To illustrate why it’s complicated, let me remind you of an experiment we already talked about in a previous video. Suppose you have a particle with total spin zero. The spin is conserved and the particle decays in two new particles. One goes left, one goes right. But you know that the two new particles cannot each have spin zero. Each can only have a spin with an absolute value of 1. The easiest way to think of this spin is as a little arrow. Since the total spin is zero, these two spin-arrows of the particles have to point in opposite directions. You do not know just which direction either of the arrows points, but you do know that they have to add to zero. Physicists then say that the two particles are “entangled”.
The question is now what happens if you measure one of the particles’ spins. This experiment was originally proposed as a thought experiment by Einstein, Podolsky, and Rosen, and is therefore also known as the EPR experiment. Well, actually the original idea was somewhat more complicated, and this is a simpler version that was later proposed by Bohm, but the distinction really doesn’t matter for us. The EPR experiment has meanwhile actually been done, many times, so we know what the outcome is. The outcome is... that if you measure the spin on the particle on one side, then the spin of the particle on the other side has the opposite value. Ok, I see you are not surprised. Because, eh, we knew this already, right? So what is the big deal?
Indeed, at first sight entanglement does not appear particularly remarkable because it seems you can do the same thing without quantum anything. Suppose you take a pair of shoes and put them in separate boxes. You don’t know which box contains the left shoe and which the right shoe. You send one box to your friend overseas. The moment the friend opens their box, she will instantaneously know what’s in your box. That seems to be very similar to the two particles with total spin zero.
But it is not, and here’s why. Shoes do not have quantum properties, so the question which box contained the left shoe and which the right shoe was decided already when you packed them. The one box travels entirely locally to your friend, while the other one stays with you. When she opens the box, nothing happens with your box, except that now she knows what’s in it. That’s indeed rather unsurprising.
The surprising bit is that in quantum mechanics this explanation does not work. If you assume that the spin of the particle that goes left was already decided when the original particle decayed, then this does not fit with the observations.
The way that you can show this is to not measure the spin in the same direction on both sides, but to measure them in two different directions. In quantum mechanics, the spin in two orthogonal directions has the same type of mutual uncertainty as the position and momentum. So if you measure the spin in one direction, then you don’t know what’s with the other direction. This means if you on the left side measure the spin in up-down direction and on the right side measure in a horizontal direction, then there is no correlation between the measurements. If you measure them in the same direction, then the measurements are maximally correlated. Where quantum mechanics becomes important is for what happens in between, if you dial the difference in directions of the measurements from orthogonal to parallel. For this case you can calculate how strongly correlated the measurement outcomes are if the spins had been determined already at the time the original particle decayed. This correlation has an upper bound, which is known as Bell’s inequality. But, and here is the important point: Many experiments have shown that this bound can be violated.
And this creates the key conundrum of quantum mechanics. If the outcome of the measurement had been determined at the time that the entangled state was created, then you cannot explain the observed correlations. So it cannot work the same way as the boxes with shoes. But if the spins were not already determined before the measurement, then they suddenly become determined on both sides the moment you measure at least one of them. And that appears to be non-local.
So this is why quantum mechanics is said to be non-local. Because you have these correlations between separated particles that are stronger than they could possibly be if the state had been determined before measurement. Quantum mechanics, it seems, forces you to give up on determinism and locality. It is fundamentally unpredictable and non-local.
Ok, you may say, cool, then let us build a transmitter, forget our frequent flyer cards and travel non-locally from here on. Unfortunately, that does not work. Because while quantum mechanics somehow seems to be non-local with these strong correlations, there is nothing that actually observably travels non-locally. You cannot use these correlations to send information of any kind from one side of the experiment to the other side. That’s because on neither side do you actually know what the outcome of these measurements will be if you chose a particular setting. You only know the probability distribution. The only way you can send information is from the place where the particle decayed to the detectors. And that is local in the normal way.
So, oddly enough, quantum mechanics is entirely local in the common meaning of the word. When physicists say that it is non-local, they mean that particles which have a common origin but then were separated can be stronger correlated than particles without quantum properties could ever be. I know this sounds somewhat lame, but that’s what quantum non-locality really means.
Having said this, let me add a word of caution. The conclusion that it is not possible to explain the observations by assuming the spins were already determined at the moment the original particle decays requires the assumption that this decay is independent of the settings of the detectors. This assumption is known as “statistical independence”. If is violated, it is very well possible to explain the observations locally and deterministically. This option is known as “superdeterminism” and I will tell you more about this some other time.
Hi, Wasn't it BohM rather than BohR who devised the variant of EPR using spin angular momentum? Perhaps it's a typo in the transcription...
ReplyDeleteAh, dammit, you are right of course. Unfortunately, it's not merely a typo :(
DeleteThe paradox appears because of the mixing of classical pictures and language with quantum computation. An example is: "the moment the original particle decays". Instead of two "particles" one has an experiment yielding a result in a more complicated configuration space.
ReplyDeleteThe language is not the issue here. Just like Bohr said, the results of any experiment must be described in "classical" language. In the end you have two data columns that need to be explained. And, as EPR proved, the only way to explain them, and hence solve the paradox, is by accepting either non-locality or determinism. Bell refined this result, showing that only a certain type of deterministic theory, the so-called "superdeterministic" are possible.
DeleteNietzsche introduced the idea of perspectivism: in the final analysis, all we really have is a manifold of interlocking perspectives. For example, consider the following toy model. If humans are small finite, represent each possible human perspective by a small non-empty subset of {1,...,n} where n is a large natural number. Then, there are minimal perspectives, but no maximal human perspective. Still, there is an ideal finite perspective which sees everything! If n=infinity, then there is still an ideal infinite perspective which sees everything! (God's eye-view!) If one accepts the standard quantum logic, then one has a manifold of perspectives which cannot-by Gleason's Theorem-be embedded into any single perspective! There are now maximal perspectives, but no universal perspective!
DeleteThe classical language such as the one I referenced is not describing the results of an experiment but "the world" behind the experiment! That's where the problem lies!!
DeleteProf. David Edwards,
Delete"Standard quantum logic" is not a different kind of logic. It's the same logic applied to real experimental situations. In real situations there are no multiple perspectives. There is only one perspective that is worth speaking about, the one that describes the experiment that was actually performed. If you measure the X-spin, you cannot simultaneously measure the Y-spin, you cannot have a magnet aligned with two axes at the same time. So, in the language of the consistent histories approach, the X-framework is the only one that is meaningful. So, the Y-framework (or perspective) is irrelevant, it does not correspond to reality.
The fact that you cannot combine X and Y perspectives it is to be expected even in a classical world.
@ Andrei,
DeleteFor me quantum logic is just generalized probability theory containing incompatible observables. The perspectives are sub-Boolean algebras of the quantum logic. Incompatible perspectives are, of course, not compatible; they are potential perspectives.
Prof. David Edwards,
Delete"Incompatible perspectives are, of course, not compatible; they are potential perspectives."
True, but then you said:
"There are now maximal perspectives, but no universal perspective!"
Why, even in a classical world would you expect to have an universal perspective that contains all potential perspectives? It seems to me that the universal perspective need only contain the actual facts, not the potential ones that never get realized, right?
@ Andrei
DeleteMy language above is short and informal; for full details of a completely coherent approach to quantum theory see my essay "The Mathematical Foundations of Quantum Mechanics" on my website.
P.S. In a classical world there is a world and a God's Eye view of it!
Prof. David Edwards5:28 AM, June 03, 2020
Delete'see my essay "The Mathematical Foundations of Quantum Mechanics"'
Can this idea tell us what will appear on the physicists' gauges in experiments better than other theories predict, or is it another "interpretation" of quantum mechanics to add to the collection?
The intuitions of our brains are probably best not to be overly trusted. Can you predict what will appear on the gauges in experiments better than anyone else? That's all that counts.
Also, reading philosophers like Nietzsche will not lead to knowledge about Physics. These people witter on about the state of their minds which are completely muddled because they never studied any natural science. You might as well read someone's description of an acid trip.
@ Steven Evans,
DeleteMy essay is a synthesis of Bohr and von Neumann while avoiding all their confusions!
I’m not sure if I understand a part of the explanation that tells us why assuming the spin of the two separated particles cannot be predetermined at the point of separation like the pair of shoes. What I think I do understand:
ReplyDelete1. One goes left one goes right (left-right, or up-down, etc.), the total spin must remain zero.
2. There is no correlation for spin measured in two Orthogonal directions sticking with left-right, up-down as a reference you can have left -1, up -1, or left 1- up 1, etc. no correlation between the two directions we just know that if left is -1 the other particle that goes right must be 1 and the sum must be zero.
3. You could calculate a correlation for #2 if the spins were determined at the time of separation with an upper bound (Bell’s inequality) and many experiments have shown that bound can be violated.
Is it just because Bells inequality can be violated if the spin was pre-determined that we can’t assume there was a spin state the time of separation? In other words Bell’s inequality only works with observations if you don’t pre-determine spin states and fails if you do, it’s why we can’t assume spin states are pre-determined at particle separation?
Yes, exactly! (Assuming statistical independence is valid, as I say in the end.)
DeleteHi Sabine,
ReplyDeleteThis is an excellent introduction to quantum non-locality!
At the end you mention superdeterminism as an alternative to superluminal "spooky action". I just wanted to remind readers that superdeterminism is both: (a) a common belief among relativistic and quantum physicists, and (b) frequently scoffed at by the same people who believe it.
Uh... what?
The source of this oddly paradoxical situation is that anyone who believes in Einstein's concept of a block universe — that is, a universe in which all world lines are predetermined and unchangeable from the beginning to the end of time — is necessarily and unavoidably also a superdeterminist.
Why? The reason is oddly simple: If spooky action exists within any block universe, then the behaviors of quantum experimenters and the outcomes of their quantum experiments must necessarily be pre-correlated to ensure the observed spooky action outcomes. This level of predetermined correlation between classical human behaviors and quantum outcomes is the definition of superdeterminism. The bottom line is that since block universes predetermine everything, superdeterminism cannot be avoided if spooky action is also permitted.
Given the simplicity of this point, I find it delightful that many who firmly believe in the block universe tend to dismiss superdeterminism as “going too far”. Such dismissals just mean they have never fully thought through the implications of adding experimentally observable spooky action at a distance to a universe of predetermined worldlines. Physicist, grill thyself!
Terry,
DeleteThe whole point of superdeterminism is to do without "spooky action at a distance".
The FQXi contest on undecidability in physics lead me to consider how nonlocality of QM a result of undecidability of the same fractal system you and Palmer consider. Palmer appeals to a somewhat different definition of undecidability, but in effect I think the same outcome happens. The superdeterminism is itself not decidable, which in the sense of undecidability → unobservability means there is no measurable content to superdeterminism. It is then just a mathematical gadget used to understand QM.
DeleteThis would mean the independence vs dependence of statistics in QM is also not decidable. I think it is something we can never know. In effect it would mean if there is a statistical dependency it relies upon nonlocal hidden variables that we can never observe. I think in a way we are as Led Zeppelin put it, “Back to the same old jam.” To appeal to statistical dependence is not that different then from choosing some type of quantum interpretation.
Terry Bollinger used the phrase "universe of predetermined worldlines"
DeleteNature performs an amazing feat of bookkeeping. No charge or unit of angular momentum was ever found lost. But she probably does not use the anthropocentric way of connecting events by worldlines. The identity of particles would be difficult to understand if Nature really did keep track "which" electron interacted with "which" photon. If QED can be a guide, it must be an extremely non-local way in which all possible ways to connect vertices contribute, each with their specific amplitudes.
Good point. Poorly chosen labels can bias our perceptions in subtle ways. There are no New World camels not due to any lack of New World camels, but because history labeled them llamas, alpacas, vicuñas, and guanacos.
DeleteThe phrase “spooky action at a distance” necessarily presumes action, and thus non-locality. A better phrase might be “anomalous correlations”, correlations that appear to violate speed of light constraints. Spooky action resolves anomalous correlations by violating locality, while superdeterminism preserves locality.
This resembles mathematician joke about their attitudes to the axiom of choice which is obviously true while the well ordering theorem is obviously false, and no one is quite sure what to make of Zorn's lemma. All three are equivalent.
DeleteThe axiom of choice and well ordering are the same thing. The axiom of choice is that a set can be well ordered. With all of this about undecidability and its putative connection to uncertainty, I have looked a bit into this. I read my copy of Wagon’s book The Banach-Tarski Paradox, where the axiom of choice leads to an odd duplication of spheres or that a ball the size of Earth can be decomposes and reassembled into one that would fit into an atom. The axiom of choice leads to some odd things. This is a fairly straight forwards axiom, at least at first blush, and set theory without it is in other ways less plausible --- though it can be used to connect game theory to set theory.
DeleteAs a mathematician I know put it,” Set theory is set on your ass theory.” I can in some ways see this objection to this whole subject. It is an area of math that becomes quickly mired in matters of undecidability, as does the continuum hypothesis, so that we become somewhat lost. As a rule, I do tend to prefer more standard mathematics with algebra, geometry, number theory etc.
The complement of a fractal set is undecidable. A fractal set is recursively enumerable, which means we can compute it in a finite automata up to some point, and “in principle” a Turing machine that runs eternally could compute the whole thing. The complement of this is not computable. The complement of a recursive set is recursive, but the complement of a recursively enumerable set is not recursively enumerable and is incomputable. This invariant set theory of Palmer and Hossenfelder as a means of connecting nonlinearity with QM is interesting. The approach with Cantor sets connects with incomputability. I prefer a more standard definition of incomputability than what P&H appeal to.
I have found, with a fair amount of ancillary assumptions, that QM can be connected with the Mandelbrot set in a nonlinear setting. I was hoping to find the logistic map but found something much deeper. Beside the logistic map is connected to the Mandelbrot set anyway. The Mandelbrot set is sort of the “ultimate fractal,” for the Hausdorff dimension of the boundary is 2 – ε for lim ε → 0. The fractal is so “wild” the boundary of a 2 dimensional region is effectively 2 dimensional.
This is all interesting to ponder. I am still fiddling with this and hope I am not making some bad mistake. There are issues of the axiom of choice of course lurking here. I would say this is primarily with the complement of the set. In those pretty videos of zooming into the Mandelbrot set those colorized regions are the complement, while the blackened parts are the actual set.
Hi Kaleberg,
DeleteWell put! Now, given my earlier nomenclature example for the four varieties of New World camelids called llamas, guanacos (wild llamas), alpacas, and vicuñas (wild alpacas), I can only make this observation:
The axiom of choice when buying a camelid is obviously true; the well ordering theorem that you can order your camelid go to a well and make it drink from it is obviously false; and when attempting to draw the Hasse domestication diagram for the exceptionally unruly camelid that Max Zorn once bought in South America, no one is quite sure what to make of Zorn’s llama.
Lawrence,
DeleteRe Lawrence Crowell 8:07 AM, May 31, 2020:
Underlying relationships (laws of nature) seem to exist in the world, which are representable by equations. The colourful/black evolving Mandelbrot set representation is arrived at mainly by algorithmic steps, with very little actual equation content. If the Mandelbrot set says something about the world, then aren’t you saying that algorithmic steps, i.e. something very different to equations, are needed to represent the world as an evolving system?
The equation is an iterated map, which is a form of dynamics. The Schrödinger equation within a type of perturbation series can give nonlinear iterated maos. The map for the Mandelbrot set can emerge. This is a case of QM becoming nonlinear, where the quantum wave in effect ceases to exist in a unitary equivalent form. The complement of the fractal set, a recursively enumerable set, is not Turing computable.
DeleteTo put it another way Lawrence:
DeleteTry to represent the dynamics of the world without (you with pen and paper, or a computer) using any “steps”. You can’t. To represent the world, you need both 1) the lawful relationships between categories of variable; and 2) “steps”. You are merely confirming that “steps” are necessary to make the world work, just like “steps” (taken by you with pen and paper, or a computer) are necessary to make the Mandelbrot set representation.
Greetings Werner,
DeleteWith regards to my phrase “universe of predetermined worldlines,” you observed (paraphrasing) that “no charge or unit of angular momentum is ever lost”, and that “nature probably does not use anthropic worldlines [because] QED [tells us vertices contribute amplitudes in] extremely non-local ways.”
As someone with a lifelong interest in cognition, I’ve always had available to me a superb example of how badly human cognition can fail: me.
That’s humbling. For example, at some point I discovered to my sincere shock that simply feeling I was correct had nothing to do with whether I was correct. To help counter this, I try to understand and promote as seriously as I can well-reasoned views with which I disagree.
So, and as most regulars here already know, not only am I not a superdeterminist, I’m about as far towards the other end of the quantum interpretation spectrum as a person can go. I place non-locality first, and view both locality and classicalism as inherently imprecise phenomena that emerge from the quantum world through multiple levels of “persistence,” information, what we so casually call “bits” — ordinary bits, not quantum bits. Such “ordinary” bits are at the physics level deeply complex phenomena, chaotically unbalanced quantum conservation pairs to be more precise. However, we have difficulty seeing this complexity because like fish in the ocean we swim and exist almost entirely in universe that at multiple scales is filled to overflowing with just such bits. This emergent classical reality becomes “real” to us only after its objects acquire sufficient mass-energy to make classical concepts such a “worldlines” look infinitely precise and predictable, which in turn makes them simple enough for our limited biological processing capacities to handle during an emergency.
