So. Age range. Most Doctors began in their early-to-mid forties: Troughton, both Bakers, McCoy, Eccleston.

Two began in their early-to-mid fifties: Hartnell and Pertwee. (Hartnell sure seems a lot older, doesn’t he.)

Davison and McGann were in their thirties; early and late, respectively. Tennant turns thirty-four in two days.

In order:

55->44->51->41->31->41->44->37->41->34

There’s a certain regularity here, although the trend has been toward younger Doctors. Davison was the watershed; where before forty-one was a “young” Doctor, now it was comparably old. And that’s the pattern we’ve had since.

It’s a little odd how often the actors are exactly forty-one, or something-one. It’s either that or something-four, the only exceptions being Hartnell and McGann.

So it’s true that Tennant is the second-youngest Doctor; the transition is a lot like the one from Tom Baker to Davison or McCoy to McGann, except that both Baker and McCoy had aged by the trade-off and were then closer to the range of Hartnell or Pertwee. So the trade-off was to an appreciably younger man, much as it has usually been. There’s a certain significance to that concept: age trading itself in for youth. Now, we’re going from a Doctor who is still pretty young to a Doctor who is even younger. That’s a first. And that’s probably where the noise is coming from.

If Tennant sticks around for seven years — as long as Tom Baker, and as long as anyone’s held onto the role — he’ll only be as old as Eccleston is now. This means we’re not going to see a “mature”, paternal Doctor any time soon. At least, not unless McCoy comes back for a visit. Although Davison’s Doctor was younger, he had a short life before regenerating into older men. Although McGann was around the same age, he only ever appeared the once. In contrast, the idea here is that Tennant is supposed to persist for a whilie. He’s the Doctor we’ve really been waiting for; Eccleston was just setup.*

I guess this brings up the question of why he diidn’t just bring back McGann for the first season, if that was his plan all along. The only answer I have there is that McGann’s been done. He wanted a new start with the audience; a Doctor without a history to him, that we could get to know from the start. Rose is the audience; if we already know the Doctor, we’re too far ahead of her. He wanted the audience to feel ownership over this Doctor — like he was new out of the wrapping instead of a hand-me-down. Then when Davies kills him off, it will have more weight.

I guess it also brings up the question of why Davies didn’t choose an older Ninth Doctor, to provide contrast. I assume it’s because he wanted this Doctor to be new, and it makes little sense to regenerate into a geezer. The only time the Doctor has regenerated into a substantially older man was in the case of Pertwee, and that was imposed on the character by the Time Lords. So it seems like there aren’t too many options here; to get the effect Davies seems after, you need a youngish man for the Ninth Doctor, and you need an even younger man for the Tenth.

How, then, does this clash with public expectations? It’s because we’re used to the idea of a paternal Doctor — even if the only one we’ve had since Pertwee is McCoy. We have this image in our minds of an elderly chap. After all, he’s been alive for so long! That’s a little odd when you think that we also most associate Tom Baker with the role — a weird-o beatnick cross between Harpo Marx and Dracula. Maybe it makes some sense if you consider how short-lived the following four Doctors were, and how many problems the show had through the ’80s. We tend to forget about everyone after Tom Baker, leaving us with some kind of a cross between Baker and Pertwee and some idle memory of Hartnell and Troughton. And where does Tennant fit into that!

Well, he doesn’t. What he does fit into is the established mythology and overall pattern of the series. The trend has always been toward a younger Doctor; now we’ve got another. And furthermore, the mythology is still growing. The pattern is no longer static. The show is alive again, and Davies has his own ideas. So really, everything is about as well as it might be.