I have read Deutsch's Fabric book and you have given an impressive summary of his main idea - though my memory of the work is quite hazy. As you say his view hasn't had many takers yet but I understand it is becoming more popular among the new generation of physicists. What makes people dubious is precisely the claim that the idea of multiverses splitting off is the *simplest* explanation. Whatever happened to Ockham's Razor?
Re "What's not to like?": Well one thing that might be not to like is that if all these possibilities that fail to make the grade in our world are being actualized elsewhere then doesn't that mean there are worlds where Hitler won WWII (to take the laziest, most hackneyed example)? And so on down the line. In fact(s) there must be innumerable worlds where the inhabitants are living in nightmarish, hellish conditions (but also blissful ones). The theory seems to make all our moral decisions vacuous as even if we do a good deed, "next door" we've chosen the bad option. There's actually something demonic about the idea. Someone (I forget who) wrote a sci-fi book in which the multiworlds quantum theory has been finally proved true and there is a mass outbreak of suicides as people realize that elsewhere there are other "themselves" who made the right career choice, made the right choice of partner, etc, and they can't bear the thought they're stuck in this universe as failures. Re "There's no realism to it, that's the problem": Some might regard that as the beauty of it. Maybe the universe is a work of art in progress. Re: "If something is nothing until we perceive it then what was it before we did if the light that carries the information left the subject before we existed?": OK here are two possibilities: 1) Physicist John Wheeler suggested "backwards causation" - in some way we are pulling ourselves up by our own bootstraps. "We are participators in bringing into being not only the near and here but the far away and long ago." 2) There is one Absolute consciousness (outside of time) that is keeping the whole shebang in order. You might call this Absolute "God" but I don't want to give Barry an attack of acid indigestion. Ask yourself what this *real* world is supposed to be like? Let's stick to one fact - "what is real about this orange I'm about to bite into?". Is it its colour? Nope - my nervous system adds the sense of colour - colour doesn't exist "out there". What about the orange's texture? My sense of touch. Its taste? My taste buds. Its shape? My visual cortex. Its position in space and time? Space and time are our minds' ways of organising our experience (thank you Immanuel Kant). And so on down the line . . . So what is left to your supposed reality? I'll bet the best you can come up with is "structure". Reality must have a structure that matches the structure of my conscious experience (otherwise I'd fall under a bus every time I went to work). But what could be more *ideal* than structure? Someone puzzling over some abstruse theory in pure mathematics is pretty much our archetypal image of what engaging with the ideal is like. If what is real turns out to be information then we are living in a virtual world. ---In FairfieldLife@yahoogroups.com, <no_re...@yahoogroups.com> wrote : ---In FairfieldLife@yahoogroups.com, <s3raphita@...> wrote : Rubbish! The moon is most definitely there when we aren't looking at it . . . So there must be something wrong with the explanation of the theory if it results in logical errors like this. There is no *logical* error - it violates our common-sense beliefs is all. But so did the thought that the Earth is going round the Sun! Try my thought experiment, the idea doesn't work out without violating the speed of light. If something is nothing until we perceive it then what was it before we did if the light that carries the information left the subject before we existed? It's the most extreme example I can think of but it applies to everything. It's the laws of physics that is violated here and not our beliefs about it, so the explanation must be wrong. There's no realism to it, that's the problem. Either there's another principle operating that we don't know yet or everything else we know is wrong and as it all makes sense there isn't any good reason to chuck it out because of an early misunderstanding from a new branch of physics. Classical physics can't help because the nature of the experiment changes the outcome so it was assumed that things are in an indeterminate state when they aren't being measured. And how can they be in a determinate state if our observation changes the result? It's how these experiments are set up, you have to isolate a particle and let it do something, the start and end points can be measured but not what happens in between without changing the nature of the experiment and result. This is what all the various theories are competing to explain and where a lot of physicists claim it can't be explained and they just get on with it. But there are a few ideas that don't involve the sort of problems outlined above. But not every physicist accepted the Copehagen interpretation and its descendants. Einstein never did." And Einstein was shown to be wrong by the Alain Aspect experiment. I remember reading about it but will have to check but that involves time I don't have this morning. The above quote isn't from me and there's be a good reason Deutsch included it. See below. Deutsch maintains that the multiverse explanation is the only one that ticks all the boxes and leaves us with no spooky woo woo. Well, believing that the world splits into many alternative worlds every second - all of them equally real - is as close to woo woo as any new-age drip could hope for. Ah, the million dollar question. Do we live in a multiverse and if we do is there anything weird about it? Weird in the sense that I mean it, things that violate the laws of physics and allow for quantum consciousness memes like the ones that infest the internet. If you want the simplest explanation for all the apparently odd behaviour of subatomic particles then this is it. The one Deutsch writes about isn't the same as Everett's but is a refined version that has staggering amounts of universes sharing the subatomic world with each other and using the same particles. So really they are just different aspects of this one even though we can't ever visit them and ourselves there are as unaware of us as we are of them. This answers all the questions about what atoms are doing when we can't measure them because we are seeing a line of sight through multiple possibilities and our histories are copied almost exactly from universe to universe meaning that the interference patterns in quantum experiments that caused all this trouble in the first place are explained by the atoms simply interfering with each other. It takes a bit of getting used to though, at first it seems like an awful lot of extra space (even though there is no more space) just to keep a realist universe intact and that's why no one believes it, not because it doesn't make sense because it does. So you either have a multiverse or a universe that can't be explained