The Multiverse.

Max Erik Tegmark (born 5 May 1967) is a Swedish-American physicist, cosmologist and machine learning researcher. He is a professor at the Massachusetts Institute of Technology and the president of the Future of Life Institute. He is also a scientific director at the Foundational Questions Institute, a supporter of the effective altruism movement, and has received research grants from Elon Musk to investigate existential risk from advanced artificial intelligence.

https://en.wikipedia.org/wiki/Max_Tegmark

He is an advocate of the Multiverse theory which he arrived at by using mathematics.

The mathematics of Multiverse theory suggests that our universe, with all its hundreds of billions of galaxies and almost countless stars, spanning tens of billions of light-years, may not be the only one. Instead, there may be an entirely different universe, distantly separated from ours — and another, and another. Indeed, there may be an infinity of universes, all with their own laws of physics, their own collections of stars and galaxies (if stars and galaxies can exist in those universes), and maybe even their own intelligent civilizations.

It could be that our universe is just one member of a much grander, much larger multitude of universes: a multiverse.

The concept of the multiverse arises in a few areas of physics (and philosophy), but the most prominent example comes from something called inflation theory. Inflation theory describes a hypothetical event that occurred when our universe was very young — less than a second old. In an incredibly brief amount of time, the universe underwent a period of rapid expansion, "inflating" to become many orders of magnitude larger than its previous size, according to NASA.

Inflation of our universe is thought to have ended about 14 billion years ago, said Heling Deng, a cosmologist at Arizona State University and an expert in multiverse theory. "However, inflation does not end everywhere at the same time," Deng told Live Science in an email. "It is possible that as inflation ends in some region, it continues in others."

Thus, while inflation ended in our universe, there may have been other, much more distant regions where inflation continued — and continues even today. Individual universes can "pinch off" of larger inflating, expanding universes, creating an infinite sea of eternal inflation, filled with numerous individual universes.

In this eternal inflation scenario, each universe would emerge with its own laws of physics, its own collection of particles, its own arrangement of forces and its own values of fundamental constants. This might explain why our universe has the properties it does — particularly the properties that are hard to explain with fundamental physics, such as dark matter or the cosmological constant, Deng said. 

"If there is a multiverse, then we would have random cosmological constants in different universes, and it is simply a coincidence that the one we have in our universe takes the value that we observed," he said.

Perhaps the most mind-bending implication of the multiverse is the existence of doppelgängers. If there really are an infinity of universes but a finite number of ways to arrange particles in any individual universe, then the same patterns are bound to be repeated, eventually. That would mean that at some incredible (but finite!) distance, there would be an exact copy of you reading an exact copy of this article. And because there would be an infinite number of universes, there would be an infinite number of these exact scenarios all happening simultaneously, according to the Institute of Physics.

https://www.livescience.com/multiverse

This is a quote from a lecture given by Max Tegmark.

"When we say the our observable universe or just our universe for short, we don’t mean all of space we mean the region of space from which life has attempted to reach us during the thirty billion light years since the big bang. We humans have again and again made this mistake of thinking that everything that we knew about was everything that existed. But that was just a small part of a much grander structure: a planet, a solar system, a galaxy. The most popular theory we have called 'inflation' actually predicts that the simplest versions of space go on forever, and if that's true, then you can fit infinitely many other universe sized regions into this."

The mathematics of inflation predicts a multiverse where every possible history of the universe exists as an expanding 'Hubble Volume'.

In cosmology, a Hubble volume (named for the astronomer Edwin Hubble) or Hubble sphere, subluminal sphere, causal sphere and sphere of causality is a spherical region of the observable universe surrounding an observer beyond which objects recede from that observer at a rate greater than the speed of light due to the expansion of the Universe.

In simple terms, it is what we can observe by looking outwards into the 'universe'.

In the mathematics of the 'Eternal Inflation Theory', the multiverse, or space as a whole, is stretching and will continue to do so forever. But some regions of space stopped stretching and formed distinct bubbles; like gas pockets in a loaf of rising bread. This gives rise to the idea that in each bubble, the laws of physics, the mathematical constants are different.

So let us pause for breath and simplify the data.

Mathematics allegedly supports the idea that there are many universes (multiverses), not just one.

The entire structure of multiverses is forever expanding except for pockets here and there which ceased to expand. 

In each of these pockets, the laws of physics and mathematical constants are different.

In the multiverse every possibility will be expressed and multiple copies of the same thing can occur; imagine multiple copies of you leading the exact same life!

Does this sound rational?

This is a quote from Dr. Stuart Clark, astronomer and author of "The Unknown Universe."

