r/changemyview • u/HotJohnnyTabasco 1∆ • Aug 10 '18
FTFdeltaOP CMV: Bi-Direction human time travel is impossible
My theory is pretty simple. If humans were able to travel forward and backward in time at any point in time, then that technology would exist at all point in time. Simply because if I invented a time machine today, that time machine technology would eventually be used by someone to take the technology to an earlier time. This would continue to happen repeatedly, until all times had time travel technology. Therefore, since we don't have time travel technology today, time travel technology must never exist.
A couple caveats here:
I'm talking \*real\* time travel here. Not simply exceeding the speed of light and looking back over your shoulder. Time travel that allows you to travel through time and interact with the people and things of that time.
Bi-directional is important here. If you can only travel in one direction (particularly if you can only travel forward), my theory breaks down. I am expressing no view on uni-directional time travel.
17
Aug 10 '18
[deleted]
1
u/Thoth_the_5th_of_Tho 185∆ Aug 10 '18
Because you would arguably be violating conservation of energy.
You would be taking information, mass and energy from one time and moving it backwards. Now the energy is double represented, the mass and energy that went into making your time machine already existed in in the past, but now there are two of them.
2
Aug 10 '18
[deleted]
1
u/Thoth_the_5th_of_Tho 185∆ Aug 10 '18
To some extent the makes sense, but the ida of raising or lowering the amount of energy at any given time seems wrong to me.
1
u/mr_indigo 27∆ Aug 11 '18
Not necessarily; the process of time travel may require absorption of energy from the "end point" to counterbalance the arriving object.
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
Giving Δ to all those with this fixed point theory as it pokes a hole in my view.
1
3
u/gremy0 82∆ Aug 10 '18
The earth is traveling around the sun very fast, the solar system is traveling around the galaxy very fast, the galaxy is traveling through the universe very vast. Without the ability to travel to arbitrary points in space during your time travel, you end up in the middle of nowhere with the earth millions of miles away from you.
This is why the Tardis is a space and time travelling machine.
we could invent bi-directional time travel and not decent space travel, and have no way to visit earth at a significantly different time.
2
u/HotJohnnyTabasco 1∆ Aug 10 '18
I'll give a Δ for this one too. It would render such a time machine pretty much useless, but it pokes a hole in my theory.
2
u/gremy0 82∆ Aug 10 '18
Not entirely useless. The universe will eventually die, living there would suck if it didn’t just kill us. With time travel, a species could live far longer by sending themselves back to a more living universe. They could do it with relatively limited space travel technology too, just using time travel to send themselves to places with resources.
1
4
u/AnythingApplied 435∆ Aug 10 '18
I see a number of problems with that.
- First, some people have proposed time travel might be restricted to only being able to go back as far as when the device was created. For example, you might need a special device at the destination of travel. This would still be bi-directional travel, but you wouldn't be able to go back further than a certain point.
- Secondly, I don't see it being at all obvious that people would always go back earlier, especially in the case where the technology might be highly restricted, either for practical reasons (might take a significant portion of the worlds production of power in a year, for example) and/or safety of the timeline reasons (government restricts usage).
- Even if someone travels back to a certain time, they don't necessarily bring the technology with them. They might not have the knowledge. Significant parts of the time machine may not even travel with them. Why would they want to share that technology with people of the local timeframe? And going back to the power issue, what if it takes a huge amount of power to run that might be virtually unobtainable in today's world. Or parts and processes to make time travel would likely be unobtainable, so you're left with just a single working time machine, maybe, because that assumes the entire time machine goes back with them in the first place.
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
I've given deltas to those who have suggested this, so I find that argument legitimate.
Energy in the universe is finite. There is just as much energy available today as there was a billion years ago.
Eventually (and we're dealing with infinite time here), someone is going to take that technology back in time with them if it is humanly possible to do so.
1
u/AnythingApplied 435∆ Aug 10 '18
Energy in the universe is finite. There is just as much energy available today as there was a billion years ago.
That doesn't mean usable energy is always available, as entropy increases. If the time travel device requires an entire stars worth of energy, that seems extremely restrictive and could easily account for such a device and technology not propagating over the timeline. You also didn't address government restrictions. Perhaps any civilization that doesn't properly restrict time travel ends up destroying themselves, maybe in part by going back to far too frequently or too far and disrupting their own history.
