Every major fandom has a list of things that are canon, a body of established facts and events that later writers and producers can draw from. To do something that contradicts or ignores canon is the biggest crime a new writer can commit. Unlike other universes like the Star Trek and Star Wars universes, the BBC has never made a pronouncement about what is or is not canon for Doctor Who. Shortly after he brought Doctor Who back to television in 2005, Russell T Davies specified that canon "is a word which has never been used in the production office, not once, not ever". Similarly, at a 2008 San Diego Comic-Con panel, Steven Moffat remarked, "It is impossible for a show about a dimension-hopping time traveler to have a canon.” But as far as many fans are concerned, Doctor Who definitely does have a canon, and it’s routinely rewritten. Here are eight times Doctor Who ignored its own canon.
8. The TARDIS’s Power
While it’s natural for a show to evolve and grow, so the TARDIS has grown and become more powerful over the seasons. However, there have been several inconsistencies in terms of what it is actually capable of. We are told in several instances that, when fully active, the TARDIS's outer defenses are impenetrable, but then later told that the Daleks, being TARDIS experts after the time war, can get through with no problem. That said, there are multiple scenes in the modern era of Daleks being unable to breach the TARDIS shields.
Similarly, the TARDIS is supposed to translate written and verbal language on the fly, with one instance where this doesn’t happen explained away by the language being “impossibly old”. On several other occasions, where is was done for dramatic purposes, the language translation simply didn’t occur or was delayed. Where it was delayed until after the TARDIS left, it was explained as “sometimes it takes a while to kick in”, which doesn’t actually explain the situation.
7. Two Hearts
Apart from his powers of regeneration and trusty sonic screwdriver, The Doctor’s dual heartbeats have been the main method employed to distinguish himself from humans. But he hasn’t always been sporting two pumps. Although the Third Doctor’s 1970 adventure 'Spearhead from Space' established The Doctor has two hearts, previous stories have a different take on this core of Gallifreyan biology. The prime exhibit: William Hartnell story 'The Edge Of Destruction' (1964). In this early story – the show’s third ever – The Doctor falls unconscious thanks to a faulty TARDIS and companion Ian comes to his aid. But while examining the Time Lord’s chest, Ian notes “his heart seems alright”, making no note of a second heartbeat. The Doctor’s assistant may simply have not have noticed two tickers, but it’s unlikely. It also doesn’t quite explain how Hartnell’s character was able to function without serious discomfort (David Tennant’s Time Lord found himself in extreme pain with only one working heart), but until the new Doctor provides a second opinion, it’s the best diagnosis we have.
6. Half Human
Most Whovians agree that although Paul McGann’s Eighth Doctor definitely happened, almost all the events of the infamous 1996 Doctor Who TV movie didn’t. And that’s mainly because it claims that The Doctor is half-human - twice! Not only does The Doctor himself declare he is half-human “on my mother’s side”, but The Master also confirms the claim later with a retina eye scanner. And whether that was down to the TARDIS’s chameleon circuits working overtime, or simply a writing room decision to make The Doctor more relatable, it didn’t go down well with fans this side of the pond. In fact, over 20 years on, they’re still mourning the canon change on Youtube. During her last episode, Catherine Tate’s character is made half-human/half-Time Lord by a genetic meta-crisis, courtesy of the Z-Neutrino Biological Inversion Catalyser (obviously). And this transformation is made possible by mixing the Doctor’s DNA with Donna’s, meaning The Doctor must be full Time Lord – if not, Donna would be only a quarter Time Lord.
If a fan theory is the only explanation we get to solve a question, there is a problem. It’s hard to measure the age of a time-traveling alien, and it seems The Doctor has a hard time keeping track as well. That said, there is no consistent life-span of a regeneration. While it’s clear that the First Doctor died of old age, we don’t know how old he was. The Second Doctor at one point says he’s “something like” 450 years old. But then the Eleventh Doctor spans at least 500 years before starting to look old. The fan theory is that time only affects a Time-Lord if he stays in time for a long period, but that is shaky at best
4. When Did The Brigadier Retire?
When did the Brigadier retire? In Fifth Doctor serial 'Mawdryn Undead, we learn that the UNIT commander retired from the organization in 1976. But in 'The Invasion' – the first story in which UNIT properly appear – it’s established that the organisation was founded in 1979. So how could The Brigadier have retired from an organisation that didn’t exist? And there are further inconsistencies: in 'Pyramids of Mars', Sarah Jane states she’s from “1980” and that before time-travelling she came into contact with a non-retired Brigadier. This suggests he was working at UNIT in 1980, which creates another contradiction.
3. Rewriting History
The First Doctor completely rejected the idea of meddling with the past, firmly stating in 1964’s 'The Aztecs' that “you can’t rewrite history! Not one line!” Whether he meant ‘can’t’ or ‘shouldn’t’, that rule went out the window almost immediately. Entire stories have revolved around The Doctor changing time, particular in the aforementioned 'Genesis of The Dalek's, where The Time Lords task The Doctor with wiping their tin-pot foes entirely from history. This problem seemed to be resolved in the modern era with the introduction of the ‘fixed points in time’ concept. It sounded simple: although certain events had to follow through unchanged, everything else could be altered without too many consequences. If changes were made, then Reapers, creatures that feed off temporal paradoxes, would appear to restore order - except when they don’t. Several other major time points are completely changed by The Doctor and his companions only to be met with no resistance.
2. The Daleks
Davros created the Daleks, right? The alien race of Kaleds in their war machines, right? This memorable origin story was told in the classic series’ 'Genesis of the Daleks', in which Tom Baker’s Doctor is tasked with preventing the Daleks from ever being created. However, this story ignores a lot of previous canon. When they first appeared in the second ever Doctor Who story, the Daleks were described as evolving from Dals, not Kaleds. And instead of having a creator, The Doctor describes the Dals as a peaceful race who were poisoned by a harrowing neutronic war, thus forced to live life inside a robot shell. Granted, this serial established that the Dals came from Skaro – the same planet Davros is based on in Genesis – but the two stories simply don’t match.
1. 12 Regenerations?
For younger fans only accustomed to the revived series, there’s already some confusion about how many doctors exist. That’s thanks to A) the War Doctor – effectively now the eighth reincarnation of The Doctor – introduced to the show for its 50th anniversary special, and B) the episode where David Tennant’s Doctor regenerates into himself. So when Jodie Whittaker was unveiled as the “13th Doctor”, she was actually the show’s 15th incarnation – albeit the 13th actor to take on the role. But the regeneration issue gets thornier if you consider Tom Baker-era tale 'The Brain of Morbius'. In that serial, the Fourth Doctor engages Morbius in a potentially deadly mind-bending contest, with some strange results. The fight causes several faces to appear on a screen behind the two: that of Tom Baker, followed by Jon Pertwee, then Patrick Troughton, William Hartnell and, very oddly, eight others, seemingly in period dress. Was this battle supposed to reveal the previous incarnations of The Doctor before Hartnell? That was certainly the intention of Philip Hinchcliffe, producer at the time. “I just reasoned that it was entirely possible that William Hartnell may not have been the First Doctor Who. So yes, as far as [we] were concerned, the other faces were meant to be past Doctors… it is true to say that I attempted to imply that William Hartnell was not the First Doctor.”