READ BULLETIN 1147, PEOPLE!
September 8, 2013 10:26 AM   Subscribe

 
Wow. I just watched Looper last night and was extremely annoyed at its incoherent take on time travel. This post is a nice antidote to that. A bit of warning, once you understand the logic behind the fact that you can't kill Hitler, most time travel shows - like Looper - will become unwatchable. If you watch them anyway, you will likely annoy everyone around you by explaining that the plot is logically impossible. You will then want to go back in time and prevent yourself from understanding how it is impossible to change the past, and then you will be sad when you remember you can't.
posted by vorpal bunny at 10:42 AM on September 8, 2013 [4 favorites]


I'm confused -- the io9 article is simply a collection of short summaries of various TV episodes/stories in which characters have gone back in time and tried to kill Hitler, and failed (or succeeded but then Someone Even Worse takes his place), but it doesn't even attempt to explain its own thesis statement. So, I'll ask all of you -- stipulating to the concept of achievable time travel, why the hell can't you travel back in time and kill Hitler?
posted by tzikeh at 10:54 AM on September 8, 2013


Mostly because if you could, then you already have.
posted by Dr Dracator at 10:56 AM on September 8, 2013 [15 favorites]


"You'll Be Thwarted By Other Time Travelers"

I remember reading an issue of (I think) Weird War Tales where an earnest, dedicated young man travels back in time to shoot Hitler. He lines up Hitler's head in the scope of his rifle, completely unaware that his action has already brought about an even worse timeline, and right behind him there is now another earnest young man who risked it all to travel back in time to shoot him! And behind that guy is an earnest young woman, and behind her there's a robot, and on and on... Basically, the rafters at Nuremberg were more crowded than the audience, filled with time travelers getting ready to shoot each other.
posted by Kevin Street at 10:56 AM on September 8, 2013 [3 favorites]


why the hell can't you travel back in time and kill Hitler?

Any kind of time-travel universe change is dependent upon the idea of multiple timelines/universes. There is not, and it's probably impossible to, ever prove such a thing. Whether or not you can go back and kill Hitler is basically a religious belief.
posted by curious nu at 10:59 AM on September 8, 2013 [2 favorites]


A version of this post was originally published on November 20th, 2008.

So, on the positive side, I've proven you can go back in time and post to io9.
posted by Horace Rumpole at 11:03 AM on September 8, 2013 [4 favorites]


> Whether or not you can go back and kill Hitler is basically a religious belief.

Sorry, no.

It's a very rational belief based on the fact that no one has any idea of how time travel would possibly work, but more, that it seems to break all sorts of fundamental laws - forget about the law of cause and effect (and the multiverse paradigm seems to fix that), it breaks pretty well every conservation law (matter and energy, momentum, angular momentum) as your mass (momentum, etc) vanish from the present and appear in the past (where they are doubled).

My belief that I won't win the lottery is not "religious" - it has to do with the laws of chance, and of cause and effect (because I don't buy tickets). And I think the chances of traveling in time are a lot less than winning the lottery...
posted by lupus_yonderboy at 11:07 AM on September 8, 2013 [4 favorites]


What if you went back in time and made Hitler a friend with benefits?
posted by Brandon Blatcher at 11:07 AM on September 8, 2013 [3 favorites]


The basic problem with why you can't do this is the Grandfather Paradox. (They even mention it in the article as the "Hitler paradox.") Basically, if you go back in time and blow away Adolph, then there's no reason for you to go back in time to kill Hitler. ('Cause he's a minor historical figure who died before he could ever cause any trouble.) So when did it happen?
posted by Kevin Street at 11:08 AM on September 8, 2013 [1 favorite]


There was a great episode of the Sarah Silverman show where she stops the Holocaust from taking place via time travel so that she can discredit her sister's Holocaust memorial (after all, it didn't really happen in the altered timeline, right?") and win a prize.
posted by Renoroc at 11:12 AM on September 8, 2013


What if you went back in time and made Hitler a friend with benefits?

That is a very specific fetish....
posted by GenjiandProust at 11:12 AM on September 8, 2013 [6 favorites]


If you traveled back to 1907 and killed young Adolph, wouldn't that merely create a tangential timeline, a la Back to the Future, in which Hitler never rises to power and maybe WWII does not occur? The Holocaust and WWII as we know them would still happen in the timeline that we occupy.

Yeah, you could surmise that we will never be able to travel back in time and change events because if our future selves or societies could do this, we'd already have encountered the travelers or the results of their meddling. But that doesn't account for alternate timelines/multiverses or even concepts that lie well beyond our contemporary ken.

Having spent a great deal of time watching all the time-travel flicks I could get my hands on, I know that every auteur has his own ideas of the complexities of temporal dislocation. Its mind-bending to think about this stuff, but what does real, hard science have to say? And do we even have enough brainpower to think these ideas through, or will we ever? Or are these temporal puzzles too complex for 21st century humans to even contemplate?
posted by Alonzo T. Calm at 11:12 AM on September 8, 2013 [1 favorite]




The Time Machine? Ah, that. I use it to go back to Yosemite Valley just after the Glaciers melted. Only on weekends, though.
posted by mule98J at 11:18 AM on September 8, 2013 [2 favorites]


My belief that I won't win the lottery is not "religious" - it has to do with the laws of chance, and of cause and effect (because I don't buy tickets). And I think the chances of traveling in time are a lot less than winning the lottery...

Well what do you think the chances are of an infinite number of angels being able to dance on the head of a pin?
posted by XMLicious at 11:23 AM on September 8, 2013


Our "past" cannot be changed. What can be changed is someone elses "present" & hence future.....or something something .
posted by asra at 11:26 AM on September 8, 2013


That is a very specific fetish....

Asking for a friend.

Basically, if you go back in time and blow away Adolph, then there's no reason for you to go back in time to kill Hitler.

Not from an individual's point of view. The interesting part isn't going back in time to kill Hitler, but what happens to the person who's gone back in time and killed Hitler. What then? The timeline has changed and what was the present day no longer exists. If the killer can go back to point in time where they left, where will that person fit in? Their parents may not have met, so does the person exist from a legal point of view? Or do you meet a you that isn't you, i.e. your parents did meet and have you, but it's not the you that travels back in time, they've lived their own life.

In short, you may save the world, but no one will remember it and you may come back a poor, penniless, homeless person that no one knows and thinks is crazy.

If you can't return to the point you left, then you're stuck in the past and known as a murderer. Jail or death may be your only option. You can't predict the future, because the past you knew no longer exists, so who knows what happens? At best, once you're out of jail, you might try to manipulate world events based on what you know could happen. Then you become a politician to shape world events on what you think they should be. So you become a Hitler of sorts.

