Critical thinking

1. 1
CRITICAL THINKING
I. Chapters 6, 7, 8, 11 and 12
1.Fallacies of Insufficient Evidence (Chapter 6)
2.Analyzing Arguments (Chapter 7)
3.Evaluating Arguments (Chapter 8)
4.Inductive Reasoning (Chapter 11)
5.Finding, Evaluating and Using sources (Chapter 12)
II. Application of Critical thinking

2. Analyzing and Evaluating an Argument

3. 3
How reliable are your senses?

4. 4
How reliable are your senses?

5. 5
Structures of an Argument
(DEDUCTION and INDUCTION)
INDUCTIVE
CONCLUSION 1
DEDUCTIVE
CONCLUSIONSTRICT LOGICAL NESCESSITYPREMISE(S)
PREMISE(S) LIKELY OR PROBABLY
Conclusion 2
Conclusion 3

6. 6
DEDUCTIVE REASONING
Chapter 4
INDUCTIVE REASONING
Chapter 4
THE VALIDITY
OF DEDUCTIVE REASONING
THE VALIDITY STRENGTH
OF INDUCTIVE REASONING
VEEN DIAGRAM
Chapter 9
TRUTH TABLE
Chapter 10
FALLACIES
(Chapter 5, 6)
EVALUATIING
ARGUMENT
(Chapter 7, 8, 11, 12)
ARGUMENT
Chapter 1,2,3
(VALID or
INVALID)
Mistakes in
Reasoning and Evidences
Strong or Weak

7. 7
The concept of Relevance
Ex 1: Babara is a traditional woman(p*).
Thus, she may enjoy cooking (C1).
If (p*) is TRUE then we can see (C1) is
TRUE.
=> (p) is relevant to (C1)
Ex 2: Dog are Cat (q*). Cat are feline (r*).
So, Dog are feline (C2)
⇒ If (q*) and (r*) are TRUE then (C2)
is TRUE.
⇒ (p) and (r) are relevant to (C2)
Ex 2: Cherios is a good student(s*).
Because he knows how to
cheat on exams(C3).
⇒ If (s*) is TRUE then (C3) is
FALSE
⇒ (s) is relevant to (C3)
A RELEVANT PREMISE: If it TRUE, it
can help you to know the
conclusion is TRUE or FALL
A positively relevant premise = A premise (even TRUE or FALSE) gives the
logically conclusive reason for accepting the conclusion
⇒ p, q, r are positive relevant premises
A negatively relevant premise = the premise, if TRUE, gives reason for
thinking the conclusion is FALSE
⇒ s is a negative relevant premise

8. Irrelevant premises
Ex 3: Tom likes playing piano (p*). Therefore, he may like cooking(C).
Ex 4: UCLA is one of the best universities in USA. So, we can see the American
educational system is too open.
(p*) Do neither support nor against (C)
=> A statement is irrelevant to another when it counts neither support to
nor against that other statement.
8

9. 9
“Strong” or “weak” inductive argument
Argument 1:
We can conclude that children are
innocent. Because they are
friendly, they love everyone and
always believe in adults.
Argument 2:
We can conclude that children are
innocent. Because they are
friendly and always believe in
adults.
Argument 3:
Argument 3: We can conclude that
children are innocent. Because they are
very dependent and need to be
educated.
What is the strong inductive
argument?
- All premises are positive relevant
to the conclusion.
-The conclusion follows necessarily
from the premises.

10. 10
“Analyze”, “Diagram” and “Evaluate” an inductive argument
Argument 1: We can conclude that
children are innocent(C). Because
they are friendly(p*), they love
everyone(q*) and always believe in
adults(r*).
Argument 2:We can conclude that
children are innocent(C). Because
they are friendly(p*) and always
believe in adults(r*).
Argument 3: We can conclude that
children are innocent(C). Because they
are very dependent(s*) and need to be
educated(t*).
C
rqp
C
p r
C
s t

11. 11
“Strong” or “weak” inductive argument
Argument 1: We can conclude that
children are innocent(C). Because
they are friendly(p*), they love
everyone(q*) and always believe in
adults(r*).
Argument 4: We can conclude that children
are innocent(C). Because they are
friendly(p*), very dependent(s*), they
love everyone(q*) and always believe
in adults(r*)
C
r*q*P*
C
r*q*P* s*

12. Logically Irrelevant Premise
Human is mortal. Bill Gate is human. So, Bill Gate is mortal. I am not Bill Gate.
Thus, I am not mortal.
Analyze the argument, we have:
Human is mortal(p*). Bill Gate is human(q*). So, Bill Gate is mortal (C1). I am
not Bill Gate (s*). Thus, I am not mortal (C2).
12
C1
C2
p q
s
p q
C1 s
C2

13. 13
Decide which of the individual piece/s of information would strengthen the
argument if added
Having students work in groups lets them practice the skills they are
learning. It is an efficient way to develop their active learning.
a) Speaking in front of the whole class can be scary.
b) Breaking students up into groups not only develops social skills useful in
the professional environment for which they are training
c) Most of good students say that they do not get any benefits from group
work
d) Group work gives students a chance to perform in a supportive
environment that help them to become more confident.
e) Students who like to clean on others feel comfortable in group work.
f) Most of students improve their communication skills via group work.

