As far as I understand it, causality is just the relationship between cause and effect. If I'm right, saying it tries to avoid paradoxes is like saying gravity acts whenever someone falls off a cliff to prevent them from flying.

That was a somewhat anthropomorphic allusion to the Novikov self-consistency principle. But yes, it is.

Fortunately, I don't see any situation in this fic where Twilight would even want to use time travel.

Fair enough.

EDIT:

If I really needed to explain away time travel in this fic, I'd probably have a future Twilight show up and say "Whatever you do, do NOT use time travel. I don't care how bad it is. Even if Equestria is going to be destroyed if you don't. DO. NOT. MESS. WITH. TIME."

You realize the canonical example of time travel was a stable loop, right? As was that pinkie-sense business.