Much better to stay home and build an Iron Man suit.
posted by Brandon Blatcher at 11:27 AM on September 8, 2013 [14 favorites]


I think some of you here need to understand that time is not a straight line so much as a ball of timey-wimey... stuff.
posted by Navelgazer at 11:29 AM on September 8, 2013 [10 favorites]


XKCD: Kill Hitler
posted by TedW at 11:29 AM on September 8, 2013 [11 favorites]


My favorite take on time travel paradoxes has always been the Sever Gansovsky story "Van Gogh", in which a couple art thieves go back to get the famous artist's art and resell it in the present. First, they buy all his art, only to discover that when they get back to the present, no one has heard of him because none of his art survived. Then they buy only some for a huge price, and still it doesn't work because now Van Gogh died a happy man and didn't produce any more art. The thieves eventually go bankrupt trying to work out a way that will actually make them money.

And now that I'm looking around, I discover there's apparently an East German film based on the story! Wow, that will be hard to track down. I may have to go back in time and buy a copy before they all disappear.
posted by jiawen at 11:30 AM on September 8, 2013 [6 favorites]


Time travel as shown on most media today is stupid. The traveller always shows up in the same location, on the planet, transposed in time. But the time interval, the earth--the whole solar system!-- has moved a considerable distance in the galaxy.

Sorry, it's a fun trope but nonsensical.
posted by notsnot at 11:30 AM on September 8, 2013 [6 favorites]


How about going back in time and buying a lot of his art and lavishing him with praise so he's not all bitter and stays out of politics?
posted by George_Spiggott at 11:31 AM on September 8, 2013 [5 favorites]


The obligatory plausible.
posted by digitalprimate at 11:34 AM on September 8, 2013


If you want to get really technical, Stephen Hawking's Chronology Protection Conjecture says that any functioning time machine would destroy itself as soon as it was turned on:
...vacuum fluctuations would drive the energy density on the boundary of the time machine (the Cauchy horizon of the region where closed timelike curves become possible) to infinity, destroying the time machine at the instant it was created or at least preventing anyone outside it from entering it.
This would be a conservation law, like the conservation of energy or mass. (No closed timelike curves.) But it's just a conjecture right now, since there's no theory of quantum gravity that could completely describe what would happen at those tiny scales.
posted by Kevin Street at 11:37 AM on September 8, 2013 [2 favorites]


Yeah, I hear Van Gogh's political career was a trainwreck.
posted by the latin mouse at 11:37 AM on September 8, 2013 [3 favorites]


lupus: So if I understand correctly, what you're saying is that killing Hitler is impossible because time travel itself is impossible. This is fair, but not really germane to the article, which is a summary of fictional works in which "time travel is possible" is part of the premise.

There are internally-consistent ways to write time-travel fiction in which altering the past is possible. You don't even really need the many-worlds model (in which Hitler still survived somewhere). Just posit that the time-traveler in the past isn't affected by his or her changes to the future, due to not being in the future when the changes are made. I'd be very surprised, for multiple reasons, if the real world worked this way, but there are plenty of time-travel stories that work this way without being "illogical".
posted by baf at 11:38 AM on September 8, 2013 [1 favorite]


I just watched Looper last night and was extremely annoyed at its incoherent take on time travel.
Incorrect, kind sir or madam!

Looper is actually pretty self consistent; it just operates on the Back To The Future theory of time travel (instantaneous ripples across all timelines), as compared to say Primer's parallel universe theory of time travel. There was a great article, possibly on io9, comparing all the different fictional theories of time travel and I highly recommend it, wherever it is.
posted by pmv at 11:47 AM on September 8, 2013 [3 favorites]


Trying to kill Hitler is such a rookie Time Traveler mistake.

Hitler *is* the result of time travel interference. All of the other, more sane and competent Fuehrers won and really did create Reichs that lasted hundreds or even thousands of years and extended the holocaust to all non-Aryan ethnic groups across the planet.

(In a few cases, the Nazi Fuehrer was replaced with someone who lost to the Soviets, but under circumstances where the Cold War quickly became a shooting war that eventually ended in a global nuclear holocaust)

As hard as it is to believe, Hitler was the least worst option. He was incompetent enough not to win, but still bad enough to give the US and Soviet Union enough pause not to initiate another war.

If you go back in time to try and kill him, you will have all the resources of a much more advanced society arrayed against you. Also, they'll know you're coming.
posted by Davenhill at 11:56 AM on September 8, 2013 [48 favorites]


Pity the poor time traveler who goes back, kills Hitler, realizes it makes things worse, and is faced with the choice of either killing his earlier self or impersonating Hitler and living out his role...

PITCH TITLE: History's Greatest Monster
posted by Artw at 12:01 PM on September 8, 2013 [13 favorites]


The Illusion of Time
posted by stbalbach at 12:01 PM on September 8, 2013 [4 favorites]


Hitler *is* the result of time travel interference. All of the other, more sane and competent Fuehrers won and really did create Reichs that lasted hundreds or even thousands of years and extended the holocaust to all non-Aryan ethnic groups across the planet.

Without spoiling by naming names, this novel has been written and published at least once that I know about, and probably only sold because the writer was a Big Name. I suspect it exists in thousands of slush piles as well.
posted by George_Spiggott at 12:03 PM on September 8, 2013 [6 favorites]


Rome, during The great fire. A mysterious, somewhat devilish figure appears in Nero's bedchambers, lays out the future and it will all end badly, posits that Nero would be happier just playing the lyre.

Eventually Nero is talked into signing a contract with the devil-like figure and departs with him through a glowing portal.

It's not the devil, it's a record producer.
posted by Artw at 12:09 PM on September 8, 2013 [3 favorites]


Of course then there's the story who has to kill a baby every day forever; it goes like this

A group of intrepid scientists discover a medium that is universally indelible and a message may be stored upon it with along with the parts of a time machine that can be used only once. However; recognizing that a paradox will happen every time one of them kills hitler someone has to maintain the timeline where hitler dies so they construct a box of the indelible material that will ALWAYS be the instructions for its use and the instruction to go to XYZ and When coordinates to kill a baby; whom the recipient (one of the scientists who will ONLY EXIST IF HITLER DIES) will receive and every day (the same day forever) he will wake up, receive the indelible material and go back in time and murder an infant he has no reason to kill, save for the message written in his own handwriting that assures him that this baby has to die.

Fun Story to write; who can do it?
posted by NiteMayr at 12:10 PM on September 8, 2013 [1 favorite]


"Time travel as shown on most media today is stupid. The traveller always shows up in the same location, on the planet, transposed in time. But the time interval, the earth--the whole solar system!-- has moved a considerable distance in the galaxy."

Pretty much every time machine in fiction is actually a spacetime machine. That is, it moves through four dimensions - a realm where space and time are just coordinates marking one's position in a higher realm.
posted by Kevin Street at 12:11 PM on September 8, 2013 [2 favorites]


How about it turns out the reason Hitler was so erratic is that time travelers kept killing him and they had to keep replacing him with hastily trained actors?
posted by George_Spiggott at 12:11 PM on September 8, 2013 [13 favorites]


What if you went back in time and made Hitler a friend with benefits?

