Edge.org essays on explanations

I remarked that physicists keep looking for hidden variables, in spite of an 80-year consensus that such theories contradict quantum mechanics. Satyajit Das writes in response to the annual Edge.org question:

In 1927, Heisenberg showed that uncertainty is inherent in quantum mechanics. ...

The play repeats their meeting three times, each with different outcomes. As Heisenberg, the character, states: "No one understands my trip to Copenhagen. Time and time again I've explained it. To Bohr himself, and Margrethe. To interrogators and intelligence officers, to journalists and historians. The more I've explained, the deeper the uncertainty has become."

In his 1930 text The Principles of Quantum Mechanic. Paul Dirac, a colleague of Heisenberg, contrasted the Newtonian world and the Quantum one: "It has become increasingly evident… that nature works on a different plan. Her fundamental laws do not govern the world as it appears in our mental picture in any direct way, but instead they control a substratum of which we cannot form a mental picture without introducing irrelevancies."

Dirac was right. It is very hard to form a mental picture of the atom without introducing irrelevant hidden variables.

I think that today's search for hidden variables is a misguided attempt to validate some flawed mental picture. They are usually not explicit about their faulty assumptions.

For an example of someone who expects mathematics to explain everything, Antony Garrett Lisi writes:

What is tetrahedral symmetry doing in the masses of neutrinos?! Nobody knows. But you can bet there will be a good explanation. It is likely that this explanation will come from mathematicians and physicists working closely with Lie groups. The most important lesson from the great success of Einstein's theory of General Relativity is that our universe is fundamentally geometric, and this idea has extended to the geometric description of known forces and particles using group theory. It seems natural that a complete explanation of the Standard Model, including why there are three generations of fermions and why they have the masses they do, will come from the geometry of group theory. This explanation does not yet exist, but when it does it will be deep, elegant, and beautiful — and it will be my favorite.

Yes, we have geometric description of the known forces and particles, but I am not so sure that the our universe is fundamentally geometric.

Eric R. Weinstein also promotes the geometrical theory of everything:

But the most important lesson is that, at a minimum, Einstein's minor dream of a world of pure geometry has largely been realized as the result of a large group effort. All known physical phenomena can now be recognized as fashioned from the pure, if still heterogeneous, marble of geometry through the efforts of a new pantheon of giants. Their achievements, while still incomplete, explain in advance of unification that the source code of the universe is overwhelmingly likely to determine a purely geometric operating system written in a uniform programming language.

Lisa Randall writes:

The Standard Model's success nonetheless illustrates another beautiful idea essential to all of physics, which is the concept of an "effective theory." The idea is simply that you can focus on measurable quantities when making predictions and leave understanding the source of those quantities to later research when you have better precision.

Not only physics. This idea has been essential to all of science for millennia. She is just describing a theory that has been stripped of its pretentions of being some sort of perfect knowledge.

It is funny that she describes effective theory as if it were just one type of a physical theory. She also studies string theory which never makes any predictions and claims to be a theory of everything. She acts as if these are just two kinds of scientific theories. No, there is one kind of scientific theory. String theory is not science.

All of the Edge essays are on this page.

Bad week for hidden variables

The Quantum Frontiers blog writes:

Today, it became abundantly clear that it’s been a tough week for hidden variable theories. ...

Let me explain. Hidden variable theories were proposed by physicists in an attempt to explain the ‘indeterminism’ which seems to arise in quantum mechanics, and especially in the double-slit experiment. ...

However, the two recent Science papers in question used quantum-information variants of this delayed-choice experiment to hammer additional nails in the coffin of local hidden variable theories.

As I explained this week about a third paper against hidden variables, these theories have been dead since 1930.

So why do physicists keep disproving hidden variable theories if no one believes in them anyway? Einstein and other quantum mechanics skeptics expressed a preference for hidden variable theories.

I argued in my FQXi essay that pursuit of hidden variable theories is rooted in a false belief in that mathematization of nature. People refuse to acknowledge that they are even making the assumption.

Minkowski conclusions independent of Einstein

Galina Weinstein writes in a new paper:

In the summer of 1905, Minkowski and Hilbert led an advanced seminar on mathematical physics, on electrodynamical theory. Minkowski told Born later that it came to him as a great shock when Einstein published his paper in which the equivalence of the different local times of observers moving relative to each other was pronounced; for he had reached the same conclusions independently. He never made a priority claim and always gave Einstein his full share in the great discovery. In his famous talk, "Space and Time" Minkowski wrote that the credit of first recognizing sharply that t and t' are to be treated the same, is of A. Einstein.

In Space and Time, Minkowski does credit Einstein for observing that local time is the local time of an electron. It is the only part of relativity that Minkowski credits to Einstein. Minkowski's wrote:

Lorentz denoted the combination t' of (t and x) as the local time (Ortszeit) of the uniformly moving electron, and used a physical construction of this idea for a better comprehension of the contraction-hypothesis. But to perceive clearly that the time of an electron is as good as the time of any other electron, i.e., that t and t' are to be treated equivalently, has been the service of A. Einstein.

