What's the difference between the AB1 timeline and the CD timeline? Once the person leaves from point B, he creates point C, time progresses to point D, where the time trip is either confirmed or not. How does he leave at point B and end up in point A1 instead of C? What's the difference between point A1 and C?
...I'm not in the AB history. The AB history is the original history. Since Reese and the Terminator have already come back, I'm obviously not in the original history, no matter how many numbers you put after it.
O.K., obviously you're missing something I think is quite obvious, so let me see if I can make it obvious.
In 2000 Abe starts building a time machine; that's point A. In 2010, point B, Abe travels to 2000, which becomes point C because Abe is in it, and he wasn't before. Eventually we reach point D, 2010, and if we're lucky, nothing changed significantly for Abe, who has been working on his time machine and leaves for 2000, and we have an N-jump. You've got that straight, right?
So now in 2020 Bob starts building a time machine. Bob doesn't have to know anything about Abe's time machine, but maybe he does, it doesn't really matter. This is point A for Bob, because in 2030 Bob has finished his time machine, and at his point B he travels back to point A, which for him is 2020 and becomes point C, and we hope that he, too, will avoid any interference that prevents his counterpart from building the time machine which will take him back to point C, and we'll have another N-jump.
You'll note that there is absolutely no correlation here between Bob's time trip and Abe's time trip.
Now let's change it a bit. Abe's trip happens just like I said, but in 2005 Bob starts working on his time machine and by 2015 Bob makes his trip from his point B to his point C, which is in 2005. What we have here is overlapping anomalies, and time moves something like this:
From Abe's A through Bob's A to Abe's B, where Abe interrupts Bob's AB timeline by traveling back to Abe's C, undoing everything Bob has done to this point; but when 2005 comes around Bob's A happens again inside Abe's CD timeline because Bob has not yet traveled to the past. Then we reach Abe's D, and we'll assume an N-jump, and five years later we reach Bob's B, and Bob travels back to his C, which is inside Abe's CD timeline, changing the history of that anomaly. Assuming Bob does not interfere with Abe, Abe's D will arrive again and we will have the anticipated N-jump of Abe's anomaly, and then time will continue until we reach Bob's D, where we have the other N-jump.
That assumes everything goes smoothly, and that the two time travelers do not interfere either with themselves or with each other. It gets much more complicated if they do.
Kyle Reese did not make the same trip as the T-800. He did not leave at the same moment; he did not arrive at the same moment. That means that both of them lived through the AB timeline of the T-800, and then when the T-800 traveled to the past they both lived through the CD timeline of the T-800. That anomaly must have resolved into an N-jump, because otherwise Kyle could never have left from the future (it would not have existed). But when Kyle leaves, he puts an end to his own AB timeline which overlaps the T-800's CD timeline, creating a second anomaly that interacts with the first anomaly. It happens that the two anomalies interact in a manner that causes an interlocking sawtooth snap--one of the most complicated and difficult of all anomalies to track, as each anomaly makes changes in the other. Fortuitously it eventually plateaus and stabilizes such that we get N-jump endings for both, and time continues beyond that, and for our purposes we're going to treat them as if they were just simple N-jumps, that the CD histories stabilized.
At some point in the future SkyNet is going to send another terminator back to kill you. (That's not giving anything away, is it?) When it does so, that trip will create a new anomaly, which means there will be an original AB history (through which you will have lived but then forgotten entirely) and then a replacement CD history. If you then send something back to assist yourself in the past, that will create yet another anomaly, erasing the AB history that is part of the CD history of the T-1000 which is part of the CD history of Kyle which is part of the CD history of the T-800. Each of those is its own separate anomaly.
If you summon someone from the future, your prayer creates point A of the anomaly which will be created at point B when that traveler departs for the past; he will create his own point C within the CD timelines already established, and you'll have to make sure that at point D in his anomaly his counterpart makes the same trip for the same reason.
So the reason there are the numbers is that it's a lot easier than saying "Abe's A", "Bob's C", "D of Abe's third anomaly", and so on. I simply give a number to each separate anomaly and identify them that way. It is possible for different designations to identify the same point, as for example if Abe travels from 2010 to 2000 and then Bob travels from 2015 to 2000, with the result that Abe and Bob arrive at the same moment, and thus that their points C are the same (although their points B and D are different), but they are parts of different anomalies: Bob cannot reach Abe's A, but Bob's A and C are both identical to Abe's C.
