Notes on Block Universe Theory

“There is not past, no future; everything flows in an eternal present.”

~ James Joyce

It's entirely possible that human perception of time is the result of evolution and nothing more.

The true reality of existence lies in the eternal “now.”

Under relativity, all times are equally real. Everything that has ever happened or ever will happen is happening now for a hypothetical observer. There are no events that are either merely potential or a mere memory. There is no single, absolute, universal present, and thus there is no flow of time as events supposedly “become” present.

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"Nothing occurs at random, but everything for a reason and by necessity."

Block Universe presents 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.

If the Past, Present, and Future all exist in exactly the same way, then every single moment would be a ‘Now’ moment for me.

It would also mean that me being dead in the future is equally real in the exact same way as me being alive right Now is real.

And since the Past is as real as the Present and future, me being alive in the Past is equally real as me being alive right Now.

It’s like a Möbius strip; it’s like the ouroboros eating its tail. All times are happening now.

I was born in 1963; let's suppose I die in 2063.

From a presentist point of view, I'm alive now, I've been alive since 1963, and I'll probably die sometime.

From an eternalist point of view, I'm an entity that exists from 1963 to 2063 within certain spatial boundaries.

Eternalism is a philosophical 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.[1] 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.[2] 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.

Predeterminism is the philosophy that all events of history, past, present and future, have been already decided or are already known, including human actions.

Predeterminism is the idea that all events are determined in advance.

It is information conserving.

The theory known as the ‘block universe’ states that the past, present and future already exist.

The concept of time is simply an illusion made up of human memories, everything that has ever been and ever will be is happening RIGHT NOW.

Time is simply human construct.

What we perceive as the past is simply an illusion formed in our brain.

The laws of physics are symmetric ultimately meaning that time could have easily moved in a backward direction as it does forward.

There is a ‘block-universe’ where time and space are connected, otherwise known as spacetime.

The theory, which is backed up Einstein’s theory of relativity, states that space and time are part of a four dimensional structure where everything thing that has happened or ever will happen has its own co-ordinates in spacetime.

When Einstein unified space and time in his general theory of relativity in 1915, he gave us a new way to picture our Universe.

Imagine a regular chunk of cement. It has three dimensions but we live in four dimensions: the three spatial dimensions plus one time dimension. A block universe is a four-dimensional block, but instead of being made of cement, it is made of spacetime. And all of the space and time of the Universe are there in that block.

In the growing-block universe theory every event past, and present are both ontologically equivalent; however, future events are not.

We can't see this block, we're not aware of it, as we live inside the cement of spacetime. And we don't know how big the block universe we live in is: "We don't know if space is infinite or not. Or time - we don't know whether it has a beginning or if it will have an end in the future. So we don't know if it's a finite chunk of spacetime or an infinite chunk.

The only evidence we have of the Earth's past is rocks and fossils. But these are just stable structures in the form of an arrangement of minerals we examine in the present.

The past, present and future are all happening simultaneously because there is only one moment in time that exists, has ever existed or will ever exist.

The name we have collectively agreed upon to give to that single moment is..."NOW".

So time is always relative to a starting point that we define as a beginning. We invent calendars and clocks to record the passage of time from the starting point, which is a collective arbitrary decision, and there can be no space without this arbitrary time that we invented.

Think about it. It takes time to travel the distance or space between A to B, but without time that space doesn’t exist, cannot exist. Thus, space and time are inseparable like two sides of the same coin; they’re a single unit of measurement.

So time and, by definition, space, are always relative and are both concepts that are created and used by our collective consciousness to navigate this 4 dimensional time-space reality called life on Earth.

Once we grasp this truth, we begin to remember and understand that the only real time is now and the only real place is here. Be Here now.

Our limited consciousness cannot by its very nature process this because we are not aware of any dimensions beyond the four which make up our “universe”. It we were able to look at our block universe from the “5th dimension”, from ‘above’, time would look like space looks to us today, spreading everywhere, encompassing all. We would see all of our past and all of our future simultaneously. If you look a little bit behind in the block you may see dinosaurs ruling the earth, look a little ahead and you see our future…all happening now….at the same time. You can see it all at the same time.

