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Old 12-03-2018, 02:59 AM
SlackerInc SlackerInc is offline
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How quickly and pervasively would the “butterfly effect” happen after a time travel intervention?

The classic example is killing Hitler, with there being variations from assassinating him in the 1930s to actually killing him as a baby (unsettling though that idea is).

I find that people usually project out the major historical changes this would cause while assuming the same people would mostly continue to be born unless there was some clear major effect preventing this. I disagree. I think if you went back and assassinated Hitler after he became a well-known world leader, and then went back to the present*, they would find that virtually no one born ten months or more after the assassination would be the same person. Sure, many of them in that initial period would be born around the same time to the same parents, arising from the same maternal egg their alt-universe counterparts did; but to be the exact person you are requires your parents to have a very specific life course right up to the moment of intercourse, and for the man to ejaculate at that exact moment in that exact position. To read about such a dramatic event would change that at least slightly for almost everyone fairly immediately, I believe.

If the assassination were achieved in infancy, and undertaken quietly and in an unobtrusive way people marked up to natural causes, you might find when coming back to the present that there were genetically identical individuals born months or maybe years afterward. But decades? I doubt that very much, as changes ripple quietly outward.

*To avoid paradoxes including the possibility the time traveler/assassin would have their own birth negated, we’ll assume that they go back to the 21st century, but in an alternate universe instantly created the moment they arrived in the past.
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Old 12-03-2018, 04:19 AM
eburacum45 eburacum45 is offline
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This is the sort of question that I love, even though it can have no possible practical purpose.

Assuming that the timeline can be changed by a time traveller (which you do) then there is no reason for the assassin to actually kill Hitler. The mere presence of the assassin would displace air molecules, and cause a butterfly effect that would propagate across the world at the speed of sound.

How significant that effect would be is another question entirely, and I can't estimate that, though it is possible someone else might be able to do the math.
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Old 12-03-2018, 05:32 AM
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[from the trivia desk] The "butterfly effect" was a term coined by Edward Lorenz after his experiments on a Royal McBee LGP-30 computer — an antique computer with drum as its main memory that has been mentioned in another current thread.

Lorenz discovered the phenomenon when his weather simulator yielded completely different results when started with what Lorenz thought were the same initial conditions. At first he thought that the LGP-30 hardware was making arithmetic errors. He later determined that small differences in the initial conditions were soon amplified, and caused a wholly different path to be taken. In his famous paper (pdf) he concluded
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When our results concerning the instability of nonperiodic flow are applied to the atmosphere, which is ostensibly nonperiodic, they indicate that prediction of the sufficiently distant future is impossible by any method, unless the present conditions are known exactly. In view of the inevitable inaccuracy and incompleteness of weather observations, precise very-long-range forecasting would seem to be non-existent.
Lorenz is, of course, not credited with the discovery of chaos theory. That distinction is reserved for Henri Poincaré, the top mathematician of the late 19th century.
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Old 12-03-2018, 06:05 AM
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Originally Posted by eburacum45 View Post
This is the sort of question that I love, even though it can have no possible practical purpose.

Assuming that the timeline can be changed by a time traveller (which you do) then there is no reason for the assassin to actually kill Hitler. The mere presence of the assassin would displace air molecules, and cause a butterfly effect that would propagate across the world at the speed of sound.

How significant that effect would be is another question entirely, and I can't estimate that, though it is possible someone else might be able to do the math.
It depends on how deterministic the universe is. In an extreme case, if we assume the presence of true randomness and/or free will, just moving the molecules would in effect create a new universe, which will move forward in a manner completely different from the "previous" one. Every coin flip or dice roll could have a different result, every decision could be different.
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Old 12-03-2018, 07:02 AM
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I don't believe in the idea of a Clockwork Universe. If a time traveler were to go back to a particular date, I think it has the effect of restarting the timeline from that date, and all events that follow may be different based on natural randomness of action.

For example, if the timeline were restarted before a game of Monopoly, would every subsequent throw of the dice be identical from the first playing? I see no reason why it should be. If it was, then one should be able to predict every throw of that game from the initial conditions, since that is exactly where we are resetting the timeline.