In short, if a tiger is attacking, we like our rocks to go where we throw them.
Thus I very much agree with your points even as I argue in favor of the delightful internal consistency of superdeterminism. Plus I always like making the point that superdeterminism is more widely accepted than folks realize, since it is inherent in assuming a block universe. (How is that even radical? “Block universe” means everything is preexistent, including all correlations. Again, duh!)
Also, as you aptly noted, it has been experimentally demonstrated that conservation is the most persistent and unforgiving feature of the natural universe. This includes conservation of spin, charge, angular momentum, linear momentum, and of course mass-energy. Every variant of entanglement boils down at some point to this experimentally well-verified assertion: The ledger book of the universe never forgives even the smallest debt, no matter how distant in space or time.
In sharp contrast to the principle of conservation, the universe refuses to make the concept of a worldline anything more than an approximation whose precision is proportional to the mass-energy of the object in question. Thus massive neutron stars sketch out exquisitely precisely worldlines through space and time, while individual lightweight photons have all-available-information wave functions (and thus worldlines) that can easily spread out over tens of billions of light years. Pilot waves postulate that a precise trajectory photon particle trajectory nonetheless exists within such a wave, yet to this day there is precisely zero experimental evidence that a particle is ever anything more than wave packet whose maximum compactness is limited by total available mass-energy.
Thus while I deeply respect superdeterminism, I don’t go that path myself because I’ve never seen evidence that its most fundamental building block, the concept of a worldline, is anything more than an approximation whose resolution is proportional to the finite mass of the object. Worldlines thus are sand, and one cannot build an edifice as remarkable as the universe upon sand.
Terry Bollinger wrote: "one cannot build an edifice as remarkable as the universe upon sand"
DeleteHi Terry,
I'm not so ambitious as to build an entire universe, but only to understand quantum theory as applied to a tiny path of spacetime, e.g. a laboratory, or the interior of a star. And rather than "explaining" the events, I'd be happy to merely find a consistent statistical description of them. The particle (worldline) concept that has explained so many things, has also led us to contradictions, into the morass of interpretations of QM. This means that the "explanations", though not useless, are fundamentally flawed (as I tried to explain in another comment).
The remedy I have in mind is radical and embarrassingly simple: replacing the worldlines by dotted lines. Just scatter grains of sand (events) over the spacetime continuum! Events can form very intricate patterns that sometimes resemble lines (particles) or waves. (And sometimes tigers!) For electrons we know the scale at which they disappear and reappear: zeptoseconds. If you try observations on that scale you'd be creating new pairs. The difference between water vapour and a mixture of hydrogen and oxygen is just different regularities in the distribution of atoms. Unfortunately my grasp of the mathematics of point processes is just too feeble to derive QFT from it.
Incidentally, the idea isn't new at all. H.G.Wells wrote (1931):
"It may be that we exist and cease to exist in alternations, like the minute dots in some forms of toned printing or the succession of pictures on a cinema film. [...] We may be only a story written on a ground of inconceivable realities, the pattern of a carpet beneath the feet of the incomprehensible."
He must have thought of the block universe too.
Lawrence,
DeleteYou are part of the mathematics of your symbolic model. You can’t extract a human self from the symbols: you animate the model or the symbols. It is not true that a model or an equation (spoken, written on paper, or represented in a computer) is a self-actualising thing or “a form of dynamics” [1]. You are doing it: any steps you take, or you cause a computer model to take, are part of the model.
1. “The equation is an iterated map, which is a form of dynamics”, Lawrence Crowel 6:16 AM, June 02, 2020
Hi Werner,
DeleteYou proposed the intriguing interpretation of worldlines as a “… scatter[ing] … of sand (events) over the spacetime continuum … [to] … form very intricate patterns that sometimes resemble lines (particles) or waves. (And sometimes tigers!)”
I like that. When I say the classical universe is comprised of an ever-increasing (entropic) collection of bits, every such bit descends from some earlier quantum wave collapse event, one that further restricted the range of possible futures. Mathematically that’s essentially identical to MWI, except that no other universes branch off when such events occur. Quantum collapse in this view is not only real, it is the bit generator and thus literal foundation of classical, causal, time-based, speed-of-light bound reality.
So, in your dot-matrix-printer reality (so I’m old!), a piece of thermal matter would be as you just described: An astonishing and never-ending dance of self-collapse and self-observation events, so dense that to us it appears smooth in both space and time. It only gets weird when self-observation (which to me is just irreversible “chaotization” of half of a conserved pair, usually just a good ol’ action-reaction momentum pair) becomes very sparse due to low density of observation-capable complex matter. (Note that not all thermally complex matter is observation-capable. That is why you can read this via photons passing coherently, quantumly, through your cornea and eye lens.) For certain cases — with my favorite experimentally observed example being those tens-of-billions-of-years old photons from the other sides of Einstein lenses — your dots of worldline “sand” (I love that imagery!) become sparse indeed!
Now, with that said, here’s the caution: there is a danger of thinking that the paths of the universe are defined only by such highly localized wave-collapse or “observation” events, and that is simply not the case. Wave functions need not collapse to become part of recorded history. Huh?
How far are you from the center of the earth right now? A bit less than 6.4 megameters? (Wow, I just Googled it, and yes, this unit does exist. Plus it’s better than saying “kilo-km”, which is what I almost said, yes?) The reason I bother to point this out is that you need to thank a gazillion or so extremely collapse-resistant electron wave orbitals for keeping you up that high, and thus not being part of a very boring black hole. If you look in a mirror you can thank uncollapsed photon wave functions for giving you a meaningful image. The fact that the photons must collapse when they reach your retina doesn’t take away from that fact that to form the image, they had to operate in uncollapsed wave mode.
Because we are information beings, we are also information biased. We tend to think of the pre-observation aspects of quantum mechanics as “less real” than the information-generating outcomes of collapse events. But the reality is much more subtle and composite than that! It is an eternal and unendingly complex dance of the known and the unknowable, of incredibly dense fabrics of thermal information (heat) that are interwoven at every level with utterly recalcitrant and uncollapsible wavefunctions, mostly those of electrons and sometimes of photons. These waves provide things like volume, shape, bonding, and in general complexity, and thereby carry reality forward in the gaps between the more isolated sand grains of information-creating events.
But these waves do far more than just passively preserve! They guide the probability functions of what can and cannot emerge, starting at the levels of nuclear and elemental chemistry and extending open-ended to ever higher levels of complexity. It is the uncollapsed wavefunctions that cause the sands of existence to weave themselves into genuinely interesting phenomena…
Such as life itself, and the ability to ask such questions.
Hi Terry,
Deleteyes, I am a bit less than 6.4 Mm away from the centre of the earth. (I'm not aboard the ISS. :-)
It is amazing that these tiny electrons can exert such fantastic pressure. As we know, also the strongest steel is to more than 99.9% empty space! Are you saying that it is not the electrons, but the space-filling wave functions that exert the pressure? And for you time is much more than a coordinate in the block universe, right?
I agree that physics can't end with the pronouncement that the universe "is made of" events. It is the correlations, the patterns formed by these sand grains that are interesting. Like letters of the alphabet, they combine to form words, sentences, tales ...
@Werner:
DeleteI was stunned to discover that as a young teenager. Now, as a more mature adult I recognise that scientists say this to stun us young teenagers. But the empty space that they say is empty, is not at all empty - it is full of fields!
This also raises for me a separate question. We are apt to think of the electron and the EM field as separate entities. But of course we cannot separate the electron from the field at all. This suggest that ontologically speaking the electron is somehow contiguous to the field.
Another question that I find thought provoking is the characterisation of the atom as something that is uncuttable or undividable. But of course space has this property. Should we think of space itself as some kind of atom? If so, the size of this atom beggars belief! It's as large as the observable universe!
Hi Werner,
Delete"Like letters of the alphabet, [patterns] combine to form words, sentences, tales ..."
Well said! It brought to mind one of the most insightful and astonishingly compact explorations I've ever seen of how the universe enables patterns to build upon patterns: David Christian's TED talk, "The history of the world in 18 minutes".
Christian is a historian, not a physicist, yet he has an uncanny knack for teasing out where the delicate interplay of stability (coolness) and chaos (heat) enables the emergence of an entirely new, unexpected, and inevitably more fragile class of patterns from earlier ones. This new, more complex level of physical reality then becomes the foundation from which still more complex patterns may someday emerge.
-----
You also said: "As we know ... steel is to more than 99.9% empty space! Are you saying that it is not the electrons, but the space-filling wave functions that exert the pressure?"
One of the most pernicious and persistent fictions of introductory physics books is the idea that room temperature atoms are almost entirely space. This comes from the Bohr atom view that electrons are point-like objects that whiz around at incredible speed.
Experimentally, however, the Bohr description is meaningful only if you drench the atom in extremely hard gamma rays. This added energy very briefly shrinks individual electron wave functions until they occupy only 0.1% of the total atomic volume. The atom will of course also be utterly obliterated by the sudden input of energy which is why this mostly-space version of the atom is in no way representative of actual room temperature atoms
For room temperature atoms the electron wave functions (orbitals) are the only meaningful representations of electrons, since there is no more detailed information on electron locations anywhere in the universe. In every way that matters, the electron and its electron orbital in a cold atom are one and the same thing, not two separate entities.
And yes, it is these waves that are very resistant to pressure, precisely because it requires so much more energy to make the electrons smaller and more compact
Thus far from being mostly empty space, a cold atom is filled almost to the brim with big puffy versions of electrons-as-wave-functions that push back hard when squeezed.
@Mozibur, @Terry:
DeleteI understand your arguments -- and I see them as a modern expression of "horror vacui". :-)
The classical world was filled with continuous fluids and solids with average properties like density, velocity, pressure, temperature ... Quantum physics has exposed the graininess that is really present. The utterly naive realist that I am thinks of these grains as real, and of fields as a derived concept: they describe the tendency of "charges" to be accelerated if they happen to get there. And isn't it appealing to have a true synthesis of the wave and particle pictures? Rather than this transcendental talk about "quantum objects" that are neither particles nor waves, but a combination of both? And beyond human understanding? The quantum revolution isn't really completed until the idea of atomism is extended from space to space-time.
The photon from the end of the universe -- is it really the "same" photon that triggers the CCD device, or is it a new photon created through the fantastic choreography of zillions of electrons in the telescope mirror? A photon is not created or absorbed in an instant. The absorption of a photon of visible light is itself a pattern of events separated in time on the order of femtoseconds. And clearly separated in time from the events in the mirror by nanoseconds. I just cannot fit the instantaneous "collapse of the wave function" into this picture. And I know that many physicists loathe theories that are non-local in time. But I cannot think of a realist alternative.
Re “I agree that physics can't end with the pronouncement that the universe "is made of" events. It is the correlations, the patterns formed by these sand grains that are interesting. Like letters of the alphabet, they combine to form words, sentences, tales ...” (Werner 8:21 AM, June 04, 2020 )
Deleteand
“Well said! It brought to mind one of the most insightful and astonishingly compact explorations I've ever seen of how the universe enables patterns to build upon patterns…” (Terry Bollinger 11:44 PM, June 04, 2020) :
What absolute delusional b*llsh*t. Patterns don’t objectively exist: they only exist from a point of view, e.g. a human point of view, and only after the brain processes raw incoming information.
Wheeler: It from bit. Otherwise put, every it — every particle, every field of force, even the space-time continuum itself — derives its function, its meaning, its very existence entirely — even if in some contexts indirectly — from the apparatus-elicited answers to yes-or-no questions, binary choices, bits. It from bit symbolizes the idea that every item of the physical world has at bottom — a very deep bottom, in most instances — an immaterial source and explanation; that which we call reality arises in the last analysis from the posing of yes-no questions and the registering of equipment-evoked responses; in short, that all things physical are information-theoretic in origin and that this is a participatory universe.
DeleteHi Lorraine Ford,
DeleteYou said “What absolute delusional b*llsh*t”.
I think I get your drift, but hey, you need to stop waffling and tell my what you really think!
I was going to sleep in late today, but I made the mistake of reading this early. I started laughing so hard there was no ways I was going to get back to sleep!
Lorraine Ford, you are of course exactly correct.
For example, I challenge anyone to uncover a case in which some miner came out of a mine clutching a newly-found, naturally-occurring copy of the Periodic Table in his hands. The Periodic Table is, after all and to quote Lorraine, “absolute delusional b*llsh*t … [a pattern that exists] only … from a point of view … and only after the brain processes raw incoming information.” The brain in question for the case of the Periodic Tables was owned by Mendeleev, and he did indeed have to process a lot of raw incoming information, over a lot of years, to come up with it.
Ditto and even more so for Kepler! That was one huge and ugly pile of raw data he had to go through, and in his age very few folks even suspected yet that some trivial little b*llsh*t scribble of human-brain created symbols on a piece of paper might actually predict how the planets would move in the future. Totally and 100% human constructed! And so on for Pasteur, Newton, Einstein, and many others. Anyone who thinks there are actual equations, literal scribbles sitting out there somewhere in the cosmos, is engaging in pure fantasy.
If some of your angst was directed in particular at the historian David Christian, I can only guess why. Christian was mostly pointing out through a decent hierarchy argument why it is that human intelligence and society occupy such an incredibly tiny percentage of this enormous universe. Every one of islands of stability that he describes requires some existence of some earlier and more fundamental islands of stability. As a result of this limitation, things start getting pretty slim percentage-wise by the time you get to a solar system and a planet and a set of surface conditions on which folks like us can be having this conversation.
If your angst was instead for my use of the word “patterns”, sure, I absolutely blurred the meaning — but not in an uncommon way — to include both the pattern in some human mind, and the… regularities?… in how the physical world behaves. It was these regularities that made it possible for humans to perceive patterns that were both enduring and predictable. When Mendeleev saw regular patterns in raw data, he not only created his table, but also implicitly made an assertion that is at the very heart of the scientific method, engineering, and modern medicine: That once such a pattern is found, and if it has been found in a precisely specified way, then when other humans follow the same rules, a recognizable similar version of that pattern will be repeated in a way that allow them to predict outcomes in advance.
Thus to most scientists and engineering — and I think also for most regular English uses of the word — pattern has a double meaning: It refers not just to the recognition and assertion we make in our mind, but also to a regularity in the world around us. It is these regularities that enable us to make things that manipulate that world in interesting ways. Thus to chemists, the pattern of alkali metals is more than just a drawing or figure. It’s a statement about a shared predictability of how chemistry works for anyone, anywhere, at any time… and that makes this idea of patterns useful when talking about the physical world.
Hi Prof. David Edwards,
DeleteYou said: “Wheeler: It from bit. Otherwise put, every it — every particle, every field of force, even the space-time continuum itself — derives its function, its meaning, its very existence entirely — even if in some contexts indirectly — from the apparatus-elicited answers to yes-or-no questions, binary choices, bits.”
Fascinating! Stated as you have just stated it, I apparently am far more of a Wheeler it-from-bit type than I had realized. I’ve not read his views very closely due to my disinterest in his “ultimate observer” idea. To paraphrase the title of a superb Niven/Pournelle novel, I have (perhaps incorrectly) always interpreted Wheeler as believing that the universe is the mote in God’s eye.
In sharp contrast, I’ve morphed over to a different view of the observer problem: the mote is God’s eye. That is, I would assert that all an “observer” needs to be is something with a large number of possible states, such as a mote of thermal dust, for its interaction with a quantum wave function to result in part of that wave function becoming statistical irreversible. Thus once the momentum of a single photon is absorbed by a dust mote, phonon interactions within that dust mote quickly make it so statistically complex that the likelihood of the photon ever reforming becomes nil… not just at that moment, but forever after.
Thus a bit has been created, and the universe has moved forward in time into a classical future with fewer options and “a bit” more entropy.
But if that local absorbed photon wave function was also part of an entangled pair — e.g., if the photon was emitted originally by an electron, with which it thus unavoidably remains linear-momentum entangled — then think about it: After the mote-observed photon loses its ability to reverse and change, the still-quantum end of its momentum pair over at the emitting electron will necessarily also collapse into a narrower, more “observed” wave function that provides the classical universe with more information about current state.
You also mentioned the phrase “apparatus-elicited answers”.
I’ve recently move to the view that the definition of a wave function boils down to nothing more than the full set of “superselection” rules. Some of these will reside locally with the test apparatus, but others will be at locations as far away as the other side of the visible universe.
Too extreme? Not really. Everyday our world is bombarded with photons from the edge of the visible universe, and each of these adds its own bit of momentum and energy confusion to our world. Such interactions help the universe look after its own existence by making itself ever more statistically irreversible.
I call wave functions that are defined only by superselection rules dark, since they are defined not by the presence of infinitely many possible universes (MWI, bright), but by absence of enough energy and enough final details to shrink them any smaller. An electron in this view becomes not much more than a superselection cubby hole in which a cluster of absolutely conserved quantum numbers can be compactly stored.
Thus an electron in a hydrogen atom is its orbital wave function — period. It’s not some particle whizzing around in it, because that is an entirely distinct and much more energetic scenario. The proton provides most of the local stabilization, but other superselection rules may come from… well, who knows? Like Sean Carroll and Latham Boyle, I am an advocate of paired universes, ones that in my version of the idea sum up to exactly null. So, speaking of long-distance entanglements, I would assert that the charge of an electron is not maintained by any local superselection rule, but rather by its entanglement with a positron in another universe, a universe whose time and mass-energy are both negative relative to our own.
