The 7 biggest contradictions in Doctor Who canon

Who or what really created the Daleks? Is the Doctor really half-human? And why didn't he always have two hearts?

Day of the Doctor 2013

Doctor Who: the most successful British sci-fi show ever, a beloved adventure across time and space that’s brought incalculable joy to millions. And it makes no sense.


Since Who materialised onto screens in 1963, writers have pulled at the show’s plot threads from all sides, tearing a series of Slitheen-sized continuity holes across its canon. During our time in the Tardis, two different alien groups have destroyed Pompeii, our poor Earth has met its final destruction twice and the Whoniverse’s Atlantis has been destroyed on no less than three separate occasions.

And although stories have seen the Time Lord retroactively fix plot holes by changing history (itself a concept Will Hartnell’s Doctor advised against – more on that below), many contradictions still stand tall.

That’s not necessarily a bad thing – the legion of Whovians offering theories to explain discrepancies prove just how wonderfully dedicated the fandom is. However, for the moment, here are the questions the show itself hasn’t (yet) provided an answer for…

1. Is The Doctor 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 seeming proof 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.

However, some have argued that there’s every chance The Doctor is indeed a mix of the two species after Peter Capaldi’s arc in series nine. The plot centres around a prophecy promising that a “hybrid”, thought to be a crossbreed of two warrior races, is destined to untangle the web of time. And in the same episode, The Doctor announces that the hybrid is “me”.

Could it be that The Doctor was actually referring to Maise William’s character Ashildr, also known as Me? Or is The Doctor really half-Time Lord, half-human after all? Well, not in a way that would make sense of Doctor Donna Noble…

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.

But hey, if we’re willing to forget Sylvester McCoy’s Doctor’s death by random-gang-shootout from the TV Movie, we can sure ignore the whole half-human business.

2. Why hasn’t The Doctor always had 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 auton 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 many fans have taken the incident to mean that the First Doctor only had one heart – yet they offer a simple explanation as to why: Time Lords only grow a second heart after their first regeneration.


It 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.