Sean Carroll has unsurprisingly endorsed an offensively idiotic Socratic dialogue
- Neo, a caricature of a modern (therefore "Neo") physicist working in a practical discipline relying on quantum mechanics (perhaps particle physics)
- Nino, an intellectual who died in 1900 but was recently resurrected as a zombie.
Needless to say, the nonsense emitted by Nino is supported by the writer of the dialogue Mr Garrett, too. And it's quite some pile of garbage, indeed.
Garrett starts with an introduction that explains the characters and his "Einsteinian" view:
It is embarrassing that we can predict properties of the electron to one part in a billion but we cannot predict its motion in an inhomogeneous magnetic field in apparatus nearly 100 years old.This fact is not "embarrassing". Instead, this fact – that random results such as the path of a randomly polarized electron in a magnetic field cannot be predicted – is a part of the most important discovery in the 20th century science.
Garrett, before he calls himself Nino, continues:
It is tragic that nobody is trying to predict it, because the successes of quantum theory in combination with its strangeness and 20th century metaphysics have led us to excuse its shortcomings.The reason why no serious physicist is trying to predict the results of similar quantum mechanical experiments that seem random is that science has established that they are random, indeed. To try to derive the results from some "causes" has been shown to be exactly as foolish as astrology. People who do this stuff are simply not serious scientists. They are stuck in a medieval world view that has been debunked for 90 years.
Nino and Neo start to talk about the ultraviolet catastrophe and the Stern-Gerlach experiment (spin in a magnetic field) when the controversy quickly emerges.
Nino: Probabilistic prediction is an improvement on my 19th century physics, which couldn’t predict anything at all about the outcome. I presume that physicists in your era are now looking for a theory that predicts what happens each time you put a particle through successive Stern-Gerlach apparatuses.Note that Nino "presumes". However, it is a defining feature of science that the things one "presumes" are working hypotheses that may be invalidated – falsified – by the evidence. And indeed, that was the fate of this Nino's "presumption", too. Random outcomes of the quantum experiments are truly random. They can have no deterministic causes.
Neo: Actually we are not. Physicists generally think that quantum theory is the end of the line.
We can see that – especially when we analyze experiments testing entanglement. A deterministic mechanism would need to send signals that are faster than light to maintain all the observed correlations. And since 1905, we have known that signals faster than light may be interpreted (if we use a different inertial system) as signals that propagate backwards in time – and they would imply a logical inconsistency.
The technical part of these proofs has been advertised many times. But the real problem is that zombies like Nino, Garrett, or Carroll just don't give a damn about any evidence, any proofs, any rational argumentation. The belief that the world is a deterministic, basically classical system is a dogma for them – much like the existence of an Allah is a dogma for the jihadists. But science simply isn't a mindless rationalization of dogmas.
Nino: In that case they’ve been hypnotised by it! If quantum mechanics can’t answer where the next electron will go then we should look beyond it and seek a better theory that can. It would give the probabilities generated by quantum theory as averages, conditioned on not controlling the variables of the new theory more finely than quantum mechanics specifies.The right words are not "hypnotised by quantum mechanics" but "persuaded by the evidence". Quantum mechanics fully, unambiguously, consistently, and satisfactorily answers everything about the character of this information – random outcomes of such experiments. The answer is that the outcomes are genuinely random and no deterministic explanations may exist.
Nino's comment is a sketch of an alternative explanation and it has been shown that all explanations fitting this skeleton are wrong. In science, one may make a guess – like Nino's guess – but one may also show that most guesses are just unequivocally wrong and Nino's guess is an example of that.
Neo: They are talked of as ‘hidden variables’ today, often hypothetically. But quantum theory is so strange that you can’t actually talk about which detector the atom goes through.The word "strange" is one of the reasons why I called Neo a "caricature" of a modern physicist.