Some things may stay the same, if you restart the timeline in 1975, Microsoft might still wind up a big deal, but there's little chance for Google since the two founders would have been babes, and it's unlikely that they would come together many years later to create the same company as the first time around.
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Old 12-03-2018, 07:08 AM
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Well, we know that the weather can be completely different after two weeks, from just a butterfly's perturbation. If we assume that a time traveler causes a larger perturbation than a butterfly, then it'll take no more than two weeks from the time traveler's arrival for the weather to be completely different.

Now think about all of the things that the weather can affect. We don't know exactly how chaotic human interactions are, but we do know that weather is one of the inputs to human interaction, so the whole system must be at least as chaotic as the weather.
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Old 12-03-2018, 07:23 AM
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In dynamical systems theory, one can speak of the Lyapunov exponent or Lyapunov time which describes how rapidly nearby trajectories diverge. But you will have to formally define your system to pin the time down even within a few orders of magnitude. (What Chronos said.)
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Old 12-03-2018, 07:57 AM
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if you believe , with Robert Forward, that any apparent changes you make are bound up in the system (that is, they aren't really changes, but were always part of the time-stream of reality), then there's no delay at all, no matter how you measure it.

Time travel changes take observable "time" to propagate through , well, time in movies like the Back to the Future series (with those fading in-and-out newspaper headlines and markings on tombstones) or throughout the film* A Sound of Thunder in order to build dramatic tension, and to show the time travelers who screwed up the timeline of their own reality that they have to get to work and fix it. It's not because the filmmakers have some Grand Theory of Time Travel that posits how ripples in the time stream propagate through time.


*but not in Ray Bradbury's original story. In his story, as in most science fiction of the time, effects of time travel are "instantaneous".
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Old 12-03-2018, 07:59 AM
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Originally Posted by Alessan View Post
It depends on how deterministic the universe is. In an extreme case, if we assume the presence of true randomness and/or free will, just moving the molecules would in effect create a new universe, which will move forward in a manner completely different from the "previous" one. Every coin flip or dice roll could have a different result, every decision could be different.
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I don't believe in the idea of a Clockwork Universe. If a time traveler were to go back to a particular date, I think it has the effect of restarting the timeline from that date, and all events that follow may be different based on natural randomness of action.
I'm not disagreeing with you, but I feel compelled to point out that the point of the "butterfly effect"/chaos theory is that, even if the universe were completely deterministic, a seemingly minor change could result in a very different universe.
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Old 12-03-2018, 08:47 AM
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Originally Posted by Thudlow Boink View Post
I'm not disagreeing with you, but I feel compelled to point out that the point of the "butterfly effect"/chaos theory is that, even if the universe were completely deterministic, a seemingly minor change could result in a very different universe.
I know. I mean, I may not know much about math or physics, but I know that counter-intuitive as it may sound, "chaos" is not the same as "randomness".

Last edited by Alessan; 12-03-2018 at 08:49 AM.
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Old 12-03-2018, 08:59 AM
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This is the sort of question that I love, even though it can have no possible practical purpose.

Assuming that the timeline can be changed by a time traveller (which you do) then there is no reason for the assassin to actually kill Hitler. The mere presence of the assassin would displace air molecules, and cause a butterfly effect that would propagate across the world at the speed of sound.

How significant that effect would be is another question entirely, and I can't estimate that, though it is possible someone else might be able to do the math.
I agree with almost all of this, but I’m not sure you can assume that any “butterfly” change will neutralize Hitler, at any stage. I’m not sure just popping in and breathing a few breaths or whatever at the Nuremberg rallies will keep him from doing some bad stuff. I would be sure such a “pop-in” would make 2018 quite different from what it is in our timeline, but the 1930s and 1940s might be fairly similar.
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Old 12-03-2018, 09:05 AM
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Given that as far as we know time travel is impossible, there is no way to answer this factually. Off to IMHO.

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Old 12-03-2018, 09:39 AM
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It depends on how deterministic the universe is. In an extreme case, if we assume the presence of true randomness and/or free will, just moving the molecules would in effect create a new universe, which will move forward in a manner completely different from the "previous" one. Every coin flip or dice roll could have a different result, every decision could be different.
If we assume the presence of true randomness and/or free will, then you would create a new universe which would move forward in a manner completely different from the "previous" one simply by starting again from a prior point, even if no molecules at all were moved. (This is basically the "many worlds" interpretation of quantum theory.)

