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⏰ The Ethics of Time Travel ⏰

Even if we could, doesn't mean we should

I love the idea that Einstein’s Relativity tells us that, by traveling really fast, we can travel forwards in time. After being on the International Space Station for six months, astronauts come back a few milliseconds into the future. Nobody notices it, but we can measure it. If we can do that, could we ever really go back in time? No? You sure about that? It’s fun to think we could, though, right?

The Appeal of Time Travel

Time travel. It’s the darling of science fiction, the ultimate undo button, and the number one way to deliver you from unpleasant consequences. Whether it’s Marty McFly kissing his teenage mum or the Terminator turning up naked, we love stories that break the one rule of physics we thought was immutable: time can only move forward.

What would you do if you could go back in time? Like Phil, would you want to save the girl you have your heart set on? Or would you want to see the launch of Apollo 11? Go to a Shakespeare play at the original Globe Theatre? Try to prevent 9/11? Get a ticket to ride on Concorde? Undo what caused your break-up? Get there in time to tell your dad you loved him one more time?

But, for all the fun we can have with paradoxes and time anomalies, there’s a bigger question we might be asking: Even if we could time travel, should we time travel? If we change something in the past, can we really be in control of all the ripples? The consequent future unpleasant consequences?

The answer is complicated. And it’s not just because of ripples through time and the butterfly effect.

The Baby Hitler Conundrum

Let’s get it out of the way: Baby Hitler. The quintessential time travel morality test.

So, you go back in time. You’re holding an infant Adolf. Do you kill him to prevent all that suffering?

Let’s assume we can go back in time, but that we still can’t see into the new future from that moment. The ethics get fuzzy very quickly, because messing with time assumes an enormous amount of being right that what comes after the change will be better for everyone. The further back in the past, the further the ripples will spread out from the moment that is changed. Do you have that much self-belief?

It’s an interesting dilemma, mostly because it assumes you’re both cold enough to kill a baby (though you could always assassinate him as an adult) and it supposes that you’re confident enough in your history to know that this will definitely prevent World War II and the holocaust.

The real issue stops being about killing an infant for the greater good. Maybe it’s really about being able to truly predict the outcome.

What if Hitler was a symptom, not the cause of the disease. Maybe worse things happen when he's removed from the equation (history rarely leaves a vacuum unfilled). Maybe the Nazis win WWII under the leadership of a better war strategist. Or maybe someone even more evil and more determined to ethnically cleanse. How would it feel to realize you made that happen when you get home to your own timeline?

Do Time Travelers Cheat at Life?

One of the less debated moral questions about time travel is how unfair it would be. Like Marty McFly and Gray’s Sports Almanac, you could go back and win the lottery, or buy bitcoin and Apple shares, using future knowledge. You could pass every exam, take every opportunity, undo every mistake, and give your past self the chance to play a mulligan… but isn’t that a little bit cheaty?

Time travel would allow you to play the game of life with the cheat codes on. What if morality requires a degree of struggle, or earned success, then aren’t time travelers ethically compromised? Like the athlete who finishes the London marathon having ridden the Tube and still expects a medal.

Free Will vs. Fate

Now, I don’t believe that anything is predetermined. Like the Rush track, I prefer Freewill as a universal paradigm. I don’t really believe in fate. I kinda wish I did, because it might make me feel better about how I got where I am. But as it is, I got here through some tough times and a whole bunch of brave/foolish decisions. And since I wouldn’t want to change where I am now, surely I wouldn’t go messing with my past.

But what if some other smart-arse with a home-made time machine decided to change their life and messed up mine in the process? But then, that would just become my new reality and I wouldn’t know any different, right?

On the other hand, if your future is predetermined—if time is fixed, and already written, rather than an ever-branching path—then you were always going to go back in time. You were always going to date your grandmother and become your own grandfather. For you to be you, genetically, you would already have to have gone back in time to be your own grandfather, even before you were born. Before you travelled back in time. You see? It’s full of paradoxical nonsense!

The Grandfather Paradox

Let’s say you do time travel. You follow all the rules. You don’t touch anything, you don’t kill anyone, and you don’t invent the internet 50 years too soon (good job). And you don’t date grandma. But then you accidentally prevent your grandfather from meeting your grandmother. Oh, whoops! You’ve just created a paradox. And not just any old paradox, a (chrono)-logical one; the kind that makes philosophers weep, and physicists sigh heavily. If they don’t meet, you won’t be born. So how could you have gone back in time to stop them from meeting? Sigh.

