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STUDY GUIDE for

PHILOSOPHY 105:

CRITICAL REASONING

A manual to help you develop your semantic and logical street smarts.

Written and compiled

by Prof. Alan Soble

Note: This Study Guide/Manual is not meant to replace the textbook. (Moore and Parker, Critical

Thinking, 10th

edition.) It is a supplement and complement. Reading the Study Guide/Manual does

not relieve you of the task of reading assigned textbook chapters. They go together.

7th edition, April 2012

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Find a real example of the sort of scholarly writing about which Calvin is talking. Rewrite it, or part of it, so that

it makes better sense. For practice: rewrite the title of Calvin’s book report. Send it to me in an email. Have fun!

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CONTENTS

Notes, Chapters 1 & 2: Introduction to Critical Reasoning; Terminology;

Kinds of “Why?”; Deductive and Inductive Logic …................................... 4

Notes, Chapter 3: Focusing on Types of Ambiguity ………........................ 15

Notes, Chapter 5: Rhetorical Devices #1 ..................................................... 23

Notes, Chapter 6: Rhetorical Devices #2 ..................................................... 30

Notes, Chapter 7: Rhetorical Devices #3 ..................................................... 35

Notes, Chapter 10: More on Induction ........................................................ 39

Puzzle Answers …………………………………………………………… 44

Nota bene: Each of the sections in the Study Guide correspond with (or go with) specific

chapters in the textbook. So the Study Guide chapter "Notes, Chapter 7" is to be studied

along with the textbook chapter 7. Sometime instructions for what to read in the textbook

are included in the Study Guide.

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Notes, Chapters 1 & 2 (and some from Chapter 11)

I. Terminology. Know what these terms mean and be able to provide definitions and

clear examples. (Sources: the textbook chapters; the textbook’s glossary; a good

dictionary; sometimes this manual. Put them all together for a comprehensive definition.)

claim / assertion / statement / belief

argument

premise [part of an argument]

conclusion [ also part of an argument]

relevance of premises to a conclusion

evidentiary relationship [proving or supporting]

deduction [deductive logic]

induction [inductive logic]

II. Subjective statements ["de gustibus non disputandum" and “chacun à son goût”] --

both people who apparently dispute such a claim may be right. — Objective statements:

in some cases, one person is right in a dispute, the other is wrong, even if it is unknown

who is right (they contradict each other); in other cases, both are wrong, but not both

can be right (contraries). See the textbook definitions (p. 5): whether our believing

them influences whether they are true/false.

Think about the difference between "Chocolate ice cream is the best" and "George W.

Bush served two terms, after Bill Clinton." What type of statements are these? Can they

be defended? How, by argument or other evidence? What if someone else says, “No,

vanilla is the best” or “Bush followed Nixon”?

A comic strip that plays with “subjective” and “objective”

III. Be able to tell when an argument is being provided for a claim, and what the content

of that argument is (premises and conclusion). Get in the habit of asking: What evidence

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might be relevant for defending or supporting a claim, and what might be irrelevant, i.e.,

having no or weak impact on whether the claim (or conclusion) is true or false? Also: be

able to distinguish an argument, which has a premise or premises and a conclusion, from

an explanation, which has an explanans and an explanandum (the first explains the

second). Read Chapter 11, pp. 389-92.

What type of claims are moral and aesthetic judgments? Subjective? Objective?

This topic is covered in Chapter 12 of the textbook, if you are curious. (It’s still

covered in Chapter 12, even if you aren’t curious.) You might also take Phil 251

(Ethics) and/or Phil 231 (Aesthetics).

IV. Three kinds of “Why?” question:

1. Why do you believe that? — Asking for the evidence (reasons) that the claim is true.

2. Why did you do that? — Asking for an explanation of your behavior (reasons for

doing it).

3. Why did that happen? — Asking for an explanation of the occurrence of an event.

In asking and answering “Why?” questions, also pay attention to the contrast class. The

question “Why did Adam [in Genesis] eat the apple?” is ambiguous. (We will study

ambiguity in detail in Chapter 3; for now, see textbook, p. 75.) It can mean:

a. “Why did Adam eat the apple?” — as opposed to the male tiger. (Because Adam got to

it first.)

b. “Why did Adam eat the apple?” — as opposed to walking on it. (Because he was

hungry.)

c. “Why did Adam eat the apple?” — as opposed to the pear. (Because pears give him

hives.)

The sort of (correct) answer depends on the point or meaning of “why?”

Definitions of Logic Terms

1. VALID: An argument is valid if and only if it is impossible for all the premises to be

true and the conclusion false. (That’s the “classical” definition.) Or: there is no possible

world in which all the premises are true and the conclusion is false. In an argument

having a valid form, were the premises to be true (which they might not be), the

conclusion would also be true (which it might not in fact be). This subjunctive definition

of validity indicates that the form of a valid argument is truth-preserving (a semantic

concept): in a valid argument, if you start with truth, you end up with truth. In an invalid

argument, it is possible for the premises to be true and the conclusion false (an invalid

argument does not have a truth-preserving form). For an invalid argument, there is at

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least one possible world in which all the premises are true and the conclusion is false.

The truth of the premises does not guarantee that the conclusion is true.

There is a reason why a valid argument is truth-preserving and an invalid

argument is not. In a valid argument, the information in the conclusion is already

contained in the premises. All the conclusion does in a valid argument is to repeat all or

some of the content of the premises. But the conclusion usually presents the information

that is in the premises in a modified, re-arranged way. Such an argument is

“nonampliative.” By contrast, the conclusion of an invalid argument contains

information not found in the premises. An invalid argument is "ampliative," stating more

in the conclusion than what is given in the premises. Hence even if all the premises of an

invalid argument (or any inductive argument) were true, the conclusion would not have to

be true as well, because it has content that goes beyond the content of the premises. The

content and the truth of the conclusion are not "constrained" by the premises.

2. SOUND: An argument is sound if and only if (i) it is valid and (ii) all the premises are

true. By this definition, an unsound argument is one that (1) is invalid or (2) [is valid but]

has at least one false premise. It follows from this definition that the conclusion of a

sound argument is true. An unsound argument might have a true conclusion or a false

one. Note (figure out why) that a valid argument that has a false conclusion must have at

least one false premises.

EXAMPLES of VALID AND INVALID ARGUMENTS

Argument I: All the propositions, the premises and the conclusion, are true and the

argument is valid.

P1. All humans are mortal.

P2. Socrates is human.

C: Socrates is mortal.

Argument II: Everything is false and the argument is still valid (i.e., it displays excellent

logic, i.e., a valid form).

P1. All Lithuanians eat french fries.

P2. Socrates is Lithuanian.

C: Socrates eats french fries.

Why are both argument I and argument II valid? Because, in both cases, were the

premises to be true, it would be impossible to deny the conclusion. Or: if we imagine the

premises to be true, then the conclusion would have to be true. The most accurate way to

make the point is this: both arguments are valid because their form is a valid form: All X

are Y, W is a X; therefore, W is Y. Both arguments I and II have this form.

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Argument III: Everything is true yet the argument is invalid.

P1. I like pizza.

P2. I like lasagna.

P3. I like spaghetti.

C: I like shrimp scampi.

This argument is invalid because, even though all the premises and the conclusion are in

fact true, it is possible that, while the premises are true, the conclusion might be false.

The truth (in fact, or imagined) of the premises does not prevent us from denying the

conclusion. The argument does not manifest a valid form The argument might be a good

induction (see below), but it is an invalid [incorrect] deduction.

Argument IV: The premises are true, the conclusion false, and therefore (by the

definition of "validity") the argument is invalid.

P1. All humans are mortal.

P2. Trigger [the horse] is mortal.

C: Trigger [the horse] is human.

The form of this argument is invalid: All X are Y, W is Y, therefore W is X.

Consider the argument above offered by the penguin. Is it valid? Why or why not?

Is it sound? Why or why not?

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Another exercise in deductive logic (from Raymond Smullyan):

Imagine there is an island inhabited by two types of people, Knights, who always say

what is true, and Knaves, who always say what is false. There are three such people

sitting under a tree: A, B, and C.

A says, "All of us are Knaves."

B says, "Exactly one of us is a Knight."

C says nothing. [This is not the same as: C says "Nothing." What’s the difference?]

What are A, B and C? [For each person, is he/she a Knight or a Knave?]

One procedure to use (there are others): start by assuming someone is a Knight [or a

Knave]. If an assumption leads to a contradiction (internally, or with something you

already know), then that assumption must be false (and its negation true). Eventually you

will find an identification of their types that is consistent (does not lead to any

contradictions). See the end of this Study Guide for the answer.

A similar exercise: On this island, there is a third kind of person, a “normal,” someone

who sometimes tells the truth and sometimes lies. You come across three inhabitants of

this island, lined up in this way: X -- Y -- Z. We know that Tom is a Knight, that

Dick is a Normal, and Harry is a Knave. X says “the guy in the middle, Y, is Tom.” Y

says, “I’m Dick.” Z says, “The guy in the middle, Y, is Harry.” Who’s who?

More Examples: Two Deductively Valid Arguments

I. ABORTION IS MORALLY WRONG

1. The [human] fetus is a human being. [P1]

2. All human beings are persons. [P2]

3. The fetus is a person.

4. All persons have a right to life. [P3]

5. The fetus has a right to life.

6. If a being has a right to life, it is morally wrong to kill it. [P4]

7. It is morally wrong to kill the fetus.

8. Abortion kills the fetus. [P5]

9. [therefore] Abortion is morally wrong. [conclusion]

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II. ABORTION IS MORALLY PERMISSIBLE

1'. The fetus lacks Q. [Even though it is human or a human being.] [P6]

2'. Only those beings that have Q are persons.* [P7]

[Q = consciousness, pain sensitivity, reasoning ability,

communication, self-motivated activity, self-consciousness]

3'. The fetus is not a person.

