Echoes of Time Travelers

[Michael J Fox is Canadian]

Originally Posted by sn939

'Temporal duplication' in the conventional sense simply refers to a situation where two of the same person or object, originating from different points of time, co-exist (the two Marty's in BTTF2 and Ep 2 of the Game, young Emmett and Doc in 1931 etc.)

However, in this case, when they're talking about 'temporal duplication', they mean the Delorean was LITERALLY duplicated, such that the two cars had an existence independent of each other.

Case in point, if you consider all the Deloreans in Hill Valley on November 12th 1955...each one is dependent on its 'predecessor' for its existence. One couldn't tamper with, say, the Delorean Old Biff brought with him from 2015 without affecting the Delorean Marty and Doc brought from 1985-A, or the one buried in the Delgado Mine.

But the Delorean in the Game had an independent existence of the Delorean in BTTF3. One went to 1885, stayed in a mine for 70 years, went back to 1885 AGAIN, returned to 1985 and was destroyed. The other went to 2025, later (presumably) made a few time jumps, before going to 1931, and then returning to 1986 at the start of the game.

I'd think it follows the same rules as a clone; i've never seen a story involving clones and time travel. You go back in time and kill a clone before the cloning (or prevent it from being born) both die.

[Jennifer]

Originally Posted by sn939

'Temporal duplication' in the conventional sense simply refers to a situation where two of the same person or object, originating from different points of time, co-exist (the two Marty's in BTTF2 and Ep 2 of the Game, young Emmett and Doc in 1931 etc.)

However, in this case, when they're talking about 'temporal duplication', they mean the Delorean was LITERALLY duplicated, such that the two cars had an existence independent of each other.

Case in point, if you consider all the Deloreans in Hill Valley on November 12th 1955...each one is dependent on its 'predecessor' for its existence. One couldn't tamper with, say, the Delorean Old Biff brought with him from 2015 without affecting the Delorean Marty and Doc brought from 1985-A, or the one buried in the Delgado Mine.

But the Delorean in the Game had an independent existence of the Delorean in BTTF3. One went to 1885, stayed in a mine for 70 years, went back to 1885 AGAIN, returned to 1985 and was destroyed. The other went to 2025, later (presumably) made a few time jumps, before going to 1931, and then returning to 1986 at the start of the game.

I see what you mean now, and Michael J Fox is Canadian's clone explanation has me wondering. I wonder which DeLorean really was the original, and which was the duplicate. It's completely possible the DeLorean sent into 2025 was actually the original DeLorean, and the one sent into 1885 was the duplicate.

[Michael J Fox is Canadian]

Originally Posted by Jennifer

I see what you mean now, and Michael J Fox is Canadian's clone explanation has me wondering. I wonder which DeLorean really was the original, and which was the duplicate. It's completely possible the DeLorean sent into 2025 was actually the original DeLorean, and the one sent into 1885 was the duplicate.

Well the big question is was Doc duplicated?

We know that this doc (which ended up in 1885 with that delorean) eventually went to 2025 to retreive it, so did that delorean end up in mid air in 2025 without a driver? Unless something happened to him I don't think there was a duplicate doc. If there was he wouldnt know he was duplicated so you'd think 2025 doc would go back to 1955 for Marty (since he had the technology to fix the delorean).

Also the time circuits in part II were flashing January 1st 1885 twice on screen (once right before they go back to 1955 and once when doc flies the delorean to the school). Now granted these are the only 2 times we are seeing the time circuits after they leave 2015, no reason they couldnt flash 2025. Or you could argue that the combination of the jiggowat overload, scrambled time circuits, and spinning delorean confused it as to whether it should be going to the future or past (logically it should have to perform an internal calculation for how far it needs to travel and whether its forwards or backwards)

[Jennifer]

Originally Posted by Michael J Fox is Canadian

Well the big question is was Doc duplicated?

We know that this doc (which ended up in 1885 with that delorean) eventually went to 2025 to retreive it, so did that delorean end up in mid air in 2025 without a driver? Unless something happened to him I don't think there was a duplicate doc. If there was he wouldnt know he was duplicated so you'd think 2025 doc would go back to 1955 for Marty (since he had the technology to fix the delorean).

I was wondering this too, and it would certainly make sense that Doc would be duplicated too. All we know about the DeLorean in 2025 is that Doc found out that Griff found it and Doc stopped him right before he damaged the timestream.

