Critical Reasoning for beginners
by Marianne Talbot Oxford
Lesson 1 How to recognize arguments and What is the nature of arguments
Arguments are a t of ntences such that one of them (the conclusion) is being said to be true, and the other(s) (the premis) are being offered as reasons for believing the truth of the one.
An argument isn't a t of contradictions.
Part of the point of an argument is to move us on from where we are to somewhere a bit further.
程度英文Arguments lead to deeper thoughts. (from where we are to where we want)
An Argument:
(one or more) Premis Conclusion (Function)
[to prove---reasons] [suppo true]
relationship among ntences
e.g. It's Friday.
Marianne always wears jeans on Friday.
Therefore Marianne will wear jeans today.
Play attention to suppresd premis（隐藏前提）.
context——all ntences may be argument.
implication（实质蕴涵）
entailment（逻辑蕴涵）
Distinguish arguments from
(a) ts of ntences not related as arguments
(1) aren't related at all
e.g. The a is salt.
Sydney is in Australia.vested
(2) related but not an argument
e.g. Towards lunchtime clouds formed and the sky blackened. Then the storm broke.
(b) ntences (asrtions) 'if...'
e.g. If it is snowing, the mail will be late.
(implication not entailment)
shirt什么意思An argument is a t of ntences, one of which is being asrted.
An asrtion is a single ntence (possibly complex) ,that is being expresd in asrtive mode.
'becau' may be causal or rational.
reason and cau
causal relations（因果关系） and rational relations（推理关系）
A and B entail C doesn't mean A and B cau 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 becau he wanted to amu children.
(2) rational explanation（推理性解释）:
e.g. Pawl fell down becau Jelly pushed him.
Facts are what makes ntences true or fal. They are not true or fal, they just exist or don't exist.
Only beliefs or ntences that express beliefs are true or fal.
Belief (e.g. concept)..............the concept 'chair'
he language 'c-h-a-i-r'
he object 'chair'
Arguments can only be good or bad ,they can only be valid or invalid ,they can't be true or fal becau the only thing that can be true or fal is beliefs or the ntences that express beliefs.
A good argument is one in which:
(1)the conclusion must follow the premis
outside怎么读英语
(2)the premis must all be true.
The conclusion must be true. (truth prerving)
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 arguments
怎么化眼妆two basic types of arguments: deduction and induction
Deductive argument :上海游戏培训
the truth of their premis 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 premis are true, the conclusion would be true.
'truth guaranteeing' 'truth prerving'
Deduction is an 'either or' thing: va国际教育
a good deductive argument gives us conditional certainty.d day
a bad one tells us nothing.
Inductive arguments are such that the truth of their premis makes the conclusion more or less probable. (don't guarantee)
Inductive arguments can be either weak or strong.
[strong]:The sun has rin every day in the history of the univer. Therefore the sun will ri 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 forms
Arguments that are valid is in virtue of their forms as oppod 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 ntences)
wrong: If P then Q, Q, therefore P.
(Affirming conquent肯定后件式)
2、Modus tollens否定后件式
If P then Q, not-Q, therefore not-P.
advertirs3、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, therefore b is F.
e.g. Jane is(predication) tall.
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