The 10 best time travel movies ever made, according to a metaphysicist

I am a professor in philosophy and joint director of the interdisciplinary Centre for Time at the University of Sydney. My research focuses on the nature of time and on our relationship with it. I work in the metaphysics of time in philosophy, but my work intersects with both physics and psychology. My next book will look at how our temporal experiences inform our preferences about where in time we want good and bad experiences to be located – for example, whether we should prefer that bad things are located in our past, not our future, and good things in our future, not our past. Below is my list (in reverse order) of some of my favourite time travel films. I’ve tried to include a range of films from different genres that explore different aspects of time travel – but be warned, discussing them properly means there are some spoilers!

10. Midnight in Paris (2011)

Unlike many time travel films, Midnight in Paris isn’t focused on the metaphysics of time travel. It has no interest in exploring how time travel works or what implications it has for how we think about time, free will and the past. It is really a film that explores nostalgia. It follows disillusioned screenwriter Gil Pender, who is visiting Paris with his girlfriend. Every night at midnight, he “catches” an old car that takes him back to 1920s Paris. This is an interesting time travel film because unlike many such films, it isn’t about wanting to change the past. Rather, Gil is caught up in the romance of the past, constantly thinking about how much better life was in 1920s Paris. He comes to realise that wherever we are located in time, we often pine after earlier eras, mistakenly believing them to be the golden age. It is rare that time travel films explore the idea that the past is somewhere we want to go, rather than somewhere we want to change, and that is why this film is on my list.

9. Bill and Ted’s Excellent Adventure (1989)

This is an example of what metaphysicians call a consistent time travel story – one in which time travellers don’t change the past, although they do causally interact with it. In inconsistent stories, the time traveller is depicted as altering the past so that it goes from having once been one way (a way in which there is no traveller present) to later being a different way (a way with the time traveller present). Since philosophers think there is no way to change the past in this manner, they take these stories to depict impossible (and hence inconsistent) things. By comparison, consistent time travel stories are those in which the time traveller has always existed at the past time; the traveller will no doubt causally interact with the past, and in doing so they will make the past be the way it always was.

There is a single scene in this film that alone makes it worth watching. Bill and Ted need keys to get into a building. They don’t have the keys, but they reason that as long as they will, in the future, be able to get access to the keys, they can travel back in time and leave their younger selves the keys. Moreover, they figure that the keys will already be there waiting for them if they succeed, in the future, in travelling back and leaving them. And they are. This is a classic illustration not only of consistent time travel, but of a time travel loop: the keys are where they are because they will put them there, and they will decide to put them there because that is where they now find them.

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8. Back to the Future (1985)

This is a classic time travel film. I include it because it is an example of an inconsistent time travel story, in which, by travelling back to the past, Marty McFly accidentally changes the past and puts his parents’ relationship in peril. As a result, not only is the future that Marty knows imperilled, but his own existence and that of his siblings are jeopardised. After all, if his parents never become a couple, then they will never be born. Faced with his non-existence, Marty has to try to get his parents together to ensure the future of him and his siblings.

This is an example of the so-called grandfather paradox. If someone travels back in time and kills their grandfather before their father is born, then they themselves won’t be born – but, as a result, they won’t be present to kill their grandfather, and as a result they will be born and be able to travel back in time. Most philosophers think that the grandfather paradox can be resolved by noting that no time traveller will ever succeed in killing their grandfather even if they try. Since Marty almost accidentally succeeds in changing the past in a way that undoes his existence, this is an impossible story. But that doesn’t make it any less entertaining.

7. About Time (2013

This is a film about changing the past in myriad small ways. Tim, the protagonist, learns that he can go back in time and do things differently the second, third and fourth time around. This isn’t really a film about the metaphysics of time travel, though if it were, it would depict an impossible story. It is an exploration of what we value and what we would change. Tim discovers that in changing the past to protect his sister, he thereby changes the identity of his future child. He realises that the present is the sum total of all the tiny choices we make along the way; change the past and we change the present. Ruminating on what he values, Tim not only changes the past back to how it was, but learns to value the present for what it is.

6. Everything Everywhere All At Once (2022)

This is an amazing surrealist film. I don’t know if it really counts as a time travel movie; it might be better described as a universe-hopping film in which the body of Evelyn, the protagonist, is periodically taken over by a version of herself from a parallel universe. The film explores the idea of life choices, depicting a world in which every choice-point creates multiple universes in which different choices are made. It is a meditation on the startlingly different lives we might have had, had things only gone a little differently.

