Eureka, Season 1

Carter:
Henry, You don't believe in aliens, do you?

Henry:
No, I believe in Occam's Razor. It's the basis for methodological reductionism.

Carter:
... Oh, Yeah. So... still dizzy...

Henry:
Okay, so, given two equally predictive theories, you choose the one that has fewer assumptions. So, a tree falls after a storm. The first hypothesis holds that the tree was blown over by the storm. The second - rival hypothesis - claims that the storm forced an alien spaceship to cash into the tree. See?

Carter:
Y-no.