Clear as mud?
*****
Maxx, I have to ask whether you are my friend Kun Xin from Singapore. I think not, but there was at least the hint that I might know you, and he's the only person who comes to mind whom I know to be a gamer somewhere in the far east. (It occurs to me as I type this that I also have a lost brother-in-law from Tai Pei, whom I know as Peter, but I have no reason to connect you to him other than the language barrier. If I know anyone else in the Asian area, I am not cognizant of it.)
...the questions could be answered part by part and set to lowest priority which means answered last if you want to get to everyone else on the board first.
Well, that's thoughtful of you, but it doesn't work for me. If I don't stick to my methods I don't get things done, and if I don't answer your post in its entirety when you post it I will never return to it.
If the AB original does not send himself to the past but only a copy of himself plus the notion that he is only a copy, time could also stabilize in just one jump.
Let me make sure I understand this with one clarification: The AB original is sending a copy of himself back in time from point B. That means the AB original never travels in time at all, and really is not who we mean by the original time traveler--the copy is the original time traveler. That established, nothing else matters. The fact that he is a copy is irrelevant; he is the original time traveler, and for time to stabilize the original version of himself in the CD timeline must in turn copy himself and send the copy to the past just like the original version of the traveler did in the AB timeline, and the copy must not know anything that the original copy did not know (like that there was a copy sent to the past exactly like him in a previous timeline). If the copy knows something else, we have to replay an EF timeline to get a stable history.
If the copies truly are indistinguishable from the original (no copy deterioration) then you've got an N-jump based on the CD history as the stable form. It's a rather extreme and improbable way to do it, but it could be done.
The time machine that does this could prevent infinity loop as long as the copy machine and time machine is not destroyed during point D.
This isn't making sense to me. As I have said before, nothing depends on the mechanisms used for traveling to the past; what matters is the nature of time itself.
I feel like I'm saying that if you are in a car traveling five hundred miles an hour you inherently have inertia and if the car abruptly stops you will continue forward except to the degree that you are restrained by belts or airbags or other impediments, and you are answering me by saying yes, but what if you are in a plane instead? If you are traveling at five hundred miles an hour and whatever is moving you abruptly stops, inertia causes you to tend to continue forward.
If you travel to the past, you end the history that brought you to the point of departure, undo everything that happened between it and the point of arrival, and begin a new history at the point of arrival; if when you reach the time of the point of departure the exact same person who is the exact same age does not for the exact same reason make the exact same trip at the exact same moment to the exact same moment, then you cease ever to have existed and are replaced by whoever it is that lived in your place in this history; and if he does not make that trip, then he ceases ever to have existed and is replaced by you, at that moment in original unaltered time in which no one has yet arrived from the future and you have no knowledge of anything that lies in any future.
It will stabilize if the message are put to a similar particles that will travel to the past and not the rock that have travel from the future. The message must contain the position of similar particles that have to be implanted with that exact same message before going to the past.
Yes--which is exactly the same thing as saying that they don't have to be the same particles as long as they have been put into the same state.
If the time machine works like a screen wrap, the time traveler would skip point D which means that the time traveler does not arrive at that point but just skips it.
If the travel to the future could go to a future that have not been written, would this force the point D to stabilize (by making the existence of a similar twin that is send back to the past) or something?
First, all metaphors used to illustrate the subject are limited. The spreadsheet illustration, the tape recorder concept, an the screen wrap idea are all metaphors that illustrate aspects of how replacement theory works, but which will fail under enough scrutiny.
Second, I think you do not know how screen wrap works. (I think, therefore, that you are probably not Kun Xin, because he's got some solid programming skills and probably does know how screen wrap works.) There is a specific number of pixels left-to-right on the screen, and a specific number of rows top-to-bottom. I used to know both numbers for a Commodore 64, but they're not the same for a PC or a CRT or an HDTV, and the specific numbers are irrelevant. We'll say that there are 1000 pixels across, and that they are numbered 0 to 999.
Whenever an object is traveling from left to right or right to left on the screen, it moves by adding or subtracting numbers to its position, usually one digit at a time, controlled by a clock function which gives it apparent velocity. Each time it moves, the calculation is done to get the new position number, and then a check is made: is -1<x<1000? (Hmmm--it occurs to me that I don't know whether those HTML symbol codes will work and/or whether they are necessary. What I mean is is -1<x<1000.) If so, then that becomes the horizontal position on the screen. If x<0, then the system says x=x+1000, and runs the comparison again; if x>999, then it says x=x-1000 and runs the comparison again. Thus if we're at 999+1=1000, x>999 so X=1000-1000=0, and the position jumps to 0; and conversely if we're at 0-1=-1, X<0 so X=-1+1000=999, and our position jumps to 1000.