4'. Only persons have a right to life. [P8]

5'. The fetus does not have a right to life.

6'. If a being has no right to life, it is not morally wrong to kill it. [P9]

7'. It is not morally wrong to kill the fetus.

8'. Abortion kills the fetus. [P5]

9'. [therefore] Abortion is not morally wrong. [conclusion]

*This should more accurately say: only those beings that have a substantial amount of Q

are persons. Pain sensitivity by itself does not guarantee personhood, even if it is likely

necessary for it. Or we could say: those being that possess more of the items in the Q-list,

and those beings that possess the items to a greater extent, are more plausibly persons

than those that possess fewer items or possess the items to a lesser extent.

Question: even though these arguments are valid (have a good deductive form or

evidentiary relationship), are they sound? Are all the premises true? This is

important, because for an argument to be successful, (1) the evidentiary relationship

must be good (which it is, here, in these arguments), but also (2) the premises must

be true. The premises are the claims labeled “P.”

Another Example: THE LOGICAL PROBLEM OF EVIL

Study the logical form of this argument. Decide whether it is valid and, if so, how to

prove the conclusion on the basis of the eight premises. (Try to translate the argument

into a logical language that uses Greek letters; see pp. 10-11 for guidance.) Then think

about the soundness of the argument. Recall that “sound” =df “the argument is valid and

all the premises are true” --- from which definition it follows (validly) that the conclusion

is also true.

1. God exists.

2. God is an omnipotent, omniscient, and perfectly good being.

3. A perfectly good being would want to prevent all evil.

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4. An omniscient being knows every way in which evil can come into

existence.

5. An omnipotent being, who knows every way in which evil can

come into existence, has the power to prevent that evil from

coming into existence.

6. A being who knows every way in which an evil can come into

existence, who is able to prevent that evil from coming into

existence, and who wants to do so, would prevent the existence of

that evil.

7. If there exists an omnipotent, omniscient, and perfectly good

being, then no evil exists.

8. Evil exists.

9. Ergo [the conclusion], either God does not exist OR if God does

exist, God is not omniscient or not omnipotent or not perfectly

good (at least one of those, perhaps two, perhaps all three). Try to

work out the logic of the argument. Pay attention to rule #1,

modus ponens, and rule #2, modus tollens, as well as others.

Now, the “Rules of Inference”: used to construct valid

arguments and to test for validity

1. modus ponens

2. modus tollens f

3. conjunctive addition and simplification

4. disjunctive addition

5. disjunctive syllogism

6. conjunctive syllogism

7. double negation d

8. hypothetical syllogism

9. simple dilemma

10. complex dilemma

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The Greek letters (variables) stand for complete declarative sentences: substitute

some sentences for the variables in each of the rules. For each rule: above the lines =

premises; below = the valid conclusion. What is the point of these “rules of

inference”? Each one is a tiny deductively valid argument. Remember that a valid

deductive argument is nonampliative, that the conclusion contains the information

in the premises but presents it in a re-arranged way. These rules allow you to start

with the premises of a complex argument and re-arrange them (as in algebra or

geometry) until the conclusion “pops out.” That’s the construction of a valid

argument. You should memorize these rules. They all exemplify VALID FORMS.

f

1. If Δ, then λ

Δ a

λ

2. If Δ, then λ

not λ a a

not Δ c f

3. Δ Δ and λ

λ and Δ

Δ and λ (or λ)

4. Δ .

Δ or λ

5. Δ or λ

not Δ d

λ

6. Not both Δ and λ

Δ d

not λ

7. Δ d not not Δ d

not not Δ Δ

8. If Δ, then λ

If λ, then θ f

If Δ, then θ

9. Δ or λ

If Δ, then θ

If λ, then θ d

θ

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10. Δ or λ

If Δ, then θ

If λ, then Φ

θ or Φ

For example, #5, disjunctive syllogism:

P1: I will eat an apple or I will eat a pear. [i.e., at least one of these two fruits]

P2: I will not eat the pear. [I just remembered that I am allergic to pears]

So: I will eat the apple.

(The italicized comments are not part of the argument.)

An example of using more than one rule in the construction of a slightly longer valid

argument (in most deductions, more than one rule is employed):

P1: I will eat an apple or I will eat a pear. [i.e., at least one of these two fruits]

P2: I will not eat the pear. [I just remembered that I am allergic to pears]

So: I will eat the apple. [first intermediate conclusion from P1 and P2 via rule #5]

P3: If I will eat the apple and some grapes, I will be a little more healthy.

P4. I will eat some grapes.

So: I will eat the apple and some grapes. [second intermediate conclusion from P4 and

the first intermediate conclusion via rule #3]

So: I will be a little more healthy. [final conclusion from P3 and the second intermediate

conclusion via rule #1]

Deduction vs. Induction

Deductive arguments intend to establish the certainty of the conclusion on the basis of the

truth of the premises. Inductive arguments intend only to supply evidence (support) that

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the conclusion is probably true. The probability of the conclusion of a valid deductive

argument given that the premises are true is 1. The probability that the conclusion of an

inductive argument is true given the truth of its premises is less than 1. The lower this

probability figure, the weaker the inductive argument. By their nature, all inductive

arguments are deductively invalid – because all inductive arguments are ampliative.

Some inductions are good, so not every deductively invalid argument is worthless.

Whether an inductive argument is strong or weak (and hence whether an invalid

argument taken as an induction is good or bad) depends on the evidentiary relationship

between the premises and the conclusion. Deductive arguments are evaluated as being

either valid or invalid (perfect or imperfect). Inductive arguments are evaluated on a

continuum from strong at one end to weak at the other. “Stronger” and “weaker” are

better terms to use. (Induction is covered in more detail in Chaps. 10 and 11. Browse

ahead.) Another kind of induction, “abduction,” is discussed in the textbook (read pp.

47-48 & Chapter 11, p. 402). This reasoning is also known as “inference to the best

explanation” (IBE).

Examples of inductive arguments follow. Notice how all are deductively invalid (the

arguments are all ampliative).

1. John was absent the first day of class. John was absent the second day of class.

Therefore, John will be absent the next class. [a weak induction.]

2. John was absent the first day of class. John was absent the second day of class. John

was absent the third day of class. John was absent the fourth day of class. John was

absent the fifth day of class. Therefore, John will never show up (maybe he dropped the

class or died). [this might be a strong inductive argument; it is certainly stronger than the

first example.]

2a. Note that this argument is deductively valid: 1. John was absent on day 1. 2. John was

absent on day 2. 3. John was absent on day 3. … N. John was absent on day N. N+1.

There are only N days in this class. Therefore, John was never in class.

3. The Phillies have the best four-pitcher rotation in the major leagues. Howard, Utley,

Victorino, Rollins, and Ruiz are now healthy and starting to hit well. The Phil’s have

overall the best defense in both leagues (they commit the fewest number of errors).

Therefore, the Phils will (probably) win the World Series this year. [You would count

this as a strong induction if you would be willing to bet even money on the conclusion.]

4. John has been absent from class half the semester. He’s not dead (so says his mother).

He’s not in the hospital (there’s only one in our town, and he’s not there). The registrar

says he has not dropped the class. The police say he’s not in jail – his fingerprints are not

in the system. What could explain his absences? He has a demanding job? A demanding

GF? He’s not really absent, but silent and invisible?

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This chart summarizes the important differences between deductive logic/deductive

reasoning and inductive logic/inductive reasoning:

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Notes, Chapter 3: Focusing on Types of Ambiguity

(Which means: study in this chapter the various types of definition mostly on your

own. Indeed, before studying the various types of ambiguities in the textbook and

Study Guide, read pp. 83-87 on definitions. See the end of this part of the Study

Guide for a few words about definitions. )

Language is very useful, of course, but it also presents us with problems, especially when

we take it for granted and don’t think before we speak or write. Here are two cases:

A radio announcer talking about the gathering for the Phillies held in the stadium after

the team had won the World Series in 2008: “Free tickets to the event were up for grabs

yesterday, but sold out in less than 90 minutes.” D’Oh.

Jimmy Rollins, Phillies’ shortstop, trying to make fun of the New York Mets, after the

Phils won the World Series in 2008: “New York was always getting the notoriety – now

it’s our turn.” Right, and the Phils will be notorious in 2011 for having the Best Pitching

Staff Ever in the History of Baseball.

Exercise: figure out what is wrong in each case above. Then restate the mistaken

sentences so that they make (better) sense.

One problem we encounter in the use of language is ambiguity. Here’s one from the

“Frasier” television program: Frasier (at a posh, catered party, spoken to the

protective son of the rich hostess): “I think I should warn you that one of the waiters

is going to hit on your mother for $50K to back a play he has a part in.” The son

replies, “Oh? Which one?” Frasier, “Something by Chekhov, I think.”

What is the ambiguity here? How could it have been avoided? Rewrite the dialogue

to eliminate the ambiguity. NOTE: you can rewrite it in two different ways, one for

each of the possible meanings of the ambiguous element. Be sure not to use the

ambiguous words while rewriting; that only perpetuates the ambiguity.

Another example: “You can count on him.” Rewrites: (1) “You can use his fingers and

toes to do arithmetical problems.” (2) “He is a very reliable person.” Whether what is

really meant, #1 or #2, will depend on the context in which the original sentence is

stated. Of course, the original might be meant as a joke.

