What is the opposite of realism in quantum mechanics?

[mjpam]

What is the opposite of "realism" in quantum mechanics?

I have been spending an awful lot of time reading about the philosophy of science where the opposite of "realism", insofar as "realism" constitutes a category coherent enough to be meaningfully negated, is "anti-realism". Is this true as well in quantum mechanics?

Neither "local anti-realism" nor "local non-realism" nor permutations of variations thereof return very many search results, certainly many less than "non-local realism" and permutations of variations thereof. Am I using the right terminology for theories that relax various criteria for reality/realism in quantum mechanics? Or is there really just not a whole written on theories that relax the reality criteria?

 

[mjpam]

I am mostly interested in terminology, so I find out about local non-realistic theories. However, given the vagueness of the title, I am open to also discussing the mathematical formalisms that make the idea of realism rigorous and falsifiable.

 

[Nugatory]

"Non-realistic" is a way better term than "anti-realistic"... But if you're looking for search terms, try:

Copenhagen interpretation
Bell's theorem
EPR paradox

And you'll find plenty of material.

 

[Stabilizer]

I have been spending an awful lot of time reading about the philosophy of science where the opposite of "realism", insofar as "realism" constitutes a category coherent enough to be meaningfully negated, is "anti-realism". Is this true as well in quantum mechanics?

Neither "local anti-realism" nor "local non-realism" nor permutations of variations thereof return very many search results, certainly many less than "non-local realism" and permutations of variations thereof. Am I using the right terminology for theories that relax various criteria for reality/realism in quantum mechanics? Or is there really just not a whole written on theories that relax the reality criteria?

You won't find a lot about theories like that because they aren't especially viable. The term "local realism" comes from the assumptions made in Bell's derivation of his orginial inequality. However, as Bell himself pointed out soon afterwards, relaxing the assumption of realism doesn't really change anything.

Most variations on Bell's inequality do not assume realism, and still demonstrate quite clearly that quantum mechanics is nonlocal (barring loopholes).

 

[Demystifier]

I have been spending an awful lot of time reading about the philosophy of science where the opposite of "realism", insofar as "realism" constitutes a category coherent enough to be meaningfully negated, is "anti-realism". Is this true as well in quantum mechanics?

Neither "local anti-realism" nor "local non-realism" nor permutations of variations thereof return very many search results, certainly many less than "non-local realism" and permutations of variations thereof. Am I using the right terminology for theories that relax various criteria for reality/realism in quantum mechanics? Or is there really just not a whole written on theories that relax the reality criteria?

Realism is the idea that, when we make an observation, we observe something that "really" exists even without our observation.

You may also want to read this:
http://xxx.lanl.gov/abs/quant-ph/0607057 [Foundations of Physics, Vol. 37 No. 3, 311-340]

 

[wuliheron]

Realism is the idea that reality exists independent of observers and naive realism is the idea that we perceive objects as they really are. Both are challenged by the experimental evidence of quantum mechanics and it isn't merely a question of local verses nonlocal realism either.

The latest theories and evidence in quantum mechanics suggest reality is contextual, that is, reality has no demonstrable meaning outside specific contexts. For example, whether the Earth looks flat, round, a dimensionless point, or nonexistent just depends on how far way we are. The reality of the Earth's existence then can be said to be context dependent and if it has any reality independent of our context such speculations are outside the purview of science.

 

[MarcoD]

I have been spending an awful lot of time reading about the philosophy of science where the opposite of "realism", insofar as "realism" constitutes a category coherent enough to be meaningfully negated, is "anti-realism". Is this true as well in quantum mechanics?

Neither "local anti-realism" nor "local non-realism" nor permutations of variations thereof return very many search results, certainly many less than "non-local realism" and permutations of variations thereof. Am I using the right terminology for theories that relax various criteria for reality/realism in quantum mechanics? Or is there really just not a whole written on theories that relax the reality criteria?

