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Post by speakertoanimals on Sept 10, 2010 15:26:28 GMT 1
Perhaps you can explain how a particle can spin both clockwise and anti-clockwise at the same time? I expect that you cannot. And what is this other than the usual 'nothing can be in two places at once' (commonsense innit!), therefore quantum theory is all crap, non-argument that you commonly get from various trolls on various discussion boards. Sorry that this one has descended to such after such a short time............... Actual answer - what some people term a valid 'explanation' is one that fits in with their commonsense - except that our commonsense is based on our everyday experience of objects that behave classically, hence does not apply when it comes to stuff that has already been defined as being non-classical.
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Post by Progenitor A on Sept 10, 2010 15:42:39 GMT 1
Perhaps you can explain how a particle can spin both clockwise and anti-clockwise at the same time? I expect that you cannot. And what is this other than the usual 'nothing can be in two places at once' (commonsense innit!), therefore quantum theory is all crap, non-argument that you commonly get from various trolls on various discussion boards. Sorry that this one has descended to such after such a short time............... Actual answer - what some people term a valid 'explanation' is one that fits in with their commonsense - except that our commonsense is based on our everyday experience of objects that behave classically, hence does not apply when it comes to stuff that has already been defined as being non-classical. As I expected, you cannot explain Still abuse is a good standby, isn't it?
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Post by abacus9900 on Sept 10, 2010 15:50:05 GMT 1
Quantum mechanics is not simple.
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Post by mak2 on Sept 11, 2010 9:48:46 GMT 1
"Perhaps you can explain how a particle can spin both clockwise and anti-clockwise at the same time?"
Think about it this way. Physicists do the maths and then they try to create a mental picture. But the picture is sometimes misleading, because it is derived from their experience of things like particles and spin that exist on the human scale. On the atomic scale, things are different.
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Post by abacus9900 on Sept 11, 2010 9:55:51 GMT 1
"Perhaps you can explain how a particle can spin both clockwise and anti-clockwise at the same time?" Think about it this way. Physicists do the maths and then they try to create a mental picture. But the picture is sometimes misleading, because it is derived from their experience of things like particles and spin that exist on the human scale. On the atomic scale, things are different. Perhaps it's just not possible to make a mental picture that is accurate. As you say, things on the atomic scale are nothing like things on the everyday scale and we tend to think in terms of the way our brain has evolved to deal with the everyday world. Maths is the only accurate way we have, I suppose. It's a bit like 'curved space'. Nobody can 'see' curved space yet we know it exists because it has been worked out and measured mathematically. Such is science.
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Post by Progenitor A on Sept 11, 2010 10:21:10 GMT 1
So our brains are incapable of imagining a particle spinning cw and acw at the same time. Small wonder really How do we 'know' that it is spinning in opposite directions simulataneously? Have these contradictory spins been observed? I do realise that QM is often counter-intuitive, but I did not think that it embraced the impossible
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Post by rsmith7 on Sept 11, 2010 10:48:17 GMT 1
My knowledge of QM is pretty close to zero but I've read Hawkings books and just about followed what he's getting at. My impression is that QM is a series of explanations that fit observed or partially observed phenomenon and these explanations cannot be tested. Each untested explanation is then used as a sort of pseudo law that other explanations have to fit and on it goes. What if one of the early pseudo-laws are wrong? Wouldn't it follow that any subsequent explanations will be exponentially wrong. Be gentle with me, I'm a novice.
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Post by abacus9900 on Sept 11, 2010 10:52:41 GMT 1
So our brains are incapable of imagining a particle spinning cw and acw at the same time. Small wonder really How do we 'know' that it is spinning in opposite directions simulataneously? Have these contradictory spins been observed? I do realise that QM is often counter-intuitive, but I did not think that it embraced the impossible naymissus, the fundamental problem with scientific observations is that the thing you are observing gets 'disturbed' by the the very act of observation itself. This means that in reality it is impossible to observe things (especially at the atomic level) as they would be 'undisturbed', so that the net result of any observation is a combination of the object itself plus any disturbances we have introduced into the process. Also, we need to remember that from the moment we become aware of an observation there has been a chain of events from object to subject (us) that any observation has undergone and which ends up as a conscious experience by the observer and this includes the mediation of scientific instruments. So, what it is exactly that HAS been observed in the final analysis is open to interpretation. One could legitimately say that, from a philosophical point of view, reality is not all 'out there' but is a combination of that and us, which (I believe anyway) makes the universe a 'participatory' universe with conscious beings central to its very existence.
