As explained by Tegmark, the universes do not split. The wave function is the totality of reality, and it contains many diffrerent versions of the world.Quote:
Originally Posted by mal4mac
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As explained by Tegmark, the universes do not split. The wave function is the totality of reality, and it contains many diffrerent versions of the world.Quote:
Originally Posted by mal4mac
I'm just trying to understand. I don't really know what it means to be a fan of the model view of reality. Perhaps I was trying on an idea in the past. MWI still sounds too much like science fiction to me, but this is a literature forum.Quote:
Originally Posted by mal4mac
Well, the Copenhagen interpretation is also a mathematical view of reality. The main difference between it and MWI is that MWI keeps all the outcomes, even those that don't happen, while CI just hangs onto what actually happens in the real world. Regardless of the existence of multiple worlds in which we supposedly exist, there is only one world that need concern us.Quote:
Originally Posted by Cioran
I think the MWI approach is interesting because it forces people to define their positions better. There is nothing like contention to clarify issues. And who knows? It may be right, but I have no intention of being the cat in a quantum suicide experiment.
Here is a PBS interview from a few years ago about the Many Worlds that is very accessible to the lay reader (the Tegmark paper, not so much). It also talks about the shameful way Hugh Everett, who first mooted Many Worlds, was treated by some of the founders of original Copenhagen QM and their acolytes -- Einstein not among them, because he, alas, had died two years before Everett unveiled his theory which restored everything to 'QM that Einstein protested was lacking in it: determinism, realism, localism and no spooky action at a distance. Einstein opposed Copenhagen because, of course, Copenhagen is ridiculous. It's worse than magic or saying "God did it."' It is true that Copenhagen successfully "models" the world, in such a way that useful predictions can be made and we can build televisions (which depend on QM to work. So does your computer) This only goes to show that science is not (necessarily) about finding out the truth of the world, but only in making sucessful predictions that are instrumentally useful. Einstein, though, because he was a classical natural philosopher and not just a "shut up and calculate" modern scientist, wanted to find out how the world really was. He died two years before he would have gotten his answer from Everett.
ETA: of course, that is only in this branch he died before Everett unveiled MW. In others he lived and remarked upon it. But then again, Mitt Romney was elected last week somewhere on the wave function, and somewhere else Hitler won the war.
I had the impression you believe there is no reality, there are only models. So neither Copenhagen or MW interpretation reflects reality, they are just models.Quote:
Originally Posted by YesNo
Quantum mechanics consists primarily of mathematical equations describing the world of the very small. This is something that it does very well, with only one problem; these equations defy common sense. Hence the scramble to provide interpretations like "many worlds" theory or the Copenhagen Interpretation. From the point of view of instrumentalism such interpretations are unnecessary as all quantum theory needs to do is predict the behaviour of atoms and molecules.
So you can give an account of the results of the double slit experiment, and you can provide the equations that predict the results. But you can't provide an explanation that appeals to common sense. You say "I'm just trying to understand", but you never will, because nobody understands it, and you aren't the one person in seven billion who will make the conceptual leap to understanding (are you?)
"I think I can safely say that nobody understands quantum mechanics.", Richard Feynman, in The Character of Physical Law (1965) [... an exceptional book, by the way]
This is probably the most repeated quote in modern physics, often quoted wryly by aged physics professors to their over-avid students, followed by the second favourite quote "Shut up and calculate" - down to David Mermin.
So the main thing you need to understand, I suggest, if you and your seven year old are wanting to avoid being totally lost in frustrating perplexity, is that *you cannot understand it*. If he says "you mean *you* don't understand it dad," you can produce the key quote from the greatest physicist since Einstein...
P.S. If you tell your seven year old this, when he's a teenager, trying his hardest to prove dad & everyone wrong, he just might be that one in seven billion :)
The Quixotic nature of that particular quest was revealed by Kant in his first critique. If you want something racier & more modern than that I recommend taking a crack at "Integral Spirituality" by Ken Wilbur. This also has its Quixotic aspects, but it takes Kant & post-modernism seriously.Quote:
Originally Posted by Cioran
When I encounter science fiction containing ideas of parallel universes, I previously thought this was some nonsense these authors came up with. I didn't realize anyone actually believed other worlds were true. Also, when I heard the Schrodinger's Cat paradox, I didn't think that anyone believed this actually happens to a real cat. Apparently, the MWI supporters believe that a real cat in the experiment actually is still alive in some other world.Quote:
Originally Posted by Cioran
As far as "spooky" stuff goes, what MWI does is replace spooky action at a distance with spooky other worlds, which is actually spookier in my opinion.
mal4mac suggests I might be an "instrumentalist" which is what I suspect I am. Since all of these interpretations work, it is more like a religious choice which interpretation one prefers. Hmmm, Krishna or Jesus?
-------
Just thought of something! Perhaps Occam's Razor should be modified or why not create a new razor, call it the YesNo Razor :), that says the theory with the least spooky stuff is better all other things being equal.
Quixotic? and what a word? At first I thought the word exotic was there but then it said something different.Quote:
Originally Posted by mal4mac
How does one over idealise without going religious?
Invalid appeal to authority and also argumentum ad hominem, in fact. (Feynman is really smart, so it must be that no one can understand QM because this smart guy says so. This shows that not all ad hominem forms of argument rely on discrediting the speaker; some rely on praising him.)Quote:
Originally Posted by mal4mac
But, of course, we can understand QM -- and many other things besides! We are a very clever species.
The people who invented/discovered QM were shocked by it, because none of it made sense. It was inconsistent with classical reality -- our everyday world where things and people are only one way at a time, and behave in a common-sense fashion. After all, we never observe superpositions in real life -- but they exist at the microlevel. Ergo, something must make these superpositions "go away" at the macro level.
That "something" was put in by hand by the founders of QM -- they called it "wave function collapse." When a measurement of the micro world is made, the wave function is magically collapsed to instantiate a single version of reality, the reality that we all see. No explanation is offered of wave function collapse, no mechanism, no idea is mooted of how the wave function collapses instantaneously across the entire universe, and so on. It is all magic! This is as unscientific as one can be. This is why we get monstrosities like "shut up and calculate" from many modern scientists -- a notion anathema to the greats like Einstein, Newton, Galileo, and others. When it comes to finding out how the world really is, as opposed to mere models of it, modern scientists of the Copenhagen school punt. In fact they forbid you to talk about it -- like priests in a church forbidding you to question sacred Scripture.
