Chapter 5 - Repairing Arguments

Question 1

Unstated Premise/Conclusion

Answer 1

Sometimes we must repair an argument by adding an unstated premise or unstated conclusion.

Question 2

Mark of Irrationality

Answer 2

If you recognize that an argument is good, then it is irrational not to accept the conclusion as true.

Question 3

Principle of Rational Discussion

Answer 3

We assume that the person who is trying to convince us:

1. Knows about the subject under discussion.
2. Is both willing and able to reason well.
3. Is not lying.

Question 4

Guide To Repairing Arguments

Answer 4

Repair an argument if:

1. The argument becomes stronger or valid
2. The premise is plausible to you and other person
3. The premise is more plausible than conclusion

Question 5

Unrepairable Argument

Answer 5

We do not repair an argument if:

1. There is no argument there.
2. The argument is so lacking in coherence
3. There is nothing obvious to add.
4. A premise it uses is false or very dubious, or some of the premises are contradictory and cannot be deleted.
5. The obvious premise to add would make the argument weak.
6. The obvious premise to add to make the argument strong or valid is false.
7. The conclusion is clearly false.

Question 6

Prescriptive Claims

Answer 6

You can’t get “ought” from “is.” You can not get a prescriptive conclusion from premises that are descriptive.

Question 7

Indicator Word

Answer 7

Conclusion – so, thus, therefore, consequently

Premise – since, because, given that, it follows

Question 8

Irrelevant Claim

Answer 8

A premise is irrelevant if you can delete it and the argument does not become weaker.

Question 9

Imply and Infer

Answer 9

Imply: when someone leaves a conclusion unsaid

Infer: when you decide that an unstated claim is the conclusion