The 1885 DeLorean was damaged, so the 2025 DeLorean would have to be fixed. It's possible Griff took the DeLorean from Doc in 2025 when he was fixing it, and the other Doc saw only Griff with the DeLorean and just assumed just the DeLorean was duplicated, leaving Doc stranded in 2025.

I was also wondering, with the fact that Doc was a whole different person from Double Visions on, what the new timeline would be like. At the very least, it would seem that some events would be different since Doc was completely secure with his inventing to the point where he was openly living in 1986 in that timeline, so that Doc doesn't seem like the kind that would destroy the time machine. Since the events happened differently, I wonder whether the temporal duplication occurred at all in the new timeline since all the variables would have to line up very precisely for that event to happen.

[Tornreaper]

I made a thread about Doc being duplicated. It would make a great twist for season 2. But anyways that has no relation to the Time machine not fading because if Doc didn't invent a time machine then it couldn't have been duplicated.

Anyways I kind of understand the whole objects not completely fading after the jump. But then again who's to say that they didn't just happen to have a copy of the newspaper in the new timeline? Also did the tombstone disappear on the photograph after he saved himself, or did they simply not show it? I can't remember. But there is no reason for him to take a picture of the ground. I also heard on the forums that it was also possible that Marty went after Doc regardless of seeing his tombstone.

If that is true then I can't believe that theory or how the time machine was able to return from 1931 and then Marty would fade out and be replaced by FCB Marty because he couldn't time travel in that timeline.

[sn939]

Originally Posted by Jennifer

I was wondering this too, and it would certainly make sense that Doc would be duplicated too. All we know about the DeLorean in 2025 is that Doc found out that Griff found it and Doc stopped him right before he damaged the timestream.

The 1885 DeLorean was damaged, so the 2025 DeLorean would have to be fixed. It's possible Griff took the DeLorean from Doc in 2025 when he was fixing it, and the other Doc saw only Griff with the DeLorean and just assumed just the DeLorean was duplicated, leaving Doc stranded in 2025.

I was also wondering, with the fact that Doc was a whole different person from Double Visions on, what the new timeline would be like. At the very least, it would seem that some events would be different since Doc was completely secure with his inventing to the point where he was openly living in 1986 in that timeline, so that Doc doesn't seem like the kind that would destroy the time machine. Since the events happened differently, I wonder whether the temporal duplication occurred at all in the new timeline since all the variables would have to line up very precisely for that event to happen.

If you're referring to the Doc of the final timeline, who showed up in Ep. 5, then I don't see why the temporal duplication wouldn't have happened. While Doc's life was different (he had a good relationship with his father, and ran his father's foundation), his path was essentially the same as that of the Original Doc's. He came up with the idea of flux capacitor in 1955, met Marty, invented the time machine in 1985, went on all the time travel trips we saw in the movies, INCLUDING the trip to 1955 in which the Delorean was struck by lightning, sending HIM to 1885 and the temporal duplicate Delorean to 2025.
The major difference between his path and the Original Doc's path is that the new Doc never got arrested as the speakeasy arsonist in 1931, and instead returned to 1986 for the Key to the City ceremony...this divergence is presumably what causes the Delorean used in Eps. 1-4 (which belonged to the Original Doc) to erase at the end of Ep. 5, because its timeline had been erased.

Originally Posted by Tornreaper

I made a thread about Doc being duplicated. It would make a great twist for season 2. But anyways that has no relation to the Time machine not fading because if Doc didn't invent a time machine then it couldn't have been duplicated.

Anyways I kind of understand the whole objects not completely fading after the jump. But then again who's to say that they didn't just happen to have a copy of the newspaper in the new timeline? Also did the tombstone disappear on the photograph after he saved himself, or did they simply not show it? I can't remember. But there is no reason for him to take a picture of the ground. I also heard on the forums that it was also possible that Marty went after Doc regardless of seeing his tombstone.

If that is true then I can't believe that theory or how the time machine was able to return from 1931 and then Marty would fade out and be replaced by FCB Marty because he couldn't time travel in that timeline.

I believe that one possible explanation for the tombstone paradox is that in the final 1955, Marty finds the photograph of the Clock Tower inaugration he took with Doc in 1885, realizes he was meant to go back, and then travels back in time. When he does, that Marty is erased and replaced by the version we follow in the film.

