Why so serious? Tenet and the new wave of 'science-based' time travel movies

Back in the good old days, time travel in the movies was a strictly no-strings-attached affair, a straightforward plot device to bewilder a couple of high-school dimwits or dispatch a killer robot on its mission. It was used to spice up action films, adventure films, even romcoms – the only rule was that it shouldn’t be thought about too hard. The biggest conundrum it might cause was how to fend off the advances of your own unsettlingly attractive mum.

What John David Washington’s secret agent in Tenet wouldn’t give for such trivial problems. He not only needs to save the world from a supervillain armed with nuclear warheads and a time machine, but also get his head around the news that his nemesis can invert an object’s temporal properties at will, thus sending it hurtling backwards through a space-time continuum that is not as linear as he thought. Worse still, so do we.

Moviegoers could be forgiven for feeling a certain sense of deja vu: Christopher Nolan’s film is part of a growing trend for blockbuster plotlines that unpick time-travel and all its implications in head-spinning detail. Nolan could even be argued to have started the fad: since Interstellar (for which his co-writer and brother Jonathan studied relativity at the California Institute of Technology) we’ve had Synchronicity, Time Trap, In the Shadow of the Moon and the forthcoming Volition – all of which demand serious mental gymnastics in order to keep up with the plot. Things reached their peak last year when the biggest grossing film of all time, Avengers: Endgame, had its heroes cite – and dismiss – a raft of classic sci-fi capers while plotting out their elaborate masterplan. “If you travel back into your own past,” explained one, “that destination becomes your future, and your former present becomes the past, which can’t now be changed by your new future.” Bill and Ted, it ain’t.

Then there was Denis Villeneuve’s Arrival, a film whose key plot point, much like Tenet’s, hinged on a conception of time alien to the human brain. All very clever – except it’s humans watching the film. Arrival avoided becoming an indecipherable mess because of its gripping story, big-hearted characters and the odd line of plausible dialogue. The same can’t be said for Tenet, which gets so caught up in the microdetail that it forgets completely the first rule of popcorn cinema: we’re here to have fun. As Spinal Tap’s frontman said: “It’s such a fine line between stupid and clever.”

Not that every film which takes time-travel seriously is quite so joyless. In the Shadow of the Moon told its knotty plot with a freewheeling charm. As did Predestination, with the added benefit of having Ethan Hawke guide us through it. Looper softened its pseudo-science with a rollicking hard-boiled detective story. But they all devoted serious thought to time-travel’s maze-like logistics, and insisted that we did too. The plot device has come a long way since the days when Marty McFly and the TX-100 zipped back to change the future without any worry about its repercussions. The logical problem of the premise – that the time-traveller, if they were to succeed, would never exist in the first place – was of similarly little concern to audiences, whose ticket receipts ensured sequel upon illogical sequel. As recently as 2004, a film that truly waded into the cause-and-effect conundrum was consigned to the ultra-niche fringes: the ingenious Primer, which has since gained a sizeable cult following, made less than $1m in ticket sales.

No doubt Primer was ahead of its time. These days it is compulsory to acknowledge the conundrum, maybe even try to solve it. Tenet gives it a name – the Grandfather Paradox – and dedicates a number of scenes to our hero mulling it over with Robert Pattinson (conclusion: “There is no answer – it’s a paradox”). The recent TV series Devs went one further, using a story about quantum-particle engineers to delve earnestly into the free will v determinism debate. Again, it felt more like homework than home entertainment. More successful is the Netflix series Dark, which has the most absurdly convoluted story of the lot, taking place over two parallel worlds, each with five different timelines. Staying on top of it all is a nigh-on impossible task made bearable by the show’s devotion to its lively array of characters and its frequent deep-focus shots of luscious German hillscapes. Existential reasoning is central to the plot. Nietzsche quotes feature prominently.

Perhaps the real trend here is nothing to do with time-travel at all, but the way philosophy has suddenly found itself at the forefront of pop culture. Debates that were once limited to textbooks and lecture halls are now the basis for crowdpleasing TV. The Good Place contains chirpy discussions about Kantian ethics, Westworld’s characters are forever fretting over the nature of consciousness, Rick and Morty is about the meaning of life. In Hollywood, ideas that used to be the preserve of Spike Jonze and Darren Aronofsky are being discussed on screen by the Hulk and Ant-Man. Steven Spielberg ventured into virtual reality with Ready Player One. And with Prometheus and Alien: Covenant, Ridley Scott has returned to the cerebral sci-fi that made his name.

Are blockbuster movies getting smarter? Or, in an age where TV gets all the intellectual kudos, are they simply making more effort to appear smart? Either way, the lesson from Tenet is that the truly clever decision is often to keep things simple. Certainly most people who spent £15 and three hours to see it would like the option of travelling back into the recent past, no strings attached.