Transcript Fallacies - Lora Lane

Are There Any
Fallacies in the
Reasoning?
CO SCI 58 Asking the Right
Questions
Fallacies
You’ve learned to identify issue and conclusion,
reasons, ambiguities and assumptions. Now
you’re ready to start evaluating the quality of the
reasoning.
A fallacy is a reasoning “trick” that an author uses
while trying to persuade you to accept a
conclusion.
Common Fallacies
Many fallacies are so common they have
been given formal names.
It’s not important to memorize the names,
just to be able to identify that there is a
fallacy.
Ad Hominem
Proving a point by attacking a person or group
rather than ideas. Name-calling is a common
practice.
Sue: The sooner we get out of Afghanistan, the
better. At some point we need to say “enough!”
Our continued concentration on Afghanistan is
hampering our overall effort against terrorism.
Rick: Why is it that you gutless liberals want to
see us surrender to terrorists? We need to fight
until we have won the war.
Ad Hominem
Sue: The sooner we get out of Afghanistan, the
better. At some point we need to say “enough!”
Our continued concentration on Afghanistan is
hampering our overall effort against terrorism.
Rick: Why is it that you gutless liberals want to
see us surrender to terrorists? We need to fight
until we have won the war.
This also demonstrates another type of fallacy
called straw man.
Appeal to Emotion
Authors use words that have an emotional appeal
to sway you. Appeal to pity is the most common
one for Ms. Lane’s class.
Please give me more time for my assignment. My
beloved best friend is so sick and I am worried
to death. I just can’t concentrate on school right
now.
There are Lots of Appeal Fallacies!
Appeal to Authority
 Appeal to Belief
 Appeal to Tradition
 Appeal to Fear
 Appeal to Flattery
 Appeal to Ridicule
 Appeal to Spite … We could go on.

Appeal to Questionable Authority
or Tradition
We’ve always done it this way. Or X is against/for
it so you should be too. Is X a reliable
 Our workers have always been happy working
9-5; there’s no need to change that schedule.
 Wondering about your future? Ask Zena, Beverly
Hills’ own phychic/clairvoyant. Zena has been
sought after and quoted in entertainment
magazines, from TV’s Good Morning America, to
Time. Including the Palm Beach Daily News and
the Palm Beach Post. (Ad from Random
Lengths)
Ad Populum(also called an Appeal to Popularity)
Appeals to group-approved attitudes.
Most Americans agree that…
Everybody knows that….



Americans want to be protected against terrorists. We
must use face recognition systems in public gathering
places.
That’s not fair. All the other kids get to go to the rave!
Everyone knows the governor is unreliable; if we keep
trusting him not to raise taxes, we could all be in debt by
next year.
Equivocation
A key word or phrase is used with two or more meanings in
an argument such that the argument fails to make sense
once the shifts in meaning are recognized.
When Bill Clinton claimed “I never had sex with that
woman,” he was equivocating; the half-truth was that by a
certain very limited definition of “having sex,” he could
say that—but he did not reveal, until pressed, what
definition of “having sex” he was going by.
Slippery Slope
Making the assumption that a proposed step will set off
a chain of undesirable events, when procedures
exist to prevent that sequence of events.
Marijuana should not be legalized for any reason;
medical or otherwise. Legalization would imply that
there are no dangers to drug use. Our children will
get the message that it is okay to experiment with
heroin and designer drugs.
Extension Fallacy
Attacking a position that appears similar to but is
actually different from an opponent’s position. Then
concluding that the opponent’s real position has
been refuted.
I support the idea of one’s choice to have their belly
button pierced. Everybody should have the freedom
to express their uniqueness in a way that they really
enjoy and makes them feel good about themselves.
What is more of a unique way than self-expressing
yourself through body decorations?
Adapted from Ravy Sam’s letter to the Press Telegram.
10-6-02 page A21
Also called straw man
The “straw man” here is the idea of freedom of
expression to refute parental arguments
against belly button piercing.
Parents are usually concerned with health
issues like infections and tearing. They’re not
against self-expression.
Straw Man
Sue: The sooner we get out of Afghanistan, the
better. At some point we need to say “enough!”
Our continued concentration on Afghanistan is
hampering our overall effort against terrorism.
Rick: Why is it that you gutless liberals want to
see us surrender to terrorists? We need to fight
until we have won the war.
Sue says that the overall effort against terrorism
is harmed by the focus on Afghanistan. Does
Rick answer this?
Either 0r Fallacy
Also called a False Dilemma
The writer oversimplifies an issue by stating only
two choices when there are really more.
Watch for:
either ….or…
the only alternative is..
the two choices are…
because A has not worked, only B will…
Example: False Dilemma
The Chinese government is so fierce about
controlling the information dispensed among
its citizenry that it recently shut down
thousands of Internet cafes and blocked
search engines Google and AltaVista.
Chinese citizens deserve to become full
members of the Internet society. American
companies must show support for our values
and refuse to provide Internet services in
China until these gag orders are lifted.
Companies must?
American companies must … refuse to provide
Internet services in China
It’s presented as though there are two black and
white options, no Internet service for the
Chinese people or wide open freedom.
Red Herrings
This fallacy diverts your attention away from the
real issue. The “red herring” is the other issue
he’s using to misdirect you.
Kids are experts
Why didn’t you call me when you didn’t come
home by 11p.m. from your date?
My brother doesn’t have a curfew for dates.
Wishful Thinking
Confusing “What Should Be” and “What Is”
Reality or “what is,” is often in conflict with “what
should be.”
Computer game makers should not be forced to
participate in a rating system. Parents should
review the game content to see if they deem it
appropriate for their child.
Confusing Naming with Explaining
Naming makes us think that we have identified
something that the person has or is that
makes him act accordingly. A different name
for a behavior is presented as the cause of it.
Sony, Panasonic and other electronics
manufacturers are against legislation requiring
recycling fees. It’s big business versus the
earth.
Big business is greedy and bad, earth is good
Perfect Solutions
If a solution doesn’t completely eliminate the
problem, that doesn’t make it bad. It may be
superior to no solution at all.
We should not go through the extra expense of
installing a firewall because hackers will still find
security holes.
Begging the Question
The speaker may put the burden on you to prove
that his conclusion is not correct instead of
giving reasons.
Isn’t is worth $10 a month to protect your home
computer from hackers?
Show me that space aliens don’t exist!
Or he may build on an unproven assumption.
Have you stopped beating your wife?
More Begging the Question
Sometimes the “reason” is just the conclusion
restated in a slightly different way. It’s circular
reasoning.
Internet filtering software should be installed in
schools because undesirable sites will be
blocked.
What Kind of Fallacy is it?
1.
2.
3.
4.
5.
6.
We need to get the latest iPad right away.
Everyone at school has one.
Don’t re-elect President Obama. He is a Marxist
and a racist.
Gays should not be allowed to marry. Marriage
has always been between a man and a woman.
Don’t swim in the ocean. TV star Nicole "Snooki"
Polizzi says "the water's all whale sperm.“
You can stop eating animal products and be
healthy or keep eating them and be unhealthy.
Why should I do my math homework? I don’t
want to be a math teacher.
Answers
1.
2.
3.
4.
5.
6.
Ad populum
Ad hominem
Appeal to tradition
Questionable authority
False dilemma
Red Herring.
End of Lecture