Monday, June 17, 2024

Epicycles are Real

A reader cites Carl Sagan's 1980 Cosmos a personal journey Ep. 3. Harmony of the Worlds (video, transcript).
This little machine shows Ptolemy’s model. The planets were imagined to go around the Earth, attached to perfect crystal spheres — but not attached directly to the spheres, but indirectly, through a kind of off-center wheel. The sphere turns, the little wheel rotates, and — as seen from the Earth — Mars does its loop-the-loop. This model permitted reasonably accurate predictions of planetary motion: where a planet would be on a given day. Certainly good enough predictions for the precision of measurement in Ptolemy’s time and much later. Supported by the church through the Dark Ages, Ptolemy’s model effectively prevented the advance of astronomy for 1,500 years.

Finally, in 1543, a quite different explanation of the apparent motion of the planets was published by a Polish cleric named Nicolaus Copernicus. Its most daring feature was the proposition that the sun, not the Earth, was the center of the universe. The Earth was demoted to just one of the planets. The retrograde (or loop-the-loop) motion happens as the Earth overtakes Mars in its orbit. You can see that, from the standpoint of the Earth, Mars is now going slightly backwards and now it is going in its original direction. This Copernican model worked at least as well as Ptolemy’s crystal spheres, but it annoyed an awful lot of people. The Catholic Church later put Copernicus’s work on its list of forbidden books.

So Ptolemy developed a reasonably accurate model, but it was somehow used by the Catholic Church to keep everyone in the Dark Ages?

No, this is mostly nonsense. The Church only objected to nine sentences in the Copernicus book, and not to publication of the model. Ptolemy did not require crystal spheres.

The Wikipedia article on epicycles is much more sensible:

Epicycles worked very well and were highly accurate, because, as Fourier analysis later showed, any smooth curve can be approximated to arbitrary accuracy with a sufficient number of epicycles. However, they fell out of favor with the discovery that planetary motions were largely elliptical from a heliocentric frame of reference, which led to the discovery that gravity obeying a simple inverse square law could better explain all planetary motions.
The first Ptolemy epicycle for each planet is the orbit of the Earth, and is used to explain the retrograde modtion. People can argue that this epicycle is not real, because Mars never really goes backwards. But Mars does go backwards, as viewed from the Earth, and that is what Ptolemy was modeling.

Subsequent epicycles were used to model variations in speed and direction from uniform circular motion. The Copernicus model did not need the first epicycle, as the Earth had its own orbit, but needed the subseqent epicycles, as deviations from uniform circular motion was observable at the time.

As Sagan later explained, Tycho Brahe made the observations that enabled models superior to Ptolemy's. Astronomy was not held back by epicycles, but by a lack of more precise data. That data came from Tycho, and later the invention of the telescope

Sagan pushes his anti-religion beliefs, but all these advances took places in Christendom, and not elsewhere.

Tuesday, June 11, 2024

Situational Awareness

The AI world is buzzing with the predictions of Leopold Aschenbrenner. It has some overlap with the AI doomsayers who say AGI superintelligence will take over the world, except that he has inside knowledge from OpenAI, and he has specific arguments how it is all going to happen in the next five years.

Scott Aaronson raves about the analysis.

Interestingly, Aschenbrenner sees his fellow AI researchers as being among the first to be put out of work by the new superintelligence. There is a global arms race to create the best AI, and by 2030, the winner will be doing its own research to improve itself. No humans needed, except to keep mounting Nvidia computers into server farms.

Update: Sabine Hossenfelder posts her critique. She agrees with some of it, but gets off the bus with the wild predictions of scientific progress.

Monday, June 10, 2024

Carroll tries to defend Many-Worlds again

Physicis Sean M. Carroll tries to answer this question:
Joel remok says if we can't access any of the many worlds, what 2:31:07 is the purpose of studying it, when there are still many discoveries to be investigated in the reality we exist in?
Good question. There is no point in talking about parallel worlds that we can never see or know anthing about.

The transcript of his answer:

2:31:13 look I've said before I don't care about the other worlds I care about the laws of physics the question is we have 2:31:20 problems with quantum mechanics as it is taught it is not a sensible rigorous coherent Theory. we make things up like 2:31:28 observations and wave function collapse that aren't rigorously defined. many worlds is a well-defined theory that 2:31:37 replaces the ill defined Copenhagen interpretation and lets us actually do science with it. the point of many worlds 2:31:44 is not the other worlds. it's that we've answered the question of what is a measurement, why do you get probability, 2:31:50 and things like that, and equally importantly there's the fact that we don't know the fundamental laws of 2:31:56 physics. we're not done with physics yet we're trying to build better laws of physics and I strongly think that taking 2:32:02 quantum mechanics seriously and thinking about what is the correct foundational version of quantum mechanics will be 2:32:09 useful to that program. so again it's not about the worlds. people who really 2:32:15 obsess about the other worlds are the ones who haven't really internalized many world worlds many worlds is just 2:32:22 it's always obeying the Sher equation that's the essence of the theory
No, this is nonsense on every level.

Many-worlds does not answer the question of what is a measurement. It says that a measurement splits the worlds, but there is no explanation of how the worlds split, how many worlds there are, how you knowt he worlds have split, or anything. It is no better than how bohr explained it.

Many-words says nothing about how we get probabilities. The many-worlds folks do not even believe in probabilities.

Saying that Copenhagen is ill-defined to do science is backwards. Copenhagen has had successes worth trillions of dollars. No one has ever done any science with many-worlds.

I don't know how Carroll says this junk with a straight face. It is like saying Astrology is the only true science.

Here is the distinction. Copenhagen says you can predict an experiment, with probabilities for different outcomes. Once you observet the outcome, you discard the other possibilites as events that did not happen.

Many-worlds is just like that, except that there are no probabilities for the outcomes, because they all happen, and no world is any more likely than any other. Once you see an outcome, the parallel worlds with the other outcomes go out of reach. A prediction might seem true or false, but that is only because you are trapped on one of the worlds. It is not possible to do any science, because no prediction can ever be falsified.

Copenhagen makes sense and is scientific. Many-worlds is an unscientific fantasy.

Saturday, June 8, 2024

AI Models will maintain String Research

Peter Woit reports that the top string theorists are retiring, and they are worried that the younger generation will not carry on as before.

Not to worry! One suggests that AI large language models like ChatGPT will come to the rescue, because they can

train an LLM with the very best papers written by the founding members, so that it can continue to set the trend of the community.
Okay, maybe this was a joke, but it is likely to happen anyway. We may have reached peak knowledge. Already journals are being tricked into publishing AI-generated articles. The LLMs of the future will be trained on the LLMs of the past.

There is no experimental data that has any bearing on string research. Ed Witten cannot live forever. Advanced AI LLMs may be able to carry on string papers indefinitely.

Wednesday, June 5, 2024

SciAm gets Trump Derangement Syndrome

Scientific American used to be the worlds greatest popular science magazine, but now it is filled with politics and pseudoscience.

Now it has this article from an Australian Politics professor:

Donald Trump is now leading in many polls and could retake the U.S. presidency, despite numerous scandals, indictments and erratic behavior. Explanations for his popularity focus on factors like white identity, right-wing authoritarianism, nationalism and populism.

U.S. politics has included people with these predilections for many decades, however, so the puzzle of Trump’s appeal remains. ...

We differentiated the most loyal Trump supporters from the rest of the American population, including those who merely voted for Trump and supported his policies, by measuring three aspects of Trump support: unquestioning credulity, exemplified by the belief that he was in fact the legitimate winner of the 2020 election; ...

Most strikingly, we find they are highly conscientious, a measure of self-reported characteristics including carefulness, dependability, orderliness and self-discipline. Conscientiousness is significantly associated with all the three cultlike aspects of Trump support.

Support for Pres. Trump is not so tricky to explain. Pres. Biden is one of the worst Presidents ever. He is responsible for foreign policy disasters in Afghanistan, Ukraine, and Gaza. His reckless spending has caused high inflation. He has allowed the USA to be invaded by millions of foreigners. He is too senile to do the job. His VP is even worse. He has pursued bogus prosecutions of his political enemics. He appoints incompetent leftist minorities. He supports the sexual mutilation of children.

Pres. Trump, on the other hand, presided over four years of peace and prosperity. He would have been re-elected, but for changed voting rules that allowed the collection of million of votes whose casting and counting could not be verified. Trump won a majority of the votes cast and counted on Election Day.

This professor even found that most Trump supporters had conscientiously examined the evidence, and found Trump to be the better man. But this article makes no mention of all the objective reasons for concluding that Trump was a better President than Biden. He blames authoritarianism, while Biden is much more authoritarian then Biden.

As an example, those who resisted covid vaccine mandates nearly all support Trump over Biden. This shows that Biden is the authoritarian, and his supporters like his authoritarianism. Also, only an auhoritarian would prosecute his political enemies.

The Scientific American of a few years ago would never have published such a trashy partisan and illogical article.

