Lost, Season Four

Daniel Faraday:
I think Eloise's brain short-circuited. The jumps between the present and the future eventually, she eventually, she couldn't tell which was which. She had no anchor.

Desmond:
What do you mean, "anchor"?

Daniel Faraday:
Something familiar in both times. All this, see all this is all variables. It's random; it's chaotic. Every equation needs stability, something known. It's called a "constant." Desmond, you have no constant. When you go to the future nothing there is familiar. So if you want to stop this, then you need to find something there, something that you really, really care about, something that also exists back here in 1996.

Desmond:
This constant, can it be a person?

Daniel Faraday:
Yeah, maybe. But you have to make contact. Didn't you say you were out on a boat in the middle of nowhere? [Desmond picks up a phone and begins dialing] Uh, who are you calling?

Desmond:
Calling my bloody constant.