How does physics allow for the existence of observers?

[Loren Booda]

How does physics allow for the existence of observers?

 

[yesicanread]

How does physics allow for the existence of observers?

Point symmetry, and observing the perimeter. I think off hand.

 

[loseyourname]

What the heck are you asking? Observers exist. Physics doesn't allow or disallow this. It only describes the interactions that take place.

 

[balkan]

how does physics allow for interaction between particles you ask? that's a pretty broad question...

 

[wuliheron]

How does physics allow for the existence of observers?

Relativistically of course.

 

[Rader]

How does physics allow for the existence of observers?

Loren are you a psychologist? I always get the feeling by your questions, your are studying, not so much the answer but who answers and how.

Through photon exchange.

 

[Loren Booda]

loseyourname, you may well have said that observers do not interact with their physical environment. I suppose you would disagree with the Anthropic principle. Are observers then metaphysical entities?

balkan, for instance, one might state that physics requires the presence of observers. Does physics itself explain what observers are, though?

wuliheron, could also observer and object exist as quantum mechanical complements?

Rader, I often couch my statements in the form of questions. Perhaps that seems psychoanalytical. I do have some background in psychology, though. I tend to ask and stand back, in part because I do not respond as quickly as others (especially in philosophy).

 

[loseyourname]

loseyourname, you may well have said that observers do not interact with their physical environment. I suppose you would disagree with the Anthropic principle. Are observers then metaphysical entities?

You're losing me, Loren. I just said that physics explains the interaction between observer and environment and you think I may well have said that observers do not interact with their environment? How'd you make that leap?

 

[balkan]

balkan, for instance, one might state that physics requires the presence of observers. Does physics itself explain what observers are, though?

one might state that, yes. One might state that the queen of britain is made of french cheese, but that doesn't give it any relevance or validity...
what have you got going for it?

 

[Loren Booda]

Please excuse my froginess, lyn. Your present translation I agree with for the most part. You may wish to review your exact original wording that I responded to:

What the heck are you asking? Observers exist. Physics doesn't allow or disallow this. It only describes the interactions that take place.

How might describing an interaction necessarily allow for a separate observer and object? Also, do you believe that the Anthropic principle could give a physical justification for the presence of observers?

balkan, I inferred from you, as from loseyourname, that interaction is essential to the identity of observers, and may be the link to their physicality. If observers are not themselves physical, how can one explain apparent direct interactions between them?

 

[balkan]

balkan, I inferred from you, as from loseyourname, that interaction is essential to the identity of observers, and may be the link to their physicality. If observers are not themselves physical, how can one explain apparent direct interactions between them?

why wouldn't observers be physical? and why on Earth should the universe neccessarily have observers in order to exist... nobody would know it existed, but what has that got to do with anything?
that's like saying bacteria didn't exist until we discovered them...

 

[Loren Booda]

...or as Einstein mused to the quantum mechanics, that the Moon didn't exist unless we were looking at it.

If not unphysical, observers may well follow different physical laws relative to each other than to their objects.

 

[haroldjrbw]

You make a good point Loren about Einstein and quantum mechanics. Either quantum mechanics points to the metaphysical or we live with Alice in Wonderland. We either live in an observer based reality where nothing exists until observed or we live in many-worlds and everytime a decision is made a split occurs.

With many-worlds you have to allow for quantum immortality for instance:

Say I'm out shopping and I either decide to stop shopping and cross the street to my car or I continue shopping and walk into the next shop. In one world I cross the street to my car and I get hit by a truck and die yet I'm still alive and shopping in the other world. Quantum immortality doesn't violate quantum physics.

Obviously some have trouble with an obsever in physics because of the metaphysical implications. One, they can't really define an observer and two they don't know why the observer causes the wave function to collapse. This is why some try to minimize the role of the observer or eliminate it with no-collapse theories, especially in quantum cosmology.

Like I said in an earlier post I think many-histories fits better than many-worlds, along with the role of the observer.

THANK YOU, LORD JESUS!

 

[wuliheron]

wuliheron, could also observer and object exist as quantum mechanical complements?

Yes, but even then they would be relative. Am I the observer, or the observed? It really just depends upon the context. Since no one has ever proven the existence of any kind of logic behind quantum mechanics, the only demonstrably meaningful answer we can give is a relativistic one.

 

[balkan]

harold, i think you have quite confused yourself with those quantum mechanics statements...
the electron does not have to be observed in order to do anything, but you cannot be sure of it's location until you check it out due to uncertainty... it surely does exist before being observed, but you just cannot be sure about where it is, so the "nothing exist until observed" is quite false...

the many worlds idea is just a theory, but it is definitely not a neccessity. there are plenty of other theories to go around.

and please stop that "THANK YOU LORD JESUS" thing. i don't go around posting "GOD DOESN'T EXIST!" or "GOD EXIST ONLY FOR YOUR PSYCHOLOGICAL COMFORT!" do i?
please show the same courtesy.

