Logic 8

Question 1

Valid

Answer 1

A syllogism is valid if and only if the premises imply the conclusion.

Question 2

Sound Syllogism

Answer 2

A sound syllogism is valid and has true premises

Question 3

Counter-example

Answer 3

A counterexample to a syllogism is a syllogism of the same form as the original, but with obviously true premises and an obviously false conclusion, in order to show the original to be invalid.

Question 4

Distributed Term

Answer 4

A distributed term is a term that, within a statement, refers to all members of its category.

Question 5

Five Rules for Testing the Validity of Syllogism

Answer 5

Rule 1: In at least one premise, the middle term must be distributed.

Rule 2: If a term is distributed in the conclusion, it must also be distributed in its premise.

Rule 3: A valid syllogism cannot have two negative premises.

Rule 4: A valid syllogism cannot have a negative premise and an affirmative conclusion.

Rule 5: A valid syllogism cannot have two affirmative premises and a negative conclusion.