Thursday, May 30, 2024

History on Many Worlds Theory

This new paper gives some history and arguments in favor of many-worlds:
Revolutionizing Quantum Mechanics: The Birth and Evolution of the Many-Worlds Interpretation

Arnub Ghosh

The Many-worlds Interpretation (MWI) of quantum mechanics has captivated physicists and philosophers alike since its inception in the mid-20th century. This paper explores the historical roots, evolution, and implications of the MWI within the context of quantum theory. ...

In reflecting on the significance of studying the historical development of quantum interpretations, it becomes evident that the MWI represents more than just a theoretical framework—it embodies a paradigm shift in our understanding of the quantum world and its implications for the nature of reality. ... Moving forward, further research and exploration in this area hold immense potential for advancing our knowledge of quantum mechanics and its applications.

Okay, you know it is garbage when it pushes revolutions and paradigm shifts, but cannot find any actual utility to the theory.

A big problem is probability:

Moreover, the MWI has led to new insights into the nature of probability in quantum mechanics. In the MWI, probabilities arise from the relative frequencies of different outcomes across multiple branches of the multiverse, rather than from inherent randomness or observer-dependent collapses of the wavefunction. This perspective offers a coherent and objective interpretation of probability in quantum mechanics, resolving longstanding debates about the nature of quantum uncertainty. ...

Furthermore, the MWI has implications for our understanding of probability and randomness. In the MWI, probabilities arise from the relative frequencies of different outcomes across multiple branches of the multiverse, rather than from inherent randomness or observer-dependent collapses of the wavefunction. This perspective offers a coherent and objective interpretation of probability in quantum mechanics, resolving longstanding debates about the nature of quantum uncertainty. However, it also challenges traditional views of probability as a measure of uncertainty or ignorance, suggesting that probabilities are ontologically real and arise from the fundamental structure of the multiverse.

(This is repetitive.) Yes, you might think that MWI gets probabilities from comparing outcomes across branches, but no one has ever gotten this to work. It is a myth. You cannot count the branches, or calculate probabilities of outcomes, or do anything objectively. It is all a big sham.

The people who pursue many-worlds do not even believe in probabilities. If pressed, they will admit that some things seem more probable than others, but they say it is all an illusion. Some subscribe to crazy arguments that Born's rule seems more natural than other rules, but they have no good explanation for why probability works at all.

If the weather man says there is an 80% chance of rain tomorrow, then he means that his data has resulted in rain 80% of the time in the past. Once it rains, you can discard the possibility of a sunny day.

But the MWI fans reject this. They refuse to say that it will rain in 80% of the branches. And if it does rain, they refuse to reject the sunny day, because they argue that it is sunny in another part of the wave function.

Go ahead and read the article, and tell me if you find one reason to accept that MWI nonsense.

Monday, May 27, 2024

Free Will in the Block Universe

Some say that there is no free will because of the way relativity uses time as the fourth dimension.

The philsophical questions about free will go back to the ancient Greeks. Modern science has not settled those questions. The questions are certainly not settled by just declaring that time is a coordinate.

SciAm reports:

As troubling as quantum mechanics (or at least certain versions of it) may be for the idea of free will, relativity—the other pillar of modern physics—isn’t off the hook. Many theorists think of relativity as describing a universe in which past, present and future are all equally real: a static cosmos that just sits there like a big block of spacetime (sometimes called the “block universe”). It’s not that time disappears in this picture—but it no longer “passes” or “flows.” (As Albert Einstein famously put it, the passage of time is a “stubbornly persistent illusion.”) Conceptually speaking, the strongly deterministic quantum universe and the block universe of relativity may not be so far apart. The quantum version can be thought of as “a kind of enriched block universe,” says Alastair Wilson, a philosopher of science at the University of Leeds in England. “Imagine taking a block universe and adding an extra dimension to it—the dimension of possibility.” ...

Even without relativity, you could use a time coordinate to make a block universe. You can use any coordinates you want. Choosing some coordinates cannot possibly say anything about free will.

Many-worlds theory takes this to the next step, if you put all those many worlds in a big block multiverse.

While physicists continue to debate the idea of strong determinism, Emily Adlam, a philosopher of physics at Chapman University, agrees with Chen that it appears to present more of a threat to free will than traditional determinism, particularly because of its ties to the Everettian multiverse. “In a standard deterministic picture, sure, everything that happens was determined from the past—but your mind was a key part of the causal process by which future events get realized,” Adlam says. “So in some meaningful sense, future events—even though they were predetermined—were mediated through processes that you identify with yourself.” But in the Everettian picture, she says, it’s harder to see where decision-making would fit in. “If you always make every possible decision, that does seem to severely undermine the sense in which you are exercising any meaningful kind of choice,” she says. “So in that sense, you do seem worse off than in the standard picture, where one outcome occurs and you play a role in bringing it about.”
It goes on to say that this is controversial, as there are compatibilists who can rationalize belief in free will no matter what soft of determinism there is.

There is no mention of anyone who believes in true free will, now called libertarian free will.

The whole point of the article is to say that many-worlds theory presents a new argument against free will. Since all choices happen in parallel worlds simultaneously, then all choice possibilities are real, and humans cannot make any free will choices. That are all illusions.

This is absurd.

I wonder what Plato and Aristotle would say if we could go back in time, and tell them about our progress. We could tell them about rockets, cars, lasers, electronics, and drugs, and they would be impressed.

And then we would tell them that our best and finest theory of matter, quantum mechanics, has been interpreted to say that there is no free will, because we can imagine parallel universes where alternative decisions are made. They would rightfully conclude that we have made no progress in philosophy at all, and even regressed to some very silly ideas.

Thursday, May 23, 2024

There is Nothing Non-entangled in QM

Supposedly entanglement is the most important thing in quantum mechanics (QM). It is said to be the key feature that distinguishes QM from classical mechanics.

But what is it?

New paper:

Everything is Entangled in Quantum Mechanics: Are the Orthodox Measures Physically Meaningful?

Christian de Ronde, Raimundo Fernandez Moujan, Cesar Massri

Even though quantum entanglement is today's most essential concept within the new technological era of quantum information processing, we do not only lack a consistent definition of this kernel notion, we are also far from understanding its physical meaning [35]. These failures have lead to many problems when attempting to provide a consistent measure or quantification of entanglement. I

According to a lot of modern scholars, entanglement is a resource that can be exploited to give secure communication and super-Turing computability.

The paper discuss various definitions in the literature and concludes:

We have shown how entanglement, as the unitary multiscreen effect of a single power, is an irreducible aspect of the operational content of the theory of quanta. The theory talks about powers of action each one them producing a multiscreen (non-local) effect that can be observed in the lab. Consequently, there is nothing non-entangled in QM. There is no meaningful distinction between something that is entangled and something that is not entangled within the theory of quanta. The attempt of quantifying or measuring the level of entanglement becomes meaningless.
I think that entanglement is not something real. It is an artifact of how QM works, but there is no way to objectively say whether a particle is entangled or not. So we should not talk about entanglement as if it is some mysterious resource.

Maybe I will be proved wrong by some quantum computer that uses entanglement to break RSA or some other calculation that cannot be done otherwise. Then I will have to admit that entanglement is real and useful. But nothing like that has ever been done.

Sean M. Carroll tries to explain entanglement in a recent podcast:

I 0:20 think you know entanglement arises 0:22 directly from that statement we made 0:23 long ago that when you have a Quantum 0:25 system you do not have separate wave 0:27 functions for each part of it you only 0:29 have one wave function for the whole 0:30 thing and the job of the wave function 0:33 is to make predictions for observational 0:35 outcomes so if that's all true then it 0:38 could be the case that if you predict 0:41 the outcome for one thing and another 0:43 thing particle a and particle B there 0:46 might be correlations or connections 0:48 between those measurement outcomes so I 0:50 don't know what I'm going to see when I 0:52 ask what is the spin of particle a and I 0:54 don't know what I'm going to see when I 0:56 ask what is the spin of particle B but I 0:58 know they're going to be opposite so 1:00 then that's entanglement and it tells me 1:02 were I to measure particle a I have no 1:04 idea what I'm going to observe but as 1:06 soon as I do I know what the outcome is 1:08 for particle B and this bugs people 1:11 because how does particle B know what 1:13 its outcome is supposed to be it could 1:15 be light years away
If this is the definition of entanglement, then there is nothing quantum mechanical about it. Classical physics shows the same phenomenon.

If split a classical system with angular momentum zero, separate the halves, and measure the angular momentum of one half, then the other half will have the opposite angular momentum. Just like how Carroll described QM.

When asked for more explanation, he says that he prefers the Everett many-worlds interpretation. However he admits that no one knows whether the effect of a measurement propagates at the speed of light or less in the universal wave function, or propagates instantaneously.

What? I thought that the whole point of Everett was to clarify what happens quantum mechanically when a measurement takes place. But if he cannot tell how the result propagates, then I do not see how it can tell me anything.

See also this podcast, where he starts by saying the Everestt theory is the most straightforwad interpretation of the Schroedinger equation, but it requires splittings into parallel worlds and we do not know what a world is. We also do not know if the wave function is real. Later, at 45:30 he says, "I mean the real answer there is I don't think about all those other worlds, that much again the worlds are a prediction of the theory they're not what the theory is fundamentally about."

