Quote:
Originally Posted by mal4mac
http://physicsworld.com/cws/article/...-breaks-record
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Quote:
Originally Posted by mal4mac
http://physicsworld.com/cws/article/...-breaks-record
The speed of light in a vacuum is constant. When people talk about "the speed of light" in a general context, they usually mean the speed of light in a vacuum. Of course, light is slowed down in a medium, like air or water. That was discovered by Jean Foucault in the mid 19th century.
In 1983 the following SI definition of the metre was adopted:
The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. This defines the speed of light in vacuum to be exactly 299,792,458 m/s. So c is actually constant by definition!
You keep bringing up the issue of authority. But what is authority in science?Quote:
Originally Posted by mal4mac
Authorities are not popes speaking ex cathedra that one has to agree with or one gets excommunicated. Authorities are not saints or angels that one might as well agree with since they obviously made it. Authorities are not avatars or incarnations of the divine. Authorities in science are simply shortcuts.
I can't perform every experiment myself so I have to trust what others have done. They are shortcuts. I can't measure every physical "constant", so I use a reference book or database. It is a shortcut. I am also responsible for the authorities I choose to trust. If I use an out-of-date reference book, database or unreliable individual to get the speed of light, or whatever, it is my responsibility.
What clues would I use to accept or reject an authority? Here are some:
1) If the authority is engaging in partisan activity that I find suspicious, I reject that authority. (This is enough for me to reject people like Dawkins.)
2) If I have found that the authority has misrepresented evidence, I reject that authority. (This is enough to reject the TED science board.)
Regarding the question of whether the speed of light was measured 20 km per second less between 1928 and 1945 should not require any discussion. It either did or it didn't. Since TED appears to have recanted their objections, that is enough evidence for me that Sheldrake was correct on the points of fact.
As far as having "very good reasons" for questioning something, all I have to ask is whether the measurements varied or not. To the best of my knowledge, based on the authorities I currently trust, they did. Even Carroll's chart shows variability.
All you have done is proved Sheldrake's point that questioning whether physical "constants" are mathematical constants is the same as challenging a dogma. Apparently, it is so much of a dogma that to question it earns one scorn from people like Carroll.Quote:
Originally Posted by mal4mac
You are speaking of the world of mathematics, not physics. Mathematics is a language for physics. Physics is not the language for mathematics. The latter could go on and on, on its own. But the imagination without physical knowledge is like a toilet without water. Nonsense. That's why Oppenheimer, Teller, and others involved in the Manhattan project let Einstein go on its own and his letter to the president had only his lonely stupid signature. Einstein was lost in mathematics without physics. He even believed, as stupid as ever, that an atomic explosion could bring about an unending chain reaction. He hardly understood the role of the density necessary for that to happen. He even thought that mathematical equations were eternal and when he was offered the presidency of Israel, he stupidly exclaimed "Sorry gentlemen, but politics is ever changing while an equation is eternal."Quote:
Originally Posted by mal4mac
The "unending chain reaction" possibility was taken very seriously by other scientists, especially Teller. The actual calculation that showed it was extremely unlikely was initiated by Oppenheimer in 1942, who set Hans Bethe to using early IBM digital computers. So Einstein was hardly being stupid.
http://www.metabunk.org/threads/debu...-and-cern.692/
Also calling him "stupid as ever" is really stupid; how was he stupid when he was developing the theories of relativity?
Where does that quote on politics and equations come from? I've seen a similar quote unreferenced on the web. He might have said something like that, but it was probably an on off the cuff response to a journalist. Should Einstein just not speak to journalists? That would be snooty. His considered response to the leaders of the state of Israel was:
"I am deeply moved by the offer from our State of Israel, and at once saddened and ashamed that I cannot accept it. All my life I have dealt with objective matters, hence I lack both the natural aptitude and the experience to deal properly with people and to exercise official functions. Therefore I would also be an inappropriate candidate for this high task, even when my old age didn’t interfere with my forces more and more..."
http://www.lettersofnote.com/2010/02...-einstein.html
Imagine saying that to a journalist, UK tabloids would reduce it to, "Einstein can't deal with people!", so he was perhaps wise to go for waffle about equations and eternity.
Quote:
Originally Posted by mal4mac
He hasn't spoken to anyone in 58 years - or have you put this in the present tense because of a sudden belief in Life everlasting?
He lives on in my mind. I just wish his mind lived on in my mind.
First, I doubt that proving or disproving God's existence is what most scientists are or should be concerned with. There are more pressing issues such as global warming, starvation, illnesses, etc that seem more important in a world that's learned to accept that God's existence relies on belief and not proof for the past two thousand years. That being said, some scientists will still fruitlessly turn their efforts to finding God in God particles and whatnot. If there is a god and he had wanted us to *know* of his existence rather than *believe* in it, wouldn't he have found a way to make himself known to us?Quote:
Originally Posted by cacian
Who are you to say how most scientists should spend their spare time? No government will fund most scientists to do this, so its only ever going to be a spare time activity for most. Campaigning against irrationality seems a worthy way of spending ones spare time.Quote:
Originally Posted by Methexis
The opponents of the idea of global warming are just like Christian believers in ignoring the evidence. They believe there is no global warming so they can can carry on gobbling up the Earth's resources without feeling guilty. Why shouldn't they believe without knowing? Christians do it all the time. There are many crank doctors out there pushing quack medicine that, again, go against the scientific evidence. Why shouldn't they believe in the quack medicine? You don't need to to know, belief is enough, Christians have shown this.Quote:
Originally Posted by Methexis
To oppose irrationality in the pursuit of religious belief is to encourage rational thought in general, and to attack the basis on which irrationality holds sway in other areas.
The "God particle", the Higgs boson, has nothing to do with God, here "God" is used as a metaphor for "of central importance", it's like describing Alexander the Great as "a God amongst men". There is no "whatnot" in which scientists try to find God, unless you want to extend the title of scientist to include Biblical scholars who look for evidence of God in biblical texts (and have found no good evidence.)Quote:
That being said, some scientists will still fruitlessly turn their efforts to finding God in God particles and whatnot. If there is a god and he had wanted us to *know* of his existence rather than *believe* in it, wouldn't he have found a way to make himself known to us?
I like the way Methexis brings us back to the original post. It doesn't seem to me that there is any conflict between science and religion, so there is nothing to win or lose.
However, different religious groups have conflicts with each other.
Some think they are on the side of science and reason and caricature their opponents as not. Looking closer at what these groups mean by science and reason it is clear that science and reason is valuable only as long as it justifies their dogmas. When it doesn't, they have no problem inventing fantasy lands built on ideas such as "many worlds" or "hidden variables" or "determinism's compatibility with free will".
I guess that's fine. The world needs dreamers, but these dreamers slip into irrationality when they start believing that they are better than any other religious group.
That's the only conflict I see going on. I hope whoever wins such conflicts respects the civil liberties of others. Since I don't see that happening, I hope there never is a winner.
Luckily for the rest of us, actual scientists do.Quote:
Originally Posted by YesNo
Evolutionary biology is a belief system? Have you even read Dawkins' books on evolutionary biology? Would you mind pointing to any of the actual science in those books that is wrong, that's merely "part of JUST a belief system" that isn't actually supported by the science? Have you even read one of his "popularizing" books like The Greatest Show on Earth that lays out what Dawkins feels are the best evidences for evolution? Can you name anything in THAT book that's wrong, pseudo-science, that's only "part of a belief system"?Quote:
Originally Posted by YesNo
You seem to like to conflate Dawkins the scientist with Dawkins the philosopher; they are not the same. Yes, Dawkins' philosophy is influenced/formed from his science, but your mistake is in assuming that it's the other way around, that Dawkins' philosophy has somehow tainted his science. I have not seen any of Dawkins' opponents give an example of this, and the reverence for Dawkins within his own field is good evidence against this. If Dawkins was, indeed, skewing the facts of evolutionary biology to fit his philosophy, then other evolutionary biologists would be all over him, as they are other "popularizers" or "appropriators" that use "bad science" for ulterior purposes.
