The Multiversians are at the gates

[marcus]

The Multiversans are at the gates!

Remember the 2008 annual conference "Strings 2008" at Geneva, when the organizers excluded all "anthropic string landscape" and "multiverse" talks from being presented?

And the November 2008 workshop at Princeton (Steinhardt, Arkani-Hamed, Banks...) that pretty much concluded the landscape fad (2003-2007?) was finished?
http://www.math.columbia.edu/~woit/wordpress/?p=1285

Try to stop Multiverse at a professional academic level and it just flows around you into the gullible public media--maybe it is just too tempting a way to sell books!

Hawking's book "The Grand Design" is #1 seller today among all Amazon books. It goes on sale 7 September.
https://www.amazon.com/dp/0553805371/?tag=pfamazon01-20

Brian Greene's new title is scheduled to appear in January 2011 "The Hidden Reality--Parallel Universes and the Deep Laws of the Cosmos"
https://www.amazon.com/dp/0307265633/?tag=pfamazon01-20

So maybe we should talk about Multiverse thinking. What is it grounded in? Is there a basic scientific motivation for it?

 

[marcus]

Here's what Hawking is quoted as saying as blurb for the new book:

Stephen Hawking on The Grand Design


How can we understand the world in which we find ourselves? Over twenty years ago I wrote A Brief History of Time, to try to explain where the universe came from, and where it is going. But that book left some important questions unanswered. Why is there a universe--why is there something rather than nothing? Why do we exist? Why are the laws of nature what they are? Did the universe need a designer and creator?

It was Einstein’s dream to discover the grand design of the universe, a single theory that explains everything. However, physicists in Einstein’s day hadn’t made enough progress in understanding the forces of nature for that to be a realistic goal. And by the time I had begun writing A Brief History of Time, there were still several key advances that had not yet been made that would prevent us from fulfilling Einstein’s dream. But in recent years the development of M-theory, the top-down approach to cosmology, and new observations such as those made by satellites like NASA’s COBE and WMAP, have brought us closer than ever to that single theory, and to being able to answer those deepest of questions. And so Leonard Mlodinow and I set out to write a sequel to A Brief History of Time to attempt to answer the Ultimate Question of Life, the Universe and Everything. The result is The Grand Design, the product of our four-year effort.

In The Grand Design we explain why, according to quantum theory, the cosmos does not have just a single existence, or history, but rather that every possible history of the universe exists simultaneously. We question the conventional concept of reality, posing instead a "model-dependent" theory of reality. We discuss how the laws of our particular universe are extraordinarily finely tuned so as to allow for our existence, and show why quantum theory predicts the multiverse--the idea that ours is just one of many universes that appeared spontaneously out of nothing, each with different laws of nature. And we assess M-Theory, an explanation of the laws governing the multiverse, and the only viable candidate for a complete "theory of everything." As we promise in our opening chapter, unlike the answer to the Ultimate Question of Life given in the Hitchhiker’s Guide to the Galaxy, the answer we provide in The Grand Design is not, simply, "42."

 

[Dmitry67]

So Hawking believes in MWI (besides the Multiverse)
Cool!

 

[atyy]

So Hawking believes in MWI (besides the Multiverse)
Cool!

Hmmm, the quote sounds more like he believes in the multiverse instead of MWI!

Anyway, MWI is no longer MWI is it? It's just no collapse of the wave function, which is common to MWI and Bohmians, unified under decoherence, isn't it?

 

[marcus]

If an author is vague enough and talks about both MWI and bubble inflation multi in the same chapter, an average reader is probably not going to care about the difference.

John Gribbin got in early on this. His book came out in September 2009 and is doing quite well, Amazon salesrank around 1100 when I looked today. The title of Gribbin's is:
"In Search of the Multiverse: Parallel Worlds, Hidden Dimensions, and the Ultimate Quest for the Frontiers of Reality"
For comparison here is Greene's title:
"The Hidden Reality--Parallel Universes and the Deep Laws of the Cosmos"

Greene's title recycles buzzers from Gribbin's title: "hidden", "parallel", "reality".
Here's the page for Gribbin's
https://www.amazon.com/dp/0470613521/?tag=pfamazon01-20

 

[marcus]

Here's my personal view of these developments. Maybe you'd like to disagree.
What strikes me about most Multiverse stuff I hear is its uselessness as science.

Maybe this is obvious and hardly needs to be said (if not please tell me):
Science is about observing modeling predicting this universe.

