shrimp, I got a rash. So I shouldn't eat shellfish anymore.
Argumentl (yes or no) Yes.
Conclusion (if unstated, add it): I shouldn't eat shellfish anymore.
Premises: I got sick after eating shrimp last month. This week again when
I ate shrimp I got a rash.
Additional premises needed to make it valid or strong (if none, say so):
None.
Good argumentl (Choose one and give an explanation.)
• It's good (passes the three tests).
• It's valid or strong, but you don't know if the premises are true,
so you can't say if it's good or bad. Sounds very strong to me.
I sure wouldn't risk eating shrimp again.
• It's bad because it's unrepairable (state which of the reasons apply).
first, a prescriptive claim is needed as premise— seep. 65. Then I agree that I
wouldn't rUkeating shrimp again. "But that doesn't make the argument
strong— there are Cots of other possibilities for why the person got a rash. The
argument is only moderate. 'Risk may determine how strong an argument we 're
witling to accept, but it doesn't affect how strong the argument actually is.
Our congressman voted to give more money to people on welfare. So he doesn't
care about working people.
Argumentl (yes or no) Yes.
Conclusion (if unstated, add it): Our congressman doesn't care about
working people.
Premises: Our congressman voted to give more money to people on
welfare.
Additional premises needed to make it valid or strong (if none, say so):
I can't think of any that are plausible.
Classify (with the additional premises): valid strong X weak
Good argumentl (Choose one and give an explanation.)
• It's good (passes the three tests).
• It's valid or strong, but you don't know if the premises are true,
so you can't say if it's good or bad.
• It's bad because it's unrepairable (state which of the reasons apply).
The only premise I can think of that would even make the argument
strong is something like "Almost anyone who votes to give more
money to people on welfare doesn't care about working people."
And I know that's false. So the argument is unrepairable, right?
'Right! 'Excellent work. You've clearly got the idea. here. I'm sure you can do
more of these now if you'll just remember that sometimes the correct answer is
that the argument is unrepairable. Review those conditions on p. 68.
72 CHAPTER 4 Repairing Arguments
Analyze Exercises 12-34 by answering these questions:
Argument! (yes or no)
Conclusion (if unstated, add it):
Premises:
Additional premises needed to make it valid or strong (if none, say so):
Classify (with the additional premises): valid strong weak
Good argument? (Choose one and give an explanation.)
• It's good (passes the three tests).
• It's valid or strong, but you don't know if the premises are true,
so you can't say if it's good or bad.
• It's bad because it's unrepairable (state which of the reasons apply).
12. Dr. E is a teacher. All teachers are men. So Dr. E is a man.
13. George walks like a duck. George looks like a duck. George quacks like a duck.
So George is a duck.
14. If you're so smart, why aren't you rich?
15. You caught the flu from me? Impossible! I haven't seen you for two months.
16. You caught the flu from me? Impossible! You got sick first.
17. Mary Ellen just bought a Mercedes. So Mary Ellen must be rich.
18. All great teachers are tough graders. So Dr. E is a great teacher.
19. No dog meows. So Spot will only eat canned dog food.
20. No cat barks. So Ralph is not a cat.
21. You're blue-eyed. So your parents must be blue-eyed.
22. Dick: Can you stop at the grocery and buy a big bag of dog food when you're out?
Zoe: You know I'm riding my bike today.
23. Dick: Harry got into college because of affirmative action.
Suzy: Gee, I didn't know that. So Harry isn't very bright.
24. They should fire Professor Zzzyzzx because he has such a bad accent that no one can
understand his lectures in his English literature course.
25. (Advertisement) The bigger the burgers, the better the burgers, the burgers are bigger
at Burger King.
26. Suzy: Did you see how that saleslady treated Harry?
Tom: Yeah, she just ignored him.
Suzy: She must be racist.
27. —That masked man saved us.
—Did you see he has silver bullets in his gunbelt?
—And he called his horse Silver.
—Didn't he call his friend Tonto?
—He must be the Lone Ranger.
EXERCISES for Sections A-D 73
28. These exercises are impossible. How do they expect us to get them right? There are no
right answers! They're driving me crazy.
29. These exercises are difficult but not impossible. Though there may not be a unique
right answer, there are definitely wrong answers. There are generally not unique best
ways to analyze arguments you encounter in your daily life. The best this course can
hope to do is make you think and develop your judgment through these exercises.
