5. What actually happens when The Doctor changes time?
If he can change it at all, that is. 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!”.
It’s unclear whether the Doctor meant it was disastrous to do so, or if he was confirming the ‘ink is always dry’ paradigm of time travel (no matter how hard you try, you’ll never be able to change history). However, one thing’s for sure: that rule went out the window pretty quickly.
Entire stories have revolved around The Doctor changing time, particular in the aforementioned Genesis of The Daleks, where The Time Lords task The Doctor to wipe their tin-pot foes entirely from history.
But this problem seemed to be resolved with the rebooted series and 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. And if you change one of these fixed points? Reapers, creatures that feed off temporal paradoxes, would appear to restore order.
Well, sometimes… Although Rose Tyler incurred their wrath in series one episode Father’s Day, where were the reapers when River Song refused to shoot The Doctor on the beach in Utah? Were they on annual leave when Amy and Rory created a paradox by jumping off a roof in The Angels Take Manhattan? And why did the Doctor simply suggest in 2013’s Hide that paradoxes simply “resolve themselves”?
Of course, there’s one well-worn semi-explanation that could rationalise it all. Come on, all together now: wibbly-wobbly, timey-wimey.
6. Were the UNIT stories set in the 1970s or 1980s?
Just a warning: this canon inconsistency won’t exactly get your cloister bell ringing. In fact, on the face of it, it seems somewhat pedantic to wonder exactly when The Doctor teamed up with the United Nations Intelligence Taskforce (UNIT). But it’s an issue that’s been addressed by countless web pages, and even its own documentary, The UNIT Dating Conundrum.
And it all boils down, essentially, to one question: when did the Brigadier retire? In Fifth Doctor serial Mawdryn Undead, we learn that the moustachioed UNIT commander retired from the organisation 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. Fans have tried to materialise a solution with theories of alternative universes and multiple Brigadiers, but nothing has been able to dissolve the UNIT controversy.
Yup, instead of concentrating on if The Doctor can change the entire history of the universe, or even why Captain Jack doesn’t react to hearing the name ‘The Face of Boe’ in Utopia (see the 3.20 mark below), the Whoniverse’s main concern is when the Brigadier’s retirement party was. God bless the Whovians.