uniformity of nature (the idea that the future will be like the past)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 ，uniformity of nature (David Hume)自然界是否具有一致性？Within the category of inductive argumen
17、ts there are many different sub-types:1、arguments from analogy类比推理a is like b, a is F, therefore b is F.（小写字母：particular thing特定的事物大写字母：性质或句子）2、arguments from authority诉诸权威的论证e.g. Einstein is a brilliant physicist.Einstein says relativism is true.Therefore relativism is true.Causal arguments因果论证Caus
18、al arguments can be deductive or inductive, depending on whether we are arguing from a causal claim or to a causal claim.deductive: As cause Bs.There was an A.Therefore there will have been a B.inductive: Every observed A has been followed by a B.Therefore As cause Bs.negative existential否定存在判断句e.g.
19、 飞马不存在。We can know thatarguments that are deductively validin virtue of their formsin virtue of their content e.g. Deontic Logic ,Temporal Logicarguments that are inductively validthe uniformity of natureLesson 3 logic-book-style逻辑书the point: (a)it enables us to add suppressed premises隐含前提(b)it enab
20、les us to eliminate cross references, irrelevancies and inconsistent terms排除交叉引用、无关和不一致词语(c)it makes it easier to evaluate arguments.A set of steps for analyzing arguments:1. identify the conclusion of the argument Look for the argument indicators (so, therefore, then, if.then., accordingly, hence,
21、since, for, because, from which we see that, it follows that, which establishes that.)2. identify each of the premises3. add suppressed premises4. remove irrelevancies5. remove inconsistent terms6. remove cross-referencesExample 1: Socialism did not provide the incentives need for a prosperous econo
22、my. Therefore socialism was doomed to failure.Premise 1: Incentives are needed for a prosperous economy.Premise 2: Socialism did not provide incentives.Conclusion: Socialism was doomed to failure.Premises and conclusion must be sentences.P, unless Q.If Q, then R. PBut not R.Example 2:Since many newl
23、y emerging nations do not have the capital resources necessary for sustained growth, they will continue to need help from industrial nations.Premise 1: Many newly emerging nations do not have capital resourcesPremise 2: Capital resources are necessary for sustained growth.Premise 3: If a newly emerg
24、ing nation is to sustain its growth, and it does not have capital resources, it will need help from industrial nations.Conclusion: Many newly emerging nations will need help from industrial nations.Example 3:Well perhaps she didnt want you to tickle her tummy, or she didnt realize that was what you
25、were going to do. If she didnt realize , then you obviously went about it in the wrong way. In that case you deserved to get scratched unless you ready thought she was such a perceptive cat that shed understand woof-woof meant roll over . If you thought that youre an idiot. But youre not an idiot yo
26、ure just twisted. So if the poor thing did want you to tickle her tummy you deserve to get scratched.1 Identify premises and conclusionPremise1: Well perhaps she didnt want you to tickle her tummy, or she didnt realize that was what you were going to doPremise2: If she didnt realize , then you obvio
27、usly went about it in the wrong way.Premise3: In that case you deserved to get scratched unless you ready thought she was such a perceptive cat that shed understand woof-woof meant roll over .Premise4: If you thought that , youre an idiot. But youre not an idiot youre just twisted.Conclusion: So if
28、the poor thing did want you to tickle her tummy you deserve to get scratched.2 Add suppressed premises(None)3 Remove irrelevanciesdraft:Premise1: Well perhaps she didnt want you to tickle her tummy, or she didnt realize that was what you were going to doPremise2: If she didnt realize , then you obvi
29、ously went about it in the wrong way.Premise3: In that case you deserved to get scratched unless you ready thought she was such a perceptive cat that shed understand woof-woof meant roll over .Premise4: If you thought that , youre an idiot. But youre not an idiot youre just twisted.Conclusion: So if
30、 the poor thing did want you to tickle her tummy you deserve to get scratched.Premise1: She didnt want you to tickle her, or she didnt realize that was what you were going to doPremise2: If she didnt realize , then you went about it in the wrong way.Premise3: In that case you deserved to get scratch
31、ed.Conclusion: So if the poor thing did want you to tickle her you deserve to get scratched.4 Remove inconsistent terms and cross references (simplify)Premise1: She didnt want you to tickle her, or she didnt realize you were going to tickle herPremise2: If she didnt realize you were going to tickle her , then you were going to tickle her in the wrong way.Premise3: If you were going to tickle her in the wrong way, you deserved to
