Common Logical Fallacies
AP Language and Composition
Fallacies are statements that may sound reasonable or true but are not logically defensible and may actually be
deceptive. When your readers detect them, such statements can backfire and turn even a sympathetic
audience against your position. Here are some of the more common fallacies that you should try to avoid:
Fallacy
Definition
Example
Begging the Question
Begging the question is a logical
fallacy that assumes in the premise
what the arguer is trying to prove in
the conclusion. This tactic asks
readers to agree that certain points
are self-evident when they are not.
The unfair and shortsighted legislation
that limits free trade is clearly a threat
to the American economy.
Restrictions against free trade may or
may not be unfair and shortsighted, but
emotionally loaded language does not
constitute proof. The statement begs
the question because it assumes what
it should be proving-that restrictive
legislation is dangerous.
Ignoring the Question
a question is set up so that
argument is shifted to new ground,
or an appeal is made to some
emotional attitude having nothing
to do with the logic of the case.
You should talk about the apartheid
philosophy in Africa. Do you know what
Americans did to the Indians?
Argument from Analogy
An analogy is a comparison of two
unlike things. Although analogies
can explain an abstract or unclear
idea, they are not proof. An
argument that is based on an
analogy and ignores important
dissimilarities between the two
things being compared is a fallacy.
The overcrowded conditions in some
parts of our city have forced people
together like rats in a cage. Like rats,
they will eventually turn on one
another, fighting and killing until a
balance is restored. It is therefore
necessary that we vote to appropriate
funds to build low-cost housing.
No evidence is offered that people
behave like rats under these or any
other conditions. You should not
assume that simply because two things
have some characteristics in common,
they are alike in other respects.
Personal Attack (Argument
Ad Hominem)
This fallacy tries to turn attention
away from the facts of an issue by
attacking the motives or character
of one's opponents.
The public should not take seriously Dr.
Mason's plan for upgrading county
health services. He is a recovering
alcoholic whose second wife recently
divorced him.
This attack on Dr. Mason's character
says nothing about the quality of his
plan. Sometimes a connection exists
between a person's private and public
lives--for example, a case of conflict of
interest. But no evidence of such a
connection is given here.
Common Logical Fallacies
AP Language and Composition
Hasty or Sweeping
Generalization
A form of jumping to a conclusion,
this fallacy occurs when a conclusion
is reached on the basis of too little
evidence.
Our son Marc really benefited socially
from going to nursery school; I think
every child should go.
Perhaps other children would benefit
from nursery school, and perhaps not,
but no conclusion about children in
general can be reached on the basis of
one child's experience.
False Dilemma (Either/Or
Fallacy)
This kind of argument assumes that
there are only two alternatives
when more exist.
We must choose between life and
death, between intervention and
genocide. There can be no neutral
position on this issue.
An argument like this oversimplifies
issues and forces people to choose
between extremes instead of exploring
more moderate positions.
Equivocation
This fallacy occurs when the
meaning of a key term changes at
some point in an argument.
Equivocation makes it seem as if a
conclusion follows from premises
when it actually does not.
As a human endeavor computers are a
praiseworthy and even remarkable
accomplishment. But how human can
we hope to be if we rely on computers
to make our decisions?
The use of human in the first sentence
refers to the entire human race. In the
second sentence human means
"merciful" or "civilized." By subtly
shifting this term to refer to qualities
characteristic of people as opposed to
machines, the writer makes his
argument seem more sound than it is.
Red Herring
This fallacy occurs when the focus of
an argument is changed to divert
the audience from the actual issue.
So far Mr. Bradley, our state
representative, has spent months
fighting the proposed tax bill. The
governor has said that she needs the
revenue that this bill offers, but Mr.
Bradley refuses to support her. One can
only wonder if Mr. Bradley has nothing
better to do in his own district than to
spend so much time opposing the
governor.
The focus of this argument should be
the merits of the tax bill. Instead, the
writer shifts to the irrelevant issue of
Mr. Bradley's spending too much time
opposing the governor.
You Also (Tu Quoque)
This fallacy asserts that an
opponent's argument has no value
because the opponent does not
follow his or her own advice. In
How can that judge favor stronger
penalties for convicted drug dealers?
During his confirmation hearings, he
Common Logical Fallacies
AP Language and Composition
other words, an opponent is
accused of acting in a way that is not
in line with his or her stated
position.
admitted having smoked marijuana
when he was a student.
Appeal to Doubtful
Authority
Often people will attempt to bolster
an argument with references to
experts or famous people. These
appeals are valid when the person
quoted or referred to is an expert in
the area being discussed. They are
fallacies, however, when the
individuals cited have no expertise
concerning the issue.
According to Ted Koppel, interest rates
will remain low during the next fiscal
year.
Although Ted Koppel is a respected
journalist, he has no background in
business or finance. In the final
analysis, his pronouncements about
interest rates are no more than a
personal opinion or, at best, an
educated guess.
Misleading Statistics
Although statistics are a powerful
form of factual evidence, they can
be misrepresented or distorted in an
attempt to influence an audience.
Women will never be competent
electricians; 50 percent of the women
in the electrical technology section
failed the exam.
Here the writer has neglected to
mention that there were only two
women in the course. Because this
statistic is not based on a large enough
sample, it cannot be used as evidence
to support the argument.
Post Hoc, Ergo Propter Hoc
(After This, Therefore
Because of This)
This fallacy, known as post hoc
reasoning, assumes that because
two events occur close together in
time, the first must cause the
second.
Every time a Republican is elected
president a recession follows. If we
want to avoid another recession we
should elect a Democrat.
Even if it is true that recessions always
occur during the tenure of Republican
presidents, no causal connection has
been established.
Non Sequitur (It Does Not
Follow)
This fallacy occurs when a statement
does not logically follow from a
previous statement.
Disarmament weakened the United
States after World War I. Disarmament
also weakened the United States after
the Vietnam War. For this reason, gun
control will weaken the United States.
The historical effects of disarmament
have nothing to do with current efforts
to control the sale of guns. Therefore,
the conclusion is a non sequitur.
Hypothesis Contrary to Fact
Beginning with a premise that is not
necessarily true and then drawing
conclusions from it.
If I had not had Mr. Smith for a teacher,
I would never have understood
Algebra.
Bandwagon
As in jump on the bandwagon.
Everybody does or believes this, so you
should, too.
Common Logical Fallacies
AP Language and Composition