Help me understand why “Block Universe” is not scientifically proven

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From online sources, I’ve found that the Block Universe interpretation has been take and “real”. Is this correct, otherwise, can you give me examples of experimental data that challenges it so I can better understand it?
Hello!
I’m a philosopher getting into philosophy of science, and I’ve found many physicists claiming that “block universe” theory is a necessary interpretation from relativity.

From what I’ve learned, I’ve found that, while relativity challenges traditional notions of “presentism” , it doesn’t have to lead to Block Universe as the necessary interpretation of time.

I talked to a physicist in my university that explained that quantum indeterminism, and recent findings on dynamic dark energy, challenge this notion of a block universe, but some physicists decide that they must “believe” it to be true as it is the most popular interpretation due to lack of evidence that conclusively contradicts it.

My understanding of physics is amateurish at best, so I was wondering if you could provide examples of experimental data or knowledge that challenges the Block Universe interpretation, or alternative valid interpretations.

Thanks in advance!
 
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There is no experimental data that directly confirm or reject the block universe interpretation. It's a purely theoretical or philosophical concept. The block universe interpretation is the simplest interpretation of spacetime as described by the theory of relativity. But block universe interpretation also clashes with our intuitive notion of time, which is why it is not generally accepted in the community.

For more details see also
https://en.wikipedia.org/wiki/Eternalism_(philosophy_of_time)

For my own views you may take a look at https://citeseerx.ist.psu.edu/docum...&doi=9dea2b37d7db4a9c386118157152a8975872678a
 
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Demystifier said:
There is no experimental data that directly confirm or reject the block universe interpretation. It's a purely theoretical or philosophical concept. The block universe interpretation is the simplest interpretation of spacetime as described by the theory of relativity. But block universe interpretation also clashes with our intuitive notion of time, which is why it is not generally accepted in the community.

For more details see also
https://en.wikipedia.org/wiki/Eternalism_(philosophy_of_time)

For my own views you may take a look at https://citeseerx.ist.psu.edu/docum...&doi=9dea2b37d7db4a9c386118157152a8975872678a
Thank you! I’ve worked and talked with scientists, and I’ve come to find that the distinction between pime and time to be hard to distinguish for a lot of people conceptually.
What do you think about growing block and similar theories? I like that they can reconcile our understanding of time and relativity.

Also, could you expand on why the arrow of time in thermodynamics is seen as a challenge to a block universe?
 
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Moderator's note: Thread moved to the relativity forum. Block universe is an interpretation of relativity, not quantum mechanics.
 
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ojitojuntos said:
From what I’ve learned
Where? You need to give some specific references.

ojitojuntos said:
I talked to a physicist in my university that explained that quantum indeterminism
Block universe is an interpretation of relativity, not quantum mechanics.
 
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ojitojuntos said:
Thank you! I’ve worked and talked with scientists, and I’ve come to find that the distinction between pime and time to be hard to distinguish for a lot of people conceptually.
What do you think about growing block and similar theories? I like that they can reconcile our understanding of time and relativity.
Also, could you expand on why the arrow of time in thermodynamics is seen as a challenge to a block universe?
It may be worth while taking some time to learn the theory of special relativity. In fact, if you are serious about studying the philosophy of science, is it not essential to understand the theories you are talking about? A similar case could be made for quantum mechanics.

Unless you can grasp these concepts yourself, I don't see how you can understand what physicists are telling you.

PS outside the arena of strict mathematical or experimental physics, physicists can talk as much nonsense as anyone else - and have the same philosophical or religious prejudices. I'd be especially wary of anything in the domain of so-called "popular science".
 
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ojitojuntos said:
TL;DR Summary: From online sources, I’ve found that the Block Universe interpretation has been take and “real”. Is this correct, otherwise, can you give me examples of experimental data that challenges it so I can better understand it?

