3 ms·

Somehow I get down voted for sharing this simple thought. As we participate the same reality you need to admit time travelling is a must have of a pop science m

Somehow I get down voted for sharing this simple thought. As we participate the same reality you need to admit time travelling is a must have of a pop science magazines. But this sentence makes it all nonsense - as there's no proof for time existing. Time is a useful abstraction for calculating physical models, making forecasts. As we have other useful abstractions in math or programming - it doesn't make them existing in real world. So to disagree it's enough to proof time existence or link to such proof.

coldtea 8y ago
>But this sentence makes it all nonsense - as there's no proof for time existing. First, if we're realists/utilitarian/pragmatists we don't need some fancy proof for time existing. We can see that the material world changes and we call that time. We even measure that passage with clocks. We even know (and have proven experimentally) that things going faster slow down clocks on them. So, whether time "really exists" or not is a meaningless question when we're concerned with time as we experience and know it. It's like someone shooting a bullet at you, and you are asking "yes, but does this bullet _really_ exist?". Well, it might not (e.g. we might all live in a simulation, or the nature of physical objects might be just some probability distribution of information, and not "exist" in the plain sense we understand it), but in this life as we know it, a bullet hitting you will still have the consequences we know and expect. Second, time exists in Relativity equations, so there's that. >Time is a useful abstraction for calculating physical models, making forecasts. As we have other useful abstractions in math or programming - it doesn't make them existing in real world. Doesn't matter. It's enough that we can measure it, we don't care for the "thing in itself" or if it's merely some illusion. We live in a universe where whether it's an illusion or not, it has the same effects for us (e.g. we grow old, things change state, our clock dials rotate).
- madmaniak 8y ago
  I'm glad you've bothered to answer. I don't need a fancy proof either - any proof would be enough. What we both can agree is that things or processes are happening. They don't need time for that. Constant change, constant mutation doesn't require past or future, but now only. But as I said, we - intelligent species - need a concept of time to predict how the change will proceed. What we measure in clocks depends on a clock - a sand falling down in a sand glass, a pendulum or a spring cycle and so on. After this we make a relation from this event and start to measure other events with it. Still it's just things happening, not a prove of a time existence. If you say that you experience time. Well. That's how neural network works - they are shaped by events/impulses which happened to the network and accessing this information gives you illusion of a past - but this information encoded in your brain exists now. > Doesn't matter. It's enough that we can measure it, we don't care for the "thing in itself" or if it's merely some illusion. We live in a universe where whether it's an illusion or not, it has the same effects for us (e.g. we grow old, things change state, our clock dials rotate). So we agree in a part that things change state and this is enough to imply growing old and rotating clocks. I don't agree it doesn't matter - as if the time doesn't exist, we don't need to have a pointless discussion about "travelling in time".
  - coldtea 8y ago
    >Constant change, constant mutation doesn't require past or future, but now only. The change itself might not, but to perceive something as having changed, e.g. to understand that what is in N state now was in some N - 1 state before, and N - 2 before that, presupposes time (or rather, can be considered the same thing as time). >So we agree in a part that things change state and this is enough to imply growing old and rotating clocks. I don't agree it doesn't matter - as if the time doesn't exist, we don't need to have a pointless discussion about "travelling in time". It wouldn't be pointless as to the actual phenomena we'd experience. It would the same as asking "since we see we can grow old, or see the clock hand rotating, can we somehow manage to go to the now moment when we were young, or where the clock hand was 1 hour before?".
    - madmaniak 8y ago
      So the question is, when you broke a vase can you glue it back to the previous state - and the answer is yes. The more exact state you'd like to achieve the more effort it will require. But having the same state again doesn't mean you've travelled in time, but only that somehow the same state occur one more time (or better to say once again ;) ).
      - kelnos 8y ago
        I think what the parent is getting at is that the progression of states is time. If you think of time as just the entire universe morphing through a progression of different quantum states, and then find a way to modify the quantum state of the entire universe so that it is equivalent to a previous quantum state, then "traveling through time" would easily be a colloquial way of saying what you've done. Though I suppose you didn't really travel; you reset everything -- including yourself -- to a previous state/time. If you could isolate yourself, and then return the rest of the universe to some previous state (while finding a coherent place for your personal newer state in the old rest-of-universe state, possibly editing out the parts of the universe's state that contain the old you), then "traveling" would make more sense. > but only that somehow the same state occur one more time Assuming that state transitions are deterministic (apart from your meddling that allowed you to return to a prior state, that is), then this is equivalent to rolling back time, so the distinction doesn't really matter. If you pick a quantum state that occurred 10 years ago (by your subjective perception of time), then everyone will be 10 years younger, people who were born in the last 10 years will no longer exist, and people who died in the last 10 years will be alive again. Also remember that everyone has their own reference frame when determining time. There's no such thing as "absolute time", or even the absolute passage of time. But that's ok; we don't need that to be the case for this to work out.

