What is Valid?
1.
A word coined by Santo Cilauro on The Panel (Australian talk show). It can many anything that's hip, unexpectedly good, or used in the place of bravo.
Did you see that brilliant movie last night?
Yeah it was valid! Valid I say!
2.
Something that is very cool, exciting or of a high standard.
1. Nice boarding move - valid!
2. Man, how valid was that movie?
3. Check out the wheels on that beast - now that's valid!!
3.
A property of an argument in logic that preserves the truth, in which there is a neccessary agreement between the premises (assuming that they are true) and the conclusion; that one must undoubtedly arrive at the conclusion. It is not possible for the premises to be true, and the conclusion false. Note that validity is not the same as soundness, which is a valid argument that has all true premises.
Valid:
If I am in Paris, then I am in France; I'm in Paris, therefore I am in France. If I am not in France, then I am not in Paris; oh look, I'm in New York; therefore I must not be in France.
Invalid:
If I am in France, then I am in Paris; Woah! I'm in France, I must be in Paris...BUZZ! I'm actually in Bordeaux.
Either 2 plus 2 equals 22, or Santa Clause is real; but 2 plus 2 does not equal 22; so Santa Clause is real.
Unsound but Valid:
All mammals are cats (false, but assuming it is true); All cats are animals; So all mammals are animals.
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