Now that’s what I would call long-range entanglement!
Lawrence Crowell8:07 AM, May 31, 2020
Delete"The Banach-Tarski Paradox, where the axiom of choice leads to an odd duplication of spheres or that a ball the size of Earth can be decomposes and reassembled into one that would fit into an atom."
But it's talking about R^n, not matter, so it might be misleading to talk about "Earth" and "atom"s.
"The axiom of choice leads to some odd things."
Not in a finite universe, it doesn't. It is the axiom of infinity which causes all the problems, and that axiom is probably not physical.
""As a mathematician I know put it,” Set theory is set on your ass theory.” I can in some ways see this objection to this whole subject. It is an area of math that becomes quickly mired in matters of undecidability, as does the continuum hypothesis, so that we become somewhat lost."
Physics is written in terms of analysis and analysis is written in terms of sets (no-one is going to bother doing a total re-write in terms of infinitesimals or impredicative analysis or what-not). Set Theory gives us a handle on all this - it at least shows that analysis isn't immediately obviously inconsistent.
" As a rule, I do tend to prefer more standard mathematics with algebra, geometry, number theory etc."
But a lot of modern algebra is about sets with operations. In group theory you will very quickly get to questions whose answers will be influenced by set theory. For example, the Whitehead problem is a natural problem in group theory, but it is independent of ZFC. Can your or your Mathematician friend's intuition resolve what ZFC cannot? - I doubt it.
"The complement of a fractal set is undecidable... This invariant set theory of Palmer and Hossenfelder as a means of connecting nonlinearity with QM is interesting."
I think ideas like continuity and undecidability are simply artefacts in a physical brain evolved in a physical world with coarse perception. The hopeful idea in superdeterminism is considering the lack of independence of the detectors and the event. The truth or not of this is not going to depend on subtleties of the continuum which is probably not even real.
Prof. David Edwards6:24 AM, June 06, 2020
Delete"It from bit."
Interesting idea though it is, there's no empirical evidence of it, is there? Bit from it, there is evidence of - a computer.
@ Terry,
DeleteWheeler and my approach to "the all" is pluralistic idealism! This is like Leibniz's monadology without the final monad.
@ Steven,
There is enormous empirical evidence for the quantum mechanical algorithm and quantum theory is best understood as a form of perspectivism not physicalism.
Hi Terry,
DeleteTo be more precise, what I was saying is that your and Werner’s notion that patterns have a type of independent Platonic existence is delusional b*llsh*t. Werner said that patterns “combine to form words, sentences, tales…”; you said “the universe enables patterns to build upon patterns”. You both seem to be saying that patterns are things that have an actual existence.
But the various versions of the periodic table only exist from the point of view of human beings: human beings have discerned patterns, and they have arranged the periodic table accordingly. The periodic table does not represent an actual pattern that independently exists.
What actually genuinely exists is the individual (lawful) relationships and particle interactions that constitute atoms. Any patterns that exist in the world only exist from the point of view of those that can discern patterns, and when it comes to the planets and the periodic table, the patterns that people have discerned are merely a consequence of underlying (lawful) relationships and interactions.
So patterns don’t “build upon patterns”: there is nothing stable about patterns; patterns, fractals and complexity are not structural units or causes; “the universe” doesn’t know about patterns, fractals or complexity; only living things have the ability to discern these patterns.
Terry Bollinger wrote: "... the charge of an electron ... [is maintained] by its entanglement with a positron in another universe, a universe whose time and mass-energy are both negative relative to our own"
DeleteSo you've boiled down MWI to two universes. Nice!
A time running backwards was introduced by Schwinger in 1960, in his "closed time-path" formalism that today is often referred to as Keldysh formalism. Apparently, it still hasn't become very popular - in many simple applications it is found to produce the exact same results as Fermi's Golden Rule. But with forward- and backward-running ("retrocausal") propagators it agrees with Nature's book-keeping. Schwinger introduced it as a purely technical device. However, if you imagine that the events ("sand grains" that we talked about) really always arrive in close pairs (with one event on each time branch) a single universe will do. And you can even envisage a realist description of it.
Hi Lorraine,
DeleteThanks! I think I now have a better understanding of your objections.
Your description of lawful particle interactions reminded me of Richard Feynman’s assertion that apart from atomic nuclei, all the behaviors of the world we see around us could in principle be calculated directly using Feynman’s QED version of field theory. While pragmatic about its use, Feynman nonetheless felt that any calculation that did not start with full quantum field theory was necessarily an approximation, and so could never be entirely accurate.
Thus by using nothing more than the “lawful particle interactions” of QED, there would never be a need to invoke any higher-level groupings or patterns, which would be definition be only approximations created by human perception. In QED even the concept of atoms is an unnecessary addition, since atoms are just incomplete approximations of the more complete QED relationships between positive and negative particles.
But if atoms are not truly fundamental, why are they so darned useful?
The reason, oddly enough, has to do with noise suppression.
About 99.9% of ordinary matter in the universe consists of hot plasmas in which atoms and electrons are only loosely bound to each other. Chemistry largely disappears in such plasmas due to the valence electrons of atoms being stripped away. Thus if Mendeleev had been a creature of plasma and photons he never would have proposed his table, since ionized plasma just doesn’t behave that way.
Heat is form of noise, like shouting so loud that nothing else can be heard. For example, why don’t children build snowpeople out of water? Snow is after all just a form of water, so what is about liquid water that keeps it from expressing complex shapes and sculptures? The difficulty is that in liquid water the thermal motion of the molecules dominates, keeping them from maintaining relative positions to each other. It is not until such molecules are cooled down enough for them to be tightly caged in crystals that the more subtle binding effects of how they interact with each other begin to dominate. At higher temperatures, at noisier temperatures, such binding is obliterated before it even begins.
The molecules of chemistry are much like snowpeople. If enough heat is removed from plasma, electron stripping halts, neutral atoms emerge, and the much weaker, subtler, and more complex binding behaviors of electron orbital chemistry begins to dominate. This weaker form of bonding is not something created only by human perception. It is in fact encoded deep within the foundations of QED. It’s just that in most of the universe such bonding is overwhelmed and thus suppressed by the noise of far more energetic interactions.
So, instead of saying we live in patterns built upon patterns, perhaps I should have said this: We live in silences built upon silences. I’ll even dare to wax poetic again: Our very existence is a whisper from out of the deepest reaches of physics, a voice of complexity that can be heard only within the smallest, most peaceful, and most delicate realms of an otherwise tremendously energetic cosmos.
Lorraine, thank you for your comments. You’ve forced me to think. Good for ol’ noggin, that!
So Terry,
DeleteRe “an electron in a hydrogen atom is its orbital wave function” (Terry Bollinger 2:33 PM, June 06, 2020):
I think what you are saying is that an electron IS a pattern (of probabilities). But I would think that, from the point of view of “the universe”, patterns don’t exist.
This is one of my two biggest wonders about physics (the other one being about the Young's double slit experiment, which we briefly discussed on this very blog a couple years ago), what do we actually measure in the experiments that show Bell's inequality is violated.
ReplyDeleteAnd I'm feeling that this sentence of yours, Sabine, is key here:
"In quantum mechanics, the spin in two orthogonal directions has the same type of mutual uncertainty as the position and momentum."
I can't get an intuition of the fact that orthogonal measurements of the spin would have mutual uncertainty, and would like to ask, how can I learn more about that (as a non-physicist-neither-mathematician-of-trade, but with enough culture of maths and physics to follow through an argument that would involve maths and physics at, say, a bachelor's level)?
Susskind's and co-author's series of books, "Theoretical Minimum"
DeleteMy biggest wonder is how Newton demonstrated that within light there is such a spectrum of pure and intense colours by use of a prism. It's a simple enough experiment that any child can carry it out, but nevertheless, it never ceases to amaze me.
DeleteIt seems quite reasonable that figuring out how to relax the assumption of detector independence in a way that leads to the correlations exactly described by QM, not more, not less, could be a promising area of research. If successful, it would answer the criticism that abandoning statistical independence means anything is possible and that the whole approach is reduced to "the universe conspired to do that".
ReplyDeleteSergei,
DeleteThe conspiracy argument is logically wrong. It assumes what it purports to show. We explained this in our paper, see section 4.2.
Sergei,
DeleteThis "conspiracy" argument originates in a flawed understanding of how logic works. When an argument is put forward, the one who makes the argument has the burden of justifying the premises. In the case of Bell's theorem, the burden is on the supporters of this theorem to show that the independence assumption is true, not on the critics, to show that the assumption is false.
Until one can show that the independence assumption must hold for every classical theory the conclusion of the theorem does not follow, so it is perfectly reasonable to ignore it. Take for example classical electromagnetism. Can you prove that the polarization of an EM wave is independent of the state of a distant detector?
Any time there is interaction between two systems you have correlations. The source and detectors interact both gravitationally and electromagnetically, so correlations between them are to be expected. Can you show that the independence assumption must be true in spite of those correlations?
Andrei wrote:
Delete> Take for example classical electromagnetism. Can you prove that the polarization of an EM wave is independent of the state of a distant detector?
Andrei, you remember our detailed discussion about a similar issue in EM a while back here in Sabine's comments section? You made a very specific claim and I proved mathematically that your claim was wrong, as you conceded.
The general case is, as we say, "intuitively obvious." Now, that general case could be proven in detail mathematically, but anyone capable of understanding that mathematical proof already sees that the result is obvious. So, it would be a waste of any physicist's time to write out the full detailed proof.
The general proof, by the way, would just be generalizing what I proved to you. Quite obvious to anyone who understands the proof I provided to you.
By the way, this is in fact almost universal in mathematics: mathematicians (and of course physicists) almost never bother to write a proof out in all the detail needed for a computer theorem checker to check the proof.
What then should be done with those who cannot understand why the generalization of the proof I gave you is intuitively obvious? They should be encouraged to major in literature rather than STEM!
PhysicistDave5:02 AM, May 31, 2020
DeleteBut, Dave, you think weak emergence of conscious experience is ruled out simply because you can't envisage it. Should you have majored in Literature?
PhysicistDave,
Delete"Andrei, you remember our detailed discussion about a similar issue in EM a while back here in Sabine's comments section? You made a very specific claim and I proved mathematically that your claim was wrong, as you conceded."
Correct. My claim was that for any subsystems in our iniverse, A and B, described by classical EM it is not possible to imagine a counterfactual universe where A'=A yet B'≠B (A' and B' being part of that counterfactual universe). That claim was wrong.
Nevertheless, your examples employed source-free fields. Yes, they are allowed by classical EM but they are useless when discussing real Bell tests because, obviously, you cannot make such fields pop out of nothing. In reality, all fields we can employ in a Bell test are produced by charges, and the fields at B produced by the charges at A are not independent of those charges. So, in this situation, the independence assumption fails.
A different situation where the independence assumption may hold is for continuous distribution of charges. A uniformly charged sphere has the same electric field as a charge positioned at the center of the sphere. But this case is also irrelevant because in reality charge is quantized, so there is no such thing as a uniformly charged sphere.
So, in the end, for real-life situations there is no justification for the independence assumption.
"The general case is, as we say, "intuitively obvious."
On the contrary, in the general case of interacting systems one expects the systems to be correlated. The existence of atoms, large objects like chairs and tables or planetary systems or galaxies is based on the fact that distant subsystems do not move randomly. If they would, the universe would only contain a uniform distribution of particles.
"Now, that general case could be proven in detail mathematically, but anyone capable of understanding that mathematical proof already sees that the result is obvious"
I doubt. Such a proof would conflict with the observed fact that there exist distant systems that are correlated, such as those mentioned above. When you look towards a mountain you expect to see the mountain, not random noise. Hence, the EM fields at your location are not independent on the charge distribution of the mountain.
"The general proof, by the way, would just be generalizing what I proved to you. Quite obvious to anyone who understands the proof I provided to you."
Your proof was based on source-free fields. It does not work if we limit to fields associated with charges and if we take into account that charge is quantized.
Andrei,
DeleteIf you look back, I think I explained to you at the time that you are also wrong on the issue of sourceless fields, but the math required happens to be math that you yourself said you cannot grasp: Green's functions, Fourier analysis, etc.
Not much that I can do about that. The fact that you turned out to be wrong on the issue that required math you can grasp and on which you were so sure you were right should perhaps indicate to you that I understand all this much, much better than you.
This perhaps is why you should hire physicists to do physics, just as we physicists hire medical doctors to do medicine.
But if you wish to continue believing something false because you do not know and will not learn the relevant math... well, that is not my fault.
As to the issue of quantized charges, there is no generally accepted theory of quantized charges in classical physics. If you allow the quantized charge to be distributed in space, then by special relativity it gets distorted when you try to accelerate it -- which means you are dealing with charge distributions again.
And point charges in classical physics have pathologies that are very severe: there is no consensus on how to handle them (never will be, in my opinion).
So, neither I nor you nor anyone can deal sensibly with your issues with classical quantized charges -- what you are talking about is meaningless. Sorry 'bout that.
You are forgetting what I long ago explained.
By the way, for the record, I am of course assuming classical gravity to be GR: the results there are also intuitively obvious, but way beyond you mathematically.
The rest of what you wrote is nonsense. For example, you wrote:
> Such a proof would conflict with the observed fact that there exist distant systems that are correlated, such as those mentioned above. When you look towards a mountain you expect to see the mountain, not random noise.
What I am claiming and what I proved is that such correlations are not required in classical physics and cannot be proven to exist in classical physics. Of course, if things interacted in the past, came from a common source, etc., there might be correlations: that is not ruled out by anything I have said nor is it a violation of Bell's theorem.
Fundamentally, you continue to misunderstand what Bell's theorem states. It most emphatically does not state that there are no correlations between separated systems! Very, very strong correlations between separated systems are consistent with Bell's theorem and are commonly the case.
You have bizarrely false intuitions about lots of things based on the fact that you have a superficial, verbal understanding of various things in physics without actually understanding the physics mathematically. That does not work.
Your problem all along has been that you have never gone to the trouble to understand Bell's theorem. The whole point of the theorem is the detailed mathematical statement it makes. All of the attempts to summarize it in terms of some vague verbal statement such as "There can be no correlations between distant systems" are simply, ludicrously wrong.
Dave
PhysicistDave,
Delete“Fundamentally, you continue to misunderstand what Bell's theorem states. It most emphatically does not state that there are no correlations between separated systems!”
Let’s see:
From Sabine’s paper - Rethinking Superdeterminism, page 5:
Violation of Statistical Independence: “the probability distribution of the hidden variables, ρ(λ), is not independent of the detector settings.”
So, in order for the conclusion of Bell’s theorem to follow you need to show that in the case of a Bell test, as described by classical EM, “the probability distribution of the hidden variables” (the hidden variables being the polarization of the EM waves originating at the source) is independent of the detector settings.
The detector settings are represented by the orientation of the polarizers, which is nothing else but the distribution of the charged particles (electrons and nuclei) that make up those polarizers. Hopefully, you agree with that.
The hidden variables, (the polarization of the entangled photons/EM waves) would be a function of the EM fields acting at the location of the source, the fields that accelerate the charges (electrons).
So, in conclusion, Bell’s theorem requires that the charge distribution at the detectors’ location and the EM fields at the location of the source must be uncorrelated (statistically independent). If you disagree, please explain why you disagree and provide the correct approach.
I will reply to your other points after we establish a common ground and agree on what Statistical Independence means in the context of EM.
Andrei wrote to me:
Delete>The detector settings are represented by the orientation of the polarizers, which is nothing else but the distribution of the charged particles (electrons and nuclei) that make up those polarizers. Hopefully, you agree with that.
No, I don't.
You just will not listen to what I say, or, to be more fair, you cannot believe it because, as you yourself admitted, you lack the requisite math.
You wanted to assume a classical world based solely on Maxwell-Lorentz EM. But, as I keep saying, there can be no atoms in classical EM. There can be no discrete quantized charges in classical EM. Maxwell's equations relate to charge distributions and current distributions, and when you try to tie these down to point charges you get contradictions that appear insuperable.
When I have tried to point this out to you in the past, your only coherent response was to appeal to "stochastic electrodynamics."
So, because you kept bringing it up, I went to the trouble to get The Quantum Dice: An Introduction to Stochastic Electrodynamics by Luis de la Peña and A.M. Cetto out of the library.
I started writing down all the cases in which the authors said, in so many words, of course this does not work and that does not work but maybe someday someone will work this all out. I finally just gave up, because that was pretty much what the book was: a detailed confession that SED is nonsense.
Now, of course, someone actually did take classical EM and make a bunch of modifications so that it agrees with experiment. The resulting theory is generally known as... quantum mechanics.
Any competent physicist could tell you that SED is doomed to be a bizarre and dismal failure, as it surely is. But you have kept appealing to that in the dismal hope that somehow that will allow you to do what you want.
It doesn't. No one has ever created what you want and no one ever will because it is mathematically impossible. But you cannot understand the proof because, as you admitted, you lack the requisite math to understand the initial value problems for differential equations.
There are no photons in classical EM. Since there are no photons, there is no polarization for a photon in classical EM. Atoms collapse almost instantaneously in classical EM, which is just as well since there are no electrons in classical EM. There are no molecules, no polarizers, no whatever you want in pure Maxwell-Lorentz EM.
