Relevance. Premises are relevant to the conclusion when the truth of the premises provide some evidence that the conclusion is true

Transcription

1 Relevance Premises are relevant to the conclusion when the truth of the premises provide some evidence that the conclusion is true Premises are irrelevant when they do not 1

2 Non Sequitur Latin for it does not follow Irrelevant premises 2

3 Exercise 2.6A 1-10 Do as class 3

4 Independent Premise A premise that is intended to provide support for the conclusion by itself 4

5 Dependent Premises A premise that is intended to provide support for the argument s conclusion only when combined with another premise in the argument 5

6 6

7 Exercise 2.7 Break up into groups A

8 2.7A #1 (1) Socrates was a human being (2) All human beings are mortal Therefore, (3) Socrates was mortal Argument with relevant, dependent premises 8

9 2.7A #2 (1) Transfatty acids lead to heart disease (2) Children shouldn t be given foods that lead to heart disease Therefore, (3) Children should not be given foods with transfatty acids Argument with relevant, dependent premises 9

10 2.7A #3 (I) Julia Roberts is either a man or a woman (2) Julia Roberts is a man Therefore, (3) Julia Roberts isn t a woman Argument with relevant, dependent premises 10

11 2.7A #4 (I) If you walk on the lines in the sidewalk, you ll be eaten by bears (2) Sometime in the next week, someone will walk on the lines in the sidewalk Therefore, (3) Sometime in the next week, someone will be eaten by bears. Argument. Relevant (but not much) dependent premises 11

12 2.7A #5 (I) All cows are pigs (2) All pigs are ducks Therefore, (3) All cows are ducks Argument with relevant, dependent premises 12

13 2.7A #6 (1) If Reza had fallen, he would have a bump on his head (2) Reza didn t have a bump on his head Therefore, (3) Reza didn t fall Argument with relevant, dependent premises 13

14 2.7A #7 (I) The coffee cup was still warm (2) The newspaper was open on the dining room table (3) The microwave was heating up a frozen dinner [4] Each of these three scenes indicate someone was recently present in the room Therefore, [5] If someone was recently in the room, he or she couldn t have gone far Therefore, (6) The killer couldn t have gone far Argument with relevant, independent premises 14

15 2.7A #8 (1) Many people think that air pollution is a serious problem (2) Vehicle emissions are a significant cause of air pollution Therefore, (3) Most people support laws requiring a reduction in the emissions produced by cars Argument with relevant, dependent premises 15

16 2.7A #9 Not an argument 16

17 2.7A #10 (I) A survey indicated 26% of voters in favor of Smith (2) A slightly later survey indicated 23% of voters favored Smith Therefore, (3) It is likely that about 25% of voters will favor Smith in the election Argument with relevant, dependent premises 17

18 Arguing about Arguments 18

19 Counter Argument An argument that draws a conclusion opposed to another argument 19

20 Refutation Argument An argument whose conclusion is that another argument fails the true premises or proper form test 20

21 Fallacies Untrue, false, inaccurate, wrong reasoning Something you don t want to commit 21

22 Red Herring The Red Herring fallacy occurs whenever someone makes a statement or offers an argument that distracts attention away from the argument under discussion. 22

23 Straw Man Fallacy Easy Target Fallacy When you restate your opponent's argument in an inaccurate way so that you can argue against it 23

24 Appeal to Fear An Appeal to Fear occurs when someone claims that if you don t do or don t believe something, something bad will happen to you 24

25 Appeal to Pity Appeals to Pity are a close relative of Appeals to Fear. An Appeal to Pity occurs when someone claims that if you don t do or don t believe something, something bad will happen to someone else. 25

26 Appeal to Popularity The fallacy of Appeal to Popularity occurs when someone argues that a view is true on the grounds that it s popular 26

27 Appeal to Novelty or Tradition The fallacy of Appeal to Novelty or Tradition occurs when someone argues that a statement is true because people have either believed it for a short time (novelty) or for a long time (tradition). 27

28 2.9 Do as class 28

29 Ad Hominem A person commits the Ad Hominem fallacy when he attacks a person instead of arguing against the view the person asserts 29

30 Appeal to Ignorance Someone commits the fallacy of Appeal to Ignorance when he claims that a statement is true because it hasn t been shown to be false. 30

31 Guilt by Association A form of the Ad Hominem Fallacy When people are attacked based upon their association with a person, group or view that is considered objectionable 31

32 Begging the Question When you assume to be truth that which you are trying to prove 32

33 Exercise 2.10 Break up into groups A

34 Chapter 2 Review 34

35 What makes a Good Argument? 35

36 Two Characteristics of Good Arguments 1. The premises are true 2. The argument has proper form 36

37 True Premises The premises are true when what they say about the world is accurate 37

38 Proper Form There is a relationship or connection between the premises and conclusion that make you believe the conclusion is true 38

