Announcements
• No class Monday!! ☺
• And we have an awesome quiz #3 on
Tuesday!! ☺
• Prepare for quiz #3 by reviewing last
two homework assignments, today’s
review questions, and Exercises 7-9,
7-10, 7-11
HW Essay #3 Review
Assignment:
• You were asked take note of an advertisement that seems
to be using a fallacy from CH 6 and to identify what fallacy
that is.
• Then, you were asked to make an argument for why you
believe the ad is using the fallacy you think it is using.
Review:
• Need a clear conclusion and clear premise(s).
• To strengthen your premise you should
–
–
–
–
Define your terms (in our case the fallacy you see)
Clearly identify the “issue” – the conclusion the ad makes
Then explain how the conclusion is being supported by rhetoric rather
than reasoning, and that this is indicative of a particular fallacy.
Describe the ad in detail
Review from Last Class
Beyond attacking the source…
7. Straw Man
“Do I want the police department to take charge of writing
parking tickets? You mean, do I want to get shot if I pull up
next to a fire hydrant? What do you think?”
8. False Dilemma
“Are you kidding me? Either we get another department to
write parking tickets or we’ll start getting shot when we pull
up to a fire hydrant.”
Fallacies
Where is the Straw Man Fallacy?
Fallacies
Where is the False Dilemma?
Fallacies
#9. False Dilemma – Special Type: Perfectionist
Believing something is either perfect or must be
rejected.
What’s wrong with this reasoning?
“It’s impossible to eliminate terrorism entirely.
We should stop wasting money on it.”
Can you think of (or make up) others?
Fallacies
#10. False Dilemma – Special Type: Line-Drawing
Believing that either there is a precise place to
draw a line or there is no line to be drawn.
What’s wrong with this reasoning?
“ There shouldn’t be restrictions on violence in
the movies. After all, when is a movie ‘too
violent’? You can’t draw a line.”
Can you think of (or make up) others?
Fallacies
What’s wrong with this argument?
“No, I don’t believe in ‘three strikes and you’re out
for convicted felons. Next thing it will be two
strikes, then one strike. Then we will be sticking
people in jail for life for misdemeanors. It’s not
good policy.”
Issue:
Whether three strikes and you’re out is a good policy.
Conclusion:
No, it’s not.
Premise:
Three strikes and you’re out will lead to jail for life for
misdemeanors.
Fallacies
#11. Slippery Slope
When it is assumed that some event must inevitably
follow from some other event.
“No, I don’t believe in ‘three strikes and you’re out for
convicted felons. Next thing it will be two strikes,
then one strike. Then we will be sticking people in
jail for life for misdemeanors. It’s not good policy.”
Fallacies
Where is the Slippery Slope Fallacy?
Fallacies
What’s wrong with this argument?
Bill: "I think that Mr. Galindo has psychic powers."
Jill: “No way. What’s your proof?
Bill: “Can you prove that he doesn’t have psychic
powers?
Issue:
Whether Mr. Galindo have psychic powers.
Conclusion:
Yes. Mr. Galindo has psychic powers.
Premise:
??
Fallacies
#12. Misplacing the Burden of Proof
When the burden of proof is placed on the wrong side
of an issue.
(The “why not” or “prove it isn’t true” premise.)
So how do we know which side of the issue
has the burden of proof?
Fallacies
So how do we know which side of the issue has
the burden of proof?
1. The side that has less initial plausibility.
Jim: I think I got a raise today because I have an
invisible good luck unicorn living in my bathroom
Kate: What? No way.
Jim: Hey, can you prove that it’s not true?
Fallacies
So how do we know which side of the issue has
the burden of proof?
2. Affirmative side, if all things are equal.
Jane: High school graduates would be
(affirmative) better off going straight to work
rather than going to college.
Marcia: Why?
Jane: Prove that they wouldn’t be (negative)
better off!
Fallacies
So how do we know which side of the issue has
the burden of proof?
3. Special Circumstances (decided at the outset)
Example
Criminal Court “Innocent until proven guilty.”
Fallacies
#13. Misplacing the Burden of Proof – Special
Case: Appeal to Ignorance.
“We should believe it because nobody has proved
it isn’t so.”
Example:
Bill: "I think that Mr. Galindo has psychic powers."
Jill: "What is your proof?"
Bill: "No one has been able to prove that he
doesn’t have psychic powers."
Fallacies
What wrong
with this
argument?
Fallacies
#14. Begging the Question (circular reasoning)
Using premises that already assume the
conclusion is true.
http://www.colbertnation.com/the-colbert-report-videos/405668/january-10-2012/tip-wag--irresponsible-dead-people---insensitive-papa-john-s
https://showyou.com/v/h-9aptNB25Rqx-56wx/tipwag-irresponsible-dead-people-insensitive-papa-johns
Interviewer: "Your resume looks impressive but I
need another reference.“
Bill: "Jill can give me a good reference.“
Interviewer: "Good. But how do I know that Jill is
trustworthy?“
Bill: “That’s easy! I can vouch for her."
