Year 2077 C.E. someone invented a one way time travel into the past safely, the problem is that anyone can replicate the method with ease due to the proliferation of All-In-1 Advanced 3D printers and the weak anti-piracy law. Since it is impossible to stop anyone from going into the past can we at least stop people from developing god complex and drastically alter the course of history in their favours?

This time machine only permits 1 person per usage, destination and exact date of arrival will be randomly chosen for you (any moment between 1 to 9999 years into the past). Luggage must not exceed 1% of your mass and no devices allowed as they can emit electromagnetic waves that cause interference to the time machine.

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    $\begingroup$ Generally speaking, its really hard to get people to think the way you want them to. That being said, what are the rules of time travel for you? Any answer will surely need to know that. $\endgroup$
    – Cort Ammon
    Commented Dec 30, 2016 at 3:50
  • $\begingroup$ @CortAmmon: updated. $\endgroup$
    – user6760
    Commented Dec 30, 2016 at 4:07
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    $\begingroup$ What time travel system are you using? There's literally dozens, and each one has different effects. For example, if you use causal consistency, which is the only time travel supported by physics, you can't change anythign you didn't already change. Or you can have a Primer style time travel where the first time travel box is the most powerful. Or you can have a 12 Monkeys style where time sort of washes over you. You could do a Butterfly Effect, and have some physical key to the process. Time doesn't fly like an arrow. It's more like a ball of wibbly wobbly timey wimey stuff. $\endgroup$
    – Cort Ammon
    Commented Dec 30, 2016 at 4:11
  • $\begingroup$ @CortAmmon: mine is simply cheating the de broglie or matter wave to tunnel the entire subject into the past with absolute precision but lose the accuracy... $\endgroup$
    – user6760
    Commented Dec 30, 2016 at 4:18
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    $\begingroup$ With those restrictions, I have to ask... what sane person would willingly use such a device? It sounds to me a lot like a really convoluted suicide booth... or a fun, futuristic twist on capital punishment. $\endgroup$ Commented Dec 30, 2016 at 18:23

10 Answers 10


This won't be a problem. For simplicity sake, just imagine that you are the time traveler. Got it? Great! So you're a modern human. You're now back in the past. Let's say in the rural wilderness of France of the 1100's. Here we go.

First let's speak the language...oh - sorry. No one actually speaks French. It's some horrible mixture of Latin-Germanic-and Celtic. So, communications is right out.

Let's hunt. You know how to make a weapon right? No, of course, you don't.

Bake bread - easy! Except you need to actually make the flour, harvest the yeast, build a suitable oven...forget bread.

Point is, we won't need to worry about a God complex because modern humans will not survive long in the past. We lack virtually all the skills needed just to get by.

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    $\begingroup$ stonemakerargument.com/2.html $\endgroup$
    – Cort Ammon
    Commented Dec 30, 2016 at 4:37
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    $\begingroup$ Don't forget diseases: Old ones can kill the traveller, new ones the party he joins. $\endgroup$
    – Ayutac
    Commented Dec 30, 2016 at 13:20

Why bother? The time travellers can only carry one percent of their body mass. After the clothes they stand up that leaves hardly anything. No gadgets to subdue empires! A complete lack of skills to cope with past conditions and a lack of the languages to deal with people in the past.

The time machine will arrive randomly somewhere between one year and nine thousand nine hundred and ninety-nine years in the past. Ho hum! These guys aren't a threat to history, they're a threat to themselves.

Consider our god syndrome time traveller landing nine years in the past, apart from babbling about what he might inaccurately remember about 2007 (this is written in 2016). Far from conquering 2007, how we remember Our Glorious leader from the Far Future of Nine Years hence those nine years ago, but if only it happened that way, instead our time traveller is likely to slammed into a detention centre and milked for his scrappy knowledge of the future. Trump for US President, indeed! A obvious lunatic.

Nine thousand years in the past, what's the point of wanting to be a god if you can barely communicate with your palaeolithic ancestors and more especially if you find yourselves totally dependent on them for your food and survival.

No-one is going to bother about preventing God complexes in stupid time travellers who are only going to their death in a past which they are ill-equipped to handle on a conventional, day-to-day level, let alone a history-changing one. The problem is more one of duty of care to mentally bewildered who will only kill themselves with time travel.

Of all the many forms of time travel this is one that is singularly useless for any possibility of changing the past and manipulating history.