So, how on earth can we teach classical EM? We assume, as Lorentz did, that there must be other forces present, ultimately forces described by quantum mechanics. But your whole plan was for everything to work with classical Maxwell-Lorentz EM alone, so you do not have that option.
There are so many reasons that what you want will not work that you are just being foolish to push it.
In the thread that I linked to, I pinned you down to one point that you said you would live or die on, and I proved, to your satisfaction, that you were indeed wrong on that point.
But of course, you are not willing to actually have your ideas subjected to a live-or-die test: you still keep pushing them.
Not science.
I played the game by the rules you yourself set up on an issue that you claimed was the key issue.
You lost.
I will keep pointing out why you are wrong, but I am not going to tolerate you repeatedly moving the goalposts and jerking me around.
Andrei also wrote:
>I will reply to your other points after we establish a common ground and agree on what Statistical Independence means in the context of EM.
Nope. Not gonna happen. I played the game by your rules and you lost, fair and square
I indulged your silliness once; not again. I have explained in multiple ways that any competent scientist can understand why you are selling utter nonsense.
I'm not playing a new game by your new rules.
No do-over.
Dave
Steven Evans wrote to me:
Delete>But, Dave, you think weak emergence of conscious experience is ruled out simply because you can't envisage it. Should you have majored in Literature?
Do you understand the idea of a “non sequitor,” Steve?
Andrei keeps making mathematical claims that can be proven to be wrong via deductive logic.
I convinced him of that in one case; in another case, the one he was discussing here, he admitted that he could not follow the math involved.
You are in the same boat as Andrei.
You keep thinking you have proved certain things about consciousness, God, and all the other things you are so obsessed with, when you are woefully ignorant of the concept of “proof.”
For example, you keep insisting that because no one has ever detected a disembodied consciousness, that this fact proves that such a thing does not exist.
That is the well-known “black swan” fallacy: the fact that until recent times no European had seen a black swan did not prove that such a swan did not exist.
The failure to detect a disembodied consciousness is of course suggestive evidence that such a thing does not exist, but it is not proof.
I have proven that certain arguments for consciousness arising via weak emergence fail: specifically, the claim that computer logic circuits exhibit meaning. I have also shown via simple arguments in metalogic that there is a “semantic gap” in trying to derive consciousness from physics as it now exists in the same way that there is a semantic gap in trying to derive an “ought” from an “is” (Hume's argument). To be sure, hundreds of philosophers have tried to prove Hume wrong, but they have all failed: the metalogical proof is very straightforward math and cannot be, and never will be, refuted, any more than the quadratic formula will ever be refuted.
It is not what I can “envisage” but what I can prove about certain arguments for deriving consciousness from physics. These proofs are not, to be sure, as widely known as the proofs of Andrei's errors, but they are mathematical proofs, nonetheless.
Does that mean that I claim, as you say, to know that consciousness cannot arise via “weak emergence”? Well, I have said, again and again, that, for all I know, consciousness might be explained via physics alone plus a “translation dictionary” that indicates which physical states correspond to which experiential states. I suspect that some people would label that as “weak emergence”; some would not.
But you don't get any of this, because you do not know much mathematical logic, just as Andrei cannot see why he is wrong, because he knows next to nothing about the initial value problem for differential equations.
I get that: no one knows everything – I myself am woefully ignorant about gourmet cooking, car repair, gardening, poker, and many other topics.
But why are you and Andrei so incredibly dogmatic on topics about which you guys are so incredibly ignorant? I bet you are both less dogmatic about any subject in which you have real expertise (you do have real expertise in some subject, don't you?).
Why don't you bother to acquire some basic knowledge of logic before you pontificate in the subject?
PhysicistDave,
Delete“You wanted to assume a classical world based solely on Maxwell-Lorentz EM. But, as I keep saying, there can be no atoms in classical EM. There can be no discrete quantized charges in classical EM. Maxwell's equations relate to charge distributions and current distributions, and when you try to tie these down to point charges you get contradictions that appear insuperable.”
“Atoms collapse almost instantaneously in classical EM, which is just as well since there are no electrons in classical EM. There are no molecules, no polarizers, no whatever you want in pure Maxwell-Lorentz EM.”
“There are no photons in classical EM. Since there are no photons, there is no polarization for a photon in classical EM.”
OK, let’s then focus on how justified the above statements are and how relevant are they for my argument, that classical EM cannot be ruled out by Bell.
A. The problem of quantized charges.
1. True, the Maxwell-Lorentz EM does not give a mathematically consistent description of quantized charges. However, solutions are known to exist. For example, the Born–Infeld theory of electromagnetism (which has been investigated in recent times due to some links with string theory) can deal with quantized charges. So unless you can point out to a rigorous mathematical proof that quantized charges cannot be accounted for in a classical theory your assertion remains unjustified. The words “appear insuperable” seems to suggest that you know of no such rigorous proof.
2. My argument does not require one to have a fundamental understanding of the nature of the electron. We know that electrons exist, we know they are charged, we know they can be accelerated with EM fields, we know that they radiate when accelerated, and so on. For the purpose of this discussion we may assume that the electrons are point charges. But if the problem of quantized charges bothers you so much you can reformulate your argument in the context of the Born–Infeld theory.
B. The problem of the stability of the atoms.
It is true that a particular classical model of the atom fails. This does not prove that no such model can succeed. SED is currently investigating the model of an atom where the zero-point field compensates for the energy loss due to radiation. Regardless, unless you can provide a rigorous proof that classical atoms cannot exist you have no grounds to assert it. It is an open problem that can be and should be investigated separately from Bell’s independence assumption.
C. There are no photons in classical EM.
True, there are EM waves, and those waves have a polarization.
“In the thread that I linked to, I pinned you down to one point that you said you would live or die on, and I proved, to your satisfaction, that you were indeed wrong on that point.”
It is not my fault that the examples you provided have no connection whatsoever with the conditions involved in real Bell tests. So while I accepted defeat for that particular argument I can still hold on my original argument, that takes into account that electrons exist, charge is quantized and the fields involved have sources. Your examples lack the required generality to cover real-world scenarios.
“I will keep pointing out why you are wrong, but I am not going to tolerate you repeatedly moving the goalposts and jerking me around.”
They are different arguments. You will never see me reviving the argument that I lost, that does not mean that I cannot formulate a different one.
“I indulged your silliness once; not again. I have explained in multiple ways that any competent scientist can understand why you are selling utter nonsense.”
Yeah, right! You just cannot tell if in classical EM the field of a charge is not independent of that charge because the internal structure of the electron has not been elucidated. Just cut the BS, Dave. You know very well that the fields at the location of the source, originating at the detector, cannot be independent of the position of the detector, and this trivial fact gives your beloved Bell theorem a much-deserved proper burial.
@PhysicistDave:
DeleteActually the most important philosopher to take on Humes description of conscionness as merely the play of sensation and causality as merely convention is Kant.
According to Kants own admission reading Hume awoke him from his 'dogmatic slumber' and motivated him to find out just how consciousness can be said to exist. The long and short of it is that he created the notion of the transcendental ego, its basically a form of idealism where he takes Platos forms in the realm of ideas into the mind of man. Platos forms, in Kants hands help shape how consciousness apprehend a and understands the world. It is that which orders the manifold of sense perception in such a way that it makes sense to us - this is the unity of apperception or consciousness. This is the I when we say I.
Just as importantly he distinguished between synthetic and analytic truths, saying that space and time were synthetic a priori truths. That is, space and time are the foundations of our experience. They are there, in order for us to have experience.
Many analytic philosophers, after the Einstein supposed his use of non-Euclidean geometry falsified Kantian philosophy. This is to misunderstand how Kant understood geometry. We, after all, can never directly experience such geometries. A strong enough gravitational field that would appreciably change our local Euclidean geometry would simply kill us. Biological life cannot be supported in such an environment. Thus, Kant can safely say that our experience of Euclidean geometry, is 'apodectic'. That is immediately certain and without question. This has been seriously misunderstood as suggesting that Kant supposed that non-Euclidean geometry was not possible.
In fact, Kants theorising of the distinction between analytic and synthetic truths suggested to him that a geometric truth such as the angles of a triangle must add up to 180 degrees was in some way conventional, that is, it could have been otherwise.
This is important, since its known that Gauss read Kants Critique of Pure Reason where this argument was made at least five times. Thus, it may have been possible that Kant was indirectly responsible for the discovery of non-Euclidean geometry by Gauss.
For a man of Gauss's mathematical aptitude and genius, a hint of such a possibility would have been more than enough for him to formulate how it indeed this was possible.
This would be ironic, since as I have already alluded to above, it was Reichenbach's suggestion that Einstein's use of non-Euclidean geometry in GR that invalidated Kants critique!
Andrei wrote to me:
Delete>True, the Maxwell-Lorentz EM does not give a mathematically consistent description of quantized charges. However, solutions are known to exist. For example, the Born–Infeld theory of electromagnetism (which has been investigated in recent times due to some links with string theory) can deal with quantized charges.
Indeed. If you think you can make Born-Infeld theory reproduce the results of quantum mechanics, then, in all seriousness, I urge you to spend the next decade of your life working on that.
You will fail. I would risk my life that you will fail.
But it is not my job to prevent you from wasting the next decade of your life.
Just do it. Why should you care that I am utterly certain that you will fail?
You, and a lot of other vendors of crack-pot ideas who come to Sabine's blog, seem to think that I or Sabine or JeanTate or Lawrence have some obligation to prove, to your satisfaction, that your ideas will not work.
We do not have that obligation. No one is paying us to do that. That is not our job.
We are entitled to explain why you will fail, and if you find our explanations unconvincing... well, tough.
Prove us wrong. Spend the rest of your life trying to make your crack-pot ideas work.
Why should any of us care?
Andrei also wrote:
>It is true that a particular classical model of the atom fails. This does not prove that no such model can succeed. SED is currently investigating the model of an atom where the zero-point field compensates for the energy loss due to radiation.
And they have been “currently investigating” such “models” for many decades, probably since before you were born. And they failed then. And they are still failing now. And they will continue to fail when everyone reading this is long dead. And physicists know why.
But you don't.
Fine – believe in leprechauns if you wish. That does not make them real.
Andre also wrote:
>Regardless, unless you can provide a rigorous proof that classical atoms cannot exist you have no grounds to assert it. It is an open problem that can be and should be investigated separately from Bell’s independence assumption.
The proof is trivial to anyone who understands classical EM and well-known to all competent physicists.
But not to you.
And that is not my problem.
Andrei also wrote:
>[Dave] C. There are no photons in classical EM.
>[Andrei\ True, there are EM waves, and those waves have a polarization.
And that admission on your part is an admission that your project will fail.
Bell's theorem works with individual (pairs of) photons.
When you do not have individual photons, as you do not in classical EM, there is no Bell's experiment.
For any rational person, that ends the debate.
(cont.)
(cont.)
DeleteAndrei also wrote:
>You just cannot tell if in classical EM the field of a charge is not independent of that charge because the internal structure of the electron has not been elucidated. Just cut the BS, Dave. You know very well that the fields at the location of the source, originating at the detector, cannot be independent of the position of the detector, and this trivial fact gives your beloved Bell theorem a much-deserved proper burial.
Nope, I do not know that at all. I do not think my “beloved Bell theorem” has received “a much-deserved proper burial” and I know of no competent physicist, indeed not even any intelligent layman, who thinks that either.
But I have no intention of any longer explaining it to you. I may continue to point our your errors for the benefit of laypersons who wander by.
But, I am coming really to like the idea that you will spend the rest of your life on a wild goose chase.
Y'know, Andrei, if a doctor told you that you will die of lung cancer if you smoke tobacco or an auto mechanic told you that, unless you replace your brake shoes, your brakes will fail and you will die, I kinda doubt that you would demand that they prove this to you, beyond any possible doubt, to your satisfaction. I am almost certain that you would not argue with them interminably for months with one crackpot theory after another as to why tobacco does not cause lung cancer or failed brakes won't get you killed.
But for some reason guys like you who come to Sabine's website do this to physicists.
Most of the actual scientists here have the wisdom not to feed the trolls. I, alas, take my fellow human beings seriously enough, showing respect even to the trolls, that I often try to take seriously what trolls like you say.
Silly me.
But, again, a professional – whether a medical doctor, an auto mechanic, or a physicist – is not obligated to reply to crackpots interminably to convince the crackpots to give up their ideas.
If a substantial number of physicists shared your and the SED folks' goofy idea that classical EM can reproduce the results of QM, I might feel I needed to write a review paper or even a book on the subject.
But that is not the case. You guys are a very small group of misguided people.
I have given enough information – indeed, more than enough – for any competent physicist and indeed any intelligent layman to understand why what you are saying is nonsense.
But, no one will ever convince you.
So, please, I beg you, take your own ideas seriously. Quit your job and devote the next decade of your life to pursuing these ideas.
Show you mean it, Andrei!
PhysicistDave
Delete“ If you think you can make Born-Infeld theory reproduce the results of quantum mechanics…”
Can you please reply to what I said and not to what your rich and colorful imagination makes you think I said? I did not claim that B-I theory reproduces QM. It was a counterexample to your claim that quantized charges cannot exist in classical EM.
“You, and a lot of other vendors of crack-pot ideas who come to Sabine's blog, seem to think that I or Sabine or JeanTate or Lawrence have some obligation to prove, to your satisfaction, that your ideas will not work.”
Your limited understanding of how logic works and what it means for an argument to be sound is staggering! If you assert something it’s not my burden to disprove it, it’s yours to prove it. You say quantized charges cannot exist in classical EM? Fine, prove it! In fact it wasn’t my job to look for B-I theory, that should have been your job. So, if you want me or Sabine or anyone on this forum to take your argument seriously you should prove your claims, not waiting for others to disprove them. Of course, you are not under any obligation to do it, but if you don’t do it you should expect to be ignored.
OK, so, no proof that quantized charges cannot exist in classical EM. Assertion ignored, let’s move forward.
“Prove us wrong.”
This is pure gold! Exactly what I was saying. This logical fallacy is known as “Shifting the burden of proof”.
“The proof is trivial to anyone who understands classical EM and well-known to all competent physicists.”
Asserting that a proof exists cannot replace the proof itself. The proof you are probably thinking about has a lot of assumptions that can be challenged. But, until you present it, it can be safely ignored.
“Bell's theorem works with individual (pairs of) photons.
When you do not have individual photons, as you do not in classical EM, there is no Bell's experiment.”
What you actually detect is not “individual photons”, no one has ever seen such a photon, it’s just detector clicks. Alternative explanations have been proposed, but I think it’s fair to let you substantiate this claim.
So, we still have a bunch of assertions (quantized charges, atomic stability, individual photons) that may or may not be true, so classical EM may or may not fail. Your strategy seems to be to discuss anything else BUT Bell’s independence assumption so that you do not need to face the trivial fact that fields in one region are not independent on their sources. As I said before, one can discuss the independence assumption without understanding the nature of the electron or what the electron does inside an atom. The relevant question is if the (unknown) state of the electron prior to emission can be changed when the EM fields at its location change, and if those fields are or not independent on their distant sources. That’s it! But, good luck with your approach!
Mozibur wrote to me:
Delete>Actually the most important philosopher to take on Humes description of conscionness as merely the play of sensation and causality as merely convention is Kant.
Mozibur, I was not talking about Hume's description of consciousness: I was talking about his claim that you cannot derive an “ought” from an “is.” I merely pointed out that the same argument shows you cannot derive experience from physics: there is, in logical terms, a “semantic gap.”
Kant certainly did not refute Hume's argument that you cannot derive an “ought” from an “is,” as it is a simple theorem in logic, and I do not think Kant ever attempted to refute it. Indeed, Kant attempted to show the Categorical Imperative to be a priori. (Alas, there are quite a few human beings who seem not to find it necessary at all!)
So, everything you wrote is simply not relevant to the point I was making.
The theorem in logic that I mentioned happens to have been made famous by Hume, which is why I mentioned him. However, it was, I assume, probably known long before Hume: indeed, I would guess that even Aristotle would have treated it as obvious.
Hume's point that you cannot derive an “ought” from an “is” is not dependent on the rest of Hume's empiricist philosophy, nor is Hume's argument affected by Kant's “transcendental idealism.”
In any case, as I assume you know, Kant declared in the Preface to the second edition of his Critique of Pure Reason, ““I have therefore found it necessary to deny knowledge, in order to make room for faith.” (In German, “Ich mußte also das Wissen aufheben, um zum Glauben Platz zu bekommen...”) Perhaps it will therefore not surprise you that few scientists today find Kant's philosophy to be particularly enlightening.
I do think your view of Kantian idealism is eccentric: I think General Relativity does prove conclusively that Kant was wrong.
You wrote:
>Thus, Kant can safely say that our experience of Euclidean geometry, is 'apodectic'. That is immediately certain and without question.
Not for me! I have not believed in Euclidean geometry for half a century as anything more than an approximation. In fact, whenever I make actual measurements on the world, for some reason, I never am able to exactly confirm Euclidean geometry!
Nope: I see the world as non-Euclidean. If you don't, that is a shortcoming on your part.
In any case, none of this has anything to do with the point I was making, which is a simple theorem in logic.
Andrei wrote to me:
Delete>Can you please reply to what I said and not to what your rich and colorful imagination makes you think I said?
Nope. Why on earth would I want to do that???