You're mixing a number of terms. Realism broadly asserts that all that exists includes the observers, materialism broadly asserts that all that is matter or energy -and is a form of realism,- idealism asserts that all is mental, and contrasts realism.

Locality and non-locality are views on whether only local phenomena can explain certain 'linked,' or entangled, quantum states, a side effect of a mathematical theory on minute phenomena in nature.

Most physicist are both realist and materialists. Locality has little to do with either view, so non-local realist asserts someone who favors a certain explanation of quantum phenomena and has a realist/materialist explanation of the world. One might also be a local, or non-local, idealist - locality and realism are orthogonal concepts.

 

[bohm2]

Here are 2 other interesting papers by Gisin on this issue of realism with a few interesting quotes:

For me realism means, very briefly, that physical systems possesses properties preexisting and independent of whether we measure the system or not; however these preexisting properties do not determine measurement outcomes, but only their propensities...

Many physicists, not familiar with Bell inequalities, get scared when one talks about nonlocality and may thus prefer to write “incompatible with local realism”, hoping to avoid nonlocality. From my experience, this is due to a confusion between the kind of nonlocality encountered in quantum physics and the locality condition familiar in relativity. The fact is that nonlocality does not imply the possibility of signalling, i.e. some nonlocal correlations, for instance those predicted by quantum physics, can’t be used to communicate from Alice to Bob, nor from Bob to Alice. Hence no signalling and nonlocality are different concepts, the former is essential for relativity, the later is a well confirmed prediction of quantum physics.

Non-realism : deep thought or a soft option ?
http://arxiv.org/pdf/0901.4255v2.pdf

The answer is that measurement results reflect preexisting properties: this is realism! Simply, the reflection is not a deterministic one, the preexisting properties only determine the propensities, i.e. the natural tendencies, of the different measurement results. Note that this is absolutely compatible with standard quantum mechanics: the probabilities of measurement results are defined by the reduced density matrix. Hence, randomness is not a problem for realism.

Is realism compatible with true randomness?
http://arxiv.org/pdf/1012.2536.pdf

 

[Maui]

The latest theories and evidence in quantum mechanics suggest reality is contextual, that is, reality has no demonstrable meaning outside specific contexts. For example, whether the Earth looks flat, round, a dimensionless point, or nonexistent just depends on how far way we are. The reality of the Earth's existence then can be said to be context dependent and if it has any reality independent of our context such speculations are outside the purview of science.

Ancient and somewhat deficient, but still capturing some of the essences of modern day philosophical conundrums on realism(talking about the Hindu philosophy of Advaita Vedanta):


http://en.wikipedia.org/wiki/Advaita_Vedanta

http://en.wikipedia.org/wiki/Brahman


It doesn't reject materialism and the material world, yet it says it's not completely real in all senses either. And termed as it is, it seems impossible to refute with modern day evidence.

 

[Hurkyl]

I have been spending an awful lot of time reading about the philosophy of science where the opposite of "realism", insofar as "realism" constitutes a category coherent enough to be meaningfully negated, is "anti-realism". Is this true as well in quantum mechanics?

One thing to note is that "realistic" in "locally realistic" is a different word than "realism", and is referring to a different idea. (and, of course, is also a different word from its homonym "realistic" in layman's English)

Realistic interpretations are the exception in quantum mechanics; generally speaking, most scientific material you will read on the topic is not realistic. You have to go out of your way to find realistic interpretations; the most prominent, I think, is Bohmian mechanics.


Roughly speaking, realism says that the quantum state refers in some sense to an actual object in the real world, and that one can do an experiment with it whose outcome we call "position". "Realistic" says that "position" is an actual property of that object, rather than merely an outcome of an experiment.

 

[wuliheron]

Ancient and somewhat deficient, but still capturing some of the essences of modern day philosophical conundrums on realism(talking about the Hindu philosophy of Advaita Vedanta):

http://en.wikipedia.org/wiki/Advaita_Vedanta

http://en.wikipedia.org/wiki/Brahman

It doesn't reject materialism and the material world, yet it says it's not completely real in all senses either. And termed as it is, it seems impossible to refute with modern day evidence.