Not you, being neither a scientist, nor an authority.Quote:
Originally Posted by YesNo
All I've seen you ever do is reject authorities that espouse beliefs you don't want to believe. You've already made up your mind on a number of subjects, and you reject every authority that espouses them; just like any religious zealot.Quote:
Originally Posted by YesNo
Dawkins is a perfect example of an authority whom you reject, yet can not even say where/why he's wrong. Someone being biased and partisan does not make them wrong. I'm pretty partisan that the Earth is spherical; Dawkins is pretty partisan that evolutionary biology is factual and that Creationism/ID is bunk. Despite our being partisan, we are both correct.Quote:
Originally Posted by YesNo
This would mean you'd reject every Creationist/ID authority, which is good. :)Quote:
Originally Posted by YesNo
Depends on what you (or anyone) means by "science" and "religion." I'm more inclined to say that religion is in direct conflict with the scientific method. Religion poses questions, answers them, and then never seeks to rigorously test them; this method is completely incompatible with science, where every proposed answer is put to rigorous testing to see how well (if at all) they hold up. Besides that, there are numerous examples of religion making claims about the natural world that HAVE been contradicted by science. The numerous people unwilling to accept evolution solely because of their belief that Genesis is literally true is one example of a direct conflict. The more moderate believers like to say that such views are extremist, but I really don't see how the notion of an unfalsifiable deity is really any less extreme given that it comes from the same source as any other fundamental beliefs.Quote:
Originally Posted by YesNo
Despite your authoritative pronouncements, I can't help but notice you have yet to address the evidence for Many Worlds and the evidence against Copenhagen I posted in our last thread on the subject. Here's my post again that you ignored, which I will continue to copy/paste EVER SINGLE TIME YOU BRING UP MANY WORLDS until you can actually address the evidence for/against these interpretations as opposed to, you know, just claiming that they're fantasies concocted by dogmatic atheists:Quote:
Originally Posted by YesNo
Quote:
I am NOT going to start another Many Worlds discussion with you. You have displayed ad infinitum that you don't even understand what Many Worlds is despite having four different people attempt to explain it to. You never even responded to my list of evidence in the last thread:Instead of addressing these issues, you chose to make the MW/CI issue about the nature of choice, and your Wishful Thinking that choice must exist because you want it to, and that choice can only exist in an indeterministic universe. Until you deal with the evidence above, you're the one believing in "collapse" mythologies in spite of the evidence.Quote:
MW:
1. MW’s first basic claim is that QM works all the way down, which would mean everything is in a state of superposition. So far, this has been confirmed by every test done on molecules with 2424 particles. There is no evidence for a “collapse” that separates the quantum and classic worlds.
2. MW’s second basic claim is that the wavefunction is real, which would mean that we should be able to use it to make the exact kind of predictions we’re able to make.
3. MW is compatible with everything we know about classic physics, the same classic physics that have been consistently accurate in modeling large objects in spacetime. The only exception is gravity; however, in being deterministic, local, and real, MW is at least capable of being reconciled with gravity as we learn more.
4. MW being compatible with classic physics would follow the pattern of a more comprehensive theory subsuming an approximate theory, the same way GR did with Newtonian Physics and modern evolution did with Darwinian evolution.
Compare with CI:
1. CI claims that there is a collapse and that this collapse separates the indeterministic world of QM with the deterministic world of GR. So far, this collapse/split has NOT been found in any tests that have been done, and it is certainly not required in any of the mathematical formulas.
2. CI treats the wavefunction as non-real, and if it’s non-real then we shouldn’t be able to make the predictions that we do.
3. CI is incompatible with everything we know about classic physics.
4. CI being incompatible with classic physics would be the first time in the history of science that a new theory completely contradicted a previous, merely approximate theory. What’s more, it would be the first time that we found that things work differently at different levels, despite the fact that classical physics works exactly like we’d expect if it was QM all the way down.
The ONLY advantage CI has is that it can derive the Born rule, but it does this by assuming things that is has absolutely no reason/evidence for assuming. It’s not all that different than assuming the existence of God to explain lightning before we knew about meteorology and electricity. Sure, it explains lightning, but there’s no reason for assuming its true. What’s more, there’s no reason to assume that MW can’t derive the Born rule as technology, especially quantum computing, advances.
In your last post you even stated the absurdity that: "The world is not divided between the indeterministic quantum world and the deterministic world after some sort of collapse. The whole world allows for indeterminism..." which shows that not only do you not understand MW, you don't understand CI. CI very much DOES divide the world between the indeterministic quantum world and the deterministic macro world; that's PRECISELY what the collapse DOES! It says that an indeterministic wavefunction collapses to a particle that then functions "like a well-behaved billiard ball" as one poet put it. After the collapse, particles DO function according to the determinism of Einstein's GR. It's stunning to me that you didn't know this (although I'm not sure why, at this point, I'm stunned by what you don't know about QM).
This Many Worlds/CI thing always makes me think of bumblebees. The laws of aerodynamics are supposed to make it impossible for bumblebees to fly, but they do. That doesn't mean bumblebees are breaking the laws; it just means our understanding of the laws (or bumblebees, or both) is incomplete.
By the same token, it seems to me that if what we know of quantum physics leads us to conclude that either 1) entire universes somehow spring into being every time anything with multiple possibilities happens, or 2) everything only exists when observed rather than vice versa, then we clearly don't know enough to have any business making guesses in the first place.
That's the science fiction version of Many Worlds. The real version is somewhat different. See here for a good laymen's explanation. The problem is, we already know that particles are in multiple positions. From that, there appear to be only two fundamental possibilities; one is that these superpositioned particles magically, indeterminately, collapse upon observance into the single world governed by the determinism of General Relativity, in which those particles are non-real until observed, and in which their actions can travel thousands of times faster than the speed of light; or that all particles are always in a state of superposition, including the particles that make us up, in which case there are many worlds, and the world we are observing are the product of multiple particles becoming entangled (which explains the observational collapse). Keep in mind that Bell's Theorem already ruled out there being the possibility of hidden variables that could reconcile CI with GR.Quote:
Originally Posted by Calidore
As the above article suggests, it's not that our knowledge of QM is incomplete (if it was incomplete our predictions using it wouldn't be so deadly accurate), the problem is that people can't wrap their head intuitively around the explanation and people don't give up ingrained preconceptions easily. Not to mention that people don't like to think of themselves as being no different than particles. The tests have been done, the results are in, but, much like with many people and evolution, some people don't like the answer, so they keep insisting that we need more testing before we decide. However, given the state of current evidence, the probability of any single world theory being correct is slim to none. Yudkowsky gives an even more thorough, bleaker view of the possibility of any single world theory being correct here. To quote the directly relevant parts:Quote:
You shouldn't even ask, "Might there only be one world?" but instead just go ahead and do physics, and raise that particular issue only if new evidence demands it.
Could there be some as-yet-unknown fundamental law, that gives the universe a privileged center, which happens to coincide with Earth—thus proving that Copernicus was wrong all along, and the Bible right?
Asking that particular question—rather than a zillion other questions in which the center of the universe is Proxima Centauri, or the universe turns out to have a favorite pizza topping and it is pepperoni—betrays your hidden agenda. And though an unenlightened one might not realize it, giving the universe a privileged center that follows Earth around through space would be rather difficult to do with any mathematically simple fundamental law.
So too with asking whether there might be only one world. It betrays a sentimental attachment to human intuitions already proven wrong. The wheel of science turns, but it doesn't turn backward.
We have specific reasons to be highly suspicious of the notion of only one world. The notion of "one world" exists on a higher level of organization, like the location of Earth in space; on the quantum level there are no firm boundaries (though brains that differ by entire neurons firing are certainly decoherent). How would a fundamental physical law identify one high-level world?
