Reading Handbook page R24
FAULTY LOGIC/REASONING
Or...What is wrong with this statement?
So, what is faulty logic?
Let’s break it down.
Faulty = having faults or imperfect
Logic = reason or sound judgment
Therefore, faulty logic is an imperfect or
flawed reason.
Why learn this?
Learning to recognize faulty logic will help you
become a more astute consumer of products and
information.
#1 Type of Faulty Logic:
Circular Reasoning
DEFINITION: The writer (or speaker or ad)
supports a claim with restatements of that
same claim. The argument goes around and
around with the reason making the same claim
as the original argument.
EXAMPLE: John Upton is a wonderful
writer because he writes so well.
EXPLANATION: The second half of the
statement says basically the same thing as
the first half.
Circular Reasoning
#2 Type of Faulty Logic:
Overgeneralization
DEFINITION: The writer reaches
conclusions from a limited number of facts.
(Look for words such as all, every, and always.)
EXAMPLE: “I loved that movie we saw last
night with Brad Pitt. I am going to rent all of his
movies, and I am sure I’ll like all of them.”
EXPLANATION: It is an imperfect
judgment (or faulty logic!) to assume that you
will love all Brad Pitt movies just because you
loved one!
EXAMPLE: Enron was a large, corrupt
company, so all large companies are corrupt.
EXPLANATION: One example of
something does not make the statement true
in all cases. There are large companies that
are not like Enron and have perfectly honest
dealings.
Overgeneralization
#3
Type of
Faulty Logic:
False Cause
DEFINITION: An assumption is made that
one event causes the other when in fact, it did
not.
EXAMPLE: Our house was burglarized
right after that new family moved in next door.
EXPLANATION: This statement attributes
a false cause (new family next door) to the
effect (the burglary).
False Cause
False
Cause
#4 Type of Faulty Logic:
Oversimplification
DEFINITION:
This occurs when a single cause is assumed
to have created a problem or an issue. In
reality, the problem or issue may have been
created by a number of causes.
A complex situation is explained as if it were
much simpler than it is.
 EXAMPLE: The cause of the Civil
War was slavery.  EXPLANATION: The above
statement is too simplistic. Slavery was
only one of several reasons the Civil War
was fought. Oversimplification
#5 Type of Faulty Logic:
Commonly held opinion
DEFINITION:
An argument that is deemed correct just
because everyone else supposedly thinks it is
correct.
EXAMPLE: Everyone knows that cats
make better pets than dogs.

#6 Type of Faulty Logic:
Hasty Generalization
DEFINITION:
A conclusion is drawn from too little
evidence or from evidence that is biased
EXAMPLE: I got sick after eating at the
pizza place, so Italian food must be bad for
me.
EXAMPLE: After my son was
vaccinated for chicken pox, he developed
autism, so vaccinations must cause autism.
#7 Type of Faulty Logic:
Non Sequitur
(literally “it does not follow”
DEFINITION:
A statement that uses irrelevant “proof” to
support a claim. A non sequitur is
sometimes used to win an argument by
diverting the reader’s attention to proof that
can’t be challenged
EXAMPLE: I will probably flunk the
driving test. I was late for school today.
EXAMPLE: It rained today because I
washed my car.
#8 Type of Faulty Logic:
Either / or fallacy
DEFINITION:
A statement that suggests there are only
two choices available in a situation that
really offers more than two options
EXAMPLE: Either you eat a balanced
diet, or you will die before you are fifty.
EXAMPLE: You can support your country
by voting for me, or you can watch it fall to
pieces.
EXAMPLE: A new car may be expensive,
but do you want me to drive around in the
junk pile for the rest of my life?
#9 Type of Faulty Logic:
Personal attack or name-calling
(also called ad hominem,
which means “against the man”)
DEFINITION:
An attempt to discredit an idea by attacking
the person or the group associated with it.
Candidates often engage in name-calling
during political campaigns.
EXAMPLE: After Sally presents an
eloquent and compelling case for a more
equitable taxation system, Sam asks the
audience whether we should believe
anything from a woman who isn't married.
