Freethought & Rationalism Archive

Blueskyboris · 10-29-2004, 01:48 PM

Jesse:

Listen bubbles, assuming that I am using the word "interpretation" in relation to QM to mean "hunch" is exactly that that and more. QM physcists mean by interpretation, "a detailed proposal about how we can interpret the mathematical formalism of quantum mechanics in terms of some physical model", is exactly the same as "to give or provide meaning of X." X in QM is the phenomena, the positions and velocity of electrons, that has not yet been understood either mathematically or empirically. This phenomena is open to interpreatation. The "provide meaning" in QMs interpretation are the theories put forth to attempt to explain why the phenomena acts in such and such a way. These theories can be based on mathematical demostrations, deductive reasoning, empirical based theorizing. In short, an interpretation is a theoretical proposal presented for scrutiny by those who have experience in the field. This same exact process happens in all the sciences. It is the very bedrock of scientific inquiry and is not limited to QM.

Jesse · 10-29-2004, 02:26 PM

Quote:

Originally Posted by Blueskyboris

Listen bubbles,

No pet names please, "Jesse" will do fine.

Quote:

Originally Posted by Blueskyboris

assuming that I am using the word "interpretation" in relation to QM to mean "hunch" is exactly that that and more. QM physcists mean by interpretation, "a detailed proposal about how we can interpret the mathematical formalism of quantum mechanics in terms of some physical model", is exactly the same as "to give or provide meaning of X." X in QM is the phenomena, the positions and velocity of electrons, that has not yet been understood either mathematically or empirically.

Nope, every aspect of the mathematical formalism of QM needs to be addressed in detail by an "interpretation" as physicists use the term, not just the uncertainty principle. And just saying "I believe all particles have a definite position and momentum at all times" is not sufficient to address the uncertainty principle itself. If you are proposing a hidden-variables interpretation, then your physical model must explain how measurements influence particles to produce the observed uncertainty relation--for example, Bohmian mechanics says the movements of a particle are guided by a "pilot wave", so presumably his interpretation should be able to tell us how any given type of physical measurement affects the pilot wave, and how this in turn affects the position and momentum of the particle to produce the observed uncertainty relations in that specific situation. Is your idea specific enough that you can apply it to specific situations? For example, the double-slit experiment can be understood in terms of the uncertainty principle, as I discussed in a post on another thread:

Quote:

Perhaps you should read up on the Feynman double-slit experiment, one of the most fundamental quantum experiments discussed in most popular QM books:

http://www.upscale.utoronto.ca/Gener...oubleSlit.html

In this experiment, if you don't measure which slit an electron went through, and you add up the number of electron hitting different parts of the screen, then their distribution will look like an interference pattern of the same type you'd get with water waves, as illustrated by the blue line in this diagram:

On the other hand, if you place detectors at the slits so you know which slit each electron went through, then if you look only at electrons going through the left slit, they will form a simple "hump" distribution similar to what you'd get if you shot classical particles like bullets through a hole, and you'll see the same type of distribution if you look only at the electrons which went through the right slit, so the total distribution of all the electrons on the screen is simply the sum of the two humps:

As discussed on this page (in the section 'Watching Electrons in the Double-Slit Experiment), the fact that we only see an interference pattern on the screen if we don't know which slit the electron went through can be understood as a consequence of the uncertainty principle. Shining light on an electron can tell you something about its position, and the smaller the wavelength of the light used, the greater the resolution of the image, so the less uncertainty in the electron's position. But it turns out that the interference pattern is destroyed if the uncertainty in each electron's momentum is too large, and since less position uncertainty = larger momentum uncertainty, this means there's a minimum wavelength of light you can shine on the electrons and still get an interference pattern. When you actually calculate this minimum wavelength, it turns out to be exactly equal to the distance between the slits...but to actually know which of the two slits it went through, you'd need a wavelength smaller than the distance between the two slits!

