## Wednesday, August 28, 2019

### What makes people attracted to wrong theories?

LIGO/Virgo rumor (Quanta Magazine): black holes with the masses 50-130 Suns, often thought to be impossible due to some oxygen-turns-implosion-to-explosion reasons, were apparently detected. I would always bet that this gap should be non-existent, at most with a slightly lowered number of holes. To say the least, you may get larger black holes from smaller ones that keep on merging or eating, right?
Decoding the psychology of scientific populism and teachers' laziness

On Saturday, aside from many much more positive things, I also heard about the dissatisfaction of some teachers – and their students – about quantum mechanics and similar things and these exchanges were among the friendliest ones. So I really tried to figure out what's going on etc. OK, I will discuss two examples, both from Teacher J, but there were some other similar lessons.

First, Teacher J was excited about entropic gravity. Wouldn't it be cool etc.? So I could see the actual "happiness in the terrain" that made it possible for Erik Verlinde to receive some "tens of millions of dollars" for this idea that is a piece of crap not worth a penny.
It would be so cool because Verlinde would also explain the phenomena usually attributed to dark matter and dark energy without dark matter and dark energy.
Right, it would be attractive. If it were the case. So the simple reason why there was a driver for him to be rewarded for these wrong statements was the fact that he has given some promises to the laymen. He has explained or he would explain fundamental things in a simpler way without "new" concepts etc. Great.

The only problem is that it doesn't work at all. The second hyperlink after "gravity" in the entropic gravity article on Wikipedia is one to the entropic force whose very first sentence says that the entropic force is by definition associated with the system's drifting towards high-entropy states.

But by the second law of thermodynamics, the entropy cannot drift to lower values at all. So the tendency to move towards higher entropy leads to irreversible processes. Irreversibility is a general property of entropic forces. You may reverse some consequences of entropic forces but you need qualitatively different, additional forces to do so. However, planets with a large eccentricity "oscillate" between different distances from the Sun. The changes of the distance are going back and forth. So the gravitational attraction is clearly not an irreversible force, so it can't be an entropic force, either, because every entropic force is irreversible. QED.

One can really disprove the theory, and I have done so, within a minute. One is reversible, the other one is irreversible, so they can't be the same. But millions of dollars is a lot of money so I was unavoidably served lots of nonsense. Maybe entropic forces may be reversible. Maybe the gravitational phenomena are adiabatic so the entropy is approximately constant. Great. But if the entropy is approximately constant, then the force has to be equally approximately zero because the entropic forces are proportional to the changes (the gradient in a parameter space) of the entropy. So it's clear that there just isn't any loophole.

As argued independently by me and later Archil Kobakhidze, the entropic gravity is also ruled out by the proper "undergraduate QM-like" behavior of neutrons in a gravitational field, some interference caused by gravity. The description depends on the same "number of states" for each height of the neutron. The height-dependent entropy means a height-dependent number of relevant states so the predictions would have to disagree. QED.

Entropic gravity is really a silly claim that a good physicist may be fooled by at most for minutes. But it's the kind of wrong ideas that are driven to "survive for years" although now, a decade later, one could say that it's finally dead and doesn't excite anybody. It was attractive for the laymen because they were promised that notions such as "gravity", "dark matter", and "dark energy" could have been completely eliminated from physics and become emergent. The problem is that the impressed laymen don't really think critically and don't check the statements – whether these alternative explanations of all the phenomena actually work. If they were checking them, they would know that the answer is No.

While a great majority of the good physicists didn't touch "entropic gravity", not even through a thousand of condoms, we were obviously talking about the issue with many, e.g. Andy Strominger. The "entropic gravity" entry on Wikipedia quotes him as saying:
The paper drew a variety of responses from the scientific community. Andrew Strominger, a string theorist at Harvard said "Some people have said it can't be right, others that it's right and we already knew it — that it’s right and profound, right and trivial."
That's what he was saying. And it's a sociologically true and entertaining statement. You could hear all these appraisals about the entropic gravity. It was right but not new, we already knew it. It was clearly wrong (that's me). It was right and deep. It was right and shallow, and so on. Entertaining. Because the speech doesn't need any word bags, people can say everything and they do say everything if you have enough diversity. But the statements aren't created equal and science isn't comparative literature where the people are amused by trying to collect the most contradictory collection of diverse testimonies. Science isn't trying to maximize "diversity" for the sake of it, not even the "diversity of opinions". It's still true that what I say is backed by the valid evidence and what others say is not.