Fuck Hitler.
posted by cjorgensen at 12:11 PM on September 8, 2013 [5 favorites]


Alonzo is correct, the instant you travel back in time, you have created a new timeline. Your old timeline still exists, so you're not actually preventing any atrocities from happening. I guess you could pat yourself on the back about how you prevented one in your new timeline, but that's kind of like laughing at your own joke.
posted by Brocktoon at 12:20 PM on September 8, 2013


I've just returned from killing Julius Caesar, the republic is saved. Who is this Hitler chap?
posted by humanfont at 12:22 PM on September 8, 2013 [20 favorites]


Alonzo is correct, the instant you travel back in time, you have created a new timeline.

PROVE IT. And show your work.
posted by Brandon Blatcher at 12:22 PM on September 8, 2013 [2 favorites]


Time Travel is basically just magic. You travel back in time and try to kill Harry Potter. Your name is Voldemort.
posted by Artw at 12:23 PM on September 8, 2013 [2 favorites]


Obligatory SMBC.
posted by Navelgazer at 12:30 PM on September 8, 2013 [1 favorite]


You can't go back in time and kill Hitler, because I've already done it. Found him in a bunker in 1945, and made it look like a suicide.
posted by blue_beetle at 12:32 PM on September 8, 2013 [5 favorites]


Jason's take (also mentioned in the io9 link) is my favorite, mainly because it skips all the physics bullshit and tells a rich and morbidly funny story about love and relationships. The Hitler angle is almost tangential.
posted by Blazecock Pileon at 12:35 PM on September 8, 2013 [1 favorite]


I prefer the Alfred Bester treatment in his story about a mad scientist from the year 1980.
posted by fifteen schnitzengruben is my limit at 12:37 PM on September 8, 2013 [1 favorite]


I contend that the best time travel story is "The Impossible Mission," from Superboy #85.

Young Clark goes back in time to rescue Abe Lincoln from his assassin. What stops him from punching out John Wilkes Booth? Another time traveler! An adult Lex Luthor, hiding in the past, encounters Superboy and paralyzes the Teen of Steel with Kryptonite! Lex wonders why Superman has pursued him into the past and considers this, while Superboy writhes in pain on the floor of Lex's room.

The light only dawns on Lex when, hearing a commotion from the street, he looks out to realize that President Lincoln is dying. Lex looks at Superboy in horror, realizing that Superboy did not come for him, but for Lincoln.

I admire the parsimony of this tale. History is conserved, by one time traveler attacking another. Thus, they are both rendered impotent: Superboy is paralyzed while Lex frets in his tiny room.
posted by SPrintF at 12:48 PM on September 8, 2013 [3 favorites]


>That is a very specific fetish....

Asking for a friend.

Basically, if you go back in time and blow away Adolph
[...]

On a quick perusal, I thought you were taking this in an unnecessarily graphic direction...
posted by GenjiandProust at 12:51 PM on September 8, 2013 [1 favorite]


What if you went back in time and made Hitler a friend with benefits?

Fuck Hitler.


Obligatory Louis C.K.

Also, apropos of Hitler but not of time travel, the New Statesman just republished this account of Hitler from 1933. It is insane. You know that weird crank at the bar who's "self-educated" and can never tell a story in one minute when fifteen minutes will do? Imagine him as a dictator.
posted by Cash4Lead at 12:52 PM on September 8, 2013 [10 favorites]




Just posit that the time-traveler in the past isn't affected by his or her changes to the future, due to not being in the future when the changes are made.

Most time travel treatments do not really work without the outside narrative thread providing a global forward-moving timeline. This is a good example of this problem, your time traveller is absent from the future in story time only.
posted by Dr Dracator at 1:13 PM on September 8, 2013


pmv: There was a great article, possibly on io9, comparing all the different fictional theories of time travel and I highly recommend it, wherever it is.

Oh, sorry, I just traveled back in time from that alternate universe and I'm afraid it doesn't exist in this one.
posted by localroger at 1:16 PM on September 8, 2013


My favorite time travel story is Timemaster, by Robert L. Forward. It's not well written, but it's the most stringent, hard sci-fi take on the subject that I've ever seen. And it's completely nuts.
posted by Kevin Street at 1:19 PM on September 8, 2013 [1 favorite]


> "... why the hell can't you travel back in time and kill Hitler?"

His kung fu was too powerful.
posted by kyrademon at 1:25 PM on September 8, 2013 [1 favorite]


PROVE IT. And show your work.

Easily demonstrated. I'll just turn on the
posted by Sangermaine at 1:27 PM on September 8, 2013 [3 favorites]


The best time travel story ever written is Michael Moorcock's Behold the Man. In addition to being brilliantly perverse it is very well written.

The one with the most solid logical underpinnings is James P. Hogan's Thrice Upon a Time. This was early Hogan before the contrarian worm ate his brain, and while it's not great literature it's put together like a well constructed puzzle and the internal logic is perfect.
posted by localroger at 1:27 PM on September 8, 2013 [5 favorites]


what about if you're trying to time travel on a budget? (self-link)
posted by The Whelk at 1:32 PM on September 8, 2013


The light only dawns on Lex when, hearing a commotion from the street, he looks out to realize that President Lincoln is dying. Lex looks at Superboy in horror, realizing that Superboy did not come for him, but for Lincoln.

Wait, what was Luthor doing there in the past on that day?
posted by Sangermaine at 1:38 PM on September 8, 2013


Hiding from Superman. History is the best hideout, from an enemy that can hear your heartbeat from space. Why he chose a boardinghouse across from Ford's Theater, I can't say.
posted by SPrintF at 1:50 PM on September 8, 2013


Hitler *is* the result of time travel interference.

Hitler survived more than two dozen assassination attempts. It's not hard to believe that someone is trying to have killed him, and that someone is keeping him from having been killed.

Time travel tenses are fun.
posted by justsomebodythatyouusedtoknow at 2:07 PM on September 8, 2013 [13 favorites]


Hitler is always being killed. The future has perfected time machines, and uses them constantly, causing the temporal narrative to be a nonsensical mess. The reason that you don't experience this change is that your life essentially back-fills from whatever change happens. The thoughts, experiences, history, knowledge that you have is constantly changing, but you're unable to get outside of the moment and realize it, and therefore have no base of comparison to understand the bleak horror that time travel has caused in human existence.
posted by codacorolla at 2:14 PM on September 8, 2013 [3 favorites]


justsomebodythatyouusedtoknow:
By that same measure, Castro must have caused some great evil in the future.
posted by Hactar at 2:17 PM on September 8, 2013


The rpg Continuum has a branch of time travelers called the Thespians. They are there to make sure that appropriate historical figures die when they are supposed to, not before or after. The number of times they have had to ask someone to play Hitler is staggering.
posted by Hactar at 2:21 PM on September 8, 2013 [2 favorites]


codacorolla, it's much simpler to suppose it's the other way around: yes, people are always going back from our future and killing Hitler, but we live in the version of events that lead up to them doing it; i.e. the one in which Hitler needs killing. They create alternate timelines that branch off from our past but can never effect the timeline that we're in.
posted by George_Spiggott at 2:21 PM on September 8, 2013 [2 favorites]


"Hitler survived more than two dozen assassination attempts. It's not hard to believe that someone is trying to have killed him, and that someone is keeping him from having been killed."