Much worse, any physical scenario in which there was a single surviving world, so that any measurement had only a single outcome, would violate Special Relativity.
If the same laws are true at all levels—i.e., if many-worlds is correct—then when you measure one of a pair of entangled polarized photons, you end up in a world in which the photon is polarized, say, up-down, and alternate versions of you end up in worlds where the photon is polarized left-right. From your perspective before doing the measurement, the probabilities are 50/50. Light-years away, someone measures the other photon at a 20° angle to your own basis. From their perspective, too, the probability of getting either immediate result is 50/50—they maintain an invariant state of generalized entanglement with your faraway location, no matter what you do. But when the two of you meet, years later, your probability of meeting a friend who got the same result is 11.6%, rather than 50%.
If there is only one global world, then there is only a single outcome of any quantum measurement. Either you measure the photon polarized up-down, or left-right, but not both. Light-years away, someone else's probability of measuring the photon polarized similarly in a 20° rotated basis, actually changes from 50/50 to 11.6%.
You cannot possibly interpret this as a case of merely revealing properties that were already there; this is ruled out by Bell's Theorem. There does not seem to be any possible consistent view of the universe in which both quantum measurements have a single outcome, and yet both measurements are predetermined, neither influencing the other. Something has to actually change, faster than light.
And this would appear to be a fully general objection, not just to collapse theories, but to any possible theory that gives us one global world! There is no consistent view in which measurements have single outcomes, but are locally determined (even locally randomly determined). Some mysterious influence has to cross a spacelike gap.
This is not a trivial matter. You cannot save yourself by waving your hands and saying, "the influence travels backward in time to the entangled photons' creation, then forward in time to the other photon, so it never actually crosses a spacelike gap". (This view has been seriously put forth, which gives you some idea of the magnitude of the paradox implied by one global world!) One measurement has to change the other, so which measurement happens first? Is there a global space of simultaneity? You can't have both measurements happen "first" because under Bell's Theorem, there's no way local information could account for observed results, etc.
Incidentally, this experiment has already been performed, and if there is a mysterious influence it would have to travel six million times as fast as light in the reference frame of the Swiss Alps. Also, the mysterious influence has been experimentally shown not to care if the two photons are measured in reference frames which would cause each measurement to occur "before the other".
Special Relativity seems counterintuitive to us humans—like an arbitrary speed limit, which you could get around by going backward in time, and then forward again. A law you could escape prosecution for violating, if you managed to hide your crime from the authorities.
But what Special Relativity really says is that human intuitions about space and time are simply wrong. There is no global "now", there is no "before" or "after" across spacelike gaps. The ability to visualize a single global world, even in principle, comes from not getting Special Relativity on a gut level. Otherwise it would be obvious that physics proceeds locally with invariant states of distant entanglement, and the requisite information is simply not locally present to support a globally single world.
It might be that this seemingly impeccable logic is flawed—that my application of Bell's Theorem and relativity to rule out any single global world, contains some hidden assumption of which I am unaware -
- but consider the burden that a single-world theory must now shoulder! There is absolutely no reason in the first place to suspect a global single world; this is just not what current physics says! The global single world is an ancient human intuition that was disproved, like the idea of a universal absolute time. The superposition principle is visible even in half-silvered mirrors; experiments are verifying the disproof at steadily larger levels of superposition—but above all there is no longer any reason to privilege the hypothesis of a global single world. The ladder has been yanked out from underneath that human intuition.
There is no experimental evidence that the macroscopic world is single (we already know the microscopic world is superposed). And the prospect necessarily either violates Special Relativity, or takes an even more miraculous-seeming leap and violates seemingly impeccable logic. The latter, of course, being much more plausible in practice. But it isn't really that plausible in an absolute sense. Without experimental evidence, it is generally a bad sign to have to postulate arbitrary logical miracles.
God already won.
God never played the game because s/he/it never existed.
This is not a game. But how could s/he/it be used if s/he/it never existed. Don't be ridiculous. ROFLMAO. Insane case closed.Quote:
Originally Posted by MorpheusSandman
I read this imagining Liam Neeson's voice.Quote:
Originally Posted by cafolini
S/He/It is not used, simply imagined.Quote:
Originally Posted by cafolini
Morpheus: Thanks for the links. Laymen's explanations are what I would need. Even so, on skimming them I think I'll tab and read them later when my brain feels up to it. I do have to say that rhetoric like in the first three paragraphs you quoted tend to make me distrust the writer somewhat. Not to mention that the supporting links in that person's articles are to articles also written by him. Looking past the fact that Eliezer agrees with you, can you recommend his article(s) just on the basis of content minus the sales job, or (preferably) do you have a more neutral source of information?
Yes, it's pure rhetoric. And he calls himself "The Physicist"! Read *actual* books by top physicists, with *actual* names, working at top universities, like Stephen Hawking and Brian Greene. Otherwise how do you know you aren't reading stuff made up by a janitor?Quote:
Originally Posted by Calidore
Those many worlds are just as unfalsifiable as any deity.Quote:
Originally Posted by MorpheusSandman
I'm not an authority, but I'll pick a couple issues to respond to with what I currently think is true:Quote:
Originally Posted by MorpheusSandman
You mentioned in that post that "CI treats the wavefunction as non-real". That is to its credit. That means the "collapse" is just a mathematical tool to get a useful result. The wave function is a way to get the probabilities that a collection of particles will show certain results overall. It doesn't represent a real field or entity. I don't see how that could be evidence for Many Worlds.
You claimed that I wrote: The world is not divided between the indeterministic quantum world and the deterministic world after some sort of collapse. The whole world allows for indeterminism..." I probably did. I don't think the only indeterminism that exists is at the quantum level. That only provides us with another piece of evidence that the universe is not deterministic as we can tell from the evidence of our own experience.
After Bell showed that QM does not allow for determinism and local (slower than light speed) behavior I think it is useful to bunch the different QM interpretations into how they view these two features:
1) Deterministic and Local: This position has been falsified by science (Bell's theorem and the experiments confirming it). It seems as if Many Worlds proponents think they can recover it. This makes Many Worlds unscientific. Failure to derive the Born probabilities confirms that MW is not even an interpretation for QM.
2) Indeterministic and Local: This is where the Copenhagen interpretation as well as the various alternate, consistent or decoherent histories interpretations fit. This is the only position for which there is evidence for matter-energy entities.
3) Deterministic and NonLocal: This is where Bohm's interpretation lies. It presumes superdeterminism. Essentially we are in the Matrix with no Zion-like resistance movement possible, but there is no evidence for this.
4) Indeterministic and NonLocal: I don't know of any QM interpretation that fits in this category. Perhaps consciousness as some sort of "field" could have these properties, but not matter-energy entities. Various psi studies may confirm this or not.
That Yudkowsky article is the final one in an extremely long sequence that begins here. When I first started reading about QM many years ago, I knew a QM mechanics professor online who actually recommended Yudkowsky as a good, free, accurate, online source. While this professor disagreed somewhat with Yudkowsky's confidence in the MW conclusion, he did claim the actual information was accurate. In my subsequent years of reading about QM and talking about it with others even more knowledgeable than myself, I've yet to see anyone note any error in that sequence, even if some do disagree with the "rhetoric." That "conclusion" article I linked to is mostly rhetoric because Yudkowsky is trying to condense all of the information from the sequence and show how it argues convincingly for MW. Most any conclusion from any non-fiction book contains some kind of rhetorical point for which readers are supposed to have the background information in their mind. I just quoted that part because I think Yudkowsky gives a convincing argument as to why the case is so bad for single world interpretations; but, yeah, you kinda have to understand something about QM to even know what he's referring to.Quote:
Originally Posted by Calidore
It also helps to have some background in a few other things to get where Yudkowsky is coming from, especially his version of epistemic rationality informed by Bayes' Theorem. The thing is, there are currently no ways to "test" between CI and MW, that's why they remain "interpretations" and not "theories." However, for Yudkowsky the preference for CI amongst most physicists (though this preference depends on who, precisely, you ask; it seems that MW is just as, if not more, preferred amongst the top-level physicists) seems to highlight for Yudkowsky several fundamental flaws in human rationality, even amongst scientists. For one it seems that even scientists are slow to let go of certain intuitions like there being a "single world," preferring "magical" explanations like the various collapse interpretations (CI is just the most famous) that unnecessarily complicates QM and creates all of these seemingly irresolvable problems. Why do they do this? Probably because one world seems "less weird," and because the collapse interpretations came first.