Look – I am trying to be polite, but I really am extremely irritated with you: you led me to believe that if I could disprove your very specific claim about classical EM then you would agree that your general claim was wrong.
You did agree that I disproved your specific claim, but you keep spouting the same general claim as before.
It took me a lot of effort to figure out how to use math that you could understand to prove your specific claim was wrong. I wasted my effort: it turned out that this has not changed your opinion at all.
I do not intend to be manipulated by you twice.
Andrei also wrote to me:
>Your limited understanding of how logic works and what it means for an argument to be sound is staggering! If you assert something it’s not my burden to disprove it, it’s yours to prove it.
Nope.
I have never had the slightest intention of “arguing” with you as you conceive it.
I am a professional who knows things you do not know. Sometimes, out of the goodness of our heart, scientists such as myself, Sabine, JeanTate, et al. choose to mention things about science that we know to be true on public forums such as this.
The idea that therefore we somehow have some “burden of proof” to justify the information that we provide to every Tom, Dick, and Harry who wanders by is just goofy
This is not a debate between you and me in which I have some “burden of proof.”
If I feel like it, I will tell you something I know that you don't know.
I have no obligation at all to prove that I am right to your satisfaction.
Andrei also wrote:
>So, if you want me or Sabine or anyone on this forum to take your argument seriously you should prove your claims, not waiting for others to disprove them. Of course, you are not under any obligation to do it, but if you don’t do it you should expect to be ignored.
I honestly could not care less if you ignore me. And Sabine already knows this stuff: I am not trying to convince or impress her.
Look: you have repeatedly appealed to the pseudo-science known as “stochastic electrodynamics.” If you read through some of this cult's material, as I have, you see that they never quite come out and admit that their silly “theory” has been refuted by observations. Instead, they use words like “difficulty,” “issue,” “problem,” “discrepancy,” “disagreement,” etc.
Yeah, the difficulty/issue/problem/discrepancy/disagreement is that their goofy “theory” was decisively proven to be false decades ago! Any honest scientist would say, “Well, that theory is wrong, better move on.”
But they don't and you won't. Arguing with you about such nonsense makes as much sense as arguing about whether leprechauns really have a pot of gold at the end of the rainbow.
SED is known to be false. Its proponents almost admit that with their weasel wording, but they will not quite come out openly and tell the truth.
Andrei also wrote:
>So, we still have a bunch of assertions (quantized charges, atomic stability, individual photons)...
Now you are starting to get it! I do not intend to prove anything more for your benefit. Ever. At all. You got your one free proof, which you (falsely) led me to believe would suffice.
I will give you no more proofs.
Ever.
I promise.
At least not unless you pay me for my services (and I charge far more than you can afford to pay). I am not your servant.
Where on earth did you get this bizarre idea that if a professional on the Web informs you that you are misinformed in their area of expertise that the professional owes you the service – for free!! – of proving to you that the professional is right??
Really, really weird.
Do you expect free service of this sort from physicians, auto mechanics, lawyers, plumbers, etc.? Do you get it?
@Andrei
DeleteI could locate a nice paper for you on arxiv , from Hanson et al, 2015 : https://arxiv.org/pdf/1508.05949.pdf
"Experimental loophole-free violation of a Bell inequality using entangled electron spins separated by 1.3 km"
Please take especially notice of the phrase: " The
event ready signal lies outside the future light-cone (coloured regions) of the random basis choice of A and B ..."
Thank You.
PhysicistDave3:48 AM, June 07, 2020
Delete"Where on earth did you get this bizarre idea that if a professional on the Web informs you that you are misinformed in their area of expertise that the professional owes you the service – for free!!"
Dave,
*As far as we know* the universe consists only of Standard Model matter + GR space-time ( + maybe dark matter, dark energy).
*As far as we know* every natural phenomenon is weakly emergent from this physics.
And so, *as far as we know* conscious experience is also weakly emergent from this physics.
But you claim that conscious experience can't be weakly emergent from current physics.
Yet, you have provided no reason for this claim - claiming you personally can't see how conscious experience can be weakly emergent, as you have done repeatedly, is not a reason.
So are you now saying I need to pay you to provide a reason because you are a professional?
Sixte,
DeleteLet me first present my complete argument here. It is an exact copy from the thread "The path we didn't take":
1. The polarization of an EM wave depends on the specific way the electron accelerates.
2. The only way an electron can accelerate is Lorentz force.
3. The Lorentz force is given by the electric and magnetic field configuration at the locus of the emission.
4. The electric and magnetic field configuration at the locus of the emission does depend on the position/momenta of distant charges.
5. The detectors are composed of charged particles (electrons and quarks).
Conclusion: From 1-5 it follows that the hidden variable, λ, depends on the detectors’ states." Here, λ is the polarization.
Now, you may say that the state of the source depends on the past state of the detector, not on the state of the detector at the time of detection. True, but the theory is deterministic, so the state of the detector at the time of detection does also depend on the past state of the detector. So, in the end, we arrive at the conclusion that the state of the source at the time of emission is not independent on the state of the detector at the time of detection. This is the reason the paper you linked does not represent a valid rebuttal of the above argument.
The above argument does not prove that Bell’s statistical independence assumption is false in classical EM. It is possible that, in the statistical limit, the independence assumption survives. It’s just that we do not know. And you cannot rule out a theory because of a suspicion that it cannot pass a test. It has to be proven that it cannot pass a test. No such proof has been presented, so, at this time, classical electromagnetism cannot be shown to fail a Bell test.
PhysicistDave,
Delete"I am trying to be polite, but I really am extremely irritated with you: you led me to believe that if I could disprove your very specific claim about classical EM then you would agree that your general claim was wrong."
Your irritation is not justified. My original argument from the thread “The path we didn’t take” was:
"1. The polarization of an EM wave depends on the specific way the electron accelerates.
2. The only way an electron can accelerate is Lorentz force.
3. The Lorentz force is given by the electric and magnetic field configuration at the locus of the emission.
4. The electric and magnetic field configuration at the locus of the emission does depend on the position/momenta of distant charges.
5. The detectors are composed of charged particles (electrons and quarks).
Conclusion: From 1-5 it follows that the hidden variable, λ, depends on the detectors’ states."
Your examples either did not involve any charges (1) or involved charges that occupy the same position (2). The above argument is based on the fact that electrons and quarks exist and those do not occupy the same position. So, your examples cannot possibly refute the above argument. If electrons and quarks would occupy the same position there will be no EM fields associated with neutral objects and my argument would fail. But, in the real world this is not the case.
“I have no obligation at all to prove that I am right to your satisfaction.”
True, and I am perfectly satisfied with this. My argument above stands unrefuted while the professional physicist Dave burns his time with useless rants and irrelevant ad-hominems.
“Where on earth did you get this bizarre idea that if a professional on the Web informs you that you are misinformed in their area of expertise that the professional owes you the service – for free!!”
Your rich and colorful imagination is back again. I have simply informed you (this time for free) that your arguments (and I am very kind to even call them arguments) are unsound. Why on Earth should I pay you to make them sound? I could not care less about them.
Steven Evans wrote to me:
Delete>Dave,
>*As far as we know* the universe consists only of Standard Model matter + GR space-time ( + maybe dark matter, dark energy).
>*As far as we know* every natural phenomenon is weakly emergent from this physics.
>And so, *as far as we know* conscious experience is also weakly emergent from this physics.
You forgot, *as far as we know* conscious experience is NOT weakly emergent from this physics.
You are using a fallacious argument from ignorance: because no one knows something does not show that it is not true.
No one knows how consciousness works.
Steve also wrote:
>But you claim that conscious experience can't be weakly emergent from current physics.
Did I? I have tried to emphasize that the idea of “weak emergence” is a bit fuzzy around the edges, and that my suggestion of the possibility of physics plus a “translation dictionary” might be seen by some people as “weak emergence.” If it turns out to be true (who knows?), I am pretty certain that you will argue that it is “weak emergence”!
Steve also wrote:
>So are you now saying I need to pay you to provide a reason because you are a professional?
Nah: you see I like you better than I like Andrei!
Seriously, Andrei has been spouting nonsense that all competent physicists know to be false. While you and I disagree, lots of bright people think you are right, lots think I am right. Your and my debate is interesting.
Leaving aside “weak emergence,” I have explained, again and again, that “Hume's theorem,” a simple theorem in logic which famously proves that you cannot derive an “ought” from an “is” also proves that you cannot derive propositions relating to experience from physics.
You have never indicated that you understand Hume's theorem, and perhaps that is the problem here.
By the way, a funny example of the same kind of fallacious reasoning from ignorance that you employ occurred with a friend of mine, named Martin, forty years ago:
Martin and I had similar political views, but Martin claimed he could “prove” those views to be true. I claimed it was impossible to prove political positions because of Hume's theorem.
Here is Martin's “proof”:
Martin asked me if I could prove any of the countless political views that were alternative views to his views to be true. I admitted I could not. Martin then triumphantly announced that this proved that his views were true, since none of the alternative views could be proven to be true.
We spent an hour or more going around in circles, with my trying to convince Martin that conceivably all possible answers might be unprovable: this of course is rigorously proven by Gödel's theorem, but Martin, like you, is not real strong in logic.
Do you see that this is almost exactly the same as your and my current discussion? In both cases, a theorem in logic, Hume's theorem (also known as “Hume's law” or “Hume's guillotine”) , proves a certain line of reasoning is impossible. And in both cases, someone – you or Martin – nonetheless uses an argument form ignorance to try to prove his own (provably unprovable) conclusion.
The only difference is that because you don't know of anything beyond physics, you take that to be proof that there is nothing but physics. In Martin's case, because neither he nor I knew of any proof of any political views beyond his own, he took that as proof that his views had been proven to be correct.
Neither of you want to leave room for human ignorance.
I do.
In any case, you are not really arguing with me but with David Hume and, of course, countless logicians who would view Hume's theorem as obviously true.
It would be nice if you would stop saying I have not presented to you a proof, since this is at least the third time I have done so (remember our LiveChat the other day?). If you dispute Hume's theorem, why not explain why, instead of just saying that I have not presented it?
PhysicistDave6:16 AM, June 09, 2020
Delete"You forgot, *as far as we know* conscious experience is NOT weakly emergent from this physics. "
OK, Dave, you make a fair logical point. But still empirically we only know of the Standard Model and GR, we've only ever observed weak emergence, and almost all of the structures that have appeared in evolution are explained by weak emergence. It seems strange that at a particular point in this path, non-weak emergence suddenly appears. But, OK, I see your logically based doubt, even if I am suspicious empirically.
PhysicistDave6:16 AM, June 09, 2020
DeleteDave, let's just get this one point sorted then I'll stop filling up Dr. H.'s combox.
"No one knows how consciousness works."
It's undeniable that there is no current theory of conscious experience. But there is of course observed brain activity which has correlations with reported conscious experience.
"I have tried to emphasize that the idea of “weak emergence” is a bit fuzzy around the edges,"
A weakly emergent explanation of conscious experience would explain completely in terms of the physical brain conscious experience. If there is any translation dictionary structure this would also be explained completely in terms of a physical brain.
"Seriously, Andrei has been spouting nonsense that all competent physicists know to be false."
It is clear you are a competent physicist. That's just a fact.
" you cannot derive an “ought” from an “is” ... You have never indicated that you understand Hume's theorem, "
Fair point. And I thought you weren't paying attention. I understand you to mean here that we can't describe subjective experience in terms of objective scientific observations. Obviously, I don't have handy an objective explanation. But I consider current Physics to be exhaustive up to the current precision of observation. If a more precise empirical theory of matter than the Standard Model appeared it would make no difference to neuroscience. Further, brain activity correlating to some extent to reported conscious experience has already been observed, so I would expect that this brain activity will be observed in more and more detail and more overlap will be found between this and reported conscious experience until it is seen objectively to be conscious experience. I don't view this as a Physics question. Physics has observed what substrate is there to enough precision already to satisfy the needs of chemists and biologists. Also, after several hundred million years of evolution the fact that a complex material brain is capable of conscious experience suggests the structure of the brain is the explanation not some new physics, and sure enough a little progress has been made by neuroscientists, and zero progress by non-materialists.
"Martin then triumphantly announced that this proved that his views were true, since none of the alternative views could be proven to be true."
I take your point, but I am supporting the as-far-as-we-know materialist view, and based not on the failure of non-materialist viewpoints.
"Do you see that this is almost exactly the same as your and my current discussion?"
Obviously as a current complete scientific theory of conscious experience doesn't exist, until one does there is always a question mark. But there are some neuroscientific observations related to conscious experience in the brain.
"The only difference is that because you don't know of anything beyond physics, you take that to be proof that there is nothing but physics."
Empirical evidence, rather than proof, and quite a lot of empirical evidence.
"Neither of you want to leave room for human ignorance."
Human ignorance is not an excuse for anything goes though e.g. "disembodied consciousness" is a meaningless phrase - it is not known to mean anything either subjectively or objectively.
" countless logicians who would view Hume's theorem as obviously true."
But classical logic is not natural science.
"If you dispute Hume's theorem, why not explain why, instead of just saying that I have not presented it? "
I believe I have now addressed it as far as I can - matter is all there is, neuroscientists are on the way to showing conscious experience is brain activity, empirical science is not governed by classical logic necessarily.
Steven Evans wrote to me:
Delete>I understand you to mean here that we can't describe subjective experience in terms of objective scientific observations.
No, not quite. I mean that the terms are not even there in any physical theory to refer to experience. You cannot derive a significant conclusion concerning terms that are not present in either the premises or the axioms. This is not a point specific to physics or current physical theories. It is a general theorem in logic.
You cannot derive an “ought” from an “is” because there are no evaluative terms such as “ought” in purely factual statements. That was Hume's point. And, similarly, since theories in physics do not mention experiential terms, nothing can be derived or calculated from physical theories about experience.
I think you are too eager to jump to what you think you know about the physical world and not willing to focus on this theorem in logic.
In a way, it's like Gödel's theorem (although much simpler, of course): no matter what you think you know about the integers, Gödel shows that for any finitely expressible axiom system, certain statements about the integers can neither be proven nor disproven from those axioms. Hume proved a similar point about evaluative statements: no matter how certain you are of your moral beliefs, those beliefs cannot be proven from purely non-evaluative statements.
And Hume's theorem generalizes to the physics/mind problem in an obvious way.
Ought/is = mind/physics.
Steve also wrote:
>Obviously, I don't have handy an objective explanation. But I consider current Physics to be exhaustive up to the current precision of observation. If a more precise empirical theory of matter than the Standard Model appeared it would make no difference to neuroscience.
Probably true. However, most approaches to the quantum-measurement problem – Copenhagen, many-worlds, etc. – have a hidden “mentalistic” side to them, so perhaps solving the quantum-measurement problem will shed light on the mind-brain problem. At least people as smart as Penrose and Wigner seemed to think so.
Steve also wrote:
>Further, brain activity correlating to some extent to reported conscious experience has already been observed, so I would expect that this brain activity will be observed in more and more detail and more overlap will be found between this and reported conscious experience until it is seen objectively to be conscious experience.
Correlation is not identity. Every particle ever observed with a mass of around 0.511 Mev/c^2 has an electric charge of approximately 1.602 e-19 Coulombs. I know of no one who thinks that that mass just is that charge.
You'll notice that I am pretty careful not to say what consciousness is. I merely try to point out those explanations of consciousness which can be shown to fail.
Steve also wrote:
>"disembodied consciousness" is a meaningless phrase - it is not known to mean anything either subjectively or objectively.
I find its meaning much clearer than “quantum superposition,” which I think no one understands, even though I and other physicists use it to correctly predict experiments.
Steve also wrote:
>I believe I have now addressed it as far as I can - matter is all there is, neuroscientists are on the way to showing conscious experience is brain activity, empirical science is not governed by classical logic necessarily.
Again, you confuse correlation with identity, which is a much tougher nut to crack. And, I am afraid that almost all empirical scientists do indeed think that empirical science is governed by “classical logic necessarily” : try to get any of us to take seriously a theory that violates the laws of logic!
Anyway, what I am predicting is not what will be observed in the lab but what facts can be logically derived from existing physical theories. That issue of “logical derivation” is indeed one of the most basic subjects of logic.
Dave
Dave and Steven,
DeleteYou are both talking about logically impossible situations. It is logically impossible that consciousness could have emerged ex nihilo out of non-consciousness (Steven); and it is logically impossible that a special “translation dictionary” could Platonically exist, just hanging around waiting for living things to emerge (Dave).
Why don’t you just say that a primitive awareness was there from the start/always there, just like laws of nature were there from the start/always there?
Some type of “consciousness” is as necessary an ingredient of the universe as laws of nature are necessary, because it is logically necessary for the universe to be, in some way, aware of its own laws and numbers.
Dave,
DeleteThanks for the explanation. But observation is the ultimate arbiter in natural science, so arguments based on logic and Maths while often instructive cannot be decisive, if weak emergence of conscious experience even does contradict classical logic, which is just your assumption. Also, conscious experience is only associated with brains, AFAWeK, so there is no need for the phrase "disembodied consciousness" to enter human discourse ever again. And, people's reputations are irrelevant in argument.
You say charge has not been observed to be matter but that's not the claim, and all structures in chemistry and biology have been shown to be physical matter.