Thing with FCB Marty is that there was no way he could have time traveled, so logically he should still be there in FCB 1986.

[Tornreaper]

Originally Posted by sn939

I believe that one possible explanation for the tombstone paradox is that in the final 1955, Marty finds the photograph of the Clock Tower inaugration he took with Doc in 1885, realizes he was meant to go back, and then travels back in time. When he does, that Marty is erased and replaced by the version we follow in the film.

Thing with FCB Marty is that there was no way he could have time traveled, so logically he should still be there in FCB 1986.

VERY smart and logical explanation!

And yes. FCB Marty must exist. When talking to Marty's dad in episode 3 I think he says he expected you to be at some math contest or something. Not really sure. But that is still a plot hole/paradox IMO. If Marty never time traveled then it would be the same as if his past self was killed. He would cease to exist and be replaced by his temporal duplicate AKA FCB Marty.

[Michael J Fox is Canadian]

Originally Posted by Jennifer

I was wondering this too, and it would certainly make sense that Doc would be duplicated too. All we know about the DeLorean in 2025 is that Doc found out that Griff found it and Doc stopped him right before he damaged the timestream.

The 1885 DeLorean was damaged, so the 2025 DeLorean would have to be fixed. It's possible Griff took the DeLorean from Doc in 2025 when he was fixing it, and the other Doc saw only Griff with the DeLorean and just assumed just the DeLorean was duplicated, leaving Doc stranded in 2025.

I was also wondering, with the fact that Doc was a whole different person from Double Visions on, what the new timeline would be like. At the very least, it would seem that some events would be different since Doc was completely secure with his inventing to the point where he was openly living in 1986 in that timeline, so that Doc doesn't seem like the kind that would destroy the time machine. Since the events happened differently, I wonder whether the temporal duplication occurred at all in the new timeline since all the variables would have to line up very precisely for that event to happen.

It's a slightly different doc but he would have had to go through MOST of the time jumps the old doc did; Jules and Verne still exist so he'd have gone through the same path up to and including getting stuck in 1885. Now one key time jump which changed is that this doc eventually returned to 1985 to live (and has stayed there the last six months) whereas the old doc has been gone for six months.

It certainly is possible for another doc to have been stranded in 2025. Though how would our doc know about the duplication? He did indicate they were considering sending Verne to college in the 2020's so he and Clara have likely been there.

[Tornreaper]

Yeah in the final timeline Doc obviously got struck by lightning.

Also I asked this before but never got a really answer. If a paradox does happen in the BTTF universe what will the end result be? Will the universe actually explode? Have you ever considered paradoxes did happen in BTTF but we never noticed it?

[sn939]

Originally Posted by Tornreaper

Yeah in the final timeline Doc obviously got struck by lightning.

Also I asked this before but never got a really answer. If a paradox does happen in the BTTF universe what will the end result be? Will the universe actually explode? Have you ever considered paradoxes did happen in BTTF but we never noticed it?

Well, in the strictest sense, BTTF2 and 3 are LOADED with paradoxes. So the answer to your question is-nothing happens. Well, nothing catastrophic anyway.

Take the whole 1985-A/Hell Valley timeline for instance. Its one BIG paradox, on so many levels-

1. By giving himself the Almanac and making himself rich, Biff destroys his younger self's motivation to steal the Almanac and go back in time in the first place (a common problem to all intentional attempts to change the past).

2. Because alternate Biff gets Doc committed, the time machine is never constructed. If the time machine never exists, then its impossible for Biff to go back and give himself the Almanac.

3. By preventing Marty and Doc from becoming friends, by sending Marty to a boarding school, Biff has prevented them from making the trip to 2015, which was how he was meant to steal the Almanac and Delorean (though this point is pretty academic, considering that the time machine itself wasn't invented).

4. In the new timeline, Biff is apparently shot dead by Lorraine in 1996, so he couldn't be alive in 2015 to become 'Old Biff'...

So there are no less than FOUR paradoxes associated with the Hell Valley timeline! And yet, NOTHING happens to the universe...