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Well, we know that the weather can be completely different after two weeks, from just a butterfly's perturbation.
We know it? The butterfly effect is a whimsical metaphor to describe an aspect of chaos theory, but it emerged from mathematical models. Do scientists think that the flap of a butterfly's wings can literally cause a significant change in the weather at a distant location weeks later?
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Old 12-03-2018, 10:10 AM
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As much as I enjoy a good time travel story, where the changes are just a little off, like BTTF, the reality would most likely be 100% change. Go back to 1920 and kill Hitler, and 2018 would be unrecognizable. Not only would millions live that died before, millions would not be born who were now born. No one living on your street now would be there, most likely even the buildings wouldn't be the same. Human nature being what it is, you could probably learn to assimilate, but you'd stick out. You'd ask someone where the Circle K is and they'd look at you funny, and you'd see job ads for "mystellogist" and "urban seamripper" and have no clue.

The state of technology might be far ahead of us currently, or far behind. There might be electric cars with vacuum tube radios. There might be no nuclear weapons, but Europe might be at war this very day.

In TNG's Tapestry, where Q does a do-over on Picard's life, and shows him the kind of change this thread is about, I wept* for all the billions of people born in the alternate timeline who simple never were once Q reset the timeline. What happened to all those people? They had entire lives in the years between the events. They lived, loved and died during those years. Did their lives have meaning after Q "never-wered" them out of existence again? Will no one remember them?


*figuratively speaking, of course

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Old 12-03-2018, 10:17 AM
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The classic example is killing Hitler, with there being variations from assassinating him in the 1930s to actually killing him as a baby (unsettling though that idea is).

I find that people usually project out the major historical changes this would cause while assuming the same people would mostly continue to be born unless there was some clear major effect preventing this. I disagree. I think if you went back and assassinated Hitler after he became a well-known world leader, and then went back to the present*, they would find that virtually no one born ten months or more after the assassination would be the same person. Sure, many of them in that initial period would be born around the same time to the same parents, arising from the same maternal egg their alt-universe counterparts did; but to be the exact person you are requires your parents to have a very specific life course right up to the moment of intercourse, and for the man to ejaculate at that exact moment in that exact position. To read about such a dramatic event would change that at least slightly for almost everyone fairly immediately, I believe.

If the assassination were achieved in infancy, and undertaken quietly and in an unobtrusive way people marked up to natural causes, you might find when coming back to the present that there were genetically identical individuals born months or maybe years afterward. But decades? I doubt that very much, as changes ripple quietly outward.

*To avoid paradoxes including the possibility the time traveler/assassin would have their own birth negated, we’ll assume that they go back to the 21st century, but in an alternate universe instantly created the moment they arrived in the past.
Well, a couple of things. First off, my own opinion is that if you were go to back in time to kill Hitler you'd basically be splitting off from our timeline and essentially creating a new universe or timeline. Coming back to this one would basically be exactly the same as when you left. Going back to this time in the new timeline would be substantially different.

I agree that many people born around that same time would have different lives...how could they not? Either there would be no WWII or it would be substantially different, with even the combatants being different (perhaps the USSR and some others against the UK and France with the US being neutral or something along those lines). People who died in our timeline might live in the new one, and vice versa. By the time we are talking about 70+ years later the world would be completely different...really, unrecognizable to the time traveler if he moved forward in the new timeline.
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Old 12-03-2018, 10:55 AM
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In TNG's Tapestry, where Q does a do-over on Picard's life, and shows him the kind of change this thread is about, I wept* for all the billions of people born in the alternate timeline who simple never were once Q reset the timeline. What happened to all those people? They had entire lives in the years between the events. They lived, loved and died during those years. Did their lives have meaning after Q "never-wered" them out of existence again? Will no one remember them?
Here's a chilling thought - what if we're those people? Maybe this timeline is a mistake created by bumbling or malicious time travelers, and one day a hero will jump back and delete us all from existence.
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Old 12-03-2018, 10:59 AM
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Although Lorenz coined the term "butterfly effect," he may have been inspired by the 1952 science fiction story by Ray Bradbury, mentioned above by CalMeacham:

