Deductive Fallacy Practice Exercises

Review the lesson for Deductive Fallacy Study Guide.

Deductive Fallacy Practice Exercises

Practice Exercise

Rewrite the following argument to remove the slippery slope fallacy:

We shouldn't give military aid to other countries. The next thing you know, we will have thousands of troops overseas dying for no good reason.

Answer

Realistic, possible reasons why we should not give military aid to other countries include: it's too dangerous; they will keep asking for more; we shouldn't let our military get spread out too thinly, etc.

Practice Exercise

Which of the following is NOT a false dilemma?

1. The thing he saw in the sky was either an alien spacecraft or a helicopter.
2. I can't believe my senator voted against the healthcare bill. Either she didn't understand the bill, or she just doesn't care about people less fortunate than herself.
3. The awards are being given out tonight. Either we'll win for best musical this year or we won't.
4. We have to drill for more oil right now or we'll end up with no power for light, heat, cooling, computers, or TV.

Answer

Choice c isn't a false dilemma; it's a statement of fact about something that really does have just two possible outcomes: we win or we don't. The other statements each give two options when there are other possibilities.

Practice Exercise

Which of the following does not beg the question?

1. I like the Brewers because they're my favorite team.
2. Ghosts exist because I saw something once that could only have been a ghost.
3. The Seafood Shack is the best restaurant in town because it's so much better than all the others.
4. They signed Bruce Springsteen to headline the concert because he's a rock legend and a huge star.

Answer

Choice d does not beg the question. It gives two reasons why Springsteen was signed. It would have been an example of circular reasoning if it said: "They signed Bruce Springsteen to headline the concert because he's a concert headliner."

Practice Exercise

Which word in each example is the equivocation?

1. A feather is light. Something light can't be dark. So a feather can't be dark.
2. It's just natural to want to save our natural resources.
3. Mark's parents told him to do what's right. He has the right to drop out of school at age 18.

Therefore, 17-year-old Mark should drop out of school on his next birthday.

4. Branches have leaves. A bank has branches, so bank branches must have leaves.

Answer

1. light
2. natural
3. right
4. branches