"I'm the Doctor."
The Doctor started using the name as a form of anonymity, so he could slip in and out of history without leaving a trace, so the authorities couldn’t track him and records wouldn’t remember him.
“The Doctor? Who? Who is he really? We know nothing about him!” Ian made a big deal about that at the beginning, and it was a common refrain among those the Doctor visited (back when stories were longer and scripts didn’t have to save time by handwaving “Why do the locals trust him?” with magic paper.)
But he avoided talking about himself. “I’m a citizen of the universe and a gentleman to boot” was the closest we had for a long time, and that was in a Christmas special. The Third Doctor only had his “When I was a little boy” anecdote about learning to appreciate the world around him. Four came closest to making a big deal about himself with “I’m a Time Lord… I walk in eternity,” while Sarah made faces in the background, teasing him for a brief bout of pomposity. And Five said, “Don’t mention it. Really, don’t mention we were ever here.” He always had that self-deprecating, “I’m the Doctor…how do you do?”
Here’s where my memory gets fuzzy, because high school and my first year of college began to distract me from re-watching the episodes I’d recorded off TV, first on audiocassette and later on VHS, over and over. (Also, sadly, it took me years to get over that Peri-strangling scene, and I don’t think I ever rewatched Colin’s after their first broadcast.) Did the Doctor start making a big deal about “I’m the Doctor!” as Six, or was that only Seven? And how much of that is EU?
There was an oddness in the final season or so – I didn’t know about the Cartmel Masterplan – where the Doctor was starting to act like he was Somebody Special, that “THE Doctor” was a badge of pride and self-identity, whereas before “the Doctor” was a mask, a cover, a John Smith alias to allow him to be a free agent slipping in and out unnoticed.
Because I still find it strange in new Who when he says, “I’m the Doctor; I do X and Y!” I mean, I don’t stand around on the streetcorner saying, “I’m so-and-so, and these are my characteristics!”
More fundamentally: while there was an air of mystery in the old show about the Doctor, primarily Doctor Who was NOT about him. It was more, “Doctor? Doctor who?” In a dismissive sense. The focus of the show was far more about his adventures, the worlds and people he encountered, and what happened there than it was about him or his companions. HIS focus was on being a space tourist, a cosmic hobo, a citizen of the universe, a dropout who wasn’t all that impressive compared to others of his people, and the worst calamity that ever befell him was being stranded for two whole seasons on Earth.
I’m wondering when the shift happened. When “the Doctor” went from being a way of deflecting questions about who he was to a proud self-identity which he and those around him defined on a regular basis, aloud, in declarative statements.
I feel like there was a touch of that with Seven, when Cartmell started to redefine the character as someone special, but still, it wasn’t a big part of the show.
Nowadays, “Who is the Doctor?” seems to me to be a central question to some stories, and even when it isn’t, he and his companions seem preoccupied with it. I feel like that’s the biggest shift between classic and new Who.
And yes, I know I’ve nattered about this before, but I just saw several “I’m the Doctor…I am X and Y” photosets from new Who cross my dash along with several classic Who photosets making pithy comments about predicaments and plans: character vs. plot, to boil them down to essentials.