5. The Time Traveler’s Wife (2009)

This is a great consistent time travel story. It depicts Henry, who, as an involuntary time traveller, lives his life largely out of order as he bounces around time. He is largely disconnected from others until he meets Clare, who is later to become his wife. The film explores the connection between Clare and Henry, who keep meeting each other at different times in their lives. Sometimes, an older Henry meets a very young Clare; sometimes, a much younger Henry meets an older Clare. The film is a rumination on the ways in which our lives intersect and on what it would be like to lead a life in which events don’t simply unfold from past to future, but instead one jumps around in time.

4. Interstellar (2014)

At last, a science fiction film. The story follows Joseph Cooper as he tries to find a wormhole through which humanity can escape a dying Earth. This film is unusual since it explores travel to the future, rather the past, via time dilation. What makes this particularly interesting is that it is the only film here that is even remotely scientifically plausible. It is the closest we are going to get to an investigation of the only kind of time travel we are ever likely to encounter.

Interstellar explores the effects of a supermassive black hole on a crew who go down to investigate a planet and come up only a couple of hours later, from their perspective, but find that 23 years have passed due to the time dilation caused by the massive gravitational effect of the black hole. Since time passes much more slowly nearer a black hole than it does outside of it, this is a way of travelling to the future (though without hope of return).

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3. Tenet (2020)

This is definitely a film that bears watching a few times. It certainly takes the idea of time travel to a whole new level. Rather than simply having people travel to an earlier time, it incorporates the idea of objects and people who are “inverted” with respect to entropy, and hence are moving backwards in time in the same way that you are I are moving forwards. So, from our perspective, these people look they are doing everything in reverse, while from their perspective we appear to be moving in reverse.

It is a fascinating premise since we know that, in principle at least, these kinds of processes can be reversed. Our laws are time reversal invariant, which means that, for any process that can occur, the reverse process can also occur. In that respect, at least, the film gets the science right (though it remains much less easy to see how a device could invert the entropy of small local regions in the way that it does). This is another film that depicts consistent time travel. At one point, we not only have the protagonist fighting with a time-travelling version of himself, but fighting with an inverted version of himself too. I can see why it took Christopher Nolan some years to write, but it is well worth the watch.

2. 12 Monkeys (1995)

This is one of my favourite time travel films, and a fantastic example of a consistent time travel story. It also depicts a causal loop, which occurs when it is both the case that an earlier event causes a later event, and also that the later event causes the earlier one. In this instance, James Cole is sent back in time from 2035 to 1996 because in 1996 there is a deadly outbreak of a virus. He isn’t sent back to try and prevent the outbreak, since in 2035 they know that the outbreak occurred and that the past can’t be changed. But they want to find the origin of the virus to help develop a cure. Having looked at historical records, Cole believes that an organisation called the Army of the 12 Monkeys, headed by Jeffrey Goines, is responsible for disseminating the virus. As it turns out, the Army of the 12 Monkeys wasn’t the source of the epidemic. But here’s where the causal loop comes in: it turns out that Goines started the organisation because he heard about it from Cole himself. And of course, Cole heard about it because Goines started it. So we have a causal loop.

1. Predestination (2014)

This is my top pick. It is based on a story by Robert Heinlein and is a fantastic example of a consistent time travel story. Predestination is fascinating because although it appears to contain three distinct characters (two men and one woman), in fact there is a single person who is both her own mother and her own father. Jane  (who as it turns out is intersex and has both sets of reproductive organs) meets and falls for a young man and bears his child. When he subsequently vanishes, she is heartbroken and her life runs off the rails. Later, she becomes a man, John, and he travels back in time to meet Jane.

The film explores the idea of free will and predestination. John remembers the events from the perspective of being Jane, but despite how painful those moments were, when he travels back as John, he meets Jane and fathers their child, then abandons her. To complicate matters, it turns out the baby that Jane bears is then transported back in time and left at an orphanage, growing up to be Jane (and then John). Thus, Jane’s very existence is a causal loop. She is both her own mother and her other father: she comes into existence from nothing. The film is a study in the ways in which we do, and don’t, have control over our lives.