malpensante

i hereby want to gain more knowledge of arguments for and against a parallel universes worldview. so far i've read some very good ones for it in a book by david deutsch called "the fabric of reality". the parallel universes worldview says that there are many differing universes, in some of which there is life, in some of which there isn't, etc. and the set of all of them is the multiverse.

causality: this noution is troubled from the normal worldview of one universe. if every instant of the universe needs every other instant in the universe to be the way it is, then it cannot be said that one particular instant is caused by another instant. all of the instants are equally caused by all other instants, past and future. but causality is more compatible with a multiverse, because, let's take the following definition for causality:

X causes Y if: both X and Y occur, and most variations/deletions of X end up with Y not occurring.

now, if we have many universes, there are universes where there are events X which are linked to events Y, and in the parallel universes where everything else is the same, except that X is different or doesn't occur, y doesn't occur.
so, causality makes more sense in the multiverse.

probability: in the one universe worldview the probability needs some mechanism thru which to become actualized in the face of adjacent probabilities which aren't realized for some misterious reason. in the multiverse the definition of probability is:
if X is a probable event, then X occurs in at least some universe(s). so, things don't go from possible to actual. we are the ones who advance thru a set of universes in which X's happening is undetermined, in a branching of universes in which we only take one path at every instant, into universes where X's happening (or not happenning) eventually reaches 100% determinability.

these are some of the arguments for parallel universes, can some of you give me more arguments, and counterarguments?

EDITION ADDITION:

free will: if you have a ticket for last week's lottery, but have not yet found out whether you have won, the outcome is still open from your point of view, even though objectively it is fixed. but, subjectively or objectively you cannot change it. the common-sense theory of free will says that last week you still had the power to change the outcome, but this is incompatible with one universe, because in it, the future is already there (at least in god's eyes), and its opennes is an illusion. but according to the multiverse view, the many possible futures are already there, and in all of them it was you who decided what to do with the ticket.

Jobar

(mal, I got all your messages; if you are having trouble with PMs, I suggest you go to the Bugs, Problems & Complaints forum, and post a short description of what's happening. I'm not expert enough in vB to help out.)

Your topic is in the right place, mal, because the many-worlds theory of quantum mechanics is still in the realm of philosophy. We have no way to verify or falsify it, as of yet. Although Hawking and other physics heavies ascribe to it, there is nothing yet approaching proof. Most of the math seems to work, but there are serious problems with mass-energy conservation- or so I have read, I don't claim to follow that level of mathematics.

I will mention some fascinating, and mind-bending, consequences which might entail if the theory is true. It may be that not only are all physically possible universes (that is, the physics we observe) exist; it could be that all conceptually possible universes exist, somewhere in the infinite sheaf of universes which compose the multiverse.


Think about that. It may be that every dream or fiction ever created by humans is, somewhere out there, real! John Carter walks the sands of a Mars nothing like the one we see. Captain Kirk and Mr. Spock boldly go forth on the Enterprise. Merlin and Arthur, in many different incarnations, live out every legend ever written or spoken, and an infinite variety of others, too.

This is a fairly old idea in science fiction; I think the first story to use it was Larry Niven's All The Myriad Ways, written back in the sixties. My own personal favorite is Robert Heinlein's The Number of the Beast. I'm sure all the sf fans here will chime in with their own favorites.

A multiverse like this would be 'infinite in all directions'. One consequence would be that there would be an infinite variety of Gods- each infinitely powerful within his own universe. Think hard about that one- until your head starts to spin, then stop. Because our minds can't deal with not just infinite, but transfinite reality.

I use a mathematical analogy here, when I think about such things. You know that set of all whole numbers is infinite. Yet when you consider the set of rational numbers, it seems clear that it is greater than the (already infinite) set of whole numbers. And the set of all irrationals is greater yet.

(I have a friend on these boards, wade-w, who is a mathematician, and a mod in the ~Elsewhere~ forum; get him to talk about set theory. One day when you feel like you understand the world a bit; wade will rapidly disillusion you. )

Where I am going with this is that a God who has dominion over all these multiple worlds cannot be conceived. And a God such as you describe- who can 'step outside' of our perceivable universe, and thus allow omniscience and free will in our universe, is not truly God- because there are universes he cannot control, or even know about!

Positing a transfinite multiverse-God is no answer, either- because such a being would be aware of every possible universe, just as the God we more commonly think of is aware of every possible choice made in His creation. And thus, is incapable of creating true freedom.

Bill, Nial- if you want to, move this thread to EoG. Malpensante is an old friend of mine, and I think his topic here might fit better in EoG.

excreationist

From Wikipedia.org:
That article also talks about some other related things, like the Quantum suicide thought experiment.

A David Deutsch quotation from "New Scientists":
Here is recent story about the latest quantum computer developments.

