Transcript Fallacies • Fallacies are Flaws in Reasoning, Appeals, Language

Fallacies
• Fallacies are Flaws in Reasoning, Appeals,
Language
Fallacies in Reasoning
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Hasty Generalization
Composition
Division
Non-Sequiter
Circular Reasoning
• Ad Hominem
• False Dichotomy
• Post Hoc Ergo Propter
Hoc
• Slippery Slope
Hasty Generalization
(secundum quid)
• Offers conclusion based on insufficient
information
• Too few or non-representative examples
Hasty G
• All Native Americans walk single file, at
least the one I saw did.
• The first five women I saw in town were
women. Only women live here.
• My first paper was an “A” so I will
probably get an “A” in the course.
Refutation using hasty
generalization
• My opponent tells you that many innocent
people have been executed with the death
penalty.
• However, if you examine her evidence,
there is only one innocent person presented.
• She can’t establish a reasonable pattern of
generalization with only one case.
Fallacy of composition
• Unwarranted assumption that what is true of
the part is true of the whole.
Compostion
• Some Americans are poor so all Americans
must have a poor standard of living.
• If you like eggs, peanut butter, bananas and
tuna, I’m sure will like this dish I just made
from all four.
• John McCain, a Republican favors
campaign finance reform so all Republicans
must favor campaign finance reform.
Refutation using composition
• John tries to get you to believe that Greece
was a militaristic nation.
• But note that his evidence only
demonstrates that a single Greek state,
Sparta, was war oriented.
• So I would say he hasn’t proven that all of
Greece was warlike, only Sparta. His
conclusion in unwarranted.
Fallacy of division
• Unwarranted assumption that what is true of
the whole is true of the parts
Division
• The U.S. has a high standard of living. So,
no American is poor.
• If you like cake, I’m sure you will like pure
carbon,oxygen, and hydrogen, as cake is
made of all three.
• The ball is blue, therefore the atoms that
make it up are blue.
Refutation using division
• The reasoning from Mary is wrong when she tells
you the entire brain is capable of consciousness.
• I will grant that she is right when she says that
there are cells in the brain that are capable of
consciousness.
• But, my evidence will demonstrate that there are
only a few of these cells in the brain and claiming
that the entire brain is a conscious organ clearly
overclaims her position.
Non-sequiter
• Irrelevant arguments that make assumptions
that do not follow from the information
provided.
Non-sequiter
• Sex crimes are often the result of an
unrestrained libido, so castration is an
appropriate punishment for such crimes.
• The Los Angeles times recently won 5
Pulitzer prizes. USA Today has one of the
best sport sections in America. You should
watch The Real World on MTV because it
is a great program.
Refuting a non-sequiter
• Look, Enrique’s argument just doesn’t
make sense.
• The fact that the L.A. Times and USA today
are good newspapers has no connection at
all to why you should watch The Real
World. So what gives?
• Besides, I will show you several reasons
why TRW sucks.
Circular Reasoning
(petitio principi or begging the question)
• Offers as warrants and grounds statements
equivalent to or identical to the claims they
are supposed to support.
Circular
• Mohammed is the messenger of Allah
because Allah caused the Koran to be
written and the Koran says Mohammed is
the messenger of Allah.
• It’s wrong to make animals suffer to further
scientific knowledge because making
animals suffer is clearly wrong.
Refutation of circular reasoning
• When our opponents argue that gaming is
good for Native Americans they offer a
circular argument.
• They tell you this several times but if you
examine the argument they never offer you
any proof.
• They just keep claiming it is good but they
never offer evidence. We prove our claims.
Ad Hominem
• Attacking the person, rather than the
argument.
Ad Hominem
• Ross Perot didn’t know anything about
NAFTA, besides, he had big ears,
• Siskel and Ebert were jerks. I didn’t believe
any of their movie reviews.
Refuting ad hominem
• I don’t disagree with Dieu when she says
that Pete Rose lied about betting on
baseball.
• However, the fact that he is a liar is not
what qualifies him for the hall of fame.
• There are many liars in the hall. The
standard for entry is how well you played.
• Pete was a great player. Period.
False Dichotomy
• Forces listener to choose between
oversimplified either/or options.
False Dichotomy
• Every person is either wholly good or
wholly evil.
• The U.S. must choose to support either
Israel of Palestine.
Refuting a false dichotomy
• Let me tell you where our positions are
different. Manny says we have to make a
choice between conservation and energy
independence. But I think that is wrong.
• Clearly, we don’t have to chose one or the
other. I think that hybrid vehicles prove
that. They show we can try to meet both
goals. There is plenty of middle ground.
Post Hoc Ergo Propter Hoc
(after this then therefore because of this)
• Unwarranted assumption mistaking
temporal succession for causal sequence
Post hoc, etc.
• Its raining because I washed my car
yesterday.
• Every depression followed a Republican
administration.
Refuting Post Hoc
• Saying every war followed a Democratic
administration is about as unreasonable as
saying every depression followed a
Republican administration.
• There are numerous cause for a war, just as
there are numerous causes for depressions.
• Besides, the Viet Nam war followed a
Republican administration.