Advice: As much as you can, you should provide two rewrites for each ambiguous

sentence, keeping in mind to avoid the ambiguous words or phrases that cause the

original sentence to be ambiguous.

1. VAGUENESS (for similar problems in language, see also “weaseler,” Chapter 5,

and the “line-drawing” fallacy, Chapter 7)

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Vagueness is a lack of precision in an assertion or statement, sometimes meant to deceive

or to be humorous, but sometimes necessitated by the nature of language.

“That’s a pretty big elephant.”

“How big is it?” “You’ll see!”

“Love is a strong emotion.” (How strong is “strong”?)

Vagueness is not the same as ambiguity, which is why we cover it first, to set it aside

(until later, Chapter 5: see “weaseler”). This sentence is ambiguous, but not vague: “I

went to the bank.” It has at least two precise meanings: “I went to my financial

institution,” and “I went to the river bank.”

Try to construct other sentences that are ambiguous but not vague. Notice, too, that

“Love is a strong emotion” is vague but not ambiguous.

2. AMBIGUITY (polysemy) & DISAMBIGUATION

A word that has more than one meaning is ambiguous. A sentence composed of

ambiguous words is therefore also ambiguous, has more than one meaning. There are

several ways this can arise (see types, below). Besides words and sentences, images and

actions can also be ambiguous or polysemous. (Think of examples of ambiguous images

[photographs, drawings, etc.], as well as acts or behaviors that are ambiguous.) When

presented with an ambiguity, we have the task of disambiguating the item (linguistic,

image, act), i.e., clarifying the item to eliminate the ambiguity. We can restate the

assertion using other words, or add information to it, or understand it in its context.

Context is in fact very important. (Note the paradox in trying to disambiguate a linguistic

item, a sentence, by using other linguistic items – which might also be ambiguous. Look

at a book by Stanley Fish, Is There a Text in This Class?) For ambiguity in images, see

the textbook, pp. 45, 155, 159, 217, 237, and elsewhere.

Ambiguous sentence: “I went to the bank and left my paycheck there.”

Disambiguation #1: “I went to my financial institution on 4th

St. and deposited last

week’s wages.”

Disambiguation #2: “While I was walking along the river, I lost my paycheck.”

Ambiguous sentence: “Nothing is better than pizza.”

Disambiguation #1: “Pizza is the most delicious food.”

Disambiguation #2: “Eating nothing is better than eating pizza – it has too much fat.”

3. EQUIVOCATION

Equivocation is relying (intentionally or by accident) on ambiguity to make an argument

appear to be valid when it is actually a case of bad reasoning. A word changes its

meaning during the course of the argument. That’s a logical “no-no.” All words (e.g.,

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when using the rules of inference) must have one and the same meaning all the way

through the argument.

P1 Feathers are light.

P2 What is light is not dark.

CON: Feathers are not dark.

The argument looks valid, seems to have a valid form; but we judge it to be valid only

because we changed the meaning of the word “light” in the second premise.

4. SEMANTIC AMBIGUITY

Sentences that are ambiguous because one or more words in the sentences have more

than one meaning exhibit “semantic ambiguity.”

“Is he on the right side?” The right-hand side of a street, or the correct side of an issue?

“Why did Adam eat the apple?” See page 5, in “Notes for Chapters 1 and 2”; this

question-sentence has at least three meanings and hence three different answers. The

ambiguous element is the word "why."

5. GROUPING AMBIGUITY [Total versus average]

“In the 1990s, guns caused more deaths than nuclear missiles.” Did each gun by itself

kill more people than each missile by itself? Or did all the deaths by guns exceed all the

deaths by the one missile that was launched? The ratio of deaths/gun is greater than the

ration of deaths/missile?

“Professors make more money than street cleaners.” Each professor makes more than

each street cleaner? Or professors as a whole, on average, make more than street cleaners

make, on average? Or the total made by all professors is greater than the total made by all

street cleaners?

6. FALLACIES OF DIVISION/COMPOSITION

Compare “The students in this class are bright” with “This is a bright class of students.”

Can it be true that this is a bright class yet some students are not bright?

All the Phillies players are great players. Does this make the team great?

“Each Eagle player is smart.” Does this mean that the team is smart?

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7. SYNTACTIC AMBIGUITY (Amphiboly)

Ambiguity in a sentence that is due to awkward or misleading grammar; ambiguous

pronouns; oddly-placed prepositional qualifiers, and misplaced modifiers. These

sentences have syntactic (syntax = form or structure) problems. As a result of the

syntactic problem, the sentence becomes semantically ambiguous.

“I want to see a doctor pronto.” (This is better orally.) “I’ll see if we have such a doctor.”

[“Pronto” as a proper noun vs. as an adverb, two different grammatical types.]

“Don’t drink and drive.” [Don’t do both; or don’t drink, but it is OK to drive.]

“I like killing flies.” [“killing” as a verb, what I do to flies; “killing” as an adjective,

what the flies do.]

“I like reading books and empty boxes.” [This one has many interpretations. Make a list.]

“Helicopter powered by human flies.” [The power is provided by “human flies,” an odd

species; a helicopter, powered by humans, flies. “Flies” as a noun vs. as a verb.]

Ambiguous reference of pronouns:

The anthropologists went to a remote area and took photographs of some native

women, but they weren't developed.

Source: Marilyn vos Savant, The Power of Logical Thinking (St. Martin's Press,

1996), p. 76. In this example, the pronoun "they" is ambiguous between the

photographs and the native women.

Misplaced propositional modifier:

One morning I shot an elephant in my pajamas. (Groucho Marx, Animal Crackers)

Amphibolous sign: Are the sheep slippery? Or the roads?

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EXERCISES: In each joke below, what type of ambiguity is employed? Explain the

ambiguity (the various meanings) and how it arises. Rewrite the sentences in

unambiguous ways. Make up your own examples, or find some in newspapers.nes.

“I drew a blank.” (having nothing in mind in answer to a question, or using a pencil)

Grave stone [family name: “Blank”] vs. an empty space.

Female: “I think you’re the father of one of my kids.” Male: [nervously] “Cancun 2002?”

What did the male think the female meant? What else, something different, could she

have meant? Describe the context.

Don’t stop. vs. Don’t. Stop.

“Is your refrigerator running?”

“Do you have Prince Charles in a can?”

I took Mary-Allen through the tunnel, and by 11 P.M. I was asleep on her.

[What or who is “Mary-Ellen?]

“He wished he had found some instructions about communicating in the trash piles.”

(Wall-E, the book, p. 19) [This is amphiboly: found something in the trash vs. about

communicating in the trash = misplaced modifier.]

Katie Couric [on the Letterman show, 3/2/09]: What happened to the 8-10” you promised

me last night? (Said to the morning weathercaster who blew the snow prediction, like

Chevy Chase, the night before.)

Headline: NEW MED SCHOOL DRAWS YOUNG BLOOD

I’d really like a foundation that matches my skin. [What if said at a building site? Or in a

course on epistemology?]

We serve our friends in our house. (vs. buffet-style; or instead of serving [to eat] our

enemies?)

“We don’t serve food here.” (said by the waitperson to a cow sitting at a restaurant table)

“I had a dream last night in which I was playing football with my child.”

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Sarah threatened to kill your brother by email.

Sex between two people is a wonderful thing. [Clearly amphibolous.]

I’m on the radio.

Free toilet paper coupons.

“You are SO grounded, coffee will look at you and say ‘Damn!’” [George Lopez]

Obama likes playing a round of golf. Clinton just liked playing around. [Letterman]

David’s only human. (A full sentence vs. a fragment with a missing but implied subject

and verb.)

In addition to ambiguity, some of the jokes below might exhibit “stereotyping” (see

Chapter 5). In a critical reasoning course (or any philosophy course), we are allowed

to examine as examples all sorts of material, without thereby endorsing them.

A man pushes his BMW into a gas station. He tells the mechanic it

died. After she works on it for a few minutes, the car is idling

smoothly. He asks, “So, what’s the story?” She replies, “Just crap

in the carburetor.” He expresses wonder, and asks: “Oh. How often

do I have to do that?” [This illustrates amphiboly: "crap" as a noun or a verb.]

Highway patrolmen pulled along side a speeding car on the

freeway. Glancing in the window, they were astounded to see that

the woman driving was knitting. Realizing that she didn't notice

their flashing lights and siren, the passenger-seat trooper cranked

down his window, turned on his bullhorn, and yelled at her,

“PULL OVER!” “No,” the woman yelled back, “IT’S A SCARF!”

One night, a guy was playing Trivial Pursuit with his friends. It

was his turn. He rolled the dice and landed on Science & Nature.

His question was, “If you are in a vacuum and someone calls your

name, can you hear it?” He thought for a time and then answered,

“Not if it’s on!” [So much for men and household chores.]

8. Yet another type of ambiguity: Spoonerism Take a look at the article in Wikipedia: it defines “spoonerism” and provides some

information about Reverend William Archibald Spooner, who had a tendency to switch

one or more beginning letters of successive words. One of my favorite examples: “You

21

have hissed all my mystery lectures. You have tasted a whole worm.” Here’s another

(mixed with a pun): “Evidence has been found that William Tell and his family were avid

bowlers. All the Swiss league records were, however, unfortunately destroyed in a fire, so

we’ll never know for whom the Tells bowled.” Also, watch the Muppets’ version of The

Frog Prince. An evil witch has cast a spell on the king’s daughter, so that everything she

says is a spoonerism: “Bake the hall on the candle of her brain.” (If you can solve this

one, you will know how to destroy the witch’s spell.)

