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Logical Fallacies
What’s wrong with the way we think?
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Logical Fallacy
According
to Webster’s Dictionary, a
fallacy is an error in reasoning or a
flawed argument.
It’s
an argument that does not conform
to the rules of logic, but appears to be
sound.
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To err is human . . .
Where do we commonly see logical fallacies?
Fallacies are all around you…
 Advertisements

in magazines
T.V.
 Billboards
 Radio
Can you think of a place where there are NO
advertisements?
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How are we affected?
 What
might be the
impact of being told
that we are not smart,
pretty, handsome,
rich, clean, or good
enough?
 Or
that someone else
isn’t one of those
things?
 What
does the
casual acceptance
of surrounding
ourselves with
fallacies say about
us?
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Types of Logical Fallacies:
Ad hominem
 Ad
Hominem
(meaning “against
the person”)
attacks the person
and not the issue
 First, determine
whether the
personal attack is
relevant.
Example:

Bill Roberts has been
campaigning for the
library tax. But what I
want to know is what Bill
Roberts thinks he knows
about a library. He only
has an eighth grade
education, and I would
bet that my eighth grade
son has a higher IQ than
Bill does.
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Types of Logical Fallacies:
Appeals to Emotion
 Appeal
to emotions
manipulates people’s
emotions in order to
get their attention
away from an
important issue.
 The
appeal arouses
your feelings or anger,
fear, grief, love,
outrage, pity, pride,
sympathy, relief, etc
Example:

If you allow murderers to
be set free after serving
only 15 years, you are
giving them permission to
kill again.
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Types of Logical Fallacies:
Hasty Generalization

Hasty generalization (or jumping to conclusions) draws a
conclusion about a population based on a small sample.

Example: I’ve met two people in Nicaragua so far, and they were
both nice to me. So, all people I will meet in Nicaragua will be
nice to me.
-OR
Example: I do not believe that Dr. McKenzie is a trust-worthy
physician. Two of my friends were his patients, and he incorrectly
diagnosed both of their cases.
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Types of Logical Fallacies:
Stereotype
A
stereotype is a special and dangerous
form of the hasty generalization. There are
national, regional, religious, racial and
many other kinds of stereotypes.
 Example:
Don’t expect John McKenzie to
spend much on your date tonight. His
parents are Scotch, after all.
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Types of Logical Fallacies:
Circular Reasoning
 Circular
reasoning
is an attempt to
support a statement
by simply
repeating the
statement in
different or
stronger terms.

A confused student
argues: “You can’t give
me a C. I’m an A
student!”

A satisfied citizen says:
“Richardson is the most
successful mayor the
town has ever had
because he's the best
mayor of our history.”
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Task

In pairs, please discuss and provide examples to explain the
following fallacies:

Slippery Slope

Red Herring

Post hoc ergo propter hoc

Genetic Fallacy

Begging the claim

Begging the question

Either/or

Ad populum

Straw Man

Moral Equivalence