Hugh Everett's key insight was to notice that there is no such thing as classical reality, and hence there is no wave function collapse. Reality is entirely quantum mechanical, from top to bottom. In effect, what the pioneers of QM were doing was splitting reality into two domains: the classical and quantum. Then, in setups like the two-slit experiment, they were treating the electrons going through the slits as a quantum world, which then interacted with the classical world of the observers.
Everett says no, everything is quantum, including the observers conducting the two-slit experiment. And of course this must be the case. We are made up entirely of quantum particles!
Everett is saying that when we do a quantum experiment, we are inside the quantum system, not outside it. There is no classical world.
This is why Schrodinger's attempted reductio of QM as a complete theory misfires. In his thought experiment, he was showing a way to "amplify" quantum mechanical effects at the micro-level all the way up to the "classical" level of a cat. And when you do that, (he says) you get a cat that is both alive and dead! This is ridiculous (he thought) and of course we never observe "classical" superpositions and so QM must be an incomplete theory. There must, Einstein insisted, be hidden variables to explain away the mystery of QM.
But there are no hidden variables. This was demonstrated experimentally beginning in the early 1980s. Contra Einstein, QM is a complete theory. Where he and the others went wrong, and where Everett corrected their error, was their assumption that the world is divided into classical and quantum domains. They had the right theory but the wrong interpretation of it.
In the case of the cat, there is no "amplification" of the quantum mechanical state to the classical state, because there is no classical state. The cat was, is, and always will be, in superposition. But now suppose Fred is conducting the cat experiment. What Fred has not taken note of (because he is indoctrinated with Copenhagen) is that he, Fred, is also in superposition; always has been, and always will be. Like the cat, Fred lives in many worlds.
Why, then, when Fred opens the box, does he see only a live cat or a dead cat but never both? But he does! Fred sees a live cat, and his superposed doppelgänger on the wave function sees a dead cat. It's true that neither Fred nor his doppelgänger see a live/dead cat at the same time, but that's because there are two Freds as well as two cats, and each reports a different outcome. What we call the classical world is a perspectival limitation, in which we take a small cross section of all of reality and assume this little slice is all that there is. Exactly the same thing happens, by the way, with relativity theory. Relativity theory shows that the past, present and future all exist. There is no such thing as "passing time," and no single "Now." What we call the "now" is a little cross section of a much larger existent reality in which the people of the past and the people of the future exist just as do you and I.
Well let put this idea to the test.
If one asks the time the probable answer is something like ''an hour and O'clock'' ie
Three O'clock
or
Ten O'clock.
These are precise answers that indicates that someone is talking time.
If then someone asks how long does it take and the answer is 45 minutes/3hours/2minutes. That becomes a number which could be quantified as quantum physic notions because take the 45 minutes/3hours/2minutes out of context and it is not specific to time or O'clock and could mean all sorts of meanings.
These answers although clock related they are not telling the time.
There are many superpositions in real life. You can find them every time you are presented with a choice. Prior to making the choice, whether a candidate on a ballot or when to step in a particular line at a store or whether to buy this brand or that brand, you are in a superposition of possible outcomes. You choose one of them. The others you do not choose. It happens all the time. There is nothing unusual about it.Quote:
Originally Posted by Cioran
It is easy to rewrite this from the perspective of someone who might support the Copenhagen interpretation as follows:Quote:
Originally Posted by Cioran
That "something" was put in by hand by the founders of QM -- they called it "world split." When a measurement of the micro world is made, the wave function is magically split to instantiate a new version of reality, the reality that we can't see. No explanation is offered of world splitting, no mechanism, no idea is mooted of how the world splits instantaneously across the entire universe, and so on. It is all magic! This is as unscientific as one can be. This is why we get monstrosities like "shut up and calculate" from many modern scientists -- a notion anathema to the greats like Einstein, Newton, Galileo, and others. When it comes to finding out how the world really is, as opposed to mere models of it, modern scientists of the Many Worlds school punt. In fact they forbid you to talk about it -- like priests in a church forbidding you to question sacred Scripture.
This is true, but the objects that make up each of us become something more than the sum of their parts. These combinations get names, like YesNo, Cioran, cacian or mal4mac, and can act and make free choices.Quote:
Originally Posted by Cioran
I'm mentioning "free choice" here to try to see whether you think we have any free choice or not. Because MWI is deterministic and carries the wave function into classical reality, I wonder if there is any freedom for the experimenter under MWI. I think I heard that MWI might be implying something called "superdeterminism".
These are not quantum superpositions. To experience a quantum superposition, you would have to vote both for and against a candidate at the same time, or buy and not buy a brand at the same time -- you would, in short, have to violate Aristotle's Non-Contradiction.Quote:
Originally Posted by YesNo
Easy to do, hard to be accurate. The above is a strawman caricature of what the Many Worlds says. Notwithstanding the fact that even Everett talked in a loose manner of "splitting" universes, nothing splits, as Tegmark explains in the paper that I linked. So your above re-write is simply a false description of what Many Worlds says. You might also read the layman-geared interview that I linked last night.Quote:
It is easy to rewrite this from the perspective of someone who might support the Copenhagen interpretation as follows:
That "something" was put in by hand by the founders of QM -- they called it "world split." When a measurement of the micro world is made, the wave function is magically split to instantiate a new version of reality, the reality that we can't see. No explanation is offered of world splitting, no mechanism, no idea is mooted of how the world splits instantaneously across the entire universe, and so on. It is all magic! This is as unscientific as one can be. This is why we get monstrosities like "shut up and calculate" from many modern scientists -- a notion anathema to the greats like Einstein, Newton, Galileo, and others. When it comes to finding out how the world really is, as opposed to mere models of it, modern scientists of the Many Worlds school punt. In fact they forbid you to talk about it -- like priests in a church forbidding you to question sacred Scripture.
Well, I agree that you can't vote both for and against a candidate in the real world, but I thought Many Worlds would have solved that problem. In one world I would vote for Candidate X. In the other I would vote for Candidate Y. At the point where I press the complete ballot button on the screen, there is no turning back. My one reality in the real world voted for Candidate X. My other reality in the cloned world voted for Candidate Y.Quote:
Originally Posted by Cioran
If that doesn't work as a quantum superposition according to MWI, then I'm confused. How does Schrodinger's cat pull that off? In one world the cat is alive. In the other world the cat is dead.
I am talking about experiencing a quantum superposition, which is what I thought you were talking about. We clearly don't experience them. But, yes, in one world you vote for x and in the other for y. You don't just don't experience voting for x and y at the same time.Quote:
Originally Posted by YesNo
That is exactly the bit that is missing.Quote:
Originally Posted by Cioran
We have not yet created a one combination for two combinations meaning if you place x and y together you should by law of quantum get a third combination that means it is an x and y together. That is the height of quantum.