Now you're suggesting that we're going to jump to a point beyond the edge of the screen and so miss the screen wrap function; but we don't. Let's suppose that we're at 500, pretty much the center of the screen, and we add +10000. That puts us at 10500--but 10500>999, so X=10500-1000=9500; and 9500>999, so 9500-1000=8500, and so on until we get back to 500.
Now, it would not work that way with time travel--if you were in the middle of a one thousand year anomaly and you jumped a thousand years forward you would not wind up in the same spot. But this much of the analogy holds: you can't escape by jumping past the edge, because to get past the edge you have to cross the edge, and once you reach the edge you are impacted by the edge, and whatever happens at the edge happens to you when you try to cross the edge.
You're trying to run to Mars by starting out in that direction and going around the earth enough times to cover the distance; but the Pacific Ocean will probably stop you anyway.
This option would make any change that may affect the time traveler in the future will affect the time traveler that instant. This would also change the memories of the time traveler instantly if the time traveler meets with himself.
I gave a lot of thought to that, and found it unworkable as a time travel theory. I don't have a mechanism for that to happen. The mechanism I have says that the changes must propagate through the causal chains, but although they can do so "instantly" they have to be experienced sequentially at the speed of time.
The problem your notion creates appears in the infinity loop, and more so in the sawtooth snap. Let's use a simple grandfather paradox.
I travel to Mississippi around 1900. I know where my grandparents lived; they were next door neighbors. I'll kill them both to be certain. Now my father will never be born. If my father is never born, I am never born either. (My paternity is not at issue here.) If I am never born, I cannot travel to the past, and cannot kill my grandparents.
By your resolution, the moment I kill either of my grandparents, I cease ever to have existed and at that instant I cease to be--I must simply vanish; but then, at that instant, too, the affected grandparent must be both dead and alive--dead because I killed him, and if I did not kill him then I did not vanish; alive because I vanished before I killed him, because I never existed to make the trip to the past so I never arrived in the past. Thus the history of the world ends in 1900 because I arrived from 2010 and destroyed it; but if the history of the world ended in 1900, I never left from 2010 to destroy history in 1900, and so the world's history was not destroyed, and everything is as it was, except that if it is as it was it never was because I destroyed it.
The problem is, to make any sense of all this we must allow that 2010 happened, and therefore that it happens. It is plausible to say that the "first time" history reached 2010 I was alive and traveled to the past and killed my grandparents, but the "second time" history reached 2010 I had never been born and so could not leave for the past to kill my grandparents, and therefore I never arrived in the past and never killed my grandparents. But if you make the effects of my actions instantly impact me in the present history of the universe, then that history collapses because as soon as I have undone my own existence I have undone my ability to have done that, but that inherently implies that I have failed to come from the future, and that inherently implies that there is a future from which I failed to come.
I know, it's weird; but the instant change has to work through the causal chain, and so even though I am "instantly" undone, that won't affect me until the cause gets through the chain and reaches me, and that's in an altered history.
This option does not necessarily mean that the future that the time traveler came does not change, it only means that it will be change after it is rewritten in the present. If the time traveler goes to the future with the same method, the time traveler with meet with the unchanged future. If the time traveler vanishes then come back in the future world that will continue forward without the time traveler, the time traveler will go into the future that is changed by him. This is what you actually imply with your replacement theory unless I am misunderstanding something.
I'm persuaded that what you're describing requires some form of multiple dimension theory. If a time traveler under replacement theory changes the past and then travels to the future using any method, he arrives in that future which arises from his altered past. Although a lot of what happens in
Back to the Future Part II is bogus, Doc is right when he says that they can't prevent Bif from changing the world by going to the future because they'll arrive in the future that arises from the world Bif already created. Once the change is made, the only future ahead from that point is the one based on the change.
Your infinity loop actually depend on the existence of this dimension as it preserves the point of departure of time travel. If this dimension does not exist, the state of change could not happen to the time in the first place and there would only exist one final time line in which all things are fixed.
That's Sergei Koshin's argument, and I still disagree. The spreadsheet illustration does a pretty good job on this, as it shows how the change to the future can be instantaneous and still have to travel through the causal chain.