Hello!
I’m a philosopher getting into philosophy of science, and I’ve found many physicists claiming that “block universe” theory is a necessary interpretation from relativity.
From what I’ve learned, I’ve found that, while relativity challenges traditional notions of “presentism” , it doesn’t have to lead to Block Universe as the necessary interpretation of time.
I talked to a physicist in my university that explained that quantum indeterminism, and recent findings on dynamic dark energy, challenge this notion of a block universe, but some physicists decide that they must “believe” it to be true as it is the most popular interpretation due to lack of evidence that conclusively contradicts it.
My understanding of physics is amateurish at best, so I was wondering if you could provide examples of experimental data or knowledge that challenges the Block Universe interpretation, or alternative valid interpretations.
Thanks in advance!
Broadly speaking, I agree with @Demystifier's first reply to you: "There is no experimental data that directly confirm or reject the block universe interpretation." I think, however, that Harvey Brown's book "Physical Relativity", which won the Lakatos Award in 2006, is not mentioned in the links he provided and will be rewarding as a perspective from within Philosophy of Physics.

The collapse of the wave function is indeed taken by some to cast doubt on the block world, however that depends on which interpretation of QM we use. Particularly for more epistemological interpretations, 'collapse' is more about our knowledge of the world than about how-the-world-really-is, so that collapse has little to say about an ontological concept such as the block world. For interpretations of quantum field theory, a key question is whether a given whole theoretical structure is Lorentz invariant or not, which is hard to be sure of because we have no generally accepted set of axioms that has physically relevant interacting QFT models, because of renormalization and other concerns.
 
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ojitojuntos said:
TL;DR Summary: From online sources, I’ve found that the Block Universe interpretation has been take and “real”. Is this correct, otherwise, can you give me examples of experimental data that challenges it so I can better understand it?

I was wondering if you could provide examples of experimental data or knowledge that challenges the Block Universe interpretation, or alternative valid interpretations
There is no such data nor can there be such data.

In science there are theories and interpretations. The theories consist of a mathematical framework and a mapping between the mathematics and experiments. This mapping between the math and experiments is called the minimal interpretation.

Often, however, people like to add more philosophical structure, on top of the minimal interpretation. These additional philosophical structures are called interpretations. Often they include statements about what things in the math correspond to some underlying reality.

Experimental evidence can distinguish one theory from another, but cannot even in principle distinguish between two interpretations of the same theory.

So, if different interpretations of a theory cannot be scientifically distinguished, why bother? Indeed, some don’t bother, considering the minimal interpretation to be sufficient and anything else to be merely a human construction. However, interpretations can be useful. They can serve as mnemonic devices to help organize your thoughts and analysis. And since there can be no evidence for or against any of them, you are always free to use whichever seems convenient for a particular scenario.

Personally, I find the block universe interpretation to be the most generally useful interpretation of SR. However, I like to use the Lotentzian interpretation for relativistic Doppler questions. I am free to do so precisely because there can be no experimental evidence for an interpretation, only for or against a theory.

One big problem I have with philosophers is that they are missing the whole point. They try to prove or disprove interpretations and make assertions about whether a given interpretation is true or false. That just isn’t a relevant question. The relevant question is whether a given interpretation is useful or not. For whatever reason, philosophers are not typically focused on this question which is actually important.
 
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  • #10
ojitojuntos said:
I’m a philosopher getting into philosophy of science, and I’ve found many physicists claiming that “block universe” theory is a necessary interpretation from relativity.
You are mixing up two fundamentally different concepts: theories and interpretations. The block universe is an interpretation, not a theory.

Also, you asked about proof. Theories are never proven, they do get support from observation and experiment. Often the support is so overwhelming that we think of it as proof.

None of this applies to interpretations. A theory can have more than one interpretation, with experiment and observation providing no evidence that any one interpretation is more valid than another.

Such is the case for the block universe interpration of Einstein's theory of relativity.
 
  • #11
To me the Block Universe idea, depending on what you mean by it, is either a trivial observation or a meaningless philosophical claim.
 
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  • #12
martinbn said:
To me the Block Universe idea, depending on what you mean by it, is either a trivial observation or a meaningless philosophical claim.
That's because you think of a time from a purely mathematical perspective.
 
  • #13
Demystifier said:
That's because you think of a time from a purely mathematical perspective.
This is last three words if my previous post.
 