In reality, there is nothing "strange" about the quantum mechanical description of the status of the particles, detectors, and results. It's how Nature – the non-strange Nature around us – works and an intelligent undergraduate understands these rules after one or two introductory classes of a quantum mechanics course.
Nino: Nevertheless only one of the detectors goes off. If quantum theory cannot answer which then we should look for a better theory that can.A theory that has a deterministic cause for all these random results has been proven to be a worse, not better, theory. In particular, it may be shown that such a theory is unavoidably wrong because it conflicts with relativity, an important principle extracted from all the experiments ever done, and such a conflict makes a theory dead, not better.
In science, the adjectives "better" and "worse" are assigned to theories not according to some subjective appraisals by deluded dogmatic zombies but according to the evidence – compatibility with the empirical data and the internal consistency etc. In Nino's vocabulary, things related to his beliefs may be "better". But according to science, these things are called "junk".
Nino: Its variables are manifestly not hidden, for I see their effect very clearly when two systems with identical quantum description behave differently. ‘Hidden variables’ is a loaded name. What you’ve not learned to do is control them. I suggest you call them shy variables.First of all, the term "hidden variables" was introduced by David Bohm, not by a modern physicist fully familiar with quantum mechanics, so it's silly to criticize the Copenhagen-like folks for this term.
Second of all, the term "hidden variables" is totally reasonable for the theories that Nino the zombie believes. Bohmian mechanics is the most well-known type of hidden variable theories. It claims that a particle is associated with a classical information about the location, \(x(t)\), and a classical pilot wave \(\psi(x,y,z,t)\).
When we measure the electron, we may see it and the value of \(x(t)\) at one moment. But we're still incapable of "measuring" the pilot wave \(\psi(x,y,z,t)\) – infinitely many complex numbers (one per each spacetime point). If the randomness were explained by some extra variables, an overwhelming majority of those extra variables would unavoidably remain unobservable. They would also make the heat capacity of all objects insanely high (and infinite), in contradiction to observations, and lead to many other sicknesses.
Needless to say, Neo, the caricature of a modern physicist, failed to explain why the term "hidden variables" is appropriate and why the zombie's criticism of it is flawed.
Neo: Those who say quantum theory is the end of the line argue that the universe is not deterministic – genuinely random.One may perhaps argue that the word "random" is vague – although I would insist that the axiomatic foundations of the probability calculus and mathematical statistics etc. are as rigorous as the foundations of any other discipline of mathematics.
Nino: It is our theories which are deterministic or not. ‘Random’ is a word that makes our uncertainty about what a system will do sound like the system itself is uncertain. But how could you ever know that?
But the non-random alternatives may be defined in a clear way and they may be falsified. Nino's belief that there was no way to decide whether hidden variables existed may have sounded plausible shortly after 1925 but it was later clearly seen to be wrong. It is possible to decide the question whether the randomness is due to hidden variables and the answer provided by science is unquestionably No.
Neo is trying to explain to the zombie why the hidden variables needed to reproduce the observed correlations would have to be non-local. (The explanation is just so-so.)
Nino: Nonlocality is nothing new. It was known as “action at a distance” in Newton’s theory of gravity, several centuries ago.Right. There is this widespread verbal excuse by the hidden-variable jihadists that the nonlocality could be "weak" and therefore "pretty much OK with the tests of relativity" etc. But the problem is that any nonlocal influence may be quantified and the correlation in the EPR-like experiments remains perfect regardless of the distance. So the non-locality of the hidden variables that could reproduce the correlations wouldn't decrease with the distance. The violation of relativity would always be of order 100 percent and that's clearly excluded.
Neo: But gravitational force falls off as the inverse square of distance. Nonlocal influences in Bell-type experiments are heedless of distance, and this has been confirmed experimentally.iv
Nino: In that case you’ll need a theory in which influence doesn’t decay with distance.
Neo: But if influence doesn’t decay with distance then everything influences everything else. So you can’t consider how a system works in isolation any more – an assumption which physicists depend on.