Here’s a spoonerism I created for my daughter Rachel:

Maddy and Pachel lunched on brawny dishes, patched some floor rows, and waiter peed a shitty rook.

The solution is at the end of the Study Guide.

9. Yet another type of ambiguity: de re vs. de dicto meanings of a single

sentence

Consider the sentence "Jana wants to marry the tallest man in California." There are two

ways to interpret this sentence.

One interpretation [de dicto] is that Jana wants to marry the tallest man in California,

whoever he might be. On this interpretation, what the statement tells us is that Jana has a

certain specific desire; what she desires is that a certain situation should obtain, namely,

Jana's marrying the tallest man in California. The desire is directed at that situation,

regardless of how it is to be achieved. She might not even know who the tallest man in

California is. She just wants that tall guy, period.

The other interpretation [de re] is that Jana wants to marry a certain man, who in fact just

happens to be the tallest man in California. Her desire is for that man, and she desires

herself to marry him. She is using the expression (perhaps temporarily) “tallest man” to

pick out exactly one person, who is not essentially the tallest man.

The first interpretation, "Jana desires that she marry the tallest man in California," is the

de dicto interpretation. The second interpretation, "Of the tallest man in California, Jana

desires that she marry him," is the de re interpretation.

Another way to understand the distinction is to ask what Jana would want if the man who

was the tallest man in California at the time the original statement was made were to lose

his legs, such that he was no longer the tallest man in California. If she continued to want

to marry that man – and, importantly, perceived this as representing no change in her

desire to marry him – then she could be taken to have meant the original statement in a de

re sense. She wants that man, whether or not he can now be described as the tallest man.

22

If she no longer wanted to marry that man but instead wanted to marry the new tallest

man in California, and saw this as a continuation of her earlier desire, then she meant the

original statement in a de dicto sense. She wants to marry whoever it is at the time who is

the tallest man. (Yes, these things happen.)

EXERCISE: Make up your own sentences that can be de re vs. de dicto ambiguous,

and then provide the two distinct meanings. (Try this one: “I hate my cousin.”)

__________________________________________________________

10. Yet another type of ambiguity: Use vs. Mention

It is standard practice in philosophy to distinguish the use of an expression (words) from

the mentioning of it. Confusing these two is often taken to be a philosophical mortal sin.

Despite its ubiquitous appeal, it is controversial exactly how to draw the distinction. The

initial thought is easy enough. Consider (D1) and (D2):

D1. Jim went to Paris.

D2. “Jim” has three letters.

In (D1) the word “Jim” is used to talk about (or signify, or denote) a person, i.e., Jim, and

the sentence says about that person Jim that he went to Paris. In (D2) the word is not used

in that way. Instead, “Jim” is used to talk about (or signify, denote) a word, i.e., “Jim,”

and the sentence says about that word “Jim” that it has three letters.

In (D1), “Jim” is being used and in (D2) it being mentioned.

Seen on Robot Chicken: “My name is Ludicrous.” “No it isn’t. It’s not even

ridiculous.” “That’s true, it’s not ridiculous, but I swear to you that it’s Ludicrous.”

“Man, don’t be so down on yourself!”

Animaniacs: Skippy and Slappy perform “Who’s on Stage?” (you can find it on

YouTube.com). It’s similar to the Abbott and Costello routine (below).

Person C says “Nothing.” Person C says nothing. (See logic puzzle, page 7.)

LOU: You know the fellows' names? BUD: Yes. LOU: Well, then, who's playin'

first? BUD: Yes. LOU: I mean the fellow's name on first base. BUD: Who. LOU:

The fellow playin' first base for St. Louis. BUD: Who. LOU: The guy on first base.

BUD: Who is on first. LOU: Well what are you askin' me for? BUD: I'm not asking

you---I'm telling you: Who is on first. LOU: I'm asking you---who's on first? BUD:

That's the man's name! LOU: That's who's name? BUD: Yes. LOU: Well go ahead

and tell me. BUD: Who. LOU: The guy on first. BUD: Who. LOU: The first

baseman! BUD: Who is on first! LOU: Have you got a first baseman on first? BUD:

Certainly! LOU: Then who's playing first? BUD: Absolutely! (From their film,

Naughty Nineties [1945].)

23

I’m reading a book by Raymond Smullyan, entitled What Is the Name of This Book?

You ask me, “What’s the name of the book you’re reading?” I reply, What Is the

Name of This Book? You say: “Yeah, that’s what I wanted to know. So, tell me.”

Here’s one that should be read (translated) in Spanish:

Isn’t your name ‘3-PO?’

“C, 3-PO”

“That’s what I thought, ‘3-PO’.”

“Hey! ‘C-3-PO’.”

“Great! ‘3-PO’ it is!”

A few words about definitions: Constructing or using good definitions

can help avoid ambiguity. But not always (maybe hardly always). Study,

in Chapter 3, these various kinds of definition: (A) Categorized by the

purpose of the definition: lexical, precising, stipulative, and persuasive/

rhetorical. (B) Categorized by the type of definition: by providing an

example (ostensive definitions [pointing]), by providing a synonymous

word, or by providing an “analytical” definition.

Notes, Chapter 5: Persuasion through Rhetoric #1

While reading this chapter, pay special attention to the terms listed below in the “List”

(in green). Make sure that you can define these words. They refer to various techniques

of illicit persuasion -- of one person trying to get another person to believe something or

to do something via a fallacious argument, pseudo-argument, or an appeal to emotion.

These are the terms/ideas you will be tested on. (This applies to two later chapters as

well: 6 and 7.)

This chapter will begin to show you why studying critical thinking is important. We live

in a complex world in which people try to influence each other. Rational persuasion,

which relies on sound reasoning (deductive or inductive), is ordinarily taken to be a

respectable procedure for educating and remonstrating with people. The philosopher

Immanuel Kant (Prussia, Konigsberg, 1714-1804) would say that the only way we can

show respect for others, and for ourselves, is by using rational persuasion in our dealings

with them. Although this is not a course in ethics (but ethics is always hovering in the

background), studying critical thinking – and being able to distinguish rational persuasion

from illicit, unfair, tricky, emotional, forms of persuasion -- has an ethical dimension.

It is not only in our best interest to avoid being persuaded to think or do things by other

people who are trying to manipulate us for their own benefit (much advertising and

24

political propaganda is like this), it is also morally suspicious to use illicit techniques on

other people. Of course, sometimes we do it unintentionally, and then we are not

necessarily to blame. Still, one of the goals of this course in critical thinking is to learn

how to avoid both committing and being influenced by specious reasoning. There is a

Catch-22 here. As you learn how to avoid the tricks pulled on you by other people, you

are also learning how to use these tricks on other people. This is why knowledge of

critical thinking can be dangerous knowledge --- like learning how to use a gun: you can

apply this knowledge defensively, but you can also apply it aggressively.

An example of dangerous knowledge: This is a sign taped to the plastic guard covering

the food in a Chinese restaurant buffet. The sign is telling patrons what not to do. But by

telling them what not to do, it is giving patrons ideas which they might never have had. (I

for one, never thought about dipping my fingers in the salad dressing until I read the sign

telling me not to do it.) It is dangerous to tell people not to do things; they might do them

just because you told them not to. (See textbook: p. 49 and Chapter 4, pp. 131-135.)

Buffet Etiquette

DO request a clean plate for second helpings.

DO NOT handle food with your fingers.

DO NOT eat from your plate while standing in the serving line.

DO NOT dip your fingers into the salad dressing.

DO NOT stick your hand under the sneeze guard.

[Does this sound like the Ten Commandments?]

The List

1. euphemism

2. dysphemism

3. stereotype

4. innuendo

5. loaded question

6. sarcasm & other ridicule

7. hyperbole

8. weaseler

9. rhetorical analogy and metaphor [see also pp. 159-162]

10. rhetorical definition [see “begging the question,” in Chapter 7]

The book provides many examples of each of these devices, both in the text itself and in

25

the exercises. There are plenty! Make sure that you know the meaning of these words and

that you can identify when the various forms of suspicious persuasion discussed in the

chapter are being employed. Try to think of examples that go beyond those in the book.

Keep your eyes and ears on the media: there are always good examples of these fallacies

to be found or exposed. Preparing examples of your own at home will help you on the

exams. Guaranteed. Sources to use for definitions (use several at once for a

comprehensive definition): the textbook chapters; the textbook’s glossary; a good

dictionary; sometimes this manual; and pages on the WWW. Be careful about material

you find on the WWW; some of it is very good and some of it is very bad. Read Chapter

4, pp. 127-131.

A note on “weaseler.” Almost every sentence has some vagueness in it. That does not

automatically mean that it is a weaseler. Use the term (and indicate that a device is being

employed) only for gross cases of vagueness. This will be important on exams. I will ask

for the main, significant fallacy or device displayed by a passage. “Weaseler,” because it

is ubiquitous, will rarely be the right answer.

An example of a passage with several devices in it: "Everyone in Professor Jones’s class

should get an A or a B. It's just like a 'basket-weaving' course." (Don’t be concerned with

whether the passage is true or false, but only about the devices the passage uses.) Devices

employed:

1. rhetorical analogy (drawing a specious analogy between the course and a course in

basket weaving)

2. ridicule (describing the course in derogatory terms by linking it with a trivial activity)

3. hyperbole (describing the course in an exaggerated way)

4. stereotype (assuming that all basket-weaving courses are the same, that they are all

silly courses in which nothing is learned and everyone gets an A or B for showing up)

In this example, one passage exhibited four devices. That might happen also in some of

the textbook exercises and on the exams. But many times one and only one device is

most clearly exhibited; you'll need to focus in on that device. We’ll eventually

distinguish between the “focal” device and the “embedded” device (see notes on

Chapter 6).