  • #14
Demystifier said:
That's because you think of a time from a purely mathematical perspective.
I think I heard that very near a black hole the time coordinate becomes a spatial coordinate and vice versa.
I am not sure if it was in the course I had taken years ago, from a YT video or Schutz's book.
Mathematically I can understand it, but from eveyday life not so much.
 
  • #15
mad mathematician said:
think I heard that very near a black hole the time coordinate becomes a spatial coordinate and vice versa.
It's one of the popsci nonsense claims.

Schwarzschild coordinates are actually two disjoint sets of coordinates, one set covering the interior of the black hole and one set covering the exterior. Neither set covers the event horizon and it's not possible to smoothly join the two sets because of this. However, the metric component associated with the timelike coordinate inside the hole has the same functional form as the one associated with the radial coordinate outside and vice versa. So it's not wrong to notice that the metric components swapped functional form, but some people read weird things into it.

Mathematically, it's similar to walking through the north pole, where forward and backward suddenly switch from being north and south to being south and north. I mean, yeah, I guess so, but I wouldn't take to YouTube to make breathless videos about forward and backward changing meaning at the poles.

This isn't related to the block universe, though. You can make poor choices of coordinates independent of your interpretation of the underlying physics.
 
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  • #16
Dale said:
There is no such data nor can there be such data.

In science there are theories and interpretations. The theories consist of a mathematical framework and a mapping between the mathematics and experiments. This mapping between the math and experiments is called the minimal interpretation.

Often, however, people like to add more philosophical structure, on top of the minimal interpretation. These additional philosophical structures are called interpretations. Often they include statements about what things in the math correspond to some underlying reality.

Experimental evidence can distinguish one theory from another, but cannot even in principle distinguish between two interpretations of the same theory.

So, if different interpretations of a theory cannot be scientifically distinguished, why bother? Indeed, some don’t bother, considering the minimal interpretation to be sufficient and anything else to be merely a human construction. However, interpretations can be useful. They can serve as mnemonic devices to help organize your thoughts and analysis. And since there can be no evidence for or against any of them, you are always free to use whichever seems convenient for a particular scenario.

Personally, I find the block universe interpretation to be the most generally useful interpretation of SR. However, I like to use the Lotentzian interpretation for relativistic Doppler questions. I am free to do so precisely because there can be no experimental evidence for an interpretation, only for or against a theory.

One big problem I have with philosophers is that they are missing the whole point. They try to prove or disprove interpretations and make assertions about whether a given interpretation is true or false. That just isn’t a relevant question. The relevant question is whether a given interpretation is useful or not. For whatever reason, philosophers are not typically focused on this question which is actually important.
Thanks a lot for this reply, it was very insightful. As a layman, I've had some trouble recognizing why I've found so many resources treating the Block Universe as a necessary consequence of relativity (maybe I'm paying too much attention to pop-sci), especially since, as per my understanding, the probabilistic nature of quantum mechanics provides a challenge to the idea of a static block.

Am I misunderstanding this? I understand that, experimentally, there is no way to prove or disprove this claim, regardless of how much sense it makes mathematically. But, if quantum mechanics' probabilistic aspect has been experimentally proved time and again, why do you think that the block universe keeps getting pushed as the nature of the universe by prominent pop-sci figures like Sean Carroll?
 
  • #17
I think that the probabilistic nature of QM and the block universe concept are rather unrelated. Neither precludes the other. Modern QFT is fully compatible with SR, so it is also compatible with both block universe and LET.
 
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Dale said:
I think that the probabilistic nature of QM and the block universe concept are rather unrelated. Neither precludes the other. Modern QFT is fully compatible with SR.
Thank you for your response! Can you elaborate on this? I understood that the block universe implies that all events are “fixed” in space time, but the probabilistic aspect of quantum challenges this, no? I’m sorry if I’m being too daft.
I
 
  • #19
ojitojuntos said:
I understood that the block universe implies that all events are “fixed” in space time, but the probabilistic aspect of quantum challenges this, no?
What specific experimental outcome would be incompatible with it? The idea of a random variable (RV) is not in any way contradicted by it assuming a specific definite value at some specific event. So the fact that the RV assumed some value in a given experiment is compatible with QFT, and because it assumed that value the BU simply says that value at that event is “fixed”
 
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ojitojuntos said:
I understood that the block universe implies that all events are “fixed” in space time, but the probabilistic aspect of quantum challenges this, no?
No, because if we accept the block universe interpretation then the apparently probabilistic nature of quantum measurements reflects our ignorance of the result until we've looked, not that the result is randomly chosen when we look.
There's no problem with Bell's theorem here, because block universe implies superdeterminism (the measurement result was fixed in spacetime, but so was the choice of measurement) and Bell's theorem does not apply to superdeterministic theories.
 
