does time travel?

Time does exist, if it didn't events wouldn't happen in order, there would be no sequence to them etc. However, I believe that we as humans have not yet evolved to the stage where we can undersand it fully. It would be foolish trying to decipher it, as you will get hundreds of responces with hundreds of opinions and the arguments can go on for years because there is not much evidence to fully back any of the claims.

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Originally Posted by MorpheusSandman

I don't think you've comprehended what you've started. There have been about 3 or 4 epic threads by now with people (mostly me) trying to explain MWI to YesNo. You are in for a lot of this: :mad2: if you continue on this course.

Not really sure what you mean here. MWI says that each option of the "choice" happens in different worlds, so I'm not sure what you mean you'd have "free will within each universe, because each decision creates a new branch." Besides, that's not entirely accurate of what happens. It's more accurate that each choice diverges an intersects with an existing branch. It's not really clear if any genuinely "new" worlds are created as opposed to all worlds co-existing, diverging, and intersecting at each decoherence point.

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That is pretty clear. Any and every decision can be made in each world, but each different decision splits the universe. I agree that there is no necessary reason for a new universe being created with each decision, but that what the theory says.

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Originally Posted by PeterL

I have more problems with travel to the future than with travel into the past. There is no future; there are just possibilities. But Mr Everett has pointed out that all of the inifinty of possibilities has to come into existence. That makes the problem o travel to the future going home.

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As far as future travel goes, it is just getting there faster than one would normally get there if one stayed on the original frame of reference. Of course, it takes a lot of energy to achieve that.

Suppose many worlds were true and you went back into the past, what you would be doing is creating a new universe by splitting one of the past universes. This would avoid the grandfather paradox. But how do you know you went back to the universe you were in originally? How would you get back to your home universe?

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Originally Posted by Sweetgirl

Time does exist, if it didn't events wouldn't happen in order, there would be no sequence to them etc. However, I believe that we as humans have not yet evolved to the stage where we can undersand it fully. It would be foolish trying to decipher it, as you will get hundreds of responces with hundreds of opinions and the arguments can go on for years because there is not much evidence to fully back any of the claims.

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It is likely foolish to try deciphering time, but it is entertaining. At the moment, I look at time as a sort of sliver of the present. I don't think a "block universe" exists where time and space are all completely determined in one big block of space-time.

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Originally Posted by YesNo

As far as future travel goes, it is just getting there faster than one would normally get there if one stayed on the original frame of reference. Of course, it takes a lot of energy to achieve that.

Suppose many worlds were true and you went back into the past, what you would be doing is creating a new universe by splitting one of the past universes. This would avoid the grandfather paradox. But how do you know you went back to the universe you were in originally? How would you get back to your home universe?

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The Many Worlds Interpretation of Quantum Theory is much more likely to be true than any other way of looking at the theory. I agree with you that MWI sidesteps the grandfather paradox, but a paradox is only that, and apparent contradiction, not an actual contradiction. The answers to the other questions are in stories that I have written, so you will have to twist the arm of a publisher, if you want to read them in this branch of the multiverse.

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Originally Posted by free

I've read that time doesn't exist and that it is an illusion of our senses.

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What free probably meant-- and you aren't going to like this either-- is that time, being perceived by the senses, is only posited by consciousness.






J

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Originally Posted by PeterL

Any and every decision can be made in each world, but each different decision splits the universe.

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Right, but I'm not getting how you think that relates to free-will...

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Originally Posted by PeterL

I agree that there is no necessary reason for a new universe being created with each decision, but that what the theory says.

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No, the theory (actually interpretation) says that each world is already present in the wavefunction and something like a "decision" would be a point of "decoherence" where the already-present worlds split from each other. This isn't "creation" of new worlds, it's the "decoherence" of worlds that are already there. Think of it as a zipper: both sides of the zipper are already there, and you wouldn't say that the act of unzipping "creates" a new zipper, but that it detaches the two zipper halves that were there.

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Originally Posted by Sweetgirl

Time does exist, if it didn't events wouldn't happen in order, there would be no sequence to them etc. However, I believe that we as humans have not yet evolved to the stage where we can undersand it fully. It would be foolish trying to decipher it, as you will get hundreds of responces with hundreds of opinions and the arguments can go on for years because there is not much evidence to fully back any of the claims.

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So we should just put our hands up and call it hopeless then? What a dim and fatalistic view. Just because something is difficult or complicated does not mean we shouldn't try. Your attitude would get us exactly nowhere.

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Originally Posted by PeterL

The Many Worlds Interpretation of Quantum Theory is much likely to be true than any other way of looking at the theory. I agree with you that MWI sidesteps the grandfather paradox, but a paradox is only that, and apparent contradiction, not an actual contradiction. The answers to the other questions are in stories that I have written, so you will have to twist the arm of a publisher, if you want to read them in this branch of the multiverse.

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I think you said you had some blog posts somewhere on the topic. That might clarify your position for me.

It occurred to me that should you go into a many worlds time machine, decide to press the button, you would split the current universe into at least two universes, one where you stay in the current universe and the other where you go into a different past universe splitting it in the process. So you don't have to worry about coming back to the home universe. You never left it.

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Originally Posted by Jack of Hearts

What free probably meant-- and you aren't going to like this either-- is that time, being perceived by the senses, is only posited by consciousness.

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I doubt that time actually exists although I'm confused about the details. Here are two extreme positions:

1) Eternalism: http://en.wikipedia.org/wiki/Eternal...sophy_of_time) In this article, I liked what Karl Popper had to say.