Negate Their Existence

Perhaps make sure your time machine only makes use of principles where if you alter the past even a tiny bit, you immediately alter the future enough so that you are never born and cease to exist immediately.

Ideally, somehow the time travel mechanics would be built so that the traveler is somehow exactly linked to the time travel process in such as way that any time travel happens only in a timeline where only they will be effected in the future, and they will be effected negatively--they will never be born, but the rest of the future is unchanged.

Travel Only to Other Timelines

Make sure that any time travelers cannot travel to a timeline that is ours. If they travel back, they get their own unique instance of time that does not effect the future for the rest of humanity, and so it's not such a big deal if they become godlike or severely alter the course of history, since only they will be effected by any changes.

Time Travel Police

Perhaps a police force tasked with tracking down unauthorized travel into the past, i.e. Terminators.

Public Education

Educate the public about any dangers of effecting the future.

Sabatoge the Time Travel Machine Schematics

Aggressively hunt down all existing records of correct time travel machine blueprints and destroy them. Substitute them with copies with errors that involve principles only the anti-time machine bureau understands.

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    $\begingroup$ Download the schematics, build the machine. Press the button. Lights flicker, the machine whirs. Silence. The air is electric. Rick Ashley's "Never Gonna Give You Up" starts playing. The pirate's location is also sent to the time-cops. $\endgroup$
    – Lu22
    Commented Dec 30, 2016 at 7:13
  • $\begingroup$ "if you alter the past even a tiny bit, you [...] cease to exist immediately." The presence in the past alone is altering the past, cause your body temperature will interact with your surroundings. That said, from a certain viewpoint, the "time machine" in this case is just a machine that gives people a short image of the past before killing them. Neat :D $\endgroup$
    – Ayutac
    Commented Dec 30, 2016 at 13:16

Other answers have correctly revealed that travelers from the present will be poorly prepared for their journey most of the time. With 10000 possible years to arrive in, and with an entire planet of geography available within each of those years, only a small percentage of those who take the leap will land on survivable soil. Statistically, most will drown in deep ocean, far from the sight of land.

But that doesn't mean that history is out of danger. The human race produces an almost un-exhaustable supply of ambitious idiots. No matter how stacked the odds are against any one of them surviving the trip, eventually one will land somewhere, where their foreknowledge will be dangerous.

And by dangerous, I'm not talking god-complex level meddling; I'm talking extinction level stupidity.

The fact that we are even here to discuss this problem is just luck. Somewhere out there, someone has printed or will soon print up the time travel machine which will send them back to their personal historic sweet-spot. And once that print-job is finished, so are we.

So set off the EMP devices! Erase the Internet! Cancel the 20th and 21st centuries! The knowledge of time travel must be forgotten before it's too la...


How do you keep them from developing a God complex? Make time travel lethal. Nothing says, "You are not all powerful" as potently as death. Every trip exposes you to radiation. One trip, two trips, per year? Fine. More? Problems start to develop.

Also, the trip arrival point may seem random to users, but something in your physics is rolling those dice... maybe the time machine always drops them at a point where they can't make any difference no matter what they do.

PS: the range of the time machine being 9999 years... that's too coincidental a number. Consider making it a value computed from some universal physics constants that dictate a time horizon.


Single Time Line Theory

The time travel theory I prescribe too, this is the best for your story. There is only one time line. Simple enough. Any changes made to the past are already felt, which means if you alter the past it turns out that is the way it was all along. Time travel can still be seen as negative (altering the past is bad) but no one will notice if you do. How can you develop a God complex if you can't change the past?

Look to the future! It's all you have control of!


It's a one-way trip, to a random time and location. The chances of this turning out good are very low.

  • 70% of the Earth's surface is water. Therefore, 7/10 times they would most likely drown.
  • 33% of Earth's land is a desert. Of the 3/10 times the traveler didn't pop out over water, 1/3 would be in a desert.
  • 50% of Earth is said to be wilderness. I assume this includes desert, so 1.5 times out of 10, the traveler would be deposited somewhere 'safe'
  • If the arrival doesn't kill them, the likelihood the traveler can find food, shelter, and clothing in time to avoid dying is low
  • Even then, the chance that people they ran into would not just kill them outright is pretty low.

So, I need to ask, why would people go back?


