• Walter Pound
    I read a summary of it, but I haven't read the article yet. I know that Prof. Shoemaker is trying to defend the possibility that time could still pass and nothing changes. It looked like that was what you were arguing, right?
  • Metaphysician Undercover

    Yes, that's what I was arguing. It seems quite clear that it is a possibility. All you have to do is assume that there is a limit to the shortest time period required for change to occur, then conceive of an even shorter time period. In other words, even the smallest possible change requires a quantity of time, and we can always conceive of a shorter period of time. For example, if change requires a Planck length of time, we can still conceive of a time period of less than a Planck length. In that shorter time period no change would occur.

    Looks like you have to pay to read that article.
  • Terrapin Station

    If you're requiring soundness you had no argument either. Because it's false that time is anything but change/motion.
  • Terrapin Station

    I'm familiar with the Shoemaker paper. When the freezes coincide, no time passes anywhere until the next thaw. The only sense in which time passes when one freeze (but not all) occur is from the perspective of one of the zones in which a freeze does not occur. Time does not pass in the zone where the freeze occurred.
  • Metaphysician Undercover

    I know that's how you feel, you've already made that quite clear. However, with no intent to hurt your feelings, I must tell you that your feelings are quite irrelevant in this matter. So you might just pull your heart off your sleeve and discuss the issue rationally. This is not the place for special pleading, you've produced no argument for your assertion. I produced an argument to back up my claim and you rejected it on the basis that you feel it is false.
  • Terrapin Station

    Producing an incoherent argument is worthless.

    The problem is that I couldn't care less if you don't realize that time is the same thing as change/motion. All it takes is simple observation re what we're doing--functionally, that is--whenever we're referring to or utilizing time in any manner, combined with the complete lack of evidence or coherent argument that time could be anything else. But there's no reason that I'd particularly care if you don't realize this. It's not my problem that you'd have false or incoherent beliefs.
  • Metaphysician Undercover

    You saw what NoAxioms wrote, we don't use "time" and "change" in similar ways. you're assertions are completely wrong.
  • Terrapin Station
    You saw what NoAxioms wrote, we don't use "time" and "change" in similar ways. you're assertions are completely wrong.Metaphysician Undercover

    A la you're thinking that I'm saying something about conventional language usage?
  • Metaphysician Undercover

    I don't know what you're saying. It appears nonsensical according to conventional language use, and the philosophy I've studied. Yet you keep asserting it over and over again as if it's meaningful, without backing up this claim with any sort of argument od explanation.

    Time is not change, it's a parameter of measurement of change. So your claim that time is change is just like your nonsensical claim that size is an object. I really cannot see how it makes sense to you.
  • bill harris
    Although GRT indeed gives the possibility of Time-travel, the fundamental metric of de Sitter indicates that there is far too little energy in our own particular universe to accomplish this.

    Moreover, because most all of your equations in cosmology are not arrow-of time designated, the equations therein are reversible: ie not only Einstein, but also The Schrodinger and back to laPlace.

    What also seems evident is that the process of Emergence itself gives the arrow of time that's not present on a lower level.
  • SophistiCat
    I think you are mixing two unrelated issues. Time travel is not the same as reversing the arrow of time: as you correctly point out, fundamental physics is time-reversible, so from that point of view all that's needed to go backwards in time is just a sign change in the equations. But empirically such reversal would be indistinguishable from the "normal" chronology: you wouldn't suddenly be able to remember the future. - unlike the case of the "real" time travel.
  • Tomseltje
    Sounds to me like you traveled about a year into the future, just like we all do. Travel into the future seems effortless. It's not doing it that's the trick.noAxioms

    You misunderstood, the time difference with the traveler and the time passed on earth is only 1 second, though to travel 1 second into the future compared to the rest on earth took a year. When we talk about time travel we usually means creating a difference in experienced passing of time compared to the ones experiencing the regular pace of time on earth.

    Assuming time travel is to the past, as is typically assumed, it is impossible, period. A-theory has nothing to do with that.noAxioms

    Maybe a typical assumption, but since there was no indication that this was intended, it could just as well mean time travel to the future. Theoretically we can even travel to the past, our scientific models allow for that, it just requires some practically impossible implementations at the moment.

    High speed isn't required to do it.noAxioms

    high speed is just one of the options, being subjected to a different amount of gravity also works, hence strictly spoken your head ages quicker than your feet since your head is subjected to less gravity than your feet on earth when standing up straight.
    The higher your speed, the slower time goes for you, if travel at the speed of light, time stands still. The more gravity the slower time goes for you as well.
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