The Past Is Not A Playground

Let’s talk about time tourism. Imagine wealthy people from the 25th century visiting the 21st just to gawk at our quaint, little ‘smart’ phones, our cars that can’t hover, our Social Media addictions, and our gluten intolerance. Time travel opens up the possibility for time tourism and temporal exploitation.

You think people are obnoxious now? Wait until they’re demanding oat-milk lattes in the Renaissance and turning up in Rome in 1633 insisting that “Galileo is the GOAT!” The ethics of dropping into the past, consuming its culture and then leaving it changed and exploited aren’t a good look for any era. Just because Shakespeare lived 400 years ago doesn’t mean he should be our next vacation destination.

The Cathedral of Chalesm

In Hitchhiker’s Guide to the Galaxy, the Cathedral of Chalesm is a fun thought experiment. One of Douglas Adams’s intriguing threads to pull on when it comes to messing with time. “The cathedral was scheduled for demolition in order to build a new ion factory. However, due to delays in construction and a strict deadline for the start of ion production, the beginning of the project was extended so far back in time that the cathedral ended up never having been built in the first place. As a result, picture postcards of the cathedral suddenly became immensely valuable. And blank.” Adams was an utter genius. He died aged 49, and is greatly missed. His Dirk Gently books have certainly inspired me; they are among my very favourite books. Should I go back to 2001 to tell him he had an undiagnosed heart condition? I wish he had written so much more.

Bringing Modern Ideas to the Past

Let’s not even get into bringing modern technology back to "help" ancient civilizations. Even ideas could be dangerous. Sure, you could tell Aristotle that he was right about reality being the tiniest sliver of time between the past that doesn’t exist anymore, and the future that hasn’t happened yet. You could describe to him the concept of Planck time being the smallest unit of quantum time that makes any sense, and perhaps that is the reality of which he had conceived. But could he deal with that? Would the insight into the quantum realm blow his mind completely and send him mad? It blows my mind, and I grew up, at least from the age of 10, with the idea of quantum mechanics. And how would it go if we changed philosophy into science that far back in history?

Personal Gain and Undoing Regret

What if you could go back and undo one thing—the worst decision you ever made? That night. That job. That haircut. Tempting, right? But is it ethical to do that? Regret is part of the human condition. Our mistakes shape who we are (sometimes literally, in the case of that “No Regerts” tattoo). If you could erase your failures, are you erasing parts of yourself? More importantly: what happens to everyone else who was affected by that choice? Your personal redemption might ripple into someone else’s tragedy. Why is undoing your mistake worth more than their happiness? What if your ex gets to un-date you?

Also, if you're constantly fixing your past, are you ever really living your present? There must be a reason we don't get an undo option in the drop-down menu of life. It forces us to try to be better the first time round. How would it be if we knew we could just go back and try again? How would it be if everyone could do that? There would have to be an infinite number of universes to contain that kind of chaos! We would be caught in a world where events were just like the shifting grains of sand as the tide comes in, constantly washing up and rearranging against a tide of everyone else’s whimsy. And that’s why Sci Fi time travel always seems to be limited to just a single time machine, or the one person who can do it. Even then, getting the time travel logic right is difficult enough. It’s too easy to create a paradox.

So, Should We Time Travel?

Here’s the thing: if time travel can create paradoxes, then ethics might be irrelevant. Because if cause and effect can be broken, nothing means anything much anymore.

This is the fundamental problem with temporal morality: if the chain of events is fragile enough to collapse under the beat of a single butterfly wing, then every action becomes both impossibly significant and utterly meaningless. And that’s just too much to even contemplate.

Time travel is appealing because it promises control over the uncontrollable. But life’s value isn’t in its predictability. It’s surely in living now instead of trying to rewrite then. Let’s be honest: humanity can’t even predict the disastrous impact of Social Media and handle that responsibly. Could we really trust ourselves with the space-time continuum?

Maybe the best ethical stance is just don’t. Not because it’s too dangerous to time travel (though it most probably is), but because it undermines the messy, unpredictable, and flawed way that we live our lives.

So, if someone hands you a time machine, here’s the most ethical thing you can do: say thank you, take a selfie, and then throw it into the volcanic heart of Mount Doom. If there’s one thing more dangerous than tampering with time, it’s assuming you’re wise enough to predict the outcome.

But Where Does That Leave Sci Fi?

All of that adds up to make time travel the perfect means to create nerdy, ethically-challenged plot lines that necessitate temporal chaos in some really great science fiction. From The Time Machine to 12 Monkeys, or from Back to the Future to Dirk Gently’s Holistic Detective Agency, time travel is a compelling source of plot twists.