Wednesday, October 21, 2020

Dr. Bee on Bohmian pilot wave theory

I posted a criticism of a new movie on David Bohm and pilot wave theory. Unfortunately, it has now been taken down, as the producers are using it for fundraising.

Now Dr. Bee has posted a more detailed criticism of the theory.

One of the big disadvantages of Bohmian mechanics, that Einstein in particular disliked, is that it is even more non-local than quantum mechanics already is. That’s because the guiding field depends on all the particles you want to measure. This means, if you have a system of entangled particles, then the guiding equation says the velocity of one particle depends on the velocity of the other particles, regardless of how far away they are from each other. ...

[Reader:] The argument against Bohmian mechanics is that it is non-local, and QFT requires locality. But didn't Bell prove that the universe is non-local (for most physicists at least; I realize you have an alternative explanation for his results)?

[Sabine Hossenfelder:] First, you cannot use a mathematical theorem to prove how the universe is. What Bell proved is that theories of a certain type obey an inequality. Experiment shows that this inequality is violated. It follows that one of the assumptions of Bell's theorem must be violated.

A violation of one of these assumptions is qua definition what people in quantum foundations call "non-locality". It is an extremely misleading use of the word and has nothing to do with that particle physicists call "non-locality" which refers to non-local interactions.

These two different types of non-locality have caused so much confusion I really think we should stop referring to quantum mechanics as "non-local". Some have suggested to instead use the term "non-separable" which makes much more sense indeed.

In any case, Bohmian mechanics violates Bell's inequality and is thus non-local in Bell's sense. This is fine and not the problem I was talking about. The problem is that the ontology of Bohmian mechanics is non-local in the QFT sense (as I explained in the video). This is not necessarily a problem, but certainly one of the reasons why it's been hard to make a QFT out of it. The other problem is Lorenz-invariance (which I refer to as the "speed of light limit).

This is an important point.

Bell nonlocality is an abuse of terminology that only confuses people. Bohm's theory is truly nonlocal in a way that no scientific theory is. It is a fringe theory that no one has found useful for anything.

Sometimes someone claims that Bohm's theory is more intuitive, but that is nonsense. The nonlocality makes it more counter-intuitive than any other textbook theory.

When she said the "historical context is relevant", I thought that she was going to tell us that Bohm was a Commie. It is funny how he has a cult following. There is some weird ideology driving support for his theory, but even after watching the movie, I cannot figure out what it is.

Another comment:

Bohm's theory is convinient for quantum cosmology, since it avoids the problem of the system and the observer which are necessary in the Copenhagen interpretation so that the Copenhagen interpretation cannot be applied to the whole universe.
The theory is nonlocal, so events in one galaxy can depend on subtleties in another galaxy. And that is supposed to be convenient for cosmology? I doubt that it has ever been of any use to cosmology.

Monday, October 19, 2020

First prize to a mathematical physicist

Giving the Nobel prize to Roger Penrose is striking because it is so rare that the prize has gone to the mathematical physicist. He might be the only one, altho an argument could be made that Wigner and 'tHooft were also examples.

You are probably thinking that there have been lots for prizes for theoretical physicists, such as Einstein, Dirac, Pauli, Feynman, etc. And they all use heavy mathematics.

But not really. There is a big difference between theoretical physicists and mathematical physicists.

Wikipedia explains:

The term "mathematical physics" is sometimes used to denote research aimed at studying and solving problems in physics or thought experiments within a mathematically rigorous framework. In this sense, mathematical physics covers a very broad academic realm distinguished only by the blending of some mathematical aspect and physics theoretical aspect. Although related to theoretical physics,[3] mathematical physics in this sense emphasizes the mathematical rigour of the similar type as found in mathematics.

On the other hand, theoretical physics emphasizes the links to observations and experimental physics, which often requires theoretical physicists (and mathematical physicists in the more general sense) to use heuristic, intuitive, and approximate arguments.[4] Such arguments are not considered rigorous by mathematicians, but that is changing over time.

Penrose's work is squarely within mathematical physics.

Nobel prizes were not given for this before. For example, a prize was not given for CPT symmetry, even tho it is considered a fundamental theorem.

Articles about this year's prize raise the related question -- why give a relativity prize to Penrose when Einstein did not get prize for relativity?

For example:

Even when an award goes to the right person, it may be for the wrong -- or at least arguable -- reasons. Such is the case with Albert Einstein, whose 1921 physics Nobel was bestowed not for the theory of relativity but for his work on the photoelectric effect.
That article describes dubious prizes given for inventing poison gas and the lobotomy.