Hume's argument simply highlights an abuse of language. The "ought" is just an expression of our biological programming: "If die, don't do". Hume's ought-is idea is not even close to an interesting idea.
Can we derive "experience" from physics? Empirically, yes. It is not a sensible position to say that part way through billions of years of material evolution or part way through the development of a material foetus suddenly the behaviour is no longer just due to the structure of the matter. The so-called mind-body problem is just the most extreme case of failing to understand the possibilities of gradual change - Darwin showed it to be a non-problem. The empirical evidence of all this is overwhelming.
Summary: So classical logic, Godel, Hume, moral beliefs, "disembodied consciousness", the ontology of the electron are all irrelevant to the discussion and deprecated.
"You'll notice that I am pretty careful not to say what consciousness is"
We know what it is, at least what conscious experience is. That's the one thing we do know. So if it is described to you in natural language or in terms of material brain activity you will recognise it.
(What can logically be derived from physical theories will always have to be confirmed in the lab because the finite precision of measurements means you can never know whether a theory is exactly true physically. Logic and Maths are just shadows of the physical world cast on the brain by coarse perception. As such, their effectiveness in natural science is not at all unreasonable, but of course they are not isomorphic to the physical world.)
Lorraine Ford7:12 PM, June 10, 2020
Delete"It is logically impossible that consciousness could have emerged ex nihilo out of non-consciousness"
It's not a question of logic. And it emerges from a physical brain, not out of nothing.
Steven, can you read? I said: It is logically impossible that consciousness could have emerged ex nihilo out of non-consciousness.
DeleteNo one in their right mind ever claimed that anything emerged ex nihilo, as Steven correctly points out. Consciously is weakly emergent. It is a features that can occur in complex composite systems. Please take your mysticism elsewhere, I'm pretty tired of having to deal with people who don't understand basic logic.
DeleteWell, as I've tried to explain several times without getting much traction, it seems to me that the particular *sensations* of the conscious experience in humans (and probably in dogs, etc.) can only be defined as properties of this universe, which somewhat agrees with Lorraine Ford; but I don't regard the sensations as all that important. Not more important than the functions that consciousness performs, except for this: if there were no sensations of any kind, no way to signify that an experience has ocurred, then there would be no way for consciousness to work, and that work is valuable. So yay for sensations!
DeleteFor me, a computer which performed all the functions of consciousness (which in general is to be the operating system of cogitation--a computer with an operating system directing its basic operations is much more useful than one without such a system) would be conscious. It would experience external inputs and internal state changes. How would it "feel" during these experiences? I don't know, not the same as I do, and why would I care? I'm not a human-experience-chauvanist, or at least I try not to be.
As an example, I am not conscious of lots of things at this instant, including what all my neurons are doing. The reason is: there are no nerves which monitor neurons! You need a sensing mechanism to have a sensation. Similarly I am not conscious of what is going on outside my apartment because at the moment I don't have any sensing mechanisms for that either.
Sensing mechanisms are physical things which work according to known physics. At the moment we don't allow most computers to have many of them besides mice and keyboards, but that could and will change.
Sabine,
DeleteYour claiming that consciousness is “weakly emergent” doesn’t make it true.
What do people mean by the “emergence” of consciousness? I think they mean: 1) subjective experience/feelings, where previously there was not even a skerrick of subjective experience/feelings; and 2) subjective knowledge, e.g. of ones surrounding situation, where previously there was not even a skerrick of subjective knowledge about ones surrounding situation. Logically, I would say that such “emergence” is impossible, and I would say that belief in this type of “emergence” is mysticism. What is missing is a proof of concept that “complex composite systems” could feasibly lead to, even a skerrick of, feelings and knowledge.
Re JimV 7:41 AM, June 11, 2020:
DeleteComputers process symbols of conscious information, just like the words scribbled on a page are symbols of conscious information. Next you’ll be telling us that the words scribbled on a page are conscious.
Lorraine,
Delete"Your claiming that consciousness is “weakly emergent” doesn’t make it true."
Of course not. But I have numerous times explained why claiming otherwise is unscientific, most recently here. You are simply denying scientific evidence.
Lorrraine Ford said to me, "Next you’ll be telling us that the words scribbled on a page are conscious."
DeleteLorraine, please do not make me repeat things over and over again. You know I have to pay a fine in the form of a donation to this site every time I do that. I previously told you that in my opinion, consciousness as we know it requires computational ability, the abilty to be programmed including self-programming, memory, and sensing mechanisms. Words on a page have none of these things. Computers have them to a very limited extent, compared to us, but could have them in principle.
As for symbols, they are not created by magic automatically, but by trial and error and handed down to succeeding generations through forms of memory. The evidence: feral children lack all of these symbols and the ability to learn them. Whereas computers can defeat you in chess and Go, recognize German language, and translate it to English. (So they have demonstrated limited use of the necessary ingredients listed above.)
I read and do my best to understand your arguments. Please try to do the same for mine. Your response above shows you have not bothered to do so or perhaps can't. Frankly, from my end it is like working with a poorly-programmed computer that is stuck in a loop. However, a self-programming computer should be able to work its way out of a loop. Perhaps with the aid of a random-number generator. I have found them quite useful, even in a deterministic universe with only psuedo-random numbers.
I haven't heard anything lately about the fire situation in Australia. I hope it is under control. Let me know if more donations from me would help.
Sabine,
DeleteYou seem to be claiming [1] that a person’s/ living thing’s subjective experience and feelings (e.g. hot, cold, pain, taste, touch) and their subjective knowledge of their surrounding situation IS THE SAME AS OR COMPARABLE TO objective phenomena like temperature, conductivity and sound waves, in that they emerge “from the collective behavior of [the] constituents of [the] system”. So one might wonder why we are not marching for the rights of refrigerators, heaters, electrical conductors, magnets and microphones, as well as the rights of people: I can envisage JimV out there on the streets waving his placard. But seriously, the internal, subjective feeling, knowledge, point of view is NOT accounted for by external descriptions and symbolic/ mathematical representations of phenomena.
In addition to this, the fact that conscious information is inherently logically categorised and ordered (even Trump has a type of logical order to his thoughts) is not accounted for by just saying that “it comes about from the collective behavior of many constituents of a system”.
I am not “denying scientific evidence”. I am saying that, when the issue is properly analysed, this “scientific evidence” doesn’t account for subjective experience and knowledge, and it doesn’t account for the logically ordered nature of consciousness.
1. Sabine Hossenfelder, http://backreaction.blogspot.com/2020/04/what-is-emergence-what-means-emergent.html .
Lorraine,
DeleteI have not made any such claim. I don't even think it makes sense to distinguish subjective from objective, because the only experience I ever have is subjective. I have merely told you that if you claim there is anything about consciousness which is not weakly emergent from the constituents of the brain then you ignore scientific evidence.
"In addition to this, the fact that conscious information is inherently logically categorised and ordered (even Trump has a type of logical order to his thoughts) is not accounted for by just saying that “it comes about from the collective behavior of many constituents of a system”."
Sure it does. I have no idea why you would think otherwise. And in any case, as I have said, what you say is incompatible with evidence.
"I am not “denying scientific evidence”. "
Yes, you are. You just did it again. The brain is made of particles. We know what the particles do. We know that they can not behave according to another law because we had observed this already. It follows that consciousness is weakly emergent. End of story. If you find a brain that isn't made of particles, we can revisit your hypothesis.
Sabine,
DeleteI agree that you “have not made any such claim”. It was me who attempted to describe consciousness as “a person’s/ living thing’s subjective experience and feelings (e.g. hot, cold, pain, taste, touch) and their subjective knowledge of their surrounding situation”. But you claim that consciousness is “weakly emergent”, without even attempting to define what this “consciousness” is.
I’m waiting for 1) a definition/ description of consciousness; 2) a definition/ description of the “constituents of [the] system”; 3) a definition/ description of the “behavior” and the “collective behavior” of the constituents; and 4) a proof of concept that this “consciousness” could “[come] about from the collective behavior of [the] constituents of [the] system”.
JimV,
DeleteComputers process symbols. That’s all you need to know. You seem unable to understand the ramifications of this fact.
Lorraine,
DeleteI do not need to define consciousness to tell you that it is weakly emergent, because I have demonstrated that only weak emergent is compatible with empirical evidence. This cannot possibly be so hard to grasp: Nothing is strongly emergent. Thus, consciousness is not strongly emergent, regardless of what you think it is.
But since you ask, I have a definition here. Not that I think you actually wanted an answer.
Lorraine, I am a human shaped by evolution to care more about my own survival and that of my own species, than any other species which already exists or might exist if we developed it further. Therefore I feel no inclination to march with placards for the rights of various electronic equipment. I don't know what you intend by pretending to believe that I do. Perhaps it is a form of name-calling?
DeleteI understand that computers can process symbols. They can also do calculations and process logic. It seems to me that this is what thinking (that thing that humans do to win chess games and translate languages) consists of. Given that what they can do obviously works and sometimes works better than what humans can do, I see no reason to assume that my own neurons do not work the same way (probably using different algorithms programmed by evolution and training).
In an earlier argument, Dr. Miller said that AlphaGoZero was only exercising a very efficient search algorithm. Well, why can't that be what my neurons are doing to find solutions? It works! Note that the search proceeded by trial and error, which there are numerous examples of in science and engineering , and that biological evolution produced us, with our symbol-processing ability, the same way. Again, it works!
Given a choice between unknown magic and a thoroughly understood process which empirically works, I choose the latter, It seems to me to be the logical choice.
Again, since you or someone will probably bring it up again, so to save a fine, humans have 70-100 billion neurons to do processing with, the smartest dogs about 500 million, and so on down the hierarchy of animals to flatworms with 300, and below, whereas the most powerful super-computer we can yet build has a small fraction of the processing capability that a dog has. The ability of computers to think is established in principle only, at this point. But it is established to my satisfaction, based on the evidence I have seen and have presented.
Also, the question of where humans got their symbol libraries is answered by the case of feral children as presented in the Wikipedia article. We get it by parental training, by schooling, and by self-training which amounts to self-programming. Recall that it took archaeologically similar humans over a 100,000 years to leave traces of the wheel and axle, and that technology snowballs naturally--from wheels to pulleys, windlasses, gears, watermills, computer hard drives, et cetera. (I always feel uncomfortable ending a sentence with an abbreviation--should it be etc. or etc..?)
P.S. (hoping to save another fine) I believe I have addressed all the questions you raised in your June 12 response to Dr. Hossenfelder (what is consciousness, what does it do, what are its constituents/requirements) albeit over several comments at this site. They are my opinions/guesses which could be improved upon, but they satisfy me until something better comes along. That doesn't seem to have helped you in your quest, unfortunately, but they have been presented at this site, and I paid the dues (dues is a better word than fines here) to post them.
Of course one can always raise more questions. Why does 2+2=4? Well, in this universe it does, empirically. The same is true of some aspects of consciousness, as I have said before. Empirically, computers can think well enough to defeat humans at chess and Go. Empirically, if your parents had not taught you language at a young age, you would not be able to learn it.
(This so darn long that I will have to pay a double dues/fine! I haven't saved as much as i had hoped to.)
JimV,
DeleteUnfortunately, you have fallen for a widely held, but false, belief about computers/ AIs. But to my mind, it is a harmful and dangerous belief, that might in the future lead gullible people to mistakenly blame an AI for some terrible event, instead of realising that the true problem is the people behind the AI.
Sabine,
DeleteI like the approach you take in your essay, in trying to arrive at a natural explanation/ description of consciousness. But I disagree with some important details, and so I don’t come to the same conclusions.
Re “This means the rabbit brain must be able to create a reasonably accurate model of its environment: It must have an internal representation that faithfully encodes information about the environment …”:
You didn’t imply this, but I would think that the brain doesn’t encode pre-existing fully-formed information about rabbits, tigers and carrots: i.e. the universe doesn’t know about rabbits, tigers or carrots (or human beings). Instead, the brain/body acquires non-coded information mainly from light and sound waves; and large quantities of this (e.g.) frequency/ wavelength information must in effect be analysed and collated to arrive at a conclusion: rabbit, tiger or carrot is a conclusion. I would think that this rabbit, tiger and carrot information exists in the form of some sort of inherently interconnected logical relationship structure in the brain, but not as codes. The brain/body is not going to waste time and energy creating symbolic codes to represent a rabbit, tiger or carrot because symbolic codes are things that have no inherent relationship to anything else; symbolic codes are only useful for communication with other people (e.g. written or spoken words), and for computers where the codes can be re-represented as electric voltages. So I would think that basic consciousness is (uncoded) relationship information that is subjectively experienced by matter, any matter, but only where the matter has the right type of relationship structure.
Re “…consciousness is not in and by itself a property of a system. Instead, consciousness is relational: Its origin lies in the relation between a system, its environment, and its subsystems.”:
There are no Platonic entities: these types of relationships must seemingly exist as structures in the mind/ brain of human beings or other living things. Presumably there were a minimal number of such relationships when the person was born; new structures originated during the person’s lifetime; and the relationships die when the person dies. Any new relationship information means the creation/construction of new brain structure, but law of nature relationships and their associated numbers are not new information. Any new information must seemingly be built out of (what we would represent as) IF, AND, OR, THEN and ELSE, so I would think that this is an important, natural aspect of the world that we have so far failed to recognise: it has only really become apparent when we started to seriously look at the mind/brain.
Lorraine Ford states "Unfortunately, you have fallen for a widely held, but false, belief about computers/ AIs."
DeleteI wish you would define your accusations more specifically so I could respond to them, i.e., what statements of mine caused you to think I have a false belief about AI's? (One which, based on the rest of your comment, has something to do the dangers of AI mistakes and who is responsible for them.)
Have I not repeated stated that no AI at this point could have the general mental abilities of a dog due to the comparison in processing power (neuron equivalents)? Which in turn is much less than a human child, although children's brains grow in size so they start with fewer neurons than adults. Are children held as legally responsible for their actions as adults are? Why then should we hold even more child-like AI's responsible for the errors in their development and training?
A child, or a dog, for that matter, could, if unrestricted and unmonitored, push the button that would start a nuclear war. AI's could also do bad things and various people have warned against that. How do you get from "AI's could do bad things" to "and then people will blame the AI's instead of the people who gave powers they weren't ready for"?
People's brains make mistakes all the time. AI's do and will also. Where the main responsibility for those mistakes lies is some function of the relative processing power of all those involved (among other considerations), as it is with children and adults. Hamsters and adult humans would be a more apt comparison--except that animals use most of their processing power for interpreting sensory data, coordinating muscles, and things like that, whereas AlphaGoZero only processes Go moves, all the time.
My opinions, such as they are, were formed by my own experience with computers, by my experience thinking of solutions to engineering problems (which involve a lot of trial and error), and by reading various publications, including some papers by Dr. Alan Turing, books by two neuroscientists, and the peer-reviewed paper on AlphaGoZero. From these I have formed a mental model of how my brain works, which involves no magic, and could be implemented on a computer (of a size and with sensors and manipulators which no super computer has, and perhaps never will have).
Dr. Oliver Sachs, in his book, "The Man Who mistook His Wife For a Hat", tells the story of how brain damage destroyed a person's ability to make sense of shapes. The person's visual images consisted of the equivalent of pixels only, not resolved or poorly resolved into shapes. Computer AI programs start the same way, but can be trained to recognize certain pixel patterns, e.g., tigers. So internally they have some relationship of pixels which connotes "tiger" to them, and which they can associate also with the ASCII characters "tiger". Note that relationship was not defined in their code initially, but learned via training exercises. Again, empirical facts like these strongly hint to me that my neurons could work the same way. Why not? Don't let the fact that you can't experience such things happening in your head influence your own opinion--recall that there are no nerves monitoring neurons (with 70+ billion of them working, how could there be?).
Darwin used the empirical facts of artificial selection to see how natural selection could work. I see a similar relationship between AI and biological intelligence. (That doesn't make me Darwin! Lots of people had the same idea much earlier than I did--Dr. Turing, for one.)
(I hope for that sake of my bank account I can let your next accusation stand unresponded to, but it is hard.)
JimV,
DeleteUnlike any other life on earth, human beings are so totally immersed in symbol use (reading, writing, speaking, listening, mathematics, physics, philosophy) that they are no longer even aware that they are using external physical symbols (in sound waves, squiggles on paper). We are almost unconscious of the symbols: the external physical symbols seem to merge with our consciousness of the symbols.
So while a person might be measuring the mass of an external physical object or the frequency of light waves, the external physical symbols we use are not measurable things because they are “hidden” in the patterns of the numbers in the light and sound waves (and in the case of computers, the symbols are hidden in the sets and patterns of high and low voltages). There is no Platonic realm: patterns and symbols do not Platonically exist: they only exist from the point of view of people whose pre-existing knowledge and conscious brain/mind allows them to “see” and interpret the patterns in the light and sound waves.
It’s a matter of human beings knowing themselves, and observing how their symbolic interface with the rest of the world works.
Steven Evans wrote to me:
Delete>Can we derive "experience" from physics? Empirically, yes.
Well, you might like to explain to neuroscientists how you think this can be done! Would save them a lot of work. (The problem is that the process of “deriving” something is a matter of logic: the term “derivation” refers to a logical process. You are guilty of what is technically known as a “category error.” If you were correct that experience could be derived from physics, this would be a logical process requiring no experimental work but only logical thought. Would save neuroscientists an awful lot of difficult lab work!)
