Creationist: I believe in God.
Scientist: Seriously? That's ridiculous. It's a fable created to make up for a gap in human understanding. I only believe in things that can be proven.
Creationist: Okay, explain dark matter to me.
Scientist: It's this stuff that makes up the vast majority of the universe. I mean, I think it does. I'm not really sure what it's made of of, or what relation it has to other matter. Or if I'd be able to identify it if I saw it. I can't tell you its properties, how it is created, whether what we have exists from the creation of the universe or if there is some mechanism that continues to process it, but we have no other explanation that fits in with everything else we think we know, so its existence must be real.
Creationist: So it's a fable created to make up for a gap in human understanding?
Scientist: No, it's science!