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Post by Progenitor A on Sept 11, 2010 12:59:35 GMT 1
naymissus, the fundamental problem with scientific observations is that the thing you are observing gets 'disturbed' by the the very act of observation itself. This means that in reality it is impossible to observe things (especially at the atomic level) as they would be 'undisturbed', so that the net result of any observation is a combination of the object itself plus any disturbances we have introduced into the process. Also, we need to remember that from the moment we become aware of an observation there has been a chain of events from object to subject (us) that any observation has undergone and which ends up as a conscious experience by the observer and this includes the mediation of scientific instruments. So, what it is exactly that HAS been observed in the final analysis is open to interpretation. One could legitimately say that, from a philosophical point of view, reality is not all 'out there' but is a combination of that and us, which (I believe anyway) makes the universe a 'participatory' universe with conscious beings central to its very existence. Yes I fully understand the problem of meaurement or observation changing the thing that is measured or observed. Measuerement in electronics have that problem I can also understand that QM is very strange and difficult (quite easy to understand that) One of the trouble is, I suspect, language. For example someone has said that some perticles spin in all directions simlutaneously. We all know what spin is so can imagine this particle spinning. We all know what cw is and can easily picture the particle having such a spin. But our language fails us when we say that it spins both cw and acw simultaneously. We know that that is impossible in a unified particle So the language we use does not describe what is going on. Something outside our experience is happening and we use familiar languag in an attempt to describe an unfamiliar thing. That is one of the reasons why mathematics is such an important language. It can express concepts that are outside our language and experience. But, frankly, I do not know of any sceintific concepts outside QM that are not susceptible to analogy in everyday language. OK some of those analogies are convoluted and they are never quite true, but they do aid understanding. This is not true of QM. It seems to be the preserve of a cabal of high priests speaking to one another in a language most of us do not understand. They cannot be blamed for that, but QM does need a real communicator, someone who can create analogies that do not contradict our intelligence. Saying that a particle spins in all directions simultaneously is evidently poppy cock; 'spin' and 'simultaneously' must have some undefined meaning in QM Something odd is happening that words cannot describe Anyway that is how I tend to view things I love learning new things and am aching for the secrets of QM to be revealed, but I do not have the language, and those that 'know' are not articulate enough to express themselves cogently. It is appropriate that you should talk of philosophy as that is concerned very much with language and the perception of reality. What is really going on in QM; does QM lend itself to linguistic analysis? Oddly language, communication, has done far more than science in advancing civilisation (whilst not downgrading the enormous contribution of science). Strange that language, spken languagee, should fail us a this important bifurcation of science.
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Post by Progenitor A on Sept 11, 2010 13:19:45 GMT 1
My knowledge of QM is pretty close to zero but I've read Hawkings books and just about followed what he's getting at. My impression is that QM is a series of explanations that fit observed or partially observed phenomenon and these explanations cannot be tested. Each untested explanation is then used as a sort of pseudo law that other explanations have to fit and on it goes. What if one of the early pseudo-laws are wrong? Wouldn't it follow that any subsequent explanations will be exponentially wrong. Be gentle with me, I'm a novice. Join the club RS. I am very ignorant too. Sorry I cannot help
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Post by abacus9900 on Sept 11, 2010 13:22:15 GMT 1
I think what Speaker was trying to say (rather obtusely, I'm afraid) is that a particle's spin has a potential of being this way, that way, or whatever way depending on when it is measured by a scientist. This is where the probabilistic aspect of QM comes in inasmuch as that you can never predict what the spin will be for certain, only make a guess based on probability. The deeper implication of this though is that the particle does not actually possess a spin until it is looked at, so to speak, so that an observer is necessary for particles to even have any spin or in fact to be a particle in the first place.
I think this does illustrate that we are really like a blind man with a stick. All that can be done is to use our 'stick' to probe whatever it is 'out there' and map what we think of as 'reality' via the reactions of our stick to whatever it 'touches' and be content with the fact that it's only ever possible to 'analogize' phenomena using our inherent mind skills. Even mathematics is an analogy, in the final analysis.
Following from the foregoing, I don't think it is going too far to come to the conclusion that the world we all experience, both day to day and in a scientific context, is all a result of 'mind'. It's like the old riddle: If a tree falls in the forest and there is nobody about to hear it fall, does it make a sound?