14. 14
Having students work in groups lets them practice the skills they are
learning. It is an efficient way to develop their active learning.
a) Speaking in front of the whole class can be scary.
b) Breaking students up into groups not only develops social skills useful in
the professional environment for which they are training
c) Most of good students say that they do not get any benefits from group
work
d) Group work gives students a chance to perform in a supportive
environment that help them to become more confident.
e) Students who like to clean on others feel comfortable in group work.
f) Most of students improve their communication skills via group work.
Answer

15. Refuting Arguments
Lecture Notes © 2008 McGraw Hill Higher
Education
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ARGUMENT
PREMISE/S CONCLUSION
TRUE
FALL
Logically
follow the premise/s
Not follow the
premise/s
AND
OR
WE REJECT THE ARGUMENT
WE ACCEPT
THE
ARGUMENT

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Refuting Arguments
There are two ways to refute an argument:
1) Show that a premise—or a critical
group of premises—is false or
dubious.
2) Show that the conclusion does not
follow from the premises.

17. APPLICATIONS OF CRITICAL THINKING
1) Learning: critique on information and experiences
2) Research, Project, Paper: product logical reasoning,
make deductive and inductive argument, use
sources, references…
3) Life: evaluate information to make right decisions,
recognize fallacies
4) Work: Make decisions => (Plan-Do-Check-Act)

18. Application:
Structure of your Group Presentation
and Final Paper

19. Structure of your Group
Presentation and Final Paper
• Cover: Topic, Group and Students name
• Index
• Content:
Page 1-2: Introduction the importance of Topic
(Requirement: For each argument you must show the source of
references)
EX: Many Vietnamese students have shock culture when studying abroad
(Nguyen, 2012)

20. Structure of your Group
Presentation and Final Paper
Page 2-4: Present your research questions and
Questionnaire
(Requirement: Use Diagrams to show the relationship
between each research question and survey
questions)
Research
Question 1:…..
Survey question 1:…
Survey question 2:…
Survey question 3:…

21. Research Question 1: How
do IU students think about
to study in Vietnam?
Survey question 1: What do you think
are advantages when studying VN?
Survey question 2: What do you think
are advantages when studying VN?
What are FALLACIES you can commit in your
questions?

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I agree with you that
we are very tired …
OKKKK…I see you think
that both of them can’t be a
good president
Are you tired of Bronco
Bamma and Mitt Romney
and they can’t be good
presidents?

23. Examples
• Question 1: Do you agree that homosexual and same sex marriage
should be accepted? (YES/NO)
• Question 2: Do you think that Vietnamese educational curriculums
and teaching methods now are update? (YES/NO)
• Question 3: Can you see that Tom can not answer my question and
he is a bad student ?
Lecture Notes © 2008 McGraw Hill Higher
Education
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1) Loaded question are multiple questions “rolled up” into one
1 and 2 are “Fallacies of Loaded question”
2) The arguer asks a question that contains an “unfair” or
“unwarranted presupposition”
=> 3 is “Fallacies of unwarranted presupposition”

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“Fallacies of unwarranted
presupposition”
EX 2: Do you think automobile makes the transportation in HCM
city go from bad to worse?
EX 3: Why did you cheat on your exams?
EX 4: Have you stopped cheating on your exams?

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Inductive Generalizations
• Generalization: statement made about all or most
members of a group.
• Inductive generalization: inductive argument that relies
on characteristics of a sample population (i.e., a portion
of the population) to make a claim about the population
as a whole.
– i.e., an inductive argument with a generalization as a
conclusion.
• Example: All the catfishes caught in Mekong river have
been less than 1lb. So, most of the catfishes caught in
the Mekong river are less than 1lb.

26. Structure of your Group
Presentation and Final Paper
• Page 4-5: Describe your targets
Describe:
- people who answer your questionnaire and your interviewees
- the method of collecting information (how do you choose your
target, how do you contact them, what tool you use to record
data…)
• What are FALLACIES you can commit in
your sampling?

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Sorry, we don’t have it.
You can either buy an HP
or Vios laptop, but you
don’t want a Vios, so you
must buy an HP.
I am looking for a
Dell laptop
Fallacy of False Alternatives

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If you don’t elect me, then the rate
of jobless will increase. I’m sure
that you don’t want the rate of
jobless will increase. So, elect me!
What now can prove that
after you select him, the
rate of jobless will be
decrease. Obama’s
argument is a fallacy of
False Alternative.

