Phil 04 – Spring 06 Homework Five
Anderson
1. You construct an argument that you think is very persuasive, but it fails to persuade anyone to whom you present it. It follows that your argument must be a piece of bad reasoning. T or F
2. If an argument fails to justify its conclusion, it is reasonable to infer that the conclusion must be false. T or F
3. Two arguments are often better than one. T or F
4. Not every statement you may make requires an argument if it is to qualify as reasonable. T or F
Problems 5-7, answer valid, cogent or neither.
5. If the governor pardons him, we will be the laughing stock of the nation. The reason is if the governor pardons him, his opponents will go on television arguing that the state is soft and unprincipled and if they say that on television, we will be the laughing stock of the nation.
6. The sign on the parking meter says “Out of Order”. It follows that the parking meter is not working.
7. All fish can live underwater. Harold is not a fish, so Harold cannot live underwater.
8. A respected physicist at a famous aeronautical laboratory writes, in an article in the food section of the Sacramento Bee, that you can lose weight by eating only foods that are very light in weight (that is, of low density).
Give two reasons why anyone who believed this person on the grounds that he is a respected physicist would be committing a faulty appeal to authority.
Problems 9-10, legitimate ad hominem or fallacious ad hominem?
9. Sylvia Crawford insists that we should avoid using drugs. She argues that nicotine, marijuana, cocaine and amphetamines are all proven to be dangerous to health, addictive, and at the very least, can impair intellectual abilities. But it turns out that Sylvia drinks a full pint of Scotch whiskey every evening and surely alcohol is also a drug that can be dangerous to one’s health. Sylvia has no business arguing against drugs when she can’t get her own drinking problem under control.
10. “Ladies and Gentlemen of the jury: You have heard the chief prosecution witness swear that he saw the defendant running from the burglarized store the night of the burglary. But don’t believe a word of it! After all, that witness has himself been convicted of burglary in the past and he is testifying against the defendant in hopes that the defendant will be convicted and he (the witness) will therefore no longer be a suspect in this burglary.
11. Which of the following statements are a priori, which are empirical (a posteriori)?
(a) Lynn is coming to the picnic or she isn’t.
(b) You cannot change the past.
(c) There is life on other planets.
(d) The average American family has 2.2 children.
(e) If A is older than B and B is older than C then A is older than C.
(f) If A is a parent of B and B is a parent of C then A is a parent of C.
Problems 12-13, are arguments by reductio ad absurdum. Clearly illustrate the structure of the reasoning by (a) Stating first the claim that the maker of the argument intends to refute. (b) Then state the logical implication (or implications) that follow from that claim that are thought to be obviously false or “absurd”.
12. Problem 8, page 352.
13. Problem 10, page 353.
14. Problem 7, page 259. This is an argument from anecdote. Rewrite the argument to clearly illustrate the logical structure of the reasoning. Be sure to state the conclusion clearly. Does it commit the fallacy of argument by anecdote?
15. Problem 2, page 248. What is the conclusion of the reasoning? Is the argument cogent? Justify your answer.
16. Problem 11, page 378. Does this argument commit the slippery slope fallacy? Justify your answer.