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Somehow, the sign had changed:
...
Eckels felt himself fall into a chair. He fumbled crazily at the thick slime on his boots. He held up a clod of dirt, trembling, "No, it can't be. Not a little thing like that. No!"
Embedded in the mud, glistening green and gold and black, was a butterfly, very beautiful and very dead.
"Not a little thing like that! Not a butterfly!" cried Eckels.
It fell to the floor, an exquisite thing, a small thing that could upset balances and knock down a line of small dominoes and then big dominoes and then gigantic dominoes, all down the years across Time. Eckels' mind whirled. It couldn't change things. Killing one butterfly couldn't be that important! Could it?
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In dynamical systems theory, one can speak of the Lyapunov exponent or Lyapunov time which describes how rapidly nearby trajectories diverge....
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... Do scientists think that the flap of a butterfly's wings can literally cause a significant change in the weather at a distant location weeks later?
Replace "weeks" with "centuries" and you'd have no doubt of the validity, right? Until we estimate the Lyapunov exponent DPRK refers to, we are just (to paraphrase Lord Beaverbrook) haggling over the price.

Last edited by septimus; 12-03-2018 at 11:02 AM.
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Old 12-03-2018, 11:22 AM
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I agree that many people born around that same time would have different lives
I think the OP's point is that they'd be different people. If your conception had been timed just a little bit differently, it would have involved different sperm and/or eggs, and thus a different you.
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Old 12-03-2018, 12:12 PM
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Given that as far as we know time travel is impossible, there is no way to answer this factually. Off to IMHO.

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The answer is obviously m[χ]σ/2π, where m[χ] is the rest mass of the chronoton, and σ the subspace field constant. God, people!
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Old 12-03-2018, 12:19 PM
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Replace "weeks" with "centuries" and you'd have no doubt of the validity, right? Until we estimate the Lyapunov exponent DPRK refers to, we are just (to paraphrase Lord Beaverbrook) haggling over the price.
I have doubt of the validity of this applied to large complex physical systems like weather (not mathematical models of weather). But I am not a chaos theory expert or even a mathematician.
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Old 12-03-2018, 12:57 PM
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I think the OP's point is that they'd be different people. If your conception had been timed just a little bit differently, it would have involved different sperm and/or eggs, and thus a different you.
Not in a few months or even a few years...after that though, sure. Other things would have greater impacts that would become cumulative over time. It would certainly be a vastly different world, fast forwarding to today, and I'd guess that none of the people alive today would be alive in the alternative timeline.
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Old 12-03-2018, 02:56 PM
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I go with the many worlds theory. We already have developed time travel several times but the inventor went back and changed something thereby creating yet another "many world" with a new timeline conforming to those events. This all leaves our timeline intact and with no knowledge of time travel because the inventor will never be seen in our world again.
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Old 12-03-2018, 03:14 PM
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Honestly, I think it would be huge, pretty quickly. Let's say Hitler's killed as a baby. The baby boom might never happen, and even if you delayed people a few seconds from doing the deed, whole other sets of people would be here, or never born. Plus, assuming ww2 never happens, potentially millions of people who died would not have. It would be massive, massive changes, for better or worse.
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Old 12-03-2018, 03:48 PM
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People talking about the impacts of World War II are missing the scale of the problem. Stopping World War II would obviously change everything, but so would just going back, stepping out of your time machine, sneezing once, and then returning. Anyone conceived more than (at most) a week after that event would be the result of a different sperm cell winning the race, and thus a completely different person. And of course if you re-run history with a completely different set of people, the course is going to be different.
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Old 12-03-2018, 03:59 PM
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People talking about the impacts of World War II are missing the scale of the problem. Stopping World War II would obviously change everything, but so would just going back, stepping out of your time machine, sneezing once, and then returning. Anyone conceived more than (at most) a week after that event would be the result of a different sperm cell winning the race, and thus a completely different person. And of course if you re-run history with a completely different set of people, the course is going to be different.
I kinda sorta follow the principle but not this particular example. How is a sneeze going to affect anyone conceived within a week? I could see how if you stop to ask someone directions it could affect the conception of his child, but "anyone" is pretty sweeping especially if you didn't even sneeze on anyone, and the scope of such impact would be pretty limited geographically. Your sneeze in Hoboken isn't going to have any impact on that couple who just went to bed in Sydney.
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Old 12-03-2018, 04:16 PM
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I kinda sorta follow the principle but not this particular example. How is a sneeze going to affect anyone conceived within a week? I could see how if you stop to ask someone directions it could affect the conception of his child, but "anyone" is pretty sweeping especially if you didn't even sneeze on anyone, and the scope of such impact would be pretty limited geographically. Your sneeze in Hoboken isn't going to have any impact on that couple who just went to bed in Sydney.
Jim in Hoboken is distracted by your sneeze so he walks little slower for half a step, he is now a little off. Everybody he encounters on his way to work will also move slightly differently and will also be off. Everybody all these people encounter will also be slightly off. Somebody who is slightly off is going to call their grandparents in Adelaide who will then affect everyone around them. It won't take long before everybody is somewhat off-kilter. Big changes like getting the right lottery ticket from a lucky dip or not will also add localised extra bangs which will again speed up the ripples.
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Old 12-03-2018, 04:16 PM
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I go with the many worlds theory. We already have developed time travel several times but the inventor went back and changed something thereby creating yet another "many world" with a new timeline conforming to those events. This all leaves our timeline intact and with no knowledge of time travel because the inventor will never be seen in our world again.
Unless we’re the other world, the world he arrived in.
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Old 12-03-2018, 05:18 PM
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I think the OP's point is that they'd be different people. If your conception had been timed just a little bit differently, it would have involved different sperm and/or eggs, and thus a different you.

