Sometimes, during those late hours when the TARDIS's lights are dimmed, when Rory and Amy are sleeping and he's slept for the hour or so he needs, The Doctor's thoughts drift.
Drift through the constellations and around planets and across the great arcs of stars, to the great vast expanse, full of emptiness, that was once the constellation of Kasterborous.
Gallifrey always burned like a beacon in his mind, a giant star of life and thoughts and energy pulsing and vibrant and so bright that if he closed his eyes and reached out it was like he was almost there.
He can't do that anymore.
Can't even pinpoint where it had been with his mind, because light is so much easier to see than darkness. You can only see into darkness like that when you're close, orbiting stars in the neighbouring constellations and feeling your mind reaching out and grasping and finding nothing.
He dreams of Gallifrey too, sometimes, and in his dreams doesn't see academics in their ivory towers, tutting at him, or his family so full of disappointment because he'd been their chance to become a good, upstanding House and he'd let them all down.
No, he doesn't see that. Sometimes he sees his family home, smells the red grass from the nearby hills, tastes the meals whose names he never asked for, sees signs written with hexagrams and circles and hears the chatter of Gallifreyan and then he wakes up feeling cold and empty and so, so alone, and has to draw his mind back into himself because it's spread out as far as it could, just searching for home.
Sometimes, just sometimes, when everything goes wrong and he's left to his own thoughts, he thinks of what would've happened if he'd just tried harder.
That maybe he could have found another way, if he was smarter if he was better if he was a proper Time Lord he would have been able to find a way out that wouldn't have consigned his race to the proverbial scrapheap.
And sometimes his thoughts betray him even more and he thinks back to the day that they almost returned and finds himself wishing, hoping that maybe if they had come back he'd have found a way from stopping them hurting people, found a way to bring the council back to it's dry sensibilities and then he wouldn't be the last one, he wouldn't feel so empty and cold and alien.
He shouldn't feel this way.
Because some nights he still sees the war, the burning skies, the Nightmare Child, the hundreds of horrors unleashed on an unsuspecting universe by a race with too much power, madmen fighting madmen.
He was the one who used the Moment.
It's his fault they're gone.
He shouldn't have an entire database used as a dictionary for words so he won't forget them, or notebooks filled with scratched sentences and notes on grammar, or journals with every detail of home that springs into his mind.
Because once he's gone they will be too.
All that's left is his memories and he knows that all he's doing is making another Matrix, a repository so that when he's gone maybe somebody else will know that the Timelords were at their heart just Gallifreyans, not Gods or legends.
He should just forget about them, because he has his own new life, he has River who's got at least some semblance of understanding, and it was his own fault it ended up this way but.
But.
But he'll never be able to speak, truly speak Gallifreyan again, with the mental lilts and inflections and modifiers, never be able to have a conversation using images and emotions without even having to speak, never be able to truly open his mind and have it answered by anything but cold dead silence.
He's the last of the Timelords, the Oncoming Storm, the Timelord Victorious. The Lonely God.
But he knows he's just a Lungbarrow upstart with a stolen Type-40 that was going to be decommissioned anyway, who was so lucky to be let in the Academy, who constantly asked the other Deca for help, who was an exile once but a President once too, who is just so unrepresentative of what Gallifrey was, of what the Time Lords were it would make him laugh if he really thought about it.
But he doesn't think about it.
Not at all.