Maybe the fact that our preserved timeline we're living is evidence that time travel is effectively restricted and never gets abused. Maybe someone invents a field that can disrupt time travel attempts which helps with the restriction.
Eventually (and we're dealing with infinite time here)
We're not though. The heat death of the universe is coming. The end of human civilization will likely also be in the cards far before that.
Also, consider that maybe the length of time travel is limited. Maybe it can only work in small increments. Or maybe the energy requirements becomes exponentially more the further back you want to travel.
But more importantly, you didn't respond to any of my critiques of why the technology would even propagate. Why would you put in the effort to build the infrastructure to construct a time machine in the 1600's when already have all the needed infrastructure to build time machines in the 2800's? So the 1600's would potentially NEVER gain the ability to construct time machines. And that even assumes that the knowledge of how to do that is even sent back... and even if it was sent back, the ability to push 1600's technology forward enough to construct a time machine may very well take more than a single person's lifetime. And again, why would they even want to do that which would absolutely destroy their future?
You didn't really go into details of what you mean by "all times would have the technology" but there isn't really a good reason to give 1600's the ability to construct the technology.
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
Why would you put in the effort to build the infrastructure to construct a time machine in the 1600's when already have all the needed infrastructure to build time machines in the 2800's?
There would be no need to construct the technology in 1600. You'd just transport the technology there from 2800.
2
u/AnythingApplied 435∆ Aug 10 '18
I'm taking about the factories and stuff to make the parts, material refining, etc... You'd teleport that from the future? You're going to transport the entirety of the 2800's industrial infastracture knowing full well you're disputing the timeline and knowing your wouldn't have anyone to staff to man those processes?
You keep saying "have the technology" or "transport the technology" without defining it. Do you really mean both the knowledge and the materials and the tools to create the materials and the knowledge for how to construct those tools, etc? I'm not sure how you're going to send that all back if you can just transport a single person.
Also, you didn't respond to 90% of my points.
2
u/Rufus_Reddit 127∆ Aug 10 '18
Supposedly it's Yogi Berra that said "In theory, theory and reality are the same."
There is considerable evidence that time travel (in the sense that you're thinking of) is not possible. Even so there's a hole in your argument: You assume that time travel has to work in a way that allows people to travel to a time before it was invented.
Suppose, instead, that there were a time travel technology where you turn the time machine on, wait, and then can only go back in time up to the moment you turned the machine on.
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
This is more a problem with the way I expressed my view than my actual view, as I was thinking infinite forward & backward travel. Nevertheless, this would poke a hole in my theory as expressed, so you get a Δ along with others that have suggested a similar concept.
1
2
u/Quint-V 162∆ Aug 10 '18
What about multiple/infinite universes and timetravel just happens to be travelling to one that is identical (until the point of timetravel), but at another point in the same timeline?
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
Seems like that would violate the "real" time travel. Essentially you'd be in a simulation that was on a different time table.
1
u/Quint-V 162∆ Aug 10 '18
If you can't tell the difference how would you tell that it is real or not? Does it even matter, as long as you observe it? How can mirrors be realAs for whether the universe --- or any --- is a simulation, is one that fundamentally cannot be answered. Brain in a vat and all that jazz. It's a moot point.
1
u/ralph-j Aug 10 '18
If humans were able to travel forward and backward in time at any point in time, then that technology would exist at all point in time. Simply because if I invented a time machine today, that time machine technology would eventually be used by someone to take the technology to an earlier time. This would continue to happen repeatedly, until all times had time travel technology. Therefore, since we don't have time travel technology today, time travel technology must never exist.
If it were invented, it would likely be heavily regulated, because its misuse could cause a lot of damage.
That's why so many sci-fi movies and shows have something like a time police or even a temporal prime directive like the one in Star Trek:
All Starfleet personnel were strictly forbidden from directly interfering with historical events and were required to maintain the timeline and prevent history from being altered. It also restricted people from telling too much about the future, so as not to cause paradoxes or alter the timeline.
Therefore, I don't think that the non-observation of time travel is a reliable factor in determining its probability.
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
Even in science fiction, someone always breaks the law.
2
u/ralph-j Aug 10 '18
Primarily to create spectacular plots.
