1. Philosophy 1100 Title: Critical Reasoning Instructor: Paul Dickey
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Today:
Re-submit your Midterm Exam
Final Essay Questions?
Chapter 7 Discussion
Start Chapter 8 (if time permits)
Next Week:
Portfolio Assignment #6
Read Chapter 8, pp ,
pp & pp
Exercises 8-2 & 8-5, 8-16 1 1

2. Portfolio Assignment #6
What is Rhetoric?
·         “Collect” 2-3 artifacts that illustrate different forms of rhetoric. For each, write a description of the artifact selected, identify the form of rhetoric, and explain why this is an example of that particular form.
·   What are Logical Fallacies?
·         “Collect” 2-3 artifacts that illustrate different logical fallacies. For each, write a description of the artifact selected, identify the type of logical fallacy it is, and explain why this is an example of that particular logical fallacy.

3. Chapter Seven
More Fallacies 3 3

4. The Ad Hominem Fallacy Maybe the most common of all logical mistakes.
The Ad Hominem Fallacy mistakes the qualities of the argument itself with the the person or personality of the individual making the claim.
“BOB: Reality consists of more than just what can see and feel. God is real.
BIKER: “If you weren’t so removed from reality, I might be more inclined to discuss it with you.”
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5. The Ad Hominem Fallacy
Most ad hominem arguments are negative and typical examples of ad hominem arguments will be negative, but not always.
e.g. Heather is very nice and is always a very positive person, so if she is opposed to the war in Iraq, there must be something terribly wrong with it.
E.g. Ms. Gullible: “The Jehovah Witnesses that come to the door always seem to be the “sweetest” people so there must be something to what they believe.” 5 5

6. The Personal Attack Ad Hominem
Say you twist the example about Heather around.
e.g. My boss is a very negative person, so although he is opposed to the war in Iraq, that means nothing. He is against everything.
e.g. remember Rush Limbaugh in the video:
“If you are going to start agreeing with Rosie O’Donnell, I would suggest rehab and treatment.” (Ridicule & Sasrcasm)
Video 6 6

7. Specific Forms of Ad Hominems
The Inconsistency Ad Hominem suggests erroneously that if one can show that a person has made contradictory claims at different occasions, then the claims are thereby refuted, e.g. Hilary can’t be right that Obama is ready to be president as she is saying now. She said exactly the opposite during her political campaign.
The Circumstantial Ad Hominem suggests erroneously that if one’s claim is associated to the claimant’s circumstances in life, then the claim is refuted e..g. Of course, Sen. Nelson is for farm subsidies. He is from Nebraska.
Poisoning the Well occurs when an ad hominem is issued prior to allowing someone to make their argument. Interestingly, a speaker might have “the well poisoned against her” by the opponent making a denial of something unsavory about her, such as “Hilary may not be a bleeding heart liberal, but….”
Video 7 7

8. The Genetic Fallacy
The Genetic Fallacy suggests erroneously that a claim is refuted by disputing its origin or history.
e.g. The constitution is a bogus document since it was primarily written with the intent to protect the property of the wealthy.
e.g. God does not exist because the whole idea of God originated with superstitious people who had no knowledge of science or the universe.
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9. The Straw Man or “Straw Figure”
The Straw Man Fallacy occurs when a claim is made that distorts, exaggerates, or otherwise misinterprets an opponent’s position such that it becomes easy to refute.
e.g. “Congressmen who want us to set a timetable to leave Iraq are just saying that we should surrender.”
Important Video
Is this a Straw man Bill Clinton is presenting?
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10. The False Dilemma
The False Dilemma fallacy occurs when you limit considerations to only two alternatives although other alternatives may be available.
e.g. Either we keep all of our current forces in Iraq until victory or we just pull out now unconditionally and let the terrorists win. It is either one or the other, dude.
e.g. You don’t believe in allowing prayer in public schools? So what are you an atheist?
You want this? OR
THIS?
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11. The Perfectionist Fallacy
A specific type of The False Dilemma is the Perfectionist Fallacy which suggests that if a policy or a claim is not perfect then it must be rejected.
e.g. “If they don’t fit, you must acquit.”
Johnny Cochran’s defense of O.J. Simpson, referring to his purported gloves.
e. g. The National Football League’s instant replay rule is no good because you are still going to still have some bad calls.
The National Football League’s instant replay rule is no good because they seem to have to make adjustments to it every year. 11 11

