Weak Arguments
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Weak arguments rely on illogical statements
called FALLACIES
The following slides contain examples of
logical fallacies of relevance:
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It focuses attention on the people and not the
argument or the evidence
It attacks the person rather than the issue
E.g. Sam is out of shape how can he be an
effective policeman?
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Winnona Ryder is not a worthless actress
because she was caught shoplifting.
Dr Spock is not an effective second in
command because he has ugly
pointed ears!
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A subcategory of ad hominem
Challenge the motive behind the argument
Question: What will they gain or benefit?
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Another form of the ad hominem fallacy
it often occurs when a person is attacked for
doing what they are arguing against.
Also known as the hypocrisy appeal.
The pot calling the kettle black.
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It is assumed that if one wrong is committed,
another wrong will cancel it out.
This statement is seen as true to some people
due to the fact that 2 negatives indeed make a
positive in math (3-(-3)= 3+3).
However, a person with common sense would
know that two wrongs don't make a right
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Jane: "Did you hear about those terrorists killing
those poor people? That sort of killing is just
wrong."
Sue: "Those terrorists are justified. After all, their
land was taken from them. It is morally right for
them to do what they do."
Jill is horrified by the way the state uses capital
punishment. Bill says that capital punishment is
fine, since those the state kill don't have any
qualms about killing others.
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To reduce complicated issues to simple threats or to
exaggerate a possible danger well beyond its actual
likelihood.
Example: Because of the possibility of a terrorist
hijacking or a mechanical failure, flying on a plane is
too dangerous and should be avoided altogether.
Example: Because of the possibility of poisoning of
Halloween candy by some people who give it out to
trick-or-treaters, communities should ban trick-ortreating.
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Please feel so sorry for me or my cause that you
agree with me.
Gain agreement by sympathy or empathy.
Get the other person to put themselves in your
shoes and see your sorry plight.
Use pictures, testimonies, and other evidence,
all turned to your purpose.
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A genuine instance of the bandwagon fallacy is
the argument that you should vote for a certain
candidate because the majority of people
support that candidate, or the candidate is
popular. This is the origin of the phrase "to
jump on the bandwagon".
Popularity appeal
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Gives false characteristics to an argument and
then attacks the argument based on those false
characteristics.
Just look at
him he
probably
wants to take
all your
money too.
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The argument simply ignores a person’s actual
position and substitutes a distorted,
exaggerated and misrepresented version of the
position.
This guy
wants to
STARVE
our
children!!
The school
lunch budget
must be
examined to cut
down waste
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The straw-man argument attempts to PROVE a
point by over-stating, exaggerating or oversimplifying the arguments of the opposing
side.
Clearly this
guy wants to
bleed
taxpayers dry
with these
increases!!
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It occurs when one changes the subject to draw
attention from the main issue.
The focus is shifted to a side issue or something
irrelevant.
You’re a vegetarian
because you disagree
Abortion and
vegetarianism, are
with killing animals?
2 different subjects
So how can you
that’s how!!!
support abortion
rights?
I work 60 hours a
week to support my
family, and I pay my
taxes; you shouldn’t
arrest me because I
drove a little drunk!
Nice try, but
I recognize a
red herring
when I hear
one!
Why did your
company throw
toxic chemicals
in the river?
You’re not looking at
the big picture. Our
company helps
citizens with jobs and
charity drives. We
even provide college
scholarships for local
students!!
We can’t continue
worrying about
the environment,
we are in the
middle of a WAR!
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The Fallacy of Equivocation occurs when an
equivocal word or phrase makes an unsound
argument appear sound. Consider the
following example:
All banks are beside rivers.
Therefore, the financial institution where I
deposit my money is beside a river.
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Basing an argument on an assumption that has
not been proven or that is impossible to prove.
Argument: People who watch TV are less
active than people who watch no TV.
Unproven Assumption: Because the major
networks broadcast hidden waves to make
people passive and lazy.
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Argument: Evolution should not be taught in
public schools
Unproven Assumption: Because the theory of
evolution comes directly from Satan.
Begging the Question: How do you know the
theory of evolution comes from Satan?
1.
The new Volkswagon Beetle is the coolest car
around. It’s selling like
hotcakes. You should ask your parents to buy you
one.
2. School superintendent Kate Duncan has argued that
children in public schools
should be allowed to participate in a voluntary
moment of silence at the beginning
of each school day. But it’s wrong to allow teachers to
indoctrinate children
with their own religious views. Duncan’s argument
must be firmly rejected.
3. Paper is combustible because it burns.
Al: I can’t believe it! My bank made a mistake on my account
balance.
There’s an extra $3,000 in my checking account.
Joe: Are you going to report the mistake?
Al: Why should I? They’ve been ripping me off for years with
their high
ATM fees.
5. Only man has an immortal soul. No woman is a man.
Therefore, no woman
has an immortal soul.
6. Karen has argued that the secretaries at Acme Steel will get
more respect
if they change their title from “secretary” to “office assistant.”
But everyone
knows that Acme Steel has a bottom-line mentality. They’ll let
you call
yourself anything you want, but they won’t raise your salary a
nickel.
4.
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6.
Bandwagon
Strawman
Begging the question
Two wrongs make a Right
Equivocation
Red Herring
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This fallacy is committed when the person in
question is not a legitimate authority on the
subject.
This sort of reasoning is fallacious when the
person in question is not an expert.
The claim could be true, but the fact that an
unqualified person made the claim does not
provide any rational reason to accept the
claim as true.
