Alicia: How big is the universe?
Alicia: How do you know?
Nash: I know because all the data indicates it's infinite.
Alicia: But it hasn't been proven yet.
Alicia: You haven't seen it.
Alicia: How do you know for sure?
Nash: I don't, I just believe it.
Alicia: It's the same with love I guess.
From »A beautiful mind«