The solution to these paradoxes, though Bob Gale has never stated them outright, is that when the time traveler alters the timeline so drastically as to prevent his own existence, or the time jump from ever happening, the time traveler will be erased from existence...but the event which caused the divergence will be preserved as a necessary part of the new timeline. So, Old Biff, by giving himself the Almanac, has logically created a major paradox, and he is erased from existence when he returns to 2015, but we still see him in 1955 giving himself the Almanac later in the film. Some people call this the 'echo theory' (the title of this thread in fact!)...I simply call it a case of the time traveler erasing the timeline he came from, and thus erasing himself.

[Tornreaper]

Originally Posted by sn939

Well, in the strictest sense, BTTF2 and 3 are LOADED with paradoxes. So the answer to your question is-nothing happens. Well, nothing catastrophic anyway.

Take the whole 1985-A/Hell Valley timeline for instance. Its one BIG paradox, on so many levels-

1. By giving himself the Almanac and making himself rich, Biff destroys his younger self's motivation to steal the Almanac and go back in time in the first place (a common problem to all intentional attempts to change the past).

2. Because alternate Biff gets Doc committed, the time machine is never constructed. If the time machine never exists, then its impossible for Biff to go back and give himself the Almanac.

3. By preventing Marty and Doc from becoming friends, by sending Marty to a boarding school, Biff has prevented them from making the trip to 2015, which was how he was meant to steal the Almanac and Delorean (though this point is pretty academic, considering that the time machine itself wasn't invented).

4. In the new timeline, Biff is apparently shot dead by Lorraine in 1996, so he couldn't be alive in 2015 to become 'Old Biff'...

So there are no less than FOUR paradoxes associated with the Hell Valley timeline! And yet, NOTHING happens to the universe...

The solution to these paradoxes, though Bob Gale has never stated them outright, is that when the time traveler alters the timeline so drastically as to prevent his own existence, or the time jump from ever happening, the time traveler will be erased from existence...but the event which caused the divergence will be preserved as a necessary part of the new timeline. So, Old Biff, by giving himself the Almanac, has logically created a major paradox, and he is erased from existence when he returns to 2015, but we still see him in 1955 giving himself the Almanac later in the film. Some people call this the 'echo theory' (the title of this thread in fact!)...I simply call it a case of the time traveler erasing the timeline he came from, and thus erasing himself.

I don't really buy the echo theory. But I do have to admit it's true in BTTF. This pretty much solves every paradox. However I don't think that solves why Marty faded away. If the echo theory does exist then all that means is even though they get erased from existence or stop them from time traveling then their actions still occurred and they still existed for a short period of time. That doesn't mean that they can freely time travel.

I stand by my statement. He should have faded. I accept that a paradox didn't happen because of the echo theory though. I think since the critical junction point was the expo he should of been fine as soon as he jumped to 1986 and then he and the time machine should have faded.

[sn939]

Originally Posted by Tornreaper

I don't really buy the echo theory. But I do have to admit it's true in BTTF. This pretty much solves every paradox. However I don't think that solves why Marty faded away. If the echo theory does exist then all that means is even though they get erased from existence or stop them from time traveling then their actions still occurred and they still existed for a short period of time. That doesn't mean that they can freely time travel.

I stand by my statement. He should have faded. I accept that a paradox didn't happen because of the echo theory though. I think since the critical junction point was the expo he should of been fine as soon as he jumped to 1986 and then he and the time machine should have faded.

That's why I don't call it the 'echo theory' because I don't believe the time traveler's from erased timelines are mere 'echoes'. They are living, breathing entities with as much free will as any other individual.

Case in point...Old Biff in 1955 wasn't just an 'echo', even if his timeline was erased. After giving the Almanac to his younger self, he was free to do anything he wanted, as long as he didn't return to 2015 (or pretty much any point in time after 1996, the year he was shot). He could have lived out his life in the past, or could have traveled back and settled down in the 19th century...he could have done ANYTHING he wanted before the date when his alternate self was shot dead. He had complete free will.

Now, granted, Old Biff's case is somewhat clear cut, in that his alternate self is supposed to be dead, so he clearly erased his existence. But Marty and Doc's case is far different...because their alternate selves were clearly alive in all the alternate timelines they visit; but simply didn't time travel. Logically, that should invalidate the existence of the time traveling versions...but somehow that doesn't really happen.

[Michael J Fox is Canadian]

Originally Posted by Tornreaper

I don't really buy the echo theory. But I do have to admit it's true in BTTF. This pretty much solves every paradox. However I don't think that solves why Marty faded away. If the echo theory does exist then all that means is even though they get erased from existence or stop them from time traveling then their actions still occurred and they still existed for a short period of time. That doesn't mean that they can freely time travel.

