This chapter will cover Reality assumptions Patterns of deductive reasoning Using deductive reasoning to test logic discover truth make decisions avoid stereotyping and understand argument ID: 655644
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Slide1
Chapter 3: Reality Assumptions
This chapter will cover
Reality assumptions
Patterns of deductive reasoning
Using deductive reasoning to test logic, discover truth, make decisions, avoid stereotyping, and understand argument.Slide2
Reality Assumptions
Based on unique experience of individual
Beliefs about what is true and factual about the world.Slide3
Detecting Reality Assumptions
Toulmin’s Model
Issue:
Should we use the SAT or ACT scores to predict success in college?Slide4
Toulmin’s
Model
Claim -
Students should not apply to colleges at which SAT scores are 200 points higher than theirs.
Reason
Students will not likely succeed
Warrant
(Reality Assumption)
Scores are accurate predictions of how well a student is prepared
Based onSlide5
Toulmin’s
Model
Reason
Test only predicts level of struggle for first year.
Warrant
(Reality Assumption)
Students success based on character qualities that are not measured by the tests.
Claim
Colleges
should not use standardized test scores as a measure of success.
Based onSlide6
Toulmin’s Model
Issue:
Should trials and executions be televisedSlide7
Toulmin’s Model
Claim: Trials and executions should be televised
Reason:
Public has the right to have more information about the courts and the judicial system.
Warrant
(Reality Assumption)
Televising trials would inform the public about our judicial system.
Warrant
(Value Assumption)
Freedom of information is an important value
Based onSlide8
Reasoning
Deductive Reasoning
General statement to a specific instanceSlide9
Reasoning
Deductive
Aims for
Certainty
General
to
Specific
Inductive
Gives us
Probabilities
Specific
to
General
Chapter 6Slide10
Deductive Reasoning
Syllogism- a classic example
All men are mortal.
(major premise)
Socrates is a man
.
(minor premise)
Therefore, Socrates is mortal.
(conclusion
)
Slide11
Deductive Reasoning
Validity
Correct form makes an argument
valid (logical)
.
Accurate content makes it
true.
When the form is valid and the content is true, the argument is
sound.
Slide12
Deductive Reasoning
is content true?All students eat pizza.
Claire is a student at CSU.
Is form valid?
Therefore, Claire eats pizza.
Is it sound?
NoSlide13
Deductive Reasoning
is content true?All women are terrible drivers.
Jane is a woman.
Is form valid?
Therefore, Jane is a terrible driver.
Is it sound?
YesSlide14
Deductive Reasoning
Pattern of Deductive reasoning
All As are Bs.
Categorical statement
m is A.
Therefore, m is BSlide15
Deductive Reasoning
B
A
A statement in which
members of one
class are said
to be included in
Another class.
Categorical Statement
All As are Bs.Slide16
Conditional/hypothetical syllogism
Modus ponens:
‘the way of affirmation’: the antecedent leads to the consequent.
If A, then B
A Therefore, B
A
BSlide17
Conditional/hypothetical syllogism
If I have strep throat, then the culture will be positive.
But the culture is not positive.
So, I don’t have strep throat.
Modus tollens:
‘denying the consequent.’
If A, then B
Not A
Therefore not B
A
BSlide18
Deductive Reasoning
Questionable Premises
All drivers who speed are subject to a fine.
You are speeding
.
Which premise can be contested?
Therefore, you are subject to a fine.Slide19
Deductive Reasoning
Enthymeme
Key part is implied rather than directly stated
.Slide20
Deductive Reasoning
Sound Argument:
Correct Form
True Premises
Unsound Argument:
Incorrect Form,
True Premises
Unsound Argument:
Correct Form
Untrue Premises
Unsound Argument:
Incorrect Form,
Untrue Premises
True
False
Valid
InvalidSlide21
Deductive Reasoning
Deductive reasoning can:
Uncover Reality Assumptions
Discover Truth and Make Decisions
Combat Prejudice and StereotypingSlide22
Skill A critical thinker uses reasoning to discover truth and prevent stereotypingSlide23
Chapter 3: Reality Assumptions
Checkup
Reality versus value assumptions
Validity in an argument
What makes a deductive argument sound
What does deductive reasoning aim to establish