2) Presentism: http://en.wikipedia.org/wiki/Present...sophy_of_time) In this article, there was a quote by William James that I think I could agree with.

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Originally Posted by Jack of Hearts

What free probably meant-- and you aren't going to like this either-- is that time, being perceived by the senses, is only posited by consciousness.

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I doubt that time actually exists although I'm confused about the details. Here are two extreme positions:

1) Eternalism: http://en.wikipedia.org/wiki/Eternal...sophy_of_time) In this article, I liked what Karl Popper had to say.

2) Presentism: http://en.wikipedia.org/wiki/Present...sophy_of_time) In this article, there was a quote by William James that I think I could agree with.

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Originally Posted by YesNo

I doubt that time actually exists although I'm confused about the details. Here are two extreme positions:

1) Eternalism: http://en.wikipedia.org/wiki/Eternal...sophy_of_time) In this article, I liked what Karl Popper had to say.

2) Presentism: http://en.wikipedia.org/wiki/Present...sophy_of_time) In this article, there was a quote by William James that I think I could agree with.

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time is the changes of day and night then add into it the changes in the season cold and warmth, atmosphere and there it is time. so light and temperature is time. there may something else added to it such as sound or movement. that is my interpretation :)

Yes, that's how I see it as well. It is just our experience of change. It doesn't actually exist as a real dimension.

If that is the case, I don't see how one can travel through time.

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Originally Posted by YesNo

I think you said you had some blog posts somewhere on the topic. That might clarify your position for me.

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My blog is here on Litnet. http://www.online-literature.com/forums/blog.php?4509

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It occurred to me that should you go into a many worlds time machine, decide to press the button, you would split the current universe into at least two universes, one where you stay in the current universe and the other where you go into a different past universe splitting it in the process. So you don't have to worry about coming back to the home universe. You never left it.

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You are starting to understand why there is an infinity of universes. It gets even worse when one thinks about the future.

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Originally Posted by MorpheusSandman

Right, but I'm not getting how you think that relates to free-will...

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That's simple. One can make decisions that are independent and give the appearance of being freely made; although like everything they will be determined by cause and effect, but because all possible decisions are said to be made in effect there is free will.

No, the theory (actually interpretation) says that each world is already present in the wavefunction and something like a "decision" would be a point of "decoherence" where the already-present worlds split from each other. This isn't "creation" of new worlds, it's the "decoherence" of worlds that are already there. Think of it as a zipper: both sides of the zipper are already there, and you wouldn't say that the act of unzipping "creates" a new zipper, but that it detaches the two zipper halves that were there.[/QUOTE]

Your analogy is not correct. There would be point A in which universe A exists. Then there would be decision point B where there would be decoherence B. Then ere would be time C in which there would be universe A in which decision B was not made, and there would be universe B in which decision B was made. The two universes would be complete and inaccessible from the other. While the origin of universe B is in the earlier universe A, there was a point when universe B started to exist. First there was one; then there were two.

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Originally Posted by Jack of Hearts

What free probably meant-- and you aren't going to like this either-- is that time, being perceived by the senses, is only posited by consciousness.J

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You are mistaken. Time is separation between events. If there were no time, then everything would be happening simultaneously.

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Originally Posted by PeterL

You are starting to understand why there is an infinity of universes. It gets even worse when one thinks about the future.

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Except AFAIK, infinity is strictly a mathematical concept that doesn't apply to physical reality. There's a finite amount of matter in the universe, for example; it's just a very large number.

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Originally Posted by Calidore

Except AFAIK, infinity is strictly a mathematical concept that doesn't apply to physical reality. There's a finite amount of matter in the universe, for example; it's just a very large number.

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Think what you like.

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Originally Posted by PeterL

That's simple. One can make decisions that are independent and give the appearance of being freely made; although like everything they will be determined by cause and effect, but because all possible decisions are said to be made in effect there is free will.

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This just sounds like gobbledygook to me. It vaguely sounds like you're supporting the compatibalist version of free-will that states that even if our choices are determined, because we can not know the full causes and effect beforehand our choices will still feel free to us.

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Originally Posted by PeterL

Your analogy is not correct. There would be point A in which universe A exists. Then there would be decision point B where there would be decoherence B. Then ere would be time C in which there would be universe A in which decision B was not made, and there would be universe B in which decision B was made. The two universes would be complete and inaccessible from the other. While the origin of universe B is in the earlier universe A, there was a point when universe B started to exist. First there was one; then there were two.

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This is quite wrong. The entire POINT of the wavefunction is that, mathematically, every option is contained within the formula. When we observe it, ie when two quantum states interact, we experience only one of those possibilities. So, to correct your explanation, there is point AB in which universe A and B co-exist in a single universe. There is decision point C where there is decoherence C, and, after that decoherence, we get a separated world for both A and B. Obviously there will always be before-C in which A and B are AB, but once the decision is made, A and B are mutually inaccessible. You seem to be assuming that "not making decision C" means that new-world B is created, but this is incorrect. "Not making decision C" would actually be one of the possibilities of decision C. So we can rephrase this as having point ABC in which A is making decision with option 1, B is making decision with option 2, and C is not making the decision between option 1 and 2. The act of not making that decision is still a decision, and would split the ABC point into World A, World B, and World C.

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Originally Posted by Calidore

Except AFAIK, infinity is strictly a mathematical concept that doesn't apply to physical reality. There's a finite amount of matter in the universe, for example; it's just a very large number.

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hi Calidore. infinity is a number. finity however is not.