Block Universe

[steve_bank]

Pood periodically brings it up so I looked at it.

Time is clicks on a clock. Time has no more relity than mters and kilograms.

Time is a quantifiable measurement of rate of change. Instead of time say rate of change.

The universe changes, we measure in seconds and meters.

Perception of passage of time on a clock or passage opf Moon is subjective.

The four dimensional block is just space-time, (x,y,z,t).

Observed charge is not an illusion neither is time in seconds..

Sounds like he philosophized on AE.

AI Overview
Einstein's block universe fact or fiction | Unifying Quantum ...
The "block universe" is a philosophical model where all of time—past, present, and future—exists equally and is equally real, much like all of space exists. In this model, the universe is seen as a four-dimensional "block" of spacetime, and the passage of time is an illusion of human perception. This concept is often associated with Einstein's theory of relativity, where time and space are fused into a single fabric.
Core principles

All time exists: The past, present, and future are all equally "there." Your birth and your death are both just events located at specific coordinates in this four-dimensional block.
No privileged "now": The idea of a universal "now" is dismissed because simultaneity is relative, meaning what is "present" for one observer can be in the past or future for another.
Determinism: The future is just as fixed as the past, meaning that if the theory holds, everything that will ever happen is already part of this block.
Illusion of passage: The feeling of time moving is considered a subjective human experience, not an objective property of the universe. Think of it like a movie: the entire film exists on the DVD, but the characters within the film are not aware of the ending.

Growing block universe - Wikipedia

en.wikipedia.org

The growing block universe, or the growing block view, is a theory of time arguing that the past and present both exist, while the future does not yet exist. The present is the perpetuating factor of time, where new moments are added to the past. By the passage of time more of the world comes into being; therefore, the block universe is said to be growing. The growth of the block is supposed to happen in the present, a very thin slice of spacetime, where more of spacetime is continually coming into being. Growing block theory should not be confused with block universe theory, also known as eternalism.

The growing block view is an alternative to both eternalism (according to which past, present, and future all exist) and presentism (according to which only the present exists). It is held to be closer to common-sense intuitions than the alternatives. C. D. Broad was a proponent of the theory (1923). Some modern defenders are Michael Tooley (in 1997) and Peter Forrest (in 2004). Fabrice Correia and Sven Rosenkranz (2015) have developed their own distinctive view of this theory.[clarification needed]

Broad first proposed the theory in 1923. He described the theory as follows:

‘It will be observed that such a theory as this accepts the reality of the present and the past, but holds that the future is simply nothing at all. Nothing has happened to the present by becoming past except that fresh slices of existence have been added to the total history of the world. The past is thus as real as the present. On the other hand, the essence of a present event is, not that it precedes future events, but that there is quite literally nothing to which it has the relation of precedence. The sum total of existence is always increasing, and it is this which gives the time-series a sense as well as an order. A moment t is later than a moment t' if the sum total of existence at t includes the sum total of existence at t' together with something more.[1]’

 

[pood]

The growing block view is incoherent,

The issue is between eternalism and presentism.

Einstein initially rejected the block world and then embraced it.

 

[steve_bank]

Don't know much about the philosophies of AE, bty form his bio he was eccentric.

Eternalism (philosophy of time) - Wikipedia

en.wikipedia.org

In the philosophy of space and time, eternalism[1] is an approach to the ontological nature of time, which takes the view that all existence in time is equally real, as opposed to presentism or the growing block universe theory of time, in which at least the future is not the same as any other time.[2] Some forms of eternalism give time a similar ontology to that of space, as a dimension, with different times being as real as different places, and future events are "already there" in the same sense other places are already there, and that there is no objective flow of time.[3]

It is sometimes referred to as the "block time" or "block universe" theory due to its description of space-time as an unchanging four-dimensional "block", as opposed to the view of the world as a three-dimensional space modulated by the passage of time.

Presentism has two main meanings: in philosophy, it is the belief that only the present moment is real; in social sciences and history, it is the practice of interpreting past events through the lens of modern values and perspectives. The philosophical view holds that past and future entities do not exist, while the historical view argues that applying current knowledge to judge historical figures is anachronistic and can lead to misinterpretation.

Philosophical presentism - Wikipedia

en.wikipedia.org

Presentism (sometimes 'philosophical presentism') is the view of time which states that only present entities exist (or, equivalently, that everything which is exists presently) and what is present (i.e., what exists) changes as time passes.[1] According to presentism, there are no past or future entities at all, though some entities have existed and other entities will exist. In a sense, the past and the future do not exist for presentists—past events have happened (have existed, or have been present) and future events will happen (will exist, or will be present), but neither exist at all since they do not exist now. Presentism is a view about temporal ontology, i.e., a view about what exists in time, that contrasts with eternalism—the view that past, present and future entities exist (that is, the ontological thesis of the 'block universe')—and with no-futurism—the view that only past and present entities exist (that is, the ontological thesis of the 'growing block universe').[2]

To e the debate seems a little silly.