Another question about quantum is this:
whilst we are able to determine our weight at a static phase, what is the actual weight for a non static object say thrown in the air?
Whilst the object is moving it has a determined weight are we able to tell it?
Quantum physic or meta-physics or quantum in the move?
Of course smart guys can be wrong, but in this case Feynman is right.Quote:
Originally Posted by Cioran
We can't understand it in terms of common sense, if you want to equate "having an equation" and "experimental results" to "understanding" then fair enough...Quote:
But, of course, we can understand QM -- and many other things besides! We are a very clever species.
How on Earth can they forbid you talk about it?! Why would they? There is no Copenhagen Inquisition marching round the countryside looking to burn Many Worlders... it's just that Many Worlders are not convincing... Galileo proved the moon wasn't an ideal object by producing a telescope, where is the MW telescope?Quote:
When it comes to finding out how the world really is, as opposed to mere models of it, modern scientists of the Copenhagen school punt. In fact they forbid you to talk about it -- like priests in a church forbidding you to question sacred Scripture.
Hugh Everett's theories have no general acceptance. In any case, this sort of arcane discussion should surely take place on physics forums, if anywhere, not here. It's bad enough having to suffer Big Endian discussion in ones own discipline without having one in someone else's discipline. Lay people should be protected from these kind of discussions...
For those wanting to dip their toe in "the other culture", a bare instrumentalist account is all that is needed, and the literate layman can happily avoid the "interpretation wars" that happen on the fringes of physics - most sensible physicists do, so they certainly should!
If we are in free fall we wouldn't have any weight. We wouldn't think we are moving either. Supposedly the laws of physics should be the same in these frame of references, but I wonder whether that is true for quantum physics laws.Quote:
Originally Posted by cacian
*Shrug* So you say. By the way, Feynman's elaboration of QM is essentially the Many Worlds.Quote:
Originally Posted by mal4mac
There are tons of things we can't understand in terms of common sense. The universe can, however, be described mathematically, and understood to a good degree in that way.Quote:
We can't understand it in terms of common sense, if you want to equate "having an equation" and "experimental results" to "understanding" then fair enough...
Did you read the essay I linked on Hugh Everett? Nobody said there was an inquisition marching around to burn Many Worlders; this is a silly strawman of what I said. But, yes, you're not supposed to talk about what this means; just crunch the numbers was a big thing in QM for a long time. Read about how Everett was treated after he unveiled MW. He was essentially driven out of doing physics! Which shows that scientists can be petty, defend their domains with sometimes religious fervor, and in general behave like anyone else; i.e., badly.Quote:
How on Earth can they forbid you talk about it?! Why would they? There is no Copenhagen Inquisition marching round the countryside looking to burn Many Worlders...
Not convincing to whom? MW is mainstream now, even boring. That's because Copenhagen with its magical wavefunction collapse is entirely unconvincing. Of course it's probably true that most scientists "shut up and calculate" and ignore what QM means. This puts them outside of the great tradition of the natural philosophers, like Galileo, Einstein and Newton, who wanted to understand how the world really was, and not just crunch numbers like mindless caclulators.Quote:
it's just that Many Worlders are not convincing...
Where is the Copenhagen telescope? But, since you ask, here are the Many Worlds telescopes: Quantum computation, in its infancy but working and Buckyballs observed to be in superposition. Both demonstrate the Many Worlds. David Deutsch, in his book the Fabric of Reality from some fourteen years ago, makes a convincing case that quantum computation proves the existence of the many worlds, at least as far as anything can said to be "proved" in science.Quote:
Galileo proved the moon wasn't an ideal object by producing a telescope, where is the MW telescope?
Sure, they do. Did you read the two papers that I linked? In his most recent book, Stephen Hawking talks not only about the Many Worlds, but about how in one of them the moon is made of Roquefort cheese! Literally! In any event, truth is not a matter of popular opinion, so the acceptance or non-aceeptance of a theory is irrelevant. Newton's theories were accepted for hundreds of years and are still taught in school, because they're useful. They're also wrong.Quote:
Hugh Everett's theories have no general acceptance.
Laugh out loud, protected? If you want to be "protected" from some of the most interesting philosophy and science that you will ever encounter, don't read this thread! But don't presume to tell others what they can read or talk about. This particular forum is about philosophical literature. Thus thus this topic is perfectly appropriate, indeed one might say paradigmatically appropriate, for this particular forum.Quote:
In any case, this sort of arcane discussion should surely take place on physics forums, if anywhere, not here. It's bad enough having to suffer Big Endian discussion in ones own discipline without having one in someone else's discipline. Lay people should be protected from these kind of discussions...
Right, exactly my point earlier, that the Copenhagen school of instrumentalism actually seeks to forbid these sorts of discussions -- which you yourself evidently are trying to do! Thanks for demonstrating my point.Quote:
For those wanting to dip their toe in "the other culture", a bare instrumentalist account is all that is needed, and the literate layman can happily avoid the "interpretation wars" that happen on the fringes of physics - most sensible physicists do, so they certainly should!
Yes - Sum over Histories, another insult to common sense. No wonder he said you can't [really] understand it!Quote:
Originally Posted by Cioran
Einstein was also "driven out" of physics, into the patent office, but it didn't stop him doing physics that was quickly *accepted by all physicists*.Quote:
Read about how Everett was treated after he unveiled MW. He was essentially driven out of doing physics! Which shows that scientists can be petty, defend their domains with sometimes religious fervor, and in general behave like anyone else; i.e., badly.
"World really was"?! I can here Kant and the Buddha laughing in heaven at that one... Galileo, Einstein and Newton just gave us models, QT is a mathematical model.Quote:
This puts them outside of the great tradition of the natural philosophers, like Galileo, Einstein and Newton, who wanted to understand how the world really was, and not just crunch numbers like mindless caclulators.
They don't forbid these discussions, how could they? They just try to discourage them, in the way that rational philosophers tried to discourage discussion of how many angels can dance on the head of a pin - there are better things to discuss.Quote:
Right, exactly my point earlier, that the Copenhagen school of instrumentalism actually seeks to forbid these sorts of discussions -- which you yourself evidently are trying to do! Thanks for demonstrating my point.