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Post by Progenitor A on Sept 11, 2010 13:57:54 GMT 1
I think what Speaker was trying to say (rather obtusely, I'm afraid) is that a particle's spin has a potential of being this way, that way, or whatever way depending on when it is measured by a scientist. This is where the probabilistic aspect of QM comes in inasmuch as that you can never predict what the spin will be for certain, only make a guess based on probability. The deeper implication of this though is that the particle does not actually possess a spin until it is looked at, so to speak, so that an observer is necessary for particles to even have any spin or in fact to be a particle in the first place. I think this does illustrate that we are really like a blind man with a stick. All that can be done is to use our 'stick' to probe whatever it is 'out there' and map what we think of as 'reality' via the reactions of our stick to whatever it 'touches' and be content with the fact that it's only ever possible to 'analogize' phenomena using our inherent mind skills. Even mathematics is an analogy, in the final analysis. Following from the foregoing, I don't think it is going too far to come to the conclusion that the world we all experience, both day to day and in a scientific context, is all a result of 'mind'. It's like the old riddle: If a tree falls in the forest and there is nobody about to hear it fall, does it make a sound? Ah! Your explanation makes sense! I think that we should look to you for explanations of thse strange phenomena
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Post by abacus9900 on Sept 11, 2010 16:42:30 GMT 1
Well, many physicists do not bother about the 'meaning' of what they measure as long as it works but I don't think we should 'kid' ourselves that we are capable of knowing any ultimate truths. I also think the 'observer' plays a central role in scientific experiments so that it is impossible to completely isolate ourselves from the outcome of them
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Post by speakertoanimals on Sept 13, 2010 16:15:15 GMT 1
Wrong.
As regards quantum theory, attempts to construct a more-likely sounding explanation of superposition (the particle is in a state where it is spinning both clockwise and anti-clockwise at the same time, or the cat is both alive and dead at the same time)n are totally missing the point, right at the root of quantum theory, that in the quantum world, things are totally different to our everyday world.
Some might attempt to hope that this statement about doing two impossible things at the same time is just a statement about our igniorance -- that the particle is actually doing one, just that we are totaly ignorant of which one it is doing. Except this is wrong as well.
Let's take a simple experiment -- polarized light passing through filters.
A photon that passes the first filter is polarised in the vertical direction. That is verifiable, because however many other vertical filetrs we put in, it passes through. It is vertically polarised in any sensible sense of the word.
If we put a horizontal filter in, nothing gets past. ho hum, we say, two mutually exclusive states it seems.
Except we now put a filter inclined at 45 degrees in between the two.
Now we have an interesting case. Photons that pass A are vertically polarised. Photons then may or may not pass B, and if they do, they are now polarised at 45 degrees. Yet we see that some of these pass the next horizontal filter, and some also pass if we replace the last horizontal filter by a vertical one. The only sensible explanation is that those polarised at 45 degrees are also somehow in a state that is a mixture of horizontally and vertically polarised. Why can't we just say that SOME are horizontal, and some vertical, we just don't know which? Except this doesn't explain what happens if we replace the last filter by another at 45 degrees, where all photons pass.
So, something that is definitely polarised at 45 degrees, by all sensible meanings of definite, is also somehow a mixture of horizontal and vertical, states that we started off describing as mutually exclusive.
It is okay in the classical case --light is waves and the amplitude jjust gets reduced each time it passes a polarised at an angle.
But with light as discrete particles, the fact that we only ever observe a whole photon, not half a photon, means that these photons have to be in a combination of what we would have previously described as mutually exclusive states.
This isn't explaining anything, this is just describing what we have observed from experiment. We can't logically just chose to ignore it, or pretend that it isn't so, not when all experiments that have been performed keep telling us that the only way to think about this and get the right answers is that a particle can be in two mutually exclusive states at the same time.
No good protesting that it doesn't make sense, or that since no one can explain to you how this is possible, so it can't happen -- according to every experiment that has been performed, it DOES happen, and all other attempted explanations have fallen by the wayside as being in disagreement with experiment.
We are stuck with it -- don't blame me, blame the universe!
Of course, many people tried to refute this daft idea, proposed other more sensible explanations, more experiments, but they were proven wrong, simple as that, and the only explanation that kept working, over and over again, was the two places at once kind of explanation. That's experimental science for you!
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Post by Progenitor A on Sept 14, 2010 12:00:26 GMT 1
AND ANOTHER THING
IF an electron is in two places at once is the total electric charge (a universal constant, 1.6021765 × 10exp−19 coulomb) DOUBLED or does the individual electric charge on each occurrence of the (same) electron become one half of this universal value?
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