Two Basic Types of Arguments Deductive Inductive Premises support the conclusion. Support happens in degrees: probability & strong vs. weak arguments. We have to evaluate the weight of the support (BOC & IBE). Premises demonstrate or prove the conclusion. Validity: It isn’t possible for the premise to be true and the conclusion to be false. Soundness: The premise is true and argument is valid.
Generalizing What is it? Why do it? How do we do it? Tell us what seems to be generally true about CR students CR math teachers CR English teachers CR counselors and advisors CR cafeteria food
The Sample Needs to be Sufficient & Representative Hasty Generalization (generalizing from too few cases, fallacy of small sample or fallacy of the lonely fact) Argument by Anecdote Generalizing from Exceptional Cases Biased Sample Self-Selection Fallacy CR students CR math teachers CR English teachers CR counselors and advisors CR cafeteria food
Homework 2. Stress bad for you? That’s a myth. I know all sorts of type A people who are in excellent health. generalizing from exceptional cases 4. I had a great time at the party last night; I’ll be all university parties are great. hasty generalization 8. Most Americans watch American Idol. That’s clear since over one million people cast votes on the season finale. hasty generalization 10. I tried to by a portable heater from the Saber Company last winter, and it was back-ordered. After a month, I just cancelled and decided not to do any more business with them. hasty generalization 14. These days young people don’t like expensive cars. You hardly ever see a teen ager driving a Maserati. hasty generalization 22. Given the right circumstances, humans will always revert to savages. Look at the Nazis. generalizing from exceptional cases
Analogies What are they? Why do we use them? CR students in MW classes buy more Coke than Pepsi in the cafeteria, so I’ll be CR students in TTH classes will buy more Coke than Pepsi too. Weak Analogy & False Analogy Lack of fundamental, relevant similarities. Presence of fundamental, relevant dissimilarities. CR students taking night classes want the library to be open on weekends, so I’ll be CR students taking day classes want the library to be open on weekends too.
Homework 3. These university kids drink like crazy on Halloween and St. Patrick’s Day. They probably drink like crazy on Christmas, too. weak analogy 6. Salmon is very bad for dogs. You shouldn’t let your cat eat it either, I guess. weak analogy 13. The professor is a fantastic teacher. He should run for congress. weak analogy 21. You would not go in the woods if you knew there were bears in there, and the same thing, therefore, holds for getting into a bear market. Hang onto your money until the market changes. weak analogy
Appeals to Emotion, Authority, Common Belief, & Tradition or Common Practice What is “an appeal”? How do we make appeals? Why would we make appeals? When do they work & when do they fail (or become “faulty appeals”) The appeal has to be appropriate to the circumstances. When might it be appropriate to appeal to offer an emotional appeal? An appeal to authority, common belief, or tradition?
Homework 5. The prayer leader cured her rheumatism. She said he did, and who would know better than she? faulty appeal to authority 18. My son thinks Galaxies are better than iPhones, and he should know since he is a teenager. faulty appeal to authority 19. I’m putting my money in a Vanguard account. My history teacher think the firm has the best mutual funds, and he is a smart man. faulty appeal to authority
I think we should give Jack a raise. He doesn’t have any spending money at all, and he’s always having to make excuses about not being able to go out with the rest of his friends because of that. Jill, on the other hand, seems to be getting along just fine on her salary.” You know, our third grader’s friend Joe comes from an impoverished family. He looks to me as though he doesn’t get enough to eat. I think I’m going to start inviting him have dinner at our house one or twice a week.
Statistics show that flying is much safer than driving. So why put your family at risk? This summer, travel the safe way: fly United Airlines. If you ask me, I think ending your relationship with Brittany is a big mistake. Remember that she stuck by you last year when you really needed somebody. Should you really repay her by dumping her?
Letter to the editor: “Your food section frequently features recipes with veal, and your ads say veal is a wholesome, nutritious food. Well, I have a different opinion of veal. Do you know how it comes to be on your plate? At birth, a newborn calf is separated from its mother, placed in a dark enclosure, and chained by its neck so it cannot move freely. This limits muscular development so that the animal is tender. It is kept in the dark pen until the day it is cruelly slaughtered.”
Fallacies of Cause and Effect Post Hoc, Ergo Propter Hoc: “After this; therefore, because of this.” Cum Hoc, Ergo, Propter Hoc: With this; therefore, because of this. How can we determine that one event is the cause of another event?