Steve also wrote:
> It is not a sensible position to say that part way through billions of years of material evolution or part way through the development of a material foetus suddenly the behaviour is no longer just due to the structure of the matter.
And you know that how? In any case, that is not what I keep claiming. My claim is very narrow: I am making a claim about the semantic capabilities of current theories in physics: they lack the capability to talk about experience. At the very least, you need to add a "translation dictionary" to existing physical theories.
I have repeatedly said that I am agnostic as to whether the experiential aspect of reality arose through some sort of emergence or was always there at some rudimentary level or whatever. I don't know.
And neither do you. You are just guessing. Based on ignorance.
Steve also wrote:
>So if it is described to you in natural language or in terms of material brain activity you will recognise it.
Really? How do you know? I mean, no one has ever actually done that (talk to any neuroscientist: I have, e.g., Gerry Schneider at MIT). It seems exceedingly likely that if you describe “in natural language” the brain processes that you think constitute consciousness, almost no human beings will recognize that to constitute consciousness.
Of course, since you have zero idea of what brain processes supposedly constitute consciousness, we cannot test your assertion. Everything you assert with such confidence is really just sci-fi, rather like Terry Bisson's famous “They're Made Out of Meat” short story. Though Terry is a much more entertaining writer.
Steve also wrote:
>But observation is the ultimate arbiter in natural science, so arguments based on logic and Maths while often instructive cannot be decisive...
Well, almost all physicists disagree with you: almost all of us think that a claim in natural science that can be proven to violate logic or mathematics has therefore been decisively shown to be wrong.
Anyway, you have made clear that you cannot understand Hume's or my argument due to your lack of knowledge of logic. It really is a theorem in logic, so obvious that most logicians would consider it to hardly need proving at all. But you can't grasp it.
On this, I think we can rest: you think that a proof that some assertions violates logic does not refute that assertion. I, and most physicists, indeed most well-educated people, disagree.
Dave
@ PhysicistDave,
DeleteVery well put! I totally agree with the above!
PhysicistDave4:17 PM, June 18, 2020
Delete"Well, you might like to explain to neuroscientists how you think this can be done! "
It isn't known, Dave, because all the data isn't in. Far from it. The brain activity that correlates to reported conscious experience is far from completely described. Tricky to derive something if all the data isn't in. Basic, basic commonsense.
"And you know that how?"
I don't know that my foetus and evolution arguments are true. I'm just saying it's empirical evidence. Why would magic appear halfway through these processes where material develops into a complex structure which is far from completely described.
"I am making a claim about the semantic capabilities of current theories in physics: they lack the capability to talk about experience. At the very least, you need to add a "translation dictionary" to existing physical theories."
And all the empirical evidence is telling us that matter can be arranged in a structure that has conscious experience. It doesn't matter that you personally can't see how it's done.
"I have repeatedly said that I am agnostic as to whether the experiential aspect of reality arose through some sort of emergence or was always there at some rudimentary level or whatever. I don't know."
Mmmmmm, that's not everything you have said. You are backtracking, Dave. You have said that the materialist position is as ideological as the spiritual position. But the original post by Dr. H., which I agree with, is that *as far as we know* conscious experience is weakly emergent. The spiritual position talks about "disembodied consciousness" which is not known to have any meaning to begin with.
"And neither do you. You are just guessing. Based on ignorance."
I admit the ignorance in "as far as we know". That conscious experience is weakly emergent as far as we know is just an expression of empirical facts, it has nothing to do with me. Blame the scientists who did the experiments - you were one of them.
"It seems exceedingly likely that if you describe “in natural language” the brain processes that you think constitute consciousness"
For example, as I type this I can here a voice in my head saying these words. Of course, you recognise this example of conscious experience because you have a similar experience.
PhysicistDave4:17 PM, June 18, 2020
Delete" since you have zero idea of what brain processes supposedly constitute consciousness"
Conscious experience you mean. There are recorded neuroscientific experiments where brain activity is correlated with conscious thought. I'm guessing that'll be it.
"Well, almost all physicists disagree with you: almost all of us think that a claim in natural science that can be proven to violate logic or mathematics has therefore been decisively shown to be wrong."
There is absolutely zero physics which can be shown to be precisely equivalent to Maths. It's impossible. Measurements can only be carried out to a finite precision. Sqrt(2) does not exist in Physics, the Pythagorean Theorem does not exist in Physics, etc., etc.
"Anyway, you have made clear that you cannot understand Hume's or my argument due to your lack of knowledge of logic. It really is a theorem in logic, so obvious that most logicians would consider it to hardly need proving at all. But you can't grasp it."
Hume's ought-is theorem has nothing to do with weak emergence in Physics. Observation is the only arbiter in Physics. If you haven't understood this you don't know what Physics is. What people can dream up in their minds is neither here nor there (see String Theory, Inflation, MWI, "God", "disembodied consciousness", Maths, Logic - none of these are known to exist outside people's minds, 2 of them are useful tools.)
"you think that a proof that some assertions violates logic"
You haven't shown this though. In about 30 posts you haven't shown it. Adding "QED" at the end of a pile of nonsense isn't a proof. When will you show this, Dave. I'm waiting.........
Prof. David Edwards5:23 AM, June 19, 2020
Delete"Very well put! I totally agree with the above!"
No, you don't. You are just upset about the comments I made about your essay. You should be grateful for the feedback instead of being a sensitive luvvie. If you do agree with Dave then provide a proof that weak emergence of conscious experience from a physical brain is logically and therefore physically impossible.
You can't. That's what I thought.
PhysicistDave4:17 PM, June 18, 2020
DeleteSo after 30 posts of claiming you can provide a proof that weak emergence of conscious experience from a physical brain is logically and therefore, you claim, physically impossible, you provide no proof. Not that such a proof exists, but then why did you claim it does for 30 posts? I can see why you are fooled by Galen Strawson's garbage.
What if we simply admit that we as the matter structure are antipodal by nature; alternately at the same time opposite spins, opposite handedness and opposite charges. Quantum state by quantum state a measurement could be at either stage but by symmetries and quantized distances structures see each other at the same stage - conserving charge + parity. Does this idea make any sense? At least it tries to explain that the non-locality we see can be an illusion. The known correlation could be based rather on *global common antipodal locality* than on "spooky" action...
ReplyDeleteSabine wrote: "You cannot suddenly disappear and reappear elsewhere."
ReplyDelete"There is nothing that actually observably travels non-locally."
Quantum objects may be subject to different rules than everyday objects. Nobody has ever watched a photon travel from A to B. Everything that has ever been said or written on this is based on projections of our classical intuitions. It is in fact conceivable that a photon does just that: disappear at A and reappear at B. Both theory (the Feynman propagator) and the EPR/B experiment suggest that quantum physics is non-local. Why should it be local?
Werner,
DeletePhotons, erm, travel with the speed of light. Regarding "non-local". As explain in my video, what physicists mean by quantum physics being "non-local" is that it has EPR correlations and NOT that things suddenly disappear and reappear elsewhere.
Sabine,
DeleteI'm old enough to be fully aware of conventional wisdom. What I was trying to hint at: it is here that the reason can be found why the measurement problem is still unsolved. Didn't you write a piece on how scientists can avoid cognitive bias? Why not put it to a test?
All the best,
Werner
The main reason the measurement problem is unsolved is that many physicists mistakenly believe it is solved by decoherence (though this is widely acknowledged to be wrong) or they think it has been solved by something else or they think it's a philosophical problem.
DeleteI can report from my own student days that I was told it's not a problem unless you are a philosopher. Took me some while to figure out that that's wrong.
I don't understand what you want me to put to a test.
Sabine wrote: "I don't understand what you want me to put to a test."
DeleteYes, the problem is perceiving cognitive bias. If there were an "instant test" to identify cognitive bias, progress in science could be a lot quicker. But looking at the history of physics can be helpful.
Before 1905, understanding electrodynamics was hampered by two absolutely compelling ideas: there cannot be light waves without an aether carrying them, and there must be one universal time that is the same for all observers. After 1905 the question of how light can propagate was put aside (suddenly the aether was no longer necessary!), and by refining our concept of time we have learnt to accept the constancy of the speed of light as a fact of nature.
Understanding quantum theory suffers from two equally "compelling" (obvious, self-evident) ideas: We cannot explain the EPR/B correlations without assuming that photons carry information from the source to the detectors. And "of course" we assume that photons have an existence continuous in time, that between emission and absorption a photon will always be in some "state", in general some "superposition". But the properties of those photons continue to haunt us: they are uncertain, and the results of measurements depend on the detectors as much as on those "properties". Perhaps they'd better be called attributes. Photons have conflicting properties (they are both particles and waves), a feature they share with the aether (which was fluid and solid at the same time).
Today the Michelson-Morley experiment is almost universally seen as proving that there is no aether. There is a similar lesson to be learnt from the Aspect et al. experiments: put aside the question of how information propagates from the source to the detectors, and accept the observed correlations as a fact of nature. If we drop some of the connotations of the word "photon" and put up with just describing the emission and absorption events, we can avoid the EPR/B conundrum. There might be a deeper, possibly superdeterministic theory, but for the present, QFT is best understood as a statistical theory of events and the correlations between them.
Werner
But thg here is no propagation of information. Quantum correlations exceed what you might expect, but they dont require any non locality. The lack of information transfer is why it doesn't violate relativity. This isn't just a dodge, this is the heart of the matter.
DeleteDougOnBlogger wrote: "[t]here is no propagation of information"
DeleteYes, information is not a useful concept here. What the Aspect et al. experiments show is that the photons would have to engage in superluminal communication, if you think of them as having "polarization states" (and thus carrying information with them).
Sabine,
Deleteconcerning the measurement problem we agree in our assessment of decoherence, but for different reasons. I just cannot believe in wave function collapse, because it is based on a misunderstanding of the role of the wave function.
All the best,
Werner
It's an incredibly useful concept! If you want to think of photons communicating, they would be communicating... information. But instead, that is not what is happening.
DeleteFor a while, I thought of this explanation as a dodge, as I suspect you do. 'OK, so you can't send signals, but *some kind of funny business* is happening faster than light!' But it really isn't violating any causality. [A(x),B(y)]=0 for all observables A, B for all space-like separated points x, y, and our notions of locality/causality are preserved. The observables are things that localize. "A photon" is not a thing that is localized to a place, operators are. If you are imagining a process where there is a single photon over on the left and a single photon over on the right, each with a spin, you are wishing for classical mechanics, and the door has closed. Instead, imagine a tensor product in a Hilbert space.
Here's what I understood from a physics lecture, perhaps more intuitive if it's correct. This wasn't explicitly stated but it's what I got from the lecture.
ReplyDeleteWhen measuring entangled photons the two detectors can be both vertical. Then there is a perfect correlation in the spin measurement, when a first photon is measured the second photon has the opposing spin. There is no randomness to this.
When the angle is changed between the two detectors this correlation drops off in a sine wave shape. So when the two detectors are orthogonal this correlation has dropped off over 90 degrees in the sine wave shape. If a vertical spin is detected in a first photon it has no correlation to a horizontal spin measurement in the second detector, it is completely random.
When there is an intermediate angle between the two, say 30 degrees as theta, the correlation has dropped off by the square of a sin theta between them (Or sin^2 theta). Conversely there are more random measurements of spins in the first and second detector the greater this angle theta becomes.
This shows there cannot be a hidden variable, if there is a correlation then a measurement in the first detector gives the opposing spin in the second detector. But often there is no correlation according to sin^2 theta. A hidden variable from when the two photons separated could not "know" when to give a correlation and when not to. Because the detectors are widely separated a first photon cannot know the angle between the two detectors.
So the second photon cannot have from the beginning a knowledge of how often it should be correlated with an opposing spin to the first photon. This can also be tested by changing the angle between the detectors while the photons are moving away from each other.
Ross,
DeleteYou have only part of the argument: you misunderstand what Bell's theorem is really about.
You wrote:
>A hidden variable from when the two photons separated could not "know" when to give a correlation and when not to.
No, that is not really the point. We assume that all each photon knows is what answer it will give if asked its polarization at a specific angle.
If you assume that, you can get correlations.
Suppose, for example, they are both polarized in the x direction, independent of each other. (This can be done, quite easily in fact.) Then if they are both checked in the x direction, they will agree (yes, we are both polarized in that direction). If they are both checked in the y direction, they will both agree (no, neither of us is polarized in the y direction).
The correlations I have just described do not violate Bell's theorem.
It is only certain very particular states that give very particular values of the correlation that violate Bell's theorem.
Those specific values are what makes the difference.
You cannot really grasp Bell's theorem without getting into those arithmetic/algebraic details.
Sorry, but the purely verbal argument you give does not work, and if that were what Bell's theorem actually said, then all theories would violate Bell's theorem and Bell's theorem would just be silly.
Ross,
DeleteAs Dave says, you somewhat misunderstood that. In a deterministic hidden variable theory (that respects statistical independence) you can well have correlations for all intermediate angles. The point is that these will obey a stronger bound than quantum mechanics. Ie, as I say in my video, the quantum correlations seem to be stronger than a local deterministic explanation would allow (again: assuming statistical independence).
ReplyDeleteSuppose I have two balls that collide, they move away at a speed related to each other and in reverse rotation; the speed with which they move away is determined locally, depending on the conditions at the time of the collision; but the rotation does not depend on the collision, it depends on the direction of movement with respect to the surface and that process is non local; for me, in the quantum phenomenon the process of the interaction of the two particles and of both with space is mixed.
If the observed correlations are greater than those allowed by the theory of quantum mechanics, then it is a misnomer to say that (the theory of) quantum mechanics is nonlocal.
ReplyDeleteI know this is how people talk, but technically, grammatically, it seems incorrect ...
Wot? The correlations are greater than those allowed by a deterministic, local theory, not by quantum mechanics.
DeleteI think this tweak in the text might clear up Greg Feild's misunderstanding:
Delete"For this case you can calculate how strongly correlated the measurement outcomes are if the spins had been determined already at the time the original particle decayed. "
→
"For this case you can calculate how strongly correlated the measurement outcomes **would be** if the spins had been determined already at the time the original particle decayed. "
OK, I see!
DeleteThe correlations predicted by QM are greater than those allowed if you assume this, that, and the other.
The other being the Copenhagen Interpretation, which should be scrapped rather than propped up with ideas like Hidden Variables, etc.
Anyway, I've been asked to stop 'contributing', so I will now
honor that request!
Greg
I'm sure this is a basic Physics question, but maybe other lay folk are also wondering..
ReplyDelete"The spin is conserved and the particle decays in two new particles. One goes left, one goes right. But you know that the two new particles cannot each have spin zero. "
Why can't the 2 new particles both have spin 0? 0 + 0 = 0. Spin would be conserved. Is it because this is not physically possible due to considerations of conservation of mass or charge?
"Why can't the 2 new particles both have spin 0?"
DeleteBecause you know they don't. I think you are misunderstanding this. I am saying you know that they cannot each have spin zero. You know this already. Usually it's because they are either electrons which have spin +/- 1/2 or photons which are spin 1 but have no zero eigenvalue. But each of those explanations would only bring up more complications, so I say you just for whatever reason know they can't have spin zero.
I see. Thanks.
DeleteI was confused at first by this too. I think a slight edit makes it clearer:
Delete'"The spin is conserved and the particle decays in two new particles. One goes left, one goes right. Say you know that the two new particles cannot each have spin zero. ""
This comment has been removed by the author.
ReplyDelete> all of this seems to point to the idea that entanglement seems to be more fundamental than spacetime.
DeleteThat is certainly a promising research area. Gravity emerging from entanglement was originally proposed by Sakharov https://en.wikipedia.org/wiki/Induced_gravity and some of the interesting work in that direction has been done by Mark van Raamsdonk (see e.g. https://arxiv.org/abs/1809.01197). So far, however, the progress appears to be slow.
I found Tim Maudlin's "Quantum non-locality and relativity" to be a accessible yet fascinating read on the subject - especially with respect to causality (of apparently non-local effects on entangled particles). The big shortfall: it does not discuss superdeterminism. But then, maybe a 3rd ed. is already on its way.
ReplyDeleteAll the misunderstanding comes from what do we mean by detection in Quantum physic. A detection occurs when the intensity of the signal is above a threshold providing a +1 count measure. A detection is a necessary step of the measurement, it is useful to note that threshold operation destroys the phase of the signal like any measure. Conversely since there is no detection there is no measure and the signal phase and amplitude of the wave functions are still there. Now when you are looking closely to EPR experiment like Aspect's one, the detection or the count measure is not really done at each ends of the experiment but only at the output of the correlation device. It means that the EPR experiment is doing the measure of the correlation of signals (Amplitude phase of the wave function) and not the correlation of the measures , measure of the correlation is not the correlation of the measures in QM, that makes a huge difference.
ReplyDelete"particles which have a common origin but then were separated can be stronger correlated than particles without quantum properties"
ReplyDeleteCan they be correlated via common gravitational wave?
They can possibly be correlated via *standing* gravitational wave - but the concept of standing gw needs much studying.
Deleteno, they cannot
DeleteIf gravitational waves enter into quantum entanglement it is with quantum gravitation or Hawking radiation. Currently the theory of Hawking radiation invokes a semi-classical backreaction on the metric. However, in general this should be quantum mechanical. Hence, the emission of a boson by Hawking radiation may be accompanied by the emission of a graviton that is entangled with the black hole, the boson or maybe both.
