You'll almost certainly get some strong views expressed on this subject by the one who calls himself Xris. Scepticism of the kind you describe about QM uncertainty is his main theme.

One thing I will briefly point out is that other fields of physics don't necessarily require determinism to create accurate reliable theories. A notable example is thermodynamics. The laws of thermodynamics are regarded as among the most solid and reliable in existence, yet they are statistical. The law which states that the entropy of a closed physical system can only ever stay the same or increase is not exact. The entropy could decrease. It's just very unlikely. Whether or not the microscopic world on which these macroscopic laws are based is genuinely deterministic, the fact is that these laws are very reliable simply because they're based on the (effectively) random behaviour of such a huge quantity of particles. Randomness + huge quantities = (effectively) certainty.

Anyway, I'll leave it at that for now. Based on experience of previous threads in similar subjects in this forum, I suspect you've started a fruitful topic here that will quickly fill up with lively debate. Enjoy!

Incidental point: When I raised the subject of thermodynamics (a long way back now) I was making a very general point about how macroscopic laws, based on the statistically averaged behaviour of the microscopic world, can yield extrememly precise and reliable results. I wasn't making a specific connection between thermodynamics and QM. Although of course Statistical Mechanics, unlike the classical thermodynamics of which it is an extension, is actually an example of precise macroscopic laws based on microscopic quantum mechanical behaviour.

Anyway.

This general subject has been discussed before in this forum but I have to say it's a refreshing change to see more people posting comments that are based on actual knowlege of the subject matter and from which it's possible to learn something interesting! Quantum Mechanics seems to be one of those subjects where many people think they see profound philosophical consequences based soley on vague popular accounts which convey the strangeness without the rigour. The strangeness is the fun part. The reasons why this apparent strangeness has been forced on us by observed reality and rigourously tested is harder and is more often skipped.

As Prismatic pointed out, it is an inevitable consequence of the cumulative nature of knowledge that, as the generations go by, it takes more and more work to climb from the bottom to the top of the column of giants on whose shoulders we're all standing (to borrow Newton's analogy.)

To switch to another metaphor: All the low-hanging fruit have already long since been picked. If it was easy for everyone to properly understand the inner workings of nature to the extent that this has been done with QM/Standard Model/Relativity, then it wouldn't have taken so long to develop those understandings. It is an inevitable consequence of greater and greater understanding that people specialise more and more and it gets harder and harder for non-specialists to understand what's being said.

So this is about specialism, not about elitism or dogma. We all have our areas of specialist expertise. I wouldn't presume to attempt a detailed technical debate about the finer points of brain surgery with a brain surgeon.

Having said that, I can see the argument that greater and greater specialism can lead to a kind of protectionism whereby "unorthodox" views could be unjustifiably excluded. When faced with specialist opinion, the standard way for the layman to test that opinion is to get a second specialist with no vested interest in supporting the first specialist, and preferably an opposing interest, to confirm or refute that opinion. The trouble is, the narrower the specialisms get, the narrower the range of opinions within them and the larger the spaces between them. If it turns out that a particular specialism is a blind alley it gets harder and harder for the people in other specialisms to jump that space and challenge them.

And there should be constant efforts to convey specialist ideas to non-specialist audiences. (More popular science books about brain surgery?!?) Otherwise this sense of bewilderment and suspicion, exemplified in this forum by the repeated objections from Xris, can grow. There is already a dangerous widespread non-specialist perception that modern physics is a mathematical fantasy because most people cannot see how these strange abstract mathematical descriptions of nature are extraordinarly hard-won and firmly tied to experimental reality.

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Anyway, on the subject in hand:

The essential message of quantum mechanics is simply that you cannot observe something without affecting it. This truth was not new to QM. We know this to be true in a casual anecdotal kind of way in the human-scale world. But, until QM, we'd always assumed that the effect of the observer on the observed could be made arbitrarily small. In other words, although we knew that in practice we can never completely remove the effect, we thought that for any given level of disturbance, if we require greater accuracy, there is always a way, at least in principle, to make the disturbance smaller.

This was also our belief about the process of measurement in general. As Prismatic pointed out to Xris, whether you're in the "classical world" or the "quantum world", there is no such thing as zero error in measurements. But before QM we had assumed that the error could tend towards zero. It could be made arbitrarily small. Pick any level of error. You could always find a smaller level of error.