Or maybe Novikov is right, and history is self-consistent. Paradoxes just can't happen. That is, you can go back in time and try to kill Hitler, but strange coincidences and unlikely events will always stop you from succeeding.
posted by Kevin Street at 2:33 PM on September 8, 2013 [1 favorite]


So here's a variant paradox: Your friend goes back in time and whacks Hitler. He never comes back because when he returns, he returns to the future of his new timeline. Your timeline is unaffected. You then get into the time machine and travel back ten minutes earlier than he did, before he kills Hitler. The question is, does he show up, and when he does the deed you end up on the new timeline with him? Or do you end up living through your timeline of origin in which he never shows up because it never happened for you?
posted by George_Spiggott at 2:35 PM on September 8, 2013 [3 favorites]


Paradoxes just can't happen

This is what Gödel thought, according to Rudy Rucker, at least. You can go try to kill your grandfather, but it simply won't work out. The gun will jam, a car will hit you just before you fire - something will always go wrong. "Logic is powerful" explained Gödel.
posted by thelonius at 2:38 PM on September 8, 2013 [1 favorite]


Time travel as shown on most media today is stupid. The traveller always shows up in the same location, on the planet, transposed in time. But the time interval, the earth--the whole solar system!-- has moved a considerable distance in the galaxy.

This assumes there is some kind of fixed coordinate system in nature, which there isn't.
posted by ultraviolet catastrophe at 2:39 PM on September 8, 2013 [1 favorite]


(I think it's the latter. You go back to a point ten minutes before your friend did, he will never appear, because it never happened in your history and you traveled back in your history.)
posted by George_Spiggott at 2:44 PM on September 8, 2013 [1 favorite]


This assumes there is some kind of fixed coordinate system in nature, which there isn't.

No, just a relative coordinate system: relative to other astronomical objects and hence any method of navigation—since as you point out there is no fixed coordinate system either—your destination will be at a substantial distance from your origin, and besides that your body and the other contents of the time machine should have a velocity in a completely different direction from the surface of the Earth that you land on.
posted by XMLicious at 2:48 PM on September 8, 2013 [2 favorites]


Time Travel Contadictions are why this is my favorite t-shirt.

When I stumbled onto a time traveler a few years ago, I had only one request for him: to visit my great-great-grandfather when he emigrated to the U.S. and convince him to tell the immigration clerk his family name was "Wittler", not "Hitler". It made my life a lot easier.
posted by oneswellfoop at 2:54 PM on September 8, 2013 [5 favorites]


No, just a relative coordinate system: relative to other astronomical objects and hence any method of navigation—since as you point out there is no fixed coordinate system either—your destination will be at a substantial distance from your origin, and besides that your body and the other contents of the time machine should have a velocity in a completely different direction from the surface of the Earth that you land on.

But to say that I have moved, you have to say that I moved in relation to something, and therefore pick a frame of reference, and say that frame of reference is more important than the one where I seem to be perfectly still in relation to the surface of the Earth.
posted by ultraviolet catastrophe at 3:05 PM on September 8, 2013


Well if you want to get all nitpicky about coordinate systems since it seems that the Universe is expanding, if you were to travel in time you might find yourself not in the universe at all any more. Just sayin'.
posted by localroger at 3:25 PM on September 8, 2013


Nobody's mentioned going back in time to convince a young Hitler to emigrate to New York to become a really terrible science fiction writer?
posted by octothorpe at 3:29 PM on September 8, 2013 [4 favorites]


Another fun take on the trope.
posted by Evilspork at 3:30 PM on September 8, 2013 [3 favorites]


I love time travel stories as long as the power to travel in time is either a one-off, disastrously costly to do (as in, "kills thousands every time you do it") or is deeply mysterious in some way. As soon as it becomes an actual "technology" it kills the possibility of sensible story telling--it's like trying to tell a story with an ominpotent being as one of the protagonists--in the end the audience is just saying "why doesn't s/he just blink and make everything better?" I particularly hate time-travel stories where people are "racing against the clock" to do X or Y, where no one seems to think "hey, let's just go back another hour or two and do this the easy way." Dr Who suffers from this quite often, but then it always has the option of pulling out the "timey wimey" mysterious rules and constraints that you wouldn't understand unless you're a time lord card.
posted by yoink at 3:39 PM on September 8, 2013 [4 favorites]


I've got to go ask my time traveling neighbor about this. One moment.

(dee do dee dum dum)

Okay, this is what he says:

1. The multiverse theory is pretty much correct. However, the moment you change history, in any way, you basically roll dice concerning the specifics of any new timeline you end up in.

2. This is because of the nature of chaotic processes on our universe. For starters, the mere presence, absence or different movement of individual atoms ultimately affects weather patterns, and those ultimately have profound effects that are felt a long time after.

3. But in the short term, these effects are limited, because events don't have simple causes. If you are hungry and eat a sandwich, then you aren't hungry anymore. If you successfully go back in time to stop yourself from eating it (the mustard was a lot hotter than you thought it would be), you're still hungry, and will probably eat something else. Bad situations that are seen by people as bad tend to right themselves eventually, and Germany was in a very bad situation when Hitler came to power. If it hadn't been him, it might have been someone else.

4. If we are smart, the bad things that happen to us in the past inform us about the future. Without Hitler, we are all a lot less alert about the rise of charismatic tyrants, we are less concerned about the effects of racism, and we're a hell of a lot less afraid about the consequences of both global war and, eventually, nuclear weapons. These are all things that will come up later; the results, when they do, might work out even worse for some or all of humankind. As my neighbor tells me he's heard from some aliens he's met, "all developing races have to get these kinds of things out of their systems along the line, somehow." What matters is making sure the changes aren't too extreme, as sudden changes are the ones that tend to obliterate entire planets.

The results of these processes tends to give history a kind of wave-like character, oscillating back and forth between poles as people continually correct for extremes. Thwarting would-be Hari Seldons is the fact that this happens even when we don't recognize it's happening, and along a multitude of axes we don't expect, in fact recognizing it and working against it just delays the wave a bit. But the longer its delayed, the harder it crashes, the more sudden the change, the greater the suffering.

5. My neighbor admits that the precise theory of time travel he's not too up on, he just uses his own machine without understanding its operation. But he remembers hearing, just before having to run from some death cats (with their insidious purrs), that the nature of reality isn't completely multiversal. When a timeline splits, the yous on both sides of it are both still you. They have the same basic mental state, and will tend to do the same things. He calls it something like a "fractional dimension." The closer in state the two yous are, the more of each other they are, the line isn't cleanly split unless outside events decisively alter the state of one of them. What is more, when you imagine something, visualizing it in your mind, in one sense you are actually looking at a dimension in which those things happen; the process of visualization is actually a way of addressing that realm.