DeleteSabine is right that for ordinary QM work gravitons or gravitational waves have no significant role in entanglement.
Is there really any research considering standing gw are some way firmly argumented? I'm sure interested in.
Deletehttps://arxiv.org/pdf/1901.10285
In fact there is quite a new paper. But if related to quantum state correlations, I think it wouldn't be a "gaser" of two massive binaries pumping (hardly coherent pumping can occur like with em-waves with laser) but the scale of oscillations should be planckian (due to uncertainty principle) and phenomenon would be a fundamental property of spacetime.
Quadrupole standing wave is speculative but maybe possible mechanism to conserve antipodal correlations by spacetime. Something about cellular automata can be declared by t'Hooft.
May you explain (or give link) why gravitational correlation is ruled out?
DeleteGravitational waves are classical.
DeleteIndeed, to conserve entanglement the standing wave of spacetime seems to need to be octupole by nature.
DeleteAn octupole can happen if we as matter fluctuate with one rank of matrice as scalar msgnitude just like Higgs vacuum - we could observe only quadrupole...
DeleteSo the "spooky stuff" can be explained given superdeterminism, which would mean Einstein was right all along to be skeptical about the spookiness.
ReplyDelete01-JUN-2020
ReplyDeleteWhat if. . .
one of the entangled photons (L or R) enters a black hole; say a really
tiny one, so that it emerges as a thermal photon some short time later
when the little bh decays into high energy radiations. Would it still be
entangled if the other original photon were still in flight to the detector?
Perhaps a better question is, what if one photon propagates to the detector
in a flat space and the other travels in a less flat space. Wouldn't the difference in the geometry
of the space have an affect on correlated polarization states?
Cheers,
mj horn
1/ The probabilities are different though I think, maybe I still have this wrong. Assume the two detectors start vertically, with a first detector and a second detector. There are two pairs of photons initially polarized vertically, either entangled or not entangled. Call these a first photon going towards the first detector and the second photon going towards the second detector. In each case all photons start with a vertical polarization.
ReplyDeleteIf the two detectors begin vertically then all the photons will be detected in both cases. If the first detector is made horizontal while the second detector remains vertical then the unentangled photons will give different measurements. The first unentangled photons will not be detected and the second unentangled photons will all be detected. The entangled photons will both not be detected.
Instead of this turn the first detector 45 degrees clockwise and the second detector 45 degrees counter clockwise. Now the two detectors will measure the same probabilities whether the photons are entangled or unentangled.
But now turn both detectors say 15 degrees further clockwise so the first detector is now 60 degrees clockwise and the second detector is 30 degrees counter clockwise. They still have 90 degrees between them, though now the angles are asymmetric relative to the initial vertical polarization angle of the photons. There would still be the same number of entangled photons measured at both detectors.
James Ruppley wrote:
Delete>Instead of this turn the first detector 45 degrees clockwise and the second detector 45 degrees counter clockwise. Now the two detectors will measure the same probabilities whether the photons are entangled or unentangled.
James, if you have turned the first detector 45 degrees clockwise and the second detector 45 degrees counter clockwise, then the detectors would have a 90 degree angle between them. In the standard entangled state, you then could not have both photons go through the detectors.
In an unentangled state, they could.
You made some sort of very serious error.
In the standard entangled case, all that matters is the relative angle between the detectors. The absolute angle of the detectors does not matter.
It sounds as if you do not understand this.
2/ But the unentangled photons would have different probabilities at the first detector and the second detector. Because there is 90 degrees between the detectors they can be turned another 30 degrees clockwise so that now the first detector is horizontal and the second detector is vertical. Now with the entangled photons there are no detections, with the unentangled photons there is a 100% measurement at the first detector and none at the second detector. The asymmetric detector positions are then between the initial positions and the final ones.
ReplyDeleteSo the entangled and unentangled photons can be differentiated in this way. If this turn is made when the photons are already moving they could not “know” where the detector would be turned to. If this is asymmetric then the unentangled photons can always be differentiated.
This experiment could be repeated with different angles between the two detectors relative to each other for example 30, 40, 50 degrees. Each gives different probabilities of detections even if the detectors are set after the photons begin moving towards them. The entangled photons cannot “know” which angle the first detector will have relative to the second detector. The unentangled photons cannot “know” either, but they can also be differentiated by making the angles of the detectors asymmetric like this.
So for there to be a hidden variable the entangled photons would have to “know” what the angle between the detectors was going to be and also how asymmetric they are. For example it might initially be 10 degrees clockwise for the first detector and 40 degrees counterclockwise for the second detector. This can be done by only turning the first detector and leaving the second detector at 40 degrees counter clockwise.
Initially then the first detector might be 10 degrees clockwise, after the entangled photons are emitted it might be moved to 20 degrees clockwise. Now there is a 60 degrees difference between the two detectors instead of 50 degrees. The probabilities change according to sine squared theta. The second photon cannot “know” this because the first detector was changed while the second photon was moving. If the angle between the detectors remains at 50 degrees but these are instead both rotated 5 degrees clockwise then the first detector would now be at 15 degrees and the second detector at 35 degrees.
There is still 50 degrees between them, the entangled photons are not differentiated here because the probabilities don’t change. It might also be argued the entangled photons had to “know” this rotation of 5 degrees would occur. But because both detectors are rotated the same amount then each photons would “learn” this at the same time. But when only the first detector is turned then only the first photon “learns” this and cannot transmit this information to the second photon in time.
@Prof. David Edwards
ReplyDeleteActually, perspectivism has a much older pedigree. Jain philosophy has a notion called Anekantevada, which means that reality is many-sided and manifold. It's not surprising that Nietzsche doesn't acknowledge this past history, after he told us he spoke in Zarathrusthas name, when everything he said was, to be bald, anti-Zarathrusthian.
That information can't be transmitted through quantum collapse hasn't stopped experimenters from establishing lower limits on the speed of this collapse.
ReplyDeleteThere was a paper in Nature recently that set a lower bound of at least 1000c, and another a decade ago by a group in China that set this bound a magnitude higher, that is 10,000c.
To link in with your previous post on faster than light 'motion', this is faster than light in spades!!!
I put motion on quotes as this is not motion in traditional sense, of something moving from place to place, that is locally. Personally, it makes me wonder if entanglement can be understood as some kind of non-local topology, whatever that might mean.
Hi Mozibar,
ReplyDeleteIt's fascinating to know that folks are actively trying to measure the speed of wave collapse!
While the 2019 Nature paper "Experimental test of the collapse time of a delocalized photon state" (folks can Google it) measures the speed of wave collapse to be at least 1550 times the speed of light, there is a simple argument that suggests that even ten times that is a smidge on the low side.
As I discussed in a comment to Sabine's April 24, 2020 Backreaction, until a photon is actually absorbed it travels and disperses just like a very weak classical electromagnetic wave. Einstein lenses provide a vivid example of this by focusing the energies of photons even across ten of millions of light years, which in turn makes it possible to view the details of galaxies up to 10 billion light years away.
When interpreted as a weak electromagnetic wave, the resulting wavefront -- the same quite real wavefront that is focused by the Einstein lens -- has in classical terms disipated the energy of the photon over the surface of a sphere whose most distant part is 20 billion light years away (which incidentally is also beyond the visible edge of the expanding universe... hmm!).
So: How quickly can such a photon be converted back into, say, the energy needed to strip an electron from at atom? That's trickier to answer than it might seem, but one way to lock down a solid maximum time is to ask how fast a really good single-photon avalanche diode (SPAD) can respond. For example, a March 2020 paper by John Kosman describes a device capable of transmitting 500 megabits per second using two bits per visible light photon. That works out to 250 million photons per second, or a processing time of 4 nanoseconds per photon. The actual photon absorption time is surely much faster than that, but 4 nanoseconds at least makes a good upper limit.
So at last, the calculation: To collect all of the dissipated photon energy at the speed of light would require 20 billion years. However, no more than 4 nanoseconds are actually available, giving a speed of light factor of 20 billion years divided by 4 nanoseconds, which works out to about...
1.6 x 10^26 c
Which brings me to my final point:
Trying to frame wave collapse as a speed-limit question is probably the wrong approach, mostly because it assumes that the speed of light is more fundamental than wave collapse. But there are some pretty good reasons to suspect that is simply wrong. Given that the speed of light starts fraying a bit even within the framework of QED, it seems more likely that we are dealing with issues so fundamental that any kind of classical-thinking assumption may be inherently risky.
Dear Terry,
ReplyDeleteI'm glad to see that you found the experiment fascinating. You can't imagine both my excitement and delight that people were attempting to come to terms with quantum collapse in terms of traditional physical concepts such as speed, which I'm sure you will agree, is certainly easier to grasp than say something as abstruse as string theory.
To my mind it certainly says something that lower limits have been established and at quite an incredibly high magnitude. Its breathtaking that experimenters can even establish as high speed as 10,000c. It really says something about the imagination of experimenters!
I'm apt to agree with you that the collapse phenomena, is unlikely to be understood simply in terms as such classical concepts as speed. But in terms of investigating this phenomena, though it has been theorised for around a century, it is still too early to say really what it means. Nevertheless, to establish hard experimental results is a real achievement. Personally, I regard our understanding of collapse as analogous to the early days of quantum theory, for example the Bohr atom. It's exciting to think that perhaps there may be here a possibility of establishing some new physics!
ReplyDeleteThe explanation of the correlation of the measurements in the quantum entanglement using a greater signal at the speed of light does not work; because if I carry out the same experiment three times at three different distances, in order to make the result instantaneous, the signal must have three different speeds; which strikes me as witchcraft rather than physical.
Luis,
ReplyDelete“… if I carry out the same experiment three times at three different distances, in order to make the result instantaneous, the signal must have three different speeds; which strikes me as witchcraft rather than physical.”
You are correct of course. By definition, any physics model that invokes velocities faster than c non-relativistic, and thus must give conflicting answers based on viewer frame. That’s why for well over a decade (e.g. Google and translate “Зашифрованные шумом”) I’ve promoted the view that observing a quantum wave function retrocausally (I don’t think the term existed then?) causes the initiating event to transform from quantum to classical, a true hidden variable. That classical variable then remains hidden, but only because no one looked until that observation occurred.
What’s both neat and nicely quirky about this approach is if you can stomach the idea of retrocausally changing the past, the rest of the scenario become fully superdeterministic in the Sabine sense: There’s no further entanglement, just a hidden real variable that was appropriately set by the initial retrocausation event.
Retrocausal variable setting also nicely explains why it’s so hard to violate quantum security: Anyone who successfully breaks in winds up leaving a signed classical-data confession note, one that gets locked into the vault the moment it is sealed!
This would still seem to leave an ambiguity about which of two or more observations was the “first” one that reset the past, but the delightful symmetries of such observations mean that Bell’s inequality works the same no matter which one goes first to “set” the new wave function. Tricky universe!
With that said, it’s also notable that is you assume a canonical frame, which as discussed in an earlier comment you can do without in any way violating the Gang of Four symmetries of Poincaré, Lorentz, Einstein, and Minkowski, then you can also make retrocausality much more mundane by redefining it as nothing more than setting an undefined past state in the canonical frame. Another name for such an undefined state is “a quantum wave function”. In this perspective there is no past, only the present state with widely varying degrees of historical specificity. Computer models do this sort of stuff all the time, but please don’t take that to mean the universe is a computer simulation. Quite the opposite: Computers are devices that make efficient use of what the universe has already provided, with complexity and difficulty: classical bits (persistence) plus space-and-time based bit processing (causality).
A canonical frame with undefined past variables still requires instantaneous non-information-conveying velocities to enable the classical subset to see only the Gang of Four relativistic symmetries, but in a canonical frame there is no longer any ambiguity about such instantaneous velocities. That’s why I was very surprised when Sabine brought up this idea for information-bearing velocities also. I had always assumed that going that far, creating ansibles, would end up creating causality paradoxes, but as long as you assume a canonical frame to resolve the question of which frame is absolutely slower (versus speed-of-light limited “apparently” slower), then even information carrying versions do not violate causality (but do of course violate relativity).
And that, Luis, would also be the eye-of-newt resolution to your concern: If and only if there is a canonical frame, then within that frame the two entangled events would be separated by an absolute right triangle of space and time that would give the “true” velocity of the wave function reconfiguration. This absolute reconfiguration velocity would range from zero for events separated only by time (e.g. two-step reconfiguration of a wave function motionless within the canonical frame, roughly the CMB) to infinite-velocity reconfiguration for two events that have 100% spacelike separation in the canonical frame.
I don't think any retrocausality solution works because both Alice and Bob can be said to be the cause of the wavefunction collapse, and that yields an if and only if scenario. Alice measures on same axis as Bob up if and only if Bob measures down. Bob measures up on same axis as Alice if and only if Alice measures down. Cause is defined usually as an asymmetric relationship: if Alice measures up, then Bob measures down. But not necessarily If Bob measures down, then Alice measures up. The retrocausal relation would also have to travel both ways from Alice to Bob and from Bob to Alice because you can't really pick out one or the other as being first. So there is again nothing really causal in this scenario as there is no asymmetry. If you want to pick out a privileged frame of reference in violation of Einstein's SR, then you could claim an asymmetric and therefore retro causal relation. This seems like you've solved a problem only to create a new one.
DeleteHi A. Hardin,
DeleteGood points, and well stated. It's a bit trickier than it seems, though. I tried every trick I could to come up with a sneaky way to use classical and/or quantum physics to disprove the possibility of a canonical frame. Instead, what happens every time is that the same symmetries that allow any SR to see itself as the fastest-time frame also enable any canonical frame to stay perfectly hidden among the virtual frames.
If you think about it, it has to be that way. Simply designating one frame as "canonical" -- as the one whose space-like state drives all causality for all frames -- changes nothing about how the symmetries of special relativity must still work for all frames.
You might think -- I did think for a while -- that some clever use of Bell's inequality might provide a sneaky way to figure out which frame "really" has the fastest clocks, and thus is the canonical frame.
Alas, what happens is a beautiful ambiguity in which setting either end first produces an equally plausible probability profile for explaining the final results, including Bell's inequality.
At times, the unexpected difficulty of disproving a canonical frame begins to feels like the ultimate cosmic joke, a sort of bait-and-switch on the scale of the universe itself. But I think all that is really going on is simplicity: We are looking at a single, simple underlying reality from diverse points of view. The error we then make is to think that each such perspective represents a separate state or version of the object. It just doesn't. The real reason you cannot cheat is because no matter which part of the elephant you approach blindly and declare to be unique, it's always the same elephant.
ReplyDeleteThank you Terry for your answer. Apparently, on this site, I am the only person who believes that space is a self-organized physical system in a state of equilibrium, a type of matter not unlike particles and in a state of low energy; That makes me believe that there is a particle-space relationship; And I think that is what we observe in the measurement, not an entangled between two particles, but the particles reveal the synchronization of the entire system called space. The one that is totally entangled is space, from my perspective. Thanks again
There's an interesting perspective on non-locality from non-commutative geometry. Basically, in certain such geometries there are no points or neighbourhoods, thus all concepts have to be global! I think this is an important insight into why non-commutativity and non-locality makes an appearance in QM.
ReplyDelete(Mathematically speaking, algebras are dual to geometries. Points in commutative geometries correspond to maximal ideals in the dual algebra. But in there are no maximal ideals in the algebras dual to non-commutative geometries).
The Born rule states that an observable property of a quantum system is defined by a Hermitian operator on a separable Hilbert space, that the only observable values of the property are the eigenvalues of the operator, and that the probability of the system being observed in a particular eigenvalue is the square of the absolute value of the complex number obtained by projecting the state vector (a point in the Hilbert space) onto the corresponding eigenvector. George Mackey had asked whether Born's rule is a necessary consequence of a particular set of axioms for quantum mechanics, and more specifically whether every measure on the lattice of projections of a Hilbert space can be defined by a positive operator with unit trace. Though Richard Kadison proved this was false for two-dimensional Hilbert spaces, Gleason's theorem (published 1957) shows it to be true for higher dimensions.
ReplyDeleteGleason's theorem implies the nonexistence of certain types of hidden variable theories for quantum mechanics, strengthening a previous argument of John von Neumann. Von Neumann had claimed to show that hidden variable theories were impossible, but (as Grete Hermann pointed out) his demonstration made an assumption that quantum systems obeyed a form of additivity of expectation for noncommuting operators that might not hold a priori. In 1966, John Stewart Bell showed that Gleason's theorem could be used to remove this extra assumption from von Neumann's argument.
You are shoving some assumptions in to Born's rule that aren't usually there. It's a matter of terminology of course, but that observables are defined by hermitian operators is usually a separate assumption.
DeleteProf. David Edwards wrote:
Delete>In 1966, John Stewart Bell showed that Gleason's theorem could be used to remove this extra assumption from von Neumann's argument.
But, still, lots of hidden-variables theories are indeed possible – the best-known being Bohmian mechanics, of which Bell was a fan.
Are you just referring to Bell's 1964 argument that such hidden-variable theories must violate Bell locality?
@ PhysicistDave,
DeleteI'm mainly interested in the corollary that the standard quantum logic (i.e., the one coming from the lattice of closed subspaces of a Hilbert Space of dim.>2) doesn't embed in a Boolean logic. The Bohmian Hidden variables model doesn't provide an embedding but a correspondence.