But Einstein was still not a mathematical physicist. The essence of Penrose's prize-winning contribution was a mathematical proof, but no one would say that about Einstein's contributions.

In the case of special relativity, Einstein's contribution is not considered mathematical because all those math formulas had been published already by others. Those who credit him credit him for a metaphysical view, as the math was not new, and the physical consequences were not either. The Nobel committee does not give prizes for metaphysical views.

Perhaps Einstein could have gotten one for general relativity, and it might have been shared with Grossmann and Hilbert. Maybe the committee had trouble assessing what Einstein really did, since he hid his sources so well.

Another comment from a biology professor:

Darwin’s theory is, like Einstein’s, amazing because of its sui generis character — because it didn’t involve much standing on the shoulders of giants who came before. And that is why we celebrate Darwin (and, to a lesser extent, Wallace), and don’t hail Arabic scholars as unrecognized harbingers of evolutionary theory.
I don't get this at all. Einstein's work depended very heavily on earlier work. So did Darwin's, and Darwin acknowledges it.

Friday, October 16, 2020

Another journal endorses Joe Biden

The British journal Nature, maybe the top science journal in the world, editorializes:
On 9 November 2016, the world awoke to an unexpected result: Donald Trump had been elected president of the United States.

This journal did not hide its disappointment. ...

Trump claims to put ‘America First’.

There is the heart of the gripe -- a bunch of non-Americans complaining that the American President puts America first.

Getting to more specific gripes:

In the pandemic’s earliest days, Trump chose not to craft a comprehensive national strategy to increase testing and contact tracing, and to bolster public-health facilities. Instead, he flouted and publicly derided the science-based health guidelines set by the US Centers for Disease Control and Prevention (CDC) for the use of face masks and social distancing.
No, the CDC told us repeatedly that face masks were useless, and not to wear them.
With the nation’s death toll now exceeding 215,000, the coronavirus has killed more people in the United States than anywhere else.
The coronavirus is listed as the cause of death in only 6% of these. The rest had other comorbidities.
No president in recent history has tried to politicize government agencies and purge them of scientific expertise on the scale undertaken by this one.
Not even one example of a scientist fired.
Trump has also promoted nationalism, isolationism and xenophobia — including tacitly supporting white-supremacist groups. ...

The United States’ reputation as an open and welcoming country to the world’s students and researchers has suffered.

Now we are getting to the real gripes.
Joe Biden, by contrast, has a history in the Senate as a politician who has reached across to his political opponents and worked with them to achieve bipartisan support for legislation
His best-known examples are the Crime Bill, which he now disavows, and the Iraq War, which no one wants to talk about.
He has pledged that decisions on the pandemic response will be made by public-health professionals and not by politicians; and he is rightly committing to restoring the ability of these professionals to communicate directly with the public.
Trump regularly put Fauci and other "public-health professionals" on TV. But yes, the decisions were made by elected officials.

It is sad how these scientific journals have been politicized. I am not sure I will ever trust them again.

It would be one thing if the President said things which were scientifically false, or fired scientists and replaced them with astrologers, or somehow sabotaged scientific works. But nothing like that is even alleged. He has funded the most worthy scientific projects, and promoted science. In his handling of COVID-19, he was open, transparent, and following the advice of the best experts. No one can explain how he could have done any better.

This is all political, and it has very little to do with science. Trump is hated for other reasons.

Update: Other Nature articles are political, such this recent obituary of Ruth Bader Ginsburg. It is not clear why a science journal would publish an obituary of a judge in another country. The only specific opinion of hers mentioned was her very-partisan dissent in favor of recounts that were thought to favor Gore in the 2000 election.

Thursday, October 15, 2020

Kid thinks that Earth is on fire

SciAm opinion column:
I’ve never known an Earth that wasn’t on fire.

I’m 23 years old, and I’m not alone. My entire generation has come of age in a world so defined by climate change and human destruction — by forests burning and glaciers melting, by extinguished species and rising seas — that it’s sometimes been hard to fathom what an even more dismal future might look like.

That is, until the pandemic reared its ugly head, bringing about the kind of worldwide lockdowns and upheavals of daily life that have given terrifying prescience to the term “global emergency” while still falling far short of what scientists say will be the worst environmental catastrophes that await us. The fate of nature, like so much else, has been an agonizing side-story to the virus — a real-time plot that is being followed most closely, I think, by those of us young enough to one day see the worst of it. ...

