Directions: For Problems 1-10, determine whether the given statement is either True (A) or False (B).

Transcription

1 Critical Thinking Exam 2: Chapter 3 PLEASE DO NOT WRITE ON THIS EXAM. Directions: For Problems 1-10, determine whether the given statement is either True (A) or False (B). 1. Valid arguments never have false premises. 2. Even when an inductive argument is cogent, there will always remain some room for doubt about whether the conclusion is true. 3. Inductive arguments are either 100% strong or 100% weak. 4. If an argument is inductively strong, then the premises in the argument must be true. 5. An argument can be sound but also have false premises. 6. Statistical arguments are generally intended to be inductive arguments. 7. Valid means basically the same thing as true. 8. Deductive arguments are either 100% valid or 100% invalid. 9. When we assess the validity or strength of an argument, we are testing the inference of the argument. 10. Arguments from definition are typically inductive arguments. 11. A three-statement argument in which all the premises begin with the words all, some, or no is called a(n) a. argument from analogy. b. hypothetical syllogism. c. modus ponens argument. d. categorical syllogism. 12. Inductive inferences can be either a. valid or invalid. b. sound or unsound. c. true or false. d. strong or weak. 13. By definition, an inductive argument with a weak inference is a. uncogent. b. deductive. c. unsound. d. invalid. 14. An argument in which the conclusion does not follow necessarily from the premises should nonetheless be treated as deductive if... a. the conclusion in the argument is clearly true. b. it is scientifically certain that the premises are true. c. the language or the context makes clear that the arguer intended to offer a logically conclusive argument. d. the premises, if true, would make the conclusion very likely to be true.

2 15. Which of the following is not a common pattern of deductive reasoning? a. modus ponens b. argument by elimination c. statistical argument d. argument from definition 16. What deductive pattern does the following argument represent? If the Warriors are ever going to develop a competitive playoff team, they will have to spend what it takes to get a premier player. But the Warriors will never spend that kind of money on one player. So, the Warriors will never develop a competitive playoff team. a. Argument by Elimination c. Categorical Syllogism d. Causal Argument 17. Which inductive pattern does the following argument best represent? The human brain is like a very complex computer. Both computer and the brain receive and store data for future reference. Both make calculations and draw conclusions from data they have collected. But when a computer is filled with inaccurate information, it will nearly always yield inaccurate calculations and yield false conclusions. Hence, it seems likely the same is true of the human brain. For these reasons, it is imperative that we avoid filling our brains with inaccurate and misleading information. a. Statistical argument. b. Argument from authority c. Predictive argument d. Argument from analogy 18. The argument All men are women; Justin Bieber is a man; so, Justin Bieber is a woman is a. valid but unsound. b. invalid and unsound. c. strong and uncogent. d. weak and uncogent. 19. An argument in which the conclusion follows with strict logical necessity from the premises is said to be a. cogent. b. valid. c. strong. d. implicative. 20. Which of the following is not a common pattern of inductive reasoning? a. causal argument b. hypothetical syllogism c. inductive generalization d. predictive argument 21. Both Sound and Cogent arguments must have a. a valid inference b. a strong inference c. true premises d. all of the above

3 22. Which of the common patterns below does the following argument represent: If the Democrats are going to win the election in 2008, then they had better appeal to religious voters. But Democrats will lose many progressive supporters if they appeal to religious voters. Thus, If the Democrats are going to win in 2008, they ll lose many progressive supporters. a. Modus Ponens c. affirming the consequent d. chain argument e. disjunctive syllogism 23. Which of the common patterns below does the following argument represent: Either embryos have a right to life or there are no moral grounds for objecting to stem cell research. But there are excellent reasons to object to stem cell research. Thus, Embryos must have a right to life. a. Modus Ponens c. affirming the consequent d. argument by elimination 24. In order for an argument to be sound, the argument must be a. deductive b. strong c. valid d. both a and b e. both a and c 25. In order for an argument to be cogent, the argument must be a. inductive b. strong c. valid d. both a and b e. both a and c 26. The primary difference between a deductive and an inductive argument is that a. in a deductive argument, the conclusion is always certain or necessary, whereas an inductive argument often has a false conclusion. b. an inductive argument can only establish mere opinions, but deductive arguments establish facts. c. the author of a deductive argument intends for their conclusion to follow from the premises with strict logical necessity, whereas the author of an inductive argument intends for their conclusion to follow with probability. d. all of the above Directions: For 27-32, determine whether each of the following arguments is either Deductive (A) or Inductive (B). (1 point each) 27. Everything that comes to exist must have a cause of its coming to be. Thus, the universe itself must necessarily have a cause, since it obviously came to exist. 28. No government has the right to force people to pay taxes. Therefore, the United States government has no right to force people to pay taxes.

