Perhaps the most compelling possibility: could River Song be the Tardis? Well, more specifically, the intelligence within the Tardis. We know that at the end of her life, as we see it, River becomes an intelligence in the galaxy’s most bodacious computer in Silence in the Library. River herself refers to the Tardis as “she” in The Pandorica Opens, and certainly the Doctor has before. It would explain her comment that she and the doctor went to the “end of the universe” together. When at the end of the universe in Utopia, the Doctor commented he’d never been there before and that even the Time Lords had never ventured that far in time, so we would expect that to be his one trip there. But it was only the Doctor, Captain Jack and Martha Jones….and the Tardis, of course.
The Doctor and the Tardis have always seemed to have a tumultuous love affair, and yet they are inseperable.
In The Pandorica Opens, when River sees the “raggedy doctor” figurines in Amy’s house she says, in a way that at first blush sounds like a wifely comment, “I don’t know why I ever let you out.” Consider that statement if she turns out to be the Tardis.
Her diary looks like the Tardis.
She was trapped in the Tardis when it exploded. Could this have created a paradox where she took human form, maybe even because of the thoughts and memories of Amy Pond, and exists alongside the Tardis? Perhaps the mechanism for why the Tardis is in human form has yet to be revealed. Then again, let’s never forget the male voice we hear (and she hears) in the Tardis in The Pandorica Opens saying, “silence will fall.” If River is in fact the Silence (which makes sense with her first appearance, Silence in the Library) was this foretelling the death of the Tardis in the explosion? (Is the male voice Omega? Perhaps the trickster figure, the Dream Lord, from Amy’s Choice? Time will tell.)
Can this notion of River being the Tardis be applied to every clue she’s given us? Discuss.