Indeed to get a good model in cosmology you DO make it extend beyond what we can hope to observe---in a 'more of the same' fashion. That is an OCCAM assumption because it is simpler than postulating some kind of boundary with different stuff out beyond.
The portion of the universe that we do see behaves as if it were a part of a more or less uniform whole and it's simplest to understand and model that way.

So science is about observing modeling predicting this universe (even though we maybe can't observe everything or predict everything.)

As Niels Bohr put it, the subject of [micro-scale] physics is not what nature IS, but what we can say SAY about it. Fundamental physics aims to understand at a microscopic level not what the world is made of, but how it responds to measurement.

As Francis Bacon taught us in early 1600s, people shouldn't present us with theories that don't predict observable stuff. Theories should be empirical. That's the 400 year tradition of empirical science.

It doesn't matter if the model is made of tinkertoy or erector-set or lego-blocks as long as it works. There can even be two equally good models. But they have to work, and tell us correct numbers---that fit what happens in this universe.

Multiverse appears to be a fantasy---perhaps concocted to provide something for M-theory to rule over. Because M-theory (so far an unformulated, non-existent theory) has been unable to lock into this universe we live in but seems to lead to jillions of different versions of physics.

Multiverse also appears to be a cop-out: getting off the hook of not providing an explanation for the big bang. Personally I expect that an explanation of what led up to bang will eventually be worked out and will make testable predictions that one can check against ancient light. But in the meantime some people prefer to give up on that and say the universe just happened because of "quantum uncertainty". This sterile idea leads to no predictions of observable phenomena. But it does lead to the imaginative vision of a vast array of bubble universes--because if one can spring into existence why not jillions?--and that splendid imagery can boost booksales and ratings.

 

[marcus]

Sean Carroll has posted a 3-minute talking head video of his own titled
Stephen Hawking Settles the God Question Once and For All
http://blogs.discovermagazine.com/c...ng-settles-the-god-question-once-and-for-all/

Here's a quote from Nima Arkani-Hamed which I think is more sensible than any of this Multiverse buzz:

==quote==
Finally, Arkani-Hamed ended with the statement that string theory is useful as a way to study questions about quantum gravity, but “unlikely to tell us anything about particle physics”.
==endquote==

This was from Woit's report on the November 2008 symposium at Princeton on the string theory landscape. I gave the link in post #1 of this thread. If string, or M, is unlikely to tell us anything about particle physics this is presumably because it generates a vast landscape of possible versions of physics.
In that case, one can start exploring other theories that will hopefully be more narrowly selective (Steven Weinberg, Alain Connes, Roberto Percacci, Hermann Nicolai have indicated at various times they have ideas.)
Or does one cling to string and say that the world "really" consists of the huge landscape of versions that string predicts, rather than the one we know?

And then, to make that idea more exciting, does one spice it up with the God/non-God issue? This seems like plain old hokum either on Hawking's part or on that of his interpreters. Why not forget about such big issues and just get to work on better/more selective explanations of the world we observe?

Here's a 3 minute BBC news clip on Youtube with Hawking reading a short passage from his book, and some commentary

Here is a 10 minute BBC Youtube with more commentary, a bit bland and long.
Stephen Hawking: Physics leaves no room for God

 

[Amacha]

MultiVerse Theory makes String Theory look like Real Science.

From what I can tell new universe is created for every possible outcome. Let's take one gram molecular Weight of Uranium for instance. At any instant any of those 6.02 e 23 atoms could decay. So we would need 6.02 e 23 univeses EACH INSTANT to account for each of these outcomes. And each one of those univeses would need 6.02 e 23 universes each instant to account for the uranium in each of those universes. Of course any atom in the univese could suffer neutron decay at any instant, so we now need a new universe every instant for every atom in the universe. All of this created from nothing.

Or maybe its just things that are measured. So we take the same lump of uranium and as soon as we hold a geiger counter near it it starts creating universes from nothing.

Need I say that this is silly.

Personally, I would propose that if we don't need a creator for the universe, maybe we need an observer to collapse the wave forms, so that Sroendingers cat is really is alive or dead, becasue the unniversal observer can see it even if we can't.

 

[Kevin_Axion]

MultiVerse Theory makes String Theory look like Real Science.

