Is time physical?

[seer]

Personally I think time does go in one direction, and that is why we experience it that way, because God designed it that way.

But there is no actual direction in B theory, God not withstanding....

[Sparko]

Well I did quote Sean Carroll:

if entropy is ultimately based on the underlying laws of the universe, and those laws are the same going forward and backward, then entropy is just as likely to increase going backward in time. But no one believes that entropy actually works that way. Scrambled eggs always come after whole eggs, never the other way around.





It is not question of thinking backward. The question is why don't we have knowledge of the future as well as the past. What makes the past and present privileged over the future when it comes to knowledge?

Again, maybe it's just the way our brains work? You are assuming it's the universe doing it, but maybe it's all our subjective perception because that is the way our brains work. I am just giving you an explanation using your own claims that time is an illusion.

Personally I think time does go in one direction, and that is why we experience it that way, because God designed it that way.

[Stoic]

Nothing would make sense if it went backwards. All logic would be illogical. There is no reason that I have seen that it can't or won't happen.

The reason it can't go backwards is probabilistic. Every individual particle interaction may be reversible, but in the aggregate, how they go is predictable.

Imagine a supernova. When it explodes, photons and other particles are sent at very high energies in all directions. Some of those photons travel millions of light-years, and end up passing through a telescope and hitting a sensor which records their arrival. In theory, that detector could just randomly emit photons going in exactly the opposite direction, with exactly the right energy. Also in theory, every other place where a particle ends up could eject such a particle in the exact opposite direction at exactly the right time, in exactly the right direction, and with exactly the right energy, so that all those particles end up at the location of the supernova at exactly the right time to create a star where there wasn't one before. I'm not sure we even have the numbers to say just how improbable such a thing would be.

Similarly, the 2nd law of thermodynamics says that heat will always flow from a warmer body to a cooler one. But the reason for this is probabilistic, not based on the underlying laws of the universe. In theory, it could go either way, but
there are so many more ways for energy to transfer in one direction than the other, there is no practical chance for it to go backwards.

If it does, we're left with a universe that makes no sense. Because the Block Universe does not have any particular orientation, and no reason as to why the arrow of time should go in any certain direction, B theory allows for an irrational universe.

I don't remember anyone saying the block universe has no particular orientation. It comes from physicists, after all, and I think they are pretty unanimous in thinking that time has a direction, even if that direction is only apparent from the point of view of an observer within the block universe.

[seer]

We have already had this discussion: Entropy. Why does entropy work in one direction? I have no clue. Ask a scientist....

Well I did quote Sean Carroll:

if entropy is ultimately based on the underlying laws of the universe, and those laws are the same going forward and backward, then entropy is just as likely to increase going backward in time. But no one believes that entropy actually works that way. Scrambled eggs always come after whole eggs, never the other way around.

But if you are correct and there is no direction of time, and it is all an illusion, then the only thing that creates that illusion is the way our brains work. Our brains remember in one direction. And we call that direction "the past" and what we don't see yet is "the future" - at any given moment in our lives the past is what we remember and the future is what we don't. So in 1974, everything you remember was 1974 and before and 1975 and beyond was "the future" for Seer at that moment. in 2022, 2022 and before is the past of Seer of 2022 and 2023 and beyond is your future. In 2030, 2030 and before is the past of that version of you, and 2031 and beyond is his future and so on.

so the b-theory doesn't create that, our brains do.

Maybe somewhere in the galaxy there are aliens whose brains work backwards and they remember the future and don't know the past. They would be asking the same question but wondering why time only goes in the opposite direction.

It is not question of thinking backward. The question is why don't we have knowledge of the future as well as the past. What makes the past and present privileged over the future when it comes to knowledge?

[Sparko]

I guess the question is why would there be a direction of time in static time? Then the question would be why would we have memories of the past and not the future - why would B theory create that illusion?

We have already had this discussion: Entropy. Why does entropy work in one direction? I have no clue. Ask a scientist. But if you are correct and there is no direction of time, and it is all an illusion, then the only thing that creates that illusion is the way our brains work. Our brains remember in one direction. And we call that direction "the past" and what we don't see yet is "the future" - at any given moment in our lives the past is what we remember and the future is what we don't. So in 1974, everything you remember was 1974 and before and 1975 and beyond was "the future" for Seer at that moment. in 2022, 2022 and before is the past of Seer of 2022 and 2023 and beyond is your future. In 2030, 2030 and before is the past of that version of you, and 2031 and beyond is his future and so on.

so the b-theory doesn't create that, our brains do.

Maybe somewhere in the galaxy there are aliens whose brains work backwards and they remember the future and don't know the past. They would be asking the same question but wondering why time only goes in the opposite direction.

[seer]

Well either there is a direction of time in the block universe, or it's just another illusion created by the way our brains work. As I said we can only remember what we call the past therefore we experience the past as having already happened and the future as not happening yet. If our brains worked the other way, remembering the future, then we would think what we now call the future as the "past" and what we call the past as the "future".

I guess the question is why would there be a direction of time in static time? Then the question would be why would we have memories of the past and not the future - why would B theory create that illusion?

[Sparko]

The question is, why is there a time line (or arrow of time) in the first place? Why does entropy only work one way (the question Sean Carroll asked)? In block theory there is no actual direction of time.