How accurate that last thing is I can't say (it doesn't help that my neighbor is a fan of what he calls "past pot"), but the other things I find interesting.
posted by JHarris at 4:37 PM on September 8, 2013 [8 favorites]


But to say that I have moved, you have to say that I moved in relation to something, and therefore pick a frame of reference, and say that frame of reference is more important than the one where I seem to be perfectly still in relation to the surface of the Earth.

I don't think that saying you have moved in relation to multiple astronomical bodies that aren't themselves necessarily in the same inertial frame of reference is the same thing as picking any particular frame of reference to measure within. (And besides that, it sounds like you might be conflating inertial frame of reference with rotational frame of reference - you can distinguish with certainty rotating frames of reference from non-rotating frames of reference, i.e. "not spinning" is an absolute thing, because for example in a rotating frame of reference objects that are at a certain distance from the axis of rotation appear to be moving faster than the speed of light.)
posted by XMLicious at 4:53 PM on September 8, 2013


Ha, yes, my (entirely fabricated) understanding is that 'time' is an emergent property of matter which has collected at sufficient densities. The 'dark matter' / 'dark energy' in the universe, which hasn't yet congealed into densities sufficient to be detected by us, actually exists outside of the 'time' which we perceive, and which emerges from the potentials and properties of the denser matter found in quarks, neutrinos, wave particles, etc.. If one was able to harness the admittedly chaotic process of converting their own matter to the supremely 'undense/frayed' chaotic potenial of dark matter, they would 'step outside' of time as it exists at denser levels. And since there is a continual, equibrilated flux as dark matter is condensed into matter of more determinate properties, and matter/energy of more determinate properties erodes into chaotic dark matter, one could reassemble that dark energy in any given point in our conception of 'time', without having to tweak the past too much. And then you're back into our normal conception of time, but in the past. Eeeassy pieces.
posted by notesondismantling at 5:10 PM on September 8, 2013 [3 favorites]


A similar Twilight Zone episode is Back There from 1961. A college professor discusses the Lincoln assassination with his colleagues at an exclusive Washington D.C. club on April 14, 1961. The professor gets up and bumps into an attendant at the club named William, which leaves the professor feeling disoriented as he walks out. Suddenly, the professor realizes he's been transported to Washington on April 14, 1865, the night of Lincoln's assassination. He tries to warn local police officers of the plot, but he's assumed to be a demobilized Union soldier who went crazy on the battlefield. The police later release him into the custody of a Mr. Jonathan Wellington. Wellington offers the professor a drink, which Wellington has drugged, but before the professor slips into unconsciousness, he spies Wellington's handkerchief, which has the initials JWB... for John Wilkes Booth. The professor, having failed to prevent Lincoln's assassination, awakes in 1961 and goes back to the club. When he asks for William the attendant, he is informed that no attendant named William works there. Suddenly, the professor sees William again, but this time, William is a member of the club. William is quite wealthy, but explains that his family's wealth comes from his great-grandfather, a former policeman from Washington D.C. who became famous after learning of a plot to assassinate Abraham Lincoln.
posted by jonp72 at 5:14 PM on September 8, 2013 [2 favorites]


This isn't really what XMLicious is talking about, but my (very fuzzy) understanding is that, if there was an inertial frame of reference where everything in the universe was rotating in the same way, it would be possible to travel through time by travelling through space.

That is, in a rotating universe, there would be a course through spacetime that was a timelike curve. You could blast off into space following the curve, travel who knows how far, get off to see the sights, then get back on the curve again and travel back to the point in spacetime you started from.

Unfortunately (or maybe fortunately) the universe isn't rotating. Light still follows straight lines and so on.
posted by Kevin Street at 5:21 PM on September 8, 2013 [2 favorites]


I love time travel stories as long as the power to travel in time is either a one-off, disastrously costly to do (as in, "kills thousands every time you do it") or is deeply mysterious in some way.

Ah, you just reminded me of around the end of Narbonic....
posted by jenfullmoon at 5:30 PM on September 8, 2013


what about if you're trying to time travel on a budget?

I've done this as a Halloween costume.

If you're planning to time travel a lot you won't have time and money to carefully research every time period you travel to but you'll want to be well received wherever/whenever you go. So, wear as many cultural signifiers of respectability as possible. You won't fit in in any time period, but people in a very wide range of cultures will see at least something they'll recognize.

Your anachronautical garb should at least include:

A viking horned helmet
A sword (recognized in many cultures as a mark of nobility)
A torc (gold is best, tinfoil will suffice)
A toga, over top of...
A shirt and tie (note that ties will become standard business wear for women starting in the mid 2030s)
Shiny silver pants (22nd century)
A towel

You could try some variations (substitute a panling lanshan for the toga, perhaps) but this combo should work over much of earth's history. You will get laughed at wherever you go but you will probably be tolerated as an eccentric. Even if they locals react poorly, you should get a few seconds of stunned incredulity to give you a head start running.
posted by justsomebodythatyouusedtoknow at 5:42 PM on September 8, 2013


Looper is actually pretty self consistent

The problem with Looper isn't the time travel mechanics, it's the fact that future gangsters would go to all the trouble of sending people back in time to have them killed rather than doing it in the present. They hand-wave some kind of ubiquitous biometric tracking device that makes it hard to dispose of a body, but that's ridiculous. They also say that time travel is extremely illegal in the future, so what they're really saying is that these mobsters or corporations or whatever would rather face these extreme penalties for having their time travel discovered as opposed to just incinerating a body and destroying its tracking device. I can't possibly think of a tracking device that couldn't be destroyed, and even if the concern is that the destruction itself would trigger alarms, then you still have the same problem when you shove someone with a tracker into a time machine. And even if there's some unexplained reason why time travel must be used for this, why do you send them to a certain spot in a field and hope there's someone to kill them? Send them to the middle of space! You can't possibly claim that your time travel machine can only send someone to the exact same location where it exists in the future, because that idea is patently ridiculous.
posted by Rhomboid at 6:30 PM on September 8, 2013 [5 favorites]


You can't possibly claim that your time travel machine can only send someone to the exact same location where it exists in the future, because that idea is patently ridiculous.

SPOILERS for Primer: for the duration that the box is in place, the box defines a path through space-time. Sure, the Earth is rotating, etc., but there is a continuous path in space/time between the location in the future when you get in the box and the point in the past when you come out. You know where you will arrive on your trip to the past because you defined the exit point when the box was turned on.
posted by justsomebodythatyouusedtoknow at 6:51 PM on September 8, 2013 [1 favorite]


If I could go back in time, I would stop op from using SLio9 in this post, because it makes 0 sense on any level.
posted by empath at 6:54 PM on September 8, 2013


Primer deals with the problem of the time travel device also having to be some sort of unimaginable teleportation device by making it simple. The time machine sits in a fixed location and you can only travel in time for the duration of the machine's existence; in other words the earliest you can emerge from the machine is the moment it's built.

