1. What Is Critical Thinking?
What Is Critical Thinking?
Exercise 5.1:
p. 109 Critical Thinking
© 2012 Wadsworth, Cengage Learning

2. I. Reasoning: Induction vs. Deduction
I. Reasoning: Induction vs. Deduction
Inductive arguments go from Deductive arguments go from
specific observations to general broad generalizations to specific
conclusions conclusions
© 2012 Wadsworth, Cengage Learning

3. I. Reasoning : Relevance and Adequacy
I. Reasoning : Relevance and Adequacy
Two things are required to judge the soundness of an argument:
Relevance Adequacy
Look at an example: Now look at this example:
“I don’t see why all students have “Everyone taking Math 100 failed the
to take an introductory writing test last Friday. I took the test last
course. It’s a free country. Students Friday. Therefore, I will probably get
shouldn’t have to take courses they an F in the course.”
don’t want to take.”
How many tests are left in the
Is the statement “It’s a free country course? What other assignments
relevant? What does living in a free figure into students’ grades? The
country have to do with courses that information present may not be
community college students are adequate to predict an F in the
required to take? Nothing. course.
© 2012 Wadsworth, Cengage Learning

4. I. Reasoning: Analyzing Arguments
I. Reasoning: Analyzing Arguments
Sound or Unsound?
Is it Relevant?
Is it Adequate?
Is it Logical?
The aim of argument, or of discussion,
should not be victory, but progress.
Joseph Joubert, French moralist
© 2012 Wadsworth, Cengage Learning

5. I. Reasoning: Assessing Assumptions
I. Reasoning: Assessing Assumptions
Assumptions are things you
take for granted, and they
can limit your thinking.
Understand your own
assumptions and see an
argument in new ways.
“One day Kerry celebrated her
birthday. Two days later her older
twin brother, Harry, celebrated his
birthday. How could that be?”
Think! What assumptions
are you making about this What we need is not the will to believe, but
puzzle? the will to find out. Bertrand Russell, British
© 2012 Wadsworth, Cengage Learning
philosopher, logician, and mathematician

6. I. Reasoning: Considering Claims
I. Reasoning: Considering Claims
Generally speaking, be wary of claims that:
 are supported by unidentified sources
(“Experts claim . . . ”).
 are made by a person or company who stands to gain
(“Brought to you by the makers of . . .”).
 come from a a single person claiming his experience as
the norm (“I tried it and it worked for me!”).
 use a bandwagon appeal (“Everybody’s doing it.”).
 mislead with statistics (“over half” when it’s really only
50.5 percent).
© 2012 Wadsworth, Cengage Learning

7. Simple vs.
Simple vs.
Complex
Complex
Reasoning
Reasoning
p. 113
© 2012 Wadsworth, Cengage Learning