I stand by my statement. He should have faded. I accept that a paradox didn't happen because of the echo theory though. I think since the critical junction point was the expo he should of been fine as soon as he jumped to 1986 and then he and the time machine should have faded.

Which time are you talking about Marty fadint? In part I he fades because he critical junction point for his conception (the dance kiss) is in jeopardy. In episode 1/2 he starts fading at the same point his grandfather is killed. Both those times he is avoiding his own birth. He is clearly still born in the FCB timeline.

[sn939]

Originally Posted by Michael J Fox is Canadian

Which time are you talking about Marty fadint? In part I he fades because he critical junction point for his conception (the dance kiss) is in jeopardy. In episode 1/2 he starts fading at the same point his grandfather is killed. Both those times he is avoiding his own birth. He is clearly still born in the FCB timeline.

Marty's fading in Episode 2 didn't really make much sense as per the established rules in BTTF1 either.

Marty apparently starts fading AFTER his grandfather was beaten to death. Later, even when he travels back earlier in the day, to a time BEFORE his grandfather was in any perceivable danger, he continues to have fading 'spasms' which get progressively worse. But that really doesn't make sense.

As per the rules in BTTF1, the moment Arthur McFly died, Marty would simply fade from existence. Period. There is no way Marty can continue to exist in a time period where Arthur McFly is dead, because the probability of his existence if 0.

Also, when Marty goes back to a time BEFORE Arthur McFly was killed, he should be fine. Or at any rate, the fading shouldn't be AS bad, because there is now a probability that Marty could exist.

[Tornreaper]

Originally Posted by Michael J Fox is Canadian

Which time are you talking about Marty fadint? In part I he fades because he critical junction point for his conception (the dance kiss) is in jeopardy. In episode 1/2 he starts fading at the same point his grandfather is killed. Both those times he is avoiding his own birth. He is clearly still born in the FCB timeline.

Marty doesn't just fade in the movie and episode 1 and 2 because he ceased to exist. It was also because his time travel didn't exist. It should be the same circumstances with Marty as it was for Doc. He couldn't time travel in this timeline so he should be replaced by FCB Marty like Doc was replaced by FCB Doc.

Originally Posted by sn939

Marty's fading in Episode 2 didn't really make much sense as per the established rules in BTTF1 either.

Marty apparently starts fading AFTER his grandfather was beaten to death. Later, even when he travels back earlier in the day, to a time BEFORE his grandfather was in any perceivable danger, he continues to have fading 'spasms' which get progressively worse. But that really doesn't make sense.

As per the rules in BTTF1, the moment Arthur McFly died, Marty would simply fade from existence. Period. There is no way Marty can continue to exist in a time period where Arthur McFly is dead, because the probability of his existence if 0.

Also, when Marty goes back to a time BEFORE Arthur McFly was killed, he should be fine. Or at any rate, the fading shouldn't be AS bad, because there is now a probability that Marty could exist.

Maybe because he already experience the point after his Grandpa died even though he went back a few minutes later?

[Michael J Fox is Canadian]

Originally Posted by sn939

Marty's fading in Episode 2 didn't really make much sense as per the established rules in BTTF1 either.

Marty apparently starts fading AFTER his grandfather was beaten to death. Later, even when he travels back earlier in the day, to a time BEFORE his grandfather was in any perceivable danger, he continues to have fading 'spasms' which get progressively worse. But that really doesn't make sense.

As per the rules in BTTF1, the moment Arthur McFly died, Marty would simply fade from existence. Period. There is no way Marty can continue to exist in a time period where Arthur McFly is dead, because the probability of his existence if 0.

Also, when Marty goes back to a time BEFORE Arthur McFly was killed, he should be fine. Or at any rate, the fading shouldn't be AS bad, because there is now a probability that Marty could exist.

i'm kind of unclear on the timeline for those few days; Marty arrives June 13th 1931, June 14th is the day the murders happen so I'm assuming the newspaper he reads was printed june 15th? (I know Marty says in episode 1 he's going to the day before doc gets killed)
Arthur gives his deposition around 4 pm, in episode 2 Marty goes back to 4:45. The question is at what point is Artie killed? Also what time is the ending of ep1/begginning of 2? Seems artie got beat to death (doesn't make sense to me how he'd be found, Kid has an underground speakeasy, you'd think he'd dispose of the body?) Kid is obviously driving the police truck doc is in, had he killed Artie yet?