Well either there is a direction of time in the block universe, or it's just another illusion created by the way our brains work. As I said we can only remember what we call the past therefore we experience the past as having already happened and the future as not happening yet. If our brains worked the other way, remembering the future, then we would think what we now call the future as the "past" and what we call the past as the "future".

[seer]

We would just see what we call the effect as the cause. For example we would think that explosions cause bombs. That chemicals in graves come together to form corpses which become old people who eventually enter their mother's wombs and cease to exist.

The question is, why is there a time line (or arrow of time) in the first place? Why does entropy only work one way (the question Sean Carroll asked)? In block theory there is no actual direction of time.

[Sparko]

Nothing would make sense if it went backwards. All logic would be illogical. There is no reason that I have seen that it can't or won't happen. If it does, we're left with a universe that makes no sense. Because the Block Universe does not have any particular orientation, and no reason as to why the arrow of time should go in any certain direction, B theory allows for an irrational universe.

We would just see what we call the effect as the cause. For example we would think that explosions cause bombs. That chemicals in graves come together to form corpses which become old people who eventually enter their mother's wombs and cease to exist.

[seer]

Block Universe does not have any particular orientation, and no reason as to why the arrow of time should go in any certain direction, B theory allows for an irrational universe.

That is a good point, why would there be an arrow of time or correlating entropy in the first place?

[seer]

If you think that contradicts anything I've said, you are once again mistaken.

Let's see what your friend Sean Carroll thinks about the Block Universe:

Perhaps the strongest statement made at the conference in favor of the block universe’s compatibility with everyday experience came from the philosopher Jenann Ismael of the University of Arizona. The way Ismael sees it, the block universe, properly understood, holds within it the explanation for our experience of time’s apparent passage. A careful look at conventional physics, supplemented by what we’ve learned in recent decades from cognitive science and psychology, can recover “the flow, the whoosh, of experience,” she said. In this view, time is not an illusion — in fact, we experience it directly. She cited studies that show that each moment we experience represents a finite interval of time. In other words, we don’t infer the flow of time; it’s part of the experience itself. The challenge, she said, is to frame this first-person experience within the static block offered by physics — to examine “how the world looks from the evolving frame of reference of an embedded perceiver” whose history is represented by a curve within the space-time of the block universe.

Ismael’s presentation drew a mixed response. Carroll said he agreed with everything she had said;

Yes, I watch one of his videos on the subject. He holds to the block universe but that doesn't change his point that we should see entropy both forward and backward, if entropy is a fundamental principle.As far as what Carroll agrees with here is simply about our experience of time.

[Machinist]

That's probably true, but if entropy is the reason our brains remember the past instead of the future, and entropy only works in one direction, that's just another way of saying that we can't experience our lives backwards.

Nothing would make sense if it went backwards. All logic would be illogical. There is no reason that I have seen that it can't or won't happen. If it does, we're left with a universe that makes no sense. Because the Block Universe does not have any particular orientation, and no reason as to why the arrow of time should go in any certain direction, B theory allows for an irrational universe.

[Stoic]

If our brains worked by remembering the future instead of the past, perhaps then we would experience our lives backwards? At any given moment in our lives our memories would consist of everything that happened since we died rather than everything that happened since we were born.

That's probably true, but if entropy is the reason our brains remember the past instead of the future, and entropy only works in one direction, that's just another way of saying that we can't experience our lives backwards.

[Stoic]

To quote Sean Carroll again:

if entropy is ultimately based on the underlying laws of the universe, and those laws are the same going forward and backward, then entropy is just as likely to increase going backward in time. But no one believes that entropy actually works that way. Scrambled eggs always come after whole eggs, never the other way around.

If you think that contradicts anything I've said, you are once again mistaken.

Let's see what your friend Sean Carroll thinks about the Block Universe:

Perhaps the strongest statement made at the conference in favor of the block universe’s compatibility with everyday experience came from the philosopher Jenann Ismael of the University of Arizona. The way Ismael sees it, the block universe, properly understood, holds within it the explanation for our experience of time’s apparent passage. A careful look at conventional physics, supplemented by what we’ve learned in recent decades from cognitive science and psychology, can recover “the flow, the whoosh, of experience,” she said. In this view, time is not an illusion — in fact, we experience it directly. She cited studies that show that each moment we experience represents a finite interval of time. In other words, we don’t infer the flow of time; it’s part of the experience itself. The challenge, she said, is to frame this first-person experience within the static block offered by physics — to examine “how the world looks from the evolving frame of reference of an embedded perceiver” whose history is represented by a curve within the space-time of the block universe.

Ismael’s presentation drew a mixed response. Carroll said he agreed with everything she had said;

[Sparko]

One common explanation for the arrow of time is entropy, since entropy always increases with time (2nd law of thermodynamics). But the 2nd law can be expressed in terms of an A series (entropy in the past is always less than in the present, which is always less than in the future) or a B series (entropy is always less at earlier times than at later times). So the 2nd law is consistent with a Block Universe.

Incidentally, entropy is also given as a reason for why we can remember the past, but not the future, since storing memories involves an increase in entropy. (There are multiple explanations for why storing memories increases entropy, and I don't think there is complete agreement about it.)

If our brains worked by remembering the future instead of the past, perhaps then we would experience our lives backwards? At any given moment in our lives our memories would consist of everything that happened since we died rather than everything that happened since we were born.