Reconstructing Assumptions

edited 11/20/16

For each of the examples below representing a truncated argument (enthymeme) construct an additional sentence (or two) which could serve as a premise(s) that renders a valid (not necessarily sound) argument.

A needed assumption could be: Paraplegics cannot be not good lawyers.

(This in turn could be questioned to discover the assumptions underlying it.)

This requires more in the way of assumptions to render a valid argument.

Some might be:

  1. One personís getting hurt at an activity is sufficient evidence to judge that activity dangerous.
  2. John is a person and skiing is an activity.

These are sufficient to yield example B.

Remember: a valid argument is not necessarily a sound (or wise) one! (See An Introduction to Models of Reasoning)



(See also, What's the Connection?)

1. You canít trust Dan. He hasnít paid me the money he owes me.

2. Samís nervousness shows heís a coward.

3. Apples are inedible. Theyíre made of granite.

4. John is an environmentalist, so he will vote against building the dam.

5. Olivia is a baker, so she canít dance.

6. Anne must be insane. She hums constantly.

7. Mary doesnít speak French. She must not be well-educated.

8. Phil is an epileptic. Thatís why he failed.

9. Johnís failure indicates his lack of dedication.

10. John must be a good teacher; heís such a caring person.