I don't know what you mean by experiencing a quantum superposition. I understand that MWI wants to extend the quantum wave to classical reality. I understand that MWI believes that Schrodinger's cat is alive in one world and dead in another. Perhaps I am wrong with those assumptions.Quote:
Originally Posted by Cioran
If I am not mistaken, I maintain that prior to voting the voter is in a superposition of (a) vote for X and (b) vote for Y. The voter has not yet chosen which it will be. In a similar way the photon is in a superposition prior to being measured of (a) spin up and (b) spin down. The photon has not yet chosen which it will be. When the voter makes a choice in voting, the machine registers that choice and a measurement is recorded. The voter should be in two different worlds now based on MWI. When the photon is measured, it also makes a choice between up and down and a measurement is recorded. The photon should be in two different worlds now based on MWI.
Perhaps MWI is false and there is only one world and looking at indeterminacy at the classical level rather than the quantum level is a way to expose the problems with MWI.
I have also been putting this in terms of "making a choice" and earlier with "free will". At the moment I am looking at Conway and Kochen's The Strong Free Will Theorem hoping to clarify some of the issues that MWI bring up for me: http://www.ams.org/notices/200902/rtx090200226p.pdf
I'm pointing out that some people felt (and many still feel) that there is a classical world in distinction to the quantum world because we never notice superpositions in ordinary life. They seemed to feel that unless the superposition of the quantum world "gave way" to what we called the classical world at some point, then we ought to experience superpositions in ordinary life -- actually experience being in many different states. But the MWI answer to this is simply that each of our "versions" experiences only one particular branch. In the case of the voter, the voter is always in superposition -- before, during, and after the vote. This is why, technically, there is no "splitting" -- everything is already "split" to begin with. But our minds are "split" among the different branches as well, so each mind experiences only a single branch and thinks (wrongly, under MWI) that that particular branch is the totality of reality.Quote:
Originally Posted by YesNo
What is this with your devotion to common sense? Does common sense tell you that the world is quantum or relativstic (it's both)? Did common sense tell everyone that the reason that the apple falls to the ground is the same reason that the moon circles the earth, or did it take civilization 5,000 some years until someone came around and figured that out? Common sense is a notoriously poor guide to the world. Do you recall what Einstein said about common sense?Quote:
Originally Posted by mal4mac
Excuse me? Einstein was "driven out of physics" into the patent office? Maybe you should check your history. As to being "accepted by all physicists," acceptance has nothing to do with whether something is true or not. Copernicanism was certainly not accepted for a long time, and Galileo's attempt to teach it as "true" as opposed merely to a model that gave identical predictions with Ptolemy gave him a fair spot of trouble with the Church, as I recall.Quote:
Einstein was also "driven out" of physics, into the patent office, but it didn't stop him doing physics that was quickly *accepted by all physicists*.
Of course it's a mathematical model. Are you saying that there can only be models, and the world has no actual true nature? If the world has no actual true nature, is it all in the mind, or a matter of opinion? Are you advocating philosophical idealism? Also, see above, on the debate of Ptolemy vs. Copernicus. Both provided models of the solar system. Both models made identical predictions. The Church told Galielo that it was fine to teach Copernicanism as a model to make predictions, but that it was not fine to teach it as showing how the solar system really is. And yet, it turned out that solar system really is heliocentric, and so Potelmy's model, while useful, was wrong. Here is a clear example of what you seem to be denying can happen: an example of a model not just being useful, but actually true. Would you deny that heliocentrism is actually true?Quote:
"World really was"?! I can here Kant and the Buddha laughing in heaven at that one... Galileo, Einstein and Newton just gave us models, QT is a mathematical model.
Read the piece on Everett.Quote:
They don't forbid these discussions, how could they?
This comparison is invalid. QM is a fact; angels are a fiction. When we discuss interpretations of QM, we are discussing a factual reality that, if it were not a fact, would instantly render your TV and your computer useless, among many other devices. So disucssing interpretations of a factual state of affairs has nothing in common with angels dancing on pins.Quote:
They just try to discourage them, in the way that rational philosophers tried to discourage discussion of how many angels can dance on the head of a pin - there are better things to discuss.
Again, if you don't approve of the discussion, feel free to recuse yourself from it.
I was reading Max Born's 1954 Nobel Prize address, "The statistical interpretation of quantum mechanics": http://www.nobelprize.org/nobel_priz...rn-lecture.pdf
In this address he wrote something about determinism that I think resolves the issue against the MWI. He describes how determinism started and remained as a belief that the laws of mechanics can accept an initial state from which all other states are derived.
Newtonian mechanics is deterministic in the following sense:
If the initial state (positions and velocities of all particles) of a system is accurately given, then the state at any other time (earlier or later) can be calculated from the laws of mechanics. All the other branches of classical physics have been built up according to this model. Mechanical determinism gradually became a kind of article of faith: the world as a machine, an automaton. As far as I can see, this idea has no forerunners in ancient and medieval philosophy. The idea is a product of the immense success of Newtonian mechanics, particularly in astronomy. In the 19th century it became a basic philosophical principle for the whole of exact science.
He then argues that one cannot get precise enough initial states to make predictions that remain accurate over time. His conclusion is the following:
I should like only to say this: the determinism of classical physics turns out to be an illusion, created by overrating mathematico-logical concepts. It is an idol, not an ideal in scientific research and cannot, therefore, be used as an objection to the essentially indeterministic statistical interpretation of quantum mechanics.
Born removes determinism from both classical and quantum physics. An initial state cannot be obtained that would allow any law to derive with adequate accuracy any future state after a certain point of time.
The MWI attempts to restore determinacy to physics by using a separate world for each branch in an indeterminate situation. This creates separate worlds in which QM should be true or MWI is not an interpretation for QM. However, if such an initial state and wave function existed for any particular world in the universe, that would contradict the indeterminacy of QM. Therefore, no initial state and wave function exists that will deterministically predict events for any particular world in the universe. Should such an initial state and wave function exist for the entire universe then in particular it would be a deterministic solution for some particular world and again QM would be contradicted. Therefore, no initial state and wave function exists that will predict all events for the entire universe.
And now for the conclusion:
Since MWI requires an initial state and wave function to exist for a deterministic physics either in each particular world or the universe as a whole, MWI is not a valid interpretation of QM.
Well, in honesty, I don't really follow your argument, YesNo. I'm not sure what the conclusion is supposed to mean, or how it derives from the premises. I don't really even understand the premises you are arguing.
I'd have to read Born's address, but I suspect what he is getting at is that determinism in a classical universe, even if true, is useful only in idealized states (as in the lab) because in tracing antecedent conditions, things get so complicated so fast that we can't trace the determinism.