From the viewpoint of a mankind, a society, or a community that is unable to settle a simple and straightforward high-school-level question whether gravity is an entropic force, all papers ever written by Andy Strominger (or me or anyone) are obviously totally worthless because they're some 5 levels more abstract than the "undecidable" question and the number of the people who can settle these more abstract questions is some 5 orders of magnitude smaller than those who can settle the question whether gravity is an entropic force. Above a certain level of omnipresent stupidity of the "community", science as a collective activity becomes a totally meaningless waste of time. We already seem to be there.

Entropy is important in quantum gravity – especially in the black hole entropy that Andy knows a lot about – but the importance of entropy in quantum gravity doesn't mean that "every bold statement involving the words entropy and gravity is correct". Verlinde's was a rather specific bold statement, one may evaluate it, and the answer, as shown above, is that it is false. He's basically saying that there's some huge entropy comparable to a huge black hole entropy that is behind the orbiting of the Earth around the Sun. It just isn't the case. The entropy of that system is tiny relatively to any black hole. We know that from many sources.

OK, my first point was that the laymen are simply manipulated by promises that cannot be fulfilled, by recipes that don't work. And they want to reduce the number of fundamental notions in physics – just like good physicists generally want it – but they usually want it for different reasons (they really hate to learn new things in physics and every new thing is a pain). At this level, the mechanism is totally analogous to the supporters of politicians who promise things that can't be fulfilled. The bad step of the physicists promoting wrong theories is that they are snake oil salesman; and the mistake of the snake oil buyers is that they lack critical thinking and don't check their goods. It's this simple. But it's not the whole story.

Concerning the observer dependence of quantum mechanics, Teacher J would prepare the following scenario:
Imagine that all nuclear bombs are scheduled to be detonated. The first 1/2 of them is enough to kill all humans. Will the remaining 1/2 of the bombs detonate although there's no one to see it?
Of course, his conclusion was that the detonation of the rest must be real because the bombs were constructed to detonate – independently of whether there are humans around – so this will happen. By extension, all of physical phenomena are observer-independent. But are they?

Teacher J has attributed the argument to the curiosity of some of his students. Of course, I couldn't say whether the exchange has actually taken place, whether a student was thinking in the exact same way etc., or whether the kids were introduced as human shields ;-) to shield the possibly incorrect argumentation of the teacher himself from any criticism. Needless to say, I think that it doesn't really matter whether a student or a teacher says such a thing – both of them may be right or wrong and there's not much difference in the kids' and kids' teachers' misunderstandings of quantum mechanics.

Fine. So as you can understand, I felt uneasy that I was pushed towards defending some stupidly sounding claim about nuclear bombs. Nuclear bombs are big objects, their basic properties such as "detonated or not" evolve according to the laws of classical physics with a huge accuracy. This description is extremely close to being accurate and sufficient, it's the reasoning that we normally use to think about the detonation of bombs. So of course I would also normally say that the nuclear bombs will detonate independently of humans.

But quantum mechanics isn't primarily important for discussing explosions of big objects – for which classical physics is enough. It is primarily designed for the discussion of phenomena in which classical physics fails. The more classical physics fails, the more quantum mechanics is important, of course. So you know, I protested with a comment similar to:
It's a bit of a demagogy to talk about nuclear bombs because it's hard to identify the new quantum phenomena such as the quantum interference in between the macroscopically different states. By attributing a stupidly sounding claim about bombs to me, the student is just trying to mock me in his or her effort to avoid the learning of a new framework of physics, quantum mechanics.
It's not exactly how I formulated it and even this monologue isn't the most precise reaction that I would fine-tune if I were working on it as a perfectionist. But I am sure you get my point. The argumentation about such general philosophical issues unavoidably involves some extrapolation or generalization of our knowledge to new realms. And the problem is that some of these extrapolations are just wrong and "ad absurdum" proofs are simply demagogic.