[Jennifer]

Originally Posted by sn939

Marty's fading in Episode 2 didn't really make much sense as per the established rules in BTTF1 either.

Marty apparently starts fading AFTER his grandfather was beaten to death. Later, even when he travels back earlier in the day, to a time BEFORE his grandfather was in any perceivable danger, he continues to have fading 'spasms' which get progressively worse. But that really doesn't make sense.

As per the rules in BTTF1, the moment Arthur McFly died, Marty would simply fade from existence. Period. There is no way Marty can continue to exist in a time period where Arthur McFly is dead, because the probability of his existence if 0.

Also, when Marty goes back to a time BEFORE Arthur McFly was killed, he should be fine. Or at any rate, the fading shouldn't be AS bad, because there is now a probability that Marty could exist.

Artie was beaten to death, so he didn't die instantly (the paper said he was "left for dead" which is a term that means that he wasn't dead when he was dumped there). He was alive at the start of episode 2 but bleeding to death from his injuries (Doc said that he was dumped on the courthouse steps only five minutes before the start of episode 2), so Marty's fading would certainly still make sense within the rules of the Back to the Future universe.

As for Marty's rate of fading out, you have to remember the ripple theory. The moment time was changed the ripple started catching up with Marty. Going back in time wouldn't stop the ripple, but it would slow it down (as going into the future past the point of erasure speeds it up). If you'll notice he wasn't fading as bad when he went back in time. At the beginning of episode 2, he was fading out. When he went back to the events of episode 1 he would remain solid for periods of time.

[Tornreaper]

Originally Posted by Jennifer

As for Marty's rate of fading out, you have to remember the ripple theory. The moment time was changed the ripple started catching up with Marty. Going back in time wouldn't stop the ripple

Pretty much what I was trying to say.

[sn939]

Originally Posted by Jennifer

Artie was beaten to death, so he didn't die instantly (the paper said he was "left for dead" which is a term that means that he wasn't dead when he was dumped there). He was alive at the start of episode 2 but bleeding to death from his injuries (Doc said that he was dumped on the courthouse steps only five minutes before the start of episode 2), so Marty's fading would certainly still make sense within the rules of the Back to the Future universe.

As for Marty's rate of fading out, you have to remember the ripple theory. The moment time was changed the ripple started catching up with Marty. Going back in time wouldn't stop the ripple, but it would slow it down (as going into the future past the point of erasure speeds it up). If you'll notice he wasn't fading as bad when he went back in time. At the beginning of episode 2, he was fading out. When he went back to the events of episode 1 he would remain solid for periods of time.

I agree its been a while since I've gone through the games so I agree that I may have got the details wrong, but somehow I've always considered the 'ripple effect' to be probability-based rather than time-based.

For instance, in BTTF1, every moment George and Lorraine DON'T get together, the probability of the McFly kids being born drops closer and closer to 0, hence they gradually begin to fade from the photograph. When they (nearly) don't kiss and the probability of Marty existing drops VERY close to 0, Marty starts to fade himself. Its not that the ripple effect takes a week to catch up, but rather there was a week between the divergence Marty caused in the timeline and the critical event which determined the fate of George McFly and Lorraine Baines one way or another.

But the Game seems to be showing the ripple effect as being time-based...almost like a disease of sorts which continues to follow Marty wherever and WHENever he goes. And this theory is reflected in Episode 5, when Marty and Doc are in 1931 when it transforms around them into the 'Burnt Hill Valley'. Doc somehow calculates that they have about an hour before the ripple effect catches up with them and erases them. How exactly DO you make a calculation like that? The way I see it, Marty and Doc should either have faded from existence the MOMENT Edna went back, or they should be able to exist indefinetly in the alternate 1931, depending on how the probabilities of their being born (or not) work out as off 1931.

[Jennifer]

Originally Posted by sn939

I agree its been a while since I've gone through the games so I agree that I may have got the details wrong, but somehow I've always considered the 'ripple effect' to be probability-based rather than time-based.

If the ripple effect were probability-based rather than time-based, in Back to the Future II Biff would have faded out the instant he arrived in 2015 since the probability of him existing as an old man was zero since he was killed in the 1990's.