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  • #21
Thank you all for your replies, it helps me better understand how to approach this.
If I understand correctly: as far as we know, the BU is just an interpretation, it is not taken as a necessary, or unique consequence of SR.
Due to this, unless we can experimentally confirm or deny it, it is not even a theory, right?
That’s why it can be compatible with QM, because if we assume it as true, it inherently dictates that the probabilistic aspect of QM that we’ve experimentally confirmed are due to a fundamental epistemic limitation, no?
As a final question, in your experience, how often do colleagues believe that the BU is the correct representation of time? Do you have a preference?
 
  • #22
ojitojuntos said:
Due to this, unless we can experimentally confirm or deny it, it is not even a theory, right?
Yes. Interpretations are not theories. That includes the block universe.

ojitojuntos said:
As a final question, in your experience, how often do colleagues believe that the BU is the correct representation of time?
As I said above

Dale said:
One big problem I have with philosophers is that they are missing the whole point. They try to prove or disprove interpretations and make assertions about whether a given interpretation is true or false. That just isn’t a relevant question. The relevant question is whether a given interpretation is useful or not. For whatever reason, philosophers are not typically focused on this question which is actually important.
I don’t think any interpretation of any theory is “true” or “correct”. The question isn’t even relevant.

Block universe is useful. That is all an interpretation can be.
 
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  • #23
ojitojuntos said:
I understood that the block universe implies that all events are “fixed” in space time, but the probabilistic aspect of quantum challenges this, no?
The block universe is an interpretation of classical (non-quantum) relativity. Whether it is compatible with quantum mechanics depends on interpretation of quantum mechanics. It is quite compatible with deterministic interpretations such as many worlds and Bohmian. But it is much more difficult to make it compatible with Copenhagen-like interpretations.
 
  • #24
Nugatory said:
There's no problem with Bell's theorem here, because block universe implies superdeterminism (the measurement result was fixed in spacetime, but so was the choice of measurement) and Bell's theorem does not apply to superdeterministic theories.
You are right that Bell's theorem does not apply to superdeterministic theories, but block universe does not imply superdeterminism. Many worlds and Bohmian interpretation are also compatible with block universe, but they are not superdeterministic, they are just deterministic. Superdeterminism is not merely an assumption that everything, including the choice of measurement, is predetermined; that's just determinism. The "super" in superdeterminism is an assumption that there is also some law which restricts the initial conditions, which implies some additional regularities that cannot be explained by pure determinism. In the context of Bell's theorem, this restriction on initial conditions is supposed to explain non-local quantum correlations with hidden variables that do not entail spooky action at a distance.
 
  • #25
Note that by "determinism" in physics one usually means that the state of the universe at time ##t+1## is a function of its state at time ##t##. The block universe does not imply this kind of determinism and is hence quite compatible with probabilistic or random physics.
 
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ojitojuntos said:
I’m a philosopher getting into philosophy of science, and I’ve found many physicists claiming that “block universe” theory is a necessary interpretation from relativity.

Possibly interesting reading:

Prediction in General Relativity
Geroch, Robert (1977)
https://conservancy.umn.edu/items/7fa97a8c-65c0-4675-964f-3e25f1cfbf58
and
others from
Minnesota Studies in the Philosophy of Science
Volume 08 (1977): Foundations of space-time theories
https://conservancy.umn.edu/collections/968a8eb0-e5c4-4d65-80e4-74ef7c6ea463
 
  • #27
ersmith said:
Note that by "determinism" in physics one usually means that the state of the universe at time ##t+1## is a function of its state at time ##t##. The block universe does not imply this kind of determinism and is hence quite compatible with probabilistic or random physics.
Right, block universe does not imply determinism. But does determinism imply block universe?
 
