1. Critical Thinking and Arguments
Chapter 1

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

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

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

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

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

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

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

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

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

11. 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

12. A sentence can contain two or more statements

13. 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

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

15. 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

16. 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

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

18. Why Think Critically?
Helps us make good decisions

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

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

21. Second Step: Find the conclusion
The main point

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

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

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

25. Exercise 1.2 P
B 1-10

26. 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

27. 1.2B #2 (Argument)
(1) Every time you hang out with him, you feel miserable __________________ (2) Therefore, you shouldn’t go out with him

28. 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

29. 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

30. 1.2B #5 (Argument) Carbon-dioxide emissions are higher
(2) Atmospheric particles are increasing
_________________________________
(3) Therefore, global temperatures will rise over the coming century

31. 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)

32. 1.2B #7 (Argument) Mary W. was a woman
Mary W. was a famous women philosopher
______________________________________
(3) Some famous philosophers are women

33. 1.2B #8 (Argument)
I have seen him at Starbucks most days about this time
_______________________________________
(2) Therefore, he is probably at Starbucks

34. 1.2B #9 (No Argument)
Statement of fact, not trying to convince

35. 1.2B #10 (Argument)
(1) It is my favorite kind of Vietnamese noodles. _______________________________________ (2) Therefore, you will like it

36. Complicating Factors

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

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

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

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

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

42. 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

43. Enthymeme
Arguments with an unstated premise or conclusion

44. Exercise 1.4 P
A 1-5

45. 1.4A #1
Unstated premise: [1] Suicides are undesirable

46. 1.4A #2
Unstated premise [1] People should do things that make them less likely to be victims of crime

47. 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

48. 1.4A #4
Unstated conclusion: [1] Therefore, The U.S. should adopt a single-payer health care system

49. 1.4A #5
Unstated conclusion:
[1] Therefore, she did not take Bio 101