Exam 1: Basic Concepts

A hypothetical syllogism has the following form:

All sound arguments have

A counterexample to an argument form is a substitution instance whose

If an argument is strong, then

Use a counterexample to show that the following argument is invalid. (Remember, it is usually best to use terms-or statements-whose interrelations are well known.) "No people whose attention is easily distracted while they are working are people who are keenly interested in their work. No successful people are people whose attention is easily distracted while they are working. So, all successful people are people who are keenly interested in their work."

All strong arguments have

If the following argument is an instance of one of the "famous" argument forms, name the form and indicate whether the form is valid or invalid; if the argument is NOT an instance of one of the "famous" forms, simply write "unnamed form." Either we should launch a preemptive strike or else we should adopt a policy of containment. We should not launch a preemptive strike. Therefore, we should adopt a policy of containment.

A category statement asserts some relation between sets or collections of things.

Every argument intends to guarantee the truth of its conclusion.

A term is

An invalid argument can have false premises and a

Use a counterexample to show that the following argument is invalid. (Remember, it is usually best to use terms-or statements-whose interrelations are well known.) "If Bob loves his country, Bob votes. Bob does not vote. It follows that Bob loves his country."

If the following argument is an instance of one of the "famous" argument forms, name the form and indicate whether the form is valid or invalid; if the argument is NOT an instance of one of the "famous" forms, simply write "unnamed form." Either terrorists are wicked or terrorists are freedom fighters. Terrorists are wicked. It follows that terrorists are not freedom fighters.

Use a counterexample to show that the following argument is invalid. (Remember, it is usually best to use terms-or statements-whose interrelations are well known.) "All business executives are active opponents of increased corporate taxes, for all active opponents of increased corporate taxes are members of the chamber of commerce, and all members of the chamber of commerce are business executives."

Identify the following as valid, invalid, strong, or weak: "All men are mortal. Socrates is mortal. ∴ Socrates is a man."

A good counterexample employs well-known truths for its premises and conclusion.

All sentences are statements.

Use a counterexample to show that the following argument is invalid. (Remember, it is usually best to use terms-or statements-whose interrelations are well known.) "Churchill was a politician or a painter. Churchill was a politician. So, Churchill was not a painter."

Identify the following as valid, invalid, strong, or weak: "No one has ever run a three-minute mile. ∴ No one ever will."

Identify the following as valid, invalid, strong, or weak: "Either Williams will win the election or Jarboe will win it. If Williams wins the election, then recycling will become mandatory. If Jarboe wins the election, then universal garbage collection will become mandatory. So, either recycling or universal garbage collection will become mandatory."