|
Soundness - Definition and Overview |
|
|
|
|
A logical argument is sound if and only if
- the argument is valid
- all of its premises are true.
A proof procedure (e.g. natural deduction) for a logic is sound if it proves only valid formulas (also tautologies).
Sound Arguments
Suppose we have a sound argument (in this case a syllogism):
- All men are mortal.
- Socrates is a man.
- Therefore, Socrates is mortal.
The argument is valid and since the premises are in fact true, the argument is sound.
The following argument is valid but not sound:
- All animals can fly.
- Pigs are animals.
- Therefore, pigs can fly.
Since the first premise is actually false, the argument, though valid, is not sound.
|
|
Example Usage of Soundness |
 |
ToryOutcast: At the york tory alumni dinner. So much Soundness in one room. difficult to cope with such competition |
 |
Fabalish: Being well consists of thinking well...treating yourself & others well..and feeding your Spirit...Mind..& Body *Soundness in all three* |
 |
ks91020: [truth-or-dare]
Only Soundness of mind can make it possible for you to laugh. True or false?
-or-
Make a hilarious song title. #t_d |
|