12. The Line-Drawing Fallacy
Another type of The False Dilemma is the Line-Drawing Fallacy which suggests that a distinction cannot be made because there is no precisely known, agreed upon point at which a line can be drawn.
e.g. In the Rodney King case, when exactly did the beatings become excessive force?”
e.g. When did Bill Gates become rich? When he earned his first dollar? His first $100,000? His first $1M? $10M? $1B? Nonetheless, I can assure you that Bill Gates is rich. 12 12

13. The Slippery Slope
The Slippery Slope Fallacy asserts that we can’t let one thing happen because it could lead to something else where there is no argument or a weak argument that the first action does in fact lead to the second.
e.g. Making people register hand guns is just the first step to making guns illegal.
e.g. Marijuana use should be illegal because it can lead to harder drugs.
Important Video
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14. Misplacing/Shifting the Burden of Proof
The burden of proof in an argument rests on the person making the claim. It is her responsibility to give the premises and the reasons to believe her claim is true.
To try to shift the burden of proof onto the person who is listening to your argument and trying to make him show that you are wrong is called misplacing the burden of proof.
A particular example of this logical error is the appeal to ignorance which suggests that we should believe something because no one has proven or shown it to be wrong.
Another example is when a proponent of a claim suggests that his position is right because you haven’t give a good argument for the opposite claim.
Video
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15. (But Mr. Dickey, you said ….)
The Burden of “Proof”?
(But Mr. Dickey, you said ….)
BE VERY CAREFUL!
This terminology is misleading and seems to confuse the issue that we clarified in class earlier about proof and evidence.
Even if you agree to allow someone to say “proof” when they really mean evidence, be sure that you are clear about the difference between the forms of support in deductive and inductive arguments.. 15 15

16. The Top Ten Fallacies of All Time
(according to your author)
“GROPES JAWS”
Group Think
Red Herring
“Argument” From Outrage
“Argument” from Popularity
Post Hoc, Ergo Propter Hoc
Straw Man
Jump to Conclusion
Ad Hominem Argument
Wishful Thinking
Scare Tactic
BREAKING NEWS!
Hominy Strawman outrageously steals jumpsuits, grouping reds with popular pinks. 16 16

17. Chapter Eight Deductive Arguments: Categorical Logic17

18. Categorical Logic Consider the following claims:
1. Everybody who is ineligible for Physics 1A must take Physical Science 1.
2) No students who are required to take Physical Sciences 1 are eligible for Physics 1A.
Are these different claims or the same claim?
Categorical logic is important because it gives us a tool to work through the confusion with a technique to answer that question clearly.
Such is done through the use of standard logic forms. 18

19. Categorical Logic
Categorical Logic is logic based on the relations of inclusion and exclusion among classes.
That is, categorical logic is about things being in and out of groups and what it means to be in or out of one group by being in or out of another group. 19

20. Four Basic Kinds of Claims in
Categorical Logic
(Standard Forms)
A: All _________ are _________.
(Ex. All Presbyterians are Christians.
E: No ________ are _________.
(Ex. No Muslims are Christians.
___________________________________
I: Some ________ are _________.
(Ex. Some Arabs are Christians.
O: Some ________ are not _________.
(Ex. Some Muslims are not Sunnis. 20

21. Four Basic Kinds of Claims in
Categorical Logic
What goes in the blanks are terms. In the first blank, the term is the subject. In the second blank goes the predicate term.
A: All ____S_____ are ____P_____.
(Ex. All Presbyterians are Christians. 21

22. Venn Diagrams 22

23. Categorical Logic
The Four Basic Kinds of Claims in Categorical Logic can be represented using Venn Diagrams.
(See page 256 in textbook.)
The two claims that include one class or part of a class within another are the affirmative claims (I.e. the A-claims & the I-Claims.
The two claims that exclude one class or part of a class from another are the negative claims (I.e. the E-claims and the O-claims. 23

24. Translating Claims into Standard Form for Analysis
The Bottom Line?
Translating Claims into Standard Form for Analysis
Two claims are equivalent claims if, and only if, they would be true in all and exactly the same circumstances.
Equivalent claims, in this sense, say the same thing.
Equivalent claims will have the same Venn Diagram. 24

25. Some Tips
The word “only” used by itself, introduces the predicate term of an A-claim, e.g.
“Only Matinees are half-price shows” is to be translated as “All half-price shows are matinees”
The phrase “the only” introduces the subject term of an A-claim, e.g
Matinees are the only half-price shows” also translates to “All half-price shows are matinees.”
Claims about single individuals should be treated as A-claims or E-claims, e.g.
“Aristotle is left-handed” translates to either “Everybody who is Aristotle is left handed” or “No person who is Aristotle is not left-handed.” 25

26. Class Workshop:
Exercise 8-1 26