https://backreaction.blogspot.com/2022/0...exist.html
EXCERPTS: . . . Let’s then put all those together. If you are comfortable with saying that something, anything, exists “now” which isn’t here, then, according to Einstein’s fourth assumption, this must be the case for all observers. But if all the events that you think happen “now” exist and all other observers say the events that happen at the same time as those events, then all events exist “now”. Another way to put it is that all times exist in the same way.
This is called the “block universe”. It’s just there. It doesn’t come into being, it doesn’t change. It just sits there.
[...] If you find that somewhat hard to accept, there is another possibility to consistently combine a notion of existence with Einstein’s Special Relativity. All that I just said came from assuming that you are willing to say something exists now even though you can’t see or experience it in any way. If you are willing to say that only things exist which are now and here, then you don’t get a block universe. But maybe that’s even more difficult to accept.
Another option is to simply invent a notion of “existence” and define it to be a particular slice in space-time for each moment in time. This is called a “slicing” but unfortunately it has nothing to do with pizza. If it had any observable consequences, that would contradict the fourth assumption Einstein made. So it’s in conflict with Special Relativity and since this theory is experimentally extremely well confirmed, this would almost certainly mean the idea is in conflict with observation. But if you just want to define a “now” that doesn’t have observable consequences, you can do that. Though I’m not sure why you would want to.
Quantum mechanics doesn’t change anything about the block universe because it’s still compatible with Special Relativity. The measurement update of the wave-function, which I talked about in this earlier video, happens faster than the speed of light. If it could be observed, you could use it to define a notion of simultaneity. But it can’t be observed, so there’s no contradiction.
Some people have argued that since quantum mechanics is indeterministic, the future can’t already exist in the block universe, and that therefore there must also be a special moment of “now” that divides the past from the future. And maybe that is so. But even if that was the case, the previous argument still applies to the past. So, yeah, it’s true. For all we currently know, the past exists the same way as the present... (MORE - missing details) ..... RELATED: Growing block universe
https://youtu.be/GwzN5YwMzv0
https://www.youtube-nocookie.com/embed/GwzN5YwMzv0
EXCERPTS: . . . Let’s then put all those together. If you are comfortable with saying that something, anything, exists “now” which isn’t here, then, according to Einstein’s fourth assumption, this must be the case for all observers. But if all the events that you think happen “now” exist and all other observers say the events that happen at the same time as those events, then all events exist “now”. Another way to put it is that all times exist in the same way.
This is called the “block universe”. It’s just there. It doesn’t come into being, it doesn’t change. It just sits there.
[...] If you find that somewhat hard to accept, there is another possibility to consistently combine a notion of existence with Einstein’s Special Relativity. All that I just said came from assuming that you are willing to say something exists now even though you can’t see or experience it in any way. If you are willing to say that only things exist which are now and here, then you don’t get a block universe. But maybe that’s even more difficult to accept.
Another option is to simply invent a notion of “existence” and define it to be a particular slice in space-time for each moment in time. This is called a “slicing” but unfortunately it has nothing to do with pizza. If it had any observable consequences, that would contradict the fourth assumption Einstein made. So it’s in conflict with Special Relativity and since this theory is experimentally extremely well confirmed, this would almost certainly mean the idea is in conflict with observation. But if you just want to define a “now” that doesn’t have observable consequences, you can do that. Though I’m not sure why you would want to.
Quantum mechanics doesn’t change anything about the block universe because it’s still compatible with Special Relativity. The measurement update of the wave-function, which I talked about in this earlier video, happens faster than the speed of light. If it could be observed, you could use it to define a notion of simultaneity. But it can’t be observed, so there’s no contradiction.
Some people have argued that since quantum mechanics is indeterministic, the future can’t already exist in the block universe, and that therefore there must also be a special moment of “now” that divides the past from the future. And maybe that is so. But even if that was the case, the previous argument still applies to the past. So, yeah, it’s true. For all we currently know, the past exists the same way as the present... (MORE - missing details) ..... RELATED: Growing block universe
https://youtu.be/GwzN5YwMzv0