From what I can tell new universe is created for every possible outcome. Let's take one gram molecular Weight of Uranium for instance. At any instant any of those 6.02 e 23 atoms could decay. So we would need 6.02 e 23 univeses EACH INSTANT to account for each of these outcomes. And each one of those univeses would need 6.02 e 23 universes each instant to account for the uranium in each of those universes. Of course any atom in the univese could suffer neutron decay at any instant, so we now need a new universe every instant for every atom in the universe. All of this created from nothing.

Or maybe its just things that are measured. So we take the same lump of uranium and as soon as we hold a geiger counter near it it starts creating universes from nothing.

Need I say that this is silly.

Personally, I would propose that if we don't need a creator for the universe, maybe we need an observer to collapse the wave forms, so that Sroendingers cat is really is alive or dead, becasue the unniversal observer can see it even if we can't.

Your argument derives from philosophy not science and String Theory in itself is greatly incomplete and only brushes what is science in the context of Multiverse.

 

[oldman]

...What strikes me about most Multiverse stuff I hear is its uselessness as science...Science is about observing modeling predicting ...this universe (even though we maybe can't observe everything or predict everything.)

...the subject of [micro-scale] physics is not what nature IS, but what we can say SAY about it. Fundamental physics aims to understand at a microscopic level not what the world is made of, but how it responds to measurement.

As Francis Bacon taught us in early 1600s, people shouldn't present us with theories that don't predict observable stuff. Theories should be empirical. That's the 400 year tradition of empirical science.

It doesn't matter if the model is made of tinkertoy or erector-set or lego-blocks as long as it works. There can even be two equally good models. But they have to work, and tell us correct numbers---that fit what happens in this universe.

Multiverse appears to be a fantasy---perhaps concocted to provide something for M-theory to rule over. Because M-theory (so far an unformulated, non-existent theory) has been unable to lock into this universe we live in but seems to lead to jillions of different versions of physics.

Multiverse also appears to be a cop-out: getting off the hook of not providing an explanation for the big bang. Personally I expect that an explanation of what led up to bang will eventually be worked out and will make testable predictions that one can check against ancient light. But in the meantime some people prefer to give up on that and say the universe just happened because of "quantum uncertainty". This sterile idea leads to no predictions of observable phenomena. But it does lead to the imaginative vision of a vast array of bubble universes--because if one can spring into existence why not jillions?--and that splendid imagery can boost booksales and ratings.

I agree with pretty much all you say here, Marcus. And it does need saying. When multiversian guff starts being promoted as science, and a search for M-Theory occupies shoals of very intelligent physicists for long years, fashions they are a-changing. The last and most important member of your trinity of physics virtues; "observing modeling predicting" may be in the process of being discarded.

On today's physics frontiers (strings, different flavours of quantum gravity, entropic gravity, entropic everything) it is often impossible or impractical to predict (rather than just explain what has been observed or measured). Instead, faut de mieux, it is becoming fashionable to place faith in plausible logical argument and mathematical ratiocination, i.e. in modelling to fit known observation.

Maybe this signals the transformation of physics into an art form, rather than a science?

 

[tom.stoer]

My problem with all this multiverse stuff is simply that it is claimed to be derived from theories that are incomplete and partially purely understood. Why should I believe in metaphysical concepts X, Y,... derived from an incomplete theory which is not able to explain physical entities a,b,c,...? Why should I do metaphysics instead of physics?

Introducing unobservable concepts is not forbiden in physics, but there should be the payoff of increased predictability.

 

[MTd2]

Multiverse is not even science at any level whatsoever. String Theory cold be at least tested, in principle, with a really huge and powerful particle accelerator and a very sensitive detector. Multiverse is just a fluke.

 

[Finbar]

The multiverse is a paradigm and while currently it leads to no predictions this does not mean that one day it will. Think of the paradigm of the atom which goes back to the ancient greeks. It was only thousands of years later that the atom was used to understand physics and predict new physics. The point is that a new paradigm allows one to formulate new models of the universe which could not exist within the old paradigm. The multiverse therefore offers a frame work in which to build new models of cosmology. These models can then offer predictions which can be tested.


I think many posts on here seem to offer a somewhat narrow view of what science is.

 

[MTd2]

Multiverse does not any new framework. It just shows that universes that we cannot observe exist. This is not like the many worlds interpretation of quantum mechanics in which every world has an interference on others.

 

[tom.stoer]

If one new testable prediction arises from the multiverse hypotheses I am willing to accept it a physical concept. Otherwise it's metaphysical speculation. Don't get me wrong - metaphysics is not irrelevant, uninteresting, ridiculous or something like that. But it is not physics.

