I’m a big fan of the current Doctor Who. Matt Smith is up there with David Tennant and Tom Baker as the most engaging of all Doctors, and under Steven Moffat the show has extended its sense of excitement and playfulness. But there is a big problem looming for Moffat and co.: they are writing too many time travel paradox stories and if they are not careful, the paradoxes will end up eating their story arcs.

Time travel stories generally divide into two forms: those in which the time travel is a narrative device to put the characters in different settings, and those in which the time travel is itself the point of the story. The first sort of story, the time-tourism story, is primarily interested in exploring; a good example is the Irwin Allen television series The Time Tunnel, in which a broken time machine hurls its characters into new settings every episode. One week they’re on the Titanic, next they’re on the first manned (yes, this was the 1960s) mission to Mars. Time travel here is just a mechanism to shuttle characters around in history — and this version can be very cheap to film as the series can draw on sets and costumes stored for other series. A famous literary example is Mark Twain’s A Connecticut Yankee in King Arthur’s Court, in which the method of time travel is a blow to the head (clearly not intended as a scientifically plausible time machine!), and Twain’s purpose was to satirise contemporary nostalgia for the Middle Ages.

The second type of story, where the mechanics of time travel matter, generally focuses on question of destiny, the moral questions of changing the past, and other philosophical intrigues. “A Sound of Thunder” (the short story, not the godawful movie) and 12 Monkeys are great examples.

Both types of stories can be mixed into the same narrative, as in Back the the Future, a time travel paradox story and a scathing look at 1950s values.

Once upon a time, Doctor Who was very firmly in the time-tourism camp. The Doctor and his TARDIS would jump about through time and space and have an adventure at each location. In the very first series, the Doctor and his companion Barbara appear in Mexico just a few years before the conquistadors are due to arrive, and Barbara is mistaken for the reincarnation of an ancient high priest. As she admires the many achievements of the Aztecs, uses her position to convert the Aztecs from their culture of human sacrifice, reasoning that their culture might survive the conquistadors if human sacrifice is abandoned. Ultimately she persuades only one person, a priest who exiles himself from Mexico, and meanwhile the Aztecs continue their sacrifices and it is implied the Spanish conquest will proceed as before. The Doctor tells Barbara, “You can’t rewrite history. Not one line.”

The Doctor nailed his colours to the mast way back in 1964, but it was never going to last. Regardless of the philosophical and scientific arguments about the immutability of history, from a writer’s point of view it is just too damned tempting. We want to play with history. And Doctor Who, as a series, has never shown much concern for continuity anyway.

Over the years, Doctor Who serials slowly began to introduce elements of the second sort of time travel story, where the way time works is important to the plot. The second series ends with a story called, bluntly enough, The Time Meddler. The Doctor travels back to Viking-era England and discovers a monk with a wristwatch who turns out to be planning to wreck the Viking fleet in order to prevent the Saxons losing the Battle of Hastings.

Slowly the time-meddling became a larger part of the Doctor Who narratives. We saw Doctors meet past versions of themselves (a scenario so successful that it was used several times, the script usually being written to reflect the number of past Doctor Who actors alive at the time), time-trapped aliens as Egyptian gods (decades before Stargate), and increasing causality concerns. At the same time, the stakes became ever higher. From stories about the Doctor dealing with small groups of people, he began to save whole cities, then civilisations, then planets. This escalation has brought us to the point where the Doctor must now save the universe at least three times per season. (Who knew the universe was so fragile?)

There is nothing wrong per se with the time-mechanics story, and one of the best ideas in the independent Doctor Who novels was Faction Paradox, a clan of time-travelling gangster-cultists who create paradoxes and causal absurdities just for the sheer hell of it (created by Lawrence Miles). But time-mechanics stories need to be handled carefully. It is extremely easy to paint oneself into a corner and then solve it with time travel. This can give a vicarious thrill at the time, but it is the science fiction equivalent of the old Western trope of the cavalry riding over the hill. If you can go back in time and undo anything, then nothing matters. If a character dies, they can be saved. If a disaster happens, it can be averted. A perfectly capable time machine is the enemy of suspense.

In recent Doctor Who stories, the best (or worst) case is The Girl in the Fireplace, a beautifully written story about the Doctor meeting the real Madame Pompadour, intertwined with a plot from the far future to capture her for reasons far too complex to describe here. The Doctor, as it turns out, harbours a fixation for Madame Pompadour, and meeting her only amplifies his old obsession. Madame Pompadour, for her part, comes to care deeply for the strange man who keeps appearing out of nowhere to save her from terrifying abduction attempts throughout her life. The story ends sadly when the Doctor promises to take her to see the stars, but materialises too late. Madame Pompadour has died and he has broken the promise he made to her. This was a stunning episode, and the script was extraordinary (it was one of Moffat’s solo efforts before taking over the series), but it suffers from the fact that the premise of Doctor Who is that the Doctor has a time machine that can take him anywhere in time and space. The TARDIS is not perfect and it often dumps him in awkward situations, but surely for Madame Pompadour, fire of the Doctor’s passion and exemplar of his obsessive love for the human species, he could have bloody well tried to land the TARDIS somewhere along her timeline.

The Girl in the Fireplace manages to work anyway, largely because of the brilliant script (I believe I may have already mentioned it already), but also because it was a single, standalone episode.

The other problem with time-mechanics stories is that they tend to become snagged as plot lines and causality get all twisted up together. Sometimes this knot of causality can be a deliberate component of the story (see the movie Primer), but for a TV show that is attempting to stretch a causality-twisting story arc across 2 series and 26 episodes, I am worried that the knot will become too thick and tangled to make for satisfying story-telling.

I’m willing to give Moffat the benefit of the doubt for now, and because he has already mapped out this series, but I do think that Moffat is going to have to take a different tack in the next series if he wants to avoid the story being sucked down its own plughole.

Tags: doctor who, time travel, time-mechanics, time-tourism