If the point of departure history is affected instantly by the change done by the time traveler, would this make meeting self in the past (if future self have not met any future selves before) changes the memory of future self instantly?
Yes and no.
It's going to be tough to clarify, but try to follow me.
Abe 1 is born in 1950 the AB history, and travels back to point C, 1950, the moment of his birth; thus Abe 2 is born in the CD history. Abe 1 never met his older self, but Abe 2 does--he meets Abe 1, who apparently takes enough of an interest in him to talk to him about something. This changes Abe 2, so that at point D when Abe 2 makes the same trip he is a different person, and so he arrives at point E, and he meets Abe 3. We'll keep it simple: nothing Abe 2 does is different enough from what Abe 1 did to make Abe 3 different from Abe 2 in any way, so Abe 3 will make the same trip as Abe 2, and the EF timeline becomes the stable history.
Now the question is whether at the instant Abe 1 meets Abe 2, Abe's memories are immediately changed so that at that moment he meets Abe 2 "his" memories are instantly changed to include having met his older self. The metaphysical answer is "yes", that at the instant Abe 1 meets Abe 2 in, say, 1960, Abe 2's memories of that moment are changed so that as he meets Abe 3 in 1960 in the EF timeline Abe 2 remembers having met Abe 1 in 1960 in the CD timeline. The change is instant, and instantly propagates forward through all future versions of Abe who have that experience.
The practical answer is "No, Abe 1's memories never change; rather Abe 1 simply ceases ever to have existed once point D is reached, and thereafter Abe 2 has become the only Abe to travel to the past, up until Abe 3 does so, undoing the existence of Abe 2; but since Abe 3 does exactly what Abe 2 does, then Abe 4 is indistinguishable from Abe 3, and for all purposes is Abe 3, and the EF timeline stabilizes. Everyone alive after point F remembers all the events of the EF timeline; Abe in particular remembers passing through it once as a child growing up and again as an adult having traveled back, and he remembers meeting himself both times, once as the younger meeting the older, and once as the older meeting the younger.
The stability of the EF timeline depends on the assumption that whatever the older Abe does in meeting the younger Abe, the younger Abe will also do when he in turn is the older Abe.
If the point of departure history is not affected instantly but must wait for the time traveler to reach it, then why is the time for the person who send the time traveler back to the past just stops at that point and do not continue forward?
I think the last illustration shows this. The change is instant and propagated through the causal chain. As long as we move through time we move with the change, but if we jump ahead we find the change already there.
If the time travel is like a "screen wrap", what is preventing the time traveler to deactivate the time machine after arriving in the past so that the "screen wrap" is gone thus continuing the time forward?
Again, because it has nothing to do with the time machine and everything to do with the nature of time. It doesn't matter if he traveled to the past by a machine or by force of will (e.g.,
Somewhere in Time), or by unexplained magic (e.g.,
It's a Wonderful Life. What matters is that time itself must be self-correcting based on the preservation of causal chains, or causality becomes meaningless and the pot boils because it's time for the pot to boil, the fire having nothing whatever to do with it.
Again, "screen wrap" is a metaphor, not an explanation.
Can the time traveler just take the his own original causality from the future and add it to the past so that whatever he does would not cause an infinity loop?
This question has no meaning to me.
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If C2 is before A1, and you successfully prevent yourself from leaving from A1 for B1, that's not a problem in itself; however, you then will have prevented yourself from leaving from B2, thus preventing your arrival at C2, and making it impossible for you to prevent yourself from leaving from A1, making the second anomaly an infinity loop.
If I freeze past self at point A1 then defrost it at point B1 then let that self to continue to leave at point B2, would that be an infinity loop?
The effects of that are much too uncertain. The problem here is that the self who departs from B1 had the memories of living from A1 to B1, and if you remove those memories someone else is making that trip--and that means that you are going to be replaced by that other person, and there is a real danger that you will never have made the trip in which you changed your younger self.
But exactly what would happen is almost anybody's guess. Put another way, there is insufficient information in this example to give any kind of answer, and if you provided sufficient information you would have to be creating a very detailed story whose facts would not apply to any other story.
Why does the time still continue onwards from point A1 even if I prevent myself from leaving thus creating an unstable future after the point of departure?