Carroll goes on to explain the Bell tests:

also in the 1960s John Bell proved his 6:17 theorems he proved theorems about the 6:20 different predictions between a local 6:22 Theory and a non-local theory like 6:24 quantum mechanics and that made it an 6:27 experimentally accessible question so 6:29 people did the experiment and they just 6:31 won the Nobel Prize a couple years ago 6:33 so physicists are very interested now 6:35 because there's an experiment you can do 6:37 of course the experimental result was 6:38 exactly what schrodinger would have 6:40 predicted back in the 1920s it didn't 6:42 change our idea of quantum mechanics but 6:44 as long as you can do an experiment 6:45 they're happy having said that because 6:48 physicists have ignored the foundations 6:49 of quantum mechanics for so long even 6:52 the Nobel Prize press release botched it 6:55 they gave the wrong explanation for what 6:57 was going on because they didn't really 6:59 understand what they just give the Nobel 7:00 Prize
Again, this is startlingly foolish. He correctly says that the prize-winning experiments just confirmed what quantum mechanics would have predicted in the 1920s, and did not change our idea of quantum mechanics.

So how did the Nobel press release botch it? It certainly did not say that the experiment changed our view of QM. That would have been big news. See my earlier post for more details.

Carroll's real gripe is that he wants to fund more research in the foundations of QM, and the Nobel committee refused to acknowledge that the experiments left unsettled issued. In particular, he wants to push many-worlds theory, but it gets no Nobel endorsement. The Nobel committee correctly said that the experiments confirmed what everyone thought for many decades.

Monday, May 20, 2024

Einstein's Futile Search for Unified Field Theory

Sabine Hossenfelder posted her latest video:
Einstein’s Other Theory of Everything

Einstein completed his theory of general relativity in 1915 when he was 37 years old. What did he do for the remaining 40 years of his life? He continued developing his masterwork of course! Feeling that his theory was incomplete, Einstein pursued a unified field theory. Though he ultimately failed, the ideas he came up with were quite interesting. I have read a lot of old Einstein papers in the past weeks and here is my summary of what I believe he tried to do.

She insists on pronouncing his name INE-shtine. Maybe Germans pronounce it that way, but not Americans.

She summarizes Einstein's foolish and misguided unified field theories. If he did not already have a fancy reputation, this would be considered crackpot work.

She also mentions the more successful Kaluza–Klein theory:

In physics, Kaluza–Klein theory (KK theory) is a classical unified field theory of gravitation and electromagnetism built around the idea of a fifth dimension beyond the common 4D of space and time and considered an important precursor to string theory. In their setup, the vacuum has the usual 3 dimensions of space and one dimension of time but with another microscopic extra spatial dimension in the shape of a tiny circle. Gunnar Nordström had an earlier, similar idea.
This is also described as a failure. She says you need supersymmetry to make it work, but that has been rejected.

That theory is a minor variant of a 1918 H. Weyl proposal to unify gravity (general relativity) and electromagnetism. That was promptly attacked by Einstein, and mostly forgotten.

There the story ends. But not really. Einstein's ideas were, in fact, worthless, and led several generations of physicists astray. I wrote a whole book about it.

But Weyl's idea was essentially correct. In the modern Standard Model, that everyone accepts, there is an extra tiny circle at every spacetime point (event) to account for electromagnetism. In modern lingo, it is a circle bundle over a spacetime manifold. Gravity is a connection on the tangent bundle, and electromagnetism is a connection on the circle bundle. In both cases, the field is the curvature. It is the simplest and most natural relativistic theory.

Physicists studied Weyl and Kaluza-Klein for decades, without ever figuring out that they were just adding extra terms that ruined the theory. I guess they wanted to unify the gravity with the electromagnetism by hypothesizing some interactions, but that was just foolishness.

If Weyl were really smart, he would have conjectured using other Lie groups form the strong and weak interactions, alongside the circle for electromagnetism. Then we could have had the Standard Model, before quantization, about 50 years before we did.

One of the Lessons of the Standard Model is that all four forces (gravity, electromagnetism, weak, and strong) all have the same math structure (field strength is curvature of a bundle connection), but the force are essentially orthogonal. They do not have much to do with each other. There is some twisting between the weak and electromagnetism, but that's all. Many people thought that they would be unified like electricity and magnetism, where you cannot study one without the other.

Wednesday, May 15, 2024

Gravity is a Force

Physicists are sharply divided over whether gravity is a force. Oh, they refer to it as a force all the time, such as saying it is one of the four fundamental forces, but then say it is a fictitious force.

The excellent video channel Veritasium has explanation of Why Gravity is NOT a Force.

It is like the people who say that centrifugal force is not a force, but centripetal forces is.

Gravity has been considered a force since Newton in the 1600s, so the opposite view requires explanation.

Actually, it is not so clear that Newton believed that gravity was a force. He was very much against action-at-a-distance:

Newton famously struggled to find out the cause of gravity.[12] In a letter to Bentley, dated January 17 1692/3, he said:

You sometimes speak of Gravity as essential and inherent to Matter. Pray do not ascribe that Notion to me, for the Cause of Gravity is what I do not pretend to know, and therefore would take more Time to consider it. (Cohen 1978, p. 298)

In a subsequent letter to Bentley, dated February 25, 1692/3, he added:

It is inconceivable that inanimate Matter should, without the Mediation of something else, which is not material, operate upon, and affect other matter without mutual Contact…That Gravity should be innate, inherent and essential to Matter, so that one body may act upon another at a distance thro’ a Vacuum, without the Mediation of any thing else, by and through which their Action and Force may be conveyed from one to another, is to me so great an Absurdity that I believe no Man who has in philosophical Matters a competent Faculty of thinking can ever fall into it. Gravity must be caused by an Agent acting constantly according to certain laws; but whether this Agent be material or immaterial, I have left to the Consideration of my readers. (Cohen 1978, pp. 302-3)

Aristotle also denied that gravity was a force.
The Aristotelian explanation of gravity is that all bodies move toward their natural place.

There are two arguments that gravity is not a force. One says that you do not feel gravity in free fall. You feel it when you stand on the ground, but you are really feeling the force of the ground pushing you up.

The second is that general relativity teaches that gravity is just curvature of spacetime, not a force. This is a variation of Aristotle's argument.

A typical explanation:

“The one sentence statement of general relativity is that ‘gravity is the curvature of spacetime,’” explains Dr. Sean Carroll, assistant professor of physics at the University of Chicago. “Really, the differences come in understanding what that sentence means.”

Carroll says that origin of the theory of general relativity dates to 1905, when scientists, notably including Albert Einstein, realized that space and time are related characteristics of a four-dimensional existence. ...

However, within this new 4-D framework, says Carroll, Einstein could not understand gravity, and how it worked in spacetime. He decided that rather than being a force, like electromagnetism, gravity must be a property: a geometric curvature.

This stuff about Einstein believing that gravity is geometrical curvature is a modern invention. Yes, he used the equations for curvature, but did not subscribe to the geometric interpretation that is popular today.

General relativity differs very slightly from Newtonian gravity. It is silly to say one is a force and the other not. They are essentially the same.

My biggest quibble is with those who say electromagnetism is a force, but gravity is not. In modern physics, all of the four fundamental forces have geometrical interpretations, where the field strength is given by curvature. Test particles follow curvature, in all cases. Here is a recent paper explaining it. So if gravitational forces are fictitious because particles are just following curvature, then nothing else is a force either.

Those who deny that gravity is a force sometimes go one step farther, and deny causality. Eg, from the Stanford Encyclopedia:

Causation in Physics

What role, if any, do causal notions play in physics? On the one hand, it might appear intuitively obvious that physics aims to provide us with causal knowledge of the world and that causal claims are an integral part of physics. On the other hand, there is an influential philosophical tradition, dating back to Ernst Mach and to Bertrand Russell’s extremely influential article “On the Notion of Cause” (1912), denying the applicability or at least the usefulness of causal notions in physics. While this tradition is perhaps not as dominant today than it once was, there continues to be a lively and active philosophical debate on whether causal notions can play a legitimate role in physics and, if yes, what role that might be.

One part of this is that if you believe in determinism and the block universe, then the Big Bang caused everything, and nothing else had any influence.

I take the view that we have forces and causes. I am all in favor of the geometrical interpretation, but not to deny forces and causes.

While I think most physicists take a geometrical view, here is a new oddball paper:

A Puzzle About General Covariance and Gauge

Eleanor March, James Owen Weatherall

We consider two simple criteria for when a physical theory should be said to be "generally covariant", and we argue that these criteria are not met by Yang-Mills theory, even on geometric formulations of that theory. The reason, we show, is that the bundles encountered in Yang-Mills theory are not natural bundles; instead, they are gauge-natural.

Of course Yang-Mill (gauge) theories are generally convariant, as the theory is independent of any particular coordinates. If you change coordinates, then the equations of motion transform as you expect from vectors and tensors.

The paper makes the trivial point that if you change the coordinates, that does not necessarily tell you how to change the gauge. Yang-Mill theories are covariant over a change in coordinates and gauge.