Another advantage of the parallel universes idea is that it can be used as a way of explaining how very unlikely things, like the evolution of humans, became a reality... that's assuming that it is in fact, very unlikely. I thought of that idea... I don't know if anyone else has.

excreationist

I don't see where God comes into it.... perhaps it could go in the Science and Skepticism forum though.

Perhaps...

Well if quantum events happen in discrete time intervals then there wouldn't be so many possible histories up to this point in time compared to if time is continuous. Perhaps the universe dies in all of the possible histories and the infinity problem is solved. I guess just because there are a finite number of particles in our universe and a finite past history it doesn't necessarily mean that it isn't possible that there are an infinite number of alternate histories.

malpensante didn't mention God at all in his post. I think the idea of the conscious-type being that rules over the worlds hasn't got much support amongst respected scientists who support MWI (multiple worlds interpretation). (I think Hawking prefers "Multiple Histories")

Again, malpensante didn't mention God at all. Your mentioning God is what is turning this into an EoG thread.

malpensante

jobar:
i think you got confused, the topic on arguments for the multiverse worldview is philosophical, it's just a post i did in a thread which has already been moved which refers to god in the multiverse (the thread is called: An all-knowing God and Free Will: Can they both exist?). i gather that if the multiple universes split from single branches into their multiple paths, the splitting requires an extra energy, but what if it's not a splitting, but rather that the whole universes are there already, and the "splitting" is just the subjective experience of passing from being potentially in both universes (say the ones where a coin toss yields heads, and the one where it's tails), to being actually in one (say, the one where only tails becomes actual), but i read that this view is mathematically flawed, i don't know much either.

would you agree with me that the set of all conceptually possible universes is a subset of the set of all physically possible universes, and not viceversa? and yet some seemingly physically possible universes turn out to be inexistent in the multiverse, according to deutsch, demonstrably according to a method analogous to the cantor method of the diagonal to show that there are numbers that are not amongst the set of all numbers, and further, that the set of these absent numbers is infinite. thus, by diagonal argument, there are physically possible universes which are not in the multiverse, and they are infinite in number.
(jobar, i have answered your comments on multiverse god in the other thread).



excreationist:
indeed, both supporters and dissenters of the multiverse view use the occam's razor, but according to deutsch the supporters apply it where it is most crucial to do it: the explanation of reality. the explanation of the phenomenon of interference (along with the philosophical matters i already outlined, like causality and probability), is simpler. whereas the occam's razor is applied by dissenters to the number of worlds. according to deutsch this difference stems from an underlying assumption that differs between dissenters and supporters (which is discussed already by popper):

science doesn't work by induction from observation but by problem solving applied to the seeking of better explanations of reality.

deutsch also says that one of the reasons why there are dissenters is because most of physics doesn't need to be concerned by the process that actually goes on when a quantum experiment occurs, only its output, as a means for calculating other values of more interest. but almost the whole of the fraction of people who are already taking the multiverse worldview come from the two branches of science which do need to be concerned with the actual intermediate process, not just its output: quantum cosmology and quantum computation.

i've recently read in a book by clifford pickover called the paradox of god, that max tegmark, one of the proponents of the quantum suicide gedankenexperiment, has come up with a nice mathematical argument for the multiverse: the computational expression of a single random number within one and zero (with all its infinite decimals)is longer than the computational expression of the whole set of numbers that exist between 1 and 0, so, it may be more informationally economic for reality to consist of infinite parallel universes instead of just one. (pickover gives the computer code of such program, and it's only two lines long).

deutsch argues in his article ""Comment on “‘Many Minds’ Interpretations of Quantum Mechanics by Michael Lockwood”"" (which is available here: http://www.qubit.org/people/david/Ar...nLockwood.html )that the word "parallel universes" is better than "multiple minds", "multiple histories", and others, that are also given to this same theory. i think "multiverse" is better than "parallel universes".

the thinking on whether the multiverse view supports or refutes the antrhopic principle (the view that, humanity being so improbable, its existence couldn't have been by chance), is confused. the difference between the ones who think multiverse refutes or supports the antrhropic pple, lies in the set of the multiverse they look at: from one viewpoint it is clear that the improbability of humanity makes the universes where it occurs a vanishingly small set of the multiverse, giving humanity no physical relevance. from another viewpoint the set of human-friendly universes is itself infinitely big, giving humanity physical relevance. both viewpoints are right. transfinite math makes that possible.

the idea of the multiverse god comes from clifford pickover.

excreationist

malpensante:
About the quantum suicide thought experiment... what do you think would happen? Would people's "souls" (consciousness, memories, etc) instantly be transported to the afterlife at death? Or does the afterlife only begin on judgement day, far, far in the future when God physically resurrects people?

