|Time Lord of Gallifrey. Not in 1966 he wasn't.|
Apparently Doctor Who has 50+ years of canon and beware fiddling with the canon. Canon is a word we've borrowed from religion to describe - effectively - the facts that are apparently non-negotiable in the world of Doctor Who.
Of which I'd argue there are precisely...none.
Now the pure 'canon' is, of course, only what we've seen on television. So that would exclude Virgin New Adventures, Big Finish, The DWM Comic Strip and a lot of other Doctor Who apocrypha. Now me, I like to think it is all canon. Even when it makes no sense or utterly disgrees with something we've seen elsewhere.
Because Doctor Who is a time travel series that accepts the existence of multiple universes and alternative timelines. Generally, of course, like in all these things there is a hierarchy of what might be acceptable and what isn't. To me - pretending to be a neutral observer - this hierarchy is based on the degree of seriousness involved in the material plus the format it is presented in. So Big Finish and Virgin New Adventures, BBC Eighth Doctor Books, Missing Adventures et al are easier to swallow as part of a canon that the First Doctor's adventures with John and Gillian in the TV Comic Comic strips.
But mainly what is canon is what we as individuals get hung up on.
So when it was first said that Time Lords could only regenerate 12 times, back in the mists of the 1970s, fans were annoyed. This wasn't something that had ever been established. Or said. In fact you can argue that the 'regeneration' from First to the Second Doctor wasn't even an actual 'regeneration' as it is understood now. We've retrospectively decided that the First Doctor was a Time Lord from Gallifrey with two hearts. Even though none of those things would be 'canon' if you only watched the First Doctor's era.
The Daleks, created as they were for a one off story, were trapped in their city. Unable to move outside, operating on static electricity. They weren't the intergalactic threat they became. They weren't Kaled mutants. They were Dals. There was no Davros. All these things came later and retrospectively we - as fans - have tried to pull all the threads together.
So what am I saying here? Well there is a canon. But it isn't set in stone. Doctor Who's canon is what the last story tells us it was. So 'New' Doctor Who stripped all the baggage away from The Cybermen and popped in on an alt-Universe version with a whole new creation myth.
Could The Moff have ignored the 12 regenerations rule? Yes, he could have done. He could have come up with any number of explanations but he wanted to make a big deal out of it because he wanted to set up that big end of an era feeling, even though he's tied some poor future Doctor Who producer/showrunner to having to go through the whole thing again in 11 regeneration time. By which point of course accepted Doctor Who canon could be completely and utterly different.
As Doctor Who fans - as opposed to the general viewer - we choose what is canon based on personal preference. Me, I think all of it counts. Except the bits I don't. So important was canon once upon a time that the JNT used Ian Levine as an advisor on Doctor Who's past. So successful was that exercise that we got Silurians with third eyes that - for reasons that passeth all understanding - operate to let us know which of them is talking as opposed to being the focus for mental weaponry it was in The Silurians. So that went well.
Terrance Dicks, and I paraphrase here drastically, said that there was no Doctor Who 'bible' just what he could remember of his predecessor's work. And what those that followed remembered of his. Others have pointed out that this stuff shouldn't get in the way of a good story. I'm inclined to agree.
So to cut this short enough for me to get back to my proper job I'd say this. Canon is what I care about. Canon is what I - or you - choose to accept. And we can all go down the pub together and discuss how we can explain the triple destruction of Atlantis or why all those monsters that were busy helping humanity to develop in order to improve their plans weren't tripping over each other (and forgetting about it in the case of the Silence) or how the Skarasen and the Borad manage to co-habit in Loch Ness.* It's more fun that way.
For me it's one of the reasons I love Doctor Who. It doesn't have a set in stone, nothing can ever change approach. Sometimes a writer changes something I liked and makes it something I don't - yes, Mr. Moffat I'm looking at you - but that's my issue to deal with.
Doctor Who never stays the same. That's one of its glories.
*They didn't. I suspect the Skarasen had the Borad for breakfast on about the third day. That's my theory and I'm sticking to it.
PS I almost wanted to call this Canon & Balls but thought better of it.