However, remove our (infamously faulty) intuitions, consider the current evidence on its face, and then apply mathematical logic, there's no question that MW is the preferable interpretation. If you'd like, I could try to explain it to you myself. I usually get compliments on my abilities to relate complicated, esoteric subjects to laymen, and while I would not claim to be an expert, I do think I've read more than enough on this subject to lay out the basic issues and the conflict behind CI and MW. I can do this without making a "rhetorical" case for MW. I will simply explain the fundamental issue, what CI says about it, what MW says about it, and then lay out the problems and evidence with/for both.
Balderdash.Quote:
Originally Posted by mal4mac
1. "Actual books" by "top physicists" are not usually free of rhetoric, because even scientists have their preferred theories/interpretations for which there is no current proof.
2. "Actual books" by "top physicists" are not necessarily the best starting points for laymen, because "top physicists" get to be "top physicists" by impressing other "top physicists" and not necessarily enlightening laymen as to what the hell all these "top physicists" are talking about. Popularizing science is a completely different skill that most "top scientists" don't possess.
3. Based on all my reading of "top physicists," the actual information (ignoring the rhetorical arguments) in both articles I linked to are accurate. Are there arguments to be made against the rhetoric? Yes. In fact, there is one argument on the very site I culled that long quote from here. It's also notable that there are lots of debates going on in the TALK sections of these articles. So, lest anyone feel the rhetoric is too one-side, it's really not.
4. I assume your "janitor" question was a bit of rhetoric itself, though it's easily dismissed the moment one realizes that almost no janitors would even know the terminology being used in these articles and, what's more, one can relatively easy check the information given amongst any number of sources both online and off. It would be one thing for you to claim some kind of authority and then quibble with the actual information or arguments, but you're just committing a blatant reverse Argument from Authority fallacy and have not given one reason to discredit either article or author I linked to.
You've said this many times, I've countered many times, you've ignored many times. The "many worlds" themselves are a consequence of assuming QM works all the way down. The assumption IS falsifiable, and if the assumption is falsifiable, then so are the many worlds. The problem is not that MW is unfalsifiable (it is), the problem is that it hasn't been falsified. A deity is not a logical consequence of any other assumption that is likewise falsifiable.Quote:
Originally Posted by YesNo
The problem is that if wavefunctions were non-real then we shouldn't be able to use them to make predictions. Why? Because if they were just possibilities before observed then they should not translate into predictions prior to observance, yet they do. Cioran tried to explain this in our first thread on the matter. What's more, why in the world is it preferable to assume something for which we see direct evidence for (how particles behave in a double-slit experiment) as NON-REAL? How can non-real entities provide such evidence for themselves?Quote:
Originally Posted by YesNo
Because there's no reason whatsoever to assume the wavefunction is non-real given that we can see the direct effects of it and make predictions based on it. How does a non-real entity do that?Quote:
Originally Posted by YesNo
All of physics and even your chosen QM interpretation disagrees with you.Quote:
Originally Posted by YesNo
This position was falsified by assuming that human observers are outside and separate from the very processes they're observing and, what's more, it assumes the existence of the collapse whose appearance is explained by MW. So, that position was only falsified if we assume the very things that MW questions. Try again.Quote:
Originally Posted by YesNo
Proof you don't even understand your own chosen interpretation. CI is non-local, and can only get around this non-locality by assuming the wavefunction is nonreal; but assuming the wavefunction is nonreal doesn't suddenly make CI local, because you still have the problem of simultaneous measurements affecting others at great distances at millions of times faster than the speed of light. Yudkowsky gives one example in the part of the article I quoted.Quote:
Originally Posted by YesNo
What's more, there is no "evidence" for Copenhagen. There is an observation (probabilistic wavefunctions turn into particles when we observe them) and an assumption made on that observation (observation causes collapse) for which there is no evidence either in the testing or the math, and, what's more, it's an interpretation that conflicts with everything else we know about physics and for which MW actually explains while being reconcilable with everything else we know about physics. Simply put: there is NO EVIDENCE WHATSOEVER FOR A COLLAPSE IN THE MATH OR EXPERIMENTS.
You have a point, but they usually are less rhetorical, and present the other side. If they do not do this they would get into a great deal of trouble from their colleagues, and if they want to keep their reputation as physicists they have to present a balanced overview. Here's an example from a top physicist, Sean Carroll, who actually prefers the many worlds interpretation, but presents a balanced perspective, even highlighting that more physicists prefer the Copenhagen interpretation:Quote:
Originally Posted by MorpheusSandman
http://www.youtube.com/watch?v=ZacggH9wB7Y
He slips into rhetoric, for a moment, when he suggests that his fellow physicists might not have thought through the issues as completely as he has. (His Copenhagen pals would just smile at that, and accuse him of being a "bit naughty", knowing fine well that this is rhetoric!) But note, he's careful not to say his fellow physicists are "just wrong", because they aren't, and he doesn't want to be thought of as a crank.
That has not been my impression; Albert Einstein, Stephen Hawking, Steven Weinberg, Richard Feynman and Brian Greene are probably the best popularisers I've read, and they are certainly top physicists! The average science journalist just doesn't know enough physics, and are always getting things wrong, so you can never know if you are getting the correct overview unless it comes straight from the top guys.Quote:
2. "Actual books" by "top physicists" are not necessarily the best starting points for laymen, because "top physicists" get to be "top physicists" by impressing other "top physicists" and not necessarily enlightening laymen as to what the hell all these "top physicists" are talking about. Popularizing science is a completely different skill that most "top scientists" don't possess.
So you're happy reading any old web page rather than Richard Feynman? Next time you are ill will you consult an authorised doctor, or use Google and take the advice of "Mr Doctor" on the first page you see? From what you have said previously, you aren't a physicist, so your link is a case of the blind leading the blind up a blind alley.Quote:
It would be one thing for you to claim some kind of authority and then quibble with the actual information or arguments, but you're just committing a blatant reverse Argument from Authority fallacy and have not given one reason to discredit either article or author I linked to.
Both of those articles present the other side, they just present it in an unflattering (but not inaccurate) light. It is a bit ridiculous that you have these two "competing" interpretations, one which has to make all kinds of unnecessary, complicating assumptions only to reach a point where the answer inexplicably conflicts with everything we know about physics (Copenhagen); and another for which we only have to take what we see at face value and work out the issue from there, and from that we reach a point of many worlds. To want both sides presented as being "equally" likely is like the "rhetoric" I see from Creationists/IDers who want their theories presented as being "equal" with evolution even when there is no equality in the evidence. It's true that the CI/MW issue isn't THAT severe, but the more one looks at it, it's not dissimilar. I think both of the articles I linked to accurately reflect WHY these two interpretations don't deserve equal consideration.Quote:
Originally Posted by mal4mac
For every top scientist who's also a great popularizer you could name there are probably 50-100 top scientists who could no more popularize than I could eat a crocodile.Quote:
Originally Posted by mal4mac
What makes you think I haven't read both? I started with Yudkowsky; I've moved on; I still think Yudkowsky is as good an intro as there is.Quote:
Originally Posted by mal4mac
However, you shouldn't mistake professionalism with actual knowledge. My profession is online poker; there are lots of non-poker players that know far more about the game than I do (they teach/write books about the game). Similarly, I am not a film professor, yet I know far more about film than a great many films professors because I've spent more time studying film than most film professors do. One of the perks of playing professional poker is I have lots of free time, because I don't use my profession to live a lavish lifestyle, but to allow me to indulge in my other non-expensive passions like reading, writing, learning, etc.