Science isn't about disproving metaphysical suppositions, the existence of God, or anything else for that matter. Its about what is demonstrable and in the case of metaphysics that means how they can be self-consistent and possibly useful for practical applications. Personally I think all metaphysics is so much gibberish that occasionally turns out to be useful. No more or less meaningful then anything else without a specific context to give them meaning.

 

[Maui]

Science isn't about disproving metaphysical suppositions, the existence of God, or anything else for that matter. Its about what is demonstrable and in the case of metaphysics that means how they can be self-consistent and possibly useful for practical applications. Personally I think all metaphysics is so much gibberish that occasionally turns out to be useful. No more or less meaningful then anything else without a specific context to give them meaning.

I agree with all of what you say, however 'meaning' is as much out of the bounds of science as is the purported existence of god or our attempts at understanding an otherwise incomprehensible reality. While we are at that, everything has become out of the bounds of science and relegated to metaphysics these days(save for a handful of mathematical rules for predictions and a general model of the world that we don't know and understand how to save from becoming ever more phenomenal). If in doubt, ask why this thread got moved here. With that in mind, there is no absolute guarantee that the prevalent methaphysics and models of the world of today will be useful tomorrow and to what extent.

 

[mjpam]

Thanks for all of the responses.

I have busied myself reading some of the publication provided, and am trying to formulate a explanation that refines the questions I asked in the OP.

 

[wuliheron]

I agree with all of what you say, however 'meaning' is as much out of the bounds of science as is the purported existence of god or our attempts at understanding an otherwise incomprehensible reality. While we are at that, everything has become out of the bounds of science and relegated to metaphysics these days(save for a handful of mathematical rules for predictions and a general model of the world that we don't know and understand how to save from becoming ever more phenomenal). If in doubt, ask why this thread got moved here. With that in mind, there is no absolute guarantee that the prevalent methaphysics and models of the world of today will be useful tomorrow and to what extent.

Meaning can be as demonstrable as anything else and well within the bounds of science. Being a pragmatist myself I couldn't care less what science adopts and discards so long as it is useful at the time. For all I know that is the fate of science, to constantly evolve along with its context. In fact, the alternative sounds rather unappealing.

 

[Maui]

Meaning can be as demonstrable as anything else and well within the bounds of science.

That 'meaning' can mean very different things to different people. It's not known to me that there exists anything at all in this reality that has an inherent meaning. On the contrary, we give everything we do meaning, in other words, meaning in and of itself DOES not exist. Hence, science cannot discuss meanings, because scientists and people give meaning to the studied subjects. In that respect, meaning is very different than mass, velocity, charge and other observable characteristics.

Being a pragmatist myself I couldn't care less what science adopts and discards so long as it is useful at the time. For all I know that is the fate of science, to constantly evolve along with its context. In fact, the alternative sounds rather unappealing.

I am not aware of there having ever been a greater confusion in the minds of scientists wrt to the world at large, than that of today(maybe in the stone age?). While i find it more likely that reality wasn't designed(based on the fact that most of things in the past that looked designed were found to not be), i can't completely hand-wave arguments to the contrary, as science is plagued with deep conceptional problems - from who/how/what makes decisions in neural circuits in the brain(neurons firing), to the nature of matter, time and space(and even who and what exists). I don't know of a single category of our scientific enquiries whose validity hasn't been questioned by authorities in theor fields(that sadly includes realism in all of its varieties). In that respect, i find the ideas in the ancient Hindu philosophies i linked above more flexible and slightly more compatible with the requirements of no-go theorems than the rock-solid stereotype of the world found among pedestrians on the street. And let's face it, if the wave nature of matter turns to be real(as in the sense of realism as it is generally understood by physicists), this will be a very big, if not the biggest, challenge facing physics and physicists(a nasty surprize too).

