Answers to Exericse 7B(A) in Writing Logically, Thinking Critically
(Thanks to Madeleine Murphy)


1. Inductive. The speaker has gathered some general information (no lights, not answering calls) and come up with an inference that may be perfectly reasonable, but isn't necessarily true. All of these premises may be true, but may still yield another answer. (Marie may just hate him!)

2. Deductive. If we accept the generalization that cat lovers don't care for dogs, and if Colette is a cat lover, then it must be true that she doesn't like dogs.

3. Inductive. if you look at it this way: the speaker is making a prediction based on evidence (all the pollsters saying the candidate will win). But in another way, one could argue it's deduction. Perhaps the speaker means that all candidates who lead in November always win. And since this candidate is leading in November, he must be about to win.

4. Deductive. If both premises are true (Philippe is French, and the French love wine) then it must absolutely follow that Philippe loves wine. Note, by the way, how this follows the quality-group pattern of deductive reasoning that you've seen before in the "Hidden Assumptions" in Chapter 3. (Philippe has this quality--he loves wine--because he is French.)

5. Inductive. The reasoning moves from particular examples to a general, and in this case, unstated conclusion&emdash;American presidents lie to thier consitiuents&emdash;a conclusion that does not follow of necessity.

6. Inductive. It worked on two hundred occasions; so we conclude that it would work today. This is a piece of classic induction, and the basis of all human understanding!

7. Deductive. If the premises are true, then the conclusion must be true. This goes to show how deductive arguments can be misleading. It sounds so convincing, and indeed the logic is flawless--but are the premises sound? What does it mean to be "well-informed?" Can it really be possible for an entire generation to contain not even ONE person who is at least as well-informed as his predecessors?

8. Deductive. A generalization is applied to a particular, with the conclusion following of necessity.


Comments
(thanks to Madeleine Murphy)

You may find you've got them all reversed, almost 100% wrong. That's quite common! Actually the reason is usually this: You see a general statement ("Cat lovers don't like dogs") and assume that since induction is the means we use to make generalizations, this must be an inductive statement. But not necessarily. Think about it: induction is how we make generalizations, how we draw general conclusions. If the conclusion of the argument is a generalization, then OK, it's probably inductive. But deductive arguments, remember, start or are based on generalizations.

Remember, this is all about drawing inferences. What generalizations can we make from details? When we know (or accept) one statement to be true, what else must that mean? These are the concerns of logic.