HTCTLesson89 [Compatibility Mode]

Argument ErrorsArgument Errors

Critical thinking as an across the curriculum course

www.themegallery.com

Contents

Introduction1

Structural Fallacies2

��Structural Fallacies2

Content Fallacies33

Argument Refutation4


1. Premise

2. Premise

3. Premise

Elements of argument

factual errors

3. Premise

4. ConclusionInferencelogical errors

(structure/formal and content/informal)

factual errors


Types of Fallacies

�Structural Fallacies� logical errors that

cause the invalidity of the argument

�Content Fallacies� logical and factual

errors that weaken the inductive strength or cause the unsoundness of the unsoundness of the argument

� dubious and clearly false premises


Ex: structural fallacy/ formal logical fallacy

invalid


�"It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife." (Jane

Ex: content fallacy/ informal logical fallacy

in want of a wife." (Jane

Austen wrote this in her

novel Pride and Prejudice)�Alleged certainty: dubious

premise

http://www.media-awareness.ca/english/resources/educational/handouts/online_hate/logical_fallacies_handout.cfm

invalid weak argument


1. All kangaroos have two heads.

2. All bats are kangaroos.

valid, but unsound

Ex: content fallacy/ factual fallacy

3. All bats have two heads.


Contents

Introduction1


�� Structural Fallacies2

Content Fallacies33


��


If the dog barks, then I will wake up.

I didn’t wake up.

So the dog didn’t bark.

If the dog barks, then I will wake up.If the dog barks, then I will wake up.

I woke up.

So the dog barked.

If the dog barks, then I will wake up.

The dog didn’t bark.

So I didn’t wake up.


All beagles are dogs.

All dogs have bark.

So all beagles bark.

Some students at HULIS are Chinese.Some students at HULIS are Chinese.

Some Chinese people are enjoying their holidays in the North Pole.

So some students at HULIS are enjoying their holidays in the North Pole.


All dogs bark.

No professor is a dog.

So no professor barks.

All dogs bark.

No professor barks.

No professor is a dog.No professor is a dog.

Most dogs bark.

Fido is a dog.

Fido barks.

Most dogs bark.

Fido barks.

Fido is a dog.


Almost all dogs like peanut butter.

Almost all things that like peanut butter don’t bark.

So almost all dogs don’t bark.


Structural Fallacies

• If you have Gucci bags, you’ll look cool.

• If you don’t have Gucci

http://www.vnexpress.net/Vietnam/Kinh-doanh/2007/10/3B9FB08B/

have Gucci bags, you won’t look cool.

•You may still look cool, probably not like this




A: I can’t stand Siamese cats. Ugh. They have those strange blue eyes.

B: Mary Ellen has a kitten with blue eyes. I didn’t


with blue eyes. I didn’t know its was Siamese.

Siamese cats have strange blue eyes.

Ellen’s kitten has blue eyes.Ellen’s kitten is Siamese.


Contents

Introduction1


��


Content Fallacies33


��


Content Fallacies

�Fallacies of Presumption�Fallacies of Relevance�Fallacies of Ambiguity


Fallacies of presumption

�Arguments that commit fallacies of presumption contain false premises or lack premises, and so fail to establish their conclusion.



�"You are either with us or against us. You have refused to join our cause, therefore you must be working against our cause.”

�False dilemma = there are not only 2 False dilemma = there are not only 2 choices (false premise)

http://onegoodmove.org/fallacy/ig.htm


� Residents of this state should vote to elect Kravitz as state governor in the upcoming election. During Kravitz’s final term as a state senator, she was a member of a special legislative committee that explored ways the state can reduce its escalating


committee that explored ways the state can reduce its escalating rate of violent crime. Elect Kravitz for governor, and our cities’ streets will be safer than ever.

� Hasty generalization: Assuming that all things remain unchanged over time (false premise)


� At the local Viewer Choice video store, the number of available movies in VHS-tape format remains about the same as three years ago, even though the number of available movies on DVD has increased tenfold over the past three


increased tenfold over the past three years. People who predict the impending obsolescence of the VHS format are mistaken, since demand for VHS movie rentals today clearly remains just as strong as ever.