This is quite similar to what Einstein had just written in his 1907 review paper:

It required only the recognition that the auxiliary quantity introduced by H. A. Lorentz, and called by him "local time", can be defined as simply "time."

Einstein seems to be taking credit for this idea, but Poincare clearly had this idea before Einstein and Minkowski. Lorentz may have had it also, as Poincare attributed it to Lorentz. Poincare even nominated Lorentz for a Nobel Prize in 1902 to recognize his idea of local time. Minkowski studied Poincare's papers in his seminar, and should have known that Poincare had the idea before Einstein. As Weinstein explains:

Scott Walter writes, "This story of Minkowski’s recollection of his encounter with Einstein’s paper on relativity is curious, in that the idea of the observable equivalence of clocks in uniform motion had been broached by Poincaré in one of the papers studied during the first session of the electron-theory seminar. It is possible, of course, that Poincaré’s operational definition of local time escaped Minkowski’s attention, or that Minkowski was thinking of an exact equivalence of timekeepers".25 Before 1905 Poincaré stressed the importance of the method of clocks and their synchronization by light signals. He gave a physical interpretation of Lorentz's local time in terms of clock synchronization by light signals, and formulated a principle of relativity. John Stachel explains: "Poincaré had interpreted the local time as that given by clocks at rest in a frame moving through the ether when synchronized as if – contrary to the basic assumptions of Newtonian kinematics – the speed of light were the same in all inertial frames. Einstein dropped the ether and the 'as if': one simply synchronized clocks by the Poincaré convention in each inertial frame and accepted that the speed of light really is the same in all inertial frames when measured with clocks so synchronized".26

Stachel has made a career out of editing Einstein's papers and finding ways to credit Einstein, and is correct about Poincare having the operational definition of local time that Minkowski credited to Einstein.

The only thing left for Stachel to credit Einstein is Poincare's aether and "as if". But Poincare's explanation did not involve the aether or an "as if". Stachel is quoting himself, not Poincare.

I did not know that Minkowski told Born that he reached some relativity conclusions independently of Einstein. But Minkowski appears to have gotten those conclusions from Poincare. His famous Space And Time paper does not mention Poincare, but his previous paper cites Poincare and directly follows him with the Lorentz group, four-dimensional spacetime, and electromagnetic covariance. So yes, Minkowski probably did come to all those conclusions independently of Einstein because he got them from Poincare.

At any rate, it was Minkowski's 1908 Space And Time article that got everyone excited about relativity and popularized the new geometrical interpretation of spacetime. Einstein's 1905 paper was considered an elaboration of Lorentz's ideas. As Weinstein documents, Minkowski wrote to Einstein in late 1907 asking for a reprint of his 1905 paper, just a couple of months before Minkowski presented his own results. So Minkowski's seminar and work were based almost entirely on Lorentz and Poincare. The supposedly original idea of the operational identification of local time had been published years earlier by Poincare.Brother HL-2270DW Laser Printer (Google Affiliate Ad)

New paper tries to disprove quantum mechanics

I commented in May on work supposedly Showing that the wavefunction is real. Now the theorists are trying experimental tests, and have posted this paper:

Can different quantum state vectors correspond to the same physical state? An experimental test

A century on from the development of quantum theory, the interpretation of a quantum state is still discussed. If a physicist claims to have produced a system with a particular wave function, does this represent directly a physical wave of some kind, or is the wave function merely a summary of knowledge, or information, about the system? A recent no-go theorem shows that models in which the wave function is not physical, but corresponds only to an experimenter's information about a hypothetical real state of the system, must make different predictions from quantum theory when a certain test is carried out. Here we report on an experimental implementation using trapped ions. Within experimental error, the results confirm quantum theory. We analyse which kinds of theories are ruled out. ...

The result of Ref. [3] can be considered as a no-go the-orem for interpretations of quantum theory, analogous to Bell's theorem. Each theorem states that a certain class of theories must make different predictions from quan-tum theory -- locally causal theories in the case of Bell's theorem and ψ-epistemic theories in the case of Ref. [3]. We have suggested that a natural threshold is defined by quantum state discrimination.

So they are claiming that they have disproved ψ-epistemic theories, just as Bell and Bell test experiments have disproved locally causal theories.

No, Bell did not disprove locally causal theories. He only disproved a type of hidden variable theories that no one believed anyway. Likewise, these guys are only trying to disprove ψ-epistemic theories that no one believes. I explain further here and here.

Quantum mechanics was discovered in the 1920s, and incorporated into physics textbooks in the 1930s. Ever since, the mainstream interpretation has been that it is a locally causal theory and a ψ-epistemic theory. So why are all these physicists, 80 years later, trying to do experiments that prove quantum mechanics correct but also disprove local causality and ψ-epistemic ontology?