What is that computer code? I wonder how the increment between the numbers is represented... maybe as 1 divided by infinity or something... But anyway, the set of an infinite number of numbers is infinitely long... but one of the numbers is just one number... though it has an infinite number of decimals so it would need an infinite amount of storage space too...
BTW, opponents to the MWI probably wouldn't believe in random numbers with infinite resolution anyway... quantum things are quantized. So I don't think it is a very good argument.

Deutsch seems to refer to "the multiverse" quite a bit in that article.
e.g. "This is what motivates referring to each of these layers as a universe, and to layers of the multiverse collectively as parallel universes"
I can't find anywhere where he criticizes the use of the word "multiverse". He seems to use "multiverse" and "parallel universes" fairly interchangeably. With "multiverse" he is able to make more of a title out of it, i.e. "The multiverse" - it clearly is about the system in its entirety. "Parallel universes" emphasizes how there are "layers" that are similar.
I think a better term would emphasize how things branch off - like a tree... but I'll just use mainstream terms like MWI or the multiverse or whatever. The problem with "multiverse" and "multiple worlds" is that it doesn't point out that the worlds had common histories, then diverged at various points throughout time. "Multiple histories" emphasizes that very well. I think Hawking prefers the term "multiple histories" to "multiple worlds" (MWI)
e.g. from neo-Newton.com "Some have even combined branes with the MWI based on this principle, so that there is one universe with "multiple histories" projected by the brane (Hawking 80-93...)"
There was also another more specific statement that Hawking preferred to talk about "multiple histories" but I can't find that link.
BTW, I don't think Deutsch specifically criticized "multiple histories" in that article... he just mostly ignored the term and used the terms "multiverse" and "parallel universes".
update: I found some matches for Hawking and parallel histories. And more still just for searching for hawking "multiple histories". It looks like Richard Feynman invented or at least supported the idea of multiple histories.

It seems that his book uses the idea of the multiverse to defend the idea of God's omniscience and probably fairness, goodness, etc, while somehow keeping freewill. BTW, if a multiverse is required for a conscious being to have free-will, are there an infinite number of parallel multiverses which allow God to do different courses of action - e.g. be evil, etc? Otherwise I guess God wouldn't have free will. That is just a quick question since this is actually in the philosophy forum.

Another supporter of the parallel universes idea is Julian Barbour, a philosopher who wrote "The End of Time". He thinks that the parallel histories exist as an eternal, unchanging entity, which he calls Platonia. Within the entity are all the points in time of each branch of history. The different configurations of the universes at those times are represented by the positions of the structure at those points... (something like that)... it is basically a tree, beginning from the big-bang, which then branches out.

malpensante

jobar:
those sf books you talk about are commented in clifford pickover's book, "the paradox of god". he himself, a while after, wrote his own sf book on the multiverse, called "sushi never sleeps", and i'm planning to read it. your words "infinite in all directions" bring to my mind some weird thoughts: what if some universes within the multiverse are spatially infinite? would they in turn act like a multispace, if not a multiverse? would infinite repeating versions of each event occur within those universes?

excreationist:
i think the quantum suicide is equal to a normal suicide in that the same personal history gets the experimenter to point a gun within his mouth, but for whatever reason, quantum or not, in some universes he shoots, and in some he doesn't. what would the difference be in terms of subjective trans-parallel-universal experience?

david deutsch, in the same book, writes about the physical plausibility of "omega point" theory, which refers to the nature of the end of the universe, according to which, if humans or whatever intelligent creatures are alive at some critical instant near the end of the universe, and they manage to take advantage of the geometry of the universe to gain an infinite amount of energy which according to the theory, the last convulsions of the universe will yield in an infinite amount of contractions occurring in a finite amount of time, they will become some god-like creatures living in an eternity of intelligence evolution, and they would probably be able to resurrect all possible or actual people for whatever purpose. when i read that, it was the first time in a long time i considered resurrection mildly probable.

the computer code is (i don't know computer code, i will just transcribe it): say '1st 1/1 = 1'; do i = to 10; jend = i-1; do j = 1 to jend; k = k + 1; say '#' k':'j'/'i'='j/i; end; end. (or something like that, in the REXX programming language). it translates to: start at 0, step trhu 0.1, 0.2, 0.3, and so on, then 0.01, 0.011, 0.21, 0.31...

the important thing is that the whole sequence is specified by a process that can make any number of numbers while it lasts (and by the way, if omega point theory is right, then it could last forever), but the other procedure, that of making a whole number from scratch, might never end making that sole number, and the program specifying it would need to be at least as long as the number itself, so a multiverse requires less information, is simpler, less wasteful and more likely than a monouniverse.

by the way, pickover uses the argument to wonder if polytheism is more plausible than monotheism, he calls it "the physics of polytheism".

yes, i had already seen the page on platonia, after i had read about it in an interview barbour gave to www.edge.org and which is still there, online.

i think multiple histories and multiple universes is the same. only, multiple histories is also something that does happen within one single universe, so it is maybe a little more specific to talk about multiple universes.