without recourse to nonsense when what we want is the simplest possible explanation. The sheer amount of things it explains that we just had to accept as weird behaviour before is amazing, things like quantum jumps, apparent breaches of light speed and the uncertainty principle - all of them disappear and we get left with a nice simple deterministic universe again. What's not to like? So until someone comes up with a better idea that works as simply it's the best bet, not sure if I would actually bet on it yet, but the more I understand the more I agree that it's the best solution. But that's me persuading myself obviously. So it isn't a woo woo explanation because there's nothing odd or that contradicts other known laws. Just the small matter of an near- infinite number of ourselves to cope with, but that gets easier with practice, it's all about atomic histories and the fungible nature of particles. If we could look closely enough at the cosmic microwave background we could see the moment in the beginning of the universe when it formed. Deutsch intends to prove it. He builds quantum computers that exploit this multidimensional nature of atoms to perform calculations instantly (it's not the only explanation for what's happening BTW) they can't work like a normal computer and can only do certain types of calculation, one of those just happens to be a virtual reality simulation of an atom. Apparently from that they will be able to tell us what they are doing when in their indeterminate state. It's a long way off, but they have achieved some calculations already and all this involves separating atoms from interference and holding them there while others are joined together to form the programme and also without disturbing their state. It's an amazing concept. The future's so bright.... ---In FairfieldLife@yahoogroups.com, <no_re...@yahoogroups.com> wrote : ---In FairfieldLife@yahoogroups.com, <s3raphita@...> wrote : Re "As for quantum states being golden calves, certainly, if you are trying to muck people over with an analogical connection with spirituality": "The stuff that makes up the universe only exists when we observe it" - that quote reflects Bohr's conclusions and sounds to my ears like it ties in nicely with idealistic theories which regard Mind as being more fundamental than any pre-existing external reality. Einstein hated this idea: "I like to think that the Moon is there even if I am not looking at it." Well suck it up Albert - you're wrong. Rubbish! The moon is most definitely there when we aren't looking at it. The alternative to that illogical screw-up from the pioneers is too absurd to contemplate, it doesn't stop them teaching it at university though - at least as a theory. Just suppose the never-before-seen light from a distant galaxy arrives at our eyes tomorrow, what was its starting point before it left? Nothing at all apparently. So there must be something wrong with the explanation of the theory if it results in logical errors like this. And what if two physicists do quantum experiments on each other and compare notes afterwards, did they both not exist? Or just one of them? Quantum physics has got to be the most misquoted and misunderstood branch of science and even by the people who study it, often by them actually. The problem is one of explaining what is happening in certain experiments that show apparent wave/particle duality. Classical physics can't help because the nature of the experiment changes the outcome so it was assumed that things are in an indeterminate state when they aren't being measured. Instead of trying to explain this apparent paradox they just chose to ignore it and concentrate on its predictive power. This is the "shut up and calculate" school of particle physics that doesn't like to ponder what it all means. I'm not kidding. But I can't believe none of them ever wondered what the underlying explanation could be, it wouldn't be human would it? To quote David Deutsch - head of quantum computing at Oxford University - "Niels Bhor said that quantum theory was a complete description of reality. He excused the various contradictions and gaps by using a combination of instrumentalism and studied ambiguity. He denied the possibility of phenomena existing objectively and said that only outcomes of observations should count as phenomena." In other words, he'd rather not think about it. Again, I can't believe he never did, but there are unknown processes occurring between measurements that require an explanation and preferably one that doesn't involve anything counter-intuitive, especially things not existing when we aren't looking at them. The opinions of a generation was set by the fathers of the field though and it's hard to argue against a theory when you don't have a better one. Deutsch again:"It's combination of vagueness, immunity from criticism, and the prestige and perceived authority of fundamental physics opened the door to countless systems of pseudo-science and quackery supposedly based on quantum theory. Its disparagement of plain criticism and reason as being "classical", and therefore illegitimate, has given endless comfort to those who want to defy reason and embrace any number of irrational modes of thought. Thus quantum theory - the deepest discovery of the physical sciences - has acquired a reputation for endorsing practically every mystical and occult doctrine ever proposed. But not every physicist accepted the Copehagen interpretation and its descendants. Einstein never did." Perhaps it's their own fault if we don't get it then. Deutsch maintains that the multiverse explanation is the only one that ticks all the boxes and leaves us with no spooky woo woo, and it really does, he isn't remotely bothered by the fact that only 5% of his peers agree with him. This isn't why I quote him so much but because he cuts effortlessly through the crap of self delusion and bad philosophy. And he is clearly knows his stuff, you'd have to to actually build a quantum computer. This doesn't make him right about his multiverse theory of course, but he articulates the problems with regular QP brilliantly. I recommend his pop science books "The Fabric of Reality" and "The Beginning of Infinity" enormously. Brian Cox is good for common sense and clarity too, here's a quote from him: "There is no spooky woo woo". Last night Jim Al-Khalili presented the first of a two-part BBC documentary called The Secrets of Quantum Physics. He pointed out that the original experiments on quantum entanglement which *proved* that Bohr was right and Einstein wrong was first done by hippie-dippie scientists at Stanford in the early 1970s when they were looking for confirmation of their own (LSD-inspired) beliefs in telepathy and assorted weird stuff. The connection with spirituality is at the very least a helpful analogy - maybe a lot more. https://www.youtube.com/watch?v=Hc1prmRo6x4 https://www.youtube.com/watch?v=Hc1prmRo6x4 Anyway, I wish I'd watched that show now but was so disappointed at the trailer for it that I didn't bother having heard the story so many times. I've even got one of Jim's books, maybe he'll offer an explanation in part two?