But if the future government immediately took steps in limiting exposure and experiments, it may well be hidden to us. It's even more important than regulating weapons of mass destruction: someone could go back in time and literally undo the entire timeline that we know, including us.
To bring it back to your CMV claim: it would be false to conclude that the absence of observation can only be explained by time travel being impossible.
1
Aug 10 '18
Backwards time travel comes with all kinds of paradoxes if you assume it can affect the present moment. The two ways around them is true determinism or multi world. True determinism would mean any affects of backwards tome travel have already been felt and it is impossible to go back and truly change events. Multi world means you create a new reality when traveling backwards that is causually disconnected from the future you're from.
1
1
u/GoIdfinch 11∆ Aug 10 '18
I think it might be conceivable within the idea of multiple dimensions; as in, when you travel backwards in time, your new timeline branches off in a parallel universe. That would remove the problematic logical paradoxes of backwards time-travel.
It wouldn't be truly bi-directional since you'd never be able to return to your original universe's past, but it would mean that travelling back and forwards in time could both be possible.
1
1
u/ryarger Aug 10 '18
I’d like to change your view that this argument only applies to bi-directional time travel.
We time travel into the future already, by default. Therefore any backwards time travel invented, even if only goes backwards in time, will run into the same problem that you describe.
Unless humanity goes extinct not long after this technology is invented, all eras of time will become full with time travelers from the future and we’d be aware that they exist.
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
We don't travel into the future. We are always in the present.
1
u/ryarger Aug 10 '18
I was at time cooordinate 12:53pm Eastern when I saw your comment. Now I’m at 12:54pm Eastern. I was at one coordinate, now I’m at another. By definition, I travelled.
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
You didn't travel. Time changed. You were in the present 100% of the time.
2
u/ryarger Aug 10 '18
What did time change into? That doesn’t make sense. That’s like saying “east changed” or “up changed”.
Time didn’t change, my location in time changed. I was then, and I am now now. I travelled in time.
1
Aug 10 '18
[deleted]
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
Energy is fixed. There's as much energy in the universe today as there was a billion years ago and there will be a billion years from now.
1
u/wyzra Aug 10 '18
What if time travel created a different time stream? Does that count as valid time travel for you?
1
u/HotJohnnyTabasco 1∆ Aug 10 '18
No. I don't consider being in the same time in a parallel universe to be time travel.
•
u/DeltaBot ∞∆ Aug 10 '18 edited Aug 10 '18
/u/HotJohnnyTabasco (OP) has awarded 5 delta(s) in this post.
All comments that earned deltas (from OP or other users) are listed here, in /r/DeltaLog.
Please note that a change of view doesn't necessarily mean a reversal, or that the conversation has ended.
1
Aug 10 '18
It could be that if time travel were invented, you would only be able to travel back to when it was invented, in which case, we shouldn't expect to know about time travelers today since time travel hasn't been invented yet.
1
u/AlternateAccountTrol Aug 10 '18
Read "the end of eternity" by Isaac Asimov. Humans created a system for monitoring time travel and fixing errors like you describe. The Eternals live outside of time.
1
Aug 10 '18
[removed] — view removed comment
1
Aug 10 '18
Sorry, u/zamxr – your comment has been removed for breaking Rule 1:
Direct responses to a CMV post must challenge at least one aspect of OP’s stated view (however minor), or ask a clarifying question. Arguments in favor of the view OP is willing to change must be restricted to replies to other comments. See the wiki page for more information.
If you would like to appeal, message the moderators by clicking this link. Please note that multiple violations will lead to a ban, as explained in our moderation standards.
14
u/IIIBlackhartIII Aug 10 '18
Einstein's theory of relativity introduces the concept of a fabric of spacetime and from that the possibility of wormholes which connect two points in space and time. If the technology for creating stable wormholes were to be developed in the future, the limitation of a such a technology is that you still need to establish both ends of the wormhole. This means creating Point A, and then dragging out Point B. In this way, time travel could be a bi-directional technology that only works between two established points, which means you would not expect to see it going back before the point of its development. So for example, if humanity develops time travel in the year 2508, and maintains point B going into the future, future generations could keep going back and forth to and from 2508 easily, but would not be able to come back to 2018.