Yudkowsky is, by profession, an AI Researcher. His profession has lead him into a great many related but tangential areas including QM. The fact that no actual physicist I've talked to has noted a mistake in his series, along with the fact I haven't read anything from any actual physicist, like Feynman, that contradicts anything in his series, is good enough for me that it's accurate.
It doesn't hurt that I also subscribe to Yudkowsky's philosophy of epistemic rationality based on Bayes' Theorem. Most don't even know what those things are so many of his posts come off as being one-sided rhetoric. If people were perfectly rational there would be no need for rhetoric. The rhetoric exists because people aren't rational. In fact, LessWrong is primarily a blog about refining the art of rationality, which basically requires unlearning almost every instinct/intuition you have about life/reality and becoming aware of the manifold cognitive biases that afflict human brains. If you did that, and read through the QM sequence, you'd come to the conclusion that MW was the best interpretation without the need for any rhetoric.
I watched this video. Besides Carroll's affability, which may give the impression of him presenting a "balanced perspective," I don't really see anything in that video that's balanced. He gives the poll data, he goes on to explain MW, to highlights some reasons why he prefers it (it's simpler, resolves itself with classic physics, removes the unnecessary assumptions of CI); then he talks about the poll data and makes the basic claim both Yudkowsky and the "Ask a Physicist" physicist make: that CI makes no sense and is only accepted by people who don't think about it. So, to repeat, I'm not sure what you see as "balanced" about the video...Quote:
Originally Posted by mal4mac
PS, I liked Carroll's analogy about KNOWING VS DOING (race car drivers VS mechanics) and how that helps explain the poll data. I was making essentially the same point above regarding professionalism VS knowledge. Lots of professionals know less about their profession than those that simply write about that profession. Being a physicist and knowing physics are not necessarily the same thing.
He didn't say that!Quote:
Originally Posted by MorpheusSandman
If you construct a Bayes formula to predict the probabilities, is that formula a real entity or field? Or is it just a formula? I see the wave function as a formula to compute probabilities and it predicts the way a group of these particles will behave. It does not predict the way any individual one of them will behave.Quote:
Originally Posted by MorpheusSandman
I can see having a field of forces such as the electromagnetic field, but I find it hard seeing a field of probabilities.
Are you claiming that MW will bring back both determinism and localism?Quote:
Originally Posted by MorpheusSandman
At one point I thought the experiments verifying that Bell's inequality failed implied that quantum reality was nonlocal, but I don't think that is the case anymore. However, that would depend on there being evidence that matter-energy entities can interact non-locally. Do you have such evidence? If so, I would have to move CI to the Indeterminism and NonLocal category.Quote:
Originally Posted by MorpheusSandman
I agree with mal4mac's suspicions about Yudkowsky. If you would like an atheistic physicist to provide an alternate description of QM and its interpretations, I suggest Victor Stenger, "The Unconscious Quantum", 1995. When he is discussing physics, I find him interesting. When he goes into his anti-religious ranting, I ignore him.
He says, paraphrased, that he thinks the majority accept CI because they haven't thought about it very hard. Of course, he lightens and qualifies this by noting it's his personal opinion (that he believes is true), but that's essentially what he says. In fact, he makes it even clearer when he says, again paraphrased: "that's not to say if you think about it very hard you are lead to MW, but you are lead away from CI. The more people worry about how QM works, the less likely they are to accept CI."Quote:
Originally Posted by mal4mac
What Carroll is really doing is making the distinction between applied physicists and theoretical physicists. Applied physicists don't really care about which interpretation is right, so they don't think about it and merely accept CI because it's, as Carroll said, the one that's most widely taught in the textbooks. Most applied physicists say "shut up and calculate" because what interpretation is right has zero impact on their ability to manipulate QM to practical uses (like, say, in GPS). I suspect that if you polled theoretical physicists only the poll results would be very different, and that's what Carroll means by people who really think about this stuff. Most physicists don't because that's not what they're paid to do.
The numbers we apply to Bayes' are obtained by our observations of real objects/events, just like the formulas we've obtained from QM we obtained by observing how wavefunctions behave. I can't think of any formulas in any science that refer to nonreal things. You say that you "see" the wavefunction as a formula, yet how could we have obtained this formula without the wavefunction being real to begin with? How can you see the effects of something nonreal?Quote:
Originally Posted by YesNo
This is me facepalming... MW already has "brought back" (LOL, where did they go?) both determinism and localism. By assuming QM works all the way down (or up), QM becomes local and determinate.Quote:
Originally Posted by YesNo
The EPR Paradox proved non-locality under CI, but assumed locality under the assumption of hidden variables; Bell disproved the possibility of any variables that could account for the paradox. So, between EPR and Bell you have the proof of nonlocality under CI. Besides the disproved hidden variables, there's no way to get around non-locality in CI. There have been many Bell-like experiments done: http://en.wikipedia.org/wiki/Bell_te...le_experimentsQuote:
Originally Posted by YesNo
However, all of those experiments only prove non-locality under the assumption of collapse. That's the key word/term: ASSUMPTION of collapse. All of those experiments place the observer (us) outside the observed. They in no way conflict with MW. In fact, only MW can explain why we see what we do.
Yet can not point to anything in any of his articles that's actually wrong.Quote:
Originally Posted by YesNo
Ah. Yes, I would rather start at the beginning than the end, thanks. :)Quote:
Originally Posted by MorpheusSandman
However, remove our (infamously faulty) intuitions, consider the current evidence on its face, and then apply mathematical logic, there's no question that MW is the preferable interpretation. If you'd like, I could try to explain it to you myself. I usually get compliments on my abilities to relate complicated, esoteric subjects to laymen, and while I would not claim to be an expert, I do think I've read more than enough on this subject to lay out the basic issues and the conflict behind CI and MW. I can do this without making a "rhetorical" case for MW. I will simply explain the fundamental issue, what CI says about it, what MW says about it, and then lay out the problems and evidence with/for both.[/QUOTE]
I'd rather start at the very bottom, as I have zero interest in arguing one set of complete intangibles over the other. I've asked a couple of times (not of you, specifically) in other threads on this subject if anyone could lay out what's actually known, through verifiable and repeatable experimentation, what we have good reason to believe is true, and what's simply speculation. Or, as I also put it, where the tree trunk of knowledge ends and the branches of speculation begin. I'd also be interested in knowing what we'd need to convert the speculation into fact.
The mathematics is just a tool to describe what is real. It is a map of the territory, not the territory. (I'm trying to quote something I think Yudkowsky wrote.) It's the menu, not the meal.Quote:
Originally Posted by MorpheusSandman
So, overall the many worlds there is determinism and localism, but within each of the those worlds QM must work as it does in our world. Is that what MW claims? Since we can't ever get to a perspective where we can see this determinism and local behavior, what good is it?Quote:
Originally Posted by MorpheusSandman
Yes, I guess a sort of non-locality is present in those experiments, but I was thinking of a non-locality in which one can communicate non-locally, not just influence the results of measurements on the other side of the universe. But I guess that is non-local enough. I think it is sometimes referred to as non-separability. OK, I'll put CI in the Indeterminism and NonLocal category.Quote:
Originally Posted by MorpheusSandman
Since I don't think MW is true, he would be wrong about that. However, most people aren't wrong all the time.Quote:
Originally Posted by MorpheusSandman
No problem. I only quoted the end because it was directly pertinent to what I was talking about. Be forewarned, though, that the entire sequence does contain some maths that even I could barely follow.Quote:
Originally Posted by Calidore
Oh, well, that's rather easy.Quote:
Originally Posted by Calidore
Facts: Particles appear to be in multiple positions at once before we measure them. We call this "superposition" or "the wavefunction." From this state, we can not measure precisely the position or momentum of a particle. We can measure one to a degree of accuracy, but the more accurate we get on position or momentum, the less accurate we get on the other. The mathematics that models the limits of our accuracy is known as The Uncertainty Principle.