 

[marcus]

If one new testable prediction arises from the multiverse hypotheses I am willing to accept it a physical concept...

There are several pictures that one can call Multiverse. As most of us probably realize, Smolin has proposed a picture which he claims makes a testable prediction---because it includes an observable reproductive mechanism (collapse to astrophysical black hole) accompanied by gradual mutation of parameters. If the cosmos actually did proliferate by such a mechanism one would predict that the parameters of physics would typically be such as to favor the reproductive mechanism---and not be improvable by any small change.

So far, says Smolin, no one has discovered any small change in the standard models of particle physics and cosmology that would have caused formation of more astrophysical black holes.

I don't want to promote that particular multiverse story here, and I don't think it is what today's popular Multiverse books are presenting. I just want to acknowledge that in very special cases some kind of testable prediction is possible.

 

[marcus]

Actually what concerns me about today's Multiversans is what I take to be a careless disregard for testability.

By itself multiversery is simply the notion that the cosmos might have different regions with different physical parameters. We have no reason to object, as long as they can point to a testable prediction from such a model.
Too often it seems as if a multiverse message is being used as a cover or excuse for theories not making any predictions at all.

 

[Fra]

I share a lot of the objections to multiverse thinking that has already been mentioned but to just add my additional opinons...

So maybe we should talk about Multiverse thinking. What is it grounded in? Is there a basic scientific motivation for it?

I can see two ways to arrive at "multiverse" reasoning.

1) By means of considering "mathematical possibilities" of structure of reality, and try to interpret them as different universes, but where only one of them seem to corresponds to the world we live in.

My opinion there is that misguided confidence in the "reality" of these mathematical possibilities then imply the confidence in these multiverses.

But it's utility or point is still UNclear. The attempts I'm aware of such as anthropic arguments as to why only some support life seems like irrational desperate arguements to seek a way out of the trap created by the misguided confidence in "mathematical possibilities" with no lack of physical evidence.

2) By confusing "many observers" with "many worlds". IMO, structural realism as a rejection of too much subjectivity risk leading to multiverse conclusions. If several possible conclusions seems possible and you fail to recover the consistency by simple observer-observer transformations like we are used to, then it seems like a short step to assume that these represent different universes and that these observers live in different universes and thus will never interact = problem solved.

But this is IMHO, cause also by insisting on structural realism in certain forms. I'm not saying that structural realism must lead to multiverses, but I personally see a relationship.

/Fredrik

 

[Dmitry67]

Actually what concerns me about today's Multiversans is what I take to be a careless disregard for testability.

By itself multiversery is simply the notion that the cosmos might have different regions with different physical parameters. We have no reason to object, as long as they can point to a testable prediction from such a model.
Too often it seems as if a multiverse message is being used as a cover or excuse for theories not making any predictions at all.

testability? falsiability?
who is talking about that stuff now? :)
seriously, what is a difference between talking about infinite Universe (hence making unfalsifiable claims about something beyond our Hubble volume and even beyond the cosmological horizon) and talking about multiverse in MWI sense or superstring/bulk sense?
The first type of multiverses is called type I by Max Tegmark, others are called type II and III. But they are all unfalsifiable.

 

[marcus]

I recall Tegmark's colorful SciAm article of some years back. As I recall there were 4 types of Multiverse, but maybe you are right and there were just 3 types. Intriguing exercises of imagination, for those who like such things.

I don't want to argue with you about Einstein's "cosmological principle". Basically it is an Occam simplicity and burden-of-proof issue.
As long as we see no phenomena indicating NON-uniformity, the default assumption is simply a bland boring "more of same".

And no elaboration needed as to what "more of same" means. It is simply same enough to have no effect on us. We don't need to make up fantasy details, like different laws of physics or two-headed people.

If you like to do that, you CAN make up fantasy details and you can calculate the probability that within a certain number of lightyears there would exists a planet just like Earth except the Confederacy won the Civil War. My feeling is that it is literature and that we don't need to do that from a science standpoint, but anyone who wants can do it for entertainment. Sort of recreational mathematics, or recreational cosmology.

Max Tegmark's illustrated Multiverse article in the SciAm had quite a bit of that, as I recall.

 

[Dmitry67]

I recall Tegmark's colorful SciAm article of some years back. As I recall there were 4 types of Multiverse

Yes, there were 4 types, I just did not want to mention type-IV.

