Why dont these arguments work? Television cant be harmful to
children because it occupies their attention for hours and thus
keeps them off the streets Marijuana cant be all that bad. Everyone
knows about barroom brawls, but marijuana makes people peaceful
Shakespeare cannot have been a great writer, for he did not even
make up his own plots Doctors are all alike. They really dont know
any more than you or I do. This is the third case of faulty
diagnosis Ive heard of in the last month We ought to be guided by
the decision of our ancestors, for old age is wiser than youth
Slide 3
Why dont these arguments work? The end of a thing is its
perfection; death is the end of life; death is, therefore, the
perfection of life You can tell that Frank is a disreputable person
by the character of his associates, because people who go around
with somebody like Frank are the lowest type Comedian W.C. Fields
said he knew a sure cure for insomnia a good rest Im surprised at
you. A person of your culture and upbringing defending those
hoodlums!
Slide 4
What is a logical fallacy? Usually incorrect argumentation in
reasoning resulting in a misconception or presumption. Reasoning
must be potentially deceptive, it must be likely to fool at least
some of the people some of the time. In order for a fallacy to be
worth identifying and naming, it must be a common type of logical
error. A fallacy isnt a false conclusion but a weak one.
Slide 5
Why Study Fallacies? Why study how to reason incorrectly; why
not just study how to reason correctly? Even if you are right100%
of the time, others may not be. Its like having a road map that
shows how to get from point A to point B.
Slide 6
Common Fallacies: Ad hominem Against the man, against the
person Attacks the persons character, habits, morals, or
personality Example: Teenagers dont know anything about true love.
How could they; they are so young and inexperienced!
Slide 7
Slide 8
Common Fallacies: The Appeals Appeal to: Authority: I'm not a
doctor, but I play one on Greys Anatomy. I choose Advil for all my
headaches. Emotion: The new UltraSkinny diet will make you feel
great. Enjoy the admiring stares of the opposite sex. You will know
true happiness if you try our diet! Fear: I really need to get an A
in this class. My father, the principal, would really appreciate
that. Pity: I'm positive that my work will meet your requirements.
I really need the job since my grandmother is sick. Tradition: Of
course this mode of government is the best. We have had this
government for over 200 years and no one has talked about changing
it in all that time. So, it has got to be good.
Slide 9
Common Fallacies: Bandwagon a threat of rejection by one's
peers (or peer pressure) is substituted for evidence in an
"argument. Idea X is popular. Therefore, X is correct Example: Most
people believe Michael Jackson is the greatest entertainer of our
time. Therefore, Michael Jackson is the greatest entertainer of our
time.
Slide 10
Slide 11
Common Fallacies: Begging the question the premises include the
claim that the conclusion is true or (directly or indirectly)
assume that the conclusion is true similar to: circular argument
Example: "If such actions were not illegal, then they would not be
prohibited by the law. Have you stopped cheating in school?
Slide 12
Common Fallacies: Dicto Simpliciter acceptable exception is
ignored or eliminated a general rule is treated as universally true
regardless of the circumstances Example: "Birds normally can fly.
Tweety the Penguin is a bird. Therefore, Tweety can fly."
Slide 13
Common Fallacies: Equivocation a word is incorrectly (on
purpose) used to make an argument doublespeak Example: A feather is
light. What is light cannot be dark. Therefore, a feather cannot be
dark.
Slide 14
Common Fallacies: False Dilemma only two alternatives are
considered, when in fact there are additional options;
oversimplification Black and white thinking Example: Either you're
for me or against me.
Slide 15
Common Fallacies: Hasty Generalization conclusions made about a
population based upon a sample which is too small to be
representative often committed because of bias or prejudice
Example: Smith is from England. While on a trip to the US to visit
Penn State, he sees two white squirrels. Back in England he tells
his family that all American squirrels are white.
Slide 16
Common Fallacies: Non sequitur conclusion does not follow from
its premises disconnection between the premise and the conclusion
Example: Life is life and fun is fun, but it's all so quiet when
the goldfish die.
Slide 17
Common Fallacies: Poisoning the Well involves trying to
discredit what a person might later claim by presenting unfavorable
information (be it true or false) about the person Example: Don't
listen to him, he's a liar.
Slide 18
Common Fallacies: Post Hoc, Ergo Propter Hoc after this,
therefore because of this Example: Every time I take a vitamin I
get sick. Vitamins make me sick.
Slide 19
Common Fallacies: Red Herring any argument in which the
premises are logically unrelated to the conclusion commits this
fallacy. an irrelevant topic is presented in order to divert
attention from the original issue Example: I know I forgot to
deposit the check into the bank yesterday. But, nothing I do
pleases you.
Slide 20
Common Fallacies: Slippery Slope undesirable outcome is the
guaranteed result of a chain of actions. Therefore, the first step
should never be taken. a person asserts that some event must
inevitably follow from another without any argument for the
inevitability of the event in question. Example: You can never give
anyone a break. If you do, they'll walk all over you.
Slide 21
Common Fallacies: Straw Man a person simply ignores a person's
actual position and substitutes a distorted, exaggerated or
misrepresented version of that position Example: Senator Jones says
that we should not fund the attack submarine program. I disagree
entirely. I can't understand why he wants to leave us defenseless
like that. Person A: Our society should be taxed less. Person B: It
is unjust to promote a society that neglects the poor.
Slide 22
Common Fallacies: Tu Quoque you too Fallacy committed when it
is concluded that a person's claim is false because: it is
inconsistent with something else a person has said, or what a
person says is inconsistent with her actions. Example: Peter: Based
on the arguments I have presented, it is evident that it is morally
wrong to use animals for food or clothing. Bill: But you are
wearing a leather jacket and you have a roast beef sandwich in your
hand! How can you say that using animals for food and clothing is
wrong! or I know you are but what am I?
Slide 23
Common Fallacies: Two Wrongs Make a Right a person "justifies"
an action against a person by asserting that the person would do
the same thing to him/her attempt to justify a wrong action by
pointing to another wrong action Example: After leaving a store,
Jill notices that she has underpaid by $10. She decides not to
return the money to the store because if she had overpaid, they
would not have returned the money.
Slide 24
Spot the fallacy!
http://www.thedailyshow.com/watch/thu-june-28-
2007/immigrant-disease
http://www.thedailyshow.com/watch/thu-june-28-
2007/immigrant-disease
Slide 25
Shes a witch!
Slide 26
Homework Look through newspaper articles (online or paper),
print advertisements, or anything you find that is relevant, and
find 5 logical fallacies. In 1 paragraph per fallacy, state: The
source The audience The message/how is it trying to persuade the
audience The fallacy Explanation/examination of fallacy Attach the
article to your paper and hand-in Tuesday, November 15 th. Thank
you!