Lesson 11: Criteria of a good argument

1. Lesson 11: Criteria of a good argument SOCI 108 - Thinking Critically about Social IssuesSpring 2012

2. Learning Outcomes • Differentiate inductive and deductive arguments • Identify vague, ambiguous, and over-generalized language • Practice evaluating arguments

3. Inductive Arguments • Premises provide support but not conclusive evidence for the conclusion • Room for doubt • IA can be stronger or weaker depending on the premises provided

4. Deductive Arguments • Assumes that if Premises are true then the Conclusion is true • Conclusion follows necessarily from the Premises • DA are true or false

5. Signal Words • IA • Probably, most likely, chances are, reasonable to suppose, we can expect that, probable that • DA • Necessarily • Certainly • Must be that

6. Example of an Inductive Argument • German Shepherds make good watchdogs • Max is a German Shepherd • Therefore, Max is probably a good watchdog.

7. Examples of a Deductive Argument • True Deductive Argument • All men are mortal • I am a man • Therefore, I am mortal • False Deductive Argument • All men are tall people • Danny DeVito is a man • Therefore, Danny DeVito is tall

8. Inductive or Deductive? • To the editor: Here we go again. In a recent issue of your paper, a letter writer says that if a unilateral ban on assault weapons were in effect, countless live would be saved. Prohibition didn’t prevent people from obtaining liquor. Abortion bans did not stop women from getting abortions. And yet we are to believe that a gun ban will, somehow magically, prevent lawbreakers from obtaining guns. Really, now. Just how stupid or blindly liberal, do the anti-gunners think we are? • Inductive

9. How to Analyze an Argument • What claims is being supported? • Conclusion • What claims do the supporting? • Premises • What claims are irrelevant to the argument? • Unnecessary information

10. Four Criteria for a Good Argument • Relevance Criterion • A premise is relevant if its acceptance provides some reason to believe , counts in favor of, or makes a difference to, the truth or falsity of the conclusion • Sociology students must take soci108, Bob is a sociology major, Bob must take soci108. • Cows give milk, nursing mothers produce milk, milk is good for building strong bones • Dogs are cats, cats are felines, so dogs are felines.

11. Logically Irrelevant • Acceptance of a statement has no bearing on, provides no evidence for, or makes no difference to, the truth or falsity of its conclusion • The earth revolves around the sun, therefore you should get an A in this class. • Last night I dreamed I won the lottery, therefore I will win the lottery.

12. Four Criteria of a Good Argument • Acceptability Criterion • The premises must be acceptable (to a rational person..) • All fishes have wings, whales are fishes, therefore whale have wings. • All dogs have five legs, Baxter is a dog, so Baxter has five legs. • Contradictory premises • Since God can do anything, (premise) • God can make a stone so heavy he can’t lift it (premise)

13. Four Criteria of a Good Argument • Sufficient Grounds Criterion • There must be enough supporting premises for a conclusion • They must be sufficient in number, kind, and weight

14. Four Criteria of a Good Argument • Rebuttal Criterion • A good argument should also provide an effective rebuttal to the strongest arguments against one’s conclusion • A rebuttal must: • Raise the issue • AND then refute it • Ex: “my opponent would say…”

15. Principle of Charity • Interpret unclear statements generously • Don’t interpret as a bad premise when the evidence reasonably permits us to interpret it as not a premise at all.

16. Author’s Intent • Is it the author’s intent to PROVE something? • Or is to explain WHY something is? • i.e., to offer an account • This is offering an explanation, not stating an argument

17. Applying Criteria for sound Arguments • Workbook page 19