 

[Rader]

harold, i think you have quite confused yourself with those quantum mechanics statements...
the electron does not have to be observed in order to do anything, but you cannot be sure of it's location until you check it out due to uncertainty... it surely does exist before being observed, but you just cannot be sure about where it is, so the "nothing exist until observed" is quite false...

the many worlds idea is just a theory, but it is definitely not a neccessity. there are plenty of other theories to go around.

and please stop that "THANK YOU LORD JESUS" thing. i don't go around posting "GOD DOESN'T EXIST!" or "GOD EXIST ONLY FOR YOUR PSYCHOLOGICAL COMFORT!" do i?
please show the same courtesy.

Please do not worry we know you are not Harold. :surprise:

 

[balkan]

i know... i have more backbone than that...




GOD EXIST ONLY FOR YOUR PSYCHOLOGICAL COMFORT!

 

[balkan]

hehe...

 

[Fliption]

harold, i think you have quite confused yourself with those quantum mechanics statements...
the electron does not have to be observed in order to do anything, but you cannot be sure of it's location until you check it out due to uncertainty... it surely does exist before being observed, but you just cannot be sure about where it is, so the "nothing exist until observed" is quite false...

This doesn't agree with anything I have ever read on quantum physics. This seems to imply that the problem we face with quantum physics is purely a problem of what we can know (epistomology) and not a statement about reality itself. Here's a simple quote from a website that while it doesn't say "nothing exists", it clearly states that the ontology of subatomic particles changes as a result of an observation. Some people have written that it isn't really inaccurate to say that subatomic particles don't really exist anywhere or anywhen until observed.


"An unobserved quantum entity is said to exist in a "coherent superposition" of all the possible "states" permitted by its "wave function." But as soon as an observer makes a measurement capable of distinguishing between these states the wave function "collapses", and the entity is forced into a single state."

http://www.fortunecity.com/emachines/e11/86/qphil.html

 

[selfAdjoint]

There is an interpretaion of quantum mechanics (caricatured as "Shut up and calculate") that claims QM simply doesn't tell us what the particle is, or does, by itself. What QM enables us to do is to calculate the results of our experiments on the particle, and to do that we have to build information about the experiment into the calculating math. This is the "preparation" that Bohr laid so much stress on.

So in this interpretation the coherent superposition you mention is a mathematical stand-in that is needed for our calculation, but should not be confused with a statement about the nature of the particle. So for believers in this, QM is an epistomological theory, as you said.

But I emphasize this is only one interpetation. Many physicists are eager to reify the coherent superposition. These are the ones who make ontological assertions about the state of the particle and its properties between experiments.

 

[Fliption]

So in this interpretation the coherent superposition you mention is a mathematical stand-in that is needed for our calculation, but should not be confused with a statement about the nature of the particle. So for believers in this, QM is an epistomological theory, as you said.

I'm not familiar with this view so I will guess that it is a minority view at the current time. It's a shame because so many people will flock to this point without a full understanding of the issues because it allows them to hold on to the classical physics ontology that their brains can grasp. The post I was replying to seems to fall into this category. I thought we had moved beyond the billiard ball physics in the subatomic world but then I should probably do some study myself to fully understand this view.

 

[balkan]

I'm not familiar with this view so I will guess that it is a minority view at the current time. It's a shame because so many people will flock to this point without a full understanding of the issues because it allows them to hold on to the classical physics ontology that their brains can grasp. The post I was replying to seems to fall into this category. I thought we had moved beyond the billiard ball physics in the subatomic world but then I should probably do some study myself to fully understand this view.

it isn't "really inaccurate" like you said (because it simply doesn't make any sense to talk about an electrons position until observed)... but in quantum physics class and real quantum physics books, the theory is quite epistemological, if you want to use that word, yes.
lots of people wants to add something extra to it, but the entire point really boils down to the fact, that the electron has to be considered as being in an unknown position, that will only reveal itself when someone observes the electron... the fact that an observation necessarily involves manipulating the electron is what causes the need for other calculations...
the reason why it is formulated and calculated the way it is, is that it really makes no sense in any way to talk about a position, cause it could never be calculated (this is what einstein was so upset about)... only the probability density of its whereabouts can be calculated...

don't go back to the billiard ball model... the electron has a probability of being on the other side of the universe, it is just so very tiny, that it is neglected...