Here in the U.S., though, the chorus is louder now than it’s ever been—as some of the worst wildfires on record tear through the American West, painting the sky orange, and as hurricanes ravage the South, leaving behind apocalyptic fields of ruin. In today’s pandemic moment, nature’s storyline has reached a low point.

I could not bear to finish reading this nonsense.

This kid should ask his grandparents about life during World War II. And maybe they could relay stories from their grandparents about famine, disease, and the lack of what we consider today to be basic necessities, such as clean water and electricity.

How did we get such a generation of miserable spoiled brats?

Tuesday, October 13, 2020

Dr. Bee says diff-eqs imply determinism

Sabine Hossenfelder is a superdeterminism, and she made a new video saying that the concept of free will makes no sense:
But first, let me tell you what’s wrong with this intuitive idea that we can somehow select among possible futures.

Last week, I explained what differential equations are, and that all laws of nature which we currently know work with those differential equations. These laws have the common property that if you have an initial condition at one moment in time, for example the exact details of the particles in your brain and all your brain’s inputs, then you can calculate what happens at any other moment in time from those initial conditions. This means in a nutshell that the whole story of the universe in every single detail was determined already at the big bang. We are just watching it play out.

These deterministic laws of nature apply to you and your brain because you are made of particles, and what happens with you is a consequence of what happens with those particles.

She makes it clear that she is no relying on neuroscience or any other scientific knowledge. She also explicitly rejects philosophical rationalizations of free will, like compatibilism.

In other words, she is a full believer in Laplace's Demon.

Free will is mostly a philosophical question. Superdeterminism cannot be disproven, just as the simulation hypothesis cannot be.

So I am criticizing her reasoning, more than her conclusion.

First, the brain is not made of particles. It is made of quantum fields.

2nd, differential equations are only approximations, and do not predict peoples' choices.

3rd, differential equations are often used with stochastic processes, and are not determinist.

I can predict that some people who didn’t actually watch this video will leave a comment saying they had no other choice than leaving their comment and think they are terribly original.
Ha, ha, but she did not leave the post open for comments, so her prediction turned out wrong.

Here is my biggest disagreement:

What about quantum mechanics? In quantum mechanics some events are truly random and cannot be predicted. Does this mean that quantum mechanics is where you can find free will? Sorry, but no, this makes no sense. These random events in quantum mechanics are not influenced by you, regardless of exactly what you mean by “you”, because they are not influenced by anything. That’s the whole point of saying they are fundamentally random. Nothing determines their outcome. There is no “will” in this. Not yours and not anybody else’s. Taken together we therefore have determinism with the occasional, random quantum jump, and no combination of these two types of laws allows for anything resembling this intuitive idea that we can somehow choose which possible future becomes real. The reason this idea of free will turns out to be incompatible with the laws of nature is that it never made sense in the first place. You see, that thing you call “free will” should in some sense allow you to choose what you want. But then it’s either determined by what you want, in which case it’s not free, or it’s not determined, in which case it’s not a will.
No, this is completely wrong. Random just means that it is not predicted by the available data and theory. It says nothing about whether something else might be determining the outcome.

If I have a Schroedinger cat in a box, then it appears random to me whether the cat is alive or dead. But someone else may have peeked, and know the answer. The randomness just applies to my knowledge. Likewise, your decision making may seem random to me, because I cannot predict it, but to you it is driven by your free will.

She seems to have some very strange idea about what "fundamentally random" means. It does not mean that there can be no free will involved. There has never been any scientific work to support that.

That being said, a lot of people are brainwashed, or otherwise fail to show much free will. There is even evidence that drugs can be used to alter political beliefs:

Increased nature relatedness and decreased authoritarian political views after psilocybin for treatment-resistant depression ...

This pilot study suggests that psilocybin with psychological support might produce lasting changes in attitudes and beliefs. Although it would be premature to infer causality from this small study, the possibility of drug-induced changes in belief systems seems sufficiently intriguing and timely to deserve further investigation.

The way the entire academic establishment has lined up politically this year, leads me to believe that they do not have free will.

Update: Scott Aaronson says it doesn't matter if we are living in a simulation, as we would not know. I do think that believing the world is a simulation, or a dream, or a superdetermined scenario, are all about the same belief. They are all just denying reality and pretending that everything is some sort of fiction.