Group Exercise
You will be shown a series of “arguments” that
use one of the fallacies we’ve learned in class.
1. Identify the issue.
2. Identify the conclusion.
3. Identify the premise(s) used to support the
conclusion.
4. Indicate which fallacy is being use.
*Note: Some fallacies overlap. For instance straw
man fallacies are similar to false dilemmas, and
both are a type of red herring.
#1 (Ch 7)
“Either we increase the number of troops in Iraq or
the terrorists will be attacking U.S. cities. Seems
like a simple choice to me.”
• Issue: Should we increase the number of
troops in Iraq?
• Conclusion: Yes. We should increase…
• Premise: Because I don’t want terrorists
attacking U.S. cities.
• False Dilemma
#2 (Ch 7)
Jill: "I think the gun control bill shouldn't be
supported because it won't be effective and will
waste money."
Bill: "Well, just last month you supported the bill.
So I guess you're wrong now.“
• Issue: Whether the gun control bill should be
supported.
• Conclusion: Yes, it should be (according to Bill).
• Premise: Because last month Jill supported the
bill, but now she don’t.
• Inconsistency Ad Hominem
#3 (Ch 7)
“Just how much sex has to be in a movie before you
call it pornographic? Seems to me the whole
concept makes no sense.
• Issue: Whether we should label a movie as being
pornographic.
• Conclusion: No, we shouldn’t.
• Premise: Because there’s no clear distinction when a
movie has enough sex to be called pornographic.
• Line-Drawing Fallacy
#4 (Ch 7)
“Twenty percent? You want to tip her 20%? Hey,
next thing you’ll want to tip 25%! And then 30%! It
will never end.”
• Issue: Should we tip her 20%?
• Conclusion: No. We shouldn’t tip her 20%
• Premise: Because I don’t want her tips to be
forever increasing.
• Slippery Slope
#5 (Ch 7)
Jim: The Biblical flood really did wipe out all life on
earth.
Kate: I don’t think it did.
Jim: Hey, can you prove it didn’t???
• Issue: Did the biblical flood wipe out all life on
earth.
• Conclusion: Yes. It did.
• Premise: Because you can’t prove it didn’t.
• Misplaced Burden of Proof
#6 (Ch 7)
“The trouble with impeaching the president is this.
If we start going after him, next we’ll be going after
senators, representatives, governors. Pretty soon,
no elected official will be safe from partisan
attack.”
• Issue: Whether we should impeach the
president.
• Conclusion: No, we should not.
• Premise: Because it will lead to “no elected
officials being safe from partisan attacks.”
• Slippery Slope
#7 (Ch 7)
No, I don’t believe we ought to reinstate the death
penalty in this state. Doing it isn’t going to prevent
all crime, and you know it.
• Issue: Should we reinstate the death penalty.
• Conclusion: No, we shouldn’t.
• Premise: Because doing it isn’t going to prevent
all crime.
• False Dilemma - Perfectionist fallacy.
#8 (Ch 7)
The congressman thought the president’s
behavior was an impeachable offense. But that’s
nonsense, coming from the congressman. He had
an adulterous affair himself, after all.
• Issue: Whether the president’s behavior was an
impeachable offense.
• Conclusion: It is not.
• Premise: Because the congressman, himself, had an
adulterous affair.
• Inconsistency Ad Hominem
#9 (Ch 7)
Your professor wants you to read Moore and
Parker? Forget it. Their book is so far to the right
it’s falling off the shelf.
• Issue: Whether we should read (learn from)
Moore and Parker
• Conclusion: We shouldn’t.
• Premise: Because their book is so far to the
right it’s falling off the shelf.
• Poisoning the well.
#10 (Ch 7)
I don’t think postmodern expressionism is decent
art. It’s another style spawned by the East Coast art
establishment, and, frankly, I’m tired of what that
group is dictating to the rest of the art world.
• Issue: Is postmodern expressionism descent
art?
• Conclusion: No, postmodern expressionism
isn’t…
• Premise: Because I’m tired of what that group’s
dictating to the rest of the art world.
• Genetic Fallacy
#11 (Ch 7)
Don’t tell me I should wear my seat belt, for
heaven’s sake. I’ve seen you ride a motorcycle
without a helmet!
• Issue: Whether I should wear my seat belt.
• Conclusion: No, I shouldn’t have to.
• Premise: Because you ride a motorcycle without
a helmet!
• Inconsistency Ad Hominem
#12 (Ch 7)
“Twenty percent? You want to tip her 20%????
Hey, maybe you want to give her everything we
make, but I frankly think that is ridiculous!”
