批判性推理入门Critical Reasoning for beginners全笔记

Critical Reasoning for beginnersby Marianne Talbot OxfordLesson 1How 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) are being offered as reasons for believing the truth of the one.An argument isn't 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) Premises Conclusion (Function)[to prove---reasons] [suppose true]relationship among sentencese.g. It's Friday.Marianne always wears jeans on Friday.Therefore Marianne will wear jeans today.Play attention to suppressed premises（隐藏前提）.context——all sentences may be argument.implication（实质蕴涵）entailment（逻辑蕴涵）Distinguish arguments from(a) sets of sentences not related as arguments(1) aren't related at alle.g. The sea is salt.Sydney is in Australia.(2) related but not an argumente.g. Towards lunchtime clouds formed and the sky blackened. Then the storm broke.(b) sentences (assertions) 'if...then...'e.g. If 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）and rational relations（推理关系）A andB entailC doesn't mean A and B cause C.e.g. It's 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 explanation（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 don't exist.Only beliefs or sentences that express beliefs are true or false.Belief (e.g. concept)..............the concept 'chair' Language..................................the language 'c-h-a-i-r' Reality.......................................the object 'chair'Arguments can only be good or bad ,they can only be valid or invalid ,they can't 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 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 2Different sorts of argumentstwo basic types of arguments: deduction and inductionDeductive argument :the truth of their premises guarantees the truth of their conclusion.e.g. It's Friday.Marianne always wears jeans on Friday.Therefore Marianne will wear jeans today.If the premises are true, the conclusion would be true.'truth guaranteeing' 'truth preserving'Deduction is an 'either or' thing:a good deductive argument gives us conditional certainty.a bad one tells us nothing.Inductive arguments are such that the truth of their premises makes the conclusion more or less probable. (don't 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 necklace.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, therefore 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、Leibniz's Law 莱布尼兹律（相同者不可辨识）a is F, a=b, thereforeb is F.e.g. Jane is(predication) 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 'is's 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 is wrong.Therefore we shouldn't 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 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 arguments there are many different sub-types:1、arguments from analogy类比推理a is like b, a is F, thereforeb 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Causal 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. 飞马不存在。