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Also known as False Dichotomy
the either-or fallacy (black or white)
It involves a situation in which only two
alternatives are considered, when in fact there
are additional options (sometimes shades of
grey between the extremes).
For example, "It wasn't medicine
that cured Ms. X, so it must
have been a miracle."
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It is a question which contains a
controversial assumption such as a
presumption of guilt
Questioner has an agenda
The traditional example is the question "Have
you stopped beating your wife?" Whether the
respondent answers yes or no, he will admit to
having a wife, and having beaten her at some
time in the past.
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Your father: Did you enjoy spoiling the dinner for
everyone else?
Your mother: Well, I hope you enjoyed making a
fool of me in front of all my friends.
Your boss: Can you begin to appreciate this
wonderful opportunity I'm making available to
you?
Your significant other: Have you finally stopped
flirting with Dana?
Your critical thinking instructor: Aren't you ashamed
about how little effort you've made in this class?
Also known as Post Hoc Fallacy
 Any causal fallacy that involves
an error in a reasoning due to
a failure to adequately investigate
the suspected cause is a fallacy of this type.
Example of Questionable Cause
 Joe gets a chain letter that threatens him with dire
consequences if he breaks the chain. He laughs at it
and throws it in the garbage. On his way to work
he slips and breaks his leg. When he gets back
from the hospital he sends out 200 copies of the
chain letter, hoping to avoid further accidents.
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When investigating a small pond a group
of
graduate students found that there was a
severe drop in the fish population.
Further investigation revealed that the fishes' food supply had
also been severely reduced.
At first the students believed that the lack of food was killing the
fish, but then they realized they had to find what was causing the
decline in the food supply.
The students suspected acid rain was the cause of both the
reduction in the fish population as well as the food supply.
However, the local business council insisted that it was just the
lack of food that caused the reduction in the fish population.
Most of the townspeople agreed with this conclusion since it
seemed pretty obvious that a lack of food would cause fish to die.
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Faulty generalization
based on insufficient evidence
making a hasty conclusion
without considering all of the
variables.
Stereotyping
Misrepresentation of using
small population sample
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Smith, who is from England, decides to attend
graduate school at Ohio State University. He has never
been to the US before. The day after he arrives, he is
walking back from an orientation session and sees two
white (albino) squirrels chasing each other around a
tree. In his next letter home, he tells his family that
American squirrels are white.
Sam is riding her bike in her home town in Maine,
minding her own business. A station wagon comes up
behind her and the driver starts beeping his horn and
then tries to force her off the road. As he goes by, the
driver yells "get on the sidewalk where you belong!"
Sam sees that the car has Ohio plates and concludes
that all Ohio drivers are jerks.
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Bill: "You know, those feminists all hate men."
Joe: "Really?"
Bill: "Yeah. I was in my philosophy class the other day and
that Rachel chick gave a presentation."
Joe: "Which Rachel?"
Bill: "You know her. She's the one that runs that feminist
group over at the Women's Center. She said that men are all
sexist pigs. I asked her why she believed this and she said
that her last few boyfriends were real sexist pigs. "
Joe: "That doesn't sound like a good reason to believe that all
of us are pigs."
Bill: "That was what I said."
Joe: "What did she say?"
Bill: "She said that she had seen enough of men to know we
are all pigs. She obviously hates all men."
Joe: "So you think all feminists are like her?"
Bill: "Sure. They all hate men."
The Slippery Slope is a fallacy in which a person asserts that
some event must inevitably follow from another without any
argument for the inevitability of the event in question
Examples of Slippery Slope
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"We have to stop the tuition increase! The next thing you know,
they'll be charging $40,000 a semester!"
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"The US shouldn't get involved militarily in other countries.
Once the government sends in a few troops, it will then send in
thousands to die."
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"You can never give anyone a break. If you do, they'll walk all
over you."
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"We've got to stop them from banning pornography. Once they
start banning one form of literature, they will never stop. Next
thing you know, they will be burning all the books!"
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Is committed when the arguer uses an analogy to support the
conclusion, but the analogy is inappropriate.
My old car was blue, and had cloth seats. It also got great gas
mileage. I want to get a car with good gas mileage again, so I'm
buying Mike's old Dodge Quad-Cab pickup. It's blue and has
cloth seats.
This fossilized skeleton has a jaw bone similar to that of a horse.
It's teeth are also quite similar, as is the abdominal cavity and feet.
So it was probably a herbivore, like horses are.
Giraffes and gorillas have fur, eat plants, and have names that
start with Gs. They are also very large. Guinea pigs also have a
name that starts with a G, have fur, and eat plants, so they are also
probably very large.
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I’d better eat my Wheaties. Michael Jordan says that it’s the
breakfast of champions.
Ford cars are lemons. I’ve owned two, and they gave me
nothing but trouble.
A Saint Bernard is large, cuddly, furry, and makes a great
house pet. A baby grizzly bear is also large, cuddly, and
furry. Therefore, a baby grizzly bear would make a great
house pet, too.
Everything that exists is animal, or vegetable, or mineral.
The number 7 obviously isn’t an animal or a vegetable.
Therefore, the number 7 is a mineral.
If we don’t dramatically increase defense spending, the
Chinese will soon surpass us as a military power. And, if
the Chinese surpass us as a military power, it’s only a
matter of time before we’ll all be speaking Chinese and
eating chop suey.
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Appeal to Authority
Hasty Generalizations
Weak Analogy
False Alternative
Slippery Slope