This is true for all law-like statements about nature. We had to go to the moon and drop two objects of different size to determine them hitting the ground at the same time, because we needed a frictionless environment (no atmosphere, idealized) to show empirically that this is how nature behaves.
Many Worlds removes statistical indeterminacy from QM because the indeterminacy is a function of supposing there is wave function collapse. Without wave function collapse, a statement like, "there is a seventy percent chance that x will be found located at y, and a thirty percent chance that it will be found at z" resolves to seventy worlds with x at y and thirty worlds with x at z.
The goal of MW was not to restore determinism to physics. Rather, that was a consequence of the interpretation. The goal was to treat the whole universe as a quantum mechanical system, rather than arbitrarily split between a quantum world and a classical world; to show that this could be described mathematically (it can) and then to work out the ontological consequences.
While I'm far too ignorant about QM to discuss this on the level Cioran is, one piece of "common sense" philosophy I might introduce that could aid in his points is this: Consider that we evolved to be able to cope with and interpret reality in a manner that aided our survival. Most of our instincts and "common sense" comes from having to survive and reproduce, with surviving involving things like escaping from predators and being able to hunt and eat prey. This level of reality appears so differently to what happens on a quantum level that we have difficult grasping it. This is a limitation of our perspective, specifically, of how evolution has programmed us to think with regards to survival and reproduction. As I've said before, crocodiles don't need to understand QM in order to be able to eat and reproduce. It's entirely possible that reality is completely and utterly different to how we are programmed to experience, and, in fact, the history of scientific endeavor is an tome-like account of our common sense perceptions being subverted upon learning how things ACTUALLY work. Trying to understand MW on the level of our common sense, everyday experience would be like expecting a frilled shark to understand that the sun revolves around the earth. It's simply not a part of how they experience reality. The point of this is that what is true about the universe may very well never make sense to us on an intuitive, common-sense, instinctual level, for no other reason than that our evolution was not concerned with dealing with how reality actually works to begin with. We have to realize that our limitations of perspective may be the greatest thing preventing us from understanding how reality works.
That's a spectacular point MS.
It's neither.Quote:
Originally Posted by Cioran
You can't say what the world *is*. Even within the confines of physics, you can only produce models that predict things in different domains. For instance GR only works in the large, QM in the small. At the Big Bang we have both situations, and our little physics models break down. The human being evolved from slime into being a clever, if barely sane, ape. How can we expect such a being to understand "the world"?
I prefer to accept my limits as an ape and play in the sandbox of common sense. If you like to play with wacky MW models then fine, each to his own. But you shouldn't mislead people into thinking that MW is the answer to life, the universe and everything.
Common sense evolves, the Newtonian model that fits nicely into our limited ape mind, and so common sense adapts to take it in very happily. But the Quantum Interpretations do not, they make no appeal to common sense, that's why there are so many of them and why physicists who Quixotically refuse to "shut up and calculate" can't agree on a good interpretation.Quote:
Did common sense tell everyone that the reason that the apple falls to the ground is the same reason that the moon circles the earth...
By "driven out" of physics I was assuming you meant "was forced to take a paid job outside physics". But really "driven out" can only be used in an ironic fashion here, Everett wasn't, really, in any sense "driven out". Theoretical physics is something you can do anywhere, so how can you be driven out of it?Quote:
Excuse me? Einstein was "driven out of physics" into the patent office? Maybe you should check your history.
I agree, but it doesn't follow that any wacky interpretation is true. And discussing the wacky interpretations of Quantum Mechanics are not something that should be part of anyones general culture - it's a Big Endian activityQuote:
As to being "accepted by all physicists," acceptance has nothing to do with whether something is true or not. Copernicanism was certainly not accepted for a long time, and Galileo's attempt to teach it as "true" as opposed merely to a model that gave identical predictions with Ptolemy gave him a fair spot of trouble with the Church, as I recall.
Of course there can only be models. What do you mean by "true nature"? How can we know such a thing. We are only apes limited by our little ape brains. I'm advocating Kant's transcendental idealism, which aknowledges the limitations of our little ape brain. Read his first critique to "get" this...Quote:
Of course it's a mathematical model. Are you saying that there can only be models, and the world has no actual true nature? If the world has no actual true nature, is it all in the mind, or a matter of opinion? Are you advocating philosophical idealism?
Yes, it's just a better model.Quote:
Also, see above, on the debate of Ptolemy vs. Copernicus. Both provided models of the solar system. Both models made identical predictions. The Church told Galielo that it was fine to teach Copernicanism as a model to make predictions, but that it was not fine to teach it as showing how the solar system really is. And yet, it turned out that solar system really is heliocentric, and so Potelmy's model, while useful, was wrong. Here is a clear example of what you seem to be denying can happen: an example of a model not just being useful, but actually true. Would you deny that heliocentrism is actually true?
Actually Copernicus' model wasn't as good Kepler's, which showed that the Sun isn't actually at the center of the solar system, it's at the focus of an ellipse.
There is no way you can get to "actually true".
Nah. I've read too many pieces on Everett... I'm off to play internet chess...Quote:
Read the piece on Everett.
The results of QM experiments are facts, MW is a fiction. Actually people see angels in altered states of consciousness so they are less fictional than MW (or have you seen Universes splitting in your dreams...)Quote:
...QM is a fact; angels are a fiction.
You complained about people driving Everett out of physics, and now you're trying to drive me out of the thread!Quote:
Again, if you don't approve of the discussion, feel free to recuse yourself from it.
I'm sorry YesNo, I have to agree with Cioran here. I'm not sure what your conclusion is supposed to mean, or how it derives from the premises. I don't really even understand the premises you are arguing.Quote:
Originally Posted by YesNo
MW, Copenhagen, Transactional... are all valid interpetations, all valid models. Just like Copernicus and Ptolemy (with) Epicycles are valid models... Tycho Brahe had another intruiging model... an interesting "sun and earth centred model".
Maybe the main problem with quantum interpretations is that, speaking metaphorically, THEY ALL HAVE EPICYCLES. And who can be bothered with epicycles... far too messy... hence the nicety of instrumental approach... you don't have to think about epicycles, just apply the equations and look at the planets in the sky, and ignore the daft arguments between Brahe, Copernicus, Ptolemy, et. al....
By the way, Kepler was also wrong of course, the planets don't move in smooth ellipses, there is, for instance, a precession in the perihelion of mercury. This is predicted by Newtonian theory... but even that model is wrong! The precession of the perihelion of mercury is predicted accurately only by GR. And GR, as Quantum cosmologists point out, is a limited theory. So we don't have any grasp on the reality of the solar system, just a cascade of models that get more accurate, but become increasingly difficult to play with.