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False Alternatives
• False Alternatives = when an argument says there are only “n
options” when there are actually “more than n”.
• What are FALLACIES you can commit in your sampling?
- You can not interview the people that can give you accurate
information, thus, you interview your friends, roommates!

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Hasty Generalization
• …occurs when one draws a general conclusion from
a sample that is biased or too small.
–Biased sample: I polled 1,000 American scientists,
only 25 of them believed in God. I guess most
Americans don’t believe in God anymore.
–Too small of a sample: I asked 05 professors at
VNU if they believed in their students, and all of
them did. It can be seen that most professors in
VN believe in their students.

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Some students I have met in University
of Technology speak English better
than IU students. I think students of
University of Technology speak
English better than IU students.
Research on climate change in
South-Eastern Region in
Vietnam shows that the climate
change cause by industrial
pollution. Based on this, we can
conclude that the climate
change in Mekong Delta Region
is caused by the algricutural
pollution.
Fallacy of Hasty
Generalization

32. Taking notes
• Focus on your aims
⇒ Be clear about your project aims, the purposes of your interview... and
note all issues that relate to your aims or purposes.
• Be accurate
⇒ Note exactly what you heard, read, see without any bias
• Be precise
⇒ Note in details what you heard, read, see
• Be clear
=> Use clear language when noting

33. Structure of your Group
Presentation and Final Paper
Page 5-10: Present the results of Questionnaire
(Describe how do you analyze data; use
statistics analysis and pie chats or graphs) and
and present your explanations of the results
Page 10-12: Present the results from Interviews
(select the adequate quotes from the
interviews) and your explanations of the
results

34. Structure of your Group
Presentation and Final Paper
Page 13-15: Introduce each research question and the answer
for it that follow the results.
EX:
1) Research question 1:
What students think about homosexual?
From the research, it can be conclude that most students
perceive homosexual a desease. A few of the know the
effects of social environment that can cause homosexual.
What are fallacies you can commit in your
conclusion?

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Statistical Arguments
• Statistical arguments go “the other way.” They take
generalizations and draw conclusions about smaller samples of
the population (usually individuals).
• Example:
1. You’re a college student
2. 90% of college students want no cumulative final.
3. So you probably don’t want a cumulative final.
• The more “broad” the conclusion the better.
• The higher the original percentage, the better.
• Usually, if the percentage is around 50%, we will call the
argument unreliable, even if it is more likely than not that the
conclusion is true.
– A “rule of thumb”: if it is would reasonable to bet on it, then it is
reliable.

36. Making Inductive Generalizations stronger by
making conclusions weaker.
• Ex 1: All the catfishes
caught in Mekong river
have been less than 1lb.
So, all the catfishes
caught in the Mekong
river are less than 1lb.
• Ex 2: All the catfishes
caught in Mekong river
have been less than 1lb.
So, most of the
catfishes caught in the
Mekong river are less
than 1lb.
=> stronger
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Johnson: We have to conclude
that Mr. A‘s corruption did
happened. Because no one has
proven that there was not !
No one has prove this
doesn’t mean it is true !
Johnson’s argument is
“a fallacy of appeal
to ignorance”

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Appeal to Ignorance
• Appeal to Ignorance = Fail to prove something
false and then, conclude that it is true (or visa-
versa).
– e.g., There must not be cheating in IU exams. We
have never found any.
Note:
Special rules: e.g., “innocent” until “proven guilty”.

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Last week, I eat a lot of garlic
that were cooked together with
fried seafood, and this morning
I see my skin was dry! It is
clear that garlic made skin dry.
Fallacy of Questionable Cause
Questionable Cause occurs when one
claims, without sufficient evidence, that one
thing is the cause of something else.

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Oversimplified cause fallacy
EX 1: There are 2.5% students of
chemistry class cheat on their
exam. That shows the
chemistry lectures were not
good.
(Students cheat because they did
not understand the lectures;
or they are lazy to learn…)
- Oversimplified cause fallacy:
suggesting that A is the cause
of B when clearly B has many
causes.

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Questionable Cause
• EX 2
I drank the ginseng tea and I
was better by the next
day. The tea must have
made me better.
• The post hoc fallacy:
suggesting that A causes
B just because A came
before B.

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Questionable Cause
• EX 3:
I every morning this week I
ate bananas, and every
day I failed an exam. I
should stop eating
bananas so I can pass my
exams.
• Mere correlation fallacy:
suggesting that the
constant conjunction of A
and B entails that they
are causally related.