Monday, October 12, 2020

Superdeterminism forbids human free will

A new paper promotes superdeterminism:
The violation of Bell inequalities seems to establish an important fact about the world: that it is non-local. However, this result relies on the assumption of the statistical independence of the measurement settings with respect to potential past events that might have determined them. Superdeterminism refers to the view that a local, and determinist, account of Bell inequalities violations is possible, by rejecting this assumption of statistical independence. ...

However, most physicists do not seriously consider superdeterministic theories as interpre-tations of Bell inequalities — although, importantly, they often the superdeterminist loophole cannot, as a matter of principle, be closed. ...

But Bell goes further and claims that free will could not exist in a superdetermin-istic world. He suggest that the experimenters’ capacity to freely choose the measurement settings comes under attack when operating in the background of a superdeterministic theory. Superdeterminism is hence characterised as an ‘absolute determinism in the universe’, equated with a ‘complete absence of free will’.

The paper goes on to argue that other determinists have ways of explaining away free will, so superdeterminists should be able to do so similarly.

Superdeterminism really is incompatible with free will. If you believe in superdeterminism, you have to believe that when an experimenter turns the dials on his apparatus, his choices are constrained by a need for an outcome that was predetermined 14 billion years ago.

The error in this paper is right at the beginning, where it says that Bell proved that the world is either super-deterministic or non-local. The more sensible conclusion is that the world is governed by local quantum field theory, and that humans have free will. The world has stochastic aspects whether human choices are involved or not.

I don't know how anyone can believe in super-determinism, and believe in the scientific method at all. It would all hypothesis testing is just an illusion.

Saturday, October 10, 2020

More leftist academics endorse Biden

The NY Times reports:
Throughout its 208-year history, The New England Journal of Medicine has remained staunchly nonpartisan. The world’s most prestigious medical journal has never supported or condemned a political candidate.

Until now.

In an editorial signed by 34 editors who are United States citizens (one editor is not) and published on Wednesday, the journal said the Trump administration had responded so poorly to the coronavirus pandemic that they “have taken a crisis and turned it into a tragedy.”

The journal did not explicitly endorse Joseph R. Biden Jr., the Democratic nominee, but that was the only possible inference, other scientists noted.

The editor in chief, Dr. Eric Rubin, said the scathing editorial was one of only four in the journal’s history that were signed by all of the editors. The N.E.J.M.’s editors join those of another influential publication, Scientific American, who last month endorsed Mr. Biden, the former vice president.

This is from the journal that had to retract a high-profile Covid-19 study because the data in it were so obviously bogus.

This is transparently political, as they don't even attempt to explain how Biden is going to do any better.

The SciAm editors are doubling down with another political rant:

Instead of thinking about whether to vote Democratic or Republican in the upcoming U.S. election, think about voting to protect science instead of destroying it.

As president, Donald Trump’s abuse of science has been wanton and dangerous. It has also been well documented. ...

Alarmingly, many of the attacks involve the most immediate and long-term threats to people on earth: the COVID-19 pandemic and climate change. In September, for example, Politico reported that Trump’s political appointees in the Department of Health and Human Services were editing weekly reports from the Centers for Disease Control and Prevention (CDC) about the pandemic prior to publication. Ten days later, U.S. Secretary of Energy Dan Brouillette asserted that “no one knows” whether human activities are causing climate change — a refrain that is so tired it has become silly.

I looked up the guy's quote, and here is what he actually said:
Scientists say a lot of things. I have scientists inside of the Department of Energy that say a lot of things. Look, the bottom line is we live here, so we must have some impact. The question is, what is the exact impact that we’re having? And that’s the question that has not been resolved.
None of the arguments in NEJM or SciAm hold any water. I would think that these journals would be run by smart guys, but they cannot find any example of any harm that Pres. Trump has done.

Friday, October 9, 2020

Arguing that the Universe is pure Math

Economics professor Steve Landsburg has a good lecture arguing for Max Tegmark's notion of mathematical universes. I posted several times on Tegmark's book, when it came out a few years ago.

At 34:00, he describes mathematical truth.
At 35:00, he describes mathematical Platonism.
At 40:30, he says physical theories are approximations to truth.

I can accept all of that, but then at 40:50 he says:
"The one hypothesis that underlies every viable physical theory is that the Universe is a mathematical object."

Here is where I differ. I don't think that our Universe is a mathematical object, or that any of our theories assume that it is. Our physical theories are mathematical approximations to a non=mathematical object.

