Answers

first set

1. Premises: [a] and [b].
   Conclusion: [c].


2. Premise: [b].
   Conclusion: [a].


3. Premises: [a] and [b].
   Conclusion: [c].


4. Premises: [a] and [b].
   Conclusion: [c].


5. You can say that [b] and [c] are premises, or more precisely, the premises are [a] if [b], [b] whenever [c], and [c].
   Conclusion: [a].


6. Premise: I used all the parts.
   Conclusion: This stereo stand is finished.


7. Premise: Anyone with nothing better to do shouldn't have power.
   Conclusion: Local politicians should only get two terms in office.


8. Premise: The car won't start.
   Conclusion: It doesn't have gas in the tank.


9. Premise: The car doesn't have gas in the tank.
   Conclusion: It won't start.

second set

1. Assumed premise: Most laws that were passed democratically are just. This makes the argument inductively strong. The premise needed for a valid deductive argument, "All democratically passed laws are just," is not as plausible.


2. Assumed premise: You are not justifies in being critical of any book yoy have not read. This is plausible and makes the argument valid.


3. No assumed premise makes the argument either strong or valid. The weakest possible assumption, "If she was late with her rent check last month, she probably isn't reliable," is far too implausible.


4. Assumed premise: Wen Dave has just had a furious argument, it's usually not safe to let him drive. Strong argument. It isn't plausible to assume that Dave is an unsafe driver every time he has had a furious argument.


5. Assumed premise: When it is snowing, the air becomes warmer. Strong argument.


6. Assumed premise: If it isn't 8:04, the bus probably has not come yet. This makes the argument strong.


7. No assume premise makes the argument either strong or valid. The weakest possibility, "Very few children could make art," is too vague to be judged plausible.

third set

1. (1) Everyone from Artemus Ward knows how to tie their shoes.
   (2) Bradley tried and tried and couldn't do it.
   (3) [Therefore] She must not go to Artemus Ward.
   

2. (1) Our uninsured children have pressing needs.
   (2) The elderly face high medical costs.
   (3) The new health care bill is the right one to pass.
   (4) [Therefore] It will lead to higher taxes
   

3. (1) There is no talent here
   (2) The novel has no plot.
   (3) The novel has unsavory characters.
   (4) The novel is the result of stringing together a lot of big words.
   (5) [Therefore] When all you have is big words strung together, there's no talent.
   

4. (1) If he'd been perfectly innocent he wouldn't have been arrested
   (2) He was arrested.
   (3) He has a suspicious smirk on his face.
   (4) [Therefore] He's not innocent.
   

5. (1) She won't be able to afford private schools for her kids.
   (2) She speculated in real estate.
   (3) Real estate has been a money loser lately.
   (4) She bought a lot of art.
   (5) She plowed the rest into her retirement account.
   (6) [Therefore] She has no liquid capital.
   

6. (1) They have no convincing alibi for the night of the 14th.
   (2) They can't explain what happened to their shotgun.
   (3) They owed the victim money.
   (4) They had a motive.
   (5) It makes a winning case.
   (6) [Therefore] I'm pressing charges.