The Grandfather Paradox

Discussion in 'Physics & Math' started by Nogard, Oct 24, 2009.

  1. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Really?
    I'm not the one making contradictory statements.

    For something to be true it must be real. Actual.

    Maybe that helps you.

    Correct you didn't say they are true. You did however say "not wrong", which usually equates to "right".
    And again you are incorrect: I can say they're wrong if you have no evidence to support the original contention. I can say it's all nonsense, I can say it's made of cheese: because there's no evidence at all to back it up.
     
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  3. Nogard Registered Senior Member

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    No you assumed.

    I already edited my post and said it was a misunderstanding.

    "Took me while but I think I figured out the problem. We both think that we are claiming things when in fact everything is neither right or wrong . I retract my statement calling you dense. It was actually a misunderstanding. But I was almost positive you claimed to know mine were wrong?"
     
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  5. Nogard Registered Senior Member

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    New!

    You believe you are right, and I believe I'm right. We both don't know we are right.

    But if you want to know you are right you have to have evidence to prove you are right otherwise you believe you are right.


    This reply was worded in a weird way but you'll still be able to understand were I'm coming from.
     
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  7. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Ah so "not wrong" means... what?
    Not provably wrong?
     
  8. Nogard Registered Senior Member

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    I didn't really think about this ^^, but yes.
     
  9. AlphaNumeric Fully ionized Moderator

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    Doesn't work like that. You can't prove that every time you leave a room it fills with custard instantly and then magically disappears when you reenter, leaving no trace it was ever there.

    You can't disprove that but I would imagine you wouldn't put much faith in that postulation. You discount a great many unfalsifiable things purely on the grounds of common sense and rationality but that doesn't mean that something which you might find logically acceptable is certain to be true.
     
  10. John Connellan Valued Senior Member

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    And that rationality is a function of experience and what fits into our theories of these experiences (i.e. science)
     
  11. Nogard Registered Senior Member

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    Your kind of late. It was all a misunderstanding. Read all of the posts in this thread and you'll understand what me and "Dywyddyr" meant. Start at the second page and read our posts.
     
  12. kurros Registered Senior Member

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    793
    This is why we believe rather seriously in that thing they call "causality". It is pretty hard to imagine that nature allows this crazy stuff to happen. Of course we throw out physical principles now and again so who knows...
     
  13. theyoung Registered Member

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    Grandfather paradox?

    I don't recall reading that this has to do with killing yourself, rather, going back and killing your grandfather or father, thus you would not exist and could not have gone back in time. Question, why would time be a ray or a line. Time couldn't be linear. Space is not linear and time and space are one entity. Like dialing a coodinates on your GPS. Time and space are just like that.
     
  14. RJBeery Natural Philosopher Valued Senior Member

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    Presuming that a person could travel backwards in time, and since I reject the many-worlds hypothesis (which I suppose is analogous to your "ray" scenario), I would have to conclude that a time traveler could only take actions that "had already occurred" or in other words did not produce logical contradictions in a consistent history. If you intend to kill your grandfather you clearly shall fail due to the fact that you exist.

    I would say this no more contradicts free will than does the fact that you cannot choose TODAY what to have for breakfast YESTERDAY. Do you have free will to choose what to eat, or not? Ahh, it depends on when you are doing the choosing, and when you already know what the answer is you no longer have a choice...:m::m::m:
     
  15. Being someone who wants time travel to be possible and happen I hate to say this but I have face logic. That being that this.

    Statement
    Time travel isn't possible.
    Reason
    Say a man went back in time kill himself. This isn't possible because he would've never had the existance to do that from the future he was jumping back from.

    Sorry to reveal this butg you should know.
     
  16. theyoung Registered Member

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    Time Travel

    I think that we are missing something when it comes to time travel. We assume that our reality is the same as the rest of our universe. But, how then do we explain the fact that the gravitational waves produced by the big bang are all around us. In all directions that we look, it is there. How could it have passed us? We must never forget that time in itself is nothing and that space and time together make up the bulk of our Universe. I believe that dark matter holds our known universe in a flat plain ( at least our galaxies), and if we were to venture away from dark matter, we would find that space and time become as simply as dialing in. You don't need to move, just manipulate light in front of you and behind you. Traveling relatively faster than light.
     
  17. Dredd Dredd Registered Senior Member

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    Isn't the better approach to focus on the future, where we are going, so we do not run smack into the wall of the extinction of our species?
     
  18. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    deicider

    has been banned for trolling in physics.
     
  19. BenTheMan Dr. of Physics, Prof. of Love Valued Senior Member

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    Suppose a man travels back in time to before Homo sapiens had evolved. Or suppose a man travels back in time to a point where a specific genetic mutation hasn't occurred, or into the future when a genetic trait has died out (i.e. red hair). Isn't that a logical contradiction? What physical principle keeps this from happening?
     
  20. ScaryMonster I’m the whispered word. Valued Senior Member

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    Signaling between the entangled photons and the Einstein-Podolsky-Rosen paradox?

    "Basically, the idea is that interacting, or entangled, subatomic particles such as two photons -- the fundamental units of light -- can affect each other no matter how far apart in time or space." John Cramer

    "If the entanglement happens (and the experimental evidence, at this point, says it does), Cramer contends it implies retrocausality. Instead of cause and effect, the effect comes before the cause. The simplest, least paradoxical explanation for that, he says, is that some kind of signal or communication occurs between the two photons in reverse time." John Cramer


    I found this article from November 15, 2006.


    http://www.seattlepi.com/local/292378_timeguy15.html

    Did anyone see anything about this?
     
  21. RJBeery Natural Philosopher Valued Senior Member

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    Assuming that there is a single history and a single future (which I do) then I suppose we would say that time "behaves like a line" as the OP puts it. A man visiting a time before homo sapiens had evolved does not represent a logical contradiction. Traveling back to 1930 and killing Hitler DOES present a logical contradiction (unless there was a well orchestrated cover-up for about 15 years).

    Just as conditions must be "just right" for a standing wave to exist (for example), history must unfold in a self-consistent nature. Any series of events that would lead to an inconsistent past/future are simply not candidates for existence. To ask what physical principle is "restricting" us from changing the past is actually a backwards question. Ask yourself what physical principle is "restricting" us from changing the future. Can we visit Alpha Centauri tomorrow? Can we live forever? Can I transform into a dragon? Ahh, you say that we can change the future, but only in ways that are logically possible and consistent. Note that this is the very answer to your question as to what is available for us to change** the past.

    If true, does this restriction in itself mean that time travel cannot exist? I don't know but I like to fantasize that it does not. It certainly takes some of the fun out of the possibilities though.

    **Under this scenario, when dealing with time travel to the past using the word "change" is a misnomer because nothing will actually "change". The traveler will only experience what has "already happened" from his own personal perspective. Technically this is also true of the future - we do not change the future, we only experience the future as it is revealed to us.
     
  22. RJBeery Natural Philosopher Valued Senior Member

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    You're opening a large can of worms here, ScaryMonster. GR + QM implies retrocausality. Retrocausality leads to Block Time. Block Time scares people because of its implications for Free Will. Apparently Cramer hasn't completed his experiments yet but may do so soon. From this article:
    Note that I've discussed this apparent disconnect between QM and GR on this forum and many here refuse to even acknowledge that a problem exists... :shrug:
     
  23. BobG Registered Senior Member

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    That thread is titled QM vs SR not GR. Do you know the difference?
     

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