Great point MS! A point I made in my last post before reading yours... but you put it far better...Quote:
Originally Posted by MorpheusSandman
Cioran seems to think he is getting a grasp on reality through studying MW, but MS is far more compelling in his reasons why this is probably a futile endeavour. If, like me, you agree with MS, then why should anyone read Everett? I have read some Everett and it's not much fun; far better to read Dickens, or if you must explore "the big questions", a proper philosopher like Plato or Kant. Why get lost in backwaters like Everett?
And yet these same apes came up with GR and QM in the first place -- totally outside common sense, yet both work and are true.Quote:
Originally Posted by mal4mac
Each to his own.Quote:
I prefer to accept my limits as an ape and play in the sandbox of common sense.
I've never said any such thing. You should stop misleading others that others are misleading them.Quote:
If you like to play with wacky MW models then fine, each to his own. But you shouldn't mislead people into thinking that MW is the answer to life, the universe and everything.
You do know that Newtonian mechanics is false, right?Quote:
Common sense evolves, the Newtonian model that fits nicely into our limited ape mind, and so common sense adapts to take it in very happily. But the Quantum Interpretations do not, they make no appeal to common sense, that's why there are so many of them and why physicists who Quixotically refuse to "shut up and calculate" can't agree on a good interpretation.
He was driven out by negative ad homimen attacks that soured him on academia in general.Quote:
By "driven out" of physics I was assuming you meant "was forced to take a paid job outside physics". But really "driven out" can only be used in an ironic fashion here, Everett wasn't, really, in any sense "driven out". Theoretical physics is something you can do anywhere, so how can you be driven out of it?
So something that has captivated the greatest minds in science for a century is not something that should be part of anyone's general culture? I suggest you speak for yourself.Quote:
I agree, but it doesn't follow that any wacky interpretation is true. And discussing the wacky interpretations of Quantum Mechanics are not something that should be part of anyones general culture - it's a Big Endian activity
Thanks, I've read Kant.Quote:
Of course there can only be models. What do you mean by "true nature"? How can we know such a thing. We are only apes limited by our little ape brains. I'm advocating Kant's transcendental idealism, which aknowledges the limitations of our little ape brain. Read his first critique to "get" this...
Is true that the sun goes around the earth, or is it false? Once you admit it is false, then your whole argument that all we can have are models, and that there is no "true way" the world "is," fall to pieces, doesn't it?Quote:
Yes, it's just a better model.
Actually Copernicus' model wasn't as good Kepler's, which showed that the Sun isn't actually at the center of the solar system, it's at the focus of an ellipse.
There is no way you can get to "actually true".
This objection is remarkably vacuous. It's like someone in Galileo's time saying, "We don't feel the earth moving, or have you felt it move in your dreams?"Quote:
Nah. I've read too many pieces on Everett... I'm off to play internet chess...
The results of QM experiments are facts, MW is a fiction. Actually people see angels in altered states of consciousness so they are less fictional than MW (or have you seen Universes splitting in your dreams...)
Not at all. You keep complaining that people should not be talking about this stuff. So why are you still talking about it?Quote:
You complained about people driving Everett out of physics, and now you're trying to drive me out of the thread!
Ironically enough, I think you completly missed the point of MS's post. He's saying that we should not expect the world to conform to our common sense. I think that is correct, and it supports my interpretive arguments and goes against your own.Quote:
Originally Posted by mal4mac
I might point out that the theoretical physicist David Deutsch thinks we already have the empirical demonstration of the truth of the Many Worlds, and he wrote about this as far back as 1998 in his book The Fabric of Reality. The proof is quantum computers, which already exist in a rudimentary form.
Here in an interview with Deuttsch. A nicely relevant quote is produced below. (mal4mac, you may skip all this for Internet chess, of course!)
Quantum computers work by computing in superposition. That means real resources are really used; it’s real matter and energy. That means the other computers in the other words are real. That’s Deutsch’s position. It’s a pretty compelling point.Quote:
WN: How do you think using quantum computers will change how people think about computing, and consequently the universe and nature?
Deutsch: "How they will think about it" is the relevant phrase here. This is a philosophical and psychological question you're asking. You're not asking a question about the physics or the logic of the situation.
I think that when universal quantum computers are finally achieved technologically, and when they are routinely performing computations where there is simply more going on there than a classical computer or even the whole universe acting as a computer could possibly achieve, then people will get very impatient and bored, I think, with attempts to say that those computations don't really happen, and that the equations of quantum mechanics are merely ways of expressing what the answer would be but not how it was obtained.
The programmers will know perfectly well how it was obtained, and they will have programmed the steps that will have obtained it. The fact that answers are obtained from a quantum computer that couldn't be obtained any other way will make people take seriously that the process that obtained them was objectively real.
Nothing more than that is needed to lead to the conclusion that there are parallel universes, because that is specifically how quantum computers work.
I'm just beginning to understand this. I see that both you and mal4mac found it confusing, so maybe rephrasing it like this is better:Quote:
Originally Posted by Cioran
No deterministic theory or interpretation can adequately describe QM which is non-deterministic.
There are at least two places where non-determinism enters QM:
1) One source of non-determinism comes from Heisenberg's uncertainty principle where some paired measurements, such as position and momentum, cannot be determined because the order of measuring them does not commute. As I see it this is what MWI attempts to address in QM by replacing the wave function collapse with many worlds.
2) The restriction of matter to quanta rather than allowing it to get arbitrarily small is another source of non-determinism. This is what Born is saying implies that even classical physics is non-deterministic. Eventually the imprecision in the initial state leads to a drift. That is, there is no initial state that works indefinitely. That initial state must always be refreshed and is therefore not deterministic.
It is only an illusion of classical physics that it ever was deterministic.
It is not just the complicated nature of the results. Because of quantum theory, there is ultimately no way to get adequate precision to construct a deterministic theory of reality.Quote:
Originally Posted by Cioran
Any attempt to create a classical Newtonian deterministic explanation is forced to accept imprecision at the quantum level in measuring an initial state. What I learned from Born is that a deterministic solution requires that a single initial state be used to predict the entire future. If such an initial state can be constructed then quantum theory is false.
All physics is non-deterministic, both classical and quantum, because of quantum theory.
