The Big Bang Theory2007

Sheldon:
I really think we should examine the chain of causality here.

Leonard:
Must we?

Sheldon:
Event A: A beautiful woman stands naked in our shower. Event B: We drive halfway across town to retrieve a television set from the aforementioned woman's ex-boyfriend. Query: On what plane of existence is there even a semi-rational link between these events?

Leonard:
She asked me to do her a favor, Sheldon.

Sheldon:
Ah, yes. Well, that may be the proximal cause of our journey, but we both know it only exists in contradistinction to the higher-level distal cause.

Leonard:
Which is?

Sheldon:
You think with your penis.