We believed these things to be true because, in our experiences so far, they seemed to be true. But there are no guarantees that the patterns in nature will be universal. And so it has proved.

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Xris:

On this thread, you've repeated your usual objections to QM. As I've said before, on a general philosophical point, I think it's important to be clear exactly what we're doing when we make measurements and talk about the entities we think we're measuring.

You've said things like this: "They say that an electron is sometimes like a wave and sometimes like a particle. But what is it? Why can't they make up their minds?"

As I've said, an electron is an electron. It has some properties that remind us of waves and some that remind us of particles. Just as the Sun has some properties that remind us of an orange (shape and colour) and some that remind us of, say, fire (temperature). The concept we refer to as an electron shares some, but not all, of the properties of the concept we refer to as a wave, and likewise with the concept we refer to as a particle. It doesn't share all of its properties with anything else, otherwise it would be that thing.

In practice, concepts like "particle" and "wave" are shorthands for little packages of mathematics that are used to describe the world. Wave-particle duality just means that the full mathematical description of matter contains some of one package and some of the other.

When we make measurements and observations we construct models to describe and predict those observations. Some everyday models are everyday objects like chairs and tables. An electron is no different. It is a pattern in a set of observations. People sometimes say that nobody has ever "seen" an electron or that we can't draw a picture of one and that therefore it is less real than, say, a sandwich. But this is not true. An energy level diagram is a picture of an electron. A Feynman diagram could be a picture of an electron. An equation could be a picture of an electron. It doesn't contain all of the electron's properties, but neither does any picture of anything. If a picture contained all the properties of its subject it wouldn't be a picture. It would be the subject.

This, incidentally, is at the heart of my comments on Bill Gaede's website, to which you drew my attention, and on which I commented in a seperate thread.

He makes a strong distiction between what he calls "concepts" and "objects" which I think you are probably influenced by. I have objections to that distinction.

I, with very little knowledge simply desire an open debate about Gaedes outrageous but feasible alternative but no one appears willing to enter into combat.

Prismatic, for one, listed several specific well defined concrete problems he saw with Gaede's string hypothesis earlier. I created a whole topic devoted to debating Gaede's ideas on this forum a while ago. So I don't really see how you can be justified in saying this.

I must have been on holiday because I never witnessed your opposition.

We have conversed about it. You talked about Gaede and pointed out his website. I looked at his website and commented. You replied. I looked some more, read his paper on the rope hypothesis and created a lengthy topic. We talked about that. And so on. As I said at the time, I tried to ignore the ridicule and cartoons and concentrate on finding something worth a serious look.

But, to be honest Xris, it is now a very well established pattern that you just repeat the same things over and over again and simply ignore replies. I don't want to knock it. All good fun. More meat for our conversational stew. But, technically, not actually a debate!

Xris and Prismatic: If I were you I'd leave it at that. Prismatic has been crystal clear. Xris, you know you will never be convinced by any arguments or evidence, no matter how clearly or patiently explained. I don't see why you need to continue.

But I do think that the general sense of bafflement and suspicion that you've conveyed about most of modern science represents a good point, and possibly the basis for yet another new topic! I suspect it taps into a sense of bafflement and suspicion that a large part of the population feels. It raises, indirectly, the question of how people assess what is true in the absence of understanding and/or information. If we don't have the time to do our own appropriately thorough research or the ability to understand the arguments, how do we decide which competing theories to believe?

Whenever I read a popular science book aiming to convey physics to a non-specialist audience or watch a TV documentary with the same aim I'm struck by the fact that they usually fail to go into enough depth to make a convincing argument unless you already know something about the underlying history of research and theory. We're left with the inescapable conclusion that, in all kinds of fields, we all have to trust specialists. But there are many many people claiming to be specialists. This website is a very good place to observe this. It naturally tends to attract a relatively large number of people who are convinced that they have discovered something profound about the world (or can post a link to somebody else who has).

If you don't have the powers of reasoning, or the knowledge, or the time, to assess their claims, how do you judge them? Some people simply dismiss the mavericks and believe the specialists who hold the prevailing view. Some others go the other way and believe that we're all being lied to all the time. Obviously the ideal is to actually assess the arguments on their merits. But what if you simply can't?

I think I'll start another topic on it if I have time.