The time machine in the Spanish film Timecrimes works the same way. (Not an especially good film but its treatment of time travel is solid.)

On preview, justsomebodythatyoususedtoknow passed me going backward in time as I went forward.
posted by George_Spiggott at 6:55 PM on September 8, 2013 [1 favorite]




I read a comment on (I believe it was) reddit not long ago on this subject. The idea was that you don't have to kill Hitler or anyone else. You go back on the night that Hitler was conceived. As Alois Hitler makes his way back home from his civil servant job, you call him by name and ask him the time. Try and strike up a conversation if possible. Ask for a light for your smoke, etc. Thirty seconds ought to be plenty. That way, Alois shows back home 30 seconds or a minute late, and the Butterfly Effect may just cascade--that very hour--enough that he and Mrs. Hitler don't in fact have conjugal relations that night. Or even if they do, the sperm that would've produced little Adolf is almost certainly beaten by some other random sperm, creating a whole new being. A girl, perhaps.
posted by zardoz at 7:09 PM on September 8, 2013 [3 favorites]


SPOILERS for Primer: for the duration that the box is in place, the box defines a path through space-time.

They must have had several boxes then, because we saw different loopers going to different locations to make their hits.
posted by radwolf76 at 7:11 PM on September 8, 2013


Is there any Hitler SciFi where someone goes back in time and acts as a mentor for young Hitler to change the way he's raised and socialized?
posted by codacorolla at 7:17 PM on September 8, 2013 [1 favorite]


A girl, perhaps.

Or someone who wasn't a vegetarian! That was the problem all along: he hated himself because he was made of meat. He wanted there to only be (veget-)Aryans, but that was just the first step.
posted by XMLicious at 7:22 PM on September 8, 2013 [3 favorites]


Because this would happen, obviously. Cue the Hell March!
posted by Apocryphon at 8:08 PM on September 8, 2013


Hitler was only vegetarian because he had Chrone's disease though, right? He didn't have any moral sentiment or conviction behind his dietary preferences, so much as health concerns.

If you suceeded in preventing Hitler's conception, then you might accidentally father him yourself. Or worse, you might end up left with no reason to want to go back in time to cock-block Hitler's papa, creating an alternate timeline that has an internal inconsistency (Hitler never even came to be, let alone coming to power, and yet, at some point the you from that timeline has to go back and prevent Hitler's birth, too, or else that timeline will have a past in which a person was created out of nothing for no reason but to prevent the conception of a person who played no significant role in anyone's history (unless the original, Hitler-ridden timeline remains running in its own thread, too, in which case, you haven't killed your own Hitler but someone else's).

Or something like that. Anyway, there are good reasons c is the universal speed limit. I don't think time travel is possible except forward. We travel forward in time every second of every day. Whether accelerating the pace of our one-way trip through time is physically possible (or advisable) or not I can't guess, but a couple of drinks can make time seem to pass more quickly. So I'll stick with subjective time travel, myself.
posted by saulgoodman at 8:16 PM on September 8, 2013 [2 favorites]


ADOLF HITLER is KILLED by SUFFOCATION WHEN INEXPLICABLY ENCASED IN AN ENORMOUS BLOCK OF UNFLAVORED GELATIN

This is going to be the name of track 1 on my forthcoming mathrock album.
posted by Gin and Comics at 11:00 PM on September 8, 2013 [1 favorite]


With no Hitler, would Israel still have come into existence? And if so, would it have have as strong?
posted by Brandon Blatcher at 2:59 AM on September 9, 2013 [1 favorite]


Artw: "Pity the poor time traveler who goes back, kills Hitler, realizes it makes things worse, and is faced with the choice of either killing his earlier self or impersonating Hitler and living out his role...

PITCH TITLE: History's Greatest Monster
"

Ummmm, well, I wouldn't be KILLING all those Jews....

[queue slap bass theme song]
posted by Samizdata at 4:39 AM on September 9, 2013


humanfont: "I've just returned from killing Julius Caesar, the republic is saved. Who is this Hitler chap?"

Who the fuck are you?
posted by Samizdata at 4:41 AM on September 9, 2013


Time travel as shown on most media today is stupid. The traveller always shows up in the same location, on the planet, transposed in time. But the time interval, the earth--the whole solar system!-- has moved a considerable distance in the galaxy.

This is probably because books or film that show the time traveller stepping forth goggle-eyed from the machine in 1865 Washington or 1666 London or whatnot are more successful than stories where the time traveller cracks the hatch and is explosively decompressed into a vacuum.
posted by ricochet biscuit at 4:46 AM on September 9, 2013 [8 favorites]


Who is this Hitler guy?
posted by Ironmouth at 5:50 AM on September 9, 2013 [1 favorite]


This is probably because books or film that show the time traveller stepping forth goggle-eyed from the machine in 1865 Washington or 1666 London or whatnot are more successful than stories where the time traveller cracks the hatch and is explosively decompressed into a vacuum.

Well, it would get a laugh out of me. Probably quite short though.

FWIW this is how "time bombs" worked in Strontium Dog.
posted by Artw at 7:01 AM on September 9, 2013


Nobody's mentioned going back in time to convince a young Hitler to emigrate to New York to become a really terrible science fiction writer?

I was going to mention The Iron Dream, but alternate history isn't really the same thing as time-travel history-meddling.
posted by Halloween Jack at 8:13 AM on September 9, 2013


So here's a variant paradox: Your friend goes back in time and whacks Hitler. He never comes back because when he returns, he returns to the future of his new timeline. Your timeline is unaffected. You then get into the time machine and travel back ten minutes earlier than he did, before he kills Hitler. The question is, does he show up, and when he does the deed you end up on the new timeline with him? Or do you end up living through your timeline of origin in which he never shows up because it never happened for you?

It depends on whether your presence in the 1940s was going to affect your friend's ability to travel back. Which means, supposing you WANT to see your friend again, you'd hide in an alley or something, and then after ten minutes, either
1) he shows up, and you therefore know you would have sufficiently stayed out of history's way
or
2) he doesn't show up and you realize that by even being here, you've changed the future enough to affect your friend somehow, probably seriously.

If the strict interpretation of the butterfly effect is to be believed, #2 is more likely.
posted by Z. Aurelius Fraught at 9:31 AM on September 9, 2013


With no Hitler, would Israel still have come into existence? And if so, would it have have as strong?

