However, this is something beyond my control. I understand that if my
request is granted I will have to put forth extra effort and prepare myself for
the final. With the only other alternative being to drop the course, I am fully
prepared to do whatever it takes.
I have attached a copy of my flight reservation as well as a copy of the
wedding invitation for verification. I am aware that many teachers would not
even give me the opportunity to petition to be excused when the midterm is
the case, but I would more than appreciate it if you would grant my request.
Further Study Descartes' Error. Emotion, Reason, and the Human Brain
by Antonio R. Damasio is a good discussion of how emotions are essential to
good reasoning.
11 Fallacies
A summary of
bad arguments
A. What is a Fallacy? 199
B. Structural Fallacies 199
C. Content Fallacies 201
D. Violating the Principle of Rational Discussion 202
E. Is This Really a Mistake? 202
F. So It's Bad, So What? 203
• Exercises for Chapter 11 204
A. What is a Fallacy?
We've seen lots of bad arguments. Each fits at least one of the conditions for not
repairing an argument (p. 68) or else directly violates the Principle of Rational
Discussion. We labeled a few kinds of these as the sort that typically are
unrepairable.
Fallacy A fallacy is a bad argument of one of the types that have been
agreed to be typically unrepairable.
There are three kinds of fallacy types: structural fallacies, content fallacies, and
violations of the Principle of Rational Discussion. For some fallacy types every
single argument of that type is bad; for others, most, though not all, are bad. Even
taking shortcuts in analyzing arguments requires judgment.
B. Structural Fallacies
Some arguments are bad just because of their form. It doesn't matter if they are
about dogs and cats, or numbers, or truth and beauty. The form alone tells us the
person isn't reasoning well. These are the bad arguments we learned about when
we studied compound claims and general claims. Each, unless there are other claims
as premises, is weak and unrepairable.
199
200 CHAPTER 11 Fallacies
Fallacy type
Similar type of valid
or strong argument
affirming the consequent
direct way of reasoning
If A, then B.
If A, then B.
B
A
Therefore, A.
Therefore, B.
denying the antecedent
indirect way of reasoning
If A, then B.
If A, then B.
not A
not B
Therefore, not B.
Therefore, not A.
arguing backwards with all
direct way of reasoning with all
All S are P.
All S are P.
a is P.
a is S.
Therefore, a is S.
Therefore, a is P.
reasoning in a chain with some
reasoning in a chain with all
Some S are P.
All S are P.
Some P are Q.
All P are Q.
Therefore, some S are Q.
Therefore, all S are Q.
arguing backwards with no
direct way of reasoning with no
All S are P.
All S are P.
No Q is S.
No Q is P.
Therefore, no Q is P.
Therefore, no Q is S.
arguing backwards with almost all
direct way of reasoning with almost all
Almost all S are P.
Almost all S are P.
a is P.
a is S.
Therefore, a is S.
Therefore, a is P.
reasoning in a chain with almost all
Almost all S are P.
Almost all P are Q.
Therefore, almost all S are Q.
When someone presents an argument that fits one of these fallacy types, we
assume he or she is confused about how to reason. We don't try to repair it.
SECTION C Content Fallacies 201
C. Content Fallacies
Many arguments are bad because they use or require for repair a false or dubious
premise. Usually we have to spend some time analyzing the argument, isolating
the dubious premise.
But some arguments look like ones we're always suspicious of. When we spot
one of those, we look for the generic premise the argument uses or needs for repair.
An argument that uses one of these generic premises isn't necessarily bad. Some-
times the premise is plausible or even clearly true. The argument is a fallacy only if
the premise is dubious and no other premises support the conclusion.
• Confusing objective and subjective
This claim is subjective. / This claim is objective.
• Drawing the line
If you can't make this difference precise, there is no difference.
• Mistaking the person {group) for the claim
(Almost) anything that says about is (probably) false.
• Mistaking the person {group) for the argument
(Almost) any argument that gives about is bad.
• Bad appeal to authority
(Almost) anything that says about is (probably) true.
• Bad appeal to common belief {or practice)
If (almost) everyone else (in this group) believes it (or does it),
then it's true (good to do).
• Phony refutation
1. has done or said , which shows that he or she
does not believe the conclusion of his or her own argument.
2. If someone does not believe the conclusion of his or her own
argument, the argument is bad.
• False dilemma
(This is the use of any "or" claim that is false or dubious.
Sometimes an equivalent conditional is used.)
