Logic test 1

Valid Arguement:

• An argument where it is impossible for the premises to be true and the conclusion false

• a valid argument with true premises

• a sentence which is true in every row of a truth table

• true in all possible ways

Sound Argument

• an argument where it is impossible for the premises to be true and the conclusion falls

• a valid argument with true premises

• true in all possible worlds

• an argument where two sentences are tautologically equivalent when the truth tables for the statements are identical

The following is an example of...

P1 Jackie's baby is a turtle or a frog

P2 Jackies baby is not a frog

C. Jackies baby is a turtle.

• Valid Argument

• Sound Argument

The following is an example of...

P1 Jackies baby is a girl or boy

P2 Jackies baby is not a boy

C Jackies baby is a girl.

• Sound Argument

• Valid Argument

Logical Truth:

• true in all possible worlds

• must always be true

• a sentence which is true in every row of a truth table

Logical Necessity:

• could be true

• Must always be true

• when the truth tables for the statements are identical

logical possibility:

• could be true

• logical possibility is not a physical possibility

• logical possibility is a physical possibility

tautology:

• a sentence which is true in every row of a truth table

• A statement that is always true.
• A statement that is always false.
• the truth tables for the statements are identical

Tautological Equivalence:

• when the truth tables for the statements are identical

• Q is equivalent of P if when P is true, Q is always true as well

• a sentence which is true in every row of a truth table

Tautological Consequence:

• Q is a tautological consequence of P if when P is true, Q is always true as well

• Q is a tautological consequence of P if when P is true, Q is false

• P is a tautological consequence of Q if when Q is true, P is always true as well

• Q is not a tautological consequence of P if when P is true, Q is always true as well