 

[wuliheron]

That 'meaning' can mean very different things to different people. It's not known to me that there exists anything at all in this reality that has an inherent meaning. On the contrary, we give everything we do meaning, in other words, meaning in and of itself DOES not exist. Hence, science cannot discuss meanings, because scientists and people give meaning to the studied subjects. In that respect, meaning is very different than mass, velocity, charge and other observable characteristics.

It doesn't matter whether people have two different meanings or whatever. Science is only interested in what is demonstrable and if it can be demonstrated they have two different meanings that's good science. Essentially no different then a dictionary having multiple definitions for the same word, yet people manage to communicate effectively nonetheless.

I am not aware of there having ever been a greater confusion in the minds of scientists wrt to the world at large, than that of today(maybe in the stone age?). While i find it more likely that reality wasn't designed(based on the fact that most of things in the past that looked designed were found to not be), i can't completely hand-wave arguments to the contrary, as science is plagued with deep conceptional problems - from who/how/what makes decisions in neural circuits in the brain(neurons firing), to the nature of matter, time and space(and even who and what exists). I don't know of a single category of our scientific enquiries whose validity hasn't been questioned by authorities in theor fields(that sadly includes realism in all of its varieties). In that respect, i find the ideas in the ancient Hindu philosophies i linked above more flexible and slightly more compatible with the requirements of no-go theorems than the rock-solid stereotype of the world found among pedestrians on the street. And let's face it, if the wave nature of matter turns to be real(as in the sense of realism as it is generally understood by physicists), this will be a very big, if not the biggest, challenge facing physics and physicists(a nasty surprize too).

Habits are the end of compassion and honesty,
The beginning of confusion;
Lao Tzu

I couldn't care less about the "reality of the matterwave" or whether scientists are confused or Joe sixpack is shallow or Hinduism can make the world a better place or whatever. Metaphysics, theology, and psychology are not branches of physics and the only issue on the table is what the physics of quantum mechanics has to say about realism.

Please stick with the topic.

 

[Maui]

Metaphysics, theology, and psychology are not branches of physics and the only issue on the table is what the physics of quantum mechanics has to say about realism.

Please stick with the topic.

I hate to point out this obvious fact, but if the topic landed here, it obviously(physics) didn't have much to say about realism. I am also certain that anytime you or anyone else discussed propositions about realism in pseudo-physics terms(you couldn't in any other way), the topic would be moved to personal philosophies(i.e. here). You have to be aware of the difference between physics and metaphysics and when one turnes into the other.

 

[wuliheron]

I hate to point out this obvious fact, but if the topic landed here, it obviously(physics) doesn't have much to say about realism. I am also certain that anytime you or anyone else discusses propositions about realism in pseudo-physics terms(you couldn't in any other way), the topic will be moved to personal philosophies(i.e. here).

Physics deals with what is demonstrable and can therefore describe whether the accepted theories and evidence appear to be particularly compatible or incompatible with any metaphysics.

 

[Maui]

Physics deals with what is demonstrable and can therefore describe whether the accepted theories and evidence appear to be particularly compatible or incompatible with any metaphysics.

Going by this rule, realism at the quantum level can be considered dead. My own opinion changed a few times through the years on this, based entirely on my own philosophical considerations. To my knowledge, the best test of quantum realism has been carried out by Nobel Prize winner A.Legget and Zeilinger in 2007:

"It took them months to reach their tentative conclusion: If quantum mechanics described the data, then the lights’ polarizations didn’t exist before being measured. Realism in quantum mechanics would be untenable."

"A team of physicists in Vienna has devised experiments that may answer one of the enduring riddles of science: Do we create the world just by looking at it?"
http://seedmagazine.com/content/article/the_reality_tests/P1/


“But to give up on realism altogether is certainly wrong. Going back to Einstein, to give up realism about the moon, that’s ridiculous. But on the quantum level we do have to give up realism.”"

This is very puzzling, how can classical realism survive if quantum realism failed?



