Evaluating Deductive Argument

If a deductive argument is sound, then:

• It must be valid

• It must be invalid

• It could be valid or invalid

If a deductive argument is invalid, then:

• At least one premise must be false.

• all the premises must be false.

• all the premises must be true

• not enough info to determine.

If a deductive argument is valid, then:

•   it must be sound.

• it must be unsound

• it could be sound or unsound

If a deductive argument has a false premise, then:

• it must be invalid but may or may not be sound

• it must be unsound but may or may not be valid.

• it must be both invalid and unsound

• none of the above

  If a deductive argument is invalid, then:

• it must be sound

• it must be unsound

• it could be sound or unsound

If a deductive argument is sound, then:

• it must be valid but may not have all true premises.

• it must have all true premises but may not be valid

• it must be valid and have all true premises.

If a deductive argument’s conclusion is true:

• then the argument must be valid

• then the argument must be invalid.

• then the argument could be valid

  or invalid

If a deductive argument’s conclusion is false:

• then the argument must be valid.

• then the argument must be invalid.

• then the argument could be valid

              or invalid

Deductive arguments sometimes take a form called a syllogism.

• True

• False

A good method for evaluating an argument is figuring out whether the
the conclusion is correct.

• True

• False