Steven Moffat: Well not that it matters in the slightest what I think, nor is it remotely canonical, but since you ask, here we go…
Missy is winding up Bill, and the Doctor is amused and pleased at the choice of name. Have you seen the many ways he dresses? He is not at home to Mr Subtlety – I think he’d LOVE being called Doctor Who. And because Peter has always wanted to say that’s his name, and I serve at the pleasure of the Time Lord, here we all are.
However, I am firmly of the belief that this real name is unknown, and that he goes by the title Doctor. I also believe that was the original intent of Doctor Who’s creators, and that Doctor Who was never intended as anything other than the title and the premise of the show. It is a question, nothing more. They just left off the question mark, that’s all. I don’t know why. Maybe they ran out of letraset, or an interesting cat walked past. Doesn’t matter, that is what I believe, I hope it’s what you believe, and that is forever that.
Except of course my belief is entirely wrong. And so, probably, is yours.
Look, if we’re going to take continuity seriously (and anyone who even reads this surely must) then his name IS Doctor Who.
Sorry, but yes it is. Put down that chair. It’s an actual canonical fact. He was called Doctor Who on screen, in the proper BBC show. It’s mentioned, twice, in the William Hartnell story The War Machines. The Mighty Hartnell himself performed the script without complaint and no character on screen is surprised by the name or disputes it. Doctor Who – that’s his name.
Later the Patrick Troughton Doctor calls himself Doctor von Wer (German for Doctor Who) and the Jon Pertwee Doctor builds his own car with WHO on the licence plate. These are facts. You can check.
Continuity is continuity. You can’t just ignore the bits you don’t like. (Blimey, my nose just grew six inches!)
So there you go. His name is definitely Doctor Who.
Except I believe it definitely isn’t.
I will continue to believe this, despite the fact that I’m definitely and canonically wrong.
I also believe in all three contradictory versions of Atlantis presented on Doctor Who and the two different fates of the Marie Celeste. I entirely accept both versions of the Loch Monster as the one and only. I believe the Doctor has both one heart and two hearts. I believe he is a human from Earth and a Time Lord from Gallifrey. I believe he built the Tardis himself and also that he stole it from someone else, and that Susan is really his granddaughter, and also that she isn’t.
Above all, I believe that embracing a hundred impossible contradictions elevates Doctor Who from a simple TV show to a myth retold and reinvented by every generation. And since myths can last for ever, let’s all be happy about that.
His name is Doctor Who. You’ve known that since you were a child. Except of course it isn’t. Though secretly. you’ve always known it is.
I hope that clears everything up.
PS. If all this really bothers you, good news. Missy has explained. He briefly flirted with the idea of being called Doctor Who, then abandoned the idea, with occasional slip-ups. Sorted, move along, Atlantis next.