30. What!? Me sexually harass her? You've got to be kidding! I never would have asked
her out for a date. Look at her—she's too fat, and besides, she smokes. I'm the boss
here, and I could go out with anyone I want.
31. (From the Associated Press, July 8, 1999, about a suit against tobacco companies for
making "a defective product that causes emphysema, lung cancer, and other illnesses.")
The industry claimed there is no scientific proof that smoking causes any illness and that
the public is well aware that smoking is risky.
32. Flo has always wanted a dog, but she's never been very responsible. She had a fish
once, but it died after a week. She forgot to water her mother's plants, and they died.
She stepped on a neighbor's turtle and killed it.
33. This book will be concerned exclusively with abstract decision theory and will focus on
its logical and philosophical foundations. This does not mean that readers will find
nothing here of practical value. Some of the concepts and methods I will expound are
also found in business school textbooks. Michael Resnik, Choices
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74 CHAPTER 4 Repairing Arguments
Additional Exercises
35. Find a letter to the editor with an argument that depends on at least one unstated premise.
36. Find a letter to the editor with an argument that has an unstated conclusion.
37. a. Make up an argument against the idea that lying is a good way to convince people,
b. Convert your argument in (a) to show that reasoning badly on purpose is not
effective or ethical.
38. Read the Gettysburg Address and explain why it is or is not an argument.
E. Inferring and Implying
Suppose your teacher says in class, "All of my best students hand in extra written
arguments for extra credit." She hasn't actually said you should hand in extra work.
But you infer that she has implied "If you want to do well in this class, you'd better
hand in extra-credit work." The words "imply" and "infer" are not synonyms.
Inferring and implying When someone leaves a conclusion unsaid, he or
she is implying the conclusion. When you decide that an unstated claim is the
conclusion, you are inferring that claim.
We can also say someone is implying a claim if in context it's clear he or
she believes the claim. In that case we infer that the person believes the claim.
Implying and inferring is risky business. If you complain to the department
head that your teacher is demanding more than she asked on the syllabus, your
teacher could reply that you just inferred incorrectly. She might say, "I've observed
that my best students hand in extra-credit work—that's all I was saying. I had no
intention of making an argument." You, however, could say that in the context in
which she made the remark it was fairly obvious she was implying that if you wanted
her to believe you are a good student, you should hand in extra work.
When Suzy was home for vacation, her father said to her before she went out
Saturday night, "Don't forget we're going to be leaving very early for the beach
tomorrow." Suzy got home at 3:30 a.m., and the next morning her father was livid
when she said that she was too tired to help with the driving. "I told you we were
leaving very early," he said. To which Suzy replied, "So?" Her father believes he
clearly implied, "You should get home early and rest enough to help with the
driving." Suzy says he should have been more explicit.
The trouble is, we aren't always explicit; we often leave the conclusion
unstated because it seems so obvious. And what is obvious to you may not be
obvious to someone else. One person's intelligent inference is another's jumping
to conclusions.
EXERCISES for Section E 75
E x a m p l e s What's being implied? What's being inferred?
Example 1 I'm not going to vote, because no matter who is President nothing is
going to get us out of this war.
Analysis An unstated claim is needed to make this into a strong or valid argument:
"If no matter who is President nothing is going to get us out of this war, then you
shouldn't vote for President." We infer this from the person's remarks; he has
implied it.
Example 2 Lee is working in the computer lab at school. He's been there for an
hour and a half. He looks up and notices that all the students who have come in
lately are wearing raincoats and are wet. He figures it must be raining outside.
Analysis We can say that Lee inferred "It is raining outside." But where's the
argument? This is the kind of inferring that psychologists and scientists and lawyers
do all the time. They have evidence, but not stated verbally, and proceed as if they
had an argument.
We often infer from our experience, but we can't analyze those inferences nor
discuss them with others until we have verbalized them into arguments.
Example 3 Lee's teacher makes a sexual innuendo the first day of class. He figures
she must have meant something harmless, and he just didn't get it. But it happens
again. And again. Lee starts taking notes on all the remarks. Finally, after four
weeks Lee is fed up and goes to the head of the department. He says, "My teacher is
making sexually suggestive remarks in class. It's not an accident. It's intentional."
Analysis The argument Lee would need to make to the department head might be
"My teacher made many remarks over a long period of time that could be taken
sexually. This could not be an accident, because it happened too often. Therefore,
she intended to make sexually suggestive comments."