Note the strong influence of context on meaning and rhetorical force. All sentences

occur (are written or spoken) in a context; to understand a sentence and its rhetorical

force often requires describing and understanding its context in great detail. Here is an

example why, when you provide examples of devices or fallacies (say, on an exam), you

must provide specific details about the background conditions (do not leave it up to

others, including me, to imagine or fill in the details of the context).

For example, consider “Excellent work!”

1. Written at the top of an A paper, a difficult exam: genuine praise.

2. Written at the top of a C paper, an easy exam: sarcastic ridicule.

26

3. Written at the top of a C paper, done by a student who has only done F work so

far: praise, encouragement.

Some Euphemisms and dysphemisms:

Hunter Patch Adams: Death. To die. To expire. To pass on. [To pass.] To perish. To

peg out. To push up daisies. To push up posies. To become extinct. Curtains, deceased,

demised, departed, defunct. Dead as a doornail. Dead as a herring. Dead as a mutton.

Dead as nits. The last breath. Paying a debt to nature. The big sleep. God's way of saying,

"slow down."

Bill Davis: To check out.

Hunter Patch Adams: To shuffle off this mortal coil.

Bill Davis: To head for the happy hunting ground.

Hunter Patch Adams: To blink for an exceptionally long period of time.

Bill Davis: To find oneself without breath.

Hunter Patch Adams: To be the incredible decaying man.

Bill Davis: Worm buffet.

Hunter Patch Adams: Kick the bucket.

Bill Davis: Buy the farm.

Hunter Patch Adams: Take the cab.

Bill Davis: Cash in your chips.

Hunter Patch Adams: And if we bury you ass up, I’ll have a place to park my bike.

Which expressions above (from a Robin Williams movie) are euphemisms and which are

dysphemisms? Can you add more phrases that mean “die”?

Some Rhetorical Tricks in Advertising: In marketing, much money is spent trying to

ensure that a given product is seen as superior to others, or perhaps desirable although

unnecessary. Although the Federal Trade Commission (FTC) regulates and forbids

deceptive marketing practices, advertisers have found new and interesting ways to

convince consumers that their product is superior without outright lying about it. Note the

fine line: deceptive claims are OK, but false claims are not. (Again, see pp. 131-135.)

Weaselers (intentional, manipulative vagueness): Weaselers are words used to soften

the claim, often to make false claims without actually lying. The term comes from the

eating habits of actual weasels. In eating eggs they suck out the inside from a small hole,

leaving the shell nearly intact. Thus weasel claims, while they appear whole, are actually

hollow: they have no content. Commonly used weasel words include comparison words

'like,' 'as much as.' Commonly used qualitative weasel words include 'virtual' or

'virtually,' 'acts' or 'works,' 'can be,' 'up to,' 'tackles,' 'fights,' 'has the feel of,' 'has the look

of' or 'looks like.' Weaselers may also use vague descriptive words, such as 'fortified,'

'enriched,' healthy,' 'natural' or 'strengthened.' Some examples from advertising follow.

27

“Helps control dandruff symptoms with regular use.” The weasels include 'helps control,'

and possibly even 'symptoms' and 'regular use,' both of which are vague. The claim is not

that the product 'stops dandruff.'

“Leaves dishes virtually spotless.” We have seen so many advertising claims that we

have learned to tune out weasels. You are supposed to think 'spotless,' rather than

'virtually spotless.'

“Only half the price of many color sets.” 'Many' is the weasel. The claim is supposed to

give the impression that the set is inexpensive.

“Tests confirm one mouthwash best against mouth odor.”

“Listerine fights bad breath.” 'Fights,' not 'stops.'

“Bacos, the crispy garnish that tastes just like its name.”

“Lips have never looked so luscious.” Can you imagine trying to either prove or disprove

such a claim?

“Its deep rich lather makes hair feel good again.”

“For skin like peaches and cream.”

“The end of meatloaf boredom.”

“Winston tastes good like a cigarette should.”

“The perfect little portable for all around viewing with all the features of higher priced

sets.”

“Fleishman's makes sensible eating delicious.”

Exercises: Which of the rhetorical devices on “The List” are displayed in the

following passages? Explain. (You might spot devices from earlier or later chapters.

Also, the passages below – like some jokes we saw above – contain stereotypes.) Two blondes living in Oklahoma were sitting on a bench talking, and one blonde says to

the other, “Which do you think is farther away…. Florida or the moon?”

The other blonde turns and says, “Helloooooooooo, can you see Florida?”

There’s this blonde out for a walk. She comes to a river and sees another blonde on the

opposite bank. “Yoo-hoo!” she shouts, “How can I get to the other side?”

The second blonde looks up the river and then down the river and shouts back, “You

ARE on the other side.”

28

A real hunk of a guy, a jock-type, but wearing glasses and business suit, carrying a

briefcase, goes into the doctor’s office and said that his body hurt wherever he touched it.

“Impossible!” says the doctor. “Show me.” He took his finger, pushed on his left

shoulder and screamed, then he pushed his elbow and screamed even more. He pushed

his knee and screamed. Likewise he pushed his ankle and screamed. Everywhere he

touched made him scream. The doctor said, “You’re not really an accomplished

businessman, are you?” “Well, no,” said the jock. “I thought so,” the doctor said. “Your

finger is broken.”

An example of a stereotype. Suppose you assert that “Soble is a Jew” and believe, as a

result, that “Soble is cheap.” Someone then asks you for evidence for your conclusion.

Merely repeating that Soble is a Jew is extraordinarily weak and merely perpetuates a

stereotype. If you want to know whether Soble as an individual person is cheap there are

many tests and observations you could make about Soble himself. Does he give to

charities? Or is he stingy with the United Fund? Does he leave a 15-20% tip at

restaurants, or does he lower it to 5-10% if the waitperson brings him decaffeinated

instead of caffeinated coffee? Keep in mind that you will have to adjust your judgments

once you know whether Soble’s income is very high or miserably low. What would be a

cheap tip for a wealthy person would be very generous coming from a poor person.

Another device: QUIBBLING = Using pretentious, pedantic, or

unnecessary precision [vs. vagueness]

quib·ble intransitive verb. quib·bled, quib·bling, quib·bles

1. To evade the truth or importance of an issue by raising trivial distinctions and

objections. (See Red Herring, Chapter 6.)

2. To find fault or criticize for petty reasons; to cavil.

3. Noun = A petty distinction or an irrelevant objection.

Synonyms: quibble, carp, cavil, niggle, nitpick

These verbs mean “to raise petty or frivolous objections or complaints”: quibbling about

minor details; a critic who constantly carped; caviling about the price of coffee; an

editor who niggled about commas; he never tried to stop nitpicking all the time.

Is This an Example of Quibbling? [http://www.usatoday.com/news/special/starr/starr080.htm]

Clinton: Two sets of answers

29

WASHINGTON - In January, President Clinton said Monica Lewinsky was just an intern

who sometimes brought him documents. By August, Clinton's testimony had shifted to

acknowledge "inappropriate intimate contact" with Lewinsky.

Here’s how some of Clinton's answers changed from the January deposition to his

testimony last month:

The Definition of Sex

January 17

Q. So the record is completely clear,

have you ever had sexual relations

with Monica Lewinsky, as that term is

defined ... by the court?

A. I have never had sexual relations

with Monica Lewinsky. I've never had

an affair with her.

Q. She says this, "I have never had a

sexual relationship with the president,

he did not propose that we have a

sexual relationship, he did not offer

me employment or other benefits in

exchange for a sexual relationship, he

did not deny me employment or other

benefits for rejecting a sexual

relationship." Is that a true and

accurate statement as far as you know

it?

A. That is absolutely true.

August 17

Clinton said the two had

"inappropriate intimate contact" but

not sexual relations. He testified that

"any person, reasonable person"

would recognize that oral sex

performed on the person being

questioned "falls outside the

definition" of sexual relations

provided by lawyers for Clinton's

testimony in the Paula Jones case. In

addition, Clinton testified that the

terms "sexual affair," "sexual

relationship" and "sexual relations"

necessarily require sexual intercourse

and that he had not engaged in

intercourse with Lewinsky and

therefore he had not committed

perjury Jan. 17.

Notes, Chapter 6: Rhetorical Devices, #2. Psychological and

Related Fallacies

Chapter 6 deals primarily with fallacies that appeal to our emotions, urges, and drives. It

does not exhaust the possibilities (there are more in Chapter 7). Many cases of specious

reasoning have no standard names, and the number that do have names make up a very

long list. So some cases of faulty reasoning (pseudo-reasoning) do not have to fit one of

the patterns in the textbook or Study Guide. Anyway, I do want you, while reading the

chapter, to focus on the list I provide below of fallacies, devices, and patterns. They are

explained well in the chapter and you can move toward a better understanding of them by

going over the exercises at the back of the chapter. (If you try some exercises for which

the textbook provides no answer, and want to check your work, send me an email, and I

30

will try my luck at it.) Further, many of these fallacies, devices, and patterns are defined

and explained elsewhere in the textbook: see the inside front, the glossary, and the index.

These sources will help you. In a pinch, of course, try a good philosophical dictionary or

browse the WWW (but be careful: much material found on the Internet is garbage).

Pay attention to when a fallacy or device is “focal” and when it is “embedded.” Use

these definitions:

Focal device = the main device/fallacy employed by the passage or argument, or the

main rhetorical purpose of the passage or sentence.