 

[Loren Booda]

Taking into account the past several posts, is an observer describable in classical or quantum mechanical terms?

 

[Fliption]

it isn't "really inaccurate" like you said (because it simply doesn't make any sense to talk about an electrons position until observed)... but in quantum physics class and real quantum physics books, the theory is quite epistemological, if you want to use that word, yes.

This is because the theory actually ties together human epistomology with ontology and seems to suggest that one actually influences the other. It's not just about epistomology. The math of this theory is one thing but when it comes to the interpretation of this theories results, there is ALOT of confusion and disagreement. If this is nothing but a theory of epistomology there would be nothing special about it to talk about or distort.

lots of people wants to add something extra to it, but the entire point really boils down to the fact, that the electron has to be considered as being in an unknown position, that will only reveal itself when someone observes the electron... the fact that an observation necessarily involves manipulating the electron is what causes the need for other calculations...

This is just classical physics you're describing here. Your're suggesting the uncertainty is based on our inability to measure something without physically altering what we measure. Newton could have postulated this. But Quantum physics is so much more than this.

I'll suggest this article again. It seems to illustrate, by referencing actual experients, that epistomology (or the potential for knowledge) actually seems to impact the ontology of subatomic particles.

http://www.fortunecity.com/emachines/e11/86/qphil.html

 

[balkan]

This is just classical physics you're describing here. Your're suggesting the uncertainty is based on our inability to measure something without physically altering what we measure. Newton could have postulated this. But Quantum physics is so much more than this.

I'll suggest this article again. It seems to illustrate, by referencing actual experients, that epistomology (or the potential for knowledge) actually seems to impact the ontology of subatomic particles.

no it's not... you just want to read it that way in order to preserve the philosophical argument...
it's mega-highly different from classical physics... the position is incalculable and impossible to predict, that's miles away from classical physics... and that has got nothing to do with our measuring equipment... you were the one bringing the measuring equipment up, and i tried to explain what is meant by "collapsing" of the wave... probably not well enough though... note how your quote says "is said"...

the notion of having the electron being in an area of probabilty, but "collapsing" when being observed, is made in order to make the point clear, that it cannot be predicted in any way... i.e. to avoid confusion and make a clear difference from classical physics...
at least that's what our teachers say when we ask them...

and there's always something to discuss... people still discuss whether or not evolution exists...

 

[wuliheron]

Taking into account the past several posts, is an observer describable in classical or quantum mechanical terms?

Words only have demonstrable meaning according to their function in a given context. In a quantum mechanical sense, an observer can be both the observer and not at the same time. In other words, something entirely incomprehensible without a specific context. This is why I assert that the only way modern physics can actually describe an observer is relativistically.

 

[Fliption]

no it's not... you just want to read it that way in order to preserve the philosophical argument...
it's mega-highly different from classical physics... the position is incalculable and impossible to predict, that's miles away from classical physics... and that has got nothing to do with our measuring equipment... you were the one bringing the measuring equipment up, and i tried to explain what is meant by "collapsing" of the wave... probably not well enough though... note how your quote says "is said"...

My quote says "is said"? What are you referring to?

the notion of having the electron being in an area of probabilty, but "collapsing" when being observed, is made in order to make the point clear, that it cannot be predicted in any way... i.e. to avoid confusion and make a clear difference from classical physics...
at least that's what our teachers say when we ask them...

But you are making a distinction between classical and quantum physics from an epistemic view only. I'm claiming, as the article will suggest, that there is indeed an ontological difference. It has to do with a lot more than just "we say it isn't anywhere because we cannot know or predict where it is." That is just a statement of epistomology. There is an actual difference between where a subatomic particle actually IS as opposed to a ball on a pool table. It's not just a statement of what we can know about that particle.

and there's always something to discuss... people still discuss whether or not evolution exists...

I am talking about among scientists themselves. I'm not talking about Joe Sixpack. I'm sure scientists don't question evolution. There has been much confusion and disagreement among scientists about the interpretation of Qm results. This would not be the case if it were only a theory of epistomology.

 

[selfAdjoint]

Whatever your intepretation of QM, the particle is definitely not a classical object like a billiard ball. The math you have to use, however you interpret it, guarantees that. Even Bohm's version is not classical, since it has instantaneous changes over distances. Quantum mechanics, with its non-classicality, has passed a huge number od tests and is now the standard way to handle small energy things in the lab. Philosophers who persist in using classical conceptions are just painting themselves into a corner.