As I understand Born, the initial state problem is not contained in the wave function collapsing or not. He is mainly addressing classical physics. It has to do with the imprecision of the measurements of the system. For determinism to work, the initial state cannot change. It cannot be refreshed and because of the imprecision required by quantum mechanics, future results will drift. Eventually, what originally came out as a "seventy percent chance that x will be found located at y" will be calculated as a sixty-nine percent chance that x will be found located at y". Soon the drift from reality will become an issue for technology and then MWI will be rejected.Quote:
Originally Posted by Cioran
The ontological consequence is that the stuff of reality is inherently non-deterministic. Because MWI is deterministic, it does not describe reality. Therefore, the MWI has no basis in reality on which to make an ontological claim that many worlds exist.
Btw, mal4mac, since you are interested in Internet chess, you might be interested in David Deutsch’s multiverse chess. From the article:
Then follow the correction and the correction to the correction.Quote:
Thus a single quantum processor, with the same clock rate as one of Deep Blue’s processors, could examine a trillion chess positions in one second — and in two seconds it could examine four trillion, in three seconds nine trillion, and so on [see corrections below – DD].
And this (bold face mine; it was italicized by Deutsch for emphasis in the article but since all pulled quotes here are italic, I bolded it instead):
Quote:
To predict that future quantum computers, made to a given specification, will work in the ways I have described, one need only solve a few uncontroversial equations. But to explain exactly how they will work, some form of multiple-universe language is unavoidable. Thus quantum computers provide irresistible evidence that the multiverse is real. One especially convincing argument is provided by quantum algorithms — even more powerful than Grover’s — which calculate more intermediate results in the course of a single computation than there are atoms in the visible universe. When a quantum computer delivers the output of such a computation, we shall know that those intermediate results must have been computed somewhere, because they were needed to produce the right answer. So I issue this challenge to those who still cling to a single-universe world view: if the universe we see around us is all there is, where are quantum computations performed? I have yet to receive a plausible reply.
That's what I was saying in a nutshell. Invoking common sense after a century of scientists dealing with QM seems a bit pointless...Quote:
Originally Posted by Cioran
Not that I object to reading Dickens or Plato or Kant, but it seems like you're making this more a matter of personal aesthetic preference than about a desire to understand how reality works. Yes, all we have are predictive models, but that's all we've ever really had to begin with. Our entire brain can only be a map, but never the territory it's representing; in that sense, even our senses don't directly connect us to reality. However, when we're able to use models to predict outcomes, to predict sense experience, it does start to appear as if those models are an accurate representation of something external to our subjective biases, that the map reflects the territory.Quote:
Originally Posted by mal4mac
Yes, I prefer things that give delight to mechanical understanding. If you get most delight in playing with quantum stuff, then fine. I did that for too long perhaps, these days I prefer Sherlock Holmes or whatever classic novel I might be reading at the moment. Novels give me more delight.Quote:
Originally Posted by MorpheusSandman
I wouldn't actually recommend reading Kant, his writing style is not delightful. But I think you are really wrong in thinking you are "understanding reality" in imbibing these models - try reading through the philsophy section of the library, and popular works that take Kant seriously (e.g., anthing by Bryan Magee.) That was probably the main thing that got me off this "reality quest" an dthe much more fun "delight quest".
The map being close to reality stuff is nonsense - try going for a nice country walk on map of the Cotswolds!
So are sunsets or Picasso's paintings predictive models?Quote:
Yes, all we have are predictive models, but that's all we've ever really had to begin with....
They work in a limited context, but like Socrates said, "we know nothing", translated: "we can't know the truth". And that's because as MS pointed out, we are apes, not Gods.Quote:
Originally Posted by Cioran
Poor baby. The way his supporters complain you'd think he'd joined Bruno on the Inquisitions' stake.Quote:
He was driven out by negative ad homimen attacks that soured him on academia in general.
The basic ideas of the truly great minds, Einstein, Feynman and Bohr, say, should be. The rest, why bother... At school, and even University, only the truly greats *were* mentioned! No mention of Everett, or the other wacky interpretations. So the school system, backed by the mass of academia, agrees with me...Quote:
So something that has captivated the greatest minds in science for a century is not something that should be part of anyone's general culture? I suggest you speak for yourself.
In the Biblical model, and everyday experience model, the Sun does go round the Earth. The Newtonian model works better for sending things to the moon, and the like.Quote:
Is true that the sun goes around the earth, or is it false? Once you admit it is false, then your whole argument that all we can have are models, and that there is no "true way" the world "is," fall to pieces, doesn't it?
I think people should be talking about what stuff should be talked about.Quote:
Not at all. You keep complaining that people should not be talking about this stuff. So why are you still talking about it?
Besides the Copenhagen and Many Worlds Interpretations, there is also the Penrose Interpretation which may offer a way for gravity to get involved with QM: http://en.wikipedia.org/wiki/Penrose_interpretation
This is an "objective collapse theory". It still has indeterminism. Penrose claims that particles can be in more than one place at a time yet lose that ability as the gravitational stress goes beyond one "graviton". He also describes an experiment to test his theory.
What I find interesting about this is the inclusion of general relativity in QM. It also makes some sense out of the superposition of a particle in more than one location. And he outlines an experiment to test the theory. To my knowledge the experiment has not been run.
This would be an alternative to MWI that would explain the superpositions prior to wave function collapse avoiding the need even at that stage to conjecture the existence of other worlds. A particle being at more than one location would be explained by gravity rather than the existence of other worlds in which it exists simultaneously.
The ancient Greeks were sharp cookies. Unfortunately most of their best guesses were wrong. We've moved on since Socrates. Also, you seem to have missed the post where MS was confirming that his point supported my argument, not yours.Quote:
Originally Posted by mal4mac
That's not true. Everett and his work is in the forefront today. Stephen Hawking is a Many Worldist, for example. So is David Deutsch, the theoretical physicist and founder of quantum computing. Deutsch is still waiting for you (or someone) to answer a simple question: If superposition calculations are taking place that produce a result -- calculations being a physical enterprise involving matter and energy -- then where are they taking place? If they are not taking place in parallel worlds, then they are simply magic! Like saying God did it!Quote:
Poor baby. The way his supporters complain you'd think he'd joined Bruno on the Inquisitions' stake.
The basic ideas of the truly great minds, Einstein, Feynman and Bohr, say, should be. The rest, why bother... At school, and even University, only the truly greats *were* mentioned! No mention of Everett, or the other wacky interpretations. So the school system, backed by the mass of academia, agrees with me...