Yes, quite right.


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Although Lorenz coined the term "butterfly effect," he may have been inspired by the 1952 science fiction story by Ray Bradbury, mentioned above by CalMeacham:

Yes, this was always how I thought of it (having read that story at a pretty young age). I didn’t realize this was not a universally agreed-upon interpretation.

Of course, in the Bradbury story, it’s actually taken in a direction whose specifics I don’t really buy, despite their “cool factor”. They don’t go with the “many worlds” theory, so they show things as changing even within the time travelers’ lives. They act as though walking on elevated walkways and not touching anything in dinosaur times would not alter the future, when I agree with those who say even a couple sneezes would do it (though I think they might be overestimating how quickly those changes would ripple through). And in that story, the protagonist comes back and finds some of the letters in the alphabet are different, but the same two candidates are running in the election, with the “bad” one winning in the altered timeline. There’s no way so much would be different and simultaneously so much the same.


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People talking about the impacts of World War II are missing the scale of the problem. Stopping World War II would obviously change everything, but so would just going back, stepping out of your time machine, sneezing once, and then returning. Anyone conceived more than (at most) a week after that event would be the result of a different sperm cell winning the race, and thus a completely different person. And of course if you re-run history with a completely different set of people, the course is going to be different.

So you think a sneeze makes every conception, even those thousands of miles away, different within just a week? I am sympathetic to the general thrust of this argument, but you might be a little more radical than I am. I feel like it might take a few months in that case. Although I suppose maybe it would start to get exponential? That’s probably the argument you’d make, and I could see that.

I do think history rerun with different people would still get us to a similar point, though. There would presumably be changes in terminology (I love JAQ’s “urban seamripper”), but I’m not convinced we could go so far as to get to the 21st century without nukes, or even without something pretty similar to an iPhone even if it is called something different. I’m open to persuasion on this though.

Last edited by SlackerInc; 12-03-2018 at 05:21 PM.
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Old 12-03-2018, 06:42 PM
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Originally Posted by SlackerInc View Post
The classic example is killing Hitler, with there being variations from assassinating him in the 1930s to actually killing him as a baby (unsettling though that idea is).

