• javi2541997
    4.9k
    I recently read an interesting article from a book of Robert Heinlein (1907-1988) called "By His Bootstraps". I think it is pretty worthy to share the main story here and debate it:

    The narrator does indeed set himself up "by his bootstraps" -- his present and future selves all interact with each other to produce the events. The paradoxical nature of this comes down to the case of a notebook that was provided to the narrator by the older man in the future. It contained a vocabulary of the language that was spoken by people in the future. The narrator learns the language and, as the book wears out over the years, copies it over into a notebook he had fetched from the present. This notebook, as it happens, is the very one he, as the older man, then provides to his other self. He is therefore the same person who both learns the knowledge from the notebook and put the knowledge into the notebook in the first place. The vocabulary as a certain list of items arranged in a certain way was thus complied by no one whatsoever. The knowledge exists in a closed temporal loop and is in an important sense uncaused or uncreated. The narrator himself notes that there is something peculiar about this.

    Robert Heinlein's 1941 story writes a philosophy thesis that time travel is impossible because time, in Immanuel Kant's terms, is only empirically real and does not exist independently among things in themselves. The narrator is then suddenly surprised to find two different versions of himself arriving from the future, with conflicting warnings and promises about what he can do. Traveling to the future, he meets an older man who repeats the promises, but whom he ends up distrusting. After some confusion, back in the present, he obtains some supplies and returns to the future to a period significantly earlier than when he would met the older man, intending to contest the future with him. Eventually, however, it turns out that he himself is the older man and his future is in fact, pace Immanuel Kant, secured.

    According to Kelley L. Ross in his main page (The Proceedings of the Friesian School, Fourth Series): Every instance of time travel generating an infinite number of alternative universes might be thought to violate Ockham's Razor, especially since the idea that an alternative universe could be generated in the first place has disturbing consequences for the metaphysics of identity. Simplicity and common sense rebel against such principles -- although serious versions of such metaphysics have been produced to deal with quantum mechanics, and multiple real universes were proposed by the philosopher David Lewis to explain possibility and necessity. But without them, time travel, that would allow for the sort of temporal loop in which the paradoxical and impossible watch of Somewhere in Time becomes possible, is itself impossible.

    Thoughts? Is it interesting right?
  • Hillary
    1.9k
    If Einstein traveled to the future to discover his own theory of relativity and went back in time again, then where did he create it?
  • javi2541997
    4.9k


    It would be still a paradox because according to Einstein there is not present neither future. Time is just relative or cyclical
  • T Clark
    13k
    Thoughts? Is it interesting right?javi2541997

    Evidence there is no time travel I find very convincing - Where is everybody? Why haven't we seen any people from the future? To me, that's more convincing than any scientific speculation. In response, I've heard arguments that there can be time travel, but only to a receiver in the past, so you can never travel further back than the earliest time machine. In that regard - I recommend what I think is the best time travel film, certainly my favorite - "Primer." Cost $7,000 to make. Feels very realistic. Watching, I said to myself - Yes, if time travel is ever invented, that's how it would happen.

    A book sounding similar to the one you referenced is "The Man Who Folded Himself" by David Gerrold. It also has someone interacting with different selves from different times and different timelines.

    Another really good book, dealing with paradoxes piled on paradoxes, is "One Day All This Will Be Yours" by Adrian Tchaikovsky. I also find this one very convincing in describing just how far time-travel paradoxes could go.