Does the sun orbit the earth, or not? Are you seriously trying to suggest that you don't know the answer to the question? Because once you answer it, of course, your suggestion that all we have are models, and as apes we are foreclosed to knowing reality, is kaput.Quote:
In the Biblical model, and everyday experience model, the Sun does go round the Earth. The Newtonian model works better for sending things to the moon, and the like.
Who appointed you the arbiter of what people should and should not talk about? The conceit of this pretension is breathtaking. Again, if you find this topic uninteresting or futile, then absent yourself from the discussion. To try to dictate to others what they should and should not talk about is rather repellant, IMO.Quote:
I think people should be talking about what stuff should be talked about.
I think interpretations such as the one Penrose presented would explain where quantum superpositions occur: They occur in the real world. There is no need for other parallel worlds.Quote:
Originally Posted by Cioran
E-mail Deutsch and see what he says. Maybe he'll even joint this discussion if we're lucky.Quote:
Originally Posted by YesNo
Newtonian mechanics is a false theory.Quote:
Originally Posted by mal4mac
I did! In the "everyday" model the sun orbits the Earth and the Earth stands still and the Earth is flat.Quote:
Originally Posted by Cioran
In the Copernican, Kepler, and Newtonian models the Earth orbits the sun.
I'm not trying to force anyone, and how can I dictate anything? I can't get my Inquisition torture equipment down the internet superhighway. Why can't one question how interesting a topic is? Anyway, you're the one keeping the conversation going, if you find it repellent then stop conversing!Quote:
Who appointed you the arbiter of what people should and should not talk about? The conceit of this pretension is breathtaking. Again, if you find this topic uninteresting or futile, then absent yourself from the discussion. To try to dictate to others what they should and should not talk about is rather repellant, IMO.
I'm reading his The Fabric of Reality hoping to find out more precisely what WMI is attempting to say. Chapters 2, 9, 11, 12, 13, and 14 are supposed to be related to QM. So far from chapter 2, I understand that interference patterns are supposed to be the evidence for parallel worlds visible within each of the worlds. Penrose has a more interesting explanation for this paradoxical behavior of quantum particles based on gravity. That may not be verified, but I think something along the lines Penrose is considering will be found and verified. The parallel worlds idea appears too arbitrary a solution for me. I might as well say fairies do it.Quote:
Originally Posted by Cioran
Does the sun actually orbit the earth, or not? You really don't know the answer to the question? I suggest you are being evasive because answering correctly "no, the sun does not orbit the earth" undermines your argument that all we have are models. Do you seriously expect us to believe that you think the question of whether the sun orbits the earth is undecided or undecidable, because in some models it does and in others it doesn't? If that really is your answer, it's the exact same answer the Church gave some 400 years ago and which brought Galileo before the Inquisition.Quote:
Originally Posted by mal4mac
You're confused again. It's you who finds the conversatin repellant, yet for some reason you keep conversing. I said that what I found repellant is how you set yourself up as arbiter of the things that should and should not be discussed.Quote:
I'm not trying to force anyone, and how can I dictate anything? I can't get my Inquisition torture equipment down the internet superhighway. Why can't one question how interesting a topic is? Anyway, you're the one keeping the conversation going, if you find it repellent then stop conversing!
I finished chapter 2 of Deutsch's The Fabric of Reality and I think I can describe an experiment that could be constructed to test whether there are parallel worlds or not.
According to Deutsch, when photons interfere in the double slit experiment there are tangible photons and shadow photons involved. The tangible photons are the ones that the experimenter sees and the shadow photons are in the parallel worlds. They only interact to make the interference phenomenon work. Otherwise, they cannot be detected.
What that means is that these worlds must be synced together so that the interference can occur or not occur depending on whether the experimenter opens both slits or covers one of them up. Deutsch claims this about parallel universes (page 51):
It is the explanation--the only one that is tenable--of a remarkable and counter-intuitive reality.
I think Penrose has a way to consider photons being in two places at once without requiring parallel universes, so this is not the only tenable explanation regardless of Deutsch's claim. If Penrose is right, his approach would also lead to a deeper understanding of the universe and not just compound the counter-intuitiveness of reality.
But in any case the many worlder's need an experiment to prove that these other universes exist. I think the following would work.
Shine a single photon through a double slit until it reaches a photomultiplier that will signal a computer to generate a random number. This random number will be the seed to a series of random numbers that will either cover the second slit or open it depending on whether the random number is even or odd. If the slit is covered there should be no interference. If the second slit is open, interference should be detectable. Set up a mechanism to automatically register whether the interference pattern occurred when it was expected to occur or not and look for a situation when the interference pattern was missed. Automate the test so it can be repeated as rapidly as possible to generate many tests results.
If there really are other universes the interference pattern should be missed every now and then. That would be the proof that the many worlds exist although it would contradict the double slit experiment's expected results.
If the interference pattern is never missed the many worlders then need to explain how this counter-intuitive synching process occurs. That would not prove they are wrong, but it would make one wonder what difference it makes to compound a simple counter-intuitive observation with an explanation that is way more counter-intuitive and which cannot be detected by experiment.
Why? I don't follow your logic here.Quote:
Originally Posted by YesNo
Regardless of which interpretation of QM is correct, if any, the wave interference pattern always appears when the experimental setup is right. That's part and parcel of the theory, and if the wave interference pattern failed to appear, QM would be a false theory.
I agree with that. If this test actually showed a miss on the interference pattern it would show that QM is false and WMI is correct for some other theory, not QM. The interference pattern should always work correctly if QM is correct.Quote:
Originally Posted by Cioran
But if it works correctly, and it involves a syncing with parallel universes, how does this syncing occur? Deutsch doesn't provide any information on that at least so far. What the experiment is trying to show is the existence of these other universes by seeing if the syncing fails occasionally. I'm looking for a validation that these other worlds actually exist that is stronger than Deutsch just insisting it is true.
What evidence is there that these other worlds exist? The interference patterns are not in themselves evidence. They are what one is trying to explain.
------ added
There would also be a concern if the syncing process occurred faster than the speed of light or if these other universes occupied the same space-time location.
If these universes were in the same space-time location so that there is no distance between them, that seems to be as counter-intuitive as claiming a photon can be at two different space-time locations at one time.
If they were at different space-time locations is the information that allows them to sync traveling between the different universes going faster or slower than the speed of light?
I'm not sure what you mean by synching, but just briefly (no time for larger points now), Deutch's evidence is not that he simply "insists that it is true." His evidence is the fact that quantum computation is a physical process that can employ resources many times greater than available to our visible universe. They are real, physical processes involving mass and energy. Where is this stuff coming from, if not from the many worlds? That is his question.