Is Doctor Who changing the rules of time travel?

Let me explain. During the episode it’s revealed that the dead, “orphan” planet our heroes are trapped on is actually a far-future Earth, implied to have been made largely uninhabitable by nuclear conflict and global warming and left a husk of its former self.

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Obviously, this was a bit of a downer for regular Earth-dwellers Yaz, Graham and Ryan (Mandip Gill, Bradley Walsh and Tosin Cole), but in the episode’s closing moments the Doctor suggested there was still hope.

“I know what you’re thinking – but it’s one possible future. It’s one timeline,” the Time Lord tells her friends.

“Unless people face facts and change, catastrophe is coming. But it’s not decided. You know that. The future is not fixed, it depends on billions of decisions and actions, and people stepping up.

“Humans. I think you forget how powerful you are. Lives change worlds. People can save planets, or wreck them. That’s the choice. Be the best of humanity,” she concludes.

In of itself this seems like a fairly unquestionable message – look after our planet better and maybe this future won’t come to pass – but it is a slightly different presentation of time travel than Doctor Who has usually presented.

Yes, as the Doctor has said many times before, time can be rewritten – but there needs to be somebody holding the pen. Excluding fixed points in time and so on, Doctor Who usually presents changes to history and/or time as something enacted by an outsider from that particular timestream, be that a traveller in the TARDIS, an alien threat or some other unusual incursion.

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By contrast, in this episode the Doctor seems to be suggesting that humanity might pull together and undo this turn of events by themselves – but they already haven’t! Unless something changes, the fact that the Doctor and co went to Orphan 55 means that it has happened. It’s not a possible future, it’s the current status quo. Stuff doesn’t just fix itself!

If time really was shifting in this way, surely every time the Doctor and her team went to a new planet or time period it’d be completely different? Maybe Rosa Parks would have had tentacles! Ada Lovelace might have been more into the clarinet than Maths! And the next time the gang return to Sheffield? Whoops, nuclear winter happened in the 1980s now, everyone’s dead. Don’t worry, though, they might be alive again next time we visit.

I’m being slightly facile here, of course, but unless the Doctor is suggesting that Ryan, Yaz and Graham personally go back home and change things, just the three of them, relying on humanity to magically avert a future that’s already set doesn’t make sense based on the sort of storytelling the series has engaged with in the past.

Look – obviously time travel isn’t real, and the sort of story you tell with it is always based on previous depictions in pop culture rather than any real scientific evidence. I once interviewed the co-creator of time-travel drama Timeless, Shawn Ryan, who noted that no-one ever complained when he changed the real-life procedures of police officers in cop dramas to make the story more interesting, while tweaks in the format of time travel tend to be torn apart online.

“I like to joke that for a science that doesn’t actually exist at the moment, people are very adamant about what they believe the rules of time travel to be,” Ryan told me.

But even if the rules of time travel are made up, they do need to be a little consistent – and for a series like Doctor Who, which bases its whole format on a certain depiction of this idea, it feels like the structure the series has built over the last few decades has been a little undermined.

Of course, it’s unlikely this will be a regular change to the way Doctor Who depicts time travel, and more than anything it serves a purpose here of reminding the audience at home about their own responsibility to and ability to change the future of the environment and the planet. In real life, we can’t always depend on the intervention of an immortal saviour with a blue box – it’s up to us to make the future we want.

But if Doctor Who flipflops on its own storytelling conventions every time it wants to make a dramatic point, the impact of said moments can only diminish – and that’s not a good time for anybody.

Doctor Who continues on BBC One on Sundays