Concepts

Multiple Choice: Click on the correct answer and the page will jump forward to the next problem.

1. A PL sentence P is logically true in PL if and only if ...

a. P is not false on any truth value assignment. b. P is not true on any truth value assignment. c. P is not false on any interpretation. d. P is not true on any interpretation.

2. A PL sentence P is logically false if and only if ...

a. ~P is logically true.
b. P is not logically false.
c. P is not logically indeterminate.

3. If two PL sentences P and
Q are logically equivalent, then ...

a. there is no interpretation on which one of P and Q is true while the other is false.
b. an argument with P amongst its premises and Q as its conclusion is valid in PL.
c. if P is logically true, Q is also logically true.
d. All of the above.

4. If an argument has either a logically inconsistent set of premises or a logically true conclusion, then ...

a. that argument is valid.
b. that argument is invalid.
c. Neither of the above.

5. If P is logically false, then ...

a.
an argument with P as conclusion must be invalid.
b.
a set including P must be inconsistent.
c.
Both of the above. d.
Neither of the above.