Nino: We should view the fact that it often is possible to make predictions by treating a system as isolated as a constraint on any nonlocal hidden variable theory. It is a very strong constraint, in fact.Right. It's such a strong constraint that it kills all hidden-variable theories.
Neo: An important further detail is that, in deriving Bell’s inequality, there has to be a choice of how to set up each apparatus, so that you can choose what question to ask each particle. For example, you can choose the orientation of each apparatus so as to measure any one component of the angular momentum of each particle.Right.
Nino: Then Bell’s analysis can be adapted to verify that two people, who are being interrogated in adjacent rooms from a given list of questions, are in clandestine contact in coordinating their responses, beyond having merely pre-agreed their answers to questions on the list. In that case you have a different channel – if they have sharper ears than their interrogators and can hear through the wall – but the nonlocality follows simply from the data analysis, not the physics of the channel.Except that all the tests work even when the two experiments demonstrably don't hear each other through the walls. Maybe others don't know whether there is a clandestine communication between them – but they do know that there's none. That's why they, the experimenters, may determine that the zombie's conspiracy-theory explanation is simply wrong. And yes, the experimenters – and not some external conspiracy theorists – are those who are supposed to validate or invalidate hypotheses about Nature.
This meaningless discussion about the "clandestine communication" between the experimenters goes on and on and on.
Nino: Since then you haven’t found hidden variables underneath quantum mechanics in nearly 100 years. You suggest they aren’t there to be found but essentially nobody is looking, so that would be a self-fulfilling prophecy.On the contrary, the number of people who have been talking about hidden variables and similar garbage has been higher than the number of serious physicists. They've been looking and they haven't found anything because there is no hidden-variable theory that would make any sense or have any value.
Instead of searching for the evidence in favor of a predetermined answer to a question (whether hidden variables exist), a scientist should be impartial and look at the evidence in both (or all) ways. The credible scientists have done so in this case as well and the conclusion of this impartial research is that hidden-variable theories are wrong and their advocates who continue to exist in 2015 are pseudoscientific biowaste.
Nino may find it inconvenient that science has demonstrated that his ashes should have been kept in the urn because they're worthless but this discomfort doesn't make the conclusion of the scientific research any less valid.
Otherwise, more generally, the comment about the self-fulfilling prophecy is really cute. What's going on is that scientists are investigating at all possible directions that remain viable at a given moment of time. And when they eliminate some possibilities, they continue with the remaining viable hypotheses and theories only. In this sense, the research is being directed in a certain way – and it has to be. If this "self-fulfilling prophecy" didn't exist, it would mean that the scientists don't care about the evidence and insights they have already found at all.
On the other hand, there is a sick version of the "self-fulfilling prophecy". It's wrong if someone is only looking for the evidence of one kind and wants to ban all research that would imply or assume another answer. But it's exactly Nino the zombie and his real-world soulmates, not the proper quantum mechanical physicists, who are guilty of this misconduct.
Nino: If the non-determinists had been heeded about Brownian motion – and there were some in my time, influenced by philosophers – then the 21st century would still be stuck in the pre-atomic era.This is complete nonsense. The truth is the opposite: the Brownian motion is random and even in the classical 1905 papers explaining it, it is correctly assumed that there exists no cause for a particular trajectories of the pollen particles and only the statistical or probabilistic predictions may be made. In this sense, even this piece of classical physics was deriving facts about Nature from a fundamentally probabilistic reasoning, much like all research in quantum mechanics.
Moreover, the existence, stability, and all properties of atoms may only be derived from (probabilistic) quantum mechanics so the zombie needs quite some chutzpah to claim that the quantum mechanical physicists are those who would be against the discovery of the atoms.
