Logical fallacies in rhetoric.

1. Fallacies How to be weak and unconvincing in arguments…

2. Making arguments Most writing tasks require you to make an argument. When you make an argument, you make a claim and present evidence to support that claim. The strength of your argument depends on how good your evidence is, and how well it supports your claim.

3. Fallacies When an argument fails or is weak, it is called a fallacy. You’ll want to avoid using fallacies in your writing. You’ll also want to be able to identify fallacies in other people’s writing. WHY?

4. Either-or In this fallacy, you make the case that there are only 2 alternatives, when in fact there are almost always more! America: love it or leave it. You’re either with us or against us. Atheism is the only alternative to Fundamentalism.

5. Hasty generalization Making assumptions about a whole group based on a sample that is inadequate. Wealthy people are snobs. Librarians are shy and smart. My roommate said her philosophy class was hard, and the one I’m in is hard, too. All philosophy classes must be hard.

6. Oversimplification Taking a complex situation or topic and simplifying it way too much. The question of whether to allow stem cell research comes down to this: do we want to heal the sick or not? We should pull the troops out today—if the soldiers are back home, they’ll be safe.

7. Rationalization Making excuses or offering a weak explanation. I’m not prepared because the dog ate my homework. I’m late because of all the road construction.

9. If we legalize marijuana, more people will try heroin.

11. Begging the question The claim is restated and offered as evidence—you’re going around in circles and not offering real evidence! No one is permitted to use the gym on weekends, since people are permitted to use the gym only on weekdays. Since I’m not lying, it follows that I’m telling the truth. The reason I say he’s unattractive is that he’s ugly.

12. Post hoc Assuming that because B comes after A, A caused B. Sequence is NOT necessarily causation. Every time I wear my red socks to a Utah football game, the Utes win. I’d better keep wearing my red socks! Before women got the right to vote, there were no nuclear weapons. Every morning on my farm, the rooster crows, and then the sun comes up. That must be a very powerful rooster!

13. Non sequitur Making an argument that does not follow logically. Two unrelated ideas are offered as claim and evidence. Bob lives in a large apartment building. His apartment must be huge! The war is righteous because we are French! My religion is true because it helps a lot of people.

14. Bandwagon appeal Suggesting that everyone is doing it, so you should, too. Because it’s popular, it must be right. It doesn’t matter if I cheat because everybody does it. In the 1800’s there was a widespread belief that bloodletting cured illness. In fact, it made people sicker, but it persisted because it was so popular.

15. Polarization Representing the opposing group as extreme. All feminists are man haters. Republicans are… Democrats are…

16. Straw man Making your opponent’s position look so extreme or ridiculous that any reasonable person would reject it. Evolution means a dog giving birth to a cat, so it’s obviously a silly theory. My opponent says that we should not fund the attack submarine program. I disagree entirely. I can’t understand why he wants to leave us defenseless like that.

17. Ad hominem Attacking the person instead of the argument. I don’t believe a word you say because you’re big, fat, and ugly! People who believe in UFO’s are stupid. Joe is wrong because he is a jerk.

18. Name the fallacy… Wealthy people are snobs. America: love it or leave it. The question of whether to allow stem cell research comes down to this: do we want to heal the sick or not? I’m not prepared because the dog ate my homework. If I make an exception for you, I’ll have to make an exception for everyone.

19. Name the fallacy… Evolution means a dog giving birth to a cat, so it’s obviously a silly theory. Joe is wrong because he is a jerk. It doesn’t matter if I cheat because everybody does it. All feminists are man haters. Before women got the right to vote, there were no nuclear weapons.

20. Name the fallacy… Since I’m not lying, it follows that I’m telling the truth. The solar system reminds me of an atom, with planets orbiting the sun like electrons orbiting the nucleus. We know that electrons jump from orbit to orbit, so it must be possible for planets to do so, too. Bob lives in a large apartment building. His apartment must be huge!