Chapter 1 - Basic Concepts
1.4 Validity, Truth, Soundness, Strength, Cogency

Slide 2
Logic

Arguments

Slide 3
Review - Types of Arguments:

Slide 3
Validity and Strength

Soundness and Cogency

Slide 4
Validity and Soundness

Strength and Cogency

Truth Value

Slide 5
Summary thus far:

Slide 6
Deductive Arguments

Slide 7
Deductive Arguments - Valid

OR

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Deductive Arguments - Invalid

                                               OR

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Deductive Arguments - Examples
All pigs are winged-things. All winged-things are flying things.
Therefore, all pigs are flying things.

       All men are human. All women are human.
Therefore, all women are men.

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Deductive Arguments
The truth of the statements does not affect the validity of the argument
unless
all of the premises are true and the conclusion is false.

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Deductive Arguments
So, arguments with:

                                may be valid or invalid.

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Deductive Arguments - Prior Example
All pigs are winged-things. All winged-things are flying things.
Therefore, all pigs are flying things.

Slide 13
Deductive Arguments

Slide 14
Inductive Arguments

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Inductive Arguments - Strong
An inductive argument is strong when the premises actually do support the conclusion to a high degree of probability.
OR
- An inductive argument is strong when it is improbable for all of the premises to be true and the conclusion false.

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Inductive Arguments - Weak

   OR

Slide17

                               All previous U.S. Presidents have been women.
So, the next U.S. President will likely be a woman.

                            Former President Clinton had sexual relations with Monica Lewinsky.
That is the reason that President Clinton was re-elected to his 2nd term.

Slide 18
Inductive Arguments
The truth of the statements does not affect the strength of the argument
                unless
all of the premises are true and the conclusion is false.

Slide 19
Inductive Arguments

true premises and a true conclusion,
false premises and a false conclusion,
false premises and a true conclusion,
or true and false premises,
may be strong or weak.

Slide 20

                    All previous U.S. Presidents have been women.
So, the next U.S. President will likely be a woman.

Slide 21
Inductive Arguments