I find that people usually project out the major historical changes this would cause while assuming the same people would mostly continue to be born unless there was some clear major effect preventing this. I disagree. I think if you went back and assassinated Hitler after he became a well-known world leader, and then went back to the present*, they would find that virtually no one born ten months or more after the assassination would be the same person.
Yes, absolutely agree. Given that we were born because a specific sperm out of millions (or dozens of millions? Don't know) reached the egg, the slightest change in the father's day (a slightly different body movement at some point, for instance) would result in someone else (or maybe nobody) being born. Even if you killed a completely anonymous person, newborns would be different people all over the planet within some years and history would change completely as they age.
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Old 12-03-2018, 07:03 PM
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So you think a sneeze makes every conception, even those thousands of miles away, different within just a week? I am sympathetic to the general thrust of this argument, but you might be a little more radical than I am. I feel like it might take a few months in that case. Although I suppose maybe it would start to get exponential? That’s probably the argument you’d make, and I could see that.
It takes two weeks for weather all around the globe to be completely different. And the weather being different would certainly be enough for different conceptions. That's just the upper bound for the timescale involved. To be honest, I'm inclined to agree with eburacum45 that it'd actually only take a time corresponding to the speed of sound.
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Old 12-03-2018, 09:00 PM
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My understanding of the butterfly effect is that small random events can have an effect on a larger scale not that they must.

The problem with weather prediction is that there millions of small random events happening on any given day so the cumulative effect of them is what causes the unreliability of forecasting models. So one butterfly flapping his wing may effect the weather or it maybe simply be an inconsequential event that won't effect weather at all.

So stepping out of a time machine, sneezing, and then returning is unlikely to cause major changes depending on where it happens. I mean if I went back to 1800 to the South Pole and sneezed, the chances of it having any major effect on the timeline is highly unlikely in my opinion.
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Old 12-04-2018, 06:11 AM
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The last two posts lay out the contours of a fascinating debate! I’m all the more intrigued because I’m honestly not sure who’s right.
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Old 12-04-2018, 07:21 AM
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If we’re stepping out of time machines, sneezing, then returning home, maybe we ought to rename it The Gesundheit Effect.
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Old 12-04-2018, 09:30 AM
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One could postulate that sneezing is not required. the simple act of being there should be enough.

When you arrive in the past, you displace the air there. You cause a slight increase in air pressure, which will radiate out. Stepping on grass alters the local wind resistance. Stepping on snow at the south pole creates a local warm spot, which could lead to melting of the glacier in a cascade effect.

My theory about the Guardian of Forever isn't that some giant cataclysmic war destroyed the civilization on that planet, but someone on that planet used it and did the equivalent of stepping on an ancient butterfly. The Guardian survives because it exists outside of time. And that butterfly effect is "still" affecting the universe, and Earth as well. Earth almost got destroyed. Spock was never born, and some Andorian was the first officer of the Enterprise.

It's just best to stay home. Too dangerous!
  #35  
Old 12-04-2018, 10:09 AM
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The last two posts lay out the contours of a fascinating debate! I’m all the more intrigued because I’m honestly not sure who’s right.
I believe there are many events that would lead to profound changes world-wide. Killing baby Hitler being one example.

But, I also believe there are many events that would have little to no effect on a large scale. Sneezing on the North pole being one example.

It’s the types of events between these two extreme examples where I believe things can go either way.

Let’s take, as an example, a guy walking down the sidewalk who in this timeline is going to impregnate his wife in one weeks' time and she will have a baby named Billy 9 months later.

Let’s make an alternate timeline, with the only change being that the guy stops for 15 seconds to look at a bird. He then proceeds on his way to his original destination.

Will stopping to look at the bird change the baby in any way?

Well, it could—perhaps that 15 second delay causes the guy to be crushed by an anvil that falls from a second floor window as he passes under.

Or, if the guy was on his way to impregnate his wife immediately after his walk, I believe his sperm may be arranged a little differently due to the delay causing Billy to be someone else.

But, the guy isn’t on schedule to knock up his wife for another week. There will be many events occurring in this guy’s life before he and his wife do the baby-making bumping of uglies. Maybe the first event after his walk was a little delayed, but he got back on schedule for the event after that … and all the events after that were on schedule and unaffected by the bird-watching delay.

So, when the couple climb into bed and have sex on the fateful evening, are the 2 timelines out of sync in any way one week after the changed event? Not unless the guy picks that time to tell his wife about the weird-looking bird he saw and she falls asleep. Otherwise, I believe 2 Billies will be born with identical DNA.