What's more, when we make the measurement or observation this "superposition" or "wavefunction" collapses to a particle that then behaves deterministically according to the laws of General Relativity. The simplest and most common experiment done to prove this "superpositioned" state is the double-slit experiment. If you don't want to read the dry Wikipedia page, here's a short video for a Children's Education film that just lays out the experimental results.
Basically, all this boils down to this: When we aren't looking/measuring/observing, particles display characteristics of both particles and waves, at times going through both slits, neither slit, or just one or the other at apparent random. The equation that models this is the Schrodinger Equation.
The above are the basic, essential "facts" of what's known. There are certainly many more facts, but the above is essential first step. Most everything else proceeds from how we look at the above. One can certainly draw most of the fundamental questions from what's NOT known about the above:
1. How can particles before observation display characteristics of both discrete matter and waves?
2. What role does our observation/measurement play in making the wavefunction "collapse" into just a particle that behaves according to General Relativity?
3. What role does General Relativity, our most complete picture of physics on the macro scale, play in quantum mechanics, and why do GR and QM seem to contradict each other?
4. Given the both/neither/one-or-other nature of the wavefunction, is quantum mechanics local or non-local, deterministic or non-deterministic, real or non-real?
To explain the terms in 4., locality in physics is a basic principle that matter can only affect other matter locally and not at great distances. This is well-tested within General relativity, but under the classic view of QM this principle of locality seems to be violated. It gave rise to Einsten's phrase "spooky action at a distance." Determinism and indeterminism are more self-explanatory. Under General Relativity, physics is determinate, meaning that every movement of every physical object can be measured and predicted. QM, because of the unpredictability, seems to violate this, and be indeterministic. One way many interpretations get around this is to assume that the wavefunction is "non-real," meaning that it's only a formula of potential, and doesn't become "real" until observance.
Now for the two major "interpretations" or "speculation" as you would call them.
Copenhagen or CI for short: CI believes in the "split" between the quantum and macro world, that the quantum world behaves via one set of physical laws modeled mostly by Shrodinger and Heisenberg, and the macro world behaves by another, mostly modeled by General Relativity. Observation causes the "collapse" of the wavefunction to a particle. CI is non-local, meaning that particles can affect each other thousands of miles away at millions of times faster than the speed of light; it's non-real, meaning it treats the wavefunction as merely an abstract formula; it's indeterministic, meaning that we cannot predict the position/momentum of particles when they "collapse" to the single world.
Problems with CI: The biggest problem with CI is that it contradicts everything else we know about physics (especially via General Relativity). We also have no apparent reason for why observation/measurement should cause a particle collapse. So CI presents a view that there are these two worlds, the quantum and the macro, that refuse to meet in the middle. Indeed, we don't even know where that middle is; where, exactly, the quantum becomes the macro.
The Infamous Cat: Shrodinger's Cat is, basically, the "macro" illustration of CI. Before we open the box, the cat is both alive and dead (like a particle is both a particle and a wave); once we observe the cat it suddenly becomes alive OR dead, like how once we observe a wavefunction it becomes a particle and goes through only one slit.
Back to some facts: Disturbed by these issues, and before quantum non-locality was known for certain, Einstein, along with Podolsky and Rosen, proposed a thought experiment called the EPR Paradox that proved the non-locality under the collapse interpretation. However, assuming locality, Einstein used this paper to argue that there must be hidden, unknown variables that made QM seem non-local. Later, John Bell published what's known as Bell's Theorem which proved that no hidden variables could account for all of the predictions of QM. So this put an end to the possibility that something we didn't know could resolve all of these issues. QM is definitely non-local under the collapse interpretation.
A Preliminary with Many Worlds, or; A Rose By Any Other Name: I just wanted to note that it probably would've been better if MW had been named after its founder Hugh Everett, like Copenhagen was named after its founder. The term "MW" refers to a consequence of the interpretation, not the assumptions being made. Keep that in mind.
Now, back to the speculation itself:
Many Worlds: MW eliminates the collapse postulate and assumes that QM work all the way down (or up, depending on where you start). This means that the "macro" world we see is just the aggregate of a huge number of particles in certain configurations. MW is real, local, and deterministic. It's real because it assumes the equations that govern QM are themselves encoded into the wavefunction; it's local because it explains how measurements are actually two quantum systems (observer and observed) becoming entangled; it's deterministic because if the wavefunction formulas are real, then the wavefunction is just evolving linearly according to those equations.
With these assumptions, MW explains what is going on in the double-slit experiment like this: put in the language of Shrodinger's Cat, there is a world where the cat is dead and one where it's alive. These two worlds are "interfering" with each other. Once you open the door to look, you too "split" and see an "alive" cat in one world and a "dead" cat in another. However, these worlds are, essentially, already present. The wavefunction is evidence of them "interfering" with each other, and observance is what causes "decoherence" between worlds (rather than collapse). A better way to think of it is like this: you have two quantum systems in superposition (in Shrodinger's Cat those systems are you and the cat). Observaton causes these two systems to "entangle" with each other, and the superpositions "pair off" and "part ways" from their superpositioned state.
Problems with Many Worlds: There is only one problem with MW and it's this: MW can not derive the Born rule. The Born rule is the means by which we're able to make predictions using QM as it gives us the probabilities that any measurement will end up one way instead of another. Under MW, there's no apparent reason why one world would/should be more likely than another. Thus far, there's no explanation that resolves this (that I'm aware of, at least).
I should stress that the many worlds themselves ARE NOT A PROBLEM WITH MW. The correct way to assess the various QM interpretations is too look at what they assume and then look at what problems those assumptions create. Copenhagen assumes WF collapse into a single world; this creates the problem of it being irreconcilable with classic physics without disproving classic physics. MW assumes that everything is REALLY QM; this creates the problem of not being able to derive the Born rule. The actual "many worlds" are just a consequence of MW's assumptions being true. You could say it takes the facts of QM at face value, that particles are really going through both slits/neither slit/one-or-the-other slit because until we, as quantum systems ourselves, become entangled with the particles we can glimpse every possible "world" via the experiment's results.
Conclusions + Some Thoughts
So, one basic question you might ask yourself is this: Is it more weird that we have two contradictory, irreconcilable models for two different "levels" of reality without even knowing at what point one world "segues" into the other, or why our observation causes this "collapse" to begin with (Copenhagen); or is it more weird that all of reality, including ourselves, behaves according to the laws of QM, but that in this reality we don't understand why one reality outcome is more likely than another (Many Worlds).
Another you might ask is how these two basic interpretations* might be tested or falsified or decided between since they are both compatible with the observed test results. I will say one way in which MW is falsifiable: if a split between the quantum and macro world IS ever found, then that would falsify MW, because MW's core assumption is that all of reality is really QM. Such a split would show that, no, there actually ARE two discrete levels of reality. So far, though, we've manage to put over 2000 particles in superposition simultaneously; so, if there is some "split," it isn't to the 2000th (or less) particle. As for the other questions, well, I'll save that for if you want to hear my "rhetoric" ("rhetoric" in this case being my underlying philosophical beliefs, epistemic rationality using Bayes' Theorem, that lead me to vastly prefer MW).
I should also stress that, according to your post, there is really only the "known" of QM (known either via experiments, like the double-slit, or via mathematical proofs like Bell's Theorem) and the various "interpretations" (speculations) on what that "known" means. There's really not anything in the middle unless you privilege some sort of philosophical standpoint. Two examples: if you privilege Occam's Razor, or the idea that the simplest explanations are the most likely, then MW is demonstrably simpler than CI because CI is the interpretation "adding" things (namely, the collapse) to explain what we observe. MW is just assuming what we see is real and that that's what all reality is like. If you privilege human intuitions, then CI probably seems more palatable than the notion that there are other worlds and versions of us in those worlds that we can't contact or confirm in any tangible ways. It's easier to imagine a split between a singular world where there is a "micro" and "macro" level.
