Week 4 Quiz

A restaurant kitchen's rule (illustrative) reads: "If the oil light is red, then the oil is too hot to use." Which claim is the consequent of this conditional?

Select one.

• The oil light is red.
• The oil light is not red.
• The oil is too hot to use.
• The rule is posted above the fryer.

In exactly which situation is a conditional of the form "if P, then Q" false?

Select one.

• When P is true and Q is false.
• When P is false and Q is true.
• When P and Q are both false.
• Whenever P is false, whatever Q is.

A campus parking sign (illustrative) says: "You may park in Lot C only if you display a permit." Which "if, then" sentence says the same thing?

Select one.

• If you display a permit, then you may park in Lot C.
• If you may park in Lot C, then you display a permit.
• If you do not display a permit, then you may park in Lot C.
• If you may not park in Lot C, then you do not display a permit.

Which form has the pattern "if P, then Q; not Q; so not P"?

Select one.

• Denying the antecedent
• Modus ponens
• Affirming the consequent
• Modus tollens

An argument (illustrative) reads: "If it rained overnight, the soccer field is wet. The soccer field is wet. So it rained overnight." Which verdict is right?

Select one.

• Valid, because on most mornings when the field is wet, it really did rain overnight.
• Valid, because it follows the same pattern as modus ponens, from a conditional to a claim.
• Invalid, because a sprinkler morning makes both premises true and the conclusion false.
• Invalid, because its first premise, about rain and the field, is false.

An argument (illustrative) reads: "If it rained overnight, the soccer field is wet. It did not rain overnight. So the soccer field is not wet." Which description fits it?

Select one.

• Denying the antecedent, invalid, because it denies the if-part and the sprinklers refute it.
• Modus tollens, valid, because its second premise denies part of the conditional with a not.
• Modus ponens, valid, because it starts from a conditional and one of the conditional's parts.
• Disjunctive syllogism, valid, because it rules out one option and concludes the other.

Which sentence is equivalent to "If it rained overnight, the soccer field is wet"?

Select one.

• If the soccer field is wet, it rained overnight.
• If it did not rain overnight, the soccer field is not wet.
• If it did not rain overnight, the soccer field is wet.
• If the soccer field is not wet, it did not rain overnight.

A course listing (illustrative) says: "You can register for the course only if you passed the prerequisite." Which statement about passing the prerequisite is right?

Select one.

• It is sufficient for registering, so anyone who passed can register.
• It is necessary for registering but not sufficient, since an open seat is also needed.
• It is both necessary and sufficient for registering.
• It is neither necessary nor sufficient, since the listing names no other condition.

A teammate (illustrative) says: "Look, the field's soaked. If it rained overnight, the field would be soaked, so it must have rained overnight." Which claim is the teammate's conclusion?

Select one.

• If it rained overnight, the field would be soaked.
• The field is soaked.
• It rained overnight.
• The teammate looked at the field.

In the argument-form set and its truth-table check, the four valid forms are modus ponens, modus tollens, hypothetical syllogism, and disjunctive syllogism, and the two invalid forms are affirming the consequent and denying the antecedent. How many forms does the set hold in all?

Select one.

• 4 forms
• 5 forms
• 8 forms
• 6 forms