## Sunday, August 18, 2019

### What's more empirical: alternative interpretations of QM or particle physics?

In recent days, I was fully realizing the insanity of the attitude of some ideologues towards the "empirical foundations" of parts of physics – let me call them "deceitful hippies and their protégés and protégées, largely from minorities" – who claim that particle physics and/or things like string theory and supergravity aren't a good enough empirical science for them while the tirades against quantum mechanics and ludicrous new "interpretations of quantum mechanics" must be the future of empirical science.

This combination of claims is totally upside down and the detachment of this combination from the basic facts is absolutely unbelievable. It makes one desperate to see that there are thousands of sufficiently scientifically illiterate laymen in the society who just can't see the absurdity of these claims.

Physics investigates hypotheses and theories that have implications for the observations in principle. That definition is a result of centuries of thinking – although this definition had to be refined by more cautious thinking about "what is scientifically meaningful", let's say the "positivist" or "operationalist" thinking, that finally made it to the physicists' toolkit around the year 1900 and that must be counted as the most important contribution of philosophers (positivists in this case) to physics ever.

OK, the 19th century positivists realized – and within decades, theoretical physicists agreed – that all of our knowledge of the laws of physics as well as the knowledge about the state of the Universe comes from sensory experience interpreted through logic and reason and nothing else.

Without the sensory experience, we just cannot learn anything about the laws of Nature – or about the current properties of physical objects. In science, we learn something from our eyes and ears etc. and using logical, mathematical, probabilistic... reasoning (including Bayesian inference as a method to solve "inverse problems"), we may make conclusions that have some scientific value.

From this point of view, if some statement isn't observable in principle and cannot be deduced from things that are observable in principle, then it may be physically meaningless, like the question whether the "number five is green". (I wrote "may be"; the unmeasurable or auxiliary concepts may still be used in a theory but it's wrong to "demand" that a theory uses them.) Albert Einstein realized that questions such as "whether two events occurred simultaneously", when formulated in this most general or global form, might be physically meaningless and almost certainly are because there's no universal way to experimentally verify the "simultaneity of two events". Instead, his final theory in 1905 – the special theory of relativity – implied that the simultaneity and other things is "relative" i.e. dependent on the choice of the inertial system (choice of the observer, in the special relativistic sense). A particular observer with his inertial system may adjust and distribute clocks that evaluate the simultaneity of events – but observers who are in relative motion with respect to each other may get and actually will get different answers concerning "simultaneity" (and measurements of many other things such as energy, momentum, electric and magnetic fields, and more).

It was a great revolution when he realized that lots of questions that people were formulating before relativity were sloppy or meaningless. Not only the answers but also the questions had to be fixed – to make sure that they're connected with some operations that may be done, at least in principle. Physics shouldn't be expected to answer some philosophical questions that are labeled "legitimate questions" just because they respect the rules of syntax and grammar. Instead, physics answers questions about results of measurements that may be in principle done.

The same basic revolution has affected physics once again, and even more deeply, when quantum mechanics was born. Its most important discoverer, Werner Heisenberg, took Einstein's reasoning a step further. Heisenberg realized that even the value or property of any physical variable (including a Lorentz-invariant scalar) might be and probably is physically meaningless unless or before we actually measure it. So it's only the results of the measurement – that are actually seen on the display of a measurement apparatus or that impacts the observer's thinking – that must be predictable by good enough laws of physics.

The values of observables prior to the measurement don't have to be physically meaningful at all, he realized – and Heisenberg basically acknowledged Einstein as the source of this general philosophical reasoning, although Einstein never really understood why it was correct in this general sense. And indeed, Heisenberg started to work on the assumption that observables prior to the measurement are physically meaningless and a good theory simply won't tell us anything clear about their values!

Instead, Heisenberg represented every observable as a matrix with rows and columns corresponding to mutually exclusive states – in his first choice, the energy eigenstates of atoms etc. – and the matrix entries were some amplitudes that described values of the observable simultaneously connected with the transition from one state to another. The multiplication of observables was inseparable from some "composition of two transitions", which is what the matrix product unavoidably does. The transitions were discrete pretty much by assumption – the jumps between the energy levels could occur but it was meaningless to look "inside" this transition because there's no physically meaningful fact connected with the "details of the process". The matrix elements themselves had to be complex, he realized, and some squared absolute value of them was connected with the intensity of spectral lines or, as Max Born formulated much more precisely, with the probability (or probability density) of transitions between states (that's the description of the matrix elements of evolution operators).