These confusing arguments only obscure the fact that gravity, electromagnetism, strong, and weak forces all use the same geometrical constructions. Just the bundles are different. Gravity uses the tangent bundle on spacetime, while the other forces use U(1), SU(3), and SU(2) bundles. They are all covariant.

The Wikipedia article on general covariance says that Einstein popularized the term, but did not use it precisely. So I guess that is why some might think that it applies to general relativity, but not to other bundles.

Update: Here is a new paper explaining general covariance.

The free field then couples to the gauge field, producing an interaction term in the Lagrangian that is gauge-invariant. Neither the original electron field, nor the gauge field are gauge invariant, but the way they appear in the Lagrangian is through a gauge invariant term. One then proceeds to define gauge invariant things like the tensor field 𝐅:=d⁢𝐀 and claims that the physics of the theory is contained only in those objects.

Likewise, diffeomorphisms in GR are regarded as extra, unphysical degrees of freedom: the physics must be contained only in gauge-invariant quantities. This is in flagrant contrast with what experience tells us: in ‘real life’ things are constrained to fixed frames of reference, and one can measure ‘gauge-variant’ [8] quantities, such as the energy, proper time, the electric field, and so on.

Friday, May 10, 2024

Wilczek says Falling Cats have Free Will

Physicist Frank Wilczek is famous for helping explain the short range nature of the strong force, and now he wrote a strange paper on cats. No, not Schroedinger cats.
Free Will and Falling Cats

If we consider a cat to be an isolated mechanical system governed by T-invariant mechanics, then its ability to land on its feet after being released from rest is incomprehensible. It is more appropriate to treat the cat as a creature that can change its shape in order to accomplish a purpose. Within that framework we can construct a useful and informative of the observed motion. One can learn from this example.

He seems to be saying that it is impossible for a falling cat to land on its feet, unless it has free will.

He proves it is impossible, but then says cats have a loophole because "They can readily and selectively consume stored energy, notably by converting ATP into ADP, empowering mechanical motion accompanied by radiation of heat."

This is bizarre. The physics of falling cats is well-understood, and does not require free will or ATP or heat or anything like that. See A simple model for the falling cat problem. There is even a Wikipedia article on it.

The paradox is that the cat falls with zero angular momentum, a conserved quantity, and it is hard to see how it can get its feet down without some angular momentum. But as the above paper explains, the cat can twist its body without any net angular momentum.

Wilczek has some philosophical comments that went over my head, so maybe I am not fully appreciating his paper. After all, he has a Nobel Prize and I don't. What am I missing? He does cite a book on "Falling Felines and Fundamental Physics", so he must know that this is understood.

Wednesday, May 8, 2024

Carroll Eulogy for Dan Dennett

Physicist Sean M. Carroll released his latest AMA podcast. He starts with a eulogy.
Dan Dennett you know was not only a hugely important 1:02 philosopher for the 20 and 21st century uh and a mindscape guest but also a personal friend so that hit very hard I 1:09 was sitting at a table with Dan and a bunch of other philosophers just a few 1:15 weeks ago at Santa Fe
He particularly praised Dennett for giving philosophical defenses of Atheism and Darwinism, and saying the mind is just a machine, so consciousness and free will are just illusions. But he was very much against telling the hoi polloi that they have no free will, or they may decide that they have no moral responsibility for their actions.

In past generations, philosophers did not want to inform us that God is dead, or that we are descended from apes.

Next, Carroll praised counterfactual reasoning.

ml pickle says your recent guests have 21:43 pointed to counterfactual reasoning as a key element of human advancement either as mental time travel or considering the 21:49 consequences of different initial conditions or empathy for the plights of others Etc I've begun to notice how 21:55 often I do it and to suspect it's true that Ed ability for example and perhaps 22:00 our overall success as a species depend upon it however I can't tell if it is required or most efficient or if it just 22:07 happens to be what I personally do how important do you think counterfactual reasoning is to effective prediction as 22:13 individuals or to our past and future advancement as a species it's hard to answer I mean that 22:20 the answer is super important basically but when you ask you know how important is it I'm not quite sure what how to 22:26 quantify it right um but I do do think that this idea of counterfactual reasoning maybe the first time we talked 22:31 about it was with Malcolm mcgyver when he was talking about the the initial evolutionary development of the capacity 22:38 for counterfactual reasoning when fish climbed onto land and could suddenly see a lot further than they could before and 22:46 yeah you're right we've talked about um people who have been thinking more specifically about how humans use those 22:52 capacities um I you know it's hard to imagine something oh Carl friston we 22:58 actually also talked with about that issue cuz I was I remember joking with him that of my two cats Ariel and 23:04 calaban one seems to be capable of counterfactual reasoning and one does not calaban just seeks the local minimum 23:10 he just wants to be as happy as possible in the moment I don't think the idea of other moments ever occurs to him whereas 23:15 Ariel is the stereotypical cat who you know when you open a door that she demands to have open she's like I don't 23:21 know do I want to open that do I want to walk to that threshold I'm not quite sure she's always thinking about the 23:26 possible bad consequences Etc and our uh feral cat our outdoor cat Puck who has 23:32 uh hung around outside our yard for a while um he's super cautious right 23:38 because this is what is keeping him alive so he doesn't do anything until he like thinks about it 20 different ways 23:43 so somewhere that's that's close to when this capacity in some minor uh key was 23:49 first developed evolutionarily but anyway yeah absolutely possible AB absolutely crucial because I think that 23:57 I suspect and I'm just making stuff up I'm not an expert on this but I suspect that the parts of the brain that are 24:03 good at in general abstract symbolic reasoning are either the same as or 24:09 closely related to the parts of the brain that are that are good at counterfactual reasoning
I would agree with this, except that there is no way to reconcile this with his views on many-worlds theory. In many-worlds, all counterfactual scenarios happen, so there is no such thing as a counterfactual.

If he really believed in many-worlds, there would be no free will either. Every decision is just a splitting of the worlds, with both branches equally real.

He also expresses support for the anti-Israel protests currently going on at college campuses.

The podcast goes on for three more hours. Let me know if I missed anything good.

Monday, May 6, 2024

Unscientific American

James B. Meigs writes:
Science journalism surrenders to progressive ideology.

Michael Shermer got his first clue that things were changing at Scientific American in late 2018. The author had been writing his “Skeptic” column for the magazine since 2001. ...

Shermer dug his grave deeper by quoting Manhattan Institute fellow Heather Mac Donald and The Coddling of the American Mind authors Greg Lukianoff and Jonathan Haidt, who argue that the rise of identity-group politics undermines the goal of equal rights for all. Shermer wrote that intersectional theory, which lumps individuals into aggregate identity groups based on race, sex, and other immutable characteristics, “is a perverse inversion” of Martin Luther King’s dream of a color-blind society. For Shermer’s editors, apparently, this was the last straw. The column was killed and Shermer’s contract terminated. Apparently, SciAm no longer had the ideological bandwidth to publish such a heterodox thinker.

The article gives many examples.

I have criticized these SciAm trends for years.

Maybe the title should be Unscientific Unamerican, since the magazine is now owned by a British company.

Saturday, May 4, 2024

Many-worlds does not Solve the Measurement Problem

Brian Greene's third interview is with Carlos Rovelli:
I'll now give you a brief 0:21 summary of where we have gotten so far all right in our first conversation with 0:26 philosopher Elise Crow we discussed the basics of quantum mechanics namely that 0:33 the theory has at its core the idea that the best you can ever do in our reality 0:39 is make probabilistic predictions ...

we also explored how through quantum 1:36 entanglement reality has what we call a nonlocal quality that is what you do 1:42 here can have an instantaneous Quantum impact on something way over there and 1:48 such non-locality we found can thread not just through space but also through time

all right in 1:56 our second conversation with physicist and author Sean Carol we explored a 2:01 number of proposed resolutions to the quantum measurement problem most notably 2:07 spontaneous collapse theories as well as the many worlds interpretation of 2:13 quantum mechanics in which every possible Quantum outcome actually 2:18 happens but each takes place in its own Quantum Universe

No. Nothing can have an instantaneous nonlocal impact, and many-worlds does not solve the measurement problem.

I am surprised Greene would say this, because the advocates of many-worlds theory do not even claim to solve the measurement problem.

They argue that there is a wave function of the universe, and that the function will explain everything we see. Any mystery might be answered by understanding this function better. But it does not tell us why we see one outcome.

Or so I thought. I asked ChatGPT:

The many-worlds interpretation (MWI) is a fascinating and controversial view in quantum mechanics. Let’s delve into it and explore how it relates to the quantum measurement problem.

The Quantum Measurement Problem

The measurement problem arises from the mysterious behavior of quantum systems during measurement or observation. Here’s a brief overview:

1. Wavefunction Collapse: Before a measurement, a quantum system exists in a superposition of all possible states described by its wave function. However, upon measurement, the wave function appears to “collapse” to a specific state, leading to the observed outcome. This collapse is puzzling because it seems to violate the unitary evolution of quantum mechanics.

2. Where Do Other Possibilities Go?: If all possible outcomes of a quantum measurement have real existence, why do we observe only one outcome? What happens to the other possibilities?