Complications in Cause & Effect Claims Overlooking the possibility of coincidence. Overlooking a possible common cause. Overlooking the possibility of random variation. Overlooking the possibility of regression. Students in my 8:30 am class were completely uninterested in my lecture and falling asleep, so I added some jokes to the lecture for my 10:00 class, and the class loved the lecture. I’m going to start adding jokes to all my lectures. I gave the class a short quiz at the beginning of class, and the students scored far below average. After listening the lecture and being retested, students scored closer to the average on the quiz. I guess the lecture worked well.
Homework 12.The heart attack rate spikes the day clocks are set ahead for daylight saving time, demonstrating how time change can affect our health. cum hoc 15. Prostate cancer is almost unheard of in countries where they don’t eat meat, proof positive that mean in your diet will lead to prostate cancer. cum hoc 24. My student evaluations were better this year. I’ll be it’s because I had to cancel class two times. post hoc 25. Statistics show that smokers disproportionately come from low-income areas. We are trying to figure what it is about poverty that makes people smoke. cum hoc
Fallacy of Accident: Assuming that a General Principle Applies to an Exceptional Case 7. You have to stand up for what you believe. Ignore it if your wife complains about how fast you’re driving. 9. ONE GUY: The guy Paulson shot had climbed through a window and was coming down the darkened hallway. ANOTHER GUY: Doesn’t matter; he still should have been charged with murder because the guy he shot was unarmed. 17. The new law says everybody who takes a firearms course can carry a concealed weapon, so I don’t see why I can’t take my gun to school. 20. Be prepared. We are traveling to a Third World country; there won’t be any good hotels. 23. We live in a democracy. That’s why children should be allowed to vote.
What’s wrong with socialism? I’ll tell you what’s wrong with socialism. Americans don’t like it. That’s what wrong with socialism. “Everybody or most people or many believe X is right/true/good, so X must be right/true/good.”
Scare tactics and Argument by Force. Threatening rather than reasoning. Motivating by fear rather than reason. So you want to know why you should try to do well on these logic exercises in class today? I’ll tell you: because if you don’t, I’ll ask you to leave and not return.
Some people have the gift of psychic power and can read minds. Don’t believe me? Name one scientists or identify one study that proves no one has psychic power.
There are very good reasons for the death penalty. First, it serve as a deterrent to those who would commit capital offenses. Second, it is just and fair punishment for the crime committed. Third, reliable polls show that over 70% of all Americans favor it. Why should I put a note on this guy’s car that I just dented? Do you think he’d put a note on my car if he put a dent in it?
Can I prove the Biblical flood really happened? Hey, can you prove it didn’t? There is no evidence against the theory of evolution, so until someone produces that evidence, I’m going to accept the theory as a credible one.
Animal rights people shouldn’t pick on rodeos about animal treatment. If they’d come out and see the clowns put smiles on kids’ faces and see horses buck off the cowboys and hear the crowd go “ooh” and “ahh” at the bullriding, why, then, they’d change their minds. An irrelevancy brought in to “support” a claim or to distract one from the issue.
Can I prove the Biblical flood really happened? Of course it happened! Why else would Noah build an ark? Stephen Colbert: “George W. Bush: great president or greatest president?”
I believe that when we die, we are all given new, young, perfect bodies, and we spend eternity with those whom we love. I can’t imagine the point of life if it all just ends when we die! “Historically, marriage has been restricted to heterosexual couples. Therefore, it’s right to restrict marriage to heterosexual couples.” “You’re giving me grief for downloading music on a P2P network?? Please. Who doesn’t do that these days?
Hands off our freedom, atheists Letter to the editor, Times Standard 08/29/2013 I agree with Dr. Lawrence's “My Word” (”Atheists' lawsuits disrespect our nation,” Times-Standard, Aug. 20, Page A4). I am so sick and tired of atheists attacking us Christians with idiotic lawsuits. We don't try to sue atheists because they don't believe in God. If atheists want respect, they should be respectful. They twist the Constitution claiming that separation of church and state means no prayer, and no religion at all in any government office. That is not what separation of church and state means! It was put in the Constitution so the government couldn't tell us how to worship. The pilgrims came to America to escape religious persecution. My problem with atheists isn't because they don't believe like I do. My problem with them is their constant complaining and whining and filing silly expensive lawsuits. The only aim of such lawsuits has nothing at all to do with the Constitution but it is to take away the freedom of Christians. We are told by atheists that we can pray in church or at home but that we shouldn't pray in public. They tell us where we can display nativity scenes. They want prayer out of the schools. It wasn't very far back in history that schoolhouses were used as churches on Sundays. If atheists don't want to be labeled as negative then they need to keep their hands off our freedom! No, Dr. Lawrence, you need not apologize. The atheists need to give us Christians an apology. Becky Payton , Eureka