The universe exists and we observe consonant change.

Mathematically you could say the present is the limit as dt-->0. The change of the posit Ion of the Moon can not go to zero.

The present is a narrow moving window. In electronics the window can be pico seconds. In politics the present can be hours, days, or weeks.

 

[bilby]

We had a whole thread on this topic a couple of years ago.

Time is clicks on a clock. Time has no more relity than mters and kilograms.

And no less. Metres and kilograms are real. But they are (like seconds) not absolute - they depend on the relative motions of the observer and that which he observes.

That's the entire point of Einstein's theory.

Time is a quantifiable measurement of rate of change. Instead of time say rate of change.

In a single reference frame, sure. But stuff in the real universe moves relative to other stuff, and moving clocks do not measure the same rate of change as stationary clocks.

And that's not just some esoteric theory; GPS has to take this into account in order to work, so it's a practical and measurable effect which you likely depend upon yourself in your daily life - or at least, any time you go someplace new.

So, yes, the four dimensional block is "just" spacetime, but it's not a purely philosophical conjecture. The clear implication of Einsteinian Relativity is that observers moving relative to each other can disagree, not only about the rate at which time passes, but even about the order in which events happen.

Objects with zero rest mass (such as photons) move through spacetime such that their speed is c for all observers, no matter how those observers move.

This strongly suggests that the concept of "now" is entirely personal, and that there is no "the present", but rather a different present for each reference frame; The surviving Apollo astronauts are living a few nanoseconds behind the rest of us, as a consequence of their journey to the Moon.

This effect is also expermentally demonstrated at CERN and by other particle accelerators. When short-lived particles are produced that are travelling at high speed, their half-life is measurably longer - by exactly the amount that is predicted if we calculate how much more slowly they are moving along the time axis.

Minkowski Spacetime is a four dimensional structure. If you visit a point (x, y, z, t), you always arrive at the same thing. This is uncontroversial for t<now, which we call "the past"; If you go to 32°46′43″N 96°48′31″W 1963/11/22 06:30Z, you will find an assassination in progress - that event is fixed in that space and time, and cannot be altered - it's a thing that happened.

The idea that going to coordinates (x, y, z, t) might get you to different events on different trips (perhaps by different observers) seems absurd - that you could go to Dealey Plaza, Dallas, TX, on the afternoon of November 22nd, 1963, and find that JFK just drove through in his motorcade without incident, is obviously wrong.

All that the "block universe" concept does is to say that, as time is not absolute, nor agreed upon by observers in different reference frames, there is no way to mathematically nor physically separate "past" from "future". So we should assume that going to coordinates (x, y, z, t) gets you to the same event that anyone going to those coordinates gets to. Even if t>now. That is, the future is no more changeable than is the past.

We can't see the future, except by actually going there; But then, I can't see Seattle from my physical location, but that doesn't justify my assuming that it doesn't exist. I am confident that if I went to 47°36'28.8468"N 122°20'6.6012"W, I wouldn't find myself in New York or Moscow, and nor would anyone else.

I am equally confident that if I was there at noon yesterday, I would see the same stuff happening that everyone else in that place and time would see; And that if I am there at noon tomorrow, I will also see the same stuff happening that everyone else in that place and time would see.

Change over time isn't possible for a four dimensional view of spacetime. It's only possible in three dimensional space, because we have a fourth dimension (time) against which to measure it. The rate at which our personal "now" travels through time seems to be constant - but in fact it is not. We just don't often accelerate enough to notice that it changes.

x, y, z, t is sufficient to define a single, fixed, event. The matrix of all values of x, y, z, and t is Minkowski Block Spacetime. To suggest that it doesn't exist seems absurd to me - are you claiming that coordinate systems don't explicitly define the points within them? Or are you just refusing to consider the physical and mathematical consequences of the fact they do?

 

[pood]

Presentism holds that only the present is real. Eternalism holds that all moments in time exist in the same way that all locations in space do.

In can be cashed out in terms of McTaggert’s A and B theory of time. The A theory holds that time somehow “flows” from past to present to future, with only the present being real. It is a tensed theory. The B theory is tenseless, holding that all moments in time exist in an earlier than/later than set of relations. On this account dinosaurs exist earlier than humans, in the same way that San Francisco exists west of New York. But both the dinosaurs and San Francisco exist no less than humans and New York City.

You could say, “Socrates exists,” only he is distant from me in time, in the same way you would say “Jupiter exists,” but is distant from me in space.

