Here is the simplest term I use to describe what a scientific theory is to a creationist that is used to blowing hot air out of his butthole. When a theory is recognized and confirmed, scientists are 99.99999999% sure it is true. To say that since-evolution-is-just-a-theory-therefore-it-can't-be-taken-seriously is like saying since-gravity-is-just-a-theory-then-things-will-sometimes-fall-upward.
The Laminator