• Slippery slope
(This is reasoning in a chain with conditionals where at least
one of them is false or dubious.)
• Appeal to emotion
You should believe or do because you feel .
(This is always bad if the conclusion is a descriptive claim.)
202 CHAPTER 11 Fallacies
D. Violating the Principle of Rational Discussion
Sometimes it seems the other person doesn't understand what's involved in rational
discussion or is intending to mislead. And sometimes there's not even an argument.
• Begging the question
The point of an argument is to convince that a claim is true. So the
premises of an argument have to be more plausible than the conclusion.
• Strawman
It's easier to knock down someone's argument if you misrepresent it,
putting words in the other person's mouth.
• Shifting the burden of proof
It's easier to ask for a disproof of your claims than to prove them yourself.
• Relevance
Sometimes people say a premise or premises aren't relevant to the
conclusion. But that's not a category of fallacy, just an observation
that the argument is so weak you can't imagine any way to repair it.
There are two other bad ways to try to convince that we've considered.
Though they aren't arguments, and thus aren't fallacies, they're worth not
ing as
violations of the Principle of Rational Discussion.
• Slanters
Concealing claims that are dubious by misleading use of language.
• Ridicule
Making someone or something the butt of a joke in order to convince.
E. Is This Really a Mistake?
SECTION F So It's Bad, So What? 203
This advertisement is an attempt to convince. Its unstated conclusion is "If you plan
to take the LSAT, you should enroll at Kaplan."
It can be seen as a bad appeal to fear, with an unstated premise: "If you are
afraid that your competitors will gain an advantage by enrolling at Kaplan, then you
should enroll at Kaplan."
Or it can be seen as a bad appeal to common practice: "If this is the most
popular way to prepare for the LSAT, and you wish to prepare for the LSAT, then
you should enroll at Kaplan."
Either way the unstated premise is dubious. So the argument is bad. It's a
fallacy no matter which analysis you use.
Often an unstated premise is required to make an argument valid or strong.
And the richness of most arguments will allow for various choices. The argument is
a fallacy only if for each (obvious) choice of premise, the premise is one of the
generic kinds and is clearly false or dubious. There is no reason to believe that a
bad argument is bad in only one way.
Sometimes an argument can be one of the types we call a fallacy while there is
still some more or less obvious premise that will save it. But that's so rare we feel
confident that arguments of the types we've labeled here are normally unrepairable.
The labels you've learned here are like names that go on pigeonholes: This bad
argument can go in here. That argument there. This one fits into perhaps two or
three of the pigeonholes. This argument, no, it doesn't fit into any, so we'll have to
evaluate it from scratch. If you forget the labels, you can still remember the style of
analysis, how to look for what's going wrong. That's what's important.
If you can describe what's wrong, then you understand.
The labels are just shorthand for doing the hard work of
explaining what's bad in an argument.
F. So It's Bad, So What?
You've learned a lot of labels and can manage to make yourself unbearable to your
friends by pointing out the bad arguments they make. That's not the point.
We are seekers of wisdom—or at least we're heading in that direction.
We want to learn, to exchange ideas, not to stifle disagreements. We want to
convince and educate, and to that end we must learn to judge bad arguments.
Some arguments are so bad there's no point trying to repair them. Start over.
Some arguments are bad because the other person intends to mislead you.
In that case the Principle of Rational Discussion is violated. There's no point
continuing the discussion, except perhaps to point out the other person's failings.
These labels and analyses are then prophylactics against being taken in.
204 CHAPTER 11 Fallacies
But often enough the person making the bad argument isn't aware that he or
she has changed the subject or brought in emotions where they don't belong.
Be gentle. Point out the problem. Educate. Ask the other person to fill in the
argument, to add more claims. Then you can, perhaps, learn something, and the
other person can, too.
Key Words fallacy generic premise
structural fallacy violating the Principle of
content fallacy Rational Discussion
Exercises for Chapter 11
The exercises here are a review of this chapter and some of the basic parts of earlier ones.
Your real practice in using this material will come in evaluating the arguments for analysis
that follow in the next section.
1. What are the three tests an argument must pass to be good?
2. State the Guide to Repairing Arguments.
3. State the conditions under which an argument is unrepairable.
4. Is every valid or strong argument with true premises good? Give an explanation and/or
counterexample.
5. If a very strong argument has twelve true premises and one dubious one, should we
accept the conclusion?