This puts me at the opposite extreme from Tegmark's hypothesis. While he says all mathematical objects are universes, I say that none of them are.

My skepticism is based primarily based on:

(1) All of the interesting mathematical statements are about infinities, but there are no infinities in the physical universe.

(2) We don’t really even have any candidate for the Universe as a mathematical object. There are those who talk about having a quantum wave function of the Universe, but they end up talking about many-worlds and other ideas that have never made any sense or had any predictive value.

(3) Attempts to realize the world as a mathematical object are what led Bell to believe in local hidden variables. We now know that local hidden variables are impossible, so maybe the assumptions that led to that belief are also wrong.

Penrose has given lots of interviews, and will probably give some more now that he is a big-shot Nobel prize winner. I don't remember him giving an opinion on this issue, but it is possible. He is as close to being an authority on this as anyone.

Wednesday, October 7, 2020

Roger Penrose wins Nobel Prize

I am surprised that Roger Penrose won the Nobel Prize in Physics, for his mathematical physics of black holes. People always said that Hawking would not get a Nobel because his work was too theoretical, but Penrose's is more so.

I cannot think of any other mathematician to get a Nobel. The closest I can think of is Eugene Wigner, who did foundational work on group representations in quantum mechanics.

Perhaps they were eager to give another black hole prize, or to have another female co-winner, I don't know.

Usually prizes are not given to astronomers either. Last year, Peebles shared a prize for some theoretical cosmology work. Maybe that was a signal that attitudes have shifted.

I do think that Penrose's contributions to physics are much greater than most of the Nobel prizes. Congratulations to him.

Most of the articles about this year's prize talk about Einstein a lot, even tho:

“Einstein did not himself believe that black holes really exist, these super-heavyweight monsters that capture everything that enters them,” the Nobel Committee said. “Nothing can escape, not even light.”
Karl Schwarzschild discovered the black hole equations in 1916. It appears that it was not understood mathematically until decades later. That is, only later did they figure that there was an event horizon dividing the interior from the exterion, and that there was no metric singularity there.

After a few more decades, astronomical evidence of black holes was found, and now gravititational waves from collisions have been observed. A Nobel was given for that in 2017, so now 3 of the last 4 years have had Nobels going to cosmologists and astronomers.

Update: Here is the Nobel citation, which nicely explains the history of work related to this year's prize. A footnote makes reference to Einstein not getting the prize for general relativity. It is ambiguous whether Hawking would have gotten a share, had he still been alive. It does credit Penrose with first changing physicist thinking about black holes.

Monday, October 5, 2020

Gerber had Mercury formula before Einstein

People often give Albert Einstein credit for General Relativity because he deduced the big consequences -- deflection of starlight, precession of Mercury's orbit, and redshift of light from moving stars. Maybe also gravitational waves, black holes, and the big bang, but those were mostly done by others.

Paul Gerber published in 1898 and 1902 a theory for the precession of Mercury's orbit, including this formula:

Ψ = 24 π3 a2 / (τ2 c2 (1 - ε2))
This is identical to what Einstein published in 1915. The difference is that Einstein based it on relativity, and Gerber just assumed that the speed of gravity was the same as the speed of light.

It is considered a consequence of relativity that gravity propagates at the speed of light, and since Gerber did not know relativity, he must have made some other hidden assumptions.

Here is Einstein's 1920 repudiation:

Mr. Gehrcke wants to make us believe that the perihelion shift of Mercury can be explained without the theory of relativity. So there are two possibilities. Either you invent special interplanetary masses. [...] Or you rely on a work by Gerber, who already gave the right formula for the perihelion shift of Mercury before me. The experts are not only in agreement that Gerber’s derivation is wrong through and through, but the formula cannot be obtained as a consequence of the main assumption made by Gerber. Mr. Gerber’s work is therefore completely useless, an unsuccessful and erroneous theoretical attempt. I maintain that the theory of general relativity has provided the first real explanation of the perihelion motion of Mercury. I did not mention the work by Gerber initially, because I did not know about it when I wrote my work on the perihelion motion of Mercury; even if I had been aware of it, I would not have had any reason to mention it.
Einstein is famous for not citing prior work, and here we see him defending the practice. He says that he would not cite Gerber's correct formula, because his derivation was not a real explanation.

So maybe this is why he didn't cite Lorentz or Poincare or Hilbert or others whose work he plagiarized. He was claiming priority for the first real explanation, and did not want to dilute that with an acknowledgement of prior work.