It's hard to believe that the current situation in the Middle East is the best of all possible worlds for anyone.
posted by justsomebodythatyouusedtoknow at 9:43 AM on September 9, 2013


Wow. All this 'killing Hitler' and no one mentioned that Stephen Fry (yes, that Stephen Fry) wrote a novel 'Making History', that tackled the whole 'stop the procreation' angle.
It's my favourite time travel book. Or maybe it wasn't and then someone came back from the future, sneezed, and now it's my favourite.....
posted by drinkmaildave at 9:54 AM on September 9, 2013 [1 favorite]


Twelve open tabs now, entirely about time travel, and a rapidly building list of short stories, novels, TV episodes and movies I want to consume about time travel.

I was going to do so many other things today, but that seems less interesting now.
posted by RainyJay at 9:54 AM on September 9, 2013


If you had a square circle, the angles of which added up to 270 degrees, would it be orange or pink?
posted by straight at 10:34 AM on September 9, 2013 [2 favorites]


If someone asks you the time, you might say "Noon." Then you should also answer the question "Where?" because the sun can be over only one place at any given time. But if you say "It's twelve o'clock," then you and your inquisitor may be able to agree that, at that instant, it's twelve o'clock everywhere. We get confused by all this time-zone stuff into thinking the position of the sun has anything to do with time itself. Now we learn that it's only twelve o'clock here, because elsewhere the clocks measure the illusion of the passage of time at their own subject rate. We have been asking the wrong question, but our perceptual errors don't keep us from getting the trains to run on time, so we don't care. Time is an arrow, measured by a clock.

Then we learn that the passage of time is illusory. We cannot come up with a decent analogy, because the underpinnings creating this illusion provide us conflicting versions of reality. We need another analogy. I like the Cosmic Egg Analogy. (I didn't make up the Cosmic Egg analogy, but I am running with the notion.)

Existence is a cosmic egg. We exist in an ever-present now where time is defined by the position of some unknown stylus as it tracks reality. Our perceptions, such as they are, are rooted in a physicality which has limitations that we are just now beginning to discover. We perceive time as a river because laws behind the laws of entropy create rivers, and then make up sub-rules, such as physics, which explain their flow. We get hints: gravity, for example, but the plot bones of our reality remain hidden. Entropy seems to flow in one direction, but we cannot (as yet) determine why. So time is revealed only by analogy, and spacetime is still a poor conceptual model.

We cannot lift the stylus and set it elsewhere on the cosmic egg any more than we can lift ourselves off the floor by yanking on our bootstraps. Models of time-travel are locked within the confines of the river analogy. You get to crawl out on the bank and run upstream, or run downstream, then jump in and kill Hitler or squash a butterfly, then speculate. The Creators of the Cosmic Egg laugh at our naïve presumptions. They may be able to pick up the stylus and drop it here and there on the Egg, let's say to replay our shenanigans for their own amusement, but we don't get to be aware of it. There are no infinite worlds, just the Cosmic Egg. Time doesn't pass. It doesn't flow. We live in the linear aspect defined by forces we've yet to discover, and perhaps we will exist forever. Anyhow, there's just the one egg, and we're stuck with it.

Okay, there may be an infinite number of Cosmic Eggs--you know, like a movie library--but that's another story. Put in simpler terms, Bugs Bunny can't jump off the movie screen and go into the audience.

Th-dea, the-dea, that's all folks.
posted by mule98J at 10:40 AM on September 9, 2013 [4 favorites]


It's totally possible -- Don't you see?! The timeline is a beautiful 4D pretzel of kismetic inevitability!
posted by diocletian at 10:42 AM on September 9, 2013


pmv: Looper is actually pretty self consistent; it just operates on the Back To The Future theory of time travel (instantaneous ripples across all timelines), as compared to say Primer's parallel universe theory of time travel.

The big problem with the logic in Looper (spoilers ahead) is the origin of the Rainmaker. The story culminates in the realization that the kid becomes the monstrous crime boss known as the Rainmaker because of the protagonist's intervention in the past, but the Rainmaker also exists in the original, unaltered timeline. (Well, okay, the timeline isn't exactly "unaltered", because it already contains time-travelers from the future. Not yet altered by Bruce Willis is what I mean.)

Terminator 2 had similar problems, in that the story was reliant on two contradictory notions: that traveling to the past creates self-fulfilling stable loops (Skynet being created from technology scavenged from the previous movie's Terminator), and that the future can be changed to one in which the time-travelers from the future never exist. The interesting thing, though, is that further sequels resolve this: out of narrative necessity, Skynet had to turn out not to be thwarted after all. At this point, more or less by accident, the Terminator franchise as a whole is perfectly consistent about the future being unalterable.
posted by baf at 10:42 AM on September 9, 2013 [1 favorite]


Looper is actually pretty self consistent; it just operates on the Back To The Future theory of time travel (instantaneous ripples across all timelines)

I think that word "instantaneous" has some explaining to do. (For instance, explain for the guy at the beginning who is falling apart why his limbs fall off at the moment they do instead of some other time.)
posted by straight at 10:50 AM on September 9, 2013


No fate but what we make.
posted by Artw at 11:13 AM on September 9, 2013


As always, the best way to Kill Hitler is to hire Danger 5 to do the job.
posted by gern at 11:21 AM on September 9, 2013 [2 favorites]


PITCH TITLE: History's Greatest Monster

Unfortunately there is already a Greatest Monster, and he eats cookies, so it won't fly.

And Danger 5 took six episodes to do it -- although admittedly they had to do it twice in the last episode -- and still ended with a "bum-bum-BUM!" shot of a living Hitler.
posted by JHarris at 12:46 PM on September 9, 2013


No, just a relative coordinate system: relative to other astronomical objects and hence any method of navigation—since as you point out there is no fixed coordinate system either—your destination will be at a substantial distance from your origin, and besides that your body and the other contents of the time machine should have a velocity in a completely different direction from the surface of the Earth that you land on.

Does this explain why H.G. Wells got into his time machine in London, and ended up in mid-1980s San Francisco?
posted by MoxieProxy at 2:25 PM on September 9, 2013


Help. I have accidentally opened a gate between the distant future and the begining of the universe. The result is that matter is streaming at a constant rate from the future. Physics seems to be broken. For example quantum effects and macro ones seem to be operating under different rules. The future matter appears to be throwing off a number of calculations about the velocity and position if stars, via a kind of inflationary effect. Instruments no longer detect the luminiferous aether.
posted by humanfont at 2:29 PM on September 9, 2013 [2 favorites]


Unfortunately there is already a Greatest Monster, and he eats cookies, so it won't fly.

You are correct, but the greatest monster ravages Tokyo, not cookies. To be fair, the King of the Monsters does not fly. Well, mostly not.
posted by GenjiandProust at 2:40 PM on September 9, 2013


Greatness takes many forms. Bigness, but also brilliance, importance, awesomeness. There is no need for them to compete. Maybe they could team up?
posted by JHarris at 3:29 PM on September 9, 2013 [1 favorite]


There is no need for them to compete.

