Since there's no Doctor Who Christmas Special this year, let's look back at last year's Christmas Special 'Twice Upon a Time'. I was watching it again and noticed some themes I'd missed before.
To recap: the Doctor has died. He refuses to regenerate. He has lived so long and loved and lost so much that he doesn't want to throw it all away to become a new person. The TARDIS has taken him where he needs to be to come to terms with his life and his death. Who should he meet but his younger self, the First Doctor, also fresh from his final adventure and refusing to regenerate. The story is the 12th Doctor's final odyssey as he finds a reason to finally consent to regenerate and become a new person and begin a new life.
Steven Moffat layered a lot of literary and philosophical themes throughout his run on Doctor Who, and only got more ambitious during Peter Capaldi's three-season stint as the 12th Doctor – with "Twice Upon a Time" being Moffat and Capaldi's last hurrah. The 12th Doctor's story was done in the season finale story "The Doctor Falls" and the Christmas Special is really an extended coda for him.
You can look at "Twice Upon a Time" as a Buddhist parable about a man who's already died, wandering Purgatory and coming to terms with his life – meeting his past self, the First Doctor, grappling with the weight of his mortality – and finally forgiving himself, letting go of all his baggage before he agrees to be reincarnated into a new life to begin the struggle all over again.
Along the way, he finally finds forgiveness and redemption for himself, and forgiveness and redemption had been recurring themes throughout Capaldi's three seasons. By the end of his run, the people around the Doctor, including Nardole and Missy, found redemption. Now it was down to the Doctor to find his own redemption. It's apt that there's no evil plot or villain in this story. The Doctor's antagonist here is his own guilt and self-doubt, his wariness in the prospect of continuing.
Although this is a Christmas Special, the Doctor does not go to heaven or hell when he dies as in Judeo-Christian lore. Instead, he regenerates into a new person – a form of reincarnation. I don't know if Moffat was conscious of the Buddhist motif so much as the themes of forgiveness, redemption and letting go. Buddhism teaches the need to let go of ego, of emotional baggage, of guilt and hate, of desires and needs, and that is the Doctor's journey in "Twice Upon a Time".
This begins the Doctor's look back on his life. This is Moffat's version of the Doctor's life flashing before his eyes before he dies for good. He literally gets to meet his younger self. They meet a soldier from the First World War who is also on the verge of death. The themes start to fall into place. Doctor Who has always been a show about death. It often teaches children about death and loss, but what pushes Moffat and Capaldi's run further is the exploration of how one faces death, and this special is the final cap on that theme.
When the Doctor sees his life and what he's done in his various incarnations, this is part of the parable of the dying man looking back on his life. He feels guilt about the things he's done, but later admits to the good he does as well. He has to convince his younger self that his life is worth continuing with, a balancing of the good and bad he goes on to do.
The Doctor goes to a necropolis – a place of death – to look for more answers. Again, this is part of the parable. This is the part of the story where the hero has to go to the Underworld, and who should be the lord of this Underworld but a rogue Dalek whose life the Doctor had previously saved. This Dalek has since found its own form of redemption by waging war on the rest of the Daleks. This has shades of It 's a Wonderful Life where the Doctor has made the people he encountered better. And the First Doctor and Bill discuss the universal question of good and evil. Bill is the angel guiding the Doctor – both of him – on this journey towards answering why he should live on. Moffat likes to allude to many literary references in his scripts, lightly, without hammering them too hard. There are echoes of Dante's Inferno, Dickens, and Shakespeare here.
"It's not actually an evil plan… I don't know what to do if it's not an evil plan."
When the Doctor discovers the plot to take people throughout history before their deaths to preserve their memories is not evil but a humane act of mercy and remembrance, this is the start of his letting go. He realises he doesn't need to fight here, he doesn't need to fight anymore. The woman who originated the remembrance project is long dead, leaving behind an AI modeled after her as an overseer and recording angel. Angels will become a subtle motif as the story continues. It was the Doctor's refusal to regenerate that caused a disruption in the fabric of Time that interrupted the plan to take the Captain's memory before returning him to his moment of death. Yet this also enables the Doctor to save the lives of the Captain and all the soldiers on that front. Saving lives one last time.
It's fitting to end the story with the Christmas Armistice in World War I. It reinforces the theme of a reprieve from death. The Captain and the soldiers on the front find a moment of peace and respite. In real life, fighting resumed the next day and both sides went back to killing each other. This is a memory the Doctors are witnessing, an event that has already happened. It's another symbolic landscape the Doctor walks in on his journey. That the Captain turns out to be Lethbridge-Stewart, the father of his friend Brigadier Alastair Lethbridge-Stewart – bringing the Doctor's life and actions full-circle. He has been a guardian angel to the captain and his family for the decades to come. It's fitting that the last the captain sees of him is as a half-remembered ghost on the battlefield. The angel who saved his life.
Now the Doctor says goodbye to his friends and emotional ties. He's visited by the ghosts of friends long past in an echo of Dickens. They're also like angels forgiving and absolving him. This enables him to go off alone – to let go of the last part, himself, before he can move on and let the new Doctor arrive.
The TARDIS is Mother. It always takes and leaves the Doctor where he or she needs to be, because Mother always knows. The TARDIS is where the new Doctor is born, and now she's cast out of the womb, tossed back down to Earth, back to Life. Where everything begins again. The new Doctor will make new decisions, new mistakes and new relationships. The cycle of life continues.
Doctor Who will return in 2019 for a New Years Day special.