So the uncertainty principle guarantees that you only get an interference pattern if you don't know which slit it went through--if you do know, then you will get the sum of two hump-patterns. According to your interpetation, then, it is presumably the interaction with the photons that causes the electrons to behave differently, so that the distribution of positions where the electrons hit the screen looks like a sum-of-humps rather than an interference pattern. But there is another way to tell which slit an electron went through without bouncing any photons off it--just block off one of the slits, insuring that any electron that does make it to the screen must have gone through the other slit! In this case, if you block off each slit and look at the distribution of electrons on the screen, you will also get two humps, just like if you used photons to measure which slit each electron went through:

So clearly it is not just the electron's interactions with the photons that cause them to behave differently in this experiment--the uncertainty principle is more fundamental, because any way of obtaining knowledge of which slit each electron went through (even ways involving no interaction between the electron and other particles, like blocking off the other slit) will yield the same result, namely the electrons making a hump-shaped distribution on the screen rather than an interference pattern.

So do you have any idea about why the electrons show an interference pattern when both slits are open but no detectors are present, but why either placing detectors at the slits or closing off one of the slits will cause all the electrons going through an open slit to make a single-hump pattern on the screen? If not, you don't have a genuine hidden-variables interpretation of QM, since you can't explain what's going on with these hidden variables in every specific situation covered by the mathematical formalism of QM.

Blueskyboris · 10-29-2004, 05:19 PM

Jesse:

Nope, every aspect of the mathematical formalism of QM needs to be addressed in detail by an "interpretation" as physicists use the term, not just the uncertainty principle.

This is a major flaw with modern physics and the modern severing of "philosophy" from "science": You are so cut off from conceptual philosophy you dont even know what a concept means.

Can you explain, by example, how physicists use the concept "interpretation" different than the rest of science?

And just saying "I believe all particles have a definite position and momentum at all times" is not sufficient to address the uncertainty principle itself.

No shit, Sherlock. That is why philosophy has "theoretical physicists" to hypothesize, based on their knowledge of the subject, as to why such and such a phenomena might occur, and "physicist fact-finders" to prove or disprove the theories. Sometimes we are graced and these jobs are accomplished by one individual.

If you are proposing a hidden-variables interpretation, then your physical model must explain how measurements influence particles to produce the observed uncertainty relation

All I am doing is pointing out that a hidden-variables interpretation is still a valid interpretation. I am only interested in the fact that physics has not proved the issue either way. (This misunderstanding as to the reason for my interest in QM is why I dont approve of severing part of a thread when the debate expands beyond the immediate subject matter. It creates a logical disconnection such as this. I hope a moderator is reading.)

Blueskyboris · 10-29-2004, 06:11 PM

Hey,

I do not assume randomness, I conclude it is the best explanation.
You offer no counterargument. I also realize that statistical
behavior gives well defined expectation values.

Excellent. Please read my arguments about the essence of statistics in Evolutionary Theory Critiqued in the Evolution/Creation section. I will post tomorrow (at some point).

I tried to, but you wouldn't discuss what the meaning of delta x was.
If delta x is an *inherent* distribution about an average, then
such a thing IS randomness by any definition.

Yes, yes, I understand you are using statistical theorems to gain an understanding of processes that physics has a limited understanding about.

Now if they are deep down unknowable, then there is a reason for our
limitation on knowing things - it is a QM property that only so much can
be known about physical systems.

This is why I was interested in the Uncertainty Principle. It seems to say that we are limited, fundamentally, in what we can know about the processes of atomic physics, and deeper. That said, we can use known tools to gain knowledge about these processes, because we have limited knowledge (a sample so to speak) about them. This is why Sam, the main character in the sci-fi television show Quantum Leap, leaps "randomly" from timeframe to timeframe. We only know where the electron will be in probability, because we are barred from knowing it predictably, for what ever reason, at this point in our understanding of the natural world. Our knowledge of subatomic physics is incomplete and hence only through statistical theorems do we get a imperfect picture of what is going on.