After some thinking, he could write down the whole mathematical theory – the Heisenberg equations of motion for the operators, combined with Born's physical interpretations of the complex numbers that you obtain by these equations. Everything made complete sense even though the Heisenberg picture or matrix mechanics really looks very different from physics as we used to do it. Indeed, Schrödinger's picture or the wave mechanics is more intuitive but it also leads most people to incorrect conclusions – when they start to incorrectly think that the wave function has the same reality status as classical (e.g. electromagnetic) fields.

OK, physics doesn't really have to answer questions that can't be measured – and the value of a measurable quantity before it's measured is a canonical example of the thing that cannot be measured! ;-) If you assume it's not measured yet, then it's not measured, and it's therefore physically meaningless. You would assume that the ideologues who speak about the importance of "empirical evidence" all the time would appreciate this elementary point. But they don't. They are the main ones who "talk the empirical talk but don't walk the empirical walk" at all.

Many of these ideologues insist that physics should study empirical questions. But at the same moment, they insist that physicists should study the values of observables before they are measured or when they are not measured – which is clearly a textbook example of a question that isn't rooted in the empirical science, as judged by the careful positivist eyes. If you define X as something that isn't measured (yet; or at all), then it's just wrong to demand that science says something about X! Period.

Already in the late 1920s, physicists got clearly separated to those who
• understood why these paradigm shifts are unavoidable and irreversible and the new framework of physics should be applied and the tree of physics knowledge should be extended
• those who didn't understand or didn't want to accept the paradigm shift and they wanted to spend – and they wanted others to spend – their time by unproductive attacks and philosophical musings about some desired replacements for quantum mechanics
Which of the two groups did a more empirical work? A more productive work? This is just a rhetorical question, of course, and a commenter who can't see that it's the first group will be immediately banned because only a certain amount of stupidity may be tolerated here.

The first group included the true founders of quantum mechanics – a community which got branched into all of modern physics, the modern hard science as we know it today. So the first group was: Werner Heisenberg, Niels Bohr, Wolfgang Pauli, Paul Dirac, Paul Ehrenfest, Eugene Wigner, John von Neumann... A generation later, the physicists behind the QFTs joined – Richard Feynman, Murray Gell-Mann, Julian Schwinger, ... and so on, and so on.

This productive line of research – that actually acknowledges and celebrates the great paradigm shift that the careful positivist thinking brought us through the quantum mechanical revolution – has led to the Dirac equation, Quantum Electrodynamics, Standard Model, string theory, among many other things; but also to atomic and molecular physics, theory of crystals, superconductors, semiconductors, the transistor, SSD drives, QLED displays, giant magnetoresistance, and dozens of other fields and thousands of discoveries and inventions of the same importance.

On the other hand, the second group included people like Albert Einstein, Louis de Broglie, and Erwin Schrödinger – who have made very important contributions to physics at an earlier stage but who simply lost it at some time – but this prominent group was soon exponentially expanding and destined to incorporate hundreds of people who have never done anything useful for science at all and who consider babbling anti-physics nonsense to be their primary source of income. These days, the popular science is drowning in this cesspool of nonsense which hasn't produced anything in physics. Instead, it has produced dozens of new interpretations and criticisms all of which hope that quantum mechanics will be proven wrong and reversed back to the framework of classical physics where observers aren't needed and, maybe, probabilities aren't needed for predictions, either.

De Broglie, Einstein, and Schrödinger have made those seminal contributions to the quantum theory. But at some moment, they decided that they didn't like the new physics and got decoupled. So they weren't interested in – and they didn't help – the quantum mechanical theories of superconductors, semiconductors, quantum effects in Yang-Mills theory, and tons of other things that I have sketched. They became babblers from the whiskey parties and darlings of moronic journalists instead. To one extent or another, every physicist may just stop doing "real physics" at some point and switch to babbling nonsense at the parties. Gerard 't Hooft made this transition about 20 years ago while Steven Weinberg was switching recently.

All of the hard scientific insights of the modern, fundamental enough, pure and applied physics belong to the first category – the category that just realizes that the insights of quantum mechanics are internally consistent, powerful, impossible to ignore, and almost certainly irreversible. All of the reasoning based on the opposite assumption, namely that there's something really unsatisfying about QM, produce the work that has no empirical content and belongs to the social sciences, humanities, or just plain manipulation of scientifically illiterate laymen whom this "work" is actually addressed to.

I just don't think that intelligent people can fail to see that all the popular literature filled with the anti-quantum whining and dozens of nonsensical "alternative interpretations" is just scientifically nonsensical content produced by the people who aren't really doing proper science and who make their living by selling snake oil to dumb laymen, not by doing science. This kind of stuff is just completely disconnected from any tangible science – pure or applied physics – that has some beef. This humanities-like stuff isn't dissimilar to the grievance studies and indeed, some of the anti-quantum jihadists are doing distasteful neo-Marxist identity politics and similar things at the same moment. (Hard physicists may be SJWs as well but you can see much more clearly that these parts of their behavior are separated from each other. Soft physicists and anti-physics demagogues "seamlessly unify" their crackpot talk about physics with their crackpot neo-Marxist talk about the human society.)