Embedded device = a secondary device/fallacy that the passage uses in order to help

carry out, or relies on in supporting, the focal device.

Some passages might have more than one focal device. You’ll need to be careful to

distinguish passages that have two focal devices from passages that have one focal device

plus one embedded device.

An example:

Son to mother: “You can’t be serious about making me wear these clothes to school.

Do you want me to be a laughingstock? Don’t you know that everyone will snicker?

C’mon, mom, give me a break.”

For all passages, try to refashion them generously so that they have the form of an

argument with premises and a conclusion. In this case, the conclusion is “You should not

make me wear these clothes to school.” The premises (reasons) provided in support of the

conclusion are “If I wear these clothes, I’ll be a laughingstock,” “If I wear these clothes,

everyone will snicker,” “If I am a laughingstock or everyone snickers, that will be bad for

me,” and (implicit) “You shouldn’t do things that are bad for me.”

There are apparently two devices employed in the son’s argument to his mother that she

should not insist that he wear this clothing. One is guilt trip, the other is peer pressure (or

peer-group pressure). The main device, focal, is guilt trip; the son is trying to persuade

his mother by inducing her to feel guilty about her decision. (Guilt-trip argument is best

here, not pity-argument. Induced guilt feelings and induced pity are different.) He is

using the fact that he would experience painful peer-group pressure to generate this guilt

in his mother. So the secondary or embedded device is the peer pressure “argument.”

Any particular device can be focal, and any device can be embedded. The focal is the

main device in the passage or argument; the embedded device is there to help or assist the

focal device. But sometimes there are two devices and they are both focal. Of course, it

will never be the case that there are two devices and they are both embedded.

To study and test yourself on the distinction between focal and embedded devices/

fallacies, hunt carefully for examples on these pages of the textbook: 149, 155, 157, 188,

196, 229, and 379.

31

While reading this chapter, pay attention to the terms listed below in the “List” (in light

blue). Make sure that you can define these words. They refer to various techniques of

illicit persuasion -- of one person trying to get another person to believe something or to

do something via a fallacious argument, pseudo-argument, or an appeal to emotion.

The List

1. scare tactics

2. pity argument

3. guilt trip

4. envy argument

5. scapegoating

6. apple polishing

7. wishful thinking

8. red herring

[plus the four below]

Be careful to keep the following four devices distinct (these are on the “list,” too):

9. peer pressure argument: I will believe X or do Y because all/most/many other people

believe it or do it AND if I don’t, I will be ostracized, made fun of, condemned. [Or I will

not believe or do something because….]

10. popular(ity) argument: a statement is true because all/most/many people believe it

(hence I will believe it, too).

11. common practice argument: a practice (behavior/act) is permissible because

all/most/many people do it (now, in the present) – I’ll do it, too.

12. tradition argument: a statement is true or a practice is permissible because it has

been believed or done for a long time (historical tradition).

A warning: There are cases of legitimate reasoning that bear a resemblance to such

patterns. Don't be too quick to find fallacies where they are not. The book provides

examples of good reasoning, too. Further, I have noticed that some students strain to find

more and more and ... mistakes in various passages. But it is better to uncover one or two

big fat juicy bugs under the rock than a hundred tiny possible bugs that you can barely

see. (Was that hyperbole? Rhetorical metaphor?) Note that you can usually, without

much trouble, find a weaseler, something vague, in a passage. But that is a general

problem in language and does not necessarily indicate the use of device to persuade or

deceive. For each item, try to detect its “fallacy alert signal” — e.g., exaggeration often

involves the word “only,” yet not every case of “only” involves a mistake. When you see

an alert signal, look at the passage closely to determine whether it really does signal a

mistake, and which kind, if it does. The devices and patterns in Chapter 6 often overlap

with each other. Do not be disturbed by this. Try to pick out the mistake that is most

clearly illustrated, and add — stating it as a hunch, perhaps — the other one as well.

(“Focal” versus “embedded” might help here.)

32

Even though devices overlap, notice the clear difference between a “pity”

argument and a “guilt” argument. Pity and guilt are not the same emotion. When you

try to generate pity in another person, you are trying to make them feel sad or

sympathetic toward you (without necessarily trying to make them feel at fault or to blame

for your situation). When you try to generate guilt in another person, you are trying to

make them feel blameworthy, to feel that it is their fault (not yours) that you are in a bad

situation. And you can do this without trying to induce pity in them. Consider the email message below. Is this an appeal to pity, a guilt trip, both, or neither? Explain.

Are there other fallacies or devices in the letter? What would you do, if you were the professor?

“Good afternoon Professor,

I apologize for not emailing my final exam on time. I’m going through a family

crisis with my grandmother. She is in a diabetic comma [sic] right now in Chicago and I

had to drive out there last weekend. To make a long story short the doctors said that she

may have a high chance of brain damage if she recovers or we can basically pull the plug.

My family is in an uproar and is fighting between each other to confirm a decision.

Anyway, I came home this past Sunday to make up two finals this week and I have to

drive back out again tomorrow night. This has been very stressful. I just want to pass this

class and get back to Chicago asap. I know that this paper is late and I know you might

not accept it but I’m hoping that you will. I’m already on academic probation and I can’t

afford to fail any classes. If you choose not to accept this and I fail your class, I thank you

anyway for your time and patience. I enjoyed your class anyway and I did learn a couple

of things. Have a happy holidays. If any questions or comments you can email me back at

this email address. My usual university email is not working!”

Exercise: Which passages below contain a red herring (“beside the point”; “a

different issue”), and committed by which person?

1. ROGER: Harriman is a fraud. He didn’t even graduate from medical school.

ROSCOE: Harriman is still the best surgeon at this clinic.

2. REBECCA: Have you seen those advertisements for striptease dancers for private

parties? That’s exploitative and insulting, if you ask me.

RACHEL: Oh, take it easy. They have male strippers for women’s parties as well as

female strippers for men’s parties.

3. PARTH: Some woman in Tennessee was charged with a felony for not warning

rescuers that her fiancé, who had suffered a heart attack, had tested positive for HIV.

That’s a good law, since people ought to know when they’re stepping into a dangerous

situation to help somebody else.

BART: Well, I don’t think it’s such a good law, because the likelihood of getting HIV

from somebody while trying to resuscitate them is very small.

[Think about this one, #3, for a while. One solution is a few paragraphs below.]

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4. JILL: Experimentation on animals? Horrid, awful, immoral! No argument would justify

experimenting on animals that would not also justify experimenting on humans.

JANE: You’re overlooking all the medical advances that have resulted from

experimenting on animals.

5. Dear Vic: You advertise this lot [on eBay] as "Very nice rare original stamps." No. Not

at all. These are the most common Czech stamps around. Shall I report you to eBay for

blatantly FALSE advertising? – John. [Reply] Dear John: The starting bid is only 99

cents for all the stamps. – Vic

6. From “King of the Hill”

Hank Hill is complaining about his new Laotian neighbor Khan, the man/father in the

family. Hank doesn’t like Khan, because Khan, according to Hank, is “rude and nasty.”

Hank goes out of his way to insist to people that he does not dislike Khan because Khan

is a foreigner or Asian. A friend (the bug exterminator chain-smoker) says to him: “No,

you dislike him exactly because he’s Asian. Just admit it.” Hank: “I wouldn’t care if he

was from Mars.” Friend: “Yes you would. If they were from Mars, they’d be here to

steal all of Earth’s water to take back to their dry planet.”

Back to #3, “Parth and Bart.” Parth defends the law by saying that people should know

when they are stepping into a dangerous situation, which is what the law requires. All

Bart is doing is denying that the HIV situation is a dangerous situation. That leaves the

defense of the law untouched and does not count as a criticism of the law -- it is only a

criticism of applying the law to HIV situations, not of the law itself or in general. Here's

an analogy. Suppose I say "All swans are white," and you deny that. As evidence you

produce an animal that is not a swan. Not a swan = not dangerous -- hence does not fall

within the scope of the law. The non-swan is clearly irrelevant. But that is what Bart is

doing. The best Bart is doing is arguing that there is no need for a law in HIV cases. But

this is far from an argument that the law is no good, period. And Parth was arguing that

the law in general was good. A student in a term over a year ago suggested another

analogy: Would this be similar to Parth arguing that eating blueberries is good for you

and Bart replying with "You don't need to eat fruit."? I answered: Not quite. So, here's

another analogy that is analogous (!) to the analogy I gave before: Parth says, "Eating

vegetables is good for you, for example tomatoes." Bart: "Tomatoes are fruit, not

vegetables." Parth can still say that eating veggies is good for you, while conceding to

Bart that tomatoes, the example used, was not a perfect example. Further, Bart's reply to

Parth says nothing about Parth's claim that veggies are good for you/us.

VICES can also be manipulated by rhetorical persuasion. That is, not only virtues

can be manipulated; e.g., sympathy or kindness by a pity argument. By contrast,

“apple polishing” and the “envy argument” depend on vices.

The seven deadly sins, also known as the capital vices or cardinal sins, are a

classification of vices that were originally used in early Christian teachings to educate

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and instruct followers concerning (immoral) fallen man's tendency to sin. The Roman

Catholic Church divided sin into two principal categories: "venial,” which are relatively

minor, and could be forgiven through any sacrament of the Church, and the more severe

"capital" or "mortal" sins, which, when committed, destroyed the life of grace, and

created the threat of eternal damnation unless either absolved through the sacrament of

confession, or otherwise forgiven through perfect contrition on the part of the penitent.