coldtea 8y ago

>But this sentence makes it all nonsense - as there's no proof for time existing. First, if we're realists/utilitarian/pragmatists we don't need some fancy proof for time existing. We can see that the material world changes and we call that time. We even measure that passage with clocks. We even know (and have proven experimentally) that things going faster slow down clocks on them. So, whether time "really exists" or not is a meaningless question when we're concerned with time as we experience and know it. It's like someone shooting a bullet at you, and you are asking "yes, but does this bullet _really_ exist?". Well, it might not (e.g. we might all live in a simulation, or the nature of physical objects might be just some probability distribution of information, and not "exist" in the plain sense we understand it), but in this life as we know it, a bullet hitting you will still have the consequences we know and expect. Second, time exists in Relativity equations, so there's that. >Time is a useful abstraction for calculating physical models, making forecasts. As we have other useful abstractions in math or programming - it doesn't make them existing in real world. Doesn't matter. It's enough that we can measure it, we don't care for the "thing in itself" or if it's merely some illusion. We live in a universe where whether it's an illusion or not, it has the same effects for us (e.g. we grow old, things change state, our clock dials rotate).

madmaniak 8y ago
I'm glad you've bothered to answer. I don't need a fancy proof either - any proof would be enough. What we both can agree is that things or processes are happening. They don't need time for that. Constant change, constant mutation doesn't require past or future, but now only. But as I said, we - intelligent species - need a concept of time to predict how the change will proceed. What we measure in clocks depends on a clock - a sand falling down in a sand glass, a pendulum or a spring cycle and so on. After this we make a relation from this event and start to measure other events with it. Still it's just things happening, not a prove of a time existence. If you say that you experience time. Well. That's how neural network works - they are shaped by events/impulses which happened to the network and accessing this information gives you illusion of a past - but this information encoded in your brain exists now. > Doesn't matter. It's enough that we can measure it, we don't care for the "thing in itself" or if it's merely some illusion. We live in a universe where whether it's an illusion or not, it has the same effects for us (e.g. we grow old, things change state, our clock dials rotate). So we agree in a part that things change state and this is enough to imply growing old and rotating clocks. I don't agree it doesn't matter - as if the time doesn't exist, we don't need to have a pointless discussion about "travelling in time".
- coldtea 8y ago
  >Constant change, constant mutation doesn't require past or future, but now only. The change itself might not, but to perceive something as having changed, e.g. to understand that what is in N state now was in some N - 1 state before, and N - 2 before that, presupposes time (or rather, can be considered the same thing as time). >So we agree in a part that things change state and this is enough to imply growing old and rotating clocks. I don't agree it doesn't matter - as if the time doesn't exist, we don't need to have a pointless discussion about "travelling in time". It wouldn't be pointless as to the actual phenomena we'd experience. It would the same as asking "since we see we can grow old, or see the clock hand rotating, can we somehow manage to go to the now moment when we were young, or where the clock hand was 1 hour before?".
  - madmaniak 8y ago
    So the question is, when you broke a vase can you glue it back to the previous state - and the answer is yes. The more exact state you'd like to achieve the more effort it will require. But having the same state again doesn't mean you've travelled in time, but only that somehow the same state occur one more time (or better to say once again ;) ).
    - kelnos 8y ago
      I think what the parent is getting at is that the progression of states is time. If you think of time as just the entire universe morphing through a progression of different quantum states, and then find a way to modify the quantum state of the entire universe so that it is equivalent to a previous quantum state, then "traveling through time" would easily be a colloquial way of saying what you've done. Though I suppose you didn't really travel; you reset everything -- including yourself -- to a previous state/time. If you could isolate yourself, and then return the rest of the universe to some previous state (while finding a coherent place for your personal newer state in the old rest-of-universe state, possibly editing out the parts of the universe's state that contain the old you), then "traveling" would make more sense. > but only that somehow the same state occur one more time Assuming that state transitions are deterministic (apart from your meddling that allowed you to return to a prior state, that is), then this is equivalent to rolling back time, so the distinction doesn't really matter. If you pick a quantum state that occurred 10 years ago (by your subjective perception of time), then everyone will be 10 years younger, people who were born in the last 10 years will no longer exist, and people who died in the last 10 years will be alive again. Also remember that everyone has their own reference frame when determining time. There's no such thing as "absolute time", or even the absolute passage of time. But that's ok; we don't need that to be the case for this to work out.