An argument is valid if and only if: At least one premise is true, and the conclusion is also true.

An argument is sound if and only if: All of its premises are true.

An argument is sound if and only if: It's valid and at least one of its premises is true.

An argument is valid if and only if: If the conclusion is true, then all the premises must be true.

An argument is valid if and only if: If all the premises are true, then the conclusion must be true.

An argument is valid if and only if: All the premises are true, and the conclusion is also true.

An argument is sound if and only if: It's valid and all of its premises are true.

An argument is valid but not sound if and only if: It's valid and at least one of its premises is false.

A shape is a triangle if and only if: It has three sides and its angles total 180 degrees.

All valid arguments have true conclusions.

Logic is the study of argument structure, not of truth.

Some invalid arguments have true premises.

All valid arguments are sound.

Some valid arguments have false premises.

Every invalid argument has at least one false premise.

No sound arguments have false conclusions.

All sound arguments are valid.

To determine if an argument is valid you must first know whether or not the premises are true or false.

Some sound arguments are invalid.

No invalid arguments have true conclusions.

Every valid argument has a true conclusion.

No invalid arguments are sound.

Every valid argument has at least two premises.

All valid arguments have at least one true premise.

Some valid arguments are sound.

The following argument is valid:

The moon is made of lime jello.
The moon is made of lime jello.

The following argument is valid:

Apollo is a god.
Flipper is a porpoise.
Apollo is a god and Flipper is a porpoise.

The following argument is valid:

Zeus is a god and strawberry is a flavor of jello.
Zeus is a god.

Some arguments are false.

Some arguments are true.

No premises are valid.

Some premises are sound.