1. Informal Fallacies(Ch. 8)

2. Informal Fallacies
Valid arguments (modus ponens, chain argument): invalid argument
Strong non-deductive arguments; weak arguments
An IDEAL rational discussion/debate
Person A makes an argument for x.
Good response: Person B responds by evaluating the argument
argument is strong/weak
Its premises are true or false.
Informal Fallacies committed when a debate does not go ideally

3. Personal Attacks 1
Chapter 8

4. Personal Attack Fallacies
Person A makes an argument for x.
Person B attacks the person instead of considering the argument
Abusive Ad Hominem: person B attacks A’s character
Attacking the Motive: person B attacks A’s motive for making the argument
Tu Quoque: person B attacks A’s hypocrisy
Genetic (Origin) Fallacy: person B attacks A as a bad source of information

5. Abusive Ad Hominem Respondent attacks arguer’s character Example:
Donald Trump has been reported to be a cheater and a womanizer. Clearly, his economic policies are not going to help anyone.
Good “Personal Attacks” :
Millions of innocent people died in Stalin’s ruthless ideological purges. Clearly, Stalin was one of the most brutal dictators of the twentieth century.
Becky Fibber has testified that she saw my client rob the First National Bank. But Ms. Fibber has twice been convicted of perjury. In addition, you’ve heard Ms. Fibber’s own mother testify that she is a pathological liar. Therefore, you should not believe Ms. Fibber’s testimony against my client. [Issue: is Ms. Fibber is a credible witness?]

6. Attacking the Motive
Attacking the Motive: person B attacks A’s motive for making the argument rather than examining the argument itself
Example: Don’t listen to what Julia Greenberg says about continued rent controls. No wonder she wants to end them. She owns an apartment building and stands to gain much profit if rent controls are terminated. So, her claim that rent controls should be abandoned must be rejected.
Example: The Bush Administration had everything to gain from going to war with Iraq. Vice president Chaney military company stands to gain enormous profits as does Bush’s investments in oil. Clearly, their justification for going to war are wrong.

7. Tu Quoque: “Look who’s talking” fallacy
Tu Quoque (“kwokway”): person B attacks A’s hypocrisy
“You should stop smoking, because there is a higher chance of getting heart disease later in life as well as lung cancer.” says the father while smoking a cigar.
Reply: You make no sense. You argue against smoking while smoking.
Good criticisms of hypocrisy
Jim: Our neighbor Joe gave me a hard time again yesterday about washing our car during this drought emergency.
Patty: Well, he’s right. But I wish that hypocrite would live up to his own advice. Just last week I saw him watering his lawn in the middle of the afternoon.

8. Genetic Fallacy
Genetic Fallacy: source of a claim or argument is judged to be defective, and so, any argument that comes from that sources should be rejected.
John, gives an argument that abortion is morally wrong. Person B (respondent) objects that the argument came from a man.
Assumption: John cannot have children or be in a position to choose to have an abortion, so he is not a good source on this issue (no matter what argument he actually gave). So, we should reject his argument.

9. Appeals to Authority 2
Chapter 8

10. Good Appeals to Authority
Expert Witness
expert witness at trial
Expert in a Field
meteorologist about weather
Scientist on established scientific opinions
Issue: what about scientific issues that are not settled yet?

11. Fallacies by Appeal to Authority
Appeal to the One
Appeal to the Many
Appeal to the Few (Elite)
Appeal to Tradition/Custom

12. Diversionary Tactics 3
Chapter 8

13. Straw Man Fallacy
Straw-Man Fallacy: an arguer distorts an opponent’s argument or claim to make it easier to attack.
Senator Biddle has argued that we should outlaw violent pornography. Obviously, the senator favors complete governmental censorship of books, magazines, and films. Frankly, I’m shocked that such a view should be expressed on the floor of the U.S. Senate. It runs counter to everything this great nation stands for. No senator should listen seriously to such a proposal.

14. Red Herring Fallacy
The red herring fallacy is committed when an arguer tries to sidetrack his audience by raising an irrelevant issue and then claims that the original issue has effectively been settled by the irrelevant diversion.
Many people criticize Thomas Jefferson for being an owner of slaves. But Jefferson was one of our greatest presidents, and his Declaration of Independence is one of the most eloquent pleas for freedom and democracy ever written. Clearly, these criticisms are unwarranted.

15. Straw Man vs. Red-Herring Fallacy
The straw man fallacy always involves misrepresenting another person’s argument or claim; the red herring fallacy often does not.
Straw man but not Red herring fallacy:
I overheard my friend Hal say that democracy isn’t always the best form of government. Funny, I never figured Hal for a communist.
Red herring but not Straw man fallacy:
Jessica Wu has argued that immediate steps should be taken to reduce global warming. The most serious environmental problem, however, isn’t global warming—it’s overpopulation. Unless something is done to reduce population growth in the third world, mass starvation and irreversible environmental damage will result. Frankly, I think Jessica’s view is ridiculous.

16. Emotional Appeals 4
Chapter 8

17. Fallacies by Appeal to Pity
Examples: The missed homework assignment because of a rough hangover.
Good Appeals to Pity:
Mother to daughter: Nana was asking about you the other day. She’s so lonely and depressed since Grandpa passed away, and her Alzheimer’s seems to get worse every day. She’s done so much for you over the years. Don’t you think you should pay her a visit?

18. Scare Tactics
Trump: “There is a great hatred toward Americans by large segments of the Muslim population. Its going to get worse and worse. You’re gonna have more World Trade Centers.” Mount Pleasant, South Carolina,

19. THE END 4
Chapter 8