In his newest book, author James Gleick explores the history of Time Travel. And its future. A conversation about fascination, regret, and killing Hitler.
Early on in your book, you write that time travel isn’t possible. That it can’t be. Did you go into this research wondering if it was?
No. The honest truth is that I thought from the beginning on that it was just a fantasy. And I know very well that there’s something perverse about expecting people to read a book about time travel by someone who doesn’t believe in it. I worried about that at first. And I’ve discovered, as I’ve been talking about the book, that many people are disappointed that that’s my opinion. I have to reassure them that to honestly represent the view of mainstream physicists, I have to say that they don’t want to rule it out. They like to believe in time travel. If you’d like to imagine that some day we’ll have a time machine and go to any year that we want, you’re free to do that. It’s just not something I believe in.
I wasn’t expecting the revelation that traveling through time would be possible, but I didn’t expect your sober reasoning either: “You can’t go into the past. Because you didn’t.” Is it really that logical?
No, it’s not. There is something complicated about my approach to the question. When I talk about philosophers making that sort of argument, I find myself making fun of it.
”You can’t logically prove time travel”
Why is that?
A lot of philosophers have said “time travel isn’t possible” and proved it logically. My view is different from that. I don’t think you can logically prove it. It’s a matter of having a consistent view of how the universe works. The logical arguments are kind of silly and have become word games – like the one you mentioned. But I actually end up giving a lot of thought to what time is, which is what the books turns out to be.
You also talk a lot about how language is insufficient in describing time – the sentence I quoted seems convincing but doesn’t necessarily reflect the physical reality.
That’s true. But also: The way physics works is not the be all and end all. It’s not an absolute representation of reality. Physics makes models of things and uses them to predict real-life events. That works very well. Yet it’s very different from making an absolute statement of what is and what isn’t real. So to put my view into a simple way: If you believe that the present is real, and that the past is not real because it’s already done, and the future is not real because it hasn’t happened yet, then you have what I’d call a normal sense of time.
This is what people think before they start to worry too much about the details. The past is gone, we don’t have access to it. The future hasn’t happened, and maybe we have some degree of free will and can make choices about the future. I can have cheese for lunch or I can have ham. Until I do one or the other, that future is not yet determined. That’s a common sense view of things and lots of philosophers have considered that that’s not how things really are. And more recently, so have lots of physicists. They have created mathematical models in which it’s possible to view the universe as a four-dimensional space-time continuum. A complete package. In this mathematical picture, the future and the past are every bit as real as the present. They look exactly the same in the equations of physics. But in my view that doesn’t mean we have to accept the mathematical view as a statement of reality – and I think many physicists would agree with me.
”Time isn’t like space”
Because of the impression of free choice? You certainly don’t feel like it’s been predetermined for your to have the ham for lunch.
Right. We don’t have to settle the question of free will, maybe my choice between cheese and ham isn’t as big as I think I do, but at least it feels as though it hasn’t happened yet. The whole notion of time travel implies that this common-sense view of time isn’t right. That you can go back into the past and even change it. You can go into the future and walk around there as if it exists now.
When H.G. Wells invented the first time machine, he realized when he was constructing what he knew to be just a fantastic story, that he was saying something that was different from our common sense view of time. He was saying that time is a fourth dimension, that time is like space. So when we talk about time travel, we are saying that time is analogous to space, that it is a thing you can travel through. And when you stop and think about it, come back to earth, that’s not what I believe. I don’t think is like space, I think it is quite different from space and we all know that quite well, deep in our bones.
It’s funny you’d use that expression, because you also wrote “time travel is in our bones” and that time travel “is a sexy idea”- Is that why we embrace it, despite of its shortcomings?
Let’s talk about the good news – we’ve been focusing on the bad news that there’s no such thing as time travel in a literal, mechanical thing.
”We are imagining new future all the time.”
