Relevance Premises are relevant to the conclusion when

  • Slides: 78
Download presentation
Relevance • Premises are relevant to the conclusion when the truth of the premises

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

Non Sequitur • Latin for “it does not follow” • Irrelevant premises 2

Non Sequitur • Latin for “it does not follow” • Irrelevant premises 2

Exercise 2. 6 A 1 -10 Do as class 3

Exercise 2. 6 A 1 -10 Do as class 3

Independent Premise • A premise that is intended to provide support for the conclusion

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

Dependent Premises • A premise that is intended to provide support for the argument’s

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

Exercise 2. 7 • Break up into groups • A 1 -10 7

Exercise 2. 7 • Break up into groups • A 1 -10 7

2. 7 A #1 (1) Socrates was a human being (2) All human beings

2. 7 A #1 (1) Socrates was a human being (2) All human beings are mortal Therefore, (3) Socrates was mortal Argument with relevant, dependent premises 8

2. 7 A #2 (1) Transfatty acids lead to heart disease (2) Children shouldn’t

2. 7 A #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

2. 7 A #3 (I) Julia Roberts is either a man or a woman

2. 7 A #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

2. 7 A #4 (I) If you walk on the lines in the sidewalk,

2. 7 A #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

2. 7 A #5 (I) All cows are pigs (2) All pigs are ducks

2. 7 A #5 (I) All cows are pigs (2) All pigs are ducks Therefore, (3) All cows are ducks Argument with relevant, dependent premises 12

2. 7 A #6 (1) If Reza had fallen, he would have a bump

2. 7 A #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

2. 7 A #7 (I) The coffee cup was still warm (2) The newspaper

2. 7 A #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

2. 7 A #8 (1) Many people think that air pollution is a serious

2. 7 A #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

2. 7 A #9 Not an argument 16

2. 7 A #9 Not an argument 16

2. 7 A #10 (I) A survey indicated 26% of voters in favor of

2. 7 A #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

Arguing about Arguments 18

Arguing about Arguments 18

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

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

Refutation Argument • An argument whose conclusion is that another argument fails the true

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

Fallacies • Untrue, false, inaccurate, wrong reasoning • Something you don’t want to commit

Fallacies • Untrue, false, inaccurate, wrong reasoning • Something you don’t want to commit 21

Red Herring • The Red Herring fallacy occurs whenever someone makes a statement or

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

Straw Man Fallacy Easy Target Fallacy • When you restate your opponent's argument in

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

Appeal to Fear • An Appeal to Fear occurs when someone claims that if

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

Appeal to Pity • Appeals to Pity are a close relative of Appeals to

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

Appeal to Popularity • The fallacy of Appeal to Popularity occurs when someone argues

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

Appeal to Novelty or Tradition • The fallacy of Appeal to Novelty or Tradition

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

2. 9 • Do as class 28

2. 9 • Do as class 28

Ad Hominem • A person commits the Ad Hominem fallacy when he attacks a

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

Appeal to Ignorance • Someone commits the fallacy of Appeal to Ignorance when he

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

Guilt by Association • A form of the Ad Hominem Fallacy • When people

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

Begging the Question • When you assume to be truth that which you are

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

Exercise 2. 10 • Break up into groups • A 1 -10 33

Exercise 2. 10 • Break up into groups • A 1 -10 33

Chapter 2 Review 34

Chapter 2 Review 34

What makes a Good Argument? 35

What makes a Good Argument? 35

Two Characteristics of Good Arguments • 1. The premises are true • 2. The

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

True Premises • The premises are true when what they say about the world

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

Proper Form There is a relationship or connection between the premises and conclusion that

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

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

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

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

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

If all the members of the class of things called MEN have a particular

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

Why? Because we have established a necessary / logical connection between the premises and

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

Examples (1) All men are mortal (2) Socrates is a man There: (3) Socrates

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

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

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

Sound Deductive Argument • Valid argument with true premises 45

Sound Deductive Argument • Valid argument with true premises 45

Audience • The audience of the argument is the group that the person making

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

The Problem of Ignorance • The problem of ignorance is that we don’t know

The Problem of Ignorance • The problem of ignorance is that we don’t know everything 47

Modus Ponens (MP) Affirm the Antecedent (1) If A, then B (2)We have A

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

Correct Form Example Affirm the Antecedent (1) If Mary is a mother (A), then

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

Incorrect Form Example: Affirm the Consequent (1) If Mary is a mother (A), then

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

You must learn the FORM • 1. If it rains tomorrow (A), then I

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

Correct Form • 1. If it rains tomorrow (A), then I will bring my

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

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

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

Correct Form Example Deny the Consequent (1) If Mary is a mother (A), then

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

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

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

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

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

Inductive Arguments From Specific Examples to General Principle Gives Probability 57

Inductive Arguments From Specific Examples to General Principle Gives Probability 57

Example (1) There are trees on Island 1 (2) There are trees on Island

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

Weak vs. Strong Inductive Arguments The more examples / evidence, the stronger the argument

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

Strong and Weak Inductive Arguments • Strong Inductive Arguments have many examples (Cogent) •

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

Relevance • Premises are relevant to the conclusion when the truth of the premises

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

Non Sequitur • Latin for “it does not follow” • Irrelevant premises 62

Non Sequitur • Latin for “it does not follow” • Irrelevant premises 62

Independent Premise • A premise that is intended to provide support for the conclusion

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

Dependent Premises • A premise that is intended to provide support for the argument’s

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

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

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

Refutation Argument • An argument whose conclusion is that another argument fails the true

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

Fallacies • Untrue, false, inaccurate, wrong reasoning • Something you don’t want to commit

Fallacies • Untrue, false, inaccurate, wrong reasoning • Something you don’t want to commit 68

Red Herring • The Red Herring fallacy occurs whenever someone makes a statement or

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

Straw Man Fallacy Easy Target Fallacy • When you restate your opponent's argument in

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

Appeal to Fear • An Appeal to Fear occurs when someone claims that if

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

Appeal to Pity • Appeals to Pity are a close relative of Appeals to

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

Appeal to Popularity • The fallacy of Appeal to Popularity occurs when someone argues

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

Appeal to Novelty or Tradition • The fallacy of Appeal to Novelty or Tradition

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

Ad Hominem • A person commits the Ad Hominem fallacy when he attacks a

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

Appeal to Ignorance • Someone commits the fallacy of Appeal to Ignorance when he

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

Guilt by Association • A form of the Ad Hominem Fallacy • When people

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

Begging the Question • When you assume to be truth that which you are

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