  • #28
Demystifier said:
Right, block universe does not imply determinism. But does determinism imply block universe?
No, determinism is compatible with presentism and other interpretations as well. Basically determinism and the block universe are independent concepts.
 
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  • #29
Demystifier said:
Right, block universe does not imply determinism. But does determinism imply block universe?
Here's a mathematical analogy. The concept of a sequence, that is to say a function on the natural numbers is like the eternal block universe. The sequence exists as a mathematical object in its own right. The elements of the sequence may be defined using a recurrence relation, which can be probabilistic or not. Or, there may be no relationship between the elements. Mathematically it is sufficient to declare that ##\{x_n\}## is an infinite sequence.

The physical evolution model, if I can call it that, is analogous to a process, probabilistic or not, that produces a finite sequence one element at a time. In this case, we would always be talking about a finite sequence of arbitrary length. We never have an infinite sequence in this case.

In this analogy, how we generate each element of the sequence is independent of whether we are talking about an infinite sequence or a finite sequence of arbitrary length.
 
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  • #30
Thank you all for the discussion and patience! I have another question. As you can see I’m also interested in how physicists deal with these questions, and you’ve helped me understand how you deal with interpretations (I have now seen that I spent too much time in popsci articles and Reddit haha).
The question is the following: is it true that, according to relativity, all events in spacetime are “fixed”? This is something I’ve read in these places I mentioned, but I would like to know if this is just an extrapolation of the math of SR. Thanks in advance!
 
  • #31
ojitojuntos said:
is it true that, according to relativity, all events in spacetime are “fixed”?
The concept of an event being "fixed" or not is not part of the math, nor is it part of any experiment. It is only part of the block universe interpretation. The math just tells you that if ##(t,x,y,z)## are the coordinates of the event in one frame then ##(t',x',y',z')## are the coordinates in another frame. More physically, it says that the quantity ##ds^2=-c^2 dt^2+dx^2+dy^2+dz^2## is invariant. There is no mathematical representation of the block universe concept of "fixed", nor is there an experimental meaning to it.
 
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  • #32
Dale said:
The concept of an event being "fixed" or not is not part of the math, nor is it part of any experiment. It is only part of the block universe interpretation. The math just tells you that if ##(t,x,y,z)## are the coordinates of the event in one frame then ##(t',x',y',z')## are the coordinates in another frame. More physically, it says that the quantity ##ds^2=-c^2 dt^2+dx^2+dy^2+dz^2## is invariant. There is no mathematical representation of the block universe concept of "fixed", nor is there an experimental meaning to it.

Thank you for the clarification. I think that part of my confusion comes due to the adamant defense of the block universe concept by some speakers, like Sean Carrol.
I’ve read about SR in the last months since I asked this question, and I don’t see why the block universe is treated as a “natural conclusion” of relativity.
 
  • #33
ojitojuntos said:
I don’t see why the block universe is treated as a “natural conclusion” of relativity.
Any such statement is an OPINION (or possibly an interpretation --- same thing), not a scientific fact.
 
  • #34
And regardless of the expertise or assertiveness of the opinion holder, it remains an opinion.

ojitojuntos said:
I don’t see why the block universe is treated as a “natural conclusion” of relativity.
It is a natural conclusion in the sense that given the math of relativity it is natural that many people would hold that opinion.
 
  • #35
ojitojuntos said:
’ve read about SR in the last months since I asked this question, and I don’t see why the block universe is treated as a “natural conclusion” of relativity.
I'd say that the block universe has the least philosophical baggage (not counting "shut up and calculate"). The observation that the maths of coordinates in relativity is the same as the maths of Minkowski space is unarguable, so the interpretation aspect is basically "let's take that literally". On the other hand, LET and hybrid ideas like a growing block universe also need a global boundary between past and future which is undetectable even in principle. So something that is absolutely critical to the model but of zero consequence in practice and hence completely arbitrary.

So I think one can argue for the block universe as being the simplest interpretation in an Occam's Razor sense. I don't know that I would call it the "natural" interpretation though - that would be a matter of opinion, in my opinion anyway.
 
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