• Issue: Should we tip her 20%?
• Conclusion: No. We shouldn’t tip her 20%
• Premise: Because I don’t want to give her
everything we make.
• Straw man (though you can make a claim for false
dilemma)
#13 (Ch 7)
Of course you should buy a life insurance policy!
Why shouldn’t you?
• Issue: Whether you should buy a life insurance
policy.
• Conclusion: Yes, you should.
• Premise: Because there’s no reason that you
shouldn’t.
• Misplaced Burden of Proof
#14 (Ch 7)
Of course that can’t be a legitimate proposal. He’s
just trying to get the city council to pass a
regulation that will stir up some business for
himself.
• Issue: Whether it is a legitimate proposal.
• Conclusion: It is not.
• Premise: Because he’s just trying to stir up some
business for himself.
• Ad hominem (circumstantial, presumably).
#15 (Ch 7)
The next speaker is going to speak in favor of the
idea. But she works for the gun lobby. Don’t even
bother listening to what she says. .
• Issue: Whether we should listen to what she
says.
• Conclusion: We shouldn’t listen to….
• Premise: Because she works for the gun lobby.
• Poisoning the well.
#16 (Ch 7)
Outlaw gambling? Man, that’s a strange idea
coming from you. Aren’t you the one who plays the
lottery all the time?
• Issue: Whether we should outlaw gambling.
• Conclusion: No. We should not!
• Premise: Because “you are the one who plays the
lottery all of the time.”
• Inconsistency Ad Hominem
#1 (Ch 6)
I’ll tell you why a hundred dollars is enough child
support. You go into court and ask for more, and I’ll
have my lawyer file a countersuit that will set you
back a bundle in legal fees!
• Issue: Whether a hundred dollars is enough
child support.
• Conclusion: Yes, it is.
• Premise: Because if you ask for more I’ll file a
countersuit and get lots of money from you.
• Scare tactics: Argument by force.
#2 (Ch 6)
Frankly, I don’t think you would be satisfied with
anything less than our Model 24, which allows for
more expansion than any other personal computer
in its class. The way you catch on to things—
something I can tell just from the questions you’ve
asked here in the store—you’re not going to be
happy with a machine whose limits you’ll soon
reach.
• Issue: Whether you’ll be satisfied with anything
less than our Model 24
• Conclusion: No, you wouldn’t be…
• Premise: Because the way you catch on to
things, you’re not going to be happy with less.
• Argument from Pride (apple polishing)
#3 (Ch 6)
Sure, driving after you’ve been drinking can get you
into trouble with the law, but if you’re careful I
don’t think there’s anything wrong with it. After all,
everyone does it, right?
•
•
•
•
Issue: Whether it’s wrong to drink and drive.
Conclusion: No, it’s not wrong…
Premise: Because everyone does it.
Common Practice
#4 (Ch 6)
From a letter to the editor: “They’re wrong again,
the doctors who say that the sun causes cancer.
The four substances for all life are water, food, air,
and sun. Everybody knows the sun opens the pores
of your skin to release poisons; it cannot cause
cancer. Cancer is caused by the toxins man puts in
the air, not by sunlight.”
•
•
•
•
Issue: Whether sun causes cancer.
Conclusion: No, it does not cause cancer.
Premise: Because everybody knows…
Argument from Popularity
#5 (Ch 6)
“It says here that smoke from wood-burning
stoves, no matter how airtight they’re supposed to
be, gets into your house and is a health hazard.”
“No way. We just spent close to a thousand dollars
on this new stove; what you’re reading can’t be
true.”
• Issue: Whether smoke from wood-burning
stoves is a health hazard.
• Conclusion: No way.
• Premise: Because I just spent close to $1000 on
this news stove.
• Wishful Thinking (I’d also accept Rationalizing)
#6 (Ch 6)
Me? I’m going to vote with the company on this one.
After all, I’ve been with them for fifteen years.
• Issue: Whether I should vote with the company
on this one.
• Conclusion: Yes. I should.
• Premise: Because I’ve been with the company
for fifteen years.
• Groupthink fallacy
#7 (Ch 6)
Gays in the military? No way. Clinton promoted the
idea just to get the homosexual vote.
• Issue: Should gays be in the military.
• Conclusion: No they shouldn’t.
• Premise: Because Clinton promoted the idea
just to get the homosexual vote.
• Red Herring
#8 (Ch 6)
Are you telling me that you’re twenty-one years old
and still a virgin? I’d keep quiet about that if I were
you—you’d be the laughingstock of the dorm if
that were widely known.
• Issue: Whether you should still be a virgin at 21.
• Conclusion: No, you shouldn’t be.
• Premise: Because you’ll be a laughing stock.
• Peer Pressure
*If you said the issue was whether to keep quiet,
then would this be a fallacy?