Events, entities and objects, “later than” what we call “now” obviously must also exist on this account. It’s a kind of spatializing of time.

Relativity theory strongly supports the B theory. Hence the block universe. Relative simultaneity cannot exist under the A theory.

 

[pood]

Under eternalism we have temporal parts in the same way we have spatial parts. The “I” writing this at the moment is nowhere near the whole of me, but a cross section, or foliation, of my world line in block world,

 

[pood]

Consider Einstein’s original thought experiment of a train racing down the track.

There is a rider equidistant between the back and front of the train.

There is an observer on the ground.

Now imagine that the rider on the train and the observer on the ground are exactly aligned. Their eyes lock.

Two lightning flashes go off.

One hits the back of the train and one hits the front of it.

The observer on the ground judges the flashes to strike simultaneously,

But the observer on the train judges the front flash to hit before the rear flash, because light does not obey Galilean additivity.

Therefore for the ground observer, the rear flash is in his PRESENT, whereas for the train observer, it lies in his FUTURE. He does not know this future, but he cannot avoid it. It is fixed!

You could have a second train going in the opposite direction. For an observer on that train, the rear flash on the other train strikes first, and the flash in front strikes later.

What should we conclude from this?

Presentism holds that the present moment, to borrow technical jargon, quantifies over a unique set of entities, objects and events that are the same for all observers.

The relativistic train thought experiment invalidates this.

It seems past, present and future are co-equal and eternalism or block world is true.

Imagine a loaf of bread cut at three different angles. For those metaphorically inside these cross sections or foliations, they would imagine that their experience is all there is to the bread. They don’t realize a whole other bunch of bread exists independent of their parochial experience.

 

[steve_bank]

That thought experiment is a consequence of the finite speed of light and the fact C is constant in all frames regardless of relative velocity.

The other part of the train experiment is someone on the train traveling at constant velocity dropping a ball. To the observer on the train the ball falls straight down. To an observer on the ground the ball has a parabolic trajectory.

Neither time, mass, or distance are 'real' in a material sense. You can not get a bucket of seconds, kilograms, or meters.

I can get a bag of apples that has mass of 1kg. I can measure the distance between two points in meters, measure the time its takes to cross the distance, and calculate velocity in meters/seconds.

Meters, seconds, and kilograms are all called dimensions. Due mostly to scifi the word time can invoke a kind of spookiness.
Functionally there is no difference between the atomic clock standard of today, and the sand and water clocks of the past.

In philosophy, time is defined in various ways, including as a measurement of change and motion (Aristotle), an independent absolute (Newton), or a mental construct our minds use to organize experience (Kant). Philosophers have debated whether time exists independently of consciousness or is a product of the mind, and some consider it to be a single, unified concept of past, present, and future rather than a linear progression.

All the positions of the Moon past, p[resent, and future exist simultaneously?

To me it is fiction until at least something like block universe can be expressed mathematically where mass and energy are accounted for.Metaphysics is a wa

Time as an independent reality was a recurring theme on Star Trek and other scifi.

In a STNG episode an experiment gone wrong is sending out waves of time displacement. At the end there is a series of Datas separated in time walking towards the experiment talking to each other as to who has to fix it. Entertaining fiction.


Metaphysics is attempt to describe reality without math and physics.

Metaphysics is a branch of philosophy that explores the fundamental nature of reality, existence, and being.
The word originated from the Greek words "meta" (beyond) and "physika" (physical), referring to the location of certain of Aristotle's works after his writings on physics. What was initially a label for his books came to signify the study of subjects that transcend the physical world, such as causality, consciousness, and ultimate reality.

 

[bilby]

Neither time, mass, or distance are 'real' in a material sense. You can not get a bucket of seconds, kilograms, or meters.

Nobody thinks that these things are material. But to suggest that they are therefore not real is myopic to the point of absurdity.

 

[bilby]

I can get a bag of apples that has mass of 1kg. I can measure the distance between two points in meters, measure the time its takes to cross the distance, and calculate velocity in meters/seconds.

In what reference frame? Different observers with different reference frames will get different answers for mass and for distance and for time.

 

[bilby]

To me it is fiction until at least something like block universe can be expressed mathematically where mass and energy are accounted for.

So, until 1905? Okay, if you like.

 

[pood]

Minkowski spacetime is a mathematical forumulation.

 

[pood]

Minkowski space

 

[steve_bank]

For shits and giggles.

Fundamental in science and engineering is dimensional analysis.

Seconds, kilograms, and meters are dimensions, units of eqasure. SI base units.