In this case, the more time between the changed event and the resultant outcome caused self-correction and re-syncing. That’s how I see it, anyway.
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Old 12-04-2018, 10:36 AM
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I can’t agree with that. I seriously doubt the same sperm will fertilize that egg (which will be the same) unless his every motion over that week was identical. Even if the change doesn’t occur until partway through intercourse, his ejaculating a millisecond earlier or later, or in a position that is changed by a millimeter, will totally change which sperm (if any) gets to the egg.
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Old 12-04-2018, 11:22 AM
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People talking about the impacts of World War II are missing the scale of the problem. Stopping World War II would obviously change everything, but so would just going back, stepping out of your time machine, sneezing once, and then returning. Anyone conceived more than (at most) a week after that event would be the result of a different sperm cell winning the race, and thus a completely different person. And of course if you re-run history with a completely different set of people, the course is going to be different.
I'm not sure I agree with you. There is something to be said for the 'sweep of time'. Hitler didn't factor in World War I, which set the stage for a desperate and angry Germany. Arguably, SOMEONE would have set that match on fire, even if Hitler was never born.

And inconsequential things happen all the time. Like, ALL THE TIME. Things may be different, but the 'averaging' of events would tend to bring larger movements together regardless of the introduction of a sneeze or not.
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Old 12-04-2018, 11:51 AM
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I'm not sure I agree with you. There is something to be said for the 'sweep of time'. Hitler didn't factor in World War I, which set the stage for a desperate and angry Germany. Arguably, SOMEONE would have set that match on fire, even if Hitler was never born.

And inconsequential things happen all the time. Like, ALL THE TIME. Things may be different, but the 'averaging' of events would tend to bring larger movements together regardless of the introduction of a sneeze or not.
Right, but even if WWII still ended up happening, but in a slightly different way, it still would cause massive changes. Certainly having a whole different leadership with likely at least slightly different timelines would result in massive changes.
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Old 12-04-2018, 02:10 PM
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I have it on good authority that someone stepped on a butterfly hunting a Dinosaur and that's how Trump won in this timeline.
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Old 12-04-2018, 05:49 PM
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I don't believe in the idea of a Clockwork Universe. If a time traveler were to go back to a particular date, I think it has the effect of restarting the timeline from that date, and all events that follow may be different based on natural randomness of action.

For example, if the timeline were restarted before a game of Monopoly, would every subsequent throw of the dice be identical from the first playing? I see no reason why it should be. If it was, then one should be able to predict every throw of that game from the initial conditions, since that is exactly where we are resetting the timeline.

Some things may stay the same, if you restart the timeline in 1975, Microsoft might still wind up a big deal, but there's little chance for Google since the two founders would have been babes, and it's unlikely that they would come together many years later to create the same company as the first time around.
This. The chance of any one specific individual emerging from any given reproductive act may not be "Lottery Odds," but it's probably in the ballpark.

For example, killing baby Hitler via time travel doesn't get the Austro-Hungarian Empire out of the Balkans, but Gavrilo Princip probably doesn't get to take the shot at Archduke Ferdinand. Still, the Serbian movement might still get him, using someone else willing to be a martyr for the cause, and you might still have WWI; the politics/culture/social pressures were still there.

SO let's say WWI goes ahead, along the same general lines as original timeline. Does the Triple Entente still win? Does Kapitänleutnant Walther Schwieger of the U-20 still sink the Lusitania, bringing America into the war? After all, he may (probably) now has a different weapons officer, and maybe this time his firing solution is off, and misses the Lusitania. Or, being low on fuel (like in the original timeline), he instead decides to return to port for resupply, thereby missing the Lusitania entirely.


Neat fodder for alt-history fans.
  #41  
Old 12-04-2018, 08:02 PM
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Whatever else, if we went back and killed Hitler when he was a baby, we might all still be enjoying the aesthetic design of the swastika, and Hipsters the world over might all be sporting toothbrush mustaches.
  #42  
Old 12-06-2018, 01:17 AM
clairobscur clairobscur is offline
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I go with the many worlds theory. We already have developed time travel several times but the inventor went back and changed something thereby creating yet another "many world" with a new timeline conforming to those events. This all leaves our timeline intact and with no knowledge of time travel because the inventor will never be seen in our world again.
I find the many world theory absolutely depressing. It removes any hint of free will (I don't believe in free will, but I believe that I'm the physical process that determines my actions) and even the hope of randomness, since every single thing we can do, we will do, every single thing that can happen to us, will happen to us, every single possible future will take place. I will thrown myself out of the window in five minutes, I will also drink a full glass of vinegar and sing the Orfeo of Monteverdi. China will launch a missile on Paris and a stranger will knock at my door to offer me a suitcase full of € 500 bills.


