Cooper: You're a scientist, Brand.
Brand: So listen to me when I say love isn't something that we invented. It's observable. Powerful. It has to mean something.
Cooper: Love has meaning, yes. Social utility, social bonding, child rearing...
Brand: We love people who have died. Where's the social utility in that?
Brand: Maybe it means something more - something we can't yet understand. Maybe it's some evidence, some artifact of a higher dimension that we can't consciously perceive. I'm drawn across the universe to someone I haven't seen in a decade who I know is probably dead. Love is the one thing that we're capable of perceiving that transcends dimensions of time and space. Maybe we should trust that, even if we can't understand it.