Past Time Travel: What Paradox?
February 8, 2017 at 12:45 am
(This post was last modified: February 8, 2017 at 12:57 am by maestroanth.)
So I'm going to try to argue the grandfather paradox in the following manner with 2 assertions:
1. Any device that would reverse time will only be able to send the information no faster at the speed of light or causality (so in essence, the only time that will be effected would be within a light-cone spacetime interval away from the time traveling device that would gradually shrink...., so the whole Universe could not be affected)
2. YOUR TIME will not go in reverse (A common assumption, Marty Mcfly doesn't get younger when he drives the delorion back to 1955).
3. Just to be fair, let's just assume everything is pre-determined (events would resolve the same assuming without your influence)
Okay, so given assertion one, you will not be reversing some "master clock that ticks the Universe" that people I think commonly mis-thinks time as. Unless you break relativity somehow, this should be impossible at such a fundamental level that we wouldn't even be talking about "time" anymore if you are trying to change a "master clock".
Given this, you can kinda imagine a "master clock" as a conglomeration of little clocks going independent of each other even though it's more proper to think of it as separate light/causality cones. So where is the paradox of just turning one of these "little clocks" backwards huh?
To elaborate, say when you reverse time a whole light/causality cone around you (a little clock), since your time (or YOUR little clock) will not go in reverse, you'll still be ticking along a different timeline relatively speaking (thus a different past set of causes). Meaning, when you reverse time, and decide to shoot your grandfather, all you are doing is just preventing a second version of you from being born. You will not disappear like in the movies because they are simply not linked (your existence is still dependent on a previous and different set of 'causes'!).
If you still desperately want to try and create the paradox by adding the condition that you are reversing your own time too to link the two clocks, and just make a different decision, this still doesn't work because you will not have any "future memories" that will come along for the ride to see a change to compare (since your brain will be forgetting these as it progresses backwards in causality too!) Also, it means if you try to go before you are born to cause a paradox, you'll be turning into a child and then a baby, and then a zygote all the way back into the sperm/egg cell that made you....
I mean you really don't need assumption 1, but it's just to point out a misconception about time and info travel, and if you want #2 to be true it's kind of a packaged deal with #1. You're going to have separate your own personal light/causality cone out somehow so you don't just get younger yourself as you go back in time.....and since all time and causality is indeed relative, not absolute, you can use this to your advantage to virtually prevent any sort of paradox.
I don't know thinking of time like this helps my brain escape a lot of logical contradictions about past time travel. Feel free to carry my rant further or whatever!
1. Any device that would reverse time will only be able to send the information no faster at the speed of light or causality (so in essence, the only time that will be effected would be within a light-cone spacetime interval away from the time traveling device that would gradually shrink...., so the whole Universe could not be affected)
2. YOUR TIME will not go in reverse (A common assumption, Marty Mcfly doesn't get younger when he drives the delorion back to 1955).
3. Just to be fair, let's just assume everything is pre-determined (events would resolve the same assuming without your influence)
Okay, so given assertion one, you will not be reversing some "master clock that ticks the Universe" that people I think commonly mis-thinks time as. Unless you break relativity somehow, this should be impossible at such a fundamental level that we wouldn't even be talking about "time" anymore if you are trying to change a "master clock".
Given this, you can kinda imagine a "master clock" as a conglomeration of little clocks going independent of each other even though it's more proper to think of it as separate light/causality cones. So where is the paradox of just turning one of these "little clocks" backwards huh?
To elaborate, say when you reverse time a whole light/causality cone around you (a little clock), since your time (or YOUR little clock) will not go in reverse, you'll still be ticking along a different timeline relatively speaking (thus a different past set of causes). Meaning, when you reverse time, and decide to shoot your grandfather, all you are doing is just preventing a second version of you from being born. You will not disappear like in the movies because they are simply not linked (your existence is still dependent on a previous and different set of 'causes'!).
If you still desperately want to try and create the paradox by adding the condition that you are reversing your own time too to link the two clocks, and just make a different decision, this still doesn't work because you will not have any "future memories" that will come along for the ride to see a change to compare (since your brain will be forgetting these as it progresses backwards in causality too!) Also, it means if you try to go before you are born to cause a paradox, you'll be turning into a child and then a baby, and then a zygote all the way back into the sperm/egg cell that made you....
I mean you really don't need assumption 1, but it's just to point out a misconception about time and info travel, and if you want #2 to be true it's kind of a packaged deal with #1. You're going to have separate your own personal light/causality cone out somehow so you don't just get younger yourself as you go back in time.....and since all time and causality is indeed relative, not absolute, you can use this to your advantage to virtually prevent any sort of paradox.
I don't know thinking of time like this helps my brain escape a lot of logical contradictions about past time travel. Feel free to carry my rant further or whatever!
![[Image: tumblr_nvrbfbDXgM1u0bifgo1_400.jpg]](https://images.weserv.nl/?url=41.media.tumblr.com%2F973cc4438173f0121d72f6828c4110cb%2Ftumblr_nvrbfbDXgM1u0bifgo1_400.jpg)
(pester tibs via pm if you need invite) 
![[Image: tmPmhjd.jpg]](https://images.weserv.nl/?url=i.imgur.com%2FtmPmhjd.jpg)