 

[haroldjrbw]

The big dillema for many is the nature of QM and what it says about our universe. This is what Einstein had a problem with and this is what led to the debates between him and Neils Bohr. We know that these things exist as a wave of probabilities until observed. This begs the question, why is there symmetry between conscious beings? In other words why does the universe appear to us in this particular state instead of another state? What caused the universe to choose this state out of all probable states?

Take John Wheeler's thought experiment and the delayed choice experiment. In short, an observer determines the state of the photon after it has already passed through the slits. This is mind-boggling, it's like we caused something to happen "after" it has already occured. It's like time is frozen until observation occurs. If anyone needs me to go into the double-slit experiment or the delayed choice experiment I will.

So the question is what or WHO caused the probability wave of the universe to collapse and appear to us in this fashion. I know some try to eliminate the role of the observer through no collapse theories like many worlds but Copenhagen, Bell's Theorum and delayed choice shows the observer affects which measurement occurs. I think this among other things points to a metaphysical origin.

THANK YOU, LORD JESUS!

 

[Fliption]

Whatever your intepretation of QM, the particle is definitely not a classical object like a billiard ball. The math you have to use, however you interpret it, guarantees that. Even Bohm's version is not classical, since it has instantaneous changes over distances. Quantum mechanics, with its non-classicality, has passed a huge number od tests and is now the standard way to handle small energy things in the lab. Philosophers who persist in using classical conceptions are just painting themselves into a corner.

The sad part about this is that it is the less philosophical and more scientific types that tend to make this mistake(in this forum). This is just what I've observed. I think they hesitate to accept the strangeness because of all the wild interpretations that people will naturally think up as a result. I can provide links to these threads if you'd like.

 

[vanesch]

So the question is what or WHO caused the probability wave of the universe to collapse and appear to us in this fashion. I know some try to eliminate the role of the observer through no collapse theories like many worlds but Copenhagen, Bell's Theorum and delayed choice shows the observer affects which measurement occurs. I think this among other things points to a metaphysical origin.

Let us try to put things in order.

Quantum theory describes the state of a system as something that is evolving unitarily and reversibly as a function of time. But that state is experimentally inaccessible. When we "decide to make a measurement" we have to stop that time evolution, and from the state at hand (as a mathematically calculated entity) we can calculate probabilities of what's going to be the result of the measurement. According to the observed outcome, the state now jumps into an eigenstate corresponding to that result, and then evolves from there on unitarily.
For all practical purposes, this algorithm of calculating probabilities of measurements WORKS. It is von Neuman who formalized it.

And now comes the crux of the Measurement Problem:
how come that the evolution of a state, "unobserved" is radically different from an "observation". Both are mathematically incompatible, because the "observation" operation is a probabilistically chosen projector, and the "evolution" operation is a unitary operator.
If we think of "observation" as a physical phenomenon as any other, we have a problem. This problem still stands out. Modern theories such as string theory or quantum gravity do not add much to it, because they fundamentally still work within that framework.

You could think that the question is open to scientific inquiry, because you could ask the question as "what is performing the measurement ?", in that it must somehow make a difference if I consider the apparatus that performs the measurement to be part of the system (and _I_ am the observer), or not, and the apparatus is performing the measurement. However, decoherence theory (an application of QM) indicates that from the moment that we need a macroscopic system (many degrees of freedom, coupled to a thermal bath) as a measurement apparatus, it will not make a difference in the outcome if we include it in the system or not!
So on one hand decoherence is a blessing, because it tells you that the theory of QM is self-consistent: you can choose at what point you decide that the measurement is made without changing the predictions ; on the other hand it makes experimental inquiry into the measurement problem very hard.

There are ways to tackle the problem, but all of them are vey strange. One is that, in the end, consciousness is what performs the measurement. Another is that nothing performs the measurement (many worlds); but in that case, our subjective experience *chooses* a worldline.
Finally, a more down-to-earth approach is to try to slightly modify quantum theory, such that state evolution is not quite unitary, and can give rise to collapse (by introducing nonlinearities). But this approach has the difficulty that whatever you twiddle in QM, you seem to change the very accurate predictions which have been verified up to now.

cheers,
Patrick.

 

[selfAdjoint]

Copenhagen View

Good post, Patrick!

I have been reading on the home page of http://www.mth.kcl.ac.uk/~streater/ - he of Streater and Wightman. He seems to adopt what I would call a modern Copenhagen view. He refuses to quantize the measuring apparatus and treats it as a classical system subject to classical probability. Then he can develop rigorous ways to combine that probability with the probability of the quantum system being measured. And this gives him a consistent picture. I suppose he could justify that based on the fast diagonalization of decoherence, spilitting the problem into a fullly decohered part of the environment, the apparatus, and a coherent part, the quantum system.