39 Deductive Argument You go from a general principle to a specific example It gives necessity 39

40 (1) All men are mortal (2) Socrates is a man Therefore (3) Socrates is mortal 40

41 If all the members of the class of things called MEN have a particular characteristic called MORTALITY And Socrates is a member of that class called MEN Then Socrates MUST have that characteristic called MORTALITY 41

42 Why? Because we have established a necessary / logical connection between the premises and the conclusion Such that if the premises are true then the conclusion must be true 42

43 Examples (1) All men are mortal (1) All A has B (2) Socrates is a man (2) C is A There: Therefore (3) Socrates is mortal (3) C has B 43

44 Valid Deductive Argument The conclusion follows necessarily from the premises 44

45 Sound Deductive Argument Valid argument with true premises 45

46 Audience The audience of the argument is the group that the person making the argument wants to convince 46

47 The Problem of Ignorance The problem of ignorance is that we don t know everything 47

48 Modus Ponens (MP) Affirm the Antecedent (1) If A, then B (2)We have A Therefore (3) We can affirm B 48

49 Correct Form Example Affirm the Antecedent (1) If Mary is a mother (A), then she must be a woman (B) (2) Mary is a mother (A) (3) Therefore, she must be a woman (B) 49

50 Incorrect Form Example: Affirm the Consequent (1) If Mary is a mother (A), then she must be a woman (B) (2) Mary is a woman (B) (3) Therefore, she must be a mother (A) 50

51 You must learn the FORM 1. If it rains tomorrow (A), then I will bring my umbrella (B) 2. I brought my umbrella (B) 3. Therefore what? 51

52 Correct Form 1. If it rains tomorrow (A), then I will bring my umbrella (B) 2. It rained (A) 3. Therefore? 52

53 Modus Tollens (MT) Deny the Consequent If A, then B We do not have B Therefore, we do not have A 53

54 Correct Form Example Deny the Consequent (1) If Mary is a mother (A), then she must be a woman (B) (2) Mary is not a woman (-B) (3) Therefore, she must not be a mother (-A) 54

55 Disjunctive Syllogism (DS) Deny the Disjunct Either A or B Not A Therefore B Either A or B Not B Therefore A 55

56 Reductio ad Absurdem (RAA) Reduce to an absurdity Reduce to a contradiction 56

57 Inductive Arguments From Specific Examples to General Principle Gives Probability 57

58 Example (1) There are trees on Island 1 (2) There are trees on Island 2 (3) There are trees on Island 3 (4) All Islands have trees 58

59 Weak vs. Strong Inductive Arguments The more examples / evidence, the stronger the argument 1,000,000,000 Islands have trees Therefore all Island have trees 59

60 Strong and Weak Inductive Arguments Strong Inductive Arguments have many examples (Cogent) Weak Inductive Arguments have few examples 60

61 Relevance Premises are relevant to the conclusion when the truth of the premises provide some evidence that the conclusion is true Premises are irrelevant when they do not 61

62 Non Sequitur Latin for it does not follow Irrelevant premises 62

63 Independent Premise A premise that is intended to provide support for the conclusion by itself 63

64 Dependent Premises A premise that is intended to provide support for the argument s conclusion only when combined with another premise in the argument 64

65 65

66 Counter Argument An argument that draws a conclusion opposed to another argument What your opponent gives An argument against your 66

67 Refutation Argument An argument whose conclusion is that another argument fails the true premises or proper form test Not necessarily against your argument, but that your argument is wrong 67

68 Fallacies Untrue, false, inaccurate, wrong reasoning Something you don t want to commit 68

69 Red Herring The Red Herring fallacy occurs whenever someone makes a statement or offers an argument that distracts attention away from the argument under discussion. 69

70 Straw Man Fallacy Easy Target Fallacy When you restate your opponent's argument in an inaccurate way so that you can argue against it 70

71 Appeal to Fear An Appeal to Fear occurs when someone claims that if you don t do or don t believe something, something bad will happen to you 71

72 Appeal to Pity Appeals to Pity are a close relative of Appeals to Fear. An Appeal to Pity occurs when someone claims that if you don t do or don t believe something, something bad will happen to someone else. 72

73 Appeal to Popularity The fallacy of Appeal to Popularity occurs when someone argues that a view is true on the grounds that it s popular 73

74 Appeal to Novelty or Tradition The fallacy of Appeal to Novelty or Tradition occurs when someone argues that a statement is true because people have either believed it for a short time (novelty) or for a long time (tradition). 74

75 Ad Hominem A person commits the Ad Hominem fallacy when he attacks a person instead of arguing against the view the person asserts 75

76 Appeal to Ignorance Someone commits the fallacy of Appeal to Ignorance when he claims that a statement is true because it hasn t been shown to be false. 76

77 Guilt by Association A form of the Ad Hominem Fallacy When people are attacked based upon their association with a person, group or view that is considered objectionable 77

78 Begging the Question When you assume to be truth that which you are trying to prove 78