Steven Moffat explains to BBC America (well, they reprinted the Doctor Who magazine interview) why our numbering system won’t change:
So, ever since “The Name Of The Doctor” ended with the legend “introducingJohn Hurt as the Doctor,” discussion and debate has raged across the internet as to where he may fit in the lineage of Doctors that we currently know about, and whether this effectively means that the current Doctor—Matt Smith— is now the Twelfth Doctor, with Peter Capaldi being his Thirteenth (and supposedly final) incarnation.
Well, according to Steven Moffat, the John Hurt Doctor, who was revealed yesterday to be more warrior than doctor, is an anomaly, and therefore doesn’t count.
“I’ve been really, really quite careful about the numbering of the Doctors,” he told Doctor Who Magazine. “He’s very specific, the John Hurt Doctor, that he doesn’t take the name of the Doctor. He doesn’t call himself that. He’s the same Time Lord, the same being as the Doctors either side of him, but he’s the one who says, ‘I’m not the Doctor.’ So the Eleventh Doctor is still the Eleventh Doctor, the Tenth Doctor is still the Tenth…”
And you remember that comment he made recently about people mis-counting the Doctors so far? He’s explained what he meant by that too:
“Technically, if you really counted it, the David Tennant Doctor is two Doctors, on account of the Meta-Crisis Doctor [grown from the Doctor’s severed hand in “Journey’s End”]… It’s not a matter of counting the regenerations, but of counting the faces of the Time Lord that calls himself the Doctor.”
Got that? To qualify as the Doctor you need a different face AND the name. Which means the Warrior Doctor is exempt from classification.
“There’s an anomaly Doctor slotted in somewhere, that’s all. In the script to “The Day of the Doctor,” Matt’s Doctor was called the Eleventh, and David’s was called the Tenth, so the numbering stays exactly the same – and we call Peter Capaldi the Twelfth Doctor.”