[Do you understand the words that are coming out of my mouth?]

No. But since no words came out of your mouth I am not surprised I do not understand.

Jesse · 10-29-2004, 07:30 PM

Quote:

Originally Posted by Blueskyboris

Jesse:

Nope, every aspect of the mathematical formalism of QM needs to be addressed in detail by an "interpretation" as physicists use the term, not just the uncertainty principle.

This is a major flaw with modern physics and the modern severing of "philosophy" from "science": You are so cut off from conceptual philosophy you dont even know what a concept means.

Another strange non sequitur--my understanding of "concepts" has never come up in our discussion. We were only discussing the technical definition of the term "interpretation of quantum mechanics".

Quote:

Originally Posted by Blueskyboris

Can you explain, by example, how physicists use the concept "interpretation" different than the rest of science?

I already gave a link which has a pretty good discussion of the technical meaning of "interpretation" in quantum mechanics:

http://mist.npl.washington.edu/npl/i...iqm/TI_20.html (see section 2.0.1)

But to give my own summary, I'd say that an "interpretation" must firstly provide a mapping between the various mathematical elements of the formal theory and elements of physical reality which we can actually observe experimentally--for example, in the Copenhagen Interpretation the eigenstates of a system correspond to different possible measurements of a particular physical variable (say, position), and the absolute value of the square of the amplitude of the wavefunction on these different eigenstates is understood to mean the probability that the system will actually have that value of the variable when it is measured.

An interpretation may also postulate additional elements of physical reality which don't play a role in the mathematical formalism and which are not directly observed, such as the offer wave/confirmation wave in the Transactional Interpretation, or the hidden variables and the pilot wave in Bohm's Causal Interpretation, or the other "worlds" in the Many-Worlds Interpretation. Any interpretation which postulates such additional unobserved elements of physical reality must give general rules for how these entities relate to the observed entities, and how they behave in any possible situation which can be described by the mathematical formalism. If you can't do this--for example, if you postulate hidden variables but have no idea how they are behaving in the double-slit experiment--then you don't have an "interpretation" as physicists would use the term.

Quote:

Originally Posted by Blueskyboris

And just saying "I believe all particles have a definite position and momentum at all times" is not sufficient to address the uncertainty principle itself.

No shit, Sherlock. That is why philosophy has "theoretical physicists" to hypothesize, based on their knowledge of the subject, as to why such and such a phenomena might occur, and "physicist fact-finders" to prove or disprove the theories. Sometimes we are graced and these jobs are accomplished by one individual.

Then do you agree that your own ideas are not sufficiently well-defined to qualify as an "interpretation of QM" in the technical sense, since you yourself haven't done the work of figuring out how to explain the uncertainty principle in terms of these hidden variables?

Quote:

Originally Posted by Blueskyboris

If you are proposing a hidden-variables interpretation, then your physical model must explain how measurements influence particles to produce the observed uncertainty relation

All I am doing is pointing out that a hidden-variables interpretation is still a valid interpretation.

Yes, but saying "I believe in hidden variables" is not itself a "hidden-variables interpretation". Bohmian mechanics is a hidden-variables interpretation, and perhaps the Transactional Interpretation is too, although I'm not sure about that. Both of these are sufficiently detailed that they could be applied to any specific physical experiment, such as the double-slit experiment. But you have not offered anything that qualifies as a hidden-variables interpretation yourself--if you are just saying that there already exist valid hidden-variables interpretations originated by others, such as Bohmian mechanics, I agree with you (although as was pointed out earlier, it's not clear whether Bohmian mechanics can be generalized to cover quantum field theory).

Quote:

Originally Posted by Blueskyboris

I am only interested in the fact that physics has not proved the issue either way.

Has anyone on this thread disagreed with you on that point? I certainly haven't.