Velocity = meters/second

Force in Newtons = kilograms*meters/second^2

Dimensional analysis - Wikipedia

en.wikipedia.org

In engineering and science, dimensional analysis of different physical quantities is the analysis of their physical dimension or quantity dimension, defined as a mathematical expression identifying the powers of the base quantities involved (such as length, mass, time, etc.), and tracking these dimensions as calculations or comparisons are performed.[1] The concepts of dimensional analysis and quantity dimension were introduced by Joseph Fourier in 1822.[2]: 42 

Commensurable physical quantities have the same dimension and are of the same kind, so they can be directly compared to each other, even if they are expressed in differing units of measurement; e.g., metres and feet, grams and pounds, seconds and years. Incommensurable physical quantities have different dimensions, so can not be directly compared to each other, no matter what units they are expressed in, e.g. metres and grams, seconds and grams, metres and seconds. For example, asking whether a gram is larger than an hour is meaningless.

Any physically meaningful equation or inequality must have the same dimensions on its left and right sides, a property known as dimensional homogeneity. Checking for dimensional homogeneity is a common application of dimensional analysis, serving as a plausibility check on derived equations and computations. It also serves as a guide and constraint in deriving equations that may describe a physical system in the absence of a more rigorous derivation.

 

[steve_bank]

iMinkowsky space? Space-Time in the absence of gravity is (x,y,z,t).

If you are standing on the street in NYC the position of a building in your (x.y.z) does not change with time.

Relative to your ()x,y,z) coordinate system with you at (0,0,0) the position of the Moon changes with time. Hence space-time is (x,y.z,t)

Minkowski time loops are a theoretical concept suggesting the mathematical possibility of causal loops within flat spacetime, as described by Minkowski's model, without necessarily violating the principle that information cannot travel faster than light. While traditional physics assumes causal loops are impossible in Minkowski spacetime because they are a form of closed timelike curve, new models explore scenarios where such loops could exist if there is a "fine-tuned influence" that is not a standard signal. Researchers have shown that these loops could, in principle, be operationally verified without superluminal signaling.

Initially, Albert Einstein dismissed Hermann Minkowski's geometric formulation of spacetime as "superfluous learnedness". However, he never specifically commented on "Minkowski time loops" because such closed timelike curves (CTCs) are impossible in the flat, Minkowski spacetime of special relativity. The concept of CTCs only arises in the curved spacetime of Einstein's later theory, General Relativity, a field he could only explore thanks to Minkowski's foundational work.

Speculative. In every time travel and FTL scheme I looked at there was an impossibility in implementation.

My fall back response is that I can create electrical systems that are mathematically and dimensionally consistentt but can never be physically built.

 

[bilby]

In every time travel and FTL scheme I looked at there was an impossibility in implementation.

Meh. Nobody's suggesting FTL; And time travel is constant and unavoidable. You are moving at one second per second through time right now.

If you could stop time travelling, but still travel through space, then that would be FTL - which as you say, appears to be impossible to implement.

 

[bilby]

My fall back response is that

...every scientific theory that you don't understand can be dismissed as "Science Fiction", thereby absolving you of the painful process of thinking about stuff that might cause you to change your mind about something.

Or you post a high school level summary of dimensional analysis, with the apparent expectation that everyone here will be amazed at the novelty of the idea. Oddly, your granny isn't impressed by your tutorial on how to suck eggs.

 

[Swammerdami]

Presentism holds that only the present is real. Eternalism holds that all moments in time exist in the same way that all locations in space do.

In can be cashed out in terms of McTaggert’s A and B theory of time. The A theory holds that time somehow “flows” from past to present to future, with only the present being real. It is a tensed theory. The B theory is tenseless, holding that all moments in time exist in an earlier than/later than set of relations. On this account dinosaurs exist earlier than humans, in the same way that San Francisco exists west of New York. But both the dinosaurs and San Francisco exist no less than humans and New York City.

You could say, “Socrates exists,” only he is distant from me in time, in the same way you would say “Jupiter exists,” but is distant from me in space.

Events, entities and objects, “later than” what we call “now” obviously must also exist on this account. It’s a kind of spatializing of time.

Relativity theory strongly supports the B theory. Hence the block universe. Relative simultaneity cannot exist under the A theory.

The human brain distinguishes clearly among past. present and future and "sees" itself clearly following a temporal trajectory. This is just an artifact of closely correlated "time capsules" (cf Julian Barbour) as discussed here a year ago.

 

[aupmanyav]

Sort of like the growing block theory. It avoids determinism.
The problem is that the whole of it could be imaginary, perception, the universe and what happened in it. That is why one cannot get back to it, unless one goes in space at a speed greater than that of light, and observes the world from there. One would need a very strong telescope.

 

[Elixir]

unless one goes in space at a speed greater than that of light, and observes the world from there.

Nonsense. Greater than C relative to what?
If you recede from earth at >C (an impossibility in the first place) you cannot observe it.