Critical Thinking and Arguments Chapter 1 1 Critical

Critical Thinking and Arguments Chapter 1 1

Critical Thinking • Critical thinking is the skill of • 1. correctly evaluating arguments • 2. making good arguments 2

What is an Argument? • The reasons you give to try to convince someone of something 3

Premises and Conclusions • Premises are the reasons • Conclusions are what you are trying to convince the person to accept 4

Standard Form of Argument • (1) Premise #1 (Reason #1) • (2) Premise #2 (Reasons #2) Therefore (3) Conclusion (Belief you want accepted) 5

Statement • A statement is a sentence that makes a claim that can be either true or false 6

• The conclusion is the statement that the argument is intended to support • The premises are the statements that are intended to support the conclusion 7

Key Concept • Premises and conclusions must be statements • And every statement is either true or false 8

Not Statements! • Questions • Exclamations • Commands • When evaluating arguments • - Exclude these • - Ignore these 9

Truth-Value • Indicating whether a statement is true or false 10

Statements and Sentences • Sentences are determined by rules of grammar • Statements are determined by whether it makes a claim that can be true or false 11

• A sentence can contain two or more statements 12

Example p. 9 • Because so much of modern medicine depends on chemistry, it is essential that students who intend to enter the health professions have some understanding of basic chemistry 13

• What are the two statements in this one sentence? 14

Answer • (1) (Because) so much of modern medicine depends on chemistry, • (2) it is essential that students who intend to enter the health professions have some understanding of basic chemistry 15

• Statement (1) = Premise • (1) (Because) so much of modern medicine depends on chemistry, • Statement (2) = Conclusion • (2) it is essential that students who intend to enter the health professions have some understanding of basic chemistry 16

Exercise 1. 1 • Break up into groups and do • • A 1 -10 C 1 -10 D 1 -5 E 1 -5 17

Why Think Critically? • Helps us make good decisions 18

Finding Arguments • Find a set of statements (premises) that someone claims supports another statement (conclusion) • This is an Art not Mechanical 19

First Step: Look for an attempt to convince • Arguments are responses to • Difference of opinions • Disagreements • Controversies 20

Second Step: Find the conclusion • The main point 21

Conclusion Indicator Words • P. 14 • • Therefore Consequently As a result of Thus 22

Third Step: Find the Premises • How is the conclusion supported? • Why does the person believe this position? • What are their reasons? 23

Premise Indicator Words • P. 14 • • Because Since On account of Base on 24

Exercise 1. 2 • P. 14 -15 • B 1 -10 25

1. 2 B #1 (Argument) (1) Exchange-traded fund result in lower capital gains (2) Exchange-traded funds result in lower taxes ___________ (3) Therefore, Exchanged-traded funds should be considered by investors in higher tax brackets 26

1. 2 B #2 (Argument) (1) Every time you hang out with him, you feel miserable _________ (2) Therefore, you shouldn’t go out with him 27

1. 2 B #3 (Argument) (1) I have seen 1, 000 swans (2) All of the swans I have seen are white __________________ (3) therefore, most swans are white 28

1. 2 B #4 (Argument) (1) Gas prices will rise (2) The housing market will continue to slump ___________________ (3) Therefore, the U. S. will fall into a recession next year 29

1. 2 B #5 (Argument) (1) Carbon-dioxide emissions are higher (2) Atmospheric particles are increasing _________________ (3) Therefore, global temperatures will rise over the coming century 30

1. 2 B #6 (No Argument) • Why? Only part of an argument (1)If you eat to much, then you will gain weight (2) You ate too much ___________ (3) Therefore, you gained weight (Modus Ponens: Affirm the antecedent) 31

1. 2 B #7 (Argument) (1) Mary W. was a woman (2) Mary W. was a famous women philosopher ___________________ (3) Some famous philosophers are women 32

1. 2 B #8 (Argument) (1) I have seen him at Starbucks most days about this time ____________________ (2) Therefore, he is probably at Starbucks 33

1. 2 B #9 (No Argument) • Statement of fact, not trying to convince 34

1. 2 B #10 (Argument) (1) It is my favorite kind of Vietnamese noodles. ____________________ (2) Therefore, you will like it 35

Complicating Factors 36

Indicator words are imperfect guides • Some arguments might not have indicator words 37

Sentence order • Conclusions do not always follow premises • Many times the conclusion comes first 38

Conclusions and Premises not in declarative form • Sometimes • Interrogatives (questions) • Imperatives (commands) 39

Remember • Only statements should be parts of an argument • Not all sentences are statements • Well-formed arguments contain only declarative sentences 40

Unstated Conclusion • When the author does not explicitly state the argument’s conclusion 41

Unstated Premises • 1. Author believes that a statement is true • 2. Intends for that statement to be part of the argument • 3. But does not include that statement in the formal argument 42

Enthymeme • Arguments with an unstated premise or conclusion 43

Exercise 1. 4 • P. 21 -22 • A 1 -5 44

1. 4 A #1 Unstated premise: [1] Suicides are undesirable 45

1. 4 A #2 Unstated premise [1] People should do things that make them less likely to be victims of crime 46

1. 4 A #3 Two unstated premises: [1] Raised cost and decreased quality is un. American [2] Un-American is a bad thing Unstated conclusion: [3] A single-payer health care system would be bad 47

1. 4 A #4 Unstated conclusion: [1] Therefore, The U. S. should adopt a singlepayer health care system 48

1. 4 A #5 Unstated conclusion: [1] Therefore, she did not take Bio 101 49