Many-Worlds Interpretation (MWI)

The MWI, proposed by physicist Hugh Everett, offers an intriguing solution to the measurement problem. Here are the key ideas:

1. Parallel Universes: According to the MWI, the universe doesn’t collapse into a single state during measurement. Instead, it branches into multiple parallel universes, each corresponding to a different measurement outcome. In other words, every possible outcome occurs in a separate universe.

2. Wave Function Never Collapses: In the MWI, there is no collapse of the wave function. Instead, the entire universe (including the observer) evolves as a superposition of all possible states. Each branch represents a different version of reality, with no need for collapse.

3. Replicas of You and Me: In these parallel universes, there exist replicas of you and me, leading other lives. Each replica experiences a different outcome of the measurement. These universes coexist but remain mutually isolated.

Controversy and Philosophical Implications

The MWI challenges our understanding of knowledge and reality:

Controversy: Debates about quantum interpretations can be passionate, and the MWI is no exception. Some physicists find it elegant, while others reject it due to its radical departure from classical intuition.

Epistemological Question: The MWI raises fundamental questions about what constitutes knowledge. It challenges us to consider what kind of theory we accept as a claim to understand the world.

In summary, the MWI provides an alternative perspective that avoids wavefunction collapse, but it remains a topic of ongoing debate. Whether it fully solves the measurement problem is still a matter of interpretation and personal preference12. Feel free to explore further or ask more questions! 😊

I cites this Quanta article:
Why the Many-Worlds Interpretation Has Many Problems ...

it seemed that the central problem for quantum mechanics was the mysterious rupture created by observation or measurement, which was packaged up into the rubric of “collapse of the wave function.” ...

But Bohr and colleagues didn’t bring wave function collapse into the picture just to make things difficult. They did it because that’s what seems to happen. When we make a measurement, we really do get just one result out of the many that quantum mechanics offers. Wave function collapse seemed to be demanded in order to connect quantum theory to reality.

So what Everett was saying was that it’s our concept of reality that’s at fault. We only think that there’s a single outcome of a measurement. But in fact all of them occur. We only see one of those realities, but the others have a separate physical existence too.

Okay, I guess the Everett do claim that they have solved somethiung here. As you can see, they have not.

Thursday, May 2, 2024

New Greene Videos spread Quandum Misinformation

Physicist Brian Greene, known mainly for overhyping string theory, has new interviews of Elise Crull and Sean Carroll on quantum entanglement and related topics.

You should know to be suspicious when they say the Nobel Prize committee got something wrong. Carroll complains that they gave a prize for disproving hidden variables, even though Einstein, Bohm, and Bell believed in hidden variables.

Yes, the prize was for doing experiments to prove them wrong.

Greene lets Carroll plug his favorite, many-worlds theory. They claim it is somehow simpler to assume zillions of unobservale worlds.

They do put their finger on the heart of the problem -- the theory requires rejecting probabilities.

Usually, when a theory assigns a probability to an event, it is an estimate of the likelihood. of the event occurring versus not occurring. Carroll has to reject that whole way of thinking. He has to say all events occur, and deny that probabilities mean anything.

He admits that many-worlds does not match our real-world experience, but says we need more research on the foundations of Physics to figure it out.

He complains that universities do not want people like Bohm and Bell who are concerned with this stuff. Actually he admits that they did not want Bohm because he was a Commie, and got his degree under the Commie J. R. Oppenheimer.

They all give misleading descriptions of nonlocality. There is no quantum nonlocality in the sense that doing something in one place has an immediate effect on a distant place.

There has been no Nobel Prize for quantum nonlocality. They also complain that the textbooks do not explain quantum mechanics adequately. This should make you suspicious. How is it that these guys have some profound quantum insights that are not recognized by the Nobel committee or the textbooks?

I am afraid that people watch these videos and think that they are learning something. No, they are getting some fringe ideas that mainstream physicists say is wrong.

Update: Carroll says:

just say we have a wave function and not only the electron has a wave function but you and I are part of the wave 11:14 function of the universe and we just ask what would be predicted by the [Schroedinger] equation if if we went back to the has a wave function but you and I are part of the wave 11:21 classical Paradigm where we just have stuff and an equation yeah what would happen and the answer is that that part 11:28 of the wave function let's say that has the electrons spin up and spin down it doesn't disappear when you do a 11:34` measurement a measurement is clearly defined in this picture as a physical interaction between the Observer and the 11:40 system and the decoherence part is also important and what happens is you end up in a 11:46 superposition of the electron was spin up and I saw it spin up plus the 11:51 electron was spin down and I saw it spin down and ever's entire contribution was to say and that's okay and ... yeah it's the leanest and meanest version of quantum mechanics it's just there's a wave function and an equation everything else pops
This is a little hard to follow, but he says classical mechanics uses equations to make predictions, and many-worlds is just doing the same thing to use the Schroedinger equation to make predictions.

But the equations of classical mechanics can also be used to predict probabilities. When you do, and make an observation that rules out some possibilites, then the appropriate state functions are updated accordingly. No one says that the equations create parallel worlds. So classical and quantum mechanics are essentially the same in this respect.

Carroll would say that hte difference is that the probabilities are real and fundamental in quantum mechanics, but not classical mechanics. But that is just his personal philosophical opinion.

Monday, April 29, 2024

Baggot has a New Book on Quantum History

Jim Baggott wrote an essay plugging his latest book:
‘Shut up and calculate’: how Einstein lost the battle to explain quantum reality

By suppressing questions they considered too ‘philosophical’, post-war physicists created an unquestioning orthodoxy that influences science to this day.

I agree that Einstein lost the battle, and that mainstream physicists came to the conclusion that pursuing philosophical questions is an unscientific waste of time.
Quantum mechanics is an extraordinarily successful scientific theory, on which much of our technology-obsessed lifestyles depend. It is also bewildering. Although the theory works, it leaves physicists chasing probabilities instead of certainties and breaks the link between cause and effect. It gives us particles that are waves and waves that are particles, cats that seem to be both alive and dead, and lots of spooky quantum weirdness around hard-to-explain phenomena, such as quantum entanglement.
Yes, QM is successful and works. But it is nonsense to say it is deficient because it "leaves physicists chasing probabilities instead of certainties and breaks the link between cause and effect." All scientific theories do that, to the extent QM does.
How, then, is the correlation established? Do the particles somehow remain in contact, sending messages to each other or exerting influences on each other over vast distances at speeds faster than light, in conflict with Einstein’s special theory of relativity?

The alternative possibility, equally discomforting to contemplate, is that the entangled particles do not actually exist independently of each other. They are ‘non-local’, implying that their properties are not fixed until a measurement is made on one of them.

Both these alternatives were unacceptable to Einstein, leading him to conclude that quantum mechanics cannot be complete.

Those alternatives are also unacceptable to Bohr and most followers of the Copenhagen interpretation. The particles do exist locally, and are not in contact with distant particles.

The paradox occurs when Einstein tries to complete QM by adding some unobservable ideas. If you stick to Bohr's positivism, all is fine.

It seemed that dissidents faced serious repercussions. When US physicist John Clauser — a pioneer of experimental tests of quantum mechanics in the early 1970s — struggled to find an academic position, he was clear in his own mind about the reasons. He thought he had fallen foul of the ‘religion’ fostered by Bohr and the Copenhagen church:
Clauser was trying to disprove QM. Had he succeeded, he would have been a big hero. As it was, his work was not interesting to those who thought that QM was well-tested, and his research would not find anything new.

Yes, Clauser did eventually get a Nobel Prize, but not for discovering any new physics. Only for confirming what everyone knew. In particular, the Nobel committee did not criticize the Copenhagen interpration, or endorse Einsteinian completeness or nonlocality.

The Americanization of post-war physics meant that no value was placed on ‘philosophical’ debates that did not yield practical results. The task of ‘getting to the numbers’ meant that there was no time or inclination for the kind of pointless discussion in which Bohr and Einstein had indulged.
Yes, that was the Golden Age of American science. Doing good science, instead of the meaningless philosophical ideas that have diverted physicists today, such as string theory, many-worlds, etc.
These developments conspired to produce a subtly different kind of orthodoxy. In The Structure of Scientific Revolutions (1962), US philosopher Thomas Kuhn describes ‘normal’ science as the everyday puzzle-solving activities of scientists in the context of a prevailing ‘paradigm’. This can be interpreted as the foundational framework on which scientific understanding is based. Kuhn argued that researchers pursuing normal science tend to accept foundational theories without question and seek to solve problems within the bounds of these concepts. Only when intractable problems accumulate and the situation becomes intolerable might the paradigm ‘shift’, in a process that Kuhn likened to a political revolution.
Kuhn then wrote a book on a history of the discovery of QM, and he failed to find a paradigm shift or anything matching his wacky theory of scientific revolutions.
A persistent myth was created that suggests Bohr won the argument by browbeating the stubborn and increasingly isolated Einstein into submission. ...

My latest book Quantum Drama, co-written with science historian John Heilbron, explores the origins of this myth and its role in motivating the singular personalities that would go on to challenge it. Their persistence in the face of widespread indifference paid off, because they helped to lay the foundations for a quantum-computing industry expected to be worth tens of billions by 2040.

