1. Logical fallacies * Sources include The language of composition from Bedford/st.martin

2. Definition
Errors or weaknesses in reasoning that undermine an argument
This logical breakdown often occurs in the use of evidence
Fallacies may be accidental or deliberate—used to manipulate or deceive
Avoid these common fallacies in your own
arguments and watch for them in the
arguments of others.

3. Hasty Generalization
Making assumptions about a whole group or range of cases based on a sample that is inadequate; not enough evidence to support a particular conclusion [fallacy of insufficiency]
Ex:
Smoking is not bad for you; my great aunt smoked a pack a day and lived to be 90.

4. Begging the question Also known as circular reasoning
Speaker repeats the claim as a way to provide evidence resulting in no evidence
[fallacy of insufficiency]
Ex:
Buy this shampoo because it’s the best shampoo!
Dogs are a menace to society because they are dangerous.

5. Red Herring
The speaker skips to a new and irrelevant topic in order to avoid the topic of discussion.
[a fallacy of relevance]
Ex:
We can debate these regulations until the cows come home, but what the American people want to know is, when are we going to end this partisan bickering?

6. Ad hominem Latin for “against the man” [fallacy of relevance]
Switching the argument from the issue at hand to the character of the other speaker
*It’s valid to examine character if it is RELEVANT to the topic. Ex: if court case hinges on testimony of single witness who is a con artist.
Ex:
Her economic plan is impressive, but remember: this is a woman who spent six weeks in the Betty Ford Center getting treatment for alcoholism.

7. Weak/faulty Analogy
Analogy between 2 things that are NOT comparable (often focusing on irrelevant or inconsequential similarities) [fallacy of relevance]
Ex:
Guns are like hammers—they're both tools with metal parts that could be used to kill someone. And yet it would be ridiculous to restrict the purchase of hammers—so restrictions on purchasing guns are equally ridiculous.

8. Speaker presents 2 extreme options as the only possible choices
False dichotomy
Speaker presents 2 extreme options as the only possible choices
[fallacy of accuracy-oversimplification]
Ex:
Either we agree to higher taxes or our grandchildren will be mired in debt.

9. Straw man
Speaker chooses deliberately poor or oversimplified example in order to ridicule or refute an opponent’s viewpoint; misrepresenting someone’s argument to make it easier to attack
(think—easy to knock down a straw man=scarecrow)
Ex: After Will said that we should put more money into health and education, Warren responded by saying that he was surprised that Will hates our country so much that he wants to leave it defenseless by cutting military spending.

10. Post hoc (post hoc ergo propter hoc)
post hoc ergo propter hoc is Latin for “after which therefore because of which”
It is incorrect to always claim that something is a cause just because it happened earlier.
Correlation does NOT imply causation.
Ex: We elected Johnson as president and look where it got us: hurricanes, floods, stock market crashes.
When proving causality or using historical evidence, be aware of this fallacy. Consider complexity of the situation. Check your facts. Proceed with caution.

11. Appeal to false authority
Citing as an authority someone who has no expertise to speak on the issue.
Ex: TV star is not a medical expert, even though pharmaceutical advertisements often use celebrity endorsements.

12. Everybody’s doing it, so it must be a good thing to do.
Ad populum
“Bandwagon” appeal
Everybody’s doing it, so it must be a good thing to do.
Ex:
You should vote for Rachel Johnson—she has a strong lead in the polls!
But officer, I don't deserve a ticket; everyone goes this speed.

13. Slippery slope
Speaker claims that small first step leads to a chain of related events culminating in some significant effect, much like an object given a small push over the edge of a slope sliding all the way to the bottom;
a sort of chain reaction, ending in some dire consequence
Ex:
We've got to stop them from banning pornography. Once they start banning one form of literature, they will never stop. Next thing you know, they will be burning all books!

14. Appeal to pity
Speaker tried to persuade by making audience feel sorry for someone
Ex:
It's wrong to tax corporations—think of all the money they give to charity, and of the costs they already pay to run their businesses!
I should receive an 'A' in this class. After all, if I don't get an 'A' I won't get the scholarship that I want.