Xris:

I love it, I am to be sent to the dunces corner because I do not believe in the quantum scripture.

Not by me, and not by anyone else except yourself. Stop doing the inverted snobbery thing. This is not about intellectual elitism.

Prismatic: That was an interesting story about your former MIT room-mate's obsession with the ether! I guess it's a cliched truth that the geniuses - the people who make the great paradigm changing discoveries - often tend to be obsessive to the point of mental illness. But that doesn't mean that all people who are obsessive to the point of mental illness are going to make a great discovery. Almost none of them will.

So was it you who was Prismatic's MIT college room-mate?

The argument that has been going on here is essentially the same long futile discussion that's happened before on this forum on roughly the same topic. I guess if I was a pessimistic cynical kind of a person I'd say that it exemplifies the futility of establishing any meaningful meeting of minds, using rational discourse, between people with very different ways of thinking. And these discussions happen asynchronously using the written word, giving the participants ample time to consider each other's words, do some research and formulate a reasoned response. Just imagine how much less we could acheive if we were shouting about it over a beer!

Anyway, I'm not a pessimistic cyncical kind of a person. But one thing I have come to realise is that carefully breaking down my interlocuter's words into individual points and then requoting and addressing those points one at a time with rational argument (as valiently attempted in places here) is often a waste of time. People often read what they want to hear and simply ignore what you've actually said. So perhaps it's best just to stick to one simple point and not get bogged down in trying to deal with too much at once.

So here's my simple plea which I think goes to the heart of much of the misunderstanding here:

I strongly advise anybody thinking of saying "I don't believe that X exists" to replace it with the statement: "I don't believe that X is useful". Where X is a concept in physics, like an electron.

I and others have made this point before, and it's been largely ignored, and I full expect it to be ignored again. But what the heck.

Now I'm going to immediately break my own "keep it simple" rule and elaborate:

If we argue over the question of whether or not electrons really exist (for example), then to make any headway we will always have to argue over what it means for something to exist. In the context of scientific investigation, in my view, this will always come down to utility:

What do you want to achieve?

I want to understand how the world works so I can make predictions about how it will behave and use those predictions to arrange bits of the world in such a way that they behave in ways that are useful to me. i.e. technology.

What do you mean by "understand"?

I mean be able to see underlying pattern in my observations of the world that allow me to predict future observations.

So our aim is to "understand" our observations and measurements. To do this, we package them together into sets of observations that appear to be related to each other and we give those sets names like "electron" or "sandwich". And we keep those names for as long as they are useful. Do they correspond to "things" that exist? Don't know. Don't care.

Now the concept of the electron, like the sandwich, was originally invented because it was useful. For example, it helps to describe how cathode ray tubes (televisions) can be made to work. That's useful. Originally electrons were called "cathode rays" but that concept turned out to be less useful and was dropped. Did cathode rays exist? Have they stopped existing and turned into something else? Don't know. Don't care.

"Electron" helps to describe how the electrostatic force on tiny drops of electrically charged oil seems to come in discrete intervals and is not a continuum (i.e. Milikan's oil drop experiement mentioned by Prismatic earlier). It helps to describe why molecules form in the configurations that they do, how the electron microscope works, how the scanning tunneling microscope works, how X-ray machines work, how this computer works, how balloons stick to my pullover.... Actually, it's probably one of the most useful concepts ever invented.

Does that mean it exists? Maybe not. But for something that doesn't exist, it sure is useful. Makes me think that this whole existence thing is overrated.

If we switch the question from one of existence to one of utility I think it becomes much clearer why a concept is retained and what is required of a new concept that seeks to take its place. I presume this is where Gaede's rope hypothesis is supposed to come in. Is Gaede's rope more useful? Should the "electron" concept go the way of cathode rays, caloric and the luminiferous ether?

My main objection to Gaede's rope hypothesis is that it doesn't actually say anything that can be tested. It doesn't even explain what it means by the word "rope". An electron, like a sandwich, is defined as the common characteristics of a vast set of observations. What do diverse observations of little charged oil drops, beams in vacuum tubes, chemical reactions and electron micrographs all have in common? Answer: electrons.

As far as I can see, the word "rope" is being used to signify one of two possible things: (1) a rope (2) an analogy.

If it's number 2 (unlikely, as this violates Gaede's most deeply held principles) then, as has been pointed out by McDoodle, the whole thing seems to be a parody of string theory, with the obvious difference that string theory actually says something empirically true about the real world.