On top of it, the idea sometimes advanced that in a many world...multiverse... we will live forever makes complete sense to me. Which is not exactly an uplifting concept, because it doesn't guarantee a healthy and pleasant life, at the contrary (while you're dying from cancer, some freak event keeps you alive, but still on the verge of death is more or less how it would work for the overwhelming majority of future "you"), and you're going to still be around during the umpteenth billions of years during which the universe will slowly get dark and "dies". The only positive point is that the vast majority of "me" will be unconscious most of the time but...some won't
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Old 12-06-2018, 02:12 AM
nightshadea nightshadea is online now
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this reminds me of a what if that was in a scholastic history magazine

it was "what if the great depression never happened" and it was postulated that tech wise wed be in the mid 80s germany and eastern Europe thewould be equilivent of todays japan and china thered be no Nazis because things would be outsourced to them and every one would have jobs and money (hitler would be the artist he wanted to be and considered "eccentric")


ww2 would be a few atomic bombs lobbed to the ussr and be over in mere weeks


but since thered be none of the infrastructure building the depression and ww2 spawned wed be at the same spot we were in the teens and 20s …..and in a permanent semi recession....

Last edited by nightshadea; 12-06-2018 at 02:14 AM.
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Old 12-06-2018, 10:12 AM
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I really wanted that Urban Seamripper job.
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Old 12-06-2018, 10:49 AM
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I personally hate the mutil-verse theory. Larry Niven put it best (from memory): Remember that decision you had to make that was really important? How hard you agonized over it? Well, an infinite number of you decided the exact opposite. And an infinite number of you still haven't decided!

If every decision choice goes both ways, there's no point to anything. But actions DO have consequences. As messed up as our universe may be, realize there would be an infinite number where everyone is a violent criminal.

Last edited by Just Asking Questions; 12-06-2018 at 10:50 AM.
  #46  
Old 12-06-2018, 02:04 PM
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I'm of the opinion that anything other than extreme time travel interventions will basically regress to the mean. If you butterfly away Einstein, then someone else comes up with relativity. If our universe is the middle of the bell curve, the new universe won't be exactly the same, but it will likely not be standard deviations away.
  #47  
Old 12-06-2018, 02:15 PM
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I'm of the opinion that anything other than extreme time travel interventions will basically regress to the mean. If you butterfly away Einstein, then someone else comes up with relativity. If our universe is the middle of the bell curve, the new universe won't be exactly the same, but it will likely not be standard deviations away.
I think Einstein might not be the best example. Relativity was not like many other independent discoveries or inventions. Somebody might have come up with relativity but it could have taken years--and then maybe the atomic bomb would not have been available for WWII.
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Old 12-06-2018, 03:15 PM
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Someone else would have come up with Special Relativity, at most a couple of years after Einstein did. General Relativity, however, would probably have taken decades.
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Old 12-06-2018, 03:43 PM
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I think people confuse the general and the specific.

Killing Hitler might still lead to a reality where WWII happened, nuclear weapons were invented, General relativity was theorized, the cold war happened, and some buffoon was elected President in 2016.

But everyone will be different. Different people will have lived and died. Time travel to 1920 kill Hitler and return and it is near 100% that no one will ever have heard of you. Your parents will have never met. Your office and job might be there, but no one you know will be working there.
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Old 12-06-2018, 05:23 PM
SlackerInc SlackerInc is offline
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I'm of the opinion that anything other than extreme time travel interventions will basically regress to the mean. If you butterfly away Einstein, then someone else comes up with relativity. If our universe is the middle of the bell curve, the new universe won't be exactly the same, but it will likely not be standard deviations away.

I agree generally with JAQ, but I would add that although technology might be similar, every movie, song, novel, and artwork would be different. And that would feel like a very different society. I think over time, that would cause the cultural differences to pile up more and more.
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