*I say two "basic" interpretations because there are certainly others, but most interpretations are off-shoots of either the "collapse" or "decoherence" principles. EG, "Many histories" and "Many Minds" are offshoots of the "decoherence" principles. So, the first step is to think about whether you find decoherence or collapse more plausible, given what both assume and what problems they create.
Hopefully all of this was clear/lucid. If you have any specific questions, just let me know.
Yudkowsky appropriated the map/territory distinction from Alfred Korzybiski. Anyway, you're absolutely right. However, for mathematics to be a map there has to be a territory that it's modeling. If you're assuming the wavefunction is nonreal then there's no territory to model!Quote:
Originally Posted by YesNo
We can't "see" localism and determinism because we ourselves are part of the system we're observing. The mistake MW proponents think Copenhagen is making is removing the observer from the process of the observation. MW says that the observation is an instance of two quantum systems (observer and observer) becoming entangled and ceasing to be in a state of superposition. It's this entanglement that makes MW local (observation can only happen locally); it's the fact that all outcomes are realized that makes it deterministic.Quote:
Originally Posted by YesNo
What I meant is that you can't point to anything in his articles that are factually incorrect. Yudkowsky is making the case for why he feels MW is overwhelmingly more likely than CI. If you want to object to Yudkowsky's sequence, you need to object to one of his arguments that lead to the conclusion "MW is most likely true" rather than just objecting to the conclusion.Quote:
Originally Posted by YesNo
Morpheus: Thanks very much for taking the time to write all that out. I'll no doubt have plenty of questions once I've been able to read it in depth. I do tend to believe in going with Occam's Razor when possible, but I don't agree that necessarily favors MW. MW may have the simplest path, but leading to the wackier conclusion. CI has the simpler conclusion, but it requires taking many liberties to get there. That's why I suspect the truth will turn out to be a "C" choice, whatever form that may take.
You also state further above that if our knowledge of QM was incomplete, our predictions wouldn't be so accurate; I submit (granted, much more uninformedly) that holes in knowledge don't always look like holes until you step on them and start falling. How many times have the space guys been completely surprised by probe findings and had to scrap a whole bunch of ideas that had made perfect sense until then?
I think I have also come to understand your much earlier 80/20 loaded coin example in the context of the weather: When the forecast has a 50% chance of rain, that 50% chance is an illusion; it's actually 80% if you go outside and 20% if you stay in.
You're very welcome, Calidore.
That MW is simpler than CI is one the "facts," not speculations. I mean if you literally wrote out those interpretations as mathematical code, MW would be much simpler because it's not "adding" anything to the formulas that model QM, it's just treating them as real. CI is treating them as non-real, adding the collapse, and then having to face the various problems this creates.Quote:
Originally Posted by Calidore
That a simple starting point leads to a more complex conclusion shouldn't surprise us as that's precisely what we see in nature; simple, fundamental things aggregating to more complex forms. This happens in everything from evolutionary biology to societies to matter itself (quanta aggregate to particles to atoms to molecules). This is why I stressed that you have to judge MW based on the assumptions being made, not where it ends up.
It's not just an issue of accuracy (though it is scary accurate: Feynman once famously said that it's as accurate as predicting the the distance of the width of North America to within the span of a human hair, and that's not really an exaggeration), it's an issue that, as Bell's Theorem proved, no hidden variables could account for all the predictions of QM while maintaining the principle of locality under the assumption of collapse.Quote:
Originally Posted by Calidore
No, that's still wrong. The important thing to understand is that reality has no probabilities. The probability any thing will happen is always 100%/0%. When we humans assign probabilities, those probabilities express a combination of how much we know and don't know about the subject in question. In the coin flip, we know the coin has two sides; we don't know (or can't calculate) the various physical forces that will determine what side it lands on. In the weather example, we know what meteorological situations are most likely to produce rain; but those systems are so complex that we can not perfectly track every development to decide if/when it will, indeed, rain.Quote:
Originally Posted by Calidore
Perhaps a better example than the coin or the weather is a shuffled deck of cards. Once you shuffle a deck, the top card is what it is. If the top card is the queen of hearts, the probability it's the queen of hearts is 100%. However, if we were to assign a probability to the top card being the queen of hearts (without having looked at it), we'd say the probability is 1/52 or 1.9%. That probability expresses both what we know about the situation (there are 52 cards), and what we don't know about the situation (what the result of the shuffle was).
That was actually meant as a joke. :)Quote:
Originally Posted by MorpheusSandman
http://i46.photobucket.com/albums/f1...erious-cat.jpgQuote:
Originally Posted by Calidore
The double slit experiment is really fascinating (electrons as waves or particles?), but there is another famous physical paradox from the field of thermodynamics that is worth considering. That is "Maxwell's Demon." Basically this involves a hypothetical experiment in which we start with two chambers containing gaseous molecules at the same temperature. There is a sort of "gate" that can be opened or closed by a miniscule "demon" in one of the chambers who is able to observe molecules moving around in his chamber. In particular, this demon is able to determine the speed and direction of a molecule approaching the gate, so as to allow, if the demon wishes, the molecule to move to the other chamber by opening the gate to allow its passage to the other side. What Maxwell wanted to know was whether or not the Demon could effect a temperature change between the chambers, for example by allowing faster moving particles to pass through the gate and thus causing an increase in the temperature of the chamber on the other side of the gate.
This is a profound question, and every bit as profound as the question of interpreting the wave versus particle behavior of electrons in the double-slit experiment. Thermodynamic "laws" are essentially "empiric" laws, that we believe are "empirically" true on a macroscopic level. Thermodynamics, like quantum mechanics, depends on "statistical" mathematical analysis to explain the behavior of matter.
Maxwell's Demon involves a "thought experiment." The main conundrum is that if we allow the Demon to be able to control the gate in such a way that he can allow fast-moving particles to enter the "other" chamber, the Demon will violate the Second Law of Thermodynanics.
There has been much discussion about this Maxwell's Demon, and mainly why this Thought Experiment doesn't lead to any physical problems or logical uncertainties...
I think that a way of dealing with the problems of the putative "Demon" involves an appreciation of the fact that the Demon, in order to be able to do what Maxwell wanted him to be able to do, would need to have a certain degree of "molecular organization. The 'organiational complexity" of the demon would have to be figured into calculations of the ability of the demon to "violate' the Second Law.
I guess the demon would be providing an energy source to do the work. http://en.wikipedia.org/wiki/Maxwell's_demon
It does make me wonder how if everything runs down, gets entropy, what is the physical law that allows something to lose entropy overall in a closed system, not just transfer less entropy from one part to the other? Chance isn't going to work here. Chance is what increases entropy.
Getting back to quantum stuff, such as electrons, viewed metaphorically as particles, they don't ever seem to run down. They have to keep moving like a perpetual motion machine. If they did take a break, then we would be able to know their precise position, x, and precise momentum 0, which would violate QM. The particle metaphor breaks down.
The assumptions are tested, "judged", by the logical results, that is, "where it ends up".Quote:
Originally Posted by MorpheusSandman
If one ends up with a logical contradiction, and the chain of reasoning is correct, then one or more of the assumptions is wrong. If one ends up with a conclusion that violates experimental results then one or more of the assumptions, or some reasoning along the way, has to be rejected.
The end results provide the basis for falsifiable tests.
In many worlds nothing seems falsifiable. Do an experiment and in one set of worlds you get one answer. In another set of worlds you get another answer. Why bother?