If it's number 1 then you don't need to know anything at all about physics or the world to see that it is inherently logically impossible, because it states that every pair of atoms in the universe is connected by a chain of zillions of atoms. (So little fleas have lesser fleas upon their backs to bite 'em...) The only ropes I and presumably all of you know about are the ones that are made from zillions of atoms, are used to tie things up and stretch according to Hooke's law because of inter-atomic/molecular electromagnetic bonds. If Gaede is using the word to signify something radically different from that then obviously he needs to explain what he means.

I might email him and find out. Although, in all these kinds of encounters, I remember the words of (allegedly) George Bernard Shaw:

Never wrestle with a pig. You get dirty and the pig likes it.

(That is a metephor. I'm not calling anybody a pig.)

--- --- ---

MMfiore, old chum, you said this in an earlier post:

Since dark matter is supposedly 84% of the Universe then our solar system should be composed of 84% of this same material substance. So why don't we see an effect. Our calculations for the orbits around the sun work perfectly with the masses of the sun and the planets just as they are. Hmm... Why is the additional 84% dark matter not affecting the orbits in this solar system? One would have to assume that since the rest of the Universe is composed of 84% of dark matter then we should have that same amount distributed in our solar system. Yet there is no evidence of it here.

I suspect that Prismatic's ridicule stemmed from the fact that you appear here to be puzzled as to why 84% of the solar system is not dark matter. The research you cite was not about the constituents of the solar system. It was, as you yourself have now pointed out, about the distribution of matter within a few thousand light-years of the solar system.

Your assertion that the proportion of dark matter in the solar system should exactly mirror the proportion of dark matter in the universe as a whole, is clearly without any basis. Why should it?

It certainly is a prolific thread isn't it! I'm preparing my latest pearl of wisdom now, but by the time I post it I suspect the comments to which it is supposed to be a devastating rejoinder will be several pages back and lost in the march of progress.

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Xris:

I know, you know, I know, you know, well thats what you have led me to believe, there are no such thing as an electron particle, it is just concept drawn from observation. It acts like a particle so it must be particle. The problem only arises when it becomes a quantum question. When it can not decide if it is a particle or a wave.

You're still using "existential" language, like "there are no such thing" when trying to describing what you think I've said. So you obviously either don't understand or don't buy into what I've said about utility. Fair enough. No law says you have to.

I didn't say there are "no such things" as electrons or particles. I said that, in trying to understand the world, the most fruitful way to think of these concepts is as useful models for explaining observations.

"Particle" is a collective term for a set of properties. "Wave" is a collective term for another set of properties. "Electron" is a collective term for a set of observations that have some properties of...

I'm going to stop there. I've said this stuff over and over again, including lengthy threads devoted to it. There's no point repeating it.

If you do not believe there is a electron as a particle please say so and we may move on but if you believe there is we need to concentrate on that question alone. You need to state your beliefs quite clearly.

See various previous comments from the past year or so.

Mmfiore:

First of all, apologies for not getting back to you on that other topic you started about the ether and all that. I started writing a reply but didn't finish it. I'll finish it later.

Here is a more universal definition for the word “understand”

OK. Fire away.

To perceive and comprehend the nature and significance of nature.

Mmm. No definition so far. "Comprehend" is a synonym for "understand". So you seem to be defining "understand" as "to understand the nature of nature".

Also, to grasp or comprehend the meaning and to have knowledge of something. Imagine that someday it may be possible to simply know and understand this reality deeply. That’s the goal. We need to unite toward the same goal and we are not there.

Sorry but this seems like more meaningless hand-waving to me. I'm all in favour of awe at the mysterious grandeur of the universe. Not a single day goes by when I don't think about various aspects of the universe and the strange fact that bits of that universe have grown into creatures that can contemplate their own origins. But for that reason I am all the more uninterested in mystical misuse of language. I prefer language to say something that corresponds to something that I can sense.

Wake up! You can do it. There is a brave new world out there, a world where everything makes sense.

Sounds a bit like "have you heard the good news?". Sounds like you think you've found the ultimate answer without really knowing what the question is.

Mmfiore's stated definition of the word "understand":

To perceive and comprehend the nature and significance of nature.

Hmm, interesting reply since the definition I supplied is taken directly from webster.