Nino: If one widget of a production line fails under test but the next widget passes, you wouldn’t say there was no reason; you’d revise your view that the production process was uniform and look for variability in it, so that if you learn how to deal with it you can make consistently good widgets.Sorry, Neo the caricature, but all phenomena in Nature, including production lines, are ultimately based on quantum processes. Some complex enough processes may have more detailed reasons for one result or another, however; the most elementary processes in quantum physics (e.g. particle physics) are still random and there is no room for any layers of extra explanations. These results are genuinely random and it is misguided to look for a deterministic cause.
Neo: But production lines aren’t based on quantum processes!
Nino: But I’m not wedded to quantum mechanics! I am making a point of logic, not physics.Sorry, this is not possible. One always needs some physical theory or framework if he wants to talk about Nature. And the framework may be right or wrong. It is not possible to determine correct insights about Nature by pure logic. And in particular, it is surely impossible to find the correct answers to questions about fundamental physics by proposing naive, demagogic, simple-minded, and ultimately flawed analogies.
Nino: Quantum mechanics has answered some questions that my generation couldn’t and therefore superseded the theories of my time, so why shouldn’t a later generation than yours supersede quantum mechanics and answer questions that you couldn’t?Because the class of theories that you want to "supersede" quantum mechanics is exactly the class that has been falsified by physics – much like your life ended in 1900 – and death and falsification are irreversible processes. If there is going to be a newer theory in the future, it will be even more distant from classical physics (and/or hidden variables), not closer.
There is extremely strong evidence that the basic framework of quantum mechanics is here with us to stay and it can't be deformed at all.
Nino: It is scientific suicide for physicists to refuse to ask a question about the physical world, such as what happens next time I put a particle through successive Stern-Gerlach apparatuses.This conspiracy theory mixes the cause and its effect. The zombie says that people are eliminated from the list of credible physicists because they promote things like hidden-variable theories. But the actual causal relationship is exactly the opposite one: Some people promote things like hidden-variable theories because these people completely suck as physicists. Their attraction to wrong ideas is a consequence, and not a cause, of their defective brains.
Neo: Not so fast! Nolocality isn’t the only radical thing. The order of measurements in a Bell setup is not Lorentz-invariant, so hidden variables would also have to be acausal – effect preceding cause.Neo is a caricature. The non-locality and the breaking of the Lorentz symmetry are in no way independent. Within the framework of relativity, nonlocality and acausality may be seen to be the very same thing. A nonlocal i.e. acausal influence is the most straightforward example or proof of the Lorentz symmetry violation.
Neo is explaining the Lorentz symmetry and relativity to the zombie.
Nino: [Einstein] was obviously a brilliant physicist!Not really. Bell's theorem was just a technical footnote to the EPR paper. Einstein had always believed that quantum mechanics and the hidden-variable theories were very different and distinguishable. Bell just found an unsurprising example of a situation where the two classes of theories may be distinguished. It wouldn't have shocked Einstein.
Neo: Yes, although he would have been shocked by Bell’s theorem.
What could have shocked Einstein is the experimental fact that when the experiments are allowed to speak, quantum mechanics passes all the tests while the local hidden variables fail.
Neo: Today we say that a theory must not admit closed time-like trajectories in space-time.If a theory predicts any "acausal situations", then it is logically inconsistent. It is dead. A zombie may insert his head to the sand, overlook this fact, and keep on promoting the dead theory – but the fact doesn't disappear because of that.
Nino: But a working hidden-variable theory would still give a reason why the system behaves as it did, even if we can’t access the information needed for prediction in situations inferred to be acausal.
The discussion continues by a confusing exchange about the redundancies, unphysical part of the degrees of freedom, and gauge symmetries. The similarities and differences between the classical redundancies and the unphysical character of some issues in quantum mechanics are not properly articulated.
Neo boasts about the successes of the Standard Model while the zombie insists on his 19th century views.
Nino: But I’m not committed to quantum mechanics!It is not too important whether a stupid zombie who should have stayed in the urn is committed to quantum mechanics. It's much more important that Nature is committed to quantum mechanics, a fact that science has established.