Their assumptions are internally self-contradictory and they contradict basic facts about the experiments, too. They basically assume that the wave function "objectively exists" and therefore "should be measurable in principle". But that's rather clearly untrue – no one has constructed and no one can construct any voltmeter that shows the value of $$\psi(x,y,z,t)$$ for an electron. No one can pour any metallic sawdust around an electron to visualize the wave function. The wave function simply isn't observable. They assume it's observable and the GIGO (garbage in, garbage out) principle can't be fooled. If they assume fundamentally wrong things about Nature, they may probably only deduce nonsense, too. Many of them assume that locality is ultimately broken – but it's totally clear that this assumption contradicts the known observations and will always contradict it. Relativity just holds – and locality holds as a result. The complete denial of this fact is on par with the assumption that the Earth is flat. A physical theory that apparently seems to contradict relativity – that doesn't explain why relativity has worked perfectly so far – is just a non-starter from a serious physicist's viewpoint.

On the other hand, the proper, empirical part of physics does many tangible things – and it's the driving substrate beneath the progress in technology (like all the parts of our electronic devices etc.) as well as pure science (up to quantum gravity and string theory, aside from other cutting edges). I want to emphasize that you should look at the "connectedness" or "common ancestry" of various subfields of physics.

So a funny thing about the healthy physics is that it is totally connected. What do I mean? You can study atomic physics or molecular physics but there is really a smooth transition in between them. Many experts are focusing on these intermediate subfields of physics – something in between atomic and molecular physics; or nuclear physics and string theory; condensed matter physics and string theory; nuclear physics and subnuclear physics (QCD...); quantum optics and quantum computation, and so on. Whenever the people are in between, they basically agree with all the insights that were established in the immediately adjacent fields – they have just a different focus i.e. opinions what is important for them.

While some questions – GUT-scale particle physics or very weak processes caused by dark matter – may be hard to observe in practice, there is clearly a continuum that connects these questions with the testable questions. The Planck energy of $$10^{19}\GeV$$ is high enough but you can get to $$10^{4}\GeV$$ of the LHC by gradually lowering the exponent 19 to 18, 17.... 6, 5, 4. Various particle physicists are lovers of various scales in between and collectively, these physicists form a continuum where no one "qualitatively" contradicts each other. So even GUT scale physics, string theory, and quantum gravity – and the detection of very weak effects of dark matter – is obviously connected with the totally experimentally accessible physics. It's really impossible to separate or segregate somebody in this continuum. There's no natural "border" where the segregation could be done. Questions e.g. about quantum gravity are as scientifically well-defined as those about the Higgs or anything else, e.g. what is the cross section of the W-bosons' or gravitons' scattering $$\sigma(E)$$ at some energies, and any claim that there is something philosophical or non-empirical about these questions is a proof of the speaker's idiocy.

On the other hand, the activity of the "critics and interpreters of quantum mechanics" is disconnected from that connected union of disciplines of modern physics (as sketched in the previous paragraph). You know, no one who really "works" on Bohmian mechanics has ever made important contributions (certainly not contributions using Bohmian mechanics itself) to new phenomena in semiconductors, supersymmetric Yang-Mills theory, new OLED displays, or anything else that is "hard". No one who "works" on many worlds has ever found new isotopes of nuclei or instanton corrections in the SYK model or a resolution of the black hole information loss paradox... No one who works on the Ghirardi-Rimini-Weber "objective collapse" theories has ever constructed a new method to detect dark matter etc.

I want you to focus on the last example in the previous sentence. The "objective collapse" theories are not only "orthogonal" to any physics with beef, like the search for dark matter in WIMP-nuclear collisions. They really contradict each other. The "objective collapse" theories tell you that Nature should often observe itself, by localizing the wave functions of particles. If that's true, the particles' momentum changes (due to the uncertainty principle rules) and sometimes you should get a spontaneous ionization or a spontaneous proton decay (if some quarks are kicked into). All these things would be visible in the huge detectors of dark matter or neutrinos etc. That just doesn't happen. The "objective collapse" theories are really ruled out for any values of the parameters that are significant enough to "solve" any (non-existent) "measurement problem". So the "objective collapse" researchers really have to completely deny the dark matter experiments, otherwise they would see that the fundamental assumptions of their lives of research are demonstrably wrong.