Fallacies of Appeal
• Appealing to emotion rather than reason
Fallacies of Appeal include:
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Ad ignoratum
Ad populum
Appeal to pity
Appeal to fear
• Appeal to authority
• Appeal to tradition
• Appeal to humor
Ad ignoratum
(appeal to ignorance)
• Asks audience to accept claim solely
because no evidence exists to deny its
validity.
Ignorant
• Since scientists can’t prove global warming
will happen, it probably won’t.
• Nicole Brown’s murderer is still at large
because O.J. hasn’t found him.
Refutation of appeal to ignorance
• In their first claim they say “evolution is an
unproven theory so it is invalid.”
• But think about this for a minute. It’s called
the “THEORY” of evolution. Of course its
not proven.
• However, there are many aspects of the
theory that have been proven so lets look at
some of those. Those aspects are valid.
Ad Populum
• Asks for acceptance of a claim because it is
supported by the majority of the people.
Ad populum
• Most people support the death penalty so it
must be right
• Gore should be president because he won
the popular vote.
Refutation of ad populum
• Certainly, Sam is correct when he says
many people oppose gay marriage.
• However, many people also opposed interracial marriage. Today, that idea is
accepted.
• Something is not necessarily wrong because
many people oppose it. Most people used
to believe the earth was flat.
Appeal to pity
(argumentum ad misercordiam)
• Arousal of sympathy in the place of reason
Pity
• I hope you will accept this late paper. I was
up all night working on it.
• Look how cute this bunny is. How could
someone use it for research?
Refuting appeal to pity
• Eileen says we should give these kids a
break because they are so young.
• That is true. They are young. But the
principles of justice don’t change just
because someone is young.
• If they killed someone, they should pay the
price.
Appeal to Fear
• Arousal of fear in the place of reason
Fear
• If we take the guns from the people only the
criminals will have guns.
• Social Security is once again threatened by
Republicans.
Refuting fear appeals
• The opposing team tells us we needed to
invade Iraq because we were threatened by
weapons of mass destruction.
• This was a an appeal to fear. There is no
evidence of such weapons.
Appeal to authority
(argumentum ad vericundiam)
• Authority in place of reasoning
Authority
• Dr. Fraser Crane recommends the EZ Rest
Hot Tub
• The Rock supported George Bush so he
must have been the best candidate.
Refuting appeal to authority
• The ad shows Tiger Woods driving a Buick.
• I seriously doubt that this is Tiger’s
everyday ride. But, maybe a golfer doesn’t
know that much about cars.
• If I was Tiger I would probably be driving a
Porsche.
Appeal to tradition
• Expresses a customary belief or action
rather than reasoning
Tradition
• Well, that the way we have always done it.
• The Yankees will win the series.
Refuting appeal to tradition
• Fred contends that American cars have
always been superior and so they are now as
well.
• Our position is that there have been many
superior cars world wide both in the past
and today.
• In addition, most of today’s cars are made
with parts produced all over the world.
Appeal to humor
• Reduces another’s claim to its most absurd
conclusion
Humor
• The utilities commission says we need to
raise rates to get people to conserve. Soon,
people will have to refinance to pay their
electric bill.
Refuting appeal to humor
• Sergei claims that if global warming is
accurate we will soon have beachfront
property in Phoenix.
• Not actually. But we can expect an increase
in tides. This will have an affect in the U.S.
• Let’s take a look at how.
Fallacies of language
• The intentional or unintentional use of
language that obscures or confuses the
meaning of an argument.
Fallacies of Language include:
• Ambiguity
• Equivocation
• Emotionally loaded
language
• Technical language
Ambiguity
• Use of a term in a legitimate but different
sense by two or more people involved in an
argument.
Ambiguous
• I enthusiastically recommend this candidate
with no qualifications at all.
Refuting ambiguity
• Let’s be clear.
• We are being told that no candidate would
be better for this job.
• I agree. Having no one would be better
than the candidate being supported by our
opposition.
Equivocation
• Using a term in different ways in the
context of the same argument.
• Don’t take an argumentation course, you are
much too argumentative now.
Refuting equivocation.
• We all know many words have more than
one meaning. I believe my opponent is
using the same term in more than one here.
• That contorts the meaning of the argument.
• Let me restate it for you.
Emotionally loaded language
• Using language that avoids reasoning and
seeks to alter the beliefs or actions of others
through emotion
Loaded
• Once in a generation there is a breakthrough
so revolutionary it can forever change the
way you tan.
• This is a miracle product.
Refuting emotionally loaded language
• Identification theft is a crime as Celina tells
you.
• It is not however,”the most heinous
crime”one could be affected by.
• I would think murder or rape might be
heinous. ID theft is a money crime.
Technical jargon
• Overwhelming an audience with new and
unfamiliar terms in place of reasoning.
Jargon
• Our hedge fund has a great P/E ratio so you
should go big into it.
• The LOC is of unknown duration.
Refuting technical jargon
• The President said “I did not have sexual
relations with that woman.”
• For him, those words may technically be
true.
• For most of us, I don’t think that is the
case.