6. What does a bad argument tell us about its conclusion?
7. What is our most reliable source of information about the world?
8. Why isn't a slippery slope argument classified as a structural fallacy?
9. Why isn't a false dilemma classified as a structural fallacy?
10. How can we distinguish between ridicule and an attempt to reduce to the absurd?
11. Give an example of affirming the consequent.
12. Give an example of denying the antecedent.
13. Give an example of arguing backwards with "all."
14. Give an example of arguing backwards with "almost all."
15. Give an example of reasoning in a chain with "some." Is it valid?
16. Give an example of arguing backwards with "no."
17. Give an example of confusing objective and subjective. Is it a bad argument?
18. Give an example of drawing the line. Is it a bad argument?
19. Give an example of mistaking the person for the claim. Is it a bad argument?
EXERCISES for Chapter 11 205
20. Give an example of mistaking the person for the argument. Is it a bad argument?
21. Give an example of an appeal to authority that is not a bad argument.
22. Give an example of a phony refutation. Is it a bad argument?
23. Give an example of a false dilemma. Is it a bad argument?
24. Give an example of an appeal to pity. Is it a bad argument?
25. Give an example of an appeal to fear. Is it a bad argument?
26. Give an example of an argument that uses the generic premise of one of the types
of content fallacies but which is not a bad argument.
27. Give an example of begging the question. Is it a bad argument?
28. Give an example of an argument that someone might criticize as having an
irrelevant premise or premises.
29. What is a strawman? Give an example.
30. Why are slanters included in this chapter on fallacies?
Writing Lesson 9
Here is your chance to show that you have all the basic skills to write an argument.
Compose an argument either for or against the following:
Cats should be legally prohibited from roaming freely in cities.
Check whether your instructor has chosen a different topic for this assignment.
This time, write only a (maximum) one-page argument. It should be clear and
well structured, since you will have written out the premises and conclusion for
yourself first. You can recognize slanters and fallacies, so don't use any in your
argument. And you know to include possible objections to your argument.
By now you should have learned a lot about writing arguments. You don't
need more examples, just practice. As a guide you can use the section Composing
Good Arguments on p. 345, which summarizes many of the lessons you've learned.
206
Cartoon Writing Lesson D
For each cartoon write the best argument you can that has as its conclusion
the claim that accompanies the cartoon. List only the premises and conclusion.
If you believe the best argument is only weak, explain why. Refer back to Cartoon
Writing Lesson A on p. 55 for suggestions about how to do this le
sson.
Manuel is in an Olympic race for the handicapped.
Professor Zzzyzzx hit the wasps' nest.
207
208
Cartoon Writing Lesson D
4.
An adult who is not a city employee opened the fire hydrant.
5.
Spot made the boy go away.
6.
The professor is boring.
ARGUMENTS for ANALYSIS
Short Arguments
for Analysis
Here's a chance for you to put together all the ideas and methods of the previous chapters.
Below are 75 short passages you might hear or read any day. Before you start analyzing
them, take a look at how Tom is doing.
Dick: I can't stand Siamese cats. Ugh. They have those strange blue eyes.
Suzy: Mary Ellen has a kitten with blue eyes. I didn't know it was Siamese.
Argument? (yes or no) Yes.
Conclusion (if unstated, add it): Mary Ellen's cat is a Siamese.
Premises: Siamese cats have blue eyes. Mary Ellen's cat has blue eyes.
Additional premises needed to make it valid or strong (if none, say so): None.
Classify (with the additional premises): valid strong X-weak
Good argument? (yes or no, with an explanation—possibly just the name
of a fallacy) No. It's just arguing backwards with "all."
Excell ent!
I hear that Brigitte Bardot is campaigning for animal rights. But she's the one who
used to do advertisements for fur coats.
Argument? (yes or no) Yes—when rewritten.
Conclusion (if unstated, add it): You shouldn't listen to Brigitte Bardot
about animal rights.
Premises: Brigitte Bardot used to do advertisements for fur coats.
Additional premises needed to make it valid or strong (if none, say so):
Don't listen to anything Brigitte Bardot says about fur coats.
Classify (with the additional premises): valid strong X-weak
Good argument? (yes or no, with an explanation—possibly just the name
of a fallacy) No. I think it's mistaking the person for the argument.
At least you spotted that something was wrong. But the premise you added was just
restating the conclusion. 'That would have made it valid all right, But also would
have Seen begging the question.
This is an example of mistaking the person for the claim. Review p. 97.
Richard L Epstein Page 25
