Time Machine

[Ethelred]

Originally posted by DinoDoc

Whats to stop me from burning the Certificate. Magic? Not getting to the past will work but that isn't compatible with an assumption of a time machine.

If you burned the certificate, why would you go back into the past to burn the certificate?

Because YOU remember the certificate.

There seems to be difficulty here for some of POINT OF VIEW. The whole idea of time travel REQUIRES a muliverse of branching time.

You decide some certificate must be burned.

You happen to have a Handy Dandy Acme Time Machine.

You go go back in the past.

You burn the certificate.

You go forward

You see a world in which the certificate burned. IT IS NOT THE WORLD YOU STARTED IN. You most likely weren't even born in the BRANCHED world.

The world you came from STILL EXISTS. Its just on a different track. You didn't change a thing in the world you came from. You created a whole new branch of time.

Where once there was one branch now there are two. Two of many.

[Capt Dizle]

I dunno. Deep stuff. I just wanna know why my branch has so many damn liberals sitting on it.

[Lung]

Originally posted by Ethelred


I am fairly certain that if time travel is possible then you create a new universe and there are no paradoxes in that case. How could you enter the past all otherwise as simply being there will eventually change the future in some way. Besides I was in Junior High School then. There would be two of me. One 12 years old and the other whatever it would be when I was to go back.

Safe in the knowledge that you have created a parallel universe simply by going back in time, i would visit some early humans and become a god I could teach them modern magic without fear of repercussions to my own existence

[Odin]

Originally posted by Ethelred
Absolutly

He should stomp on the proto-MOSQUITO.

Spiders keep those vile things down.

you are forgeting one thing, mosquitos are pollinators, DAM*

[carnide_]

I dont think it will be practical to build a time machine.
Check here:

http://apolyton.net/forums/showthread.php?s=&threadid=62117

[Aeson]

Can causality and time travel (in a traditional sense, "time machine" type stuff) coexist? In a causal existance, building the time machine and using it to "go back" in time would actually just be continuing on the same time path. Moving into the future as it were, but making tremendous changes to the environment during the "time travel" transition.

Consider an object at a certain position. After it has been moved, moving it back doesn't constituted going back in time. This is apparent because all the other objects which are now in new positions/states that don't coincide with the past moment (this includes the mental state of any third party observers as well). But moving everything back (including the mental states of any third party observers) would seem like going back in time, even though it is just following the natural progression of time.

Looked at in a causal light, you can recreate a moment in time, but never actually go back in time. If you are recreating a moment where there was a certificate to burn, it is no more changing the past to do so than it would be to burn a like certificate in the future.

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As for paradoxes, your existance in a time frame that you hadn't previously existed in would cause differences in the future regardless of what you did. Just the air you displace and the microbes you pick up or leave behind could very well significantly alter the progression of history. Think of the chaos theory example of an unaccounted for butterfly in a weather prediction system.

[JCG]

I'd go back and kill Marx and/or Engels, and their contemporary brethen...

Or on the other hand, I could go back and topple all the Kings and Lords that were around back then...

Same thing.

[johncmcleod]

originally posted by Aeson:
Can causality and time travel (in a traditional sense, "time machine" type stuff) coexist? In a causal existance, building the time machine and using it to "go back" in time would actually just be continuing on the same time path. Moving into the future as it were, but making tremendous changes to the environment during the "time travel" transition.

Consider an object at a certain position. After it has been moved, moving it back doesn't constituted going back in time. This is apparent because all the other objects which are now in new positions/states that don't coincide with the past moment (this includes the mental state of any third party observers as well). But moving everything back (including the mental states of any third party observers) would seem like going back in time, even though it is just following the natural progression of time.

Looked at in a causal light, you can recreate a moment in time, but never actually go back in time. If you are recreating a moment where there was a certificate to burn, it is no more changing the past to do so than it would be to burn a like certificate in the future.

--------------

As for paradoxes, your existance in a time frame that you hadn't previously existed in would cause differences in the future regardless of what you did. Just the air you displace and the microbes you pick up or leave behind could very well significantly alter the progression of history. Think of the chaos theory example of an unaccounted for butterfly in a weather prediction system.

Wow. That's what I call high level thinking. Though I don't understand that too well, I agree with you on everything. The slightest action could completely change everything. The displacement of molecules could cause different sperm (though Ethelred was the one that said that) to meet the egg, for it might have caused a the whole thing to happen a split second later. Who knows. It could completely alter evolution, for a different mutation might come out for one creature, and maybe Hitler may have never been born.

[Odin]

Originally posted by Aeson
Can causality and time travel (in a traditional sense, "time machine" type stuff) coexist? In a causal existance, building the time machine and using it to "go back" in time would actually just be continuing on the same time path. Moving into the future as it were, but making tremendous changes to the environment during the "time travel" transition.

Consider an object at a certain position. After it has been moved, moving it back doesn't constituted going back in time. This is apparent because all the other objects which are now in new positions/states that don't coincide with the past moment (this includes the mental state of any third party observers as well). But moving everything back (including the mental states of any third party observers) would seem like going back in time, even though it is just following the natural progression of time.

Looked at in a causal light, you can recreate a moment in time, but never actually go back in time. If you are recreating a moment where there was a certificate to burn, it is no more changing the past to do so than it would be to burn a like certificate in the future.

--------------

As for paradoxes, your existance in a time frame that you hadn't previously existed in would cause differences in the future regardless of what you did. Just the air you displace and the microbes you pick up or leave behind could very well significantly alter the progression of history. Think of the chaos theory example of an unaccounted for butterfly in a weather prediction system.

Huh?

[johncmcleod]

What he is basically saying is make everything go backwards, to recreate a moment in time. I don't know when that'll be possible though. How can we change the path of the sun?