 Logical
fallacies are flaws or gaps in logic
that undermine an argument.
 You should, of course avoid using logical
fallacies in your own writing; you should also
look for these when you’re critically reading
as well.
 There are many different types, but we’ll go
over those that are most commonly used.

A hasty generalization is a conclusion based on
insufficient evidence. Many stereotypes, for
example, are hasty generalizations.

Asian students are exceptionally intelligent.
Stereotyping is prevalent since we, as humans,
like to categorize and group people. We also
tend to see evidence that confirms our
previously held beliefs.
 Many hasty generalizations contain words like
“all,” “ever,” “always,” or “never”. Qualifiers
like “most,” “many” or “seldom,” can increase
accuracy and help you avoid making a hasty
generalization


An analogy points out similarities between things
that are otherwise different. They can be
effective when handled correctly. However, the
analogy can become faulty when there is an
assumption that the two items are comparable
when if fact they are not.
If we can put humans on the moon, we should be able
to find a cure for the common cold.
 Putting humans on the moon and finding a cure for
the common cold are both scientific endeavors, but
the problems confronting medical researchers and
space scientists are quite different.


When two events occur silumtaneously orone
after another, we tend to see causal
relationships between them: one caused the
other. However, there could be a third,
unnamed cause contributing to the outcome.
Therefore, explaining a causal relationship is
difficult and should be approached with care.
The chemistry course had a high failure rate.
Therefore, the professor was ineffective.
 What other causes might be contributing?




Large class size
Inadequate preparation of students
Lack of support resources like tutors on campus
 When
we boil down a situation so that there
appear to be only two options when in reality
there are more, we have used the either or
fallacy.

Either you support the President in everything he
says and does or you are not a patriotic
American.
 Claims
are backed by reasons. When the
relationship is between the claim and the
reason is unclear, a non sequitur fallacy has
been committed.
 Non sequitur is Latin for “does not follow”


Mary loves good food; therefore, she will be an
excellent chef.
How will enjoying food qualify her to be a chef?
What qualities do make people good chefs?
A
straw man fallacy sets up the counter
argument so that it is easy to tear down, a
misrepresentation of the opposition.

People who think abortion should be banned
have no respect for the rights of women. They
treat them as nothing but baby-making
machines. That's wrong. Women must have the
right to choose.
 Explaining
that we’ve followed a procedure
for a long time is not enough justification for
continuing that procedure.

The appeal to tradition was a common defense of
slavery prior to the Civil War. People in the
South explained that they knew no other way of
life, and therefore the practice had to continue.
 The
bandwagon fallacy is the assumption
that just because something is popular, it is
good/right/acceptable.

If all of your friends jumped off a cliff, would
you do it, too?
 When
doing research, citing relevant experts
in the field is key in establishing your ethos
and logos. If you cite an expert whose
expertise is in an unrelated field, you have
used the false authority analogy.

My friend, who is serving in the infantry in Iraq,
tells me that the government has a secret plan
for how to win the War that they won’t release
until after the election
 When
addressing the counter argument, it is
important to keep criticism relevant to the
presentation of ideas rather than attacking
people personally.
 “Ad Hominem” is Latin for “to the man”. It
is a personal attack.

Here’s what I think about what you have written:
anyone who opposes the death penalty for
murder is a criminal at heart.
 When
supporting a claim, you need to give
reasons and evidence to back it up. Circular
reasoning happens when, rather than giving
reasons to support your claim, you re-state
your claim in new words.

Wrestling is a dangerous sport because you can
get hurt while doing it.
 Arguing
that all members of a group are like
some other members of that group, or are
responsible for what those others have done.

Those who attacked the United States on
September 11, 2001 were Muslims; therefore, all
Muslims are potential terrorist threats to the
United States.
 To
greatly exaggerate the supposedly
inevitable future consequences of an action
by suggesting one small step will initiate a
process that will necessarily lead the way to
a much bigger result.

If you restrict my right to say whatever I want
anywhere I want however I want, this is the
beginning of totalitarianism in America.
 Drawing
attention away from the issue at
hand by focusing on an irrelevant issue as a
substitute for making a case.

You can’t trust Jim to do a good job as student
body president; he doesn’t dress with an up-todate sense of style.
 Read
through Rush Limbaugh’s article
“Sexual Harassment and the Feminist Front”
Look for logical fallacies as you read. See if
you can identify and label them by type.
 Now get into small groups of about 3 or 4 and
share your findings. Be prepared to share
your findings with the rest of the class.