Ch. 8: deductive arg.

Question 1

deductive argument

Answer 1

claims that its conclusion necessarily follows from the premises.
-presented in the form of syllogisms, with two supporting premises and a conclusion.

Question 2

form of an argument

Answer 2

determined by its layout or pattern of reasoning.

Question 3

valid

Answer 3

-the form of the argument is such that the conclusion must be true if the premises are true.

Question 4

valid ex:

Answer 4

All A are B.
C is A.
C is B.

Question 5

Sound

Answer 5

• (1) it is valid, and (2) the premises are true.

- Not all valid arguments for sound. Can still be unsound if one of the premises is false.

Question 6

Sound ex:

Answer 6

All men are mortal (true)
Socrates is a man (true)
Socrates is mortal (has to be true)

Question 7

Quantity

Answer 7

whether a categorical proposition is universal or particular.

-Particular (qualifiers: “Some”)

Question 8

Quality

Answer 8

• Affirmative (qualifiers: “All,” “Every,” “Some are”)

- Negative (qualifiers: “No,” “None,” “Some are not”)

Question 9

Universal Affirmative

Answer 9

All A are B.

Question 10

Universal Negative:

Answer 10

No A are B.

Question 11

Particular Affirmative:

Answer 11

Some A are B.

Question 12

Particular Negative:

Answer 12

Some A are not B.

Question 13

Arguments by Elimination

Answer 13

Rule out different possibilities until only one possibility remains.

Question 14

Arguments by Elimination Ex:

Answer 14

It is A, B, or C
It is not A
It is not B
Therefore, it is C

Question 15

Disjunctive syllogism

Answer 15

-argument by elimination

-Either A or B
Not A
Then, B

Question 16

Arguments Based on Mathematics

Answer 16

Depend on mathematical or geometric equations to generate conclusions.

Question 17

Arguments Based on Mathematics Ex:

Answer 17

Chris is 6’2”
I am 5’6”
Therefore, Chris is 8” taller than me

Question 18

Arguments of Definition

Answer 18

-The conclusion is true because it is based on a key term or essential attribute in a definition.

Question 19

Arguments of Definition Ex:

Answer 19

Paulo is a father
All fathers are men
Therefore, Paulo is a man

Question 20

Hypothetical Syllogisms

Answer 20

• A form of deductive argument

- contains two premises, at least one of which is a hypothetical or conditional if…then statement.

Question 21

patterns of hypothetical syllogisms

Answer 21

• Modus ponens (affirming the antecedent)
• Modus tollens (denying the consequent)
• Chain arguments

Question 22

Modus Ponens

Answer 22

-Affirming the antecedent

If A, then B.
A
Therefore, B

Question 23

Modus Ponens Valid ex:

Answer 23

If Barack Obama is president, then he was born in the US.
Barack Obama is president.
Therefore, he was born in the US.

Question 24

Modus Ponens InValid ex:

Answer 24

If Oprah Winfrey is president, then she was born in the US.
Oprah Winfrey was born in the US.
Therefore, Oprah Winfrey is president.
Fallacy of affirming the consequent

Question 25

Modus Tollens

Answer 25

-(Denies the consequent)

If A, then B
Not B
Therefore, not A.

Question 26

Modus Tollens valid Ex:

Answer 26

If Michelle is a physician, then she has graduated from college.
Michelle did not graduate from college.
Therefore, Michelle is not a physician.

Question 27

Modus Tollens invalid Ex:

Answer 27

If Michelle is a physician, then she has graduated from college
Michelle is not a physician.
Therefore, she did not graduate from college.
Fallacy of denying the antecedent

Question 28

Chain Arguments

Answer 28

Made up of three conditional propositions: (two premises and one conclusion) linked together

If A, then B. (1)
If B, then C. (2)
Therefore, A, then C. (3)

If A, then B. (1)
If B, then C. (2)
If C, then D. (3 )
Therefore, A, then D. (4)

Question 29

standard form:

Answer 29

the conditional promise first and the conclusion last.

Question 30

Categorical Syllogisms

Answer 30

• categorizes or sort things into specific classes.
• conclusion, 2 premises, and 3 terms (each of which occurs exactly twice in 2 of the 3 propositions.)

Example: “All tigers are cats. Some mammals are not cats.
Therefore, some mammals are not tigers.”

Question 31

S term

Answer 31

subject

Term that appears first in the conclusion.

Question 32

Minor premise

Answer 32

premise in which the S term appears.

Question 33

P term

Answer 33

Predicate

Appears second in the conclusion.

Question 34

Major premise:

Answer 34

: the premise in which the P term appears

Question 35

M term:

Answer 35

middle term, major and minor term.

Occurs only in the two premises

Question 36

Hypothetical Syllogisms validity

Answer 36

If the form is valid and the premises are true—> the conclusion is necessarily true.

Question 37

Universal quant.

Answer 37

• “All,” “Every,” “No,” “None”

- All S are P and no S are P —> universal propositions.

Question 38

particular quant.

Answer 38

• refers only to some members of the class

- some S are P and some S are not P