Beginning in the early 14th century, the popularity of the seven deadly sins as a theme

among European artists of the time eventually helped to ingrain them in many areas of

Christian culture and Christian consciousness in general throughout the world. One

means of such ingraining was the creation of the mnemonic SALIGIA based on the first

letters in Latin of the seven deadly sins: Superbia, Avaritia, Luxuria, Invidia, Gula, Ira,

Acedia.

Listed in the same order used by both Pope Gregory the Great in the 6th Century AD, and

later by Dante Alighieri in his epic poem The Divine Comedy, the seven deadly sins are:

Luxuria (extravagance, later lust), Gula (gluttony), Avaritia (greed), Acedia (sloth), Ira

(wrath, more commonly known as anger), Invidia (envy), and Superbia (pride). Each of

the seven deadly sins has an opposite among the corresponding seven holy virtues

(sometimes also referred to as the contrary virtues). In parallel order to the sins they

oppose, the seven holy virtues are chastity, abstinence, temperance, diligence, patience,

kindness, and humility.

What device is illustrated in the comic below? There is an interesting ambiguity in

the application of this device. Do you see it?

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Notes, Chapter 7: Rhetorical Fallacies & Devices, #3

Whereas the fallacies and devices in Chapter 6 largely depended on manipulating

people psychologically (scaring people with predictions of horrible events; seeking their

pity and sympathy; flattering them), the fallacies discussed in Chapter 7 are largely

“intellectual.” They do not appeal to emotions but try to be legitimate pieces of argument.

This is true even if the “slippery slope” fallacy, for example, does involve, to some

degree, scare tactics and an appeal to our being outraged by possible effects. (Rely on

“focal” vs. “embedded” in this chapter, too. Some of the embedded devices might come

from Chapters 5 and 6.)

The fallacies discussed in Chapter 7 are common and often difficult to detect.

Indeed, the material in Chapter 7 is the most difficult material we have so far

encountered, and it will require diligence and concentration on your part to master the

new fallacies presented and the similarities and/or differences between them. The terms

and fallacies I wish you to pay particular attention to are listed below. (Again, see “The

List.”)

If you try some exercises at the end of Chapter 7 for which the book provides no

answer, and you want to check your work, please send me an email, and I will try my

luck at it. Remember that many of the terms and fallacies are defined and explained

elsewhere in the book: see the inside front cover, the glossary, and the index. These

sources will help you. In a pinch, try a good dictionary or browse the WWW; Wikipedia,

for example, can be helpful, and there are good “critical thinking” web sites on the

internet.

The List

1. Ad hominem personal attack

2. Ad hominem positive

3. Ad hominem circumstantial

4. Ad hominem inconsistency

5. Straw man (straw person)

6. Burden of proof fallacy

7. Argument from ignorance [and see p. 428]

8. False dilemma

9. Line-drawing fallacy

10. Slippery slope

11. Begging the question

A comment about “begging the question.” (The book also makes this point in Chapter

7.) Television advertisements and programs have been, over the last few years, using the

expression “which begs the question.” These ads or programs are using the expression in

a special way that they have invented for their own purposes. What they mean by “which

begs the question” is: what has just been said brings up a question that begs (or demands)

to be answered. That is not how philosophers use the expression. For us it means:

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ASSUMING TO BE TRUE THAT WHICH YOU ARE TRYING TO PROVE IS TRUE.

It is circular reasoning (which gets us nowhere).

Begging the question (from Wikipedia)

In logic, begging the question is the term for a type of fallacy occurring in deductive

reasoning in which the proposition to be proved is assumed implicitly or explicitly in one

of the premises. For an example of this, consider the following argument: "Only an

untrustworthy person would run for office. The fact that politicians are untrustworthy is

proof of this." Such an argument is fallacious, because it relies upon its own proposition

— in this case, "politicians are untrustworthy" — in order to support its central premise.

Essentially, the argument assumes that its central point is already proven, and uses this in

support of itself. Begging the question is also known by its Latin name petitio principii

and is related to the fallacy known as circular argument, circulus in probando, vicious

circle, or circular reasoning. The term is usually not used to describe the broader fallacy

that occurs when the evidence given for a proposition is as much in need of proof as the

proposition itself. The more accepted classification for such arguments is as a fallacy of

many questions.

EXERCISE: Is this begging the question or, perhaps, the “burden of proof” fallacy?

Argument from ignorance? Maybe more than one? (The passage might not say anything at all, while pretending to say something.) It’s a Honda advertisement:

“Can the company of the future create the car of the future? Why not?”

Here is Calvin (below) begging the question:

An example of False Dilemma [from the web site AskPhilosophers.org]

Question: Say I'm in a romantic relationship and I'm trying to decide whether I'd be

happier remaining in it, or leaving it to philander. Of course, experimenting with both

options isn't an option, since I would lose the initial romantic relationship for good. Also,

suppose I really love the person I'm with, and they really love me. Do we have an

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obligation to each other to stay together, since one person choosing to leave would cause

extreme emotional pain to the other? I'm not referring to an ethical obligation, since I'm

aware that there are different moral theories, but an obligation derived purely from the

fact that I love someone. Finally, do I violate either an ethical or other obligation if I

cheat on my romantic partner in order to get a comparison?

Answer: "Whether I'd be happier remaining in it, or leaving it to philander." That's not

the only other option. There are least (1) being alone, seeing if you can be as happy

without him/her as with him/her, or without anyone; and (2) hooking up with another

unattached person and seeing if you are happy with a different person of a different

character. What makes you think you'd enjoy philandering? I take that to mean playing

the field, fishing in many ponds, going out with many people (not necessarily all at once),

having sexual experiences with them (not necessarily all at once). Is this more a quest to

find out what circumstances make you the happiest, or a quest to find out who you are?”

[Is that part of the answer a false dilemma?]

Line-Drawing Fallacy: A concept is dismissed as unclear, meaningless, or inapplicable

because of the inability draw a line to demarcate the edge of the concept. Also called the

Bald Man Fallacy, the Fallacy of the Heap, and the Sorites Fallacy. “Dwayne can never

grow bald.” [That’s the conclusion.] “Dwayne isn't bald now. Don't you agree that if he

loses one hair, that won't make him go from not bald to bald? And if he loses one hair

after that, then this one loss, too, won't make him go from not bald to bald. Therefore, no

matter how much hair he loses, he can't become bald.” We can’t claim that there is a

difference between one extreme and the other (bald vs. full head of hair.) This fallacy

uses false dilemmas in dealing with vague [or “fuzzy”] concepts: If you cannot draw a

line to demarcate the edge of the concept, it is dismissed as hopelessly unclear. “Either

we can identify the precise point at which my eating donuts became excessive, or it was

not excessive. Since we can’t identify the precise point at which it became excessive, it

was not excessive at all.”

Slippery Slope: The conclusion of this type of argument rests on an alleged or assumed

chain reaction and there has been insufficient evidence advanced to support the fact that

such a chain reaction would occur. If the likelihood of the last event (against which we

are being warned) occurring is exaggerated, the slippery slope fallacy is committed. If A

leads to B with a probability of 80 percent, and B leads to C with a probability of 80

percent, and C leads to D with a probability of 80 percent, is it likely that A will

eventually lead to D? No, not at all; there is about a 50-50 chance (.8 x .8 x .8). The

proper analysis of a slippery slope argument depends on sensitivity to such probabilistic

calculations. Note that the final effect in a slope-chain is something horrible, so that scare

tactics are involved here, too.

Two Slopes from Tim Allen (on “Home Improvement”)

Slope #1: 1. Hair (allow kid to have weird hair, e.g., a green Mohawk). 2. Earrings and

other body metal. 3. Tats. 4. Drugs/Sex. 5. Crime. 6. Early Death.

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Slope #2: 1. Holding hands. 2. Kissing. 3. Hugs. 4. Dry humping. 5. Bare bodies. 6. Uh-

oh (early death).

EXERCISE: Is there a “begging the question” in the passage below? This example

is interesting because it leads us into the subject of the next chapter.

From a textbook on science: “What is the scientific method? The scientific method,

which was first systematized by Francis Bacon, involves the identification of a

problem and the rigorous, systematic application of observation and

experimentation in testing an explanation for the problem. How does science differ

from pseudoscience? Pseudoscience is a body of explanation or hypotheses that are

based on emotional appeals, superstition, and rhetoric rather than scientific

observation, reasoning, and testing. Furthermore, unlike scientific hypothesis, those

of pseudoscience are often worded so vaguely as to be untestable. What are some of

the different types of scientific experiments and research methods? Scientific

experiments are carried out under controlled or semicontrolled conditions and

involve systematic measurement and statistical analysis of data. Other research

methods include observation, surveys, and interviews.”

Does the above comic illustrate “begging the question” or “quibbling” or ... ?

Notes, Chapter 10 (and a little on 11): Inductive Reasoning

Advice for understanding whether an inductive (ampliative) argument is

strong or weak: given that the premises are true (and your thinking must be based

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only on the premises, nothing else, unless you make explicit the implicit background

assumptions), would you bet that the conclusion is true? Would you ask for (or

offer) odds? If you would not bet on the conclusion, that indicates that you suspect

that the induction is weak.

Here’s an example: Archie goes with Betty and Veronica to a convention of

parapsychological practitioners. His belief before entering is that the future-

predictors are quacks, shams, phonies, fakes. But, being open-minded and fair, he is

willing to give them a chance to prove him wrong, by conducting what he proposes

is a scientific test of their powers. He says to Betty and Veronica: “I will ask all the

different kinds of artists -- the palm readers, crystal ball gazers, Ouija board

interpreters, mind readers, and Tarot card interpreters -- to predict my future. If

they all agree about what will befall me during the next month, and if I can be

assured that they arrived at their common predictions independently of each other’s

deliberations (i.e., without consulting each other before making their predictions),

then I will take that fact as strongly suggesting that at least some of these

parapsychological techniques may well be reliable after all.”