Answerer · 10-30-2004, 08:47 AM

Quote:

Originally Posted by Blueskyboris

Guys, I would advise you not to heed these unwise words. Each individual posting arguments on these boards has a rational faculty called "the mind." Therefore, if what I am saying is in fact gibberish, you will pick up on it quite easily. Please confront what is at issue directly, the Uncertainty Principle.

:down:

Yeah, say whatever you like but I can tell you one thing for sure that no one is going to give a damn to what your beliefs are and what you say unless you first learn to be polite plus providing some evidences and convincing arguments.

Furthermore, it is super obvious that your purpose here is not to prove us wrong, seek alternative views or even to learn about something. You are here because you have nothing better to do .

And before you decide to give me the same shit again, please have the basic human courtesy of letting me finish first. You are certainly not the first arrogant and disrespectful person we had seen and neither will you be the last. And I'm more than willing to put my money that you, just like so many others before you, will not be in our forums for long.

Blueskyboris · 10-30-2004, 12:57 PM

Jesse:

"Interpretation" is a concept Jesse. You are claiming that the concept itself is different in Quantum Phyics. I am arguing it isnt.

I will concede that the content of Quantum Physics is different than the content of say Biochemistry, but I am not going to concede that the concept Interpretation is used different.

To give or provide meaning to X is the concept of "interpretation" in all areas of inquiry. Only the content (X) is different. X in biochemistry is the body of mysteries in biochemistry, while X in Quantum Physics is the body of mysteries in Quantum Physics.

I'd say that an "interpretation" must firstly provide a mapping between the various mathematical elements of the formal theory and elements of physical reality which we can actually observe experimentally

This is true, but only in a narrow Quantum-Physicist-to-Quantum-Physicist way. All I am concerned with is whether you guys have come to the conclusion that you have "proved" that the universe is random in its essence or not. I am not a Quantum Physicist.

Yeah, say whatever you like but I can tell you one thing for sure that no one is going to give a damn to what your beliefs are and what you say unless you first learn to be polite plus providing some evidences and convincing arguments.

Answerer:

Dude, you have been rude to me from the get-go in this thread. In this specific thread I have been demanding that posters confront directly what I am interested in: the Uncertainty Principle. They have not. So if I get a little pissy in the process of "beating around the bush" I am sure readers are not going to fault me.

Furthermore, it is super obvious that your purpose here is not to prove us wrong, seek alternative views or even to learn about something. You are here because you have nothing better to do .

So who indeed started the ad hominem attack first, sir? You did. Proof of your sophisticaed ad hominem attack is as follows:

Guys, I will advise you all to reduce the amount of time on blue as he hadn't provided any single convincing evidences or arguments to support his beliefs while kept on accusing and demanding answers from others who tend to disagree with him. Furthermore, so far his statements here (and in another thread at e & c) like to go something like that:

I don't like that theory, therefore it must be wrong or correct for now

If I were you, I would ask myself some deep questions after reading my reply.

Bluesky.

Tetlepanquetzatzin · 10-30-2004, 01:06 PM

Quote:

Originally Posted by Blueskyboris

Are you ever going to explain how the Uncertainty Principle proves randomness as a fundamental characteristic of the universe, or are your going to continue to travel the character-assination path?

Neither.

Quote:

Originally Posted by Blueskyboris

I would argue that because you refuse to answer my question, you have no idea what you are talking about.

Is that an invitation to travel the path of character-assassination?

Your conclusion does not follow. For one thing, it is not my goal to answer your question. Rather, my goal is to comment on certain statements made by you in this thread. My most important point concerns the status of interpretations of QM. One could phrase the issue as Jesse does and say that the word "interpretation" has a stricter meaning in this context. Or one could phrase it more bluntly by noting the difference between interpretations that are informed and thoughtful and interpretations that are not. Libraries are by now full of informed and thoughtful discussions (as well as crappy discussions) and therefore the bar has been set quite high for what we regard as a (noteworthy) interpretation. For this reason it is a mistake to try to imply that interpretations of QM are somehow arbitrary or capable of being summarily dismissed simply because they are "just interpretations". A better argument would be to note the diversity of opinion among those informed authors who have thought hard about the problem.