I will skip this book. He is peddling nonsense that got resolved decades ago. Questioning the Copenhagen interpretation has not led to any advances in quantum computing or anything else. I do not believe the quantum computing industry will be worth anything in 2040. It has no proven value so far.

All of the quantum computing researchers use the Copenhagen interpretation to design and carry out their experiments. There are a few who think that the results might be better understandable with many-theory, but many-worlds and non-local theories have had zero influence on the research. There is no chance that quantum computers will prove Einstein right, or Bohr wrong, or anything like that.

Monday, April 22, 2024

Critical Step in Quantum Networking

NewsL
Researchers have produced, stored, and retrieved quantum information for the first time, a critical step in quantum networking.

The ability to share quantum information is crucial for developing quantum networks for distributed computing and secure communication. Quantum computing will be useful for solving some important types of problems, such as optimizing financial risk, decrypting data, designing molecules, and studying the properties of materials.

“Interfacing two key devices together is a crucial step forward in allowing quantum networking, and we are really excited to be the first team to have been able to demonstrate this.” — Dr. Sarah Thomas

However, this development is being held up because quantum information can be lost when transmitted over long distances. One way to overcome this barrier is to divide the network into smaller segments and link them all up with a shared quantum state.

To do this requires a means to store the quantum information and retrieve it again: that is, a quantum memory device. This must ‘talk’ to another device that allows the creation of quantum information in the first place.

For the first time, researchers have created such a system that interfaces these two key components, and uses regular optical fibres to transmit the quantum data.

There is no commercial value in this or quantum networking. No one is going to use this to optimize financial risk, design molecules, or increase the secutiry of anything.

Tuesday, April 16, 2024

Higgs has died

Physicist Lawrence M. Krauss writs:
Higgs wrote up his idea in a two-page scientific paper entitled “Broken Symmetries and the Masses of Gauge Bosons.” It was initially rejected by the major European physics journals, as having no obvious relevance to physics. But then he added a paragraph mentioning a possible observable consequence of his idea and submitted his paper to the American physics journal, Physical Review Letters, where it was published on 19 October 1964. Similar ideas were explored by the physicists Robert Brout and François Englert, and independently by Gerald Guralnik, C.R. Hagen, and Tom Kibble, and these two groups also published their work in the same journal. But, perhaps as a result of that extra paragraph that predicted a physical consequence of his theory, it was Higgs’s name that became associated with the hypothesis, which ended up providing the cornerstone of the successful effort to unify two of the four known forces in nature: the weak and electromagnetic interactions. 
CERN discovered the Higgs particle in 2012, and he got the Nobel Prize in 2013, and it ruined his life.

Okay, but I do not see why Higgs had to predict the particle, and CERN find it, for him to get the prize.

The Higgs mechanism is essential to the Standard Model, and to all the cutting edge high-energy physics since about 1970.

The other ctitical piece was tHooft's renomalization of gauge theories in about 1970. That made gauge theories the only game in town, with SU(2) for the weak and SU(3) for the strong force. 'tHooft got the Nobel Prize in 1999. He should have also gotten the prize in the 1970s, when experiments confirmed the Standard Model.

Thursday, April 4, 2024

Thank Gravitational Waves for Life

Phys.org reports:
Could it be that human existence depends on gravitational waves? Some key elements in our biological makeup may come from astrophysical events that occur because gravitational waves exist, a research team headed by John R. Ellis of Kings College London suggests.

In particular, iodine and bromine are found on Earth thanks to a particular nuclear process that happens when neutron stars collide. In turn, orbiting neutron star pairs inspiral and collide due to their emissions of energy in the form of gravitational waves. There may thus be a direct path from the existence of gravitational waves to the existence of mammals.

Humans are mostly made up of hydrogen, carbon and oxygen, with many additional trace elements. (There are 20 elements essential to human life.) Those with an atomic number less than 35 are produced in supernovae, implosions of stars that have exhausted their nuclear fuel and collapsed inward. The collapse results in an explosion that spews their atoms all over the universe.

But two elements are provided by other means—iodine, needed in key hormones produced by the thyroid, and bromine, used to create collagen scaffolds in tissue development and architecture. ...

Ellis and his colleagues calculate that the r-process has provided 96% of the abundance of 127I on Earth, an isotope essential for human life, and most of the abundance of bromine and gadolinium in the Earth's crust, plus all of the Earth's thorium and uranium and a fraction of the molybdenum and cadmium.

Seems farfetched, but interesting anyway. Here is the paper.

Update: Dr. Bee comments.

Monday, April 1, 2024

Sapolsky and Sam Harris on Free Will

Imagine that two schizophrenic have a discussion about hearing voices in their heads. They both agree that they hear voices, but then puzzle about how hard it is to convince others that the voices are real.

I used to thinjk that the anti-free-will advocates could not possibly believe what they are saying. Ordinary life requires making choices. Why do they get out of bed in the morning?

That is what this podcast is like:

We Really Don’t Have Free Will?: A Conversation with Robert M. Sapolsky (Episode #360)

Sam Harris speaks with Robert Sapolsky about the widespread belief in free will. They discuss the limits of intuition, the views of Dan Dennett, complexity and emergence, downward causation, abstraction, epigenetics, predictability, fatalism, Benjamin Libet, the primacy of luck, historical change in attitudes about free will, implications for ethics and criminal justice, the psychological satisfaction of punishing bad people, understanding evil, punishment and reward as tools, meritocracy, the consequences of physical beauty, the logic of reasoning, and other topics.

Robert M. Sapolsky is the author of several works of nonfiction, including A Primate’s Memoir, The Trouble with Testosterone, Why Zebras Don’t Get Ulcers, and most recently, Determined: A Science of Life without Free Will. His book titled Behave was a New York Times bestseller and named a best book of the year by The Washington Post and The Wall Street Journal. He is the John A. and Cynthia Fry Gunn Professor of biology, neurology, and neurosurgery at Stanford University and the recipient of a MacArthur Foundation “Genius Grant.” He and his wife live in San Francisco.

Okay, I am satisfied that some schizophrrenics hear voices in their heads, and Sapolsky and Harris have some other disorder controlling their brains. They adamantly argue that they have no choices in what they do.

Believe in free will or not as you please, but there is no law of Physics that requires the future to be determined by the past.

Thursday, March 28, 2024

“Don’t be a monkey!”

Lawrence M. Krauss writes:
I vividly remember the first time he showed me his famous video of capuchin monkeys—later to feature in a TED talk that has 23 million views and counting — in which two capuchin monkeys, kept in adjoining cages, are fed treats for exhibiting a certain behaviour. The monkeys were perfectly happy performing their task for cucumbers until, one day, one of the monkeys was rewarded with a grape instead. When the monkey’s companion was given a cucumber for the same task, he immediately proceeded to throw a temper tantrum worthy of a three-year old child — even though, five minutes earlier, he had been content with that reward. 

I immediately recognized the behaviour in myself! I showed the video to my wife, and ever since then, whenever I start to feel envious of someone for receiving any sort of reward that appears to be greater than that which I had previously been perfectly happy to receive during a similar experience, I tell myself, or my wife tells me: “Don’t be a monkey!”

He vividly recalls this, because he watched a cherry-picked video. You can read more in the Wikipedia article on Inequity aversion in animals.

The experiment has been repeated many times, with mixed results. Female (but not male) capuchin monkeys showed the effect, and so did some other species. Many experiments failed to find the effect.

I think the most interesting part of this is watching humans, like Krauss, watch this video and interpretation, and somehow think that they know what is going on inside the monkey's mind. I think they are projecting their own views onto the monkeys.

It is not clear that the monkey is feeling envy, or disapproval of the inequitable reward. If the monkeys were really rejecting inequity, then maybe the monkey getting the grape would give it to the other monkey. No, that does not happen.

It is hard to see how this says anything about cooperation, as these monkeys are lousy at cooperating on anything.

As for envy, it is not clear that the monkey cares at all what the other monkey is getting. Maybe the monkey notices that she could be getting a grape, and then rejects the lesser reward in order to get the grape. Indeed, this experiment has been done with just one monkey, and it just shows that the monkey wiil show that it wants the better reward.

I just tried showing the video to a ten-year-old boy, and asked him what he saw. He said, "i see a monkey who wanted a grape." When I explained that the grownup scientist interpreted this as a monkey protesting pay unfairness, he looked puzzled, and did not see why anyone would think that.

The TED Talk has a slide saying the Pillars of Morality are Reciprocity/Fairness and Empathy/Compassion. This is a very left-wing view that I call Kindergarten Morality. Kindergarten teachers commonly tell kids that they all have to share the toys equally, and show compassion to all. Older kids usually understand that such equality is impractical, and other moral concepts are more important. For more on how leftists have crippled moral outlooks, see Jonathan Haidt's Moral foundations theory.

Monday, March 25, 2024

Stealing our cutting edge String Theory

Eric Weinstein tweeted:
Q: How do you know that String Theory isn’t working as physics despite expert assurances to the contrary?