 A slice through the block of spacetime, corresponds to a specific time.

This seems surprising but is a straightforward consequence of general relativity being a deterministic theory.

General relativity says that if I know the conditions in this instant, I can predict the entire future because the laws of physics that govern this chunk of spacetime are deterministic.

The experiences you had a year ago or 10 years ago are still just as real, they’re just “inaccessible” because you are now in a different part of spacetime.

The future is entirely written, it's just not accessible to us inside the block at this point.

We’ll never really understand everything and definitely not from our limited physical human perspective, as everything ends up in paradox anyway.

For instance, while we perceive reality from our unique perspective, one of an infinite number of probable and possible Universal points of view; all realities must be happening now because chronological or linear time is a construct of this reality: it doesn’t exist independently.

It might come as a surprise that this orthodox “block universe” view of time in fact leads us to conclude that we possess a form of eternal life! This is a consequence of the principle that in the block time model all periods of time are equally real. If a loved one dies, you might take some comfort from the knowledge that this period of time in which your loved one is dead has, in fact, no greater reality than the time when your loved one was alive. According to physics, it is just as valid to consider your loved one as alive as it is to consider them dead!

Einstein took comfort from this knowledge when his lifelong friend Michele Besso died. He wrote a letter consoling Besso’s family: “Now he has departed from this strange world a little ahead of me. That means nothing. People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion.”

Of course, the flip-side is that you’re already dead!

The conclusions presented here relating to the block universe model follow directly from Einstein’s theory of general relativity and so should be considered to be orthodox physics.

It is meaningless to talk of the “start” of the universe, or the “emergence of the universe from nothing”, or any other term which implies change of the entire block universe structure over time. The entire spacetime block is laid out as one unchanging structure. Here’s a quote from Stephen Hawking’s book “A Brief History of Time”: “If the universe is really completely self-contained, having no boundary or edge, it would have neither beginning nor end: it would simply be.”

We “perceive” the universe to be expanding because our brains determine our feeling of directional time flow in the forward time direction. But that psychological arrow of time is always going to align itself from a low entropy universe state to a high entropy universe state.

That is no basis to say “the universe is expanding” – that just says something about the distribution of entropy in the entire universe structure. It is more accurate to say the universe is neither expanding nor contracting. It just has a structure. It just is.

The block universe model provides a solution to the grandfather paradox. According to the block universe model, all of space and time is laid-out in an unchanging spacetime block.

There can be no place for an oscillatory grandfather: the grandfather must be defined as being in an unchanging state of either dead or alive. It can never be possible to change that state. The only possible time loops would be consistent time loops.

The Wheeler-DeWitt equation agrees with our earlier analysis of the nature of time because it suggests a block universe model in which all of time is laid-out (just as the space dimension is laid-out), and all times are equally real: there is no special “now”, no distinction between past and future. In fact, “past” and “present” do not exist – the movement of time is considered to be just an illusion of human perception.

If someone a million light years away a million years from now looks at earth with a extremely good telescope. They would see you walking around doing your business. In this small way you are immortal.

The block universe is completely compatible with the notion of free will.

Free will is defined as the ability to make decisions.

EVENT 1) You walk along the road and come to a fork in the road.

EVENT 2) You decide to turn to the left.

EVENT 3) You continue your journey along the left road.

This is just a sequence of three events, and that’s all the block universe is: a sequence of successive events. So these three events can easily be incorporated into the block universe model.

In the block universe model, events are unchanging and “frozen-in-time”. But that does not mean that those events do not represent the expression of free will. For example, when we look back into the past we consider those past events to be “frozen”, and nothing could change those events. However, we might also remember some of those past events as representing moments when we made decisions, i.e., expressed our free will.

So the notion of free will is in no way incompatible with the block universe “frozen-in-time” representation of unalterable events.

As each decision can only ever have one outcome, no branching “multiverses” are necessary.

That may take a chunk of, well, time to digest.

The Block Universe of Special Relativity

But by treating the past, present, and future as materially identical, the theory is consistent with the laws of physics as we understand them.