Nino: This result means that the hidden variables aren’t just the values of all the system variables, but comprise something deeper that somehow yields the system variables and is not merely equivalent to the set of them.Pure fog. The information is either classical or not. If it is classical, the information distinguishes some possible states in a set of possibilities that we call the phase space. The goal of the fog above is to suggest that there exists some loophole that invalidates various proofs but no such loophole exists – only the defects in Nino's thinking do.
Neo: Some people suggest that reality is operator-valued and our perplexities arise because of our obstinate insistence on thinking in – and therefore trying to measure – scalars.But the individual matrix entries of operators describing the reality are not observable. They are only templates to calculate the probabilities of phenomena that are observable.
Nino: An operator is fully specified by its eigenvalues and eigenfunctions; it can be assembled as a sum over them, so if an operator is a real thing then they would be real things too. If a building is real, the bricks it is constructed from are real. But I still insist that, like any other physical theory, quantum theory should be regarded as provisional.
You insist on theories that have been falsified by science because you're a stupid, stubborn, irrational, and obnoxious zombie who should better return to the urn, along with the real-world soulmates of yours.
Neo: Quantum theory answered questions that earlier physics couldn’t, such as why electrons do not fall into the nucleus of an atom although opposite charges attract. They populate the eigenspectrum of the Hamiltonian for the Coulomb potential, starting at the lowest energy eigenfunction, with not more than two electrons per eigenfunction. When the electrons are disturbed they jump between eigenvalues, so that they cannot fall continuously. This jumping is responsible for atomic spectrum lines, whose vacuum wavelength is inversely proportional to the difference in energy of the eigenvalues. That is why quantum mechanics was accepted. But the difficulty of understanding it led scientists to take a view, championed by a senior physicist at Copenhagen, that quantum mechanics was merely a way of predicting measurements, rather than telling us how things really are.OK enough.
Nino: That distinction is untestable even in classical mechanics.In classical mechanics, the distinction is untestable because even the probabilistic description of classical mechanics (with a probability distribution on the phase space) is compatible with the extra assumption that the "actual, correct" point on the phase space is knowable or known to an agent.
However, in quantum mechanics, the distinction is testable because quantum mechanics is logically incompatible with the extra axiom that the observables (even some of them) have well-defined values prior to the measurement.
Classical physics was compatible with both attitudes – science describes "how things are" or "what we may know and predict". But quantum mechanics is only compatible with the latter. That's how it works. And it works differently in quantum mechanics than it did in classical physics because quantum mechanics is a different type of a theory than any theory in classical physics.
I will omit the zombie's babbling about metaphysics, history of Europe including the wars, and religion because it's just way too stupid for this blog. Much like his real-world counterparts, the zombie is clearly unable to focus his reasoning. Neo's reply involves wars and some modern technologies. It is too chaotic for TRF, too.
Nino: That’s a woeful confusion – information about what? As for deeper explanation, when things get weird you either give up on going further – which no scientist should ever do – or you take the weirdness as a clue. Any no-hidden-variables claim must involve assumptions or axioms, because you can’t prove something is impossible without starting from assumptions. So you should expose and question those assumptions (such as locality and causality). Don’t accept any axioms that are intrinsic to quantum theory, because your aim is to go beyond quantum theory.No, the scientist's task is not to "go beyond quantum theory". The scientist's task is to find the truth about Nature – whatever it is. And one of the most important truths about Nature that has been found in the 20th century is that Nature obeys the laws of quantum mechanics. It is not possible to do modern physics in 2015 while ignoring this fact. Everyone who ignores it is a brain-dead zombie.
Moreover, again, the suggestion that the hidden variables etc. go "beyond quantum mechanics" is just very stupid demagogy for the most brain-dead zombie audiences. It's the other way around: quantum mechanics went "well beyond classical physics" and hidden-variables theories are just some (because of technical details) new types of theories in classical physics. So hidden-variable theories are an attempt to revert the progress in science and make zombies the rulers of the world again. This is not how science works because the progress in science – composed of falsification of invalid and too naive theories – is irreversible.