I've had a look. No it isn't. It's all your own work.

LOL Ah, the oh so typical response from a QM advocate. Criticize the person who attempts to define something and then supply no answer themselves.

Your defintion was stated by yourself as a reply to my own definition of the word "understand"!?!? You are making absolutely no sense. And stop calling me a QM advocate and insulting half of my brain. You've never even seen my brain. And all I am advocating is talking about things that can be sensed. i.e. not talking non-sense.

Fanman:

Thank you! I've disagreed with you vehemently on some other issues about religion and stuff. I take it all back! I also apologize for ridiculing you a bit in the past when you claimed that there was no gravity in space. (I'm easily won over by a bit of praise.)

Xris:

OK, here's my take on "electron" (at 10pm after having to drive home from Harlow in Essex (have you been there? It's a dump) and drinking two beers):

Its physical properties - electric charge, intrinsic spin etc are well documented. It appears to behave in some ways that could be described by the set of mathematics that is collectively known as "particle" and in other ways by the other set of mathematics that could be described as "wave". And in other ways by other bits of mathematics.

You asked what shape it has. I like the question, but could you describe what you mean by the word "shape"? The most common definition of the word I'm familiar with relates to large composite objects. My computer screen is rectangular because of the location of squillions of atoms around its periphery. To ask for the shape of an electron seems a little like asking for the temperature of a single gas molecule at a single instant of time. Shape, like temperature, seems to me a macroscopic concept that is meaningless at this scale.

Having said that, I guess maybe you could describe the shape of its electric field as spherical, as it is spherically symmetrical. But that's a different sense of the word "shape" than the one that is used in everyday speech.

McDoodle:

You can't see an electron but you can follow its tracks and trace where its tracks have been, make predictions about where it might be, isolate it, and use it in all sorts of amazing ways.

I liked your little synopsis of the history of the electron, which ended with this quote. The quote is interesting in that you say that we can't see electrons. Since it is the outer electrons of the outer atoms of objects that reflect the light, you could argue that electrons are all that we see. But I think it illustrates why some people get confused when trying to apply everyday language to concepts like this. People sometimes say things like: "nobody has ever seen an electron!" as evidence that the concept is meaningless. But, for that statement, or any other, to have meaning we have to define what we mean by "see". If we mean it in the everyday sense, then we can never see anything that doesn't reflect or emit light.

McDoodle:

Interesting comments about the possible shape of the electron. As I say, I think considering questions like this is interesting because it forces us to think carefully about exactly what we mean by words. In ordinary usage, the word "shape" is associated with the spatial location of the parts of an object that constitute its outer periphery or surface. In practice, this means the locations of the outer atoms of the object. This requires (1) that the object is composed of many atoms and (2) we make a decision as to what constitutes the positions of those atoms. Is it the centre of each atom? Is it an arbitrarily chosen point in space "outside" the atom where the electrostatic repulsion of its outer electrons falls to a level chosen by us?

Do you think this usage is applicable when talking about something like an electron? Clearly not, in the way I've described it. Electrons are not composed of atoms! But perhaps they could have shape if they do have some other kind of internal structure. Current theories of physics, however, (as I understand them) say that electrons do not have internal structure. (They are leptons - elementary particles.) But they do have properties, like intrinsic spin, that are analogous to properties of other objects that do arise as a result of internal structure. Intrinsic angular momentum, or spin, in the "classical" sense of the word, only makes sense when talking about objects with individual parts than can rotate around an axis which goes through the centre of mass of the object. Spin, as applied to things like electrons, is not the same thing. But it has the same name because it shares some mathematically described properties of classical spin. But not all properties. Use of words like this constantly confuses people because this sense in which it is merely an analogy is perhaps not made clear enough.

I think a lot of the confusion about physics stems from the fact that when using apparently simple obvious words like "shape", if we are going to say anything meaningful, we have to be very careful about precisely what we are saying. Often words like this are used in deeply metaphorical ways which are only faintly related to the everyday use of the word.

Mcdoodle:

I certainly don't think it [the electron] is spherical, though it probably has some sort of surface.

How would you define the word "surface" in this context?

McDoodle: Thanks for the clarification. My question about your use of the word surface wasn't meant as a "how dare you use the word surface!" I just thought it was an interesting way of talking about the use of language, as we've discussed.