The King of the Monsters does not brook rivals. On the other hand, there were those tag-teams with Rodan and Mothera.....
posted by GenjiandProust at 4:00 PM on September 9, 2013


I love all things time travel, and no time-travel thread would be complete with a link about THIS crazy story.
posted by MoxieProxy at 4:12 PM on September 9, 2013 [3 favorites]


Do not underestimate the Monster of Cookies. He looks friendly and googly-eyed, but he is canny and determined, when it's in his best interests (that is, if it involves obtaining THEM), whereas the atomic lizard mostly hangs out on Monster Island all day chilling with Minilla and Godzuki.
posted by JHarris at 4:15 PM on September 9, 2013


That is awesome MoxieProxy!
posted by JHarris at 4:52 PM on September 9, 2013 [1 favorite]


whereas the atomic lizard mostly hangs out on Monster Island all day chilling with Minilla and Godzuki.

Don't you even start with Godzuki. Can we go back to killing Hitler, please?

I would like to note that my phone really tried to have me type "Klingon Hitler" there. My phone has problems.
posted by GenjiandProust at 5:35 PM on September 9, 2013 [1 favorite]


MoxieProxy, that story was only the prototype for David Gerrold's The Man who Folded Himself.
posted by localroger at 5:40 PM on September 9, 2013 [3 favorites]


I haven't read the whole thread. Has someone mentioned the fact that the multiverse means everyone has been sent back in time to kill everyone else? And that every future person has been sent back in time to kill you? Because every thing you do, say or think--every breath you take, every move you make--will create a universe that someone (everyone!) believes must be destroyed?
posted by stargell at 8:47 PM on September 9, 2013


stipulating to the concept of achievable time travel, why the hell can't you travel back in time and kill Hitler?

Because Hitler is an idealized caricature of evil relative to our position in spacetime.
A better question is why we choose “kill” as the knee jerk response to what we believe is evil in the world and continue to dehumanize and distance “evil” as though it’s something we ourselves are incapable of no matter how many innocent, albeit destined to evil as an adult, infants we kill.
Why can’t we wrap our heads around killing as an imperfect solution and indeed, a horribly uncreative use of so powerfully creative a tool as a time machine?

Why not eliminate anti-semitism before it starts? Or ingrain tolerance, mutual respect and altruism in foundational civilizations? You have a FUCKING TIME MACHINE. Any past society would be incapable of matching the slightest influence and control you can have over every single aspect of the social environment. Eliminate money. Alter Croesus’ fall. Or hell, just rewrite the history books and credit him with inventing advanced egalitarian economies.
It’s an infinite conditioning tool. You can change the pillars of society with it.

Eliminate needless conflict and we could be in space before Leif Eriksson hits Baffin Bay.
Hitler winds up a cartoonist for the Martian Daily in a post scarcity economy, rendered irrelevant because the conditions to create the holocaust never exist.

This is simple manipulation of consciousness. Ideas. Perception. The relationships consciousness perceives between things.
Time travel concerns things: energy, physical properties. If we accept time travel as a given, the hard part is manipulating matter and energy.
The relationships, hell, that stuff never goes away.

And it’s our relationships to events that we should examine. The events themselves are secondary. What we do is what counts.

We have airplanes. Why didn’t we kill Theodore Sindikubwabo or Felicien Kabuga in Rwanda? Why aren’t we (personally) hunting people like them now?

For the most part I think even with a time machine it’s impossible to make vast sweeping changes by killing one, or even a few people, unless the moment is absolutely critical.
Even then, the changes won’t last because people live by systems and the day to day created by their social environments more than at the word of one person no matter how influential they may seem.

That’s why genocides happen. Not because it’s one evil guy, but because the day to day is such that, oh yeah, this is what we’re do now. We kick in storefronts owned by Jews. We hack to death a family because they’re “evil.” We shovel weapons at a problem and expect violence to dissipate.

Only way out of the self-correcting past or infinite multiverse is to focus on the fulcrum of the universe that is yourself and focus on (it’s cliché, but) being the change you want to see.
I mean, what’s the goal in killing Hitler? Is it the Jews specifically? Or saving lives and sparing horror? Because Genghis Khan killed so many damn people he changed the carbon footprint of the planet. His daughter (after they killed her husband) annihilated a city of 1.7 million people in 10 days. That’s women, children, babies, livestock, pets, tourists, etc. Over 7,000 an hour. Beheaded and stacked into pyramids in the streets to verify their deaths. The Mongols killed for 150 years over more than 20% of the surface of the Earth.

Some cold hearted kids out there.
What’s the solution? Machine guns?
Or maybe we need to accept change in our own society and in ourselves and thus render such evil moot immediately.
Here’s a nice time travel story with the focus on the human relationships where it belongs.
posted by Smedleyman at 9:29 PM on September 9, 2013 [8 favorites]


baf: "lupus: So if I understand correctly, what you're saying is that killing Hitler is impossible because time travel itself is impossible. This is fair, but not really germane to the article, which is a summary of fictional works in which "time travel is possible" is part of the premise."

It is not possible for me to read that word as "germane", after reading the name "Hitler".

Probably due to some future-life PTSD incident.
posted by IAmBroom at 1:34 PM on September 10, 2013


ultraviolet catastrophe: "No, just a relative coordinate system: relative to other astronomical objects and hence any method of navigation—since as you point out there is no fixed coordinate system either—your destination will be at a substantial distance from your origin, and besides that your body and the other contents of the time machine should have a velocity in a completely different direction from the surface of the Earth that you land on.

But to say that I have moved, you have to say that I moved in relation to something, and therefore pick a frame of reference, and say that frame of reference is more important than the one where I seem to be perfectly still in relation to the surface of the Earth.
"

Non-inertial frames of reference as relative, as you say, but inertial frames of reference are not.

You can argue that a bullet isn't moving through space after being fired from a gun, because you are fixed with respect to the bullet: it was fired from a gun travelling several hundred miles per hour away from you, and the firing exactly cancelled out that velocity.

But you can't argue that the bullet never accelerated, and therefore no non-inertial frame of reference exists in which the bullet and you have always had parallel paths.

The acceleration of the Earth around the Sun (due to gravity's well) must always be accounted for, no matter how you center your X,Y,Z,T coordinate system.
posted by IAmBroom at 1:49 PM on September 10, 2013 [1 favorite]


lupus: So if I understand correctly, what you're saying is that killing Hitler is impossible because time travel itself is impossible. This is fair, but not really germane to the article, which is a summary of fictional works in which "time travel is possible" is part of the premise.

The problem is that the premise is basically, "let's assume the rules of causality were different" but then you want to use the standard rules of causality to argue about what would or wouldn't result.
posted by straight at 3:34 PM on September 10, 2013 [1 favorite]


Me?
posted by baf at 11:35 PM on September 11, 2013


I don't agree with all of the analysis, but Niven's The Theory and Practice of Time Travel is an interesting exploration of the idea. It's...available online.
posted by Chrysostom at 1:59 PM on September 12, 2013


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