Ironically enough, Neo promotes the "many worlds interpretation", holy cow.
Nino: We couldn’t observe the other universes, so this is metaphysics, and more fantastic than Jules Verne! What if the spectrum of possible outcomes includes a continuum of eigenvalues?The zombie's reaction is absolutely irrational. Shouting expletives such as "metaphysics" is not a way to prove or disprove an idea. The "many worlds interpretation" Ansatz is ultimately wrong just like the hidden-variable theories but it is not "more wrong". It's enough to be "normally wrong" for a hypothesis to be dead.
Nino, the zombie, actually offers some reasonable criticisms of the "many worlds interpretation". The roles of the characters in this dialogue become completely incoherent. The discussion turns to the exchanges about consciousness and even "vitalism". I don't want to go into that topic that's been covered so many times on TRF.
Neo: Your deterministic viewpoint has been disparaged by some as an outmoded, clockwork view of the universe.Sorry, determinism hasn't inspired any progress in physics after your death. In science, we don't worship "metaphysical assumptions" that are obliged to stay with us forever. In science, we are impartially evaluating the truth value of assumptions. And classical determinism, while a property of approximate theories that were good enough for centuries, has been shown to be a wrong assumption at a more fundamental level.
Nino: Just because I insist on asking where the next particle will go in a Stern-Gerlach apparatus? Determinism is a metaphysical assumption; no more or less. It inspires progress in physics, which any physicist should support.
A zombie may repeat that astrology has been so inspiring and wonderful but genuine 21st century scientists simply don't believe this set of "metaphysical assumptions". They consider the framework of classical physics as a fundamentally incorrect one, too. That's the main outcome of the previous century in physics.
Neo: Unlike electromagnetism, however, the gravitational field itself has not yet been successfully quantised, hindering the marrying of it to other forces so as to unify them all.Neo clearly misunderstands the character of the difficulties in quantum gravity and the status of all the research in this area, too. But again, Neo isn't a good physicist – he's just a caricature invented by a subpar pseudoscientist.
Nino: But it’s still not a complete theory if it’s a quantum theory. Please say more about that very small dense stage of the universe which presumably expanded to give what we see today.Sorry, it's the other way around. Science has determined that if a theory is complete, its being a quantum theory is a necessary condition. If it were not a quantum theory, it would prove that the theory isn't complete.
An exchange about inflation and whether or not it involves or eliminates nonlocality.
Nino: It is magnificent that you can predict properties of the electron to nine decimal places, but that makes it more embarrassing that you cannot tell something as basic as which way a silver atom will pass through an inhomogeneous magnetic field, according to its outermost electron.Again, no. It's been established that the path is genuinely random and only probabilities may be predicted. There's nothing embarrassing about this result. It is a very important result in science that brought us at a much higher level than the level known to the 19th century physicists.
Nino: That incapability should be an itch inside your oyster shell. Seek a theory which predicts the outcome when systems having identical quantum specification behave differently.One may start with similar dogmas – e.g. that a scientist is obliged to find the elixir of youth or explain all social interactions using astrology etc. But many of these assumptions turn out to be wrong. It's the case of astrology and it's the case of Nino's outdated assumptions, too.
Nino: Don’t let anything put you off because, barring a lucky experimental anomaly, only seekers find. By doing that you become part of a great project.Sorry, if a person "doesn't let anything put him off", then he is not a scientist, by definition. To listen to the evidence is a defining feature of any scientist
So, Nino, now return to the urn, don't contaminate the 21st century world whose science has become too conceptually difficult to you, accept that the people pointing out that you and your followers in the real world are piles of trash, and just go away and take these obnoxious dishonest dogmatic jerks with you to the cemetery!
Thank you very much.