Maybe this paper has some clever new way of testing quantum mechanics. I don't know. But it is not telling us anything except what was common knowledge 80 years ago.

I will be interested to see whether this paper gets publicized as some profound new result, and if the editors require that the claims be scaled back before publication. If I were the referee, I would require that the article say that it was only confirming what Bohr, Heisenberg, and the textbooks said 80 years ago. I doubt that the editor will require any such change.

Aether dominates accepted physics

Canon T3i 18.0MP Digital SLR Camera with 18-55mm IS Lens - Digital (Google Affiliate Ad)The Wikipedia article on the Relativity priority dispute says:

But they [most historians of science like Holton] argue that it was Einstein who completely eliminated the classical ether ...

Yes, most historians like Holton say that, but it is also directly contrary to what other reputable sources say. For example, a very prominent physicist says:

“Quite undeservedly, the ether has acquired a bad name. There is a myth repeated in many popular presentations and textbooks, that Albert Einstein swept it into the dustbin of history. The real story is more complicated and interesting. I argue here that the truth is more nearly the opposite: Einstein first purified, and then enthroned, the ether concept. As the 20th century has progressed, its role in fundamental physics has only expanded. At present, renamed and thinly disguised, it dominates the accepted laws of physics.” [Fantastic Realities: 49 Mind Journeys And a Trip to Stockholm, By Frank Wilczek, Betsy Devine, 2006, p.293]

Yes, Wilczek is correct. Yes, the aether is essential to modern theories of electromagnetism. The biggest physics news of the 21st century is the discovery of the Higgs boson, and that was the confirmation of a 50 year old aether theory.

It is crazy to talk of eliminating the aether as if that were some great accomplishment. Explaining the failure to detect aether velocity led to the theory of relativity, but Einstein himself said that it was a mistake to deny the aether. The aether (under various names) is essential to modern physics.

Explaining quantum weirdness

Johannes Koelman explains some quantum paradox with analogies, and then gives a choice of interpretations of the weirdness:

1) Deny Its Existence
2) Accept Non-Local Socks
3) Embrace Precognition
4) Deny Free Will
5) Avoid The "Would Have Happened If" Fallacy

He takes the last one, of course. It is the positivist view that Bohr advocated all along. The other views cannot be ruled out, but they are pretty crazy.

Most explanations of quantum mechanics are filled with nonsense. For example, the latest Scientific American says:

Throughout the 20th century scientists and mathematicians have had to accept that some things will always remain beyond the grasp of reason. In the 1930s Kurt Gödel famously showed that even in the rational universe of mathematics, for every paradox that deep thinking slaps down, new ones pop up. Economists and political theorists found similar limitations to rational rules for organizing society, and historians of science punctured the belief that scientific disputes are resolved purely by facts. The ultimate limits on reason come from quantum physics, which says that some things just happen and you can never know why. ...

Quantum mechanics may be a better model for human behavior than classical logic, which fails to predict the human impulse to cooperate and act altruistically. Instead of trying to force our thinking into a rational framework, we are better off expanding the framework.

No, Goedel and economists did not show that. The claim about "historians of science" seems to be a reference to Kuhnian paradigm shifts. That is where philosophers say that physicists are irrational.

Meeting on naturalism

A bunch of atheist intellectuals just had an informal discussion meeting, and a philosopher noted:

Coyne declared himself to be an incompatibilist (no surprise there), accusing compatibilists of conveniently redefining free will in order to keep people from behaving like beasts. However, Jerry himself admitted to having changed his definition of free will, and I think in an interesting direction. His old definition was the standard idea that if the tape of the history of the universe were to be played again you would somehow be able to make a different decision, which would violate physical determinism. Then he realized that quantum indeterminacy could, in principle, bring in indeterminism, and could even affect your conscious choices (through quantum effects percolating up to the macroscopic level). So he redefined free will as the idea that you are able to make decisions independently of your genes, your environments and their interactions. To which Dennett objected that that’s a pretty strange definition of free will, which no serious compatibilist philosopher would subscribe to. ...

During the follow-up discussion Weinberg declared his leaning toward Dennett’s position, despite his (Weinberg’s) acceptance of determinism.

This shows the confusion caused by physical determinism.

I say that determinism is absurd, and that so are Coyne's consequences. I am surprised to see the famous Steven Weinberg in the determinist camp, because most physicists believe that quantum mechanics proves that the world is fundamentally probabilistic and non-deterministic.

I am not advocating non-determinism either. There is no scientific evidence one way or the other. The main argument for non-determinism is quantum mechanics, but that is no more probabilistic than any other scientific theory.

These intellectuals move on to free will, morality, God, and various other issues. Needless to say, their foolish conclusions are even sillier than their faulty premises.