Tetlepanquetzatzin · 10-30-2004, 01:26 PM

Quote:

Originally Posted by Blueskyboris

In this specific thread I have been demanding that posters confront directly what I am interested in: the Uncertainty Principle. They have not.

Let me remind you that my very first comments to you were:

"What do you make of the fact that there are no simultaneous eigenstates of both position and momentum? Or the x- and z-components of angular momentum?"

These questions directly concern the reason for quantum mechanical uncertainty principles (which, loosely speaking, are quantitative measures of how different e.g. momentum eigenstates are from position eigenstates). You avoided these questions.

LambdaCalculator · 10-30-2004, 01:45 PM

Quote:

Originally Posted by Blueskyboris

To give or provide meaning to X is the concept of "interpretation" in all areas of inquiry. Only the content (X) is different. X in biochemistry is the body of mysteries in biochemistry, while X in Quantum Physics is the body of mysteries in Quantum Physics.

If this is philosophy, it's extremely sophomoric philosophy.

Your primary error is linguistic in nature, because you falsely assume that words apply to all concepts simultaneously. They don't. While "theory" can mean "speculation" in every day language, it means something totally different in science. According to the National Academy of Sciences (NAS), a scientific theory is "a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses."

Likewise, interpretation can have a different meaning in quantum physics than it does in every day language. And it's been explained to you, over and over, why this is true. Your arguments boil down to "I believe it, that settles it". You have not privided any way of your own of understanding the predictions of QM, and until you do we're only running around in circles in this thread.

Cheers,

-- Black Cap

10-29-2004, 06:11 PM	#34
Blueskyboris Banned Join Date: Oct 2004 Location: Inside a Cheeseburger Posts: 5,374	Tracy Hey, I do not assume randomness, I conclude it is the best explanation. You offer no counterargument. I also realize that statistical behavior gives well defined expectation values. Excellent. Please read my arguments about the essence of statistics in Evolutionary Theory Critiqued in the Evolution/Creation section. I will post tomorrow (at some point). I tried to, but you wouldn't discuss what the meaning of delta x was. If delta x is an inherent distribution about an average, then such a thing IS randomness by any definition. Yes, yes, I understand you are using statistical theorems to gain an understanding of processes that physics has a limited understanding about. Now if they are deep down unknowable, then there is a reason for our limitation on knowing things - it is a QM property that only so much can be known about physical systems. This is why I was interested in the Uncertainty Principle. It seems to say that we are limited, fundamentally, in what we can know about the processes of atomic physics, and deeper. That said, we can use known tools to gain knowledge about these processes, because we have limited knowledge (a sample so to speak) about them. This is why Sam, the main character in the sci-fi television show Quantum Leap, leaps "randomly" from timeframe to timeframe. We only know where the electron will be in probability, because we are barred from knowing it predictably, for what ever reason, at this point in our understanding of the natural world. Our knowledge of subatomic physics is incomplete and hence only through statistical theorems do we get a imperfect picture of what is going on. [Do you understand the words that are coming out of my mouth?] No. But since no words came out of your mouth I am not surprised I do not understand.

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10-29-2004, 01:48 PM	#31
Blueskyboris Banned Join Date: Oct 2004 Location: Inside a Cheeseburger Posts: 5,374	Jesse: Listen bubbles, assuming that I am using the word "interpretation" in relation to QM to mean "hunch" is exactly that that and more. QM physcists mean by interpretation, "a detailed proposal about how we can interpret the mathematical formalism of quantum mechanics in terms of some physical model", is exactly the same as "to give or provide meaning of X." X in QM is the phenomena, the positions and velocity of electrons, that has not yet been understood either mathematically or empirically. This phenomena is open to interpreatation. The "provide meaning" in QMs interpretation are the theories put forth to attempt to explain why the phenomena acts in such and such a way. These theories can be based on mathematical demostrations, deductive reasoning, empirical based theorizing. In short, an interpretation is a theoretical proposal presented for scrutiny by those who have experience in the field. This same exact process happens in all the sciences. It is the very bedrock of scientific inquiry and is not limited to QM.