Of course there is such a a thing as time travel and we’ve all become very expert and efficient time travelers. My book is not meant to just debunk this idea that’s so much fun but rather to celebrate the idea and to appreciate how powerful it has been in our thinking for more than a century. We have a relationship with the past and the future that is very exciting and very rich – even if it’s largely a matter of imagination. That’s ok, because imagination is who we are. We’re imaginative creatures. We have knowledge of the past and a kind of foreknowledge of the future – whether is it based on anticipation or terror. We are imagining new futures all the time.
Is that fascination with the past, for instance, due to our regretful nature or rather our aspiration towards perfection – going back to fix what went wrong?
Both of those come into play. People who create time travel stories, for books, TV, or just in their own minds, are motivated by different things, and you have just mentioned a very important one: Regret. You think about something and you want a do-over. We can all think of great time travel stories that are based on the idea of wanting to do something over and over again. Remember the great Bill Murray movie Groundhog Day: That’s not just a version of the story where he doesn’t want to do it again but finds himself trapped and gradually realizes that he has to live this one horrible day over and over again, until he finally does it right. It’s a variation on the theme.
”Killing Hitler has become a meme”
What does the it mean, then, that our society is so enamored with time travel.
It means we think a lot about history and about how things might have been different. It’s not an accident that one of the great memes of time travel of the late 20th century is “What if the time traveler would go back to kill Hitler in a timely fashion?” Nowadays – at least over here – you hear people wondering if it might be possible to go back and teach manners to Baby Trump. Can we change history? Is the world we’re living in the only possible world? Or might it have been different. Is it just an accident that everybody is driving around in automobiles with internal combustion engines or, if one little thing had happened in the early nineteen hundreds, would we all be driving around in electric cars instead? To pick just one trivial technological example…
In the book you reveal the role technology plays in our thinking about time travel: The idea of the time machine is directly linked to industrialization. But at the same time, it seems that there’s more to it: We’ve come to accept that machines can solve so many problems that thinking they would break the laws of time doesn’t seem too far off…
Of course we have a love-hate relationship with our machinery. I have always been interested in connections between technology and the rest of our culture. The way we live and think about the world is often unconsciously a consequence of devices and machines that are part of our life. That’s true about my last book, The Information, which was all about advances in information technology. And it’s certainly true with how we deal with time. It’s not just that H.G. Wells invented time travel at a time when there were railroads and steam engines and electric telegraphy synchronizing clocks around the world; it was also when Einstein reevaluated physics and reshaped scientists’ sense of time. And that’s not a coincidence. Our cultural understanding of how time works was being reshaped by the availability of clocks, high-speed transportation, new kinds of light speed global transfer of information.
”A paradox in many guises”
A development that has continued.
Now it’s all happening again. And this is where I found an ending for my story. It looks as though our sense of time is undergoing a new revolution. Where that’ll lead isn’t quite clear but we can already tell that in our highly-networked world, where so much of our experience comes to us through screens of different sizes and shapes, our relationship with the present, the future and the past is changing again, in tricky ways.
You mean: There’s time-shifting going on across the culture?
Right. We’re expert time-shifters. We’re watching TV with instant replays, tape-delayed version of an instant replay. We’ve gotten very smart about this and I think that occasionally we can forgive ourselves if we suffer a little bit of confusion as well.
Speaking of confusion: What is your favorite paradox that you encountered during your research?
In a funny way, it’s all one paradox that keeps turning up in different guises. There’s one – that I won’t try to explain: the central kind of loop in the movie La Jetée by Chris Marker, which not many people know, but which some people have seen the remake of, 12 Monkeys.
A lighter version of the paradox appears in Woody Allen’s Midnight in Paris. His time traveler goes back to the 1920s and meets Louis Buñuel, the film director. He says “I have a great idea for a movie for you” and pitches him his own movie. And the young Buñuel says “That doesn’t make any sense!” It’s a paradox: If Buñuel did make the movie based on what the time traveler had told him, the question becomes: Where did the idea come from in the first place?