Now practice what you have learned.
What type of faulty logic is the
following statement?
STATEMENT: I argued with Mrs. Coulter
before I turned in my homework, so I got a bad
grade on my paper.
THE ANSWER: False Cause
WHY? The student suggests that because
he/she argued with his English teacher prior to
turning in a paper (cause), the result/effect
was a bad grade.
STRATEGY: Try to identify an end result or
effect. Ask yourself: Did the reason given really
cause the end result?
What is the faulty reasoning
in the following statement?
STATEMENT: I hated the movie because it
was the worst movie I ever saw.
THE ANSWER: Circular Reasoning
WHY? “...the worst movie I ever saw” is
basically the same thing as “I hated the
movie.” It’s saying the same thing.
STRATEGY: Look at the end of the
sentence. Is it really similar to the beginning? Is it
going around and around?
What is the faulty reasoning here?
STATEMENT: I know why you failed all
your classes last semester. You don’t study.
THE ANSWER: Oversimplification
WHY? There could be many reasons why
a student experiences difficulty in school.
Reducing the problem to one solution is
oversimplifying.
STRATEGY: Look for an effect that has
MANY possible causes.
What is the faulty reasoning here?
STATEMENT: You got a good grade on
your essay because the teacher likes you.
THE ANSWER: False Cause
WHY? This statement attributes the
effect (a good grade) to a false cause (the
teacher likes you).
STRATEGY: Look at the cause and effect.
Ask yourself: Is this really the cause?
What is the faulty reasoning here?
STATEMENT: Juan is an impressive
speaker because he always impresses his
listeners deeply.
THE ANSWER: Circular Reasoning
WHY? “He impresses his listeners deeply”
is basically the same thing as “Juan is an
impressive speaker.” The statement is going
around in circles.
STRATEGY: Look at the sentence
beginning and the sentence ending. Ask
yourself: Does it go around in circles?
What is the faulty reasoning here?
STATEMENT: All teenagers are
irresponsible.
THE ANSWER: Overgeneralization
WHY? All teenagers are NOT
irresponsible. This statement relies on
stereotypes and is an unfair conclusion based
on limited observations.
STRATEGY: Look for the context clues—
the word all. Ask yourself: Are all teenagers
irresponsible?
What is the faulty reasoning here?
STATEMENT: This class is awesome
because we do amazing things in here.
THE ANSWER: Circular Reasoning
WHY? “...we do amazing things” is very
similar to “This class is awesome.” Again, the
last half of the statement is similar to the first
half; it’s going around and around in a circle.
STRATEGY: Look at sentence beginnings
and sentence endings, the cause and effect.
Are they similar?
One last flawed statement...
STATEMENT: Teenagers have bad skin
because they don’t wash their faces.
THE ANSWER: Oversimplification
WHY? This answer argues that there is
only one reason for teenagers’ skin problems.
In fact, there are numerous causes.
STRATEGY: Look for a cause and effect
relationship. Ask yourself: Could there be more
than one cause that brings about the effect? If the
answer is yes, then the answer is too simple.
Identifying Faulty Reasoning
Reading Handbook, Section 5, page R25
DIRECTIONS: Number your paper 1—7.
Identify each logical fallacy in the Practice and Apply exercise on page
R25 and explain why you identified it as such.
Every sentence is a different type of logical fallacy.
Choose from these:
false cause,
evading the issue,
hasty generalization,
commonly held opinion,
circular reasoning,
oversimplification,
non sequitur
1. Everyone agrees that running is the best form of exercise.
2. All you need is a good pair of shoes and you’re ready to hit the road.
3. I’ve run a mile twice this week, so I should know.
4. As a result, I’ve slept better and the tone on my clarinet has improved.
5. When you run, your heart beats faster because your pulse rate
increases.
6. That means that your cells get more oxygen, which is the second most
common gas in the earth’s atmosphere. You also get to enjoy the beauty
of the world around you as you build up your stamina.
7. So if you don’t want to be a hopeless couch potato, get going and run
for your life!