They don't know when they are going, therefore they wind up in plague-infested Europe, Rome or prehistory. If they knew when and where they were going, they could bring back facts which would profit them greatly, but since they don't, they have no motivation.


Unless they manage to get mentioned in a history book somewhere, nobody would know what they did. They can't take much tech with them, so acting like a God to primitive people won't work.


The truly desperate may wish to go somewhere where nobody can find them. Think of escaping the Mob or a hostile government. This level of desperation is close to suicide.

If it's one-way, nobody would ever know the machine did anything other than destroyed the traveler. I don't think anyone would use the machine for a one-way trip.


Parallel Timelines

An other option would be that at the point of traveling back in time, the traveler essentially creates a parallel timeline. Any actions in that timeline would change the history of that new timeline, but not of the original. The effects would be only in the new parallel univers, and your history remains untouched.

Statistical improbability

Chances of survival are slim.

  • With having a random location assigned, it is highly probable that you will end up in the ocean, considering 70% of earth is covered with it.
  • And even if you arrive on actual land, most of it will be wilderness(how much depends on the time-period), lets assume an average of 40%.
  • Then there are time-periods where it will be very hard to survive due to war and the brutal living conditions in comparison to today. Not to mentions all the diseases that will kill most visitors. Again lets assume some number for the chance of survival: 50% (kind of optimistic).

The resulting chance of surviving the time jump and the living conditions afterwards is only 0.3*0.6*0.5 = 0.09. So only about 10% that would survive the trip.

For an individual to change history there will also be a certain amount of intelligence required. Lets say 1 in 10 would be able to change anything major. That leaves you at a mere 1% that are dangerous. At this point you could just say it so unlikely that it just doesn't happen.

Changing the past is not possible

In the movie "The Time Machine (2002 film)" after the death of the main character's wife, in an effort to save her, he build a time machine. After going back and saving her, she died again of a different cause. After multiply attempts he then came to the conclusion that the past cannot be altered. You can implement something similar. Let them attempt to change history, but every time they try it it will have no effect or make things even worse.


Breaking news!

We just found another person who accidentally traveled to Pompeii and immediately died in lava. That sounds painful! (Editor's note: probably too quick to be painful.)

We just found another thousand people who died of starvation in the wilderness!

We just found another thousand dead bodies in the desert!

We just found another person who was burned as a witch in Salem!

We just found another person who was eaten by the Donner party!

We just found another person who was eaten in Jamestown!

We just found another ten people who were eaten by cannibals in Africa or Asia or the Pacific islands!

Ooh, we found someone eaten by cannibals in Europe!

Oops, someone got sacrificed to the gods by the Aztecs!

A few thousand travelers just got killed by popping into war zones!

I wonder when we'll find someone with a successful traveling experience?

Make a movie

I'm thinking something along these lines (possibly inspired by Roots). "I am a time traveler." Sound of a whip hitting flesh. "I am a time traveler!" Sound of a whip hitting flesh. Sobbing, "I am a slave."

Time travel survivor

Take people and leave them in random locations. Film them and see how long it takes for them to quit. Rules say that if the person calls a friend, that's the same as quitting. This will help people realize how difficult it is to survive a time travel jump.

Low chances

Given a random place and time, you are far more likely to die than achieve success. You have perhaps a four in five chance of drowning or dying of dehydration immediately, and a one in ten chance of starving in the wilderness. The remaining one time in ten, you only have to worry about suddenly appearing in some country where you don't speak the language. Possibly because no one spoke modern English (or whatever) more than a thousand years ago.

Most of the last 10,000 years weren't that great, and the typical modern person doesn't have skills that would transfer. Perhaps the most useful talent would be killing people, but a single skilled killer who doesn't speak the local language is likely to be killed by some group.

It is possible to succeed, but most people won't. It's hard to prepare for the general problem, as the randomness leaves too many alternatives. It's easy to encounter a circumstance that turns a survivable location deadly. Most people will need help from other people to survive, but not knowing the language and not having anything to trade mean that it's hard to get help.


Did you say "one way"?

As in, they can't ever come back "home" to the present?

And they can't specify where they go, or when?

The only people signing up for this voluntarily will be the suicidal and the desperate!

It might be something you could force on criminals, except that sending a criminal back in time just one or two years might be a blessing, rather than a punishment, especially if they have time to memorise some lottery numbers or share movements ...


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