"The multiverse is something that has come at astronomers and physicists from a number of different angles. It seems that there are a number of problems in physics and astronomy that could be solved if there were, not just this universe, but an infinite number of other universes. So one of those things is whenever a quantum particle changes its state, there's nothing in our laws of physics that direct it to change that state in one particular way or another. So how does it choose to do that? Well, if there's a multiverse then every possibility is played out. So it becomes understandable in that way. And also when astronomers look out into space they see as far as they possibly can but what's beyond that? Are there other realms out there as well, other universes? then when we start to get into the  theories to join our understanding of gravity with the understanding of the other forces of nature, then we'reled to things like string theory and they postulate different dimensions of existence. Agaian, natural places to find other universes, And so in all these different ways there could be multiple universes. If every possibility is played out across this huge multiverse, well it makes our universe just a sheer accident.

I think for me I would prefer it if there wasn't a multiverse. If the universe that we see around us today is all that there actually is and that spurs us on to find the meaning in the laws of physics; the reason why the universe is just this way and no different. But of course the universe doesn't care what I think or want. It will just do what it does.

So we are all just obedient, subservient pawns in a giant game of 'cosmic chess'.

This is nihilism on a grand scale!

https://www.bing.com/videos/search?q=the+multiverse+theories&view=detail&mid=74B3188283BA5A1FF9A274B3188283BA5A1FF9A2&FORM=VIRE

Mathematical Set Theory.

In mathematical set theory, the multiverse view proposes that there are many models of set theory, but no "absolute", "canonical" or "true" model. Each of the multiverses has its own ideas of what is true. and the various models are all equally valid or true, though some may be more useful or attractive than others. The opposite view is the "universe" view of set theory in which all sets are contained in some single ultimate model.

https://en.wikipedia.org/wiki/Multiverse_(set_theory)

The multiverse model is pure relativism, where there is no absolute truth, but every opinion and possibility no matter how ridiculous or insane, is taken as being true. It totally violates the Principle of Sufficient Reason and is a completely false proposition. 

Looking for dead cats, or The Many Worlds Interpretation.

Erwin Rudolf Josef Alexander Schrödinger 12 August 1887 – 4 January 1961), was a Nobel Prize-winning Austrian-Irish physicist who developed a number of fundamental results in quantum theory: the Schrödinger equation provides a way to calculate the wave function of a system and how it changes dynamically in time.

The wave function describes where something is and what it is doing; but it only provides statistical probabilities and not a definite answer.

https://en.wikipedia.org/wiki/Erwin_Schr%C3%B6dinger

As Schrödinger used to point out to anyone who would listen, there is nothing in the equations (including his famous wave equation) about collapse. That was something that Niels Bohr bolted on to the theory to “explain” why we only see one outcome of an experiment — a dead cat or a live cat — not a mixture, a superposition of states. But because we only detect one outcome — one solution to the wave function — that need not mean that the alternative solutions do not exist. In a paper he published in 1952, Schrödinger pointed out the ridiculousness of expecting a quantum superposition to collapse just because we look at it. It was, he wrote, “patently absurd” that the wave function should “be controlled in two entirely different ways, at times by the wave equation, but occasionally by direct interference of the observer, not controlled by the wave equation.”

In 1952 he gave a talk in Dublin, where he stressed that when his 'wave function' equation seems to describe different possibilities, they are not alternatives but all really happen simultaneously, 

Hugh Everett III (November 11, 1930 – July 19, 1982) was an American physicist who first proposed the many-worlds interpretation (MWI) of quantum physics, which he termed his "relative state" formulation. In contrast to the then-dominant Copenhagen interpretation, the MWI posits that the wave function never collapses and that all possibilities of a quantum superposition are objectively real.

https://thereader.mitpress.mit.edu/the-many-worlds-theory/

Imagine you are walking home in the dark and you dropped your house keys down a hole in the ground, but because there are two holes next to each other, you don't know which one has your keys. Let's name the holes A and B. 

In possibility one you find the keys in hole A but not hole B.

In possibility two you find the keys in hole B but not hole A.

These two possibilities exist simultaneously and are both objectively real, so this means that if you look into hole A and find the keys, another version of you will look into hole B and find the keys.

So the question is: "Where is free will if the outcomes of the two possibilities are both objectively real and therefore already determined?"

Relativity Theory

The mathematics behind Relativity Theory states that everything is subjective and there is no objective reality. Each observer is locked inside their inertial frame; and this doesn't just apply to living forms, it applies to all forms. Everyone has the right answer and there is no absolute.

"Since there exists in this four dimensional structure [space-time] no longer any sections which represent "now" objectively, the concepts of happening and becoming are indeed not completely suspended, but yet complicated. It appears therefore more natural to think of physical reality as a four dimensional existence, instead of, as hitherto, the evolution of a three dimensional existence."

Albert Einstein.

The theory relies on what is termed 'block time' and this has been used to propose that time travel is possible.

In 'block time' every possible outcome has already been fully realised and this means that there are no future unknowns. 

There is no free will either.

So what's the point?

To reiterate:

The multiverse model is pure relativism, where there is no absolute truth, but every opinion and possibility no matter how ridiculous or insane, is taken as being true. 

It totally violates the Principle of Sufficient Reason and is a completely false proposition.