    Time travel either exists or it doesn't. If it does exist, it is a physical phenomenon, not a theory, therefore Occam's razor doesn't apply. The existence of time travel is not a metaphysical question, it's a question of fact, no matter what "disturbing consequences" it may or may not have.
  • javi2541997
    4.9k
    Another really good book, dealing with paradoxes piled on paradoxes, is "One Day All This Will Be Yours" by Adrian Tchaikovsky. I also find this one very convincing in describing just how far time-travel paradoxes could go.T Clark

    Thanks for the book recommendation! :up:

    The existence of time travel is not a metaphysical question, it's a question of fact, no matter what "disturbing consequences" it may or may not have.T Clark

    My guess is that when the article refers to “consequences” is related to multiuniversal scenarios. Because if it could be possible to manipulate how time “works”, then, it would be possible to manipulate our universe too. This would create different worlds with different (or similar…) T Clarks and Javis… well this is just my guess trying to see it as metaphysical but it is true that the opinion of Kant is more rigid:[Time] does not exist independently among things in themselves.
  • 180 Proof
    14k

    Time travel plots ["paradoxes"] do not work, however, because it makes no sense to go back in time to change an event which has already happened; rather it makes more sense to travel back in time to a specified moment at which an alternative parallel worldline branches off in which the alternative future is open ...180 Proof
    I prefer the more plausible, though equally speculative (or absurd), idea of a "viewing" rather than "traveling" to the past, particularly as imagined by Arthur C. Clarke in this co-authored novel ... https://en.m.wikipedia.org/wiki/The_Light_of_Other_Days ... and which is an older idea several other scifi luminaries have written about: https://en.m.wikipedia.org/wiki/Time_viewer
  • javi2541997
    4.9k
    idea of a "viewing" rather than "traveling" to the past, particularly as imagined by Arthur C. Clarke in this co-authored novel ...180 Proof

    Thanks for sharing it. Another interesting perspective indeed. As I see, time has always been an important topic to both philosophers and scientists to discuss about.
    We can see and debate a lot of views over the same topic!
  • Agent Smith
    9.5k
    If time travel is like the rewind function in an old VCR then causal paradoxes occur: To borrow Carl Sagan's example, a bulb will light before its switch is thrown! Perhaps we can jump and not "travel" through time like with DVDs and modern media players. :chin:
  • javi2541997
    4.9k
    Perhaps we can jump and not "travel"Agent Smith

    Interesting view. But if we "jump" through the time, what would happen? Do you think we would observe a metaphysical change in our world or just a loop of ourselves jumping infinite times?
  • Agent Smith
    9.5k
    Interesting view. But if we "jump" through the time, what would happen? Do you think we would observe a metaphysical change in our world or just a loop of ourselves jumping infinite times?javi2541997

    Hic sunt dracones!

    Sabrá Mandrake! señor/señorita!
  • javi2541997
    4.9k


    "I know that I know nothing"

    - Socrates

    :death: :flower:
  • Agent Smith
    9.5k
    he himself is the older manjavi2541997

    The (sad) clown Pagliacci! Visit Wikipedia for details.
  • Agent Smith
    9.5k
    I know that I know nothing"

    - Socrates

    :death: :flower:
    javi2541997

    We're left with mere opinion! Coherence theory of truth!?
  • Hillary
    1.9k
    Consider that wormhole between east and west London. When I look into it, I can see you on the other side. Now you take off from the east part with nearly the speed of light, taking the eastern mouth with you. You travel one year after you land again where you started. One year has passed in London. What do you see through the wormhole? On your side, London lies in the past, as your clock hasn't proceeded much, while on my side a year has passed. You ask me to crawl to your side. And who you meet on the other side? Yes, your one year younger you. So, I take off again and ask you two to meet me again via the wormhole mouth on the west part, in one year. So, after the two you's have played for a year, I return and ask you two again to crawl to the east part, where you will meet two of you. So there are four now! If you repeat this you will see a Pascal triangle distribution of you's. They have same age or differ by one year (the Pascal triangle shows the age distribution and total number of you's). Where does this go wrong?
  • javi2541997
    4.9k
    Where does this go wrong?Hillary

    I think it doesn't goes wrong. It is just another example of time paradox. You used an interesting one according to Pascal triangle and I liked it. But my guess is that we end up in the same place: time doesn't exist "outside" our existence. It is an empirical term. We cannot put different concepts of time (present, future, past, conditions, etc...) because they are all dependent on us.
  • Philosophim
    2.2k
    I believe Kant has it correct. Time is a descriptor, not an actual river. Essentially time is the relation of objects and forces in a causality state. So lets say we have states 1,2, and 3, all moving forward in causality by their numbers. If we somehow re-aranged the state of the universe back to 1, we did not travel through 2 and 3. We caused state 1 to be again, we did not travel backwards though causality.

