# Back to the Future Part II's 1985A **URL:** \ **Category:** Cafe Society\ **Created:** [January 16, 2010, 10:07am UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187 "2010-01-16T10:07:27Z")\ **Posts on this page:** 15\ **Page:** 3
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [January 18, 2010, 9:52pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/41 "2010-01-18T21:52:24Z")
> [@koufax](#): > > I wish I could go back in time and NOT open this thread. Somewhere, somewhen, you haven’t. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [January 18, 2010, 9:59pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/42 "2010-01-18T21:59:30Z")
Just a thought. What if the person in that timeline (e.g. Marty that is the son of the confident George at the end of BTTF 1) does the fading? Not very fair I admit. Matry’s problem in BTTF was that with no doppelganger to fade, HE did the fading. Would that resolve the paradoxes? ---
**Author:** ![MyFootsZZZ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/myfootszzz/32/12580_2.png) [@MyFootsZZZ](https://boards.straightdope.com/u/MyFootsZZZ)\ **Post date:** [January 18, 2010, 10:17pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/43 "2010-01-18T22:17:32Z")
None of the Butter-McFly Effect children had a chance anyway, after Marty goes back in time. It’s a movie. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [January 18, 2010, 11:03pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/44 "2010-01-18T23:03:28Z")
> [@cmyk](#): > > OTOH, you could say that what was keeping him around was a probability wave. That the chances of George and Loraine hooking up at the Dance (Rhythmic Ceremonial Ritual), became much lower than what would’ve happened if Marty didn’t interfere, but not a zero chance, so it kept Marty and the picture (and the Delorian) intact, until that actual moment crystalized. So the fading was just a cinematic way of describing the probability wave. Yay. Somebody gets it and I didn’t even have to try to explain it. I just was describing the probability wave as a superposition of states. A part you are missing is temporal inertia: timelines resist being changed. As long as there was still a chance that his parents would still get together, the timeline defaulted to Marty remaining in existence. As the probability of them getting together decreased, said inertia decreased, and “fading” is when the inertia becomes insufficient to hold the time line back. I do think you could make sense out of different events fading at different times: the events closest to the point are the least likely to happen without change, as the correction itself would have to change things. But you would think that the probability of Marty’s siblings being born was about the same as his own, being so far away from the change point. Now, if it had taken Marty so long to fix it that his parents may not have conceived his older brother–that might make more sense. ---
**Author:** ![MyFootsZZZ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/myfootszzz/32/12580_2.png) [@MyFootsZZZ](https://boards.straightdope.com/u/MyFootsZZZ)\ **Post date:** [January 18, 2010, 11:17pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/45 "2010-01-18T23:17:57Z")
> [@BigT](#): > > Yay. Somebody gets it and I didn’t even have to try to explain it. I just was describing the probability wave as a superposition of states. > > A part you are missing is temporal inertia: timelines resist being changed. As long as there was still a chance that his parents would still get together, the timeline defaulted to Marty remaining in existence. As the probability of them getting together decreased, said inertia decreased, and “fading” is when the inertia becomes insufficient to hold the time line back. > > I do think you could make sense out of different events fading at different times: the events closest to the point are the least likely to happen without change, as the correction itself would have to change things. But you would think that the probability of Marty’s siblings being born was about the same as his own, being so far away from the change point. > > Now, if it had taken Marty so long to fix it that his parents may not have conceived his older brother–that might make more sense. In the movie… but in real life, they would have to had to conceived at the same exact moment as they had before, right? Same sperm, same egg. I mean ‘Marty’ could have been a girl. To think Marty’s influence wouldn’t alter everything, (which he did apparently), including his and his sibling’s own existence… I mean, _IRL_. I know the kiss in the context of the movie symbolized that the tracks were set in place. ---
**Author:** ![MyFootsZZZ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/myfootszzz/32/12580_2.png) [@MyFootsZZZ](https://boards.straightdope.com/u/MyFootsZZZ)\ **Post date:** [January 18, 2010, 11:28pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/46 "2010-01-18T23:28:31Z")
Funny I say, “_in real life_”. You know what I mean. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [January 19, 2010, 5:49am UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/47 "2010-01-19T05:49:09Z")
I _do_ know what you mean… time travel IS possible! ---
**Author:** ![Jragon](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Post date:** [January 19, 2010, 6:03am UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/48 "2010-01-19T06:03:00Z")
> [@koufax](#): > > I wish I could go back in time and NOT open this thread. Why? This is all quite simple. You see, first you have to imagine a frictionless sphere tangent to a hypercat standing on a 2D plane and then rotate that 257 degrees to your meta-left… ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [January 19, 2010, 11:02am UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/49 "2010-01-19T11:02:15Z")
> [@Jragon](#): > > Why? This is all quite simple. > > You see, first you have to imagine a frictionless sphere tangent to a hypercat standing on a 2D plane and then rotate that 257 degrees to your meta-left… You know, I can _almost_ picture that… if I knew what a hypercat was. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [January 19, 2010, 1:20pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/50 "2010-01-19T13:20:55Z")
> [@cmyk](#): > > You know, I can _almost_ picture that… if I knew what a hypercat was. A quick Google gave me [this](http://hypercat-z.deviantart.com/art/My-Little-Hypercat-Z-142953271/). ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [January 19, 2010, 3:24pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/51 "2010-01-19T15:24:40Z")
> [@cmyk](#): > > You know, I can _almost_ picture that… if I knew what a hypercat was. Would it help if you buttered it?: [Buttered cat paradox - Wikipedia](http://en.wikipedia.org/wiki/Buttered_cat_paradox) ---
**Author:** ![Jragon](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Post date:** [January 19, 2010, 8:40pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/52 "2010-01-19T20:40:17Z")
> [@cmyk](#): > > You know, I can _almost_ picture that… if I knew what a hypercat was. It’s a cat made up of smaller dimensional cats. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [January 20, 2010, 11:14am UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/53 "2010-01-20T11:14:11Z")
And, of course, a hypercat goes up to nine dimensions. ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [January 20, 2010, 2:24pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/54 "2010-01-20T14:24:08Z")
Mine goes to eleven. ---
**Author:** ![Surbey](https://avatars.discourse-cdn.com/v4/letter/s/4491bb/32.png) [@Surbey](https://boards.straightdope.com/u/Surbey)\ **Post date:** [January 21, 2010, 8:11pm UTC](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187/55 "2010-01-21T20:11:38Z")
IMHO, people in the BttF Universe only disappear when their fate is sealed. Had Marty not caused his parents to be to kiss, he wouldn’t exist. So, since they didn’t immediately disappear, it could be said that their fate was already determined to set everything back to normal. Had they not already been destined to fix Biff’s meddling, they would have disappeared. [Previous page](https://boards.straightdope.com/t/back-to-the-future-part-iis-1985a/525187.md?page=2)