� Hasty generalization: What’s true for a member is true for the whole group (false premise)



- Mom: For a marriage to work, people have to have a lot in common

- Daughter: Wrong! I know a lot of miserable marriages where the people had a lot in common.

People have a lot in common

The marriage will work.

People have a lot in common

The marriage will be miserable.

misunderstanding between mother and daughter; mother only mentions a necessary condition, but daughter mistakes it for that her mother thinks that it’s sufficient.

Necessary and Sufficient Conditions: Mistaking a necessary condition for a sufficient condition (dubious premise)


Necessary and sufficient Conditions

�(National Public Radio)� Interviewer: So, will we continue to see home

schooling in America?� Interviewee: As long as there are parents who � Interviewee: As long as there are parents who

love their kids and are willing to work hard, yes.

� That parents love their kids and are will to work hard is sufficient for home schooling in America.



- Maria: Professor, professor, why wouldn’t you answer my question in class?- Professor Zzzyyxx: Questions in my class I do not allow. If one student I am allowing to ask a question, then others I must allow. And then I question, then others I must allow. And then I will have lots and lots of questions to answer. And time I won’t have for my lecture.



If a student is allowed to ask question.

then all students are allowed to ask questions.

then all students will ask questions.

hidden premise: all students are equal

(if you add a premise here, U’ll change the context)??? insufficient to conclude that

(if you add a premise here, U’ll change the context)??? insufficient to conclude that

then the questions will be answered.

then I will have no time for my lecture.

� an example the fallacy of slippery slope (insufficient premises leading to false premises)

hidden premise: the time I spend answering all the questions will be at least equal to all the time I have.

??? insufficient to conclude that


- Don’t go out with a football player.- Why not?- You’re crazy about football players, and if

you go out with one, you’re sure to sleep with him

- So?- Then you’ll get pregnant. And you’ll marry


- Then you’ll get pregnant. And you’ll marry the guy. But those guys are jerks. You’ll end up cooking and cleaning for him while he and his buddies watch football on TV. In twenty years you’ll have five kids, no life and lots of regrets

- Gosh, I guess you’re right. I’ll go out with a basketball player instead


�Ông Đáng cũng khẳng định, mắm tôm chính là nguyên nhân đầu tiên gây bệnh tả trong vụ dịch vừa qua. Cục An toàn vệ sinh


qua. Cục An toàn vệ sinh thực phẩm đã điều tra 61 trường hợp mắc tả đầu tiên và nhận thấy, tất cả họ đều đã ăn mắm tôm.

�Post-hoc fallacy: “after this therefore because of this”: false premise


�Tại TP HCM, Khoa cấp cứu của các bệnh viện Chợ Rẫy, Trưng Vương, Nhân dân Gia Định,


Nhân dân Gia Định, Nhân dân, số ca nhập viện bị chấn thương sọ não do tai nạn giao thông giảm gần 50%, so với trước khi thực hiện đội mũ bảo hiểm.

http://www.vnexpress.net/Vietnam/Xa-hoi/2007/12/3B9FD676/


Fallacies of relevance

�the considerations that they offer in support of their conclusion are irrelevant to determining whether that conclusion is true � personal attack� irrelevant appeals� weak analogy


�I hear that Brigitte Bardot is campaigning for animals rights. But she’s the one who used to do advertisements for fur coats.


coats. �personal attack


The Presidential IQ Report

WASHINGTON --In a published report, the Lovenstein Institute of Scranton, Pennsylvania has detailed 147 Franklin D. Roosevelt (D)132 Harry Truman (D)122 Dwight D. Eisenhower (R)174 John F. Kennedy (D)174 John F. Kennedy (D)126 Lyndon B. Johnson (D)155 Richard M. Nixon (R)121 Gerald R. Ford (R)176 James E. Carter (D)105 Ronald W. Reagan (R)98 George H. W. Bush (R)182 William J. Clinton (D)91 George W. Bush (R)

http://lovenstein.org/



� Tôi cũng không hoàn toàn đồng tình với quan điểm là việc quan hệ trước hôn nhân là hoàn toàn hợp tự nhiên nếu tình yêu đủ chín. Vội vàng gì nhỉ? Tại sao các bạn trẻ không đợi thêm thời gian xây dựng tình cảm được lớn dần, lớn dần đơm hoa, kết được lớn dần, lớn dần đơm hoa, kết trái bằng một cuộc hôn nhân, đem lại hạnh phúc cho cả hai họ, lại hợp với thuần phong mỹ tục của người Việt.