At any rate, there is a virtually perfect separation between the part of physics that produces new insights about string theory or new displays for smartphones (and all such things are rather tightly connected because all the intermediate specializations exist and don't contradict each other, as I argued); and between the would-be part of physics that tries to claim that there is some problem with quantum mechanics. The latter is disconnected from real physics and it is much closer to the humanities and grievance studies – and the kind of people who complain that the Pythagorean theorem is racist. You either do science which means that you understand and appreciate its totally fundamental axioms; or you do anti-science and grievance studies. You can't do both, there is really nothing "in between", and the dumb criticisms of quantum mechanics or relativity (or string theory) belong to the grievance studies camp. It is the activity of parasitic useless activists who generally want to demolish the Western civilization, science, and their major achievements and foundations.

To be able to distinguish between the meaningful physical sciences that do something; and an incoherent, emotional, misguided attack on basic principles of physics – seems to be as straightforward as the task to distinguish between natural sciences and humanities (or grievance studies). And it's this task that many people are apparently incapable of solving. I find the stupidity that is needed for this outcome staggering. I am repeatedly amazed how many morons smack their lips in the comment sections beneath self-evidently untrue, malicious, shallow, demagogic, distasteful diatribes whose content is pretty much the exact opposite of the truth.

And as I repeatedly explained, while there exists no overlap between the hard science (QLED and string theory...) and the anti-quantum babbling, there is a huge overlap between the anti-quantum babbling and all other kinds of anti-science and anti-civilization babbling. For this kind of demagogy to look "marginally defensible", they have to generalize their absolutely unjustifiable criticisms, e.g. those against quantum mechanics, and add new ones.

(It reminds me of Al*x J*nes' comments on Steven Crowder's show a few days ago. He scarily pictured the Pedo Island etc. as "blackmail islands" where the powerful people are gradually immersed into increasingly deep sins and crimes which is how they become members of a de facto Satanist cult – due to the ability of the cult to blackmail them. The cult has many levels-of-a-pyramid or concentric-circles that describe how central you are for the cult but they ultimately want the whole society to be a non-central part of the cult. Sometimes it sounds as a conspiracy theorist's thinking but to say the least, even if that's the right word, he is a very smart conspiracy theorist, indeed.)

Because of Bell's theorem or any equivalent argument, if someone complains about the "subjective" character of the wave function in quantum mechanics, a basic postulate of quantum mechanics, he or she must also complain about relativity because Bell's theorem implies that assuming that the results objectively exist prior to the measurement (and the correlations are as high as predicted by QM), non-local influences must in principle exist as well, and therefore special relativity must be wrong, they say.

Similar, completely wrong, would-be arguments also imply that the general theory of relativity is wrong – and anything else that matters in science is wrong. If this deterioration and brainwashing of the society continues, of course they will claim that 1+1 isn't 2 soon. But it's not true. All these "unwanted claims" are either precisely true, like the universal postulates of quantum mechanics, or they're precisely true assuming some parameterization of physics (e.g. the diffeomorphism symmetry of GR), or they're perfectly true in some approximate limiting theories that may be extracted from the precise ones (e.g. the form of Einstein's equations as a long-distance limit of a fundamental theory). In particular, quantum mechanics is true and compatible with the general relativistic explanation of gravitational phenomena – and string/M-theory shows how they're merged exactly. Special and general relativity continue to hold "precisely" if you define them as appropriate properties or limits.

In science, it's normal and unavoidable to work with competing theories and competing answers to questions or localized classes of questions. But the social phenomena that I discussed above are different: We are increasingly seeing a growing gap between science that actually produces new insights and inventions on one side; and anti-science (that obviously calls itself science but it is anti-science) that attacks the real science from the first part of this sentence. There is nothing in between these two camps – just a huge gap – and the correct camp of the West and hard science contains pretty much everything that is valuable in our world.

An increasing fraction of the public discourse is controlled by anti-scientific demagogues and harmful freeloaders who attack science instead of contributing to it and who emit an increasing fraction of fundamentally wrong claims and would-be theories to the public discourse. They are separated from proper science by a quickly deepening gap. At some level, it is unavoidable that this gap is growing and deepening. These charlatans have simply started to make living by spreading lies and when someone does so, he or she is often forced to lie increasingly often, and to emit lies that are increasingly outrageous and dishonest (in analogy with J*nes' "blackmail islands").

Under normal circumstances, this deepening gap could be a good thing because the liars could be surrounded and sucked into Hell. However, the Western society is so unhealthy that this lying clique of anti-scientific (and generally anti-Western) charlatans may very well take over. We need to tame or cure this tumor before it liquidates us.