1. Informal Logic Fallacies
Fifteen somewhat random examples

2. Am I wrong?

3. 1. Ad hominem (Attack on the person)
What Sue says about Johannes Kepler's astronomy of the 1600s must be just so much garbage. Do you realize she's only fifteen years old?

4. 2. Hasty Generalization
I've met two people in Nicaragua so far, and they were both nice to me. So, all people I will meet in Nicaragua will be nice to me.

5. 3. Post hoc ergo propter hoc
I ate in that Ethiopian restaurant three days ago and now I've just gotten food poisoning. The only other time I've eaten in an Ethiopian restaurant I also got food poisoning, but that time I got sick a week later. My eating in those kinds of restaurants is causing my food poisoning.

6. 4. Appeal to Tradition
Of course we should buy IBM's computer whenever we need new computers. We have been buying IBM as far back as anyone can remember.

7. 5. Attack on the Motive
Those scientists are only promoting global warming because they want more funding.

8. 6. Bandwagon/ Appeal to popularity
More and more people are buying sports utility vehicles. It is time you bought one, too.

9. 7. Appeal to Ignorance
Nobody has ever proved to me there's a God, so I know there is no God.

10. 8. Begging the Question/ Circular argument
"Women have rights," said the Bullfighters Association president. "But women shouldn't fight bulls because a bullfighter is and should be a man."

11. 9. Equivocation
Brad is a nobody, but since nobody is perfect, Brad must be perfect, too.

12. 10. Appeal to Authority
My 5th-grade teacher once told me that girls would go crazy for boys if they learn how to dance. Therefore, if you want to make the ladies go crazy for you, learn to dance.

13. 11. Slippery Slope
Mom: Those look like bags under your eyes. Are you getting enough sleep?
Jeff: I had a test and stayed up late studying.
Mom: You didn't take any drugs, did you?
Jeff: Just caffeine in my coffee, like I always do.
Mom: Jeff! You know what happens when people take drugs! Pretty soon the caffeine won't be strong enough. Then you will take something stronger, maybe someone's diet pill. Then, something even stronger. Eventually, you will be doing cocaine. Then you will be a crack addict! So, don't drink that coffee.

14. 12. Ad Misericordiam (Appeal to Pity)
I really deserve an “A” on this paper, professor. Not only did I study during my grandmother’s funeral, but I also passed up the heart transplant surgery, even though that was the first matching donor in 3 years.

15. 13. Dicto Simpliciter All Canadians are friendly.
Everyone in Japan speaks Japanese.

16. 14. FALSE ANALOGY
To say humans are immortal is like saying a car can run forever.
Making people register their own guns is like the Nazis making the Jews register with their government. This policy is crazy.

17. 15. HYPOTHESIS CONTRARY TO FACT
If Abraham Lincoln were alive today, he would agree with me
If only you had learned how to play the piano as a child, you would be a concert pianist today,

18. Love is a Fallacy
We are now going to watch a video of a performance based on the short story “Love is a Fallacy” by Max Shulman. As irritating as the characters may be (and they are), you should be able to see examples of many of the fallacies we have discussed in action.

20. Further Reading
The Nizkor Project
Logical Fallacies
Logical Arguments