� Appeal to traditions

http://www.vnexpress.net/Vietnam/Ban-doc-viet/Tam-su/2007/12/3B9FD84A/


�Nếu không đội mũ bảo hiểm, bạn sẽ thấy mình lạc lõng

�Appeal to popularity


Don’t be the last to buy…



�Appeal to Novelty


�Do you believe in God?

�No, I don’t like the thought that I’m


thought that I’m not in control.

�Appeal to consequences


�"During her 17 years as a professor of botany, Professor Thomas has proved herself to be well worth her annual salary of $50,000. Her classes are among the largest at the university, demonstrating her popularity among students. Moreover, the money she has brought to the


Moreover, the money she has brought to the university in research grants has exceeded her salary in each of the last two years. Therefore, in consideration of Professor Thomas' demonstrated teaching and research abilities, we recommend that she receive a $10,000 raise and a promotion to Department Chairperson; without such a raise and promotion, we fear that Professor Thomas will leave Elm City University for another college."


Wherever there's a pool there's always a flirtwherever there's school there'll always be homeworkwherever there's a beat there's always a drumwherever there’s fun there's always coca cola

doo doo doo doo doo doo doo doo doo dooo. doo doo doo doo doo always coca cola

Fallacies of Relevance

doo doo doo always coca colaThe stars will always shine, the birds will always singAs long as there's thirst, there's always the real thingCoca-cola is always the oneWherever there is fun there's always Coca-cola

Weak analogy


Fallacies of ambiguity

�Fallacies of ambiguity appear to support their conclusions only due to their imprecise use of language.

�Once terms are clarified, fallacies of Once terms are clarified, fallacies of ambiguity are exposed.


Contents

Introduction1


��


Content Fallacies33


��


1. Premise

2. Premise

3. Premise

Elements of argument

factual errors

3. Premise

4. ConclusionInferencelogical errors

(structure/formal and content/informal)

factual errors

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Argument by Jennifer

� Premise 1: In a debate debaters argue as hard as they can while in a deliberation it is easy for them to give up their side earlier than they should.

� Premise 2: The debating style is used in crucial argument.

� Premise 3: The debating style may let people get hurt � Premise 3: The debating style may let people get hurt but that does not have a considerable effect on the effectiveness of the style.

� Conclusion: A debate is better than a deliberation in getting us to the truth.

� Evaluation: Premise 2: appeal to popularity; Premise 1 & 3: no evidence to support these premises.

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Argument by Mark

�Premise 1: The pressure to save face or to win distracts debaters from the truth.

�Premise 2: Getting at the truth is much more important than winning.

�Premise 3: Because of the possible pain, �Premise 3: Because of the possible pain, people are afraid of debating over issues they really care.

�Conclusion: A deliberation is better than a debate in getting us at the truth.

�Evaluation: Premise 1 & 3: no evidence

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Counter Arguing Strategies

�Asking for clarification of terms: � I'd like a definition of “flashiest arguments”,

What do you mean by “at the beginning”?,

�Giving counter examples: � What if it's a presidential debate and the

Democrat suddenly says, "Oh, I see you've been right all along, I'm going to go out and register Republican."

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Counter Arguing Strategies

�Asking for evidence: � Aren't we missing a central piece of

evidence? We don't know whether people would be more willing to deliberate than debate. Would you be willing to try an debate. Would you be willing to try an experiment? We would poll whatever number of people you think would make a convincing sample to at least see what people think they'd prefer.

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HTCTLesson89 [Compatibility Mode]