You're confused. A1 is the history of the world in which no one arrives from B1. If you prevent your prior self from departing from D1 he will never arrive at C1, and we know that the history of the world in which he does not arrive at C1 is the AB history. It is one of those extremely complicated anomalies I mentioned to John at the beginning of this post, because now his AB history is part of your CD history (and complicating it, when his history reverts from point D1 to point A1 you lose all memory of having lived from point C1 to point D1 and are passing through that time period for the first time--you can't make decisions based on what happened in the C1D1 history that now never happened for you). You have probably gotten yourself trapped in his infinity loop, but you'll never know it.
If this is the same time machine (that can send the time traveler to the past) that will filter unstable future state, would this prevent future from going onwards?
I'm hoping this is the last time I have to say this: A TIME MACHINE CANNOT PREVENT AN UNSTABLE HISTORY BECAUSE IT HAS NOTHING TO DO WITH THE WAY YOU TRAVEL TO THE PAST, BUT THE FACT THAT YOU DID. THE STABILITY OR INSTABILITY IS DUE TO THE NATURE OF TIME ITSELF.
It's like asking whether it makes a difference whether the wood was reduced to chips by a beaver or a power chipper or a magic spell. The state of the wood has nothing to do with how it got that way. The state of time has nothing to do with the tools used to bend it; it has to do with how it reacts to being bent.
It could exist if somehow at point E to B2 there exist someone outside the universe to fix the infinity loop.
Ah, this is a completely separate question. Multiverser does allow that there can be persons (in the broadest sense) from other universes or from outside time entirely who can enter an anomaly and repair it. However, to do so they have to work within the rules needed to create a stable history, and once they do we have an N-jump termination in which the final stable history is the only history of the universe known to anyone within it.
Would that mean that if the time traveler made that trip, he would be in limbo until an outside force fixes it so that in the end the time traveler would finally pass point B2 to point F?
No, it would mean that if a time traveler made that trip he would cease ever to have existed and be replaced by the version of himself who comes from the next history, which would repeat like this until eventually a stable history was created, at which point the time traveler in the final leg of the N-jump, the one departing from the middle of the stable history of the anomaly, would travel beyond the end and arrive in the future that was always his future from the only past that has ever existed in this universe, all the others having ceased ever to have existed along with everyone who ever lived in any of them.
The issues related to the "nature of time" core concepts and what type of time machine you use to model the replacement theory is the remaining issues that still confuses me a bit. This is because the time machine you use to go to the past and the future works differently. For the time travel to the future, the time for the others continue forward but for the time travel to the past, the time for the others are frozen from continuing onwards and must wait for the confirmation of travel to continue onwards.
Not at all.
It has nothing whatsoever to do with the time machine. You can use the time machine from Wells, or one of Hawking's temporally unstable wormholes, or Hermoine Granger's time turner, or Richard Collier's mental conditioning. If you travel to the past, the "tape" that is all of history rewinds to the point at which you arrive; if you travel to the future, the "tape" that is all of history fast forwards to the point at which you arrive. If it goes forward, everyone who is in it experiences at a normal temporal speed everything that they do in your absence while you hop over them all and rejoin them at that point at which they have come to the future you chose. If it goes backward, everyone reverts to that state at which they were at the point in the past you chose.
There is a sense in which all of history exists from beginning to end, and you can travel to any point in it; there is a sense in which you cause that point to become "now", to be the moment in time in which changes are happening; there is a sense in which those changes are instantly propagated through time to the end of time, and a sense in which they will be experienced and discovered moment by moment by those who live them.
There is a sense in which the future is "not yet" formed, in that it will be formed by whatever we do in the present; there is a sense in which it is "already" formed in that whatever we are going to do we have already done. When we travel to the future, we travel to the future we have created based on our actions in the present, including our departure for the future. When we travel to the past, the past also is "already" formed, but we change some of those actions in the past, and instantly the entire future changes, "already" having the new form; but if we err in our changes in the past, we can make the future formless, such that it does not exist in any form but gets caught in a correction cycle it cannot escape.
This raises another question on how does the time knows when to continue onwards even if both of them are exactly the same because as proven by infinity loop you would not know that you are in one or not so how does the time (or time machine) know the states are stable?
What is preventing the time to continue looping even if it achieves a stable state?
This one seems so obvious to me that it always confuses me when people don't get it.
What prevents history from continuing is that there is no fixed past on which to base the next moment.
Once there is a single fixed past on which to base the next moment, the next moment happens.
Why is that not simple?
--M. J. Young