10-29-2004, 05:19 PM	#33
Blueskyboris Banned Join Date: Oct 2004 Location: Inside a Cheeseburger Posts: 5,374	Jesse: Nope, every aspect of the mathematical formalism of QM needs to be addressed in detail by an "interpretation" as physicists use the term, not just the uncertainty principle. This is a major flaw with modern physics and the modern severing of "philosophy" from "science": You are so cut off from conceptual philosophy you dont even know what a concept means. Can you explain, by example, how physicists use the concept "interpretation" different than the rest of science? And just saying "I believe all particles have a definite position and momentum at all times" is not sufficient to address the uncertainty principle itself. No shit, Sherlock. That is why philosophy has "theoretical physicists" to hypothesize, based on their knowledge of the subject, as to why such and such a phenomena might occur, and "physicist fact-finders" to prove or disprove the theories. Sometimes we are graced and these jobs are accomplished by one individual. If you are proposing a hidden-variables interpretation, then your physical model must explain how measurements influence particles to produce the observed uncertainty relation All I am doing is pointing out that a hidden-variables interpretation is still a valid interpretation. I am only interested in the fact that physics has not proved the issue either way. (This misunderstanding as to the reason for my interest in QM is why I dont approve of severing part of a thread when the debate expands beyond the immediate subject matter. It creates a logical disconnection such as this. I hope a moderator is reading.)

10-30-2004, 12:57 PM	#37
Blueskyboris Banned Join Date: Oct 2004 Location: Inside a Cheeseburger Posts: 5,374	Jesse: "Interpretation" is a concept Jesse. You are claiming that the concept itself is different in Quantum Phyics. I am arguing it isnt. I will concede that the content of Quantum Physics is different than the content of say Biochemistry, but I am not going to concede that the concept Interpretation is used different. To give or provide meaning to X is the concept of "interpretation" in all areas of inquiry. Only the content (X) is different. X in biochemistry is the body of mysteries in biochemistry, while X in Quantum Physics is the body of mysteries in Quantum Physics. I'd say that an "interpretation" must firstly provide a mapping between the various mathematical elements of the formal theory and elements of physical reality which we can actually observe experimentally This is true, but only in a narrow Quantum-Physicist-to-Quantum-Physicist way. All I am concerned with is whether you guys have come to the conclusion that you have "proved" that the universe is random in its essence or not. I am not a Quantum Physicist. Yeah, say whatever you like but I can tell you one thing for sure that no one is going to give a damn to what your beliefs are and what you say unless you first learn to be polite plus providing some evidences and convincing arguments. Answerer: Dude, you have been rude to me from the get-go in this thread. In this specific thread I have been demanding that posters confront directly what I am interested in: the Uncertainty Principle. They have not. So if I get a little pissy in the process of "beating around the bush" I am sure readers are not going to fault me. Furthermore, it is super obvious that your purpose here is not to prove us wrong, seek alternative views or even to learn about something. You are here because you have nothing better to do . So who indeed started the ad hominem attack first, sir? You did. Proof of your sophisticaed ad hominem attack is as follows: Guys, I will advise you all to reduce the amount of time on blue as he hadn't provided any single convincing evidences or arguments to support his beliefs while kept on accusing and demanding answers from others who tend to disagree with him. Furthermore, so far his statements here (and in another thread at e & c) like to go something like that: I don't like that theory, therefore it must be wrong or correct for now If I were you, I would ask myself some deep questions after reading my reply. Bluesky.

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