I don't want to argue with you about Einstein's "cosmological principle". Basically it is an Occam simplicity and burden-of-proof issue.
As long as we see no phenomena indicating NON-uniformity, the default assumption is simply a bland boring "more of same".

Marcus, sorry, but this logic is absolutely inconsistent!

Your "more of same" principle applied to QM gives MWI: "more of same" branches of reality. Unless you break the symmetry, claiming the existence of some sort of "langoliers", eating other braches of MWI reality leaving only one branch intact.

If the burden of proof of existence of MWI worlds is mine, then the burden of proof of other Hubble volumes is yours. Until then, nothing exists beyond our visible Universe :)

If we apply consistently "more of same", we get Universe infinite in space and with infinite histories.

We can't turn Occam's razor to 180 degrees depending on the case just because some things are more plausible to our common sense reasoning (psycologically it is very easy to accept an infinite universe, but not an infinite number of histories)

Your choice?

 

[marcus]

When Einstein enunciated what is now called the Cosmological Principle he was not talking about Quantum Mechanics or "Many Worlds Interpretation" (which hadn't been invented.) . He was just talking about cosmological models. The Cosmo Principle basically says "keep it simple, don't make up stuff (like a boundary), unless some observation requires it just assume more of same".

It is related to the Copernican principle, or the with principle of Mediocrity. The Ordinariness of our situation.

You sound excited Dima. Don't get caught up in some flight of fancy and start mis-applying a simple and traditional default assumption from Cosmo to other stuff. Or I will just have to let you rave---can't argue with this kind of stuff.

In case anyone is curious a source often cited for the Cosmo Principle is Einstein's 1917 article "Kosmologische Betrachtungen zur allgemeinen Relativitätstheorie."

 

[quantumkiko]

He was just talking about cosmological models. The Cosmo Principle basically says "keep it simple, don't make up stuff (like a boundary), unless some observation requires it just assume more of same".

I agree with the above quote and most of what you've said in this forum regarding science. I remember watching a video about Dark Matter by Arkani-Hamed during the part when he was showing both the theoretical and observed rotational curves. He goes on to say that if the results don't agree or "unless some observation requires it", we start from something we already have and just tweak it a bit. He then goes on to"assume more of the same" by putting more mass that we haven't seen yet, thus the case for dark matter. This is very much in the spirit of science that Einstein was talking about. Ideas that go against the narrowness of science should only be considered as last resorts, not foremost ones. =)

Anyway, maybe the Multiversians didn't have Karl Poppers existing in their universes. =P

 

[marcus]

It looks like Smolin's conjecture has been refuted by neutron star observations.
https://www.physicsforums.com/showthread.php?t=442375

This week Amazon began taking advance orders for The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos, Brian Greene's new book. It is already up there on the physics bestseller list. Release scheduled for 25 January 2011. Looks like a hot one.

Here is the publisher's page on the book:
http://www.randomhouse.com/catalog/display.pperl?isbn=9780307265630

The blurb is slightly more toned-down and dignified than what you get at the Amazon webpage. I'll quote part of it:

==quote Random House webpage about the book==
From the bestselling author of The Elegant Universe and The Fabric of the Cosmos comes his most expansive and accessible book to date—a book that takes on the grandest question: Is ours the only universe?

There was a time when “universe” meant all there is. Everything. Yet, in recent years discoveries in various branches of physics and cosmology have led an increasing number of scientists to consider the possibility that our universe is one among many. Parallel worlds or parallel universes or multiple universes or alternate universes or the metaverse, megaverse, or multiverse—they’re all synonymous and they’re all among the words used to embrace not just our universe but a spectrum of others that may be out there.

With crystal-clear prose and inspired use of analogy, Greene shows how a range of different multiverse proposals emerge from theories developed to explain the most refined observations of both subatomic particles and the dark depths of space. And, with his unrivaled ability to make the most challenging of material accessible and entertaining, Greene tackles the core question: How can fundamental science progress if great swaths of reality lie beyond our reach?
...
==endquote==

How indeed? Truth out of the mouth of blurbs. The book has 400 pages and will be issued simultaneously in hardcover, e-book, audio CD, and audio download versions.