Also, this paper and test by A.Zeilinger claims to show that which-path information changes which aspect of matter will be observed(wave-like or particle-like) which would be direct demonstration that a mind-independent world does not exist(since mind and information, which is solely a property of minds, affects the behavior of matter at the micro scale):

http://www.google.com/url?sa=t&rct=...7pStCA&usg=AFQjCNH5quntpOPVJgVTo6Tkw--isU1BUA

 

[wuliheron]

Just because realism is all but dead in quantum mechanics doesn't mean panpsychism or whatever is the most likely alternative. Before his death John Wheeler suggested a theory of everything might turn out to be just an equation with no clear metaphysical underpinnings whatsoever. It ain't over until the fat lady sings and right now we have plenty of other evidence for other metaphysical positions as well.

 

[Maui]

Just because realism is all but dead in quantum mechanics doesn't mean panpsychism or whatever is the most likely alternative. Before his death John Wheeler suggested a theory of everything might turn out to be just an equation with no clear metaphysical underpinnings whatsoever. It ain't over until the fat lady sings and right now we have plenty of other evidence for other metaphysical positions as well.

I am not aware of any methaphysical models that do not employ realism(and are embraced by physicists). Except to some extent solipsism which is a more favorable outcome to some than the alternative. There exist some other propositions that are so vague, that they purposefully don't contain any metaphysics at all and the reader is left to make up their minds on their own. A failure of realism is also a failure of our concept of the world and what it is. As Aspect points out “QM implies renouncing the kind of realism I would have liked”.

 

[wuliheron]

I am not aware of any methaphysical models that do not employ realism(and are embraced by physicists). Except to some extent solipsism which is a more favorable outcome to some than the alternative. There exist some other propositions that are so vague, that they purposefully don't contain any metaphysics at all and the reader is left to make up their minds on their own. A failure of realism is also a failure of our concept of the world and what it is. As Aspect points out “QM implies renouncing the kind of realism I would have liked”.

There are also contextualists who believe the question meaningless to begin with. Along the lines of asking what is the color of music or what is the sound of one hand clapping. At any rate that is, yet again, outside the purview of physics.

 

[fuzzyfelt]

I'm enjoying this. Which contextualists, Wuliheron?

 

[wuliheron]

I'm enjoying this. Which contextualists, Wuliheron?

I'd start with Wittgenstein and go from there.

 

[fuzzyfelt]

Thanks for the response, but my question should have been more precise, because I was wondering if you'd recommend any particularly interesting, very recent work on that topic, or more broadly the OP topic, just because you'd mentioned latest ideas earlier in the thread.

 

[mal4mac]

In modern philosophy "realism" is contrasted with "idealism". Realism is the view that physical objects exist without being perceived - the standpoint of "common sense". Idealists, starting with Berkeley, were puzzled how perceptions could yield knowledge of a mind-independent world. Perceptions, after all, are dependent on the mind for any perception to happen!

Another big figure here is Kant, who influenced Einstein and many others. So you might get somewhere searching for "idealism quantum mechanics", "Kant quantum mechanics", and so on...

 

[Maui]

There are also contextualists who believe the question meaningless to begin with. Along the lines of asking what is the color of music or what is the sound of one hand clapping. At any rate that is, yet again, outside the purview of physics.

Sounds like an instrumentalist approach to me(giving up right where the interesting stuff begins, which would be counter to philosophical thought). Anyway, I think the basic concepts were clear as early as the first double slit experiment and the birth of the theory and the subsequesnt EPR argument. Classicality emerges as an interaction(the reduction of the state vector, with the apparent instantaneous transition from delocalized wave-like quantum behavior to localized, detected classical-like "particle"-like behavior). It stands to reason, that anytime one reaches for the door, classical-like behavior is expected(from particle-like entities) and a 3D door is expected to be found. This doesn't mean that a localized door in space and time exists without interaction and one's attention. To the contrary, the fullerenes double slit experiment appears to point otherwise - if the authors are right and the experiment received enough attention to warrant this, the door is delocalized and more akin to a tendency in the absence of interaction and information extraction. In that respect, I don't understand what people mean when they speak of quantum realism and where it's supposed to be found.

