Unit 1

Question 1

Logic

Answer 1

Study of methods for evaluating arguments

Question 2

Argument

Answer 2

set of statements, one of which, called the conclusion, is affirmed on the basis of the others, which are called the premises

Question 3

Statement

Answer 3

sentence that is either true or false

Question 4

True Values

Answer 4

truth and falsehood are the two possible outcomes

Question 5

Premises

Answer 5

the statements on the basis of which the conclusion is affirmed

Question 6

Conclusion

Answer 6

the statement that is affirmed on the basis of the premises

Question 7

Valid argument

Answer 7

it is necessary that if the premises are true, then the conclusion is true

Question 8

Invalid argument

Answer 8

It is not necessary that if the premises are true, then the conclusion is true

Question 9

Sound Argument

Answer 9

It is valid and all its premises are true

Question 10

Unsound Argument

Answer 10

Is an argument that either is invalid or has at least one false premise

Question 11

deductive logic

Answer 11

Part of Logic that is concerned with tests for validity and invalidity

Question 12

Substitution Instance

Answer 12

an argument that results from uniformly replacing letters with terms in an argument

Question 13

Argument form

Answer 13

pattern of reasoning

Question 14

Counterexample

Answer 14

Is a substitution instance whose premises are well known truths and whose conclusion is a well-known falsehood

Question 15

Antecedent

Answer 15

the if-clause of a conditional

Question 16

Consequent

Answer 16

the then-clause of a conditional

Question 17

logically equivalent

Answer 17

two statements are this if each validity implies the other

Question 18

Modus Ponens

Answer 18

If A, then B.
A.
Therefore, B.
means “the mode of positing” (sometimes called the way of affirmation) because the second premise posits the antecedent of the conditional (first) premise.

Question 19

Modus Tollens

Answer 19

If A, then B.
Not B.
Therefore, not A.
means “the mode of removing” (sometimes called “way of denial”) because the second premise removes or denies the truth of the consequent of the first (conditional or major) premise.

Question 20

Negation

Answer 20

Denial

Question 21

Fallacy of denying the antecedent

Answer 21

If A, then B.
Not A.
Therefore, Not B.
invalid and is confused with modus tollens

Question 22

Fallacy of affirming the consequent

Answer 22

If A, then B.
B.
Therefore, A.
invalid and is confused with modus ponens

Question 23

hypothetical syllogism

Answer 23

If A, then B.
If B, then C.
Therefore, If A, then C.
In Greek, “syllogism” means “to reason together.”
The argument is called “hypothetical” because it involves only conditional statements.

Question 24

disjunctions

Answer 24

statements of the form “either A or B”

Question 25

disjunctive syllogism

Answer 25

Either A or B.
Not A.
Therefore, B.
The two parts of the major premise are called “disjuncts.”
There are two senses of “or.”
The inclusive sense basically means “at least one of A or B (or both).”
The exclusive sense means “either A or B (but not both).”

Question 26

constructive dilemma

Answer 26

Either A or B.
If A, then C.
If B, then D.
So, either C or D.
combines both conditional and disjunctive statements

Question 27

Strong Argument

Answer 27

It is probable (but not necessary), that if the premises are true, then the conclusion is true

Question 28

Weak argument

Answer 28

It is not probable that if the premises are true, then its conclusion is true

Question 29

Arguments from authority

Answer 29

R is a reliable authority regarding S
R sincerely asserts that S.
So S

Question 30

Arguments from analogy

Answer 30

Object A is similar to object B in certain relevant respects
B has property P
So A has property P also

Question 31

Cogent argument

Answer 31

any argument that is both strong and has only true premises

Question 32

Uncogent argument

Answer 32

is either weak or strong but has one or more false premise.

Question 33

Inductive logic

Answer 33

part of logic that concerns tests for strength and weakness