 

[S.Daedalus]

I agree viscerally with the spirit of many of the comments in this thread -- I find an infinity of universes simply aesthetically displeasing, and would have trouble intellectually accepting it even if I saw no other option for a consistent picture of reality. My main problem with many worlds is that among them seem to be some downright unreasonable ones, where the improbable is the norm -- say, every time anybody throws a coin, it always comes up heads, by pure chance. Imagine trying to do science in such a world!

However, I don't think it's quite that easy to exclude the possibility of a multiverse. The common argument, that the postulate of alternate worlds adds no explanatory power and hence should be discarded by the principles of good science is flawed, I think. Occam's razor demands the minimality of explanatory entities present within a theory, not the minimality of existent entities. So, strictly speaking, a theory with few explanatory entities that explains observations, yet yields to a proliferation of 'inaccessible' structures without observable consequences arguably is to be preferred over a theory that needs more explanatory entities to 'cast out' these unwanted structures without explaining the data any better. For a concrete example, the MWI essentially only contains the wave function and its evolution, while competing interpretations typically contain all that plus a mechanism for wave function collapse, or even some substratum of 'hidden variables'. In this sense, as Dmitry67 above argued, if we constrain ourselves to accepting only 'more of the same', rather than inventing something new without pressing need, we do indeed end up with many worlds.

It's also not quite necessarily true that multiverse proposals don't make any predictions; one example, Smolin's CNS was already mentioned, however, I'm aware of at least one other proposal that has testable consequences, proposed by Laura Mersini-Houghton, working from the proposed string landscape, which predicts a bound both from above and below for the SUSY breaking scale, and, more strikingly, predicted the existence of a cosmological void and a 'dark flow' before either were discovered. So this is a model which does in fact seem to have some observational support, though I am not familiar enough with the details of the model to comment well-informed enough.

Regardless, this pushes multiverse physics into the realm of observation, where of course all good science takes place: if, for instance, we found some sort of 'objective collapse' mechanism, or some substantiation for the existence of hidden variables (whatever that might look like), or generally any way in which observable reality differs from bare-bones quantum mechanics, we could conceivably exclude Everett-style multiverses; or if, on the other hand, the LHC failed to observe SUSY at the appropriate scale, or the dark flow turns out to be a measurement error, or there is no similar CMB cold spot opposite to the one already discovered, then we could exclude Mersini-Houghton's proposal.

 

[MathematicalPhysicist]

It looks like Smolin's conjecture has been refuted by neutron star observations.
https://www.physicsforums.com/showthread.php?t=442375

This week Amazon began taking advance orders for The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos, Brian Greene's new book. It is already up there on the physics bestseller list. Release scheduled for 25 January 2011. Looks like a hot one.

Here is the publisher's page on the book:
http://www.randomhouse.com/catalog/display.pperl?isbn=9780307265630

The blurb is slightly more toned-down and dignified than what you get at the Amazon webpage. I'll quote part of it:

==quote Random House webpage about the book==
From the bestselling author of The Elegant Universe and The Fabric of the Cosmos comes his most expansive and accessible book to date—a book that takes on the grandest question: Is ours the only universe?

There was a time when “universe” meant all there is. Everything. Yet, in recent years discoveries in various branches of physics and cosmology have led an increasing number of scientists to consider the possibility that our universe is one among many. Parallel worlds or parallel universes or multiple universes or alternate universes or the metaverse, megaverse, or multiverse—they’re all synonymous and they’re all among the words used to embrace not just our universe but a spectrum of others that may be out there.

With crystal-clear prose and inspired use of analogy, Greene shows how a range of different multiverse proposals emerge from theories developed to explain the most refined observations of both subatomic particles and the dark depths of space. And, with his unrivaled ability to make the most challenging of material accessible and entertaining, Greene tackles the core question: How can fundamental science progress if great swaths of reality lie beyond our reach?
...
==endquote==

How indeed? Truth out of the mouth of blurbs. The book has 400 pages and will be issued simultaneously in hardcover, e-book, audio CD, and audio download versions.

How many more pop-crap books do they plan to write?!

 

[Demystifier]

Anyway, MWI is no longer MWI is it? It's just no collapse of the wave function, which is common to MWI and Bohmians, unified under decoherence, isn't it?

There is no consensus, but I would quite agree with that.

 

[John232]

I sure anyone looking for the answers to the questions he raises will be disappointed. I have read some of those and none of them give a real answer to any of them.

I dought a particle could decay through time and hit a fly changing its course causeing it to land on me createing a whole other universe because I swatted at it unlike how I would have orginally if it hadn't decayed and hit that fly.