I am also wondering what contextualists imagine the context to be(since you use a well defined concept like 'context')? Your inquiry or just inquiry in general?

 

[Maui]

I have been spending an awful lot of time reading about the philosophy of science where the opposite of "realism", insofar as "realism" constitutes a category coherent enough to be meaningfully negated, is "anti-realism". Is this true as well in quantum mechanics?

It's more like what we can say and infer about quantumness, which would be a category opposed to realism, if one didn't wish to introduce new imaginary concepts. Quantumness is about as counter to realism as it gets without going too deep in the philosophical side of things.

 

[wuliheron]

Thanks for the response, but my question should have been more precise, because I was wondering if you'd recommend any particularly interesting, very recent work on that topic, or more broadly the OP topic, just because you'd mentioned latest ideas earlier in the thread.

I'm sorry to say I don't know of any interesting up to date works on the subject. Contextualist theories are just beginning to establish themselves and the evidence is still pouring in at a brisk pace. Photosynthesis and animal navigation abilities that apparently can only be explained by room temperature entanglement for example. Physicists are rediscovering the world all over again and often feeling a bit humbled by it being oh so much more complex then they imagined as well as excited at the prospects. Not unlike the transition we went through from Newtonian mechanics to modern physics.

 

[wuliheron]

Sounds like an instrumentalist approach to me(giving up right where the interesting stuff begins, which would be counter to philosophical thought).

That's a common assessment of contextualism by continental philosophers. However, it goes way beyond merely instrumentalist views because it insists even instrumentalism is context dependent.

Anyway, I think the basic concepts were clear as early as the first double slit experiment and the birth of the theory and the subsequesnt EPR argument. Classicality emerges as an interaction(the reduction of the state vector, with the apparent instantaneous transition from delocalized wave-like quantum behavior to localized, detected classical-like "particle"-like behavior). It stands to reason, that anytime one reaches for the door, classical-like behavior is expected(from particle-like entities) and a 3D door is expected to be found. This doesn't mean that a localized door in space and time exists without interaction and one's attention. To the contrary, the fullerenes double slit experiment appears to point otherwise - if the authors are right and the experiment received enough attention to warrant this, the door is delocalized and more akin to a tendency in the absence of interaction and information extraction. In that respect, I don't understand what people mean when they speak of quantum realism and where it's supposed to be found.

I am also wondering what contextualists imagine the context to be(since you use a well defined concept like 'context')? Your inquiry or just inquiry in general?

There isn't just one type of contextualism anymore then there is just one type of realism. What they all have in common is an emphasis on the importance of context in solving problems or establishing meaning. A race has ensued to created a well established theory of linguistics to determine exactly what contextualists mean by context and so far Functionalist views are the first of any philosophy to at least flirt with creating an accepted scientific theory of linguistics. Still, progress in philosophy tends to be slower then other disciplines and it might be another century before linguistics becomes an established science based on first principles.

 

[fuzzyfelt]

I'm sorry to say I don't know of any interesting up to date works on the subject. Contextualist theories are just beginning to establish themselves and the evidence is still pouring in at a brisk pace. Photosynthesis and animal navigation abilities that apparently can only be explained by room temperature entanglement for example. Physicists are rediscovering the world all over again and often feeling a bit humbled by it being oh so much more complex then they imagined as well as excited at the prospects. Not unlike the transition we went through from Newtonian mechanics to modern physics.

Ok, thanks, wuliheron. I've seen and think I've mentioned this sort of notion in other contexts ((:), but hadn't seen much applied in this one, too.

 

[wuliheron]

Ok, thanks, wuliheron. I've seen and think I've mentioned this sort of notion in other contexts ((:), but hadn't seen much applied in this one, too.

Yeah, it adds new meaning to "quantum weirdness" to assume they are contextual and forces people to re-evaluate their behavior in every context including classical ones.

 

[fuzzyfelt]

Very fascinating thoughts, indeed!