CSI: Crime Scene Investigation, Season 8

Rev. Rhodes:
Mr. Grissom...do you believe in a separate, living evil?

Grissom:
You're a primitive man on the Savannah. You see something move out of the corner of your eye. You assume it's a hyena. You run, you live. If you assume it's the wind and you're wrong, you die. We have the genes of the ones who ran. We're genetically hard-wired to believe living forces that we cannot see.

Rev. Rhodes:
The Devil's sliest trick is making us believe he isn't real. But call his name loud and long enough, [knocks on the table four times] guess who comes knockin' on your door?

Brass:
Usually guys like you.