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My father is tall, friendly and
intelligent, he is very faithful to
my mother. My boy friend is tall,
friendly and intelligent. So, he will
be very faithful to me.
Fallacy of Weak Analogy

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The Slippery Slope
• …fallacy is committed when one claims, without sufficient
evidence, that a seemingly harmless action will lead to a
terrible one.
– e.g., Dr. Perry has proposed that we legalize physician-assisted
suicide. No sensible person should listen to such an proposal. If we
allow physician-assisted suicide eventually there will be no respect
for human life.
• Common form: A leads to B, and B leads to C, and C to do D,
and we really don’t want D. Thus, we shouldn’t do A.
• Exception:
– If one presents good evidence that “A” will lead to “D,” and if D
should be avoided, then the conclusion that A should be avoided
is justified.

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Inconsistency
• …the fallacy of inconsistency is committed when an arguer
espouses two logically contradictory claims.
– e.g., Nobody goes there anymore; it’s too crowded.
• Common form
– A and not A.
• The only exceptions to this rule are equivocations:
– Bob is dead even though he isn’t.
• If you mean “he’s emotionally dead, even though he isn’t physically dead”
then you are not contradicting yourself… you are just being unclear (by
being ambiguous).
• But the exact same thing can never be both true and false at
the same time.

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Tom’ s argument is “a fallacy of Inappropriate appeal to authority”
Tom: My barber says that Einstein’s general theory
of relativity is a lot of hogwash. So, Einstein wasn’t
as smart as everybody think he was
Prof Brenda: The
source (the barber) is
not a genuine authority
on the subject at issue
(Einstein’s general
theory)

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Examples
• Ex 1: “In recent years, there is a trend towards homosexual in
Vietnamese young people”. (Tran Vinh - Tuoitre online).
=> Do you think that this can be used as a fact?
• EX 2: “Hotels in Vietnam are really good”, a tourist says.
⇒ Do you think that this can be used as a fact?
• 3: My friend who is studying in FPT University says that it is the best
university in Vietnam.
=> Do you think that this can be used as a fact?

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Inappropriate Appeal to Authority
• Inappropriate Appeal to Authority = citing an authority
who is unreliable.
• Ways we can question reliability:
– Are they an authority/expert?
– Are they biased?
– …

49. Using sources and References
• Scientific books (Who is its author?)
• Scientific Journals (See its impact factors?)
• Research (check the research methodology)
• Database (National Database, …)

50. Using sources and References
1. Use the source to get information
2. References for your statements
EX 1: In Vietnamese education, mathematics has been seen as a system of rules and
algorithms taught to students without references to its origin and cultural setting.
Mathematics is taught from the so-called mechanistic point of view, providing
pupils with static and clear-cut knowledge (Wubbels, Korthagen, & Broekman,
1997).
References
Wubbels, Th., Korthagen, F. A. J., & Broekman, H. G. B. (1997). Preparing teachers for
realistic mathematics education. Educational Studies in Mathematics, 32, 1–28.
EX: Many Vietnamese students have shock culture when studying abroad (Nguyen,
2012)
References
Nguyen. A Tuan, Studying the trend to study abroad of Vietnamese students, Journal
of International Education, 32, pp.23-35.

51. Paraphrase
• Paraphrase : to make longer arguments becomes tedious => Paraphrasing
EX: Many people are smoking. You are smoking also. I see you smoke a lot every day.
That can damage your lung and cause you cancer.
1. Be accurate: don’t misrepresent
2. Be clear: Take un-clarity and make it clear
3. Be Concise: get to the bare essentials
4. Be Charitable
– Bad paraphrase: Cigarette smoking guarantees that you will get lung cancer.
Continue to smoke and you will be unhealthy.
– Good paraphrase: Cigarette smoking is a positive causal factor that increases
the risk of lung cancer. Therefore, if you continue to smoke, you risk being
unhealthy.
Lecture Notes © 2008 McGraw Hill Higher
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52. Standardization
• Standardization: Finding missing premises and conclusions
• EX: Many people are smoking. You are smoking also. I see
you smoke a lot every day. That can damage your lung and
cause you cancer.
=> Paraphrase: Cigarette smoking is a positive causal factor
that increases the risk of lung cancer. If you smoke, you
risk being unhealthy.
• e.g., I see you are smoking a lot everyday (missing
premise). Cigarette smoking is a positive causal factor that
increases the risk of lung cancer. Therefore, if you
continue to smoke, you risk being unhealthy.

53. Announcement
• Group presentation: DEC 22nd
- 31st
2014 or after Final Exam
(check your email to get the schedule of your group
presentation informed by Mrs. Thao)
• Date of Critical thinking final exam: JAN 5th
2014
• Deadline to submit your final paper: JAN 12th
2015
• Group evaluation (use the evaluation form in the Guideline):
have a group meeting to evaluate each members (his/her
contribution to the group presentation and final paper) and
attach the evaluation form to your final paper.
=> Individual score (A:100% the group score; B: 75%; C;50% and
D:0%)