Well, yes, we often find ways to test assumptions, hypotheses, and theories by where they lead. There's no way to directly observe things like common descent in evolution, but if common descent is true, we expect to see certain things in the fossil record, when we look at DNA of various species, etc., and we do, indeed, see those things. However, this is not always the case. Sometimes the assumptions themselves are directly testable (more on this later).Quote:
Originally Posted by YesNo
What I meant by what I said is that you can't look at the conclusions, the logical results, and say that that conclusion is too complicated, that it's counter-intuitive, that you're uncomfortable with it, etc. and use THAT to argue against the interpretation, hypothesis, or theory. To use my evolution example, if someone proposed the mechanism for biological change we call evolution, it would not be fair for an opponent to say "but, if we take that to its conclusion, that would mean man came from the same place as modern apes" and then reject evolution because those implications either can't be observed, or they make the opponent uncomfortable or they seem counter-intuitive or too complex.
The latter is what has happened with you (and, to be fair, a great many others) regarding Many Worlds. You don't even look at the assumptions being made, you look at the end result (the many worlds themselves) and say that they're unfalsifiable, counter intuitive, and needlessly complex. Just as it's unfair to look at the end result of evolution and argue these things, it's unfair to look at the end result of MW (the interpretation) and argue these things.
YesNo, I've mentioned many times how MW is falsifiable. It's true that we can not test/contact the other worlds, but, following what I said above about assumptions being directly testable, MW's assumptions are falsfiable. MW's essential assumption is that all reality functions according to QM, so there is no "split" between the quantum and macro worlds. This assumption is falsifiable. If we are ever able to put multiple particles in a state of superposition and find that some of those particles are not in that state, then that will falsify MW. CI is all about the "split" between quantum and macro world via the collapse. If all particles are superpositioned, then there is no split, no collapse, everything is QM, and MW is true, and the many worlds themselves are the result of that basic truth. I've also mentioned that, thus far, over 2000 particles have been observed to be in superposition simultaneously, so if there is that split/collapse that CI says there is, it is not to the 2000th or less particle.Quote:
Originally Posted by YesNo
I want to make one more, parable-like point about what I mean by judging MW by its logical conclusion. Here's the parable:
Two extra-dimensional beings discover the existence of our dimension. However, they can not see or investigate too deeply into that dimension. These beings live in a dimension where there is almost a complete lack of matter. In fact, these beings are almost pure, disembodied intelligence, meaning the only matter they're made of is what is requires to produce intelligence. These beings do get a glimpse into the quantum fields of our universe, but do not understand it and doesn't know what it is.
Being 1: Based on our observance, perhaps those fields are really fundamental forms of matter, we'll call them quanta, and that these quanta obey equally fundamental laws that govern their movement. I like this hypothesis as both what they are and what they do are extremely simple and consistent with what we observe.
Being 2: Yes, the matter and movement may be simple, but think about the logical conclusions! If this thing is what you say it is and behaves how you say it does, this simplicity will quickly explode into forms of great complexity, from huge matter-sucking holes, to giant balls of gas, to organic beings with neurological systems! Surely all of this is much too complex, counter-intuitive, and non-falsifiable! I much prefer that we add the notion that it's our observation that's causing the movement and objects we see. In fact, if we don't observe it's not there and it doesn't move! While there's no basis for this in our observance or models, it makes far more sense than proposing that this matter is real and behaves via models independent of what we see, since the end result of that assumption is a universe far too complex, counter-intuitive, and unfalsifiable.
Being 1: Well, that makes more intuitive sense; but, look, we have this screen here. If we turn away from this universe we can observe its affects on this screen. So we can see the affects of this matter and its movement on this mirror without us observing it at all. So far, every time we check its affects, it seems to be and function like we'd expect it to without our observance interfering. So, if your hypothesis is correct, at what point are we supposed to see something different on this screen?
Being 2: No comment.
And now, some light musical entertainment: A Capella Science Bohemian Gravity.
http://www.youtube.com/watch?v=2rjbtsX7twc
That video might be the best thing that has come out of string theory to date.Quote:
Originally Posted by Delta40
I'm sure there are people who question evolutionary descent and natural selection, however, I suspect most people accept those things. It is the explanations for them that cause the problem.Quote:
Originally Posted by MorpheusSandman
For example, did chance plus selfish genes cause all of this? That would imply a smooth fossil record, but the fossil record looks more in line with punctuated equilibrium and the "selfishness" of the gene implies consciousness no matter how one wants to hand wave it out. But why not include consciousness as part of the cause? I don't mean intelligent design, but just intelligent organisms at various levels making choices, some of them working, some of them not.
My point is that disagreements surrounding evolutionary theory are not comparable to the disagreements surrounding MW.
What one ends up with if one accepts MW does not agree with our experience and so one has to ask what is wrong with the assumptions or the logic leading to that conclusion. What one ends up with in evolution and natural selection is accepted. The similarity between species and the strata in sedimentary deposits is easily seen. It is the cause of these end results that leads to the questions.
Let me summarize my objections to MW:Quote:
Originally Posted by MorpheusSandman
1) We have no evidence of MW except what comes from the mathematics of the Schrodinger equation. My understanding of Roland Omnes is that this mathematics does not force one logically to accept many worlds. One world is fine. That means, the mathematics itself, the only evidence for MW, is not adequate to reach a MW conclusion.
2) MW removes the assumption that provides for the Born probabilities, but claims it could generate them. So far it hasn't. As an interpretation, we both admit it is not complete. From my perspective, there is no reason to even consider an interpretation that is not complete.
3) The original objections to Copenhagen's "wave function collapse" have been resolved in Consistent Histories (aka Copenhagen done right) using decoherence theory. So there exists an interpretation that is complete, resolves the issues about "wave function collapse" and does not require many worlds.
4) It is unclear that one could actually split reality in the way MW claims it can be split. True, mathematically one can split the superimposed sine or cosine functions by subtracting them out just as one added them in to the Schrodinger wave function, but can one do that in reality? The experiments showing that Bell's inequality are broken seem to show that these particles cannot be split apart even if one separates them a great distance. I don't see how MW can be local, deterministic and real and still account for the experimental evidence.
I don't follow what you are saying here. There are no "particles". (Nor are there any "waves".) The "superpositions" are only a mathematical model (or, metaphor, like the "selfishness" of genes) that works. In some ways I think the experiments to show that the Bell inequality is broken are the falsification for MW, but MW is so unclear that one can't pin anything on it.Quote:
Originally Posted by MorpheusSandman
Lol. I was hoping somebody would appreciate it!Quote:
Originally Posted by YesNo
A possible solution to the paradox would be to consider that the demon, in order to change the temperature of the two compartments, must be able to perceive the speed and direction of the particles approaching the gate from his side of the chamber in order to "decide" whether or not to open the gate and let them pass to the other side. Lets assume that this precise perception is physically possible (i.e., let's forget about quantum mechanics and completely ignore the Uncertainty Principle, and try to answer the paradox using only thermodynamics).Quote:
Originally Posted by YesNo
Well, the necessary demon would have to be quite small, yet he would also have to be capable of perceiving and making decisions based on what he perceives. In order to do this, it's reasonable to assume that he would have to possess a certain amount of complex internal structure. Now one of the measures of system entropy is the relative structural "complexity." A complexly organized demon would have lower entropy than a randomly organized demon. Since the demon exists, by the conditions of the experiment, in only one of the two chambers, his (negative) entropy would have to be calculated into the entropy of his chamber, and would allow him, without violating the Second Law, to effect a temperature change. His ability to effect the temperature change, without violating the Second Law, would be limited by just how much his "negative entropy value" allows him to raise the temperature of the particles in the "demonless" chamber. This could be calculated. There are other considerations that need to be factored in. A major one is that the demon can't observe particles on the other side of his gate. As he allows more and more faster moving particles to the other side, there will be a greater likelihood that when he opens the gate he will let a fast moving particle back into his chamber. This is a statistical/kinetic issue.
I'm not an expert in physics. I took some undergraduate physics and mathematics courses in college on my way to medical school. I came up with this "solution" to the Maxwell's Demon Paradox when it was presented in one of my undergraduate physics courses more than 35 years ago. I think it offers a plausible explanation for how the demon could effect the temperature change without violating the Second Law, and without having to resort to anything else than classical thermodynamics.