Because it doesn't contain two things that are mutually incompatible.
The two points of a paradox must be unable to both be true simultaneously, but both seem to be true as they stand alone. "para" means "beyond" and "dox" means "thought" or "opinion"

Ok, best simple example I know of, "what happens if Pinocchio says 'my nose will grow now' ? "

Everyone one knows Pinocchio's nose grows if he lies. And the statement "my nose will grow now" can either be true or a lie. But if it's a lie, his nose will grow because he's lying, but that would make the statement true. The two parts are mutually incompatible.
( the mighty badger Aphrodite, on a bar stool, by your side, Thu 21 Mar 2013, 12:12, Reply)