    Multiple worlds explain potentials. But like potential and kinetic energy, kinetic is what actually happens. This doesn't mean there must be a world in which one person dropped a ball, and in another world another person did not.

    What has happened has happened. What has not happened, has not happened. There is no reversing it or going back.
  • SpaceDweller
    474

    I know theoretically it is possible to "travel" into the future, but not into the past.

    Therefore:
    Traveling to the future, he meets an older man who repeats the promises, but whom he ends up distrusting. After some confusion, back in the present, he obtains some supplies and returns to the future to a period significantly earlier than when he would met the older man, intending to contest the future with him.javi2541997

    Is not possible because going into the same point in the future is impossible because it requires first going into the past for a new journey into the (previous) future.
  • javi2541997
    4.9k


    What has happened has happened. What has not happened, has not happened. There is no reversing it or going back.

    Exactly :100: :up:



    You are right :up: I guess we should see time as pure forwarded pathway to walk through. Past is just some experiences we have lived and learned about
  • Hillary
    1.9k
    I believe Kant has it correct. Time is a descriptor, not an actual riverPhilosophim

    Kant was wrong. The flowing river is time.
  • Hillary
    1.9k
    You are right :up: I guess we should see time as pure forwarded pathway to walk throughjavi2541997

    We don't walk through time. The walking itself is time.
  • javi2541997
    4.9k
    We can explain it in different manners. But time has an impact on us. Wether we are the ones who walk through it or it is the time which does so.
    It is not the same when you are only 5 years old, or 25 or 65...
    Time makes an impact in our life
  • Hillary
    1.9k
    It is not the same when you are only 5 years old, or 25 or 65...
    Time makes an impact in our life
    javi2541997

    Yes. The walking can take long or fly by. It depends. It is said older people go to bed already when they wake up.
  • javi2541997
    4.9k


    [Just to clarify what I said previously]

    When I typed: we walk through time, I guess it sounded pretty poetic. As Virgil stated: tempus fugit. What I wanted to share is that time is very important, or at least influential, to humans when they do so artistic works. Since a paint to write a poem
  • Hillary
    1.9k


    You mean the time in which the artist lives influences his works? If I look to ancient Greek art it looks as if they experienced the world rather flat, and consisting of disconnected parts. I wonder if they would recognize realistic paintings.

    Or do you mean you don't look at the clock while creating art?
  • javi2541997
    4.9k


    No, I mean the opposite. I say that time could be a good motivation to create art. I am not referring about Ancient Greeks but all the ages. For example: a painting about an autumn afternoon because it makes you feel nostalgic
  • Hillary
    1.9k
    No, I mean the opposite. I say that time could be a good motivation to create art. I am not referring about Ancient Greeks but all the ages. For example: a painting about an autumn afternoon because it makes you feel nostalgicjavi2541997

    Ah, paintings, or art about time?
  • 180 Proof
    14k
    :up:
    We don't walk through time. The walking itself is time.Hillary
    :fire:

    The Fermi Paradox redux: Where are they – all the backtravelers (chrononauts) from the future? :chin:
  • javi2541997
    4.9k
    Ah, paintings, or art about time?Hillary

    Both.
  • javi2541997
    4.9k


    :up:

    This begins to sound like the Liar paradox, where, if a sentence is true, it's false, and, if it is false, it's true
    A very similar paradox, allowed by the possibility of the same kind of temporal loop, can become a reductio ad absurdum for time travel
  • Agent Smith
    9.5k
    The Fermi Paradox redux: Where are they – all the backtravelers (chrononauts) from the future?180 Proof

    11 April 1954!
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