This may or may not be a strong argument, depending on exactly what remarks
were said. It has a subjective claim as a conclusion, one Lee inferred from the
teacher's actions.
Exercises for Section E
1. Suzy says, "I find fat men unattractive, so I won't date you."
a. What has Suzy implied?
b. What can the fellow she's talking to infer?
2. The following conversation is ascribed to W. C. Fields at a formal dinner party. What
can we say he implied?
W. C. Fields: Madame, you are horribly ugly.
Lady: Your behavior is inexcusable. You're drunk.
W. C. Fields: I may be drunk, but tomorrow I'll be sober.
76 CHAPTER 4 Repairing Arguments
3. What can we infer when Dr. E says, "I always keep about 15 pounds extra on me
because I heard that women are intimidated by a man with a perfect body"?
4. In July 2002, the famous race-car driver Al Unser was arrested on allegations by his
girlfriend that very late one night he hit her and forced her out of the car in a deserted
area. His uncle, Bobby Unser, was quoted in the Albuquerque Journal as saying:
What Little Al and Gina Sota did that night was the most nothing thing I've
ever heard o f . . . . He didn't use a gun or a knife or a stick. What's the big deal
about that? This girl is a topless dancer. She's been down that road 100 times.
What can we infer that Bobby Unser believes?
5. [State Senator Manny Aragon] has complained that New Mexico's population is 42
percent Hispanic but the state has no Hispanic representative in Congress.
That sentiment was echoed Thursday by state House Majority Whip James Taylor,
an Albuquerque Democrat, who, like Aragon, represents the South Valley in Bernalillo
County. "It's embarrassing that New Mexico currently has no Hispanic representative in
Congress, especially being a majority-minority state," Taylor said in an interview,
meaning that the sum of all non-Anglo residents is larger than the Anglo population.
"We need to make sure all people of the state are represented."
Associated Press, June 1,2001
What has James Taylor implied?
6. Jean Bottomley, 81, had a radical mastectomy in July and received radiology treatments
for several weeks after that. Bottomley also suffers from macular degeneration, Parkin-
son's disease, and Alzheimer's disease. Unable to drive more than a couple of miles
from her home, Bottomley called the cancer society's local office and requested help.
Albuquerque Tribune, November 14, 2002
What can we infer about Bottomley's driving habits?
7. Give a recent example where you inferred a claim.
Summary Most arguments we encounter are flawed. But they aren't necessarily bad.
They can often be repaired by adding claims that are common knowledge.
By reflecting on the conditions for us to enter into a rational discussion, we can
formulate a guide for how to repair apparently defective arguments. We assume the
other person is knowledgeable about the subject, is able and willing to reason well,
and is not lying. So we add premises that make the argument stronger or valid and
that are plausible to us and to the other person.
Of course, not everyone can reason well, or wishes to reason well. And lots of
arguments can't be repaired, which is something we can discover when we try to add
premises. That, too, helps us evaluate arguments.
Our actions, as well as our words, can lead people to think we believe some
claims. People imply claims by their actions or words, and others infer claims from
them.
EXERCISES for Section E 77
Key Words unstated premise indicator word
unstated conclusion unrepairable argument
The Principle of Rational Discussion irrelevant premise
mark of irrationality imply
suspend judgment infer
The Guide to Repairing Arguments
Further Study To follow up on the idea that rational discussion is necessary for a
democracy, you can read Plato's Gorgias, in which Socrates castigates those who
would convince without good arguments.
An interesting article about the moral and the utilitarian values of reasoning
well, especially for how that may or may not be a "Western" value, is "East and
West: The Reach of Reason," by Amartya Sen in the New York Review of Books,
vol. XLVII, no. 12 (July 20, 2000), pp. 33-38.
A full discussion of rationality, both in terms of arguments and inferring beliefs
from actions, can be found in my Five Ways of Saying 'Therefore', also published
by Wadsworth. That book gives a foundation for all of critical thinking.
Writing Lesson 4
Write an argument in outline form either for or against the following:
No one should receive financial aid their first semester at this school.
• Just list the premises and the conclusion—nothing more.
• Your argument should be at most one page long.
• Check whether your instructor has chosen a different topic for
this assignment.
Remember that with a prescriptive conclusion you need at least one
prescriptive premise that establishes the standard.
Richard L Epstein Page 11
