Informal Logic and Thinking Tools!

1. Informal Logic and Thinking Tools!

2. What’s going on here??? Burn the Witch!!!!

3. Definition…Logic • The study of the nature of arguments. • Know known as “Critical Thinking.” • Developed by the Greek Philosopher Aristotle. • What is an argument? • a group of statements that attempt to establish a claim. • Conclusion—the claim that an argument is trying to establish.

4. Why study Logic? • Logic is the foundation of “deep thinking” or Philosophy • Learning to think logically will help you become a better philosopher • Becoming a better philosopher will make philosophy more enjoyable • You will stop believing whatever you hear and start asking “why?” or “by what argument?” • You will be able to better formulate your own Arguments • You will be able to spot fallacies

5. Welcome Back! • Bell Ringer… • Objective and Agenda: Through notes, discussion, and scenarios, students will identify the components of an argument. • QUIZ TOMORROW! • What is Logic? • What is an argument?

6. The 6 Mistakes We Make in Thinking (Kida, 2007)

7. The 6 Mistakes We Make in Thinking (Kida, 2007) 1. We prefer stories to statistics. OR Which do YOU prefer?

8. The 6 Mistakes We Make in Thinking (Kida, 2007) 2. We seek to confirm, not question, our ideas. We see what we want to see But is this professional?

9. The 6 Mistakes We Make in Thinking (Kida, 2007) 3. We rarely appreciate the role of chance and coincidence. Yes. Could this be a coincidence?

10. The 6 Mistakes We Make in Thinking (Kida, 2007) 4. We sometimes misperceive the world around us. Is this a face on Mars!? Or a problem with our focus?

11. The 6 Mistakes We Make in Thinking (Kida, 2007) 5. We tend to oversimplify our thinking. Is Hillary Orwellian? Is Bush a Dunce? The truth is probably more complex.

12. The 6 Mistakes We Make in Thinking (Kida, 2007) 6. Our memories are often inaccurate. Researchers are able to purposely create false memories. Hypnotists can do it by mistake!

13. Some notes to consider… • First, arguments can be either really short or they can be really long (like op-eds and books,) but really long arguments will usually be broken down into series of shorter ones. • Second, its important to recognize that having an argument doesn’t mean that your argument is any good. An argument might be such that its premises are false or irrelevant to the conclusion, or that they fail entirely to support the conclusion.

14. Arguments vs. Explanations • Both answer the questions why? So it can be tricky to tell the difference. • Argument- answers the question “Why should I accept this conclusion?” • Explanation-takes the conclusion as a given (as a fact) and then offers a story about why that particular thing is the case rather than thatit is the case.

15. Not everything is an argument!“A string of statements asserting or clarifying…views does not an argument make” • Not an argument:“I hate George Bush. Every time I see his face I want to step on it.” (assertion) • Not an argument:“I can’t stand Hillary Clinton. She’s such a Woman of the ‘80s--you can imagine her in a power-suit with shoulder-pads out to there and a scarf tied in a bow as a pretend necktie.” (clarification) • Not an argument:“I don’t like Obama or Romney either.” (statement in the interest of being Fair and Balanced)

16. Examples… Ms. Krall: You didn’t turn your homework in Sally. Sally: My dog ate my homework. • Sally is offering an explanation for why it is that she failed to turn in her homework. • She is not trying to convince me that she failed to turn it in; We both agree that she failed to turn it in.

17. Examples • Billy: Why did I fail this class. Ms. Krall? • Ms. Krall: You didn’t turn in your work, Billy. • Billy: My dog ate my work.

18. Comparing the two… • Although both sentences are identical, Billy is offering an argument. • He is claiming (implying) that he shouldn’t fail because his dog ate his work. • And it’s his intentions that makes his sentence an explanation

19. Logic Workbook • Answer the 5 discussion problems • Share with your group.

20. Good Morning! • Bell Ringer… • Agenda and Objectives: Through notes and an activity students will identify premises and conclusions to deductive arguments. • Define Logic • Define argument • What’s the difference between an argument and explanation? • Quiz on Friday!

21. Welcome Back! • Take a few minutes to review for your quiz…

22. Good Morning! • Agenda and Objectives: Through notes and an activity students will identify premises and conclusions to deductive arguments.

23. Types of Arguments! • Deductive argument • Inductive argument • Argument whose premises make its conclusion certain. • Argument who premises make its conclusion likely.

24. Aristotle • Considered the Father of Logic • Syllogism- “an extremely subtle, sophisticated, or deceptive argument.” (Deductive Reasoning) • Orconsists of exactly three claims, two of which are premises and one of which is the conclusion

25. Breakdown of the argument… • Premise: a reason offered as support for another claim • Conclusion: the claim being supported by a premise or premises • Argument: a conclusion together with the premises that support it • So, to take the oldest example in logic, one that Aristotle used in teaching at his Academy: • 1. All men are mortal. • 2. Socrates was a man. • 3. Therefore Socrates is mortal • What is the conclusion? • What are the premises?

26. All men are mortal Mo Mortal men mortals

27. Socrates is aman men

28. Socratesismortal men mortals

29. And another thing…. • Sometimes premises can have more than one conclusion. • Ex. Since yesterday’s editorial cartoon succeeded in making the mayor look silly, the cartoonist must have finally regained his touch. And the mayor probably won’t be reelected. Premise: Yesterday’s editorial cartoon succeeded in making the mayor look silly. Conclusion: The cartoonist has finally regained his touch. And Premise: Yesterday’s editorial cartoon succeeded in making the mayor look silly. Conclusion: The mayor probably won’t be reelected.

