"Saw the world, wrote and wrote and wrote. She never thought her books were any good, though." You asked, noted, suggested that she spent the years wondering. Donna, you asked him. And he said, "Thing is, I don't think she ever quite forgot. All the stuff her imagination could use..." But far in a future library, look at the copyright page: facsimile edition, published in the year Five Billion! People never stop reading them. Christie is the best-selling novelist of all time, and she never knew. But then no one knows how they're going to be remembered: All you can do is hope for the best. Maybe that's what kept her writing: the same thing that keeps him traveling. Traveling onwards: every single oracle tells the truth.
Then came Moffat: a beautiful, ancient building that was also a girl, and a chance at love for the Doctor. You were kind, and you were considerate, and there was a whole hour about River Song. I like River Song. She deals with his complete freeze really well, deals with your future really well, and in the middle she uses screwdrivers and squareness guns with aplomb. And she dies. And because the Doctor loves her, or trusts that he will love her one day, and likes her well enough now, he takes her out of death and into light.
I like her because I think she represents a point in time in which the Doctor becomes enough like us, and we become enough like him, that the veil hangs not quite so heavy. That we can play with those screwdrivers and what they mean, without risking death or loss of memory. It's not given, to men and women, to love Gods. Not now. We can't see what they see, and they have a devil of a time seeing what we see. I think Rose taught him to be a man, and you taught him what that means, but I don't think he can ever love, with both his hearts, until that day.
In broad terms, the entire process of anima development in a male is about the male subject opening up to emotionality, and thus broader spirituality, by creating new paradigms as he encounters/projects new forms of femininity. The first is Eve, the Maiden: the emergence of the object of desire; has the troubling habit of simultaneously generalizing all females as evil and powerless. If you haven't met a guy stuck in this place... Well, trust me. You have. I don't know what else to say.
That's where Rose started. She fell in love with him, and he fell in love with her. But only with one heart. It's the heart the Master could never break, and it's the heart that keeps him tied to Earth, now Gallifrey's gone. Not to get all mass-market paperback on you, but just imagine for a second there was a person, both divine and human. With all working parts. Sent from the heavens, to remind us of our redemption. And maybe he met a girl, they say, and maybe they fell in love. When Rose goes back home to the last time, that last painful time on Bad Wolf Bay, she's not getting cheated: she's taking home the part of him that she loves. The only part that can love her back. A whole man, albeit with a Chiswick accent, but one who knows nothing of divinity, and everything to do with war. The man she fell in love with.