We should think about such things in a more systematic way. Hence we

proceed to study "inductive" reasoning: trying to predict the unknown (e.g., the

future) from what we already know. Sometimes such reasoning is good, and we

make scientific progress, or win a huge bet. Sometimes the reasoning is terrible, and

we get into trouble, maybe even lose the war. Reading this chapter will help you

develop the skill to construct good inductive arguments and to avoid falling into

certain traps along the way. The concepts I would like you to know from this

chapter are these: INDUCTION (good and bad, or strong and weak), ANALOGY

(good and weak ones; e.g., I have a body and a mind; you have a body; ergo, you

probably have a mind, too;) GENERALIZATIONS (the sun has always risen in the

East, therefore it will rise in the East tomorrow, too); SAMPLE AND TARGET

POPULATIONS; SAMPLES that are REPRESENTATIVE of the TARGET;

SAMPLE SIZE; RANDOM SELECTION OF SUBJECTS. And these problems or

fallacies: HASTY GENERALIZATION (recall stereotyping); ANECDOTAL

FALLACY; AND BIASED GENERALIZATION (= not representative) or

SAMPLING.

Archie thinks that a fair test of the abilities of future-predictors is whether they

independently agree on what will later happen to him. We can discuss his method even

before he uses it: the mere fact that some people agree about X does not by itself provide

excellent reason for thinking that X is true. It might provide some weak reason for taking

their belief in X as reliable or suggestive; after all, if many people agree on X

independently, it is not likely -- although still possible, of course -- that they arrived at X

merely by luck or by coincidence. So there is something to Archie's idea, that the failure

of all to agree means that some of them may be wrong or unreliable, or that if they all

agree this sort of doubt may be tentatively put aside. But that many people agree that X

will occur, even if arrived at separately, does not mean that what they think is true. All

could be wrong. It is easy (do it) to think of examples of many people believing

40

something that turns out to be false. So Archie needs something more than mere

agreement to test the powers of the future-predictors. Here's one way to state the point:

that they all agree may mean that they have reliable powers, but that they all agree is only

one place to start, and we have to go beyond that.

The Xs (predictions) must be stated specifically. This means that Archie should

ask for specific, not vague or ambiguous, predictions, or that Archie should ask specific

questions about his future, and not leave the predictions open-ended (much astrology

suffers from this defect). And he has to do something to make sure that collusion does not

occur, that each practitioner arrives at X on his own. It should not be difficult to satisfy

both these requirements. (But if they have special powers, can’t they collude secretly?)

So, suppose they all agree that X will occur. Archie should not conclude that X

will occur. He must do something else: he must wait to see if X actually happens. [Read

Chapter 11, pp. 393-395.] There is no better test of the predictions than comparing them

to what happens later. Further, this is also what Archie must do if there is disagreement

among the various predictions. If someone predicts X and someone else predicts not-X,

one must be right and the other must be wrong. That they disagree tells Archie nothing

about who is correct. To determine that, he has to wait to see what happens in the future.

So -- the crux -- it doesn't matter whether they all agree or they disagree when making

their predictions. In both cases, the only way to find out if they have the power they claim

to have is to wait to see what actually happens. (This is what scientists routinely do -- try

to predict the future in well-designed experiments.) In this way Archie could take a first

step toward deciding which, if any, of the practitioners have special powers.

Archie must not interfere in any way in what happens later, so that the predictions

can be fairly tested. If I predict X and Archie deliberately acts so as to make X false, then

I was not treated honestly. One way to make sure none of this happens is to have the

predictors write down their predictions and not tell them to Archie. After the events

predicted were supposed to have happened, then Archie can open the sealed envelopes to

see if the predictions came true. Since he had no knowledge of what was predicted, he

could not have interfered with the comparison between the prediction and reality -- unless

he, too, has special powers: being able to read inside sealed envelopes.

Exercises: I. CALVIN

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1. In each of the first three panels, what is Calvin’s explicit argument? State their

premise(s) and conclusions. Note that Calvin uses “means” to indicate his

conclusions and that panel 3 contains 2 arguments.

2. Are these four arguments weak or strong?

3. What are the implicit premises (background information or assumptions) that we

might attribute to Calvin to improve the strength of his inductions? (Do this for

each argument.)

4. Discuss his mother’s statement “Brilliant, Holmes.” [There are two interesting

readings of it, at least.]

5. There is an equivocation in Calvin’s argument (= he uses one word in two

different senses or meanings). Expose the equivocation, and then correct Calvin’s

argument to eliminate the equivocation. Does doing so improve his argument?

2. PSORIASIS DRUG TEST

3. BIASED RESEARCH?

http://daily.stanford.edu/article/2007/5/29/studyResearchExcludesWomenMinorities

Study: Research Excludes Women, Minorities (by Lia Hardin)

Scientific research involving the treatment of alcoholism has disproportionately neglected

women and African Americans, according to a report published last Thursday.

In a journal article examining clinical trials involving more than 100,000 patients,

researchers claimed that academic studies of alcoholism may not reflect the reality that

doctors must confront in clinics.

“Many of the people we see in clinical settings — whether that’s substance abuse or

alcohol treatment — are not being accurately represented in the research literature,” said

study co-author Kenneth Weingardt, a researcher at the Palo Alto Veterans Affairs Health

Care System.

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According to Psychiatry Prof. Keith Humphreys, the study’s lead author, volunteers who

participate in clinical trials must often meet a stringent set of guidelines. This can lead to

the exclusion of members of marginalized groups that are sometimes heavily affected by

the disorder in question.

Humphreys said that patients are often excluded from studies if they do not have

permanent housing or if they have additional medical issues. The fallout of the exclusions

means that many cancer patients are not eligible for cancer studies, nor are many patients

with heart disorders eligible for studies of heart disease, he added.

“[Scientists] often want to exclude patients with any problem other than the one they’re

studying,” Humphreys said.

Scientists conducting clinical research trials must balance the “internal validity” of an

experiment with its external application, explained Weingardt. But according to

Humphreys, many would make a greater effort to include marginalized groups if the

problem were more widely known.

“It’s happened not because of malice but because of lack of information,” Humphreys

said. “So part of the work is doing this and promoting it.”

The results of empirical studies and conditions in clinics are often not closely related in

practice, both researchers explained.

“It takes about 17 years between the time a particular procedure, device or drug is

demonstrated to be effective and when it’s adopted universally across healthcare

systems,” Weingardt said.

He added that reducing that time frame is a major priority for both the National Institutes

of Health (NIH), an institution that funds scientific research, and the Veterans Affairs

Health Care System, which actually delivers patient care.

“For me, personally,” Weingardt said, “I’ve always been very passionate about getting

the research into the hands of the people who can use it to improve care.”

Humphreys agreed that reducing the use of certain biased criteria in forming samples for

clinical trials is important if science is to reflect reality.

“I don’t want to study [a medical disorder] in healthy 25-year-old people who jog and eat

bran muffins,” he said.

4. Longevity and gender

Female: Men live longer if they are married.

Male: No they don’t. It just seems longer.

The question here: if it is true that men who are married (to women) live longer than men

43

who are not married (at all), is it their being married that causes them to live longer? If

not, what is the alternative explanation for the observed correlation?

THIS IS AN IMPORTANT EXAMPLE. TO UNDERSTAND IT, YOU MUST LEARN

THE CONCEPTS “CORRELATION” AND “CAUSE” (causal explanation). THEY

ARE NOT THE SAME THING. SUPPOSE TWO EVENTS OR THINGS ARE

CORRELATED (THEY GO TOGETHER). BY ITSELF THAT DOES NOT MEAN

THAT ONE CAUSES THE OTHER. MAYBE YES, MAYBE NO. IN EACH CASE

YOU’LL NEED TO FIGURE OUT (ON THE BASIS OF OTHER EVIDENCE)

WHETHER ONE CAUSES THE OTHER OR THE OTHER CAUSES THE ONE.

SOMETIMES A THIRD EVENT OR THING CAUSES BOTH OF THE THINGS

THAT ARE CORRELATED. READ CHAPTER 11, pp. 423-428.

Logic puzzle answer (from p. 8):

A, Knave; B, Knight; C, Knave.

Assume B is a Knave. Then it is false that exactly one person is a Knight (because B is a

liar). That means either none is a Knight, or two are Knights, or all three are Knights.

Because we assumed B is a Knave, not all three can be Knights. So the choice is between

none being a Knight ( = all being Knaves) and two being Knights (A and C). If all are

Knaves, including A, then A told the truth, so A must be a Knight. No good: A is both a

Knave and Knight. Impossible. So the only option left is that two are Knights: A and C.

But if A is a Knight, then “all are Knaves,” which A said, is false, and A, as a Knight,

could never say it. Again a contradiction. Hence assuming B is a knave leads to nothing

but contradictions, and must be false.

Now assume, instead, that B is a Knight. Then it is true that exactly one person is a

Knight. That would have to be B himself. So A’s claim, that all persons are Knights, is

false. So A must be a Knave. C, too, must be a Knave, because B told the truth, that there

is exactly one Knight.

--------------------------------

Spoonerism (from p. 18): Daddy and Rachel munched on prawny fishes,

watched some poor shows, and later read a pissy book.

[I didn’t promise to clean it up, but only to re-arrange the starting letters.]