The BLOCK Universe idea

[Catastrophe]

Some were not so happy with the BLOCK model: (From Wiki)

"Avshalom Elitzur vehemently rejects the block universe interpretation of time. At the Time in Cosmology conference, held at the Perimeter Institute for Theoretical Physics in 2016, Elitzur said: "I’m sick and tired of this block universe, ... I don’t think that next Thursday has the same footing as this Thursday. The future does not exist. It does not! Ontologically, it’s not there."

Cat

 

[Catastrophe]

I have been thinking a lot about the BLOCK model. Leave aside, for the moment, the question of how it came about, I want to address the question of Time Travel. N.B. I m not promoting this model, but just enjoying a thought experiment.

We must be very clear about the suggestions of the block model. Each individual (and object) has a world line or time line which appears in spacetime. Your world line begins at birth, the separation of your individuality from the world line of your mother. The world line then continues until death. This world line is supposed to be "real" at all points. Some limitation in our perceptive mechanisms means that we can only cope with one "now" at a time.

Now, Time Travel would involve receiving information in some form from "other" parts of your worldline. For your "physical body" to visit other parts of your world line, it would have to have been built into the world line. The only question is whether some non-physical 'you' would have to be responsible for collection of information. Would this have to have been built into the world line? If so, where does it stop? There is a great danger of falling into a totally deterministic situation where, right back to the Heisenberg Uncertainty principle,

Is the BLOCK model suggesting that worldlines are world lines of consciousness, rather than of baryonic matter. What then about objects. We are in danger of a philosophical mire.

Whether the situation is fluid, or an exact parallel of what is available to the conscious element of our worldline, we do not know. What I mean by that, is do we think about our past - just another "real" component of our world line - or is there some superconscious element of our identity which can overcome the perception limitation and "oversee" different "now's" in the worldline, or even other worldlines.

The answer, of course, is that we do not know.

Cat

 

[Unclear Engineer]

My concerns with the Block Universe model are the "lessons" that some might take from it, to their own detriment and that of society overall.

If the future is already determined, then what is the point of making efforts to change the perceived direction toward an unfavorable outcome? Why not just "enjoy life" now and see what is going to happen when it happens, because putting a lot of unenjoyable effort out now will in no way make any difference in tomorrow, assuming that the Block Model is true.

With no way to prevent pre-determined bad future events or to lose out on pre-determined good future events, why be a "good" person who exercises self-control? If you feel like murdering somebody, why not just do it, because you are going to do it anyway and get caught or get away with it, no matter what you think you choose to do. So why bother to think about it? When somebody asks how you could do such a terrible thing, the defense is that "The Block Universe made me do it - an had no alternative - not my fault."

Basing real behavior on an unverified theory would be stupid if it creates new risks that could be addressed constructively if a different theory is followed and turns out to be true.

So, while I see no problem with kicking around a thought to see whether it can teach us anything, I see no evidence to support the reality of a Block Universe. Making some supposedly descriptive mathematics "work" is not the same as truly representing reality.

Popular media stories that make it sound like the future it predetermined and unavoidable, even if unknowable. are just what some sick minds will latch onto to avoid taking responsibility for their anti-social actions. So, it is not a theory that I would want anybody to think has any significant probability for being true.

But, if it is true, then there is no need for "believers" to make any effort to convince the rest of us, because we will either become convinced or not in the future, not matter what they say now. But, maybe they just can't stop themselves, because the Block Universe is making them do it. ;-)

 

[Catastrophe]

UE, I totally agree with your comments in the BLOCK model regarding determinism. I have always made it clear that I am just putting the idea up for comment or possible refinement.

I am, perhaps, surprised that no one has at least pointed to the world lines, and asked "who wrote the book". That is my biggest and, in my view, overwhelming objection to the BLOCK MODEL. That, and the question as to whether every object, down to subatomic particles, has a world line.

Cat

 

[Unclear Engineer]

"Who wrote the book?" is just the equivalent of "What created the Big Bang out of nothing?"
Any theory that postulates a beginning needs something to answer why and how there was a beginning, if it is assuming that there was nothing before, not even time.

I find it easier mentally to accept that there was no beginning of "everything", and there will be no end of everything. I see that most everything keeps changing with time, and don't see how it is completely reversible (entropy keeps increasing), so that raises the issue of how could it keep going forever. We sort of get stuck with choosing among thinking that it must somehow recycle or end, without any third option we can conveniently think of. I suppose we can sort of consider that it could change forever into an infinite number of different forms without ever repeating, but that is really just the no-end with infinite changes over infinite time subset of no-end.

I can understand that some people want to think that absolute knowledge of all physical laws and the detailed states of every bit of matter and energy at a single point in time could theoretically allow an absolutely accurate prediction of the future. In that sense, "predetermined" seems at least theoretically logical. However, it is also impossible as a practical matter, to have such detailed knowledge of the present, and not just for us mere mortals. The Heisenberg Uncertainty principle would seem to indicate that such detailed knowledge is not even possible.

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[COLGeek]

Please don't bring religion into the discussion. That never ends well. Thanks.

 

[Unclear Engineer]

Please don't bring religion into the discussion. That never ends well. Thanks.

OK, I did not think what I wrote was introducing religious issues. I was only mentioning a logical conundrum with the definition of "universe" and "beginning".

Please carry on as if I never posted, and I will try to be more careful, here

 

[Catastrophe]

I wish to apologise for starting a thread which might raise certain areas that we all agree not to discuss here. This was certainly not my intention.

Let me please lead us away from any resultant difficulty. The block model leads, imho, to a logical impossibility in that it is ridiculous to suggest that every particle in the Universe has a world line which is fixed by Physics or anything else. As Unclear Engineer correctly points out, this is forbidden by the Heisenberg Uncertainty Principle for starters.

This whole idea was cleared up decades ago when Laplace's idea was overthrown by Quantum Mechanics and the Heisenberg Uncertainty Principle.

QUOTE
"In the history of science, Laplace's demon was a notable published articulation of causal determinism on a scientific basis by Pierre-Simon Laplace in 1814.[1] According to determinism, if someone (the demon) knows the precise location and momentum of every atom in the universe, their past and future values for any given time are entailed; they can be calculated from the laws of classical mechanics.[2]"
Quote

Sourse: Laplace's demon - Wikipedia

Taking away this unacceptable consequence of the BLOCK model, what is its position?

If we take the scientific view of world lines, these simply represent the actual historical representation of what has already taken place, without any Laplacian implications. They include quantum 'options' which have already taken place, without any suggestions of future prediction, which is the province of quantum effects.

So our world lines (and the worldlines of every particle) simply represent the history of the Universe (but in totally unknowable detail when it comes to every elementary particle).

The next idea to be considered is that the worldline of our past experience certainly contains a succession of 'real' moments. These are accessible as 'memories', but it is a matter of experience that we are unable to access the 'moment' itself, reproducing the same degree of 'reality'.

So we are left with the idea that the worldline contains an interface, in accordance with our experience, which is the present moment, the 'travelling now'. Does it help us in any way to consider worldlines in a spacetime block model of the Universe? That is more a question for metaphysics or philosophy, so we are unlikely to provide answers here, unless we can introduce some form of scientific experiment which provide reproducible results.

Cat

 

[Catastrophe]

Perhaps this represents a reasonable modification to the block model.

That Mysterious Flow

From the fixed past to the tangible present to the undecided future, it feels as though time flows inexorably on. But that is an illusion

www.scientificamerican.com

Sorry, I have been having trouble getting this link to function, but you can read it using your slider on the right and 'down' arrow.


Cat