|“||You can't rewrite history! Not one line!||”|
"Time can be rewritten" is a running theme of the Moffat era. It represents his belief that a time traveler, here serving as the metaphor for the author of a story, has both the right and the responsibility to "make sure it's a good one". Time can be rewritten, but Fixed points in time cannot. It's Timey-Wimey.
- RIVER: There's nothing you can do.
DOCTOR: You can let me do this.
RIVER: If you die here, it'll mean I've never met you.
DOCTOR: Time can be rewritten.
RIVER: Not those times. Not one line. Don't you dare. It's okay. It's okay. It's not over for you. You'll see me again. You've got all of that to come. You and me, time and space. You watch us run.
~Remember when we were all wondering who she was? Good times...
- DOCTOR: And if you read ahead and find that Rory dies? This isn't any old future, Amy, it's ours. Once we know what's coming, it's fixed. I'm going to break something, because you told me that I'm going to do it. No choice now.
AMY: Time can be rewritten.
DOCTOR: Not once you've read it. Once we know what's coming, it's written in stone.
~Rory's tombstone is literally in shot when all this is going on.
- DOCTOR: Every point in time has its alternative, Sarah. You've looked into alternative time.
LAURENCE: Fascinating. Do you mean the future can be chosen, Doctor?
DOCTOR: Not chosen, shaped. The actions of the present fashion the future.
LAURENCE: So a man can change the course of history?
DOCTOR: To a small extent. It takes a being of Sutekh's almost limitless power to destroy the future.
~Sure, complicate things, Doc, why don'tcha.
- DOCTOR: But this is fixed. This is a fixed point in time.
RIVER: Fixed points can be rewritten.
DOCTOR: No, they can't. Of course they can't. Who told you tha--
~River Song destroys the universe. Eh, who cares, not like it was any good anyway.