Critical Thinking and Arguments Chapter 1

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

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

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

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

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

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

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

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

Truth-Value Indicating whether a statement is true or false

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

A sentence can contain two or more statements

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

What are the two statements in this one sentence?

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

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

Exercise 1.1 Break up into groups and do A 1-10 C 1-10 D 1-5 E 1-5

Why Think Critically? Helps us make good decisions

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

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

Second Step: Find the conclusion The main point

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

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

Premise Indicator Words Because Since On account of Base on

Exercise 1.2 P. 14-15 B 1-10

1.2B #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

1.2B #2 (Argument) (1) Every time you hang out with him, you feel miserable __________________ (2) Therefore, you shouldn’t go out with him

1.2B #3 (Argument) I have seen 1,000 swans (2) All of the swans I have seen are white ___________________________________ (3) therefore, most swans are white

1.2B #4 (Argument) Gas prices will rise The housing market will continue to slump ______________________________________ (3) Therefore, the U.S. will fall into a recession next year

1.2B #5 (Argument) Carbon-dioxide emissions are higher (2) Atmospheric particles are increasing _________________________________ (3) Therefore, global temperatures will rise over the coming century

1.2B #6 (No Argument) Why? Only part of an argument 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)

1.2B #7 (Argument) Mary W. was a woman Mary W. was a famous women philosopher ______________________________________ (3) Some famous philosophers are women

1.2B #8 (Argument) I have seen him at Starbucks most days about this time _______________________________________ (2) Therefore, he is probably at Starbucks

1.2B #9 (No Argument) Statement of fact, not trying to convince

1.2B #10 (Argument) (1) It is my favorite kind of Vietnamese noodles. _______________________________________ (2) Therefore, you will like it

Complicating Factors

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

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

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

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

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

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

Enthymeme Arguments with an unstated premise or conclusion

Exercise 1.4 P. 21-22 A 1-5

1.4A #1 Unstated premise: [1] Suicides are undesirable

1.4A #2 Unstated premise [1] People should do things that make them less likely to be victims of crime

1.4A #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

1.4A #4 Unstated conclusion: [1] Therefore, The U.S. should adopt a single-payer health care system

1.4A #5 Unstated conclusion: [1] Therefore, she did not take Bio 101