30. Identify premises and conclusions… • Premise Indicators • Since • Because • For • As • Follows from • As shown by • Inasmuch as • As indicated by • The reason is that • May be inferred from • May be derived from • May be deduced from • Given that • Conclusion Indicators • Therefore • Hence • So • Accordingly • In consequence • Consequently • Proves that • As a result • Thus • For this reason • For these reasons • It follows that • I conclude that • Which shows that • Which means that • Which entails that • Which implies that • We may infer

31. Review! • Syllogism- “an extremely subtle, sophisticated, or deceptive argument.” (Deductive Reasoning) • Or consists of exactly three claims, two of which are premises and one of which is the conclusion

32. Bell Ringer Review… • What is a premise? • What is a conclusion • What is a Syllogism?

33. Activity… • With a neighbor, identify the premise(s) and conclusion (s) of each argument. • Underline the premise(s) • Circle the conclusion (s)

34. Good Morning….

35. The Enthymeme • “a syllogism or other argument in which a premise or the conclusion is unexpressed.” • Meaning- it’s implied!!! • Example: “I live in Wisconsin, so I am probably a Green Bay Packer Fan” • What is the missing premise? • “Most people from Wisconsin are Green Bay Packer Fans.”

36. However, sometimes premises or conclusions are implied (page 13.) • Ex. “You spilled it. Whoever makes the mess cleans up the mess.” • What is clearly implied here is the conclusion: You clean up the mess. • Ex. You should not eat that greasy hamburger. It is loaded with fat. • What is the implied premise? • (You should not eat anything that is loaded with fat. )

37. Example 1 • Bill only owns blue pants and brown pants. Bill is wearing a pair of his pants today. So Bill is wearing either blue or brown pants today. • Deductive! The two premises (first 2 sentences) guarantee the truth of the conclusion.

38. Example 2 • January has always been cold here in Siberia. Today is January 14, so it is going to be another cold day in Siberia. • Inductive.Premise makes the conclusion likely, but does not guarantee that the conclusion is true. (it is possible that the premise could be true and the conclusion could still be false.)

39. Another example… • Peach number 1 contains a pit. • Peach number 2 contains a pit. • Peach 3 contains a pit…and so on until… • Peach 1,000 contains a pit. • Conclusion: All peaches contain pits! • The premises do not logically entail the conclusion-it remains possible that the 1,001st peach will not contain a pit. Still despite not being deductively valid, we still suppose the conclusion will be true.

40. Good morning… • Bell Ringer… • Agenda and Objective: Through exercises students will identify invalid statements by using the counter argument and Venn Diagram strategies. • Turn to page 5 in your packet. Read about “Point of Issue” and do the 5 exercises. What is the point of each argument?

41. Packet Exercises… • Premise: All human beings (a) are mortal (b) • Premise: Corky (c) is a human being (a) • Conclusion: Corky (c) is mortal (b) • All A are B • C is A • Therefore C is B

42. Validity • A deductive argument is validif it has a form that would make it impossible for the premises to be true and the conclusion false. • If a deductive argument is valid, then its premises' being true would guarantee that its conclusion is true.

43. Checking Validity • Valid- logical form of argument whereas “Truth” refers to the relationship of a statement to the objects that it describes in the world. • Some arguments can be valid with false premises. • Invalid- has some problems with its logical form, such as an ambiguous key term. It is possible for an invalid argument to have all true premises. • Two ways… • Counter argument • Venn Diagram

44. Practice #1-the counter argument • The most convincing way to show invalidity of an argument is to present a counter example • In defining the case for invalidity, the premises are true but the conclusion is false

45. Practice…#1The Counter argumentFrom Alice's Adventures in Wonderland • “Then you should say what your mean,” the March Hare went on. • “I do, “ Alice hastily replied; “at least-at least I mean what I say-that’s the same thing, you know.” • “not the same thing a bit!” said the Hatter. “you might just as well say that ‘I see what I eat’ is the same thing as “I eat what I see’!” • “you might just as well say,” added the March Hare, “that ‘I like what I get’ is the same thing as ‘I get what I like’!” • “you might just as well say,” added the Dormouse, who seemed to be talking in his sleep, “that “I breathe when I sleep’ is the same thing as “I sleep when I breathe’!” • It is the same thing with you,” said the Hatter, and here the conversation dropped, and the party sat in silent for a minute…

46. Example…Alice’s premise • Premise: “I say what I mean is the same as I mean what I say.” • Argument Form: • (A) I say what I mean is the same as (B) I mean what I say • A is B

47. The Counter argument… • The Hatter responds… • “I see what I eat (A)” is the same thing as “I eat what I see! (B)” • A is B

48. Practice #1-the counter argument • From Alice's Adventures in Wonderland do the following… • Put the premises on the March Hare and the Dormouse into argument form and explain how they represent the use of counter example to show invalidity…

49. Answer… • The March Hare • Argument Form..(A) “I like what I get” is the same thing as (B) “I get what I like!” • A is B • (first statement is true, second false) • The Dormouse • Argument form: (A) “I breathe when I sleep” is the same thing as “I sleep when I breathe!” • A is B • (first statement is true, second false)

50. Checking validity Valid Invalid Has some problems with its logical form, such as being ambiguous. It is possible for an invalid argument to have all true premises. • Refers to the logical form of an argument whereas “truth” refers to the relationship of a statement to the objects it describes in the world. • So an argument can be valid with false premises