4 29. In a recent Gallup poll, 72 percent of Californians said they support the death penalty for minor crimes such as drug possession and petty theft. Gallup polls are, in general, highly reliable. Thus, approximately 72 percent of Californians probably do approve of using the death penalty to punish minor crimes such as drug possession and petty theft. 30. My accusers say that I am an atheist and that I do not believe in the gods. But they agree that I do believe in demigods. But if so, it follows that I am not an atheist. For if the demigods are the illegitimate sons of gods, whether by the nymphs or by any other mothers, then this necessarily implies the existence of the gods, their parents. 31. If Denise plays first base, then Laura plays shortstop; if Laura plays shortstop, then Tess plays catcher; so, if Denise plays first base, then Tess plays catcher. 32. Many teenagers who listen to heavy metal music act violently later on. So, it seems likely that listening to heavy metal music causes young people to engage in violent behavior. Directions: For 33-42, determine whether the following deductive arguments are either Valid (A) or Invalid (B). (1 point each) 33. Yesterday, the professor said that anyone caught cheating on the exam would receive an F on the test. And I happen to know that several students did receive an F on the exam. So it follows that some students must have been caught cheating. 34. All Republicans are opposed to the federal healthcare law. Barack Obama is a Republican. So, Barack Obama is opposed to the federal healthcare law. 35. If Arnold is an Austrian citizen, then he s European. But Arnold is not a citizen of Austria. So he must not be European. 36. Some Asian American voters are Republicans. Many Republicans voted for George W. Bush. Hence, it follows that at least some Asians voted for George W. Bush. 37. Either Donnor or Wilhelm will prevail in the running contest. However, Wilhelm has dropped out due to a sprained ankle. Thus, Donnor will surely win. 38. Carl: I m going to bring my cigar to the restaurant tonight. That way, if I get the urge for a nicotine fix, I ll just light it up. Sam: Are you crazy? People will be outraged if you smoke a cigar at the restaurant. After all, it s against the law to smoke indoors in public! Carl: I respectfully disagree. I read the notice at the restaurant carefully last time I was there. It stated, Smoking of cigarettes and pipe tobacco is prohibited in this restaurant, and cigars are obviously neither. So they must be allowed. 39. Whatever Oprah says is true. Oprah said that eating meat is dangerous. So eating meat must be dangerous. 40. A person is addicted to a substance if he or she cannot voluntarily stop using it. Many smokers are unable to quit. Thus, for these people at least, smoking is an addiction.

5 41. Professor Martin never intentionally lies for any reason. Professor Martin says that there have been contacts between the CIA and intelligent aliens from outer space for decades. It clearly follows that there have been such contacts since at least the 1990s. 42. Some animals are blue. Some animals are birds. So, at least some animals must be blue birds. Directions: For Indicate whether each of the following inductive arguments are Strong (A) or Weak (B). (1 point each) 43. If it rains, the ceremony will be moved indoors. According to the National Weather Service, there s a 75 percent chance of rain. So, it would be sensible to prepare to set up for the ceremony indoors. 44. Its ridiculous to claim that women are underrepresented in positions of political power. After all, Hillary Clinton is the Secretary of State for the most powerful country on Earth. Angela Merkel is Chancellor of Germany, the strongest economy in Europe. And the president of Chile, one of the most prosperous countries in South America, is Michelle Bachelet, a woman! 45. Last Tuesday I went to the Icky Enchilada for lunch. I ordered a burrito that turned out to have a cockroach in it. I ate there again on Thursday evening and I found fingernail clippings in my refried beans. On Saturday, I decided not to order food there, yet they served my beer in a glass that still had lipstick on it. I d have to say the Icky Enchilada is not a very sanitary place to dine. 46. For the last 3 years, I ve visited Chicago on the Fourth of July, and the weather was always sunny and beautiful. My cousin Jim, who visits Chicago for a Blues music festival every June, has always commented on the mild and pleasant weather. I think I ll take the family to Chicago for Christmas this year since the weather there is always so nice and warm. 47. Four out of my five professors this semester are women. I guess most professors are women. 48. Last Monday evening I crashed my car. Just before the accident, I noticed the moon was full. A few weeks ago, I was walking across the quad and I tripped on a rock. Oddly, this happened just as I was noticing the moon was full. So, I suppose I ought to make sure I mark my calendar so that I ll remember to just stay home during the next full moon. 49. The Bank of America on Main St. was robbed yesterday. It may sound strange, but I know Jenny needed money to pay off her student loans. Two days ago, she told me she bought a gun for protection. Yesterday morning, I saw her at the bus stop right in front of the very Bank that was robbed. And today I noticed Jenny and her boyfriend, Mark, eating at that expensive restaurant on 2 nd and Lotus St. drinking a fancy bottle of wine. We d better call the police. I bet its Jenny who robbed the Bank of America yesterday. 50. According to my dentist, Dr. Snow, fluoride helps prevent tooth decay by making the tooth more resistant to acid attacks from plaque bacteria and sugars in the mouth. Moreover, the American Dental Association and virtually every other major association of professional dentists as well as faculty at dentistry colleges agree that fluoride is a safe and effective method of reducing the occurrence of tooth decay. Admittedly, a minority of experts disagree with this conclusion. Yet, it seems reasonable to accept that fluoride likely does help prevent tooth decay.