A: No one at all is in any way worried about the Iranians, Russians or Chinese getting their hands on our cutting edge String Theory.

Ha ha. Do they worry about enemies stealing our fusion reactor or quantum computer technology? Maybe a little bit.

Our semiconductor, rocket, and AI technology? A lot.

Weinstein has his own pet theories to replace the Standard Model of high-energy physics, but it has gone nowhere.

Update: Here is a video clip with more from him and Lee Smolin. Smolin also has his pet theories that have gone nowhere. Their complaint is not just that string theory does not work, but that it gets more attention than other thoeries that do not work.

For someone negative on the whole high-energy research program, see Unziger.

Monday, March 18, 2024

Deutsch defends Many-Worlds Theory

New podcast: The Multiverse is REAL - David Deutsch.

He says the double-slit experiment conclusively proves the many-worlds theory. He accepts the parallel worlds for the same reason he accepts the existence of dinosaurs (millions of years ago). It is the only way to explain the evidence.

He admits that the photons are not really particles, and that any waves show a similar diffraction pattern. But he says that for the photon to behave as a wave, it must exist in multiple copies.

He also admits that all this has been known for decades, and yet most physicists do not accept this argument for many-worlds.

I do not see any merit to this argument. The double-slit experiment only proves that light, and other beams like electron beams, have wave properties. That's all. It is not even evidence for quantum mechanics, as this wave explanation was accepted before quantum mechanics was invented.

When asked about alternative theories, he says the von Neumann had this crazy idea that if you observe an electron in one place, then the possibility of it being somewhere else ceases to exist.

I do not see the problem with that. I do not even think the issue has anything to do with quantum mechanics. Anytime you estimate the probability of an event, and then observe it, that means that the other possibilities did not happen. That is how probabilities work.

He pushes quantum computing, but admits that he has not followed the latest technology.

I see the argument for many-worlds as nothing more than a rejection of probability theory. You could take any scientific theory that predicts probabilities, deny that the probabilities make any sense, and conclude that there are parallel worlds of unobserved possibilities.

That is all many-worlds theory is. I don't think that it even has anything to with quantum mechanics. It is only expressed in terms of quantum mechanics, because textbook QM emphasizes the probabilities. But other theories use probabilities the same way, and could have many-worlds interpretations.

Many-worlds thsoey is just the same as taking a science textbook, announcing some philosophical disagreement with probability theory, and redacting all the sections mentioning probability. It adds nothing. It just removes the theory's predictive power.

It is hard to see how any intelligent man takes many-worlds seriously. It offers nothing. Maybe they just don't understand probability theory, as I do not see anywhere that they recognize that they are just rejecting probability.

PBS TV has a news item:

How quantum computing could help us understand more about the universe

Scientists, researchers and some big companies are eager to jumpstart the next generation of computing, one that will be far more sophisticated and dependent on understanding the subatomic nature of the universe. But as science correspondent Miles O’Brien reports, it’s a huge challenge to take this new quantum leap forward.

A lot of hype. They admit that a fault tolerant quantum computer might be decade away. No one admits that it might be impossible.

Monday, March 11, 2024

Physics v. Magic

From xkcd comics.

His point here is that Physics is inherently causal. Things happen because there is some causal sequence of interactions from event A to event B, when A causes B.

For example, the Sun's gravitational pull on the Earth was once thought to be action-at-a-distance, but is not thought of as the Sun perturbing spacetime and a wave traveling to Earth. Or gravitons traveling to Earth.

However Physics often reasons from results, without following a causal chain. Examples are thermodynamics, conservation laws, and Lagrangians.

There are also examples in quantum mechanics. A particle might tunnel through a wall, without any understanding of how it gets through the wall.

In spite os these example, I still believe the universe is inherently local, in cause and effect. Sometimes our reasoning can skip some steps, but only as a mathematical convenience. There is no action-at-a-distance, and no magic.

Monday, March 4, 2024

Poincare was Five Years ahead of Einstein

It is funny to see historians try to credit Einstein. Here is a 2013 essay I had not seen before:
On some points, such as the principle of relativity or the physical interpretation of the Lorentz transformations, Poincaré’s contributions preceded by at least 5 years those of Einstein’s published in 1905. On the other hand, many of their contributions were practically simultaneous. In 1905 Poincaré published an abridged version of his “Sur la dynamique de l’électron” [3] (which preceded the work of Einstein); the expanded version of the article appeared in 1906 [4].

What are the conceptual differences? According to Darrigol,

Einstein completely eliminated the ether, required that the expression of the laws of physics should be the same in any inertial frame, and introduced a “new kinematics” in which the space and time measured in different inertial systems were all on exactly the same footing. In contrast, Poincaré maintained the ether as a privileged frame of reference in which “true” space and time were defined, while he regarded the space and time measured in other frames as only “apparent.” …Einstein derived the expression of the Lorentz transformation from his two postulates (the relativity principle and the constancy of the velocity of light in a given inertial system), whereas Poincaré obtained these transformations as those that leave the Maxwell–Lorentz equations invariant [1].
These are conceptual differences that have no actual experimental consequences as far as electromagnetism and optics are concerned. As Lorentz commented, the difference is purely epistemological: it concerns the number of conventional and arbitrary elements that one wishes to introduce in the definitions of the basic physical concepts.

Are we then dealing with a case of simultaneous discovery?

No, it was not simultaneous. Poincare was five years ahead of Einstein. Poincare was years ahead of Einstein with the relativity principle, rejection of the aether, local time, synchronizing clocks, interpreting Michelson-Morley, Lorentz group, mass-energy equivalence, four-dimensional spacetime, and relativistic theories of gravity. Einstein's only claim to originality is to certain epistemological differences of no physical significance.

Credit Einstein with those obscure conceptual differences if you want, but there is no mathematical or physical value to any of them. Mostly they consist of mathematical misunderstandings by Einstein and other physicists. For example, there is nothing erroneous about choosing a privileged frame on a symmetric space. It does not break the symmetry. Those who criticize Poincare for occasionally choosing a privileged frame are just mathematically ignorant.

The essay concludes:

As Darrigol suggests, it seems wiser to concede that Lorentz, Poincaré and Einstein all contributed to the emergence of the theory of relativity, that Poincaré and Einstein offered two different versions of the theory, and that Einstein gave form to what today is considered the best one.
No, Einstein's is not considered best today. Nearly everyone prefers the spacetime formulation that Poincare advanced in 1905 and Minkowski perfected in 1907. Einstein was still rejecting it in 1911, and did not even speak positively about it until after that, and never really accepted the geometrical significance.

A lot of historians concede that Lorentz and Poincare had all the mathematics of special relativity, and all the physical consequences, but insist that Einstein had a more modern viewpoint or superior understanding, leading to how we understand the theory today. But that is false. The Poincare-Minkowski geometrical interpretation has been preferred by nearly everyone but Einstein, since 1908.

Saturday, February 24, 2024

Thursday, February 22, 2024

Chinese Deflate Quantum Hype Again

Sabine Hossenfelder is now doing short daily physics news videos, and her latest is on Bad News for Quantum Computing: Another Advantage Gone.

In short, quantum computing researchers have been claiming quantum supremacy for years. Some call it quantum advantage. However, there has never been any convincing demonstration that quantum computers have any speedup at all over conventional computers.

The latest is that IBM claimed last year to do a quantum calculation on a "noisy" quantum computer. Some thought that they had outdone Google. But a Chinese group outdid them by doing the calculation faster and better on a classical computer.

The quantum enthusiasts will argue, as usual, that this does not disprove quantum computing, and maybe a more clever experiment would show an advantage. I am waiting.

Monday, February 12, 2024

The physicists philosophy of physics

Princeton astrophysicist PJE Peebles writes:
The starting idea of the natural sciences is that the world operates by rules that can be discovered by observations on scales large or small, depending on what interests you. In fundamental physics, the subject of this essay, the idea is narrowed to four starting assumptions.

A: The world operates by rules and the logic of their application that can be discovered, in successive approximations.

B: A useful approximation to the rules and logic, a theory, yields reliably computed quantitative predictions that agree with reliable and repeatable mea- surements, within the uncertainties of the predictions and measurements.

C: Fundamental physical science is growing more complete by advances in the quantity, variety, and precision of empirical fits to predictions, and by occa- sional unifications that demote well-tested fundamental physical theories to useful approximations to still better theories.

D: Research in fundamental physical science is advancing toward a unique mind-independent reality.

These sound reasonable, but they leave no room for many-worlds theory, string theory, simulation hypothesis, superdeterminism, or many of the ideas that are now fashionables.

The essay gives way too much attention to philosopher Thomas Kuhn.

It quotes Einstein:

The supreme task of the physicist is to arrive at those universal elemen- tary laws from which the cosmos can be built up by pure deduction.
This sounds a little like Weinberg's mythical Final Theory, also discussed.

No, trying to build the cosmos from pure deduction is foolishness.

Thursday, February 8, 2024

Dissecting Einstein's Brain

The RadioLab podcast just rebroadcast this:
Albert Einstein asked that when he died, his body be cremated and his ashes be scattered in a secret location. He didn’t want his grave, or his body, becoming a shrine to his genius. When he passed away in the early morning hours of April, 18, 1955, his family knew his wishes. There was only one problem: the pathologist who did the autopsy had different plans.

In the third episode of “G”, Radiolab’s miniseries on intelligence, we go on one of the strangest scavenger hunts for genius the world has ever seen. We follow Einstein’s stolen brain from that Princeton autopsy table, to a cider box in Wichita, Kansas, to labs all across the country. And eventually, beyond the brain itself entirely. All the while wondering, where exactly is the genius of a man who changed the way we view the world?

Later in the show, it discussed theories for the origin of Einstein's most brillian idea -- special relativity. Besides his extra-smart brain, it mentioned his physicist wife and a philosopher. It even had professor Galison explaining how train schedules causes people to rethink time.

Okay, but there was no mention of Lorentz and Poincare, or the fact that they had published the entire theory ahead of Einstein.

Galison is unusual because he does not recite crazy stories about Einstein's originality, like other Einstein scholars. He read Lorentz and Poincare and obviously understands that they did it all first, but he refuses to comment on the priority dispute.

Monday, February 5, 2024

What's the difference, said Heisenberg

From a math site:
In the 1960s Friedrichs met Heisenberg and used the occasion to express to him the deep gratitude of mathematicians for having created quantum mechanics, which gave birth to the beautiful theory of operators on Hilbert space. Heisenberg allowed that this was so; Friedrichs then added that the mathematicians have, in some measure, returned the favor. Heisenberg looked noncommittal, so Friedrichs pointed out that it was a mathematician, von Neumann, who clarified the difference between a self-adjoint operator and one that is merely symmetric. "What's the difference," said Heisenberg.

- story from Peter Lax, Functional Analysis (slightly edited for length)

There is the difference between a physicist, and a mathematical physicist.

John von Neumann wrote a 1932 book on quantum mechanics, and turned it into a real theory.

To a physicist, an observable is a symmetric operator, because those are the ones that give real values, and only real values are observed. To von Neumann, an observable is a self-adjoint operator on a Hilbert space, where some additional technical requirements are needed in order to prove the spectral theorem.

I am not trying to say that Heisenberg was stupid. But it is striking that a world-famous physicist could get a Nobel Prize for using operators as observables, and still be oblivious to the formal mathematical definition found in textbooks. We cannot expect physicists to understand mathematical subtleties.

Thursday, February 1, 2024

The World is not Discrete

Some people like to say that Quantum Mechanics makes the world discrete. That is not true. But I always assumed that QM models could be approximated by lattice models.

Apparently this is not true. We know that the weak force is chiral, ie, it violates mirror reflection symmetry. Neutrinos are left-handed in the Standard Model.

From the Scott Aaronson blog:

“There is currently no fully satisfactory way of evading the Nielsen-Ninomiya theorem. This means that there is no way to put the Standard Model on a lattice. On a practical level, this is not a particularly pressing problem. It is the weak sector of the Standard Model which is chiral, and here perturbative methods work perfectly well. In contrast, the strong coupling sector of QCD is a vector-like theory and this is where most effort on the lattice has gone. However, on a philosophical level, the lack of lattice regularisation is rather disturbing. People will bang on endlessly about whether or not we live “the matrix’”, seemingly unaware that there are serious obstacles to writing down a discrete version of the known laws of physics, obstacles which, to date, no one has overcome.”
There is a whole industry of physicists doing lattice approximations to the SM, but the SM is chiral and the approximations are not, so there is no hope that the approximations converge to the SM.

Aaronson is commenting on the silly idea that we live in a computer simulation. If we did, it would raise another silly idea that we could overwork the simulator by doing certain experiments.

Monday, January 29, 2024

Quantum Computer Revolution may be Further off

IEEE Spectrum reports:
The quantum computer revolution may be further off and more limited than many have been led to believe. That’s the message coming from a small but vocal set of prominent skeptics in and around the emerging quantum computing industry.

The problem isn’t just one of timescales. In May, Matthias Troyer, a technical fellow at Microsoft who leads the company’s quantum computing efforts, co-authored a paper in Communications of the ACM suggesting that the number of applications where quantum computers could provide a meaningful advantage was more limited than some might have you believe.

“We found out over the last 10 years that many things that people have proposed don’t work,” he says. “And then we found some very simple reasons for that.” ...

Even in the areas where quantum computers look most promising, the applications could be narrower than initially hoped. In recent years, papers from researchers at scientific software company Schrödinger and a multi-institutional team have suggested that only a limited number of problems in quantum chemistry are likely to benefit from quantum speedups. ...

“In the public, the quantum computer was portrayed as if it would enable something not currently achievable, which is inaccurate,” he says. “Primarily, it will accelerate existing processes rather than introducing a completely disruptive new application area. So we are evaluating a difference here.” ... “Most problems in quantum chemistry do not scale exponentially, and approximations are sufficient,” he says. “They are well behaved problems, you just need to make them faster with increased system size.”

Compare to the hype surrounding Artificial Intelligence (AI). It is also over-hyped by its enthusiasts, but it has also delievered a lot of very impressive demonstrable results. Quantum computing has delivered nothing, and may never deliver anything.

Someday we really will have personal robots and self-driving cars, but we may never have a useful quantum computer.

Google Research just released a video:

Quantum Computing - Hype vs. reality | Field Notes

Google Research
35.7K subscribers

25,188 views Jan 22, 2024 #GoogleAI #GoogleResearch
As the race to build the world's first truly useful quantum computer intensifies, so too does the need for clear-eyed assessment. This Field Notes episode brings in the Google Quantum AI team to help answer a few fundamental questions to drive understanding of its impact now and in the future.

It says quantum computers could become useful by 2030, or maybe a few years later.

the group is called "Quantum AI", but the video said nothing about AI. Just combining buzzwords, I guess.

The most touted application was fusion simulations, in order to help bring fusion power plants to market. Othere were discuvering drugs, and making the planet greener with chemistry for better batteries and fertilizer.

No mention of breaking everyone's cryptosystems. That is the only think quantum computer enthusiasts are sure about.

I am amazed that Google keeps funding this pipe dream. It has canceled hundreds of really useful products. It has developed some really good AI, but is checken to market it like OpenAI and Microsoft. Elsewhere Google touts quantum machine learning, but I doubt this will ever be practical. The non-quantum methods are progressing rapidly, and there is no sign that quantum computers would be useful.

Self-driving cares are over-hyyped, but I believe we are making progress and will get there. I do not think that that we are getting any closer to quantum computing.

Friday, January 26, 2024

The Evidence for CO2 Global Warming

Sabine Hossenfelder posts:
How do we know climate change is caused by humans?

In this video I summarize the main pieces of evidence that we have which show that climate change is caused by humans. This is most important that we know in which frequency range carbon dioxide absorbs light, we know that the carbon dioxide ratio in the atmosphere has been increasing, we know that the Ph-value of the oceans has been decreasing, the ratio of carbon isotopes in the atmosphere has been changing, and the stratosphere has been cooling, which was one of the key predictions of climate models from the 1960s.

She says this info is hard to find, but I found the same info as the first link from a search, a 2009 artucke:
How Do We Know that Humans Are the Major Cause of Global Warming?
YouTube also slaps an obnoxious "context" link on the video, with some info. You also get the same info from ChatGPT.

The evidence is that humans burning fossil fuels emit CO2, and the increases in atmospheric CO2 have caused warming. Probably most of the warming observed in recent decades.

My quibble is when they leap from this to saying that humans cause most of the climate change. The climate is changing a lot of different ways, in different places. I do not see anyone even trying to quantify climate change. Just CO2 and temperature.

Monday, January 22, 2024

Albert Explains Flaws in Many-Worlds

Newly-released video:
David Albert - What Does Quantum Theory Mean?

Quantum theory may be weird—superposition and entanglement of particles that in our normal world would make no sense—but quantum theory is truly how the microworld works. What does all this weirdness mean? How to go from microworld weirdness to macroworld normalcy? Will we ever make sense out of quantum mechanics?

Albert is a physicist-turned-philosopher, and he explains this pretty well.

He goes on to say that more and more physicists are adopting the many-worlds interpretation. He says it is counter-intuitive, but does not reject it for that reason. He rejects it because it does not explain the world.

In his opinion, it does not really solve the measurement problem, for two reasons.

(1) it tries to explain the definite outcomes as an illusion. Maybe this position could be justified some day.

(2) it cannot explain the probabilities we see, as many-worlds says all outcomes are determined.

He admits that physicists have done a lot of contortions to try to get around these issues, but they have failed.

"At the end of the day, it does not account for our experience."

I agree with him on these points. Perhaps mathematical physicists will develop a decoherence theory showing that the wave function branching resembles what we see. It hasn't happened yet, but it is possible.

But many-worlds will never explain the probabilities, because the whole point of many-worlds is to reject probabilities. The parallel worlds arise because probabilities are interpreted as world splittings, and all possibilities are realized in inaccessible alternate worlds.

So why are more and more physicists adopting such a wrong theory? No answer given. Physicists are losing their grip on reality.