The real problem with the whole talk about bombs (which is equivalent to the Moon without a mouse that looks at it, cheese, noise in a forest with a wind and without humans, and lots of examples of trivial classical "facts" that have been used as cocktail party arguments against quantum mechanics) is that bombs and moons are "special objects" in the sense that they are macroscopic so most of the intrinsically quantum phenomena are heavily masked by the fact that the classical approximation works damn well.

If the student were seriously trying to understand how quantum mechanics works and how its rules should be carefully phrased, he or she would discuss phenomena where the quantum behavior is strong enough to be detectable, where it matters. So it could be atoms or nuclei that decay, not nuclear bombs. And things would become very different because whether or not a radioactive nucleus has decayed really needs some observer – and one may write down more specific mathematics to defend this claim.

As you can understand, the discussion had some unavoidable "moral dimension". I was basically saying that the student – who was probably just a placeholder for the teacher himself LOL – was just trying to fool himself or herself and was demagogic in his or her fight against the unwelcome alternative conclusion. But Teacher J said:
But the student sincerely wants to know, he or she is honestly curious.
Is it true? That's a very subtle claim. When we discussed Darwin's theory with our creationist friends at the student hostels, were they also just honestly and sincerely telling us that they believed that Darwin has predicted that a bird on the tree suddenly becomes a squirrel? Is that really sincere or am I allowed to call it demagogy?

From my viewpoint, it's clearly a demagogy – both examples, one with bombs and one with the squirrel – because I understand why both evolution and quantum mechanics work. So evolution and quantum mechanics make certain predictions but these predictions don't include that "a bird suddenly becomes a squirrel while sitting on the tree" and not even "it is impossible to talk about the explosion of bombs in the absence of humans". The evolution is much slower and involves many generations of animals, not one, and quantum mechanics does imply that classical physics is a good approximation for large systems such as bombs which gives us some justification to use the classical language for those effects, too.

But yes, I can imagine that from a certain different viewpoint – one that is ignorant about certain things – the responses that look clearly demagogic to me may be "sincere". The creationists and the student critiquing the observer dependence of quantum mechanics are "just" picking examples for their thought experiments – they are extrapolating the rules that they were told to be valid and they are looking for the best extrapolation or an example in which the question may be settled. In some very general sense, it is a standard, clever, and valid procedure that scientists have to do as well.

After all, when I am saying that in principle, even the existence of an explosion has to be evaluated relatively to an observer, I am also extrapolating some conclusion that was actually verified in different situations only – in observations of much smaller systems where the quantum behavior is crucial.

As you can see, the problem is that some extrapolation is valid and some is not. In particular, the general qualitative laws working for a bunch of elementary particles may be extrapolated to larger and larger systems – basically because of reductionism (or at least the fact that it seems to be an unavoidable part of our laws of fundamental physics and nothing we have observed contradicts it). In principle, you need an observer who defines what is an observation and what is not in the case of one or two spin measurements; so in principle you need it if you want to describe atomic blasts really precisely, too.

On the other hand, the extrapolation of the conclusions made by the student goes in the opposite direction. The student (and Teacher J) wants to convince himself that the explosion of the nuclear bombs is observer-independent – and therefore, the same qualitative conclusion must hold for the molecules or electrons etc. All of physics is observer-independent, he concludes.

Do you get my point? The difference is that my extrapolation is correct because it's aligned with reductionism while his is incorrect because it goes against reductionism. He basically assumes that whatever he "derives" for large objects such as bombs must also work in general, including the world of elementary particles. But that's simply not the case because our statements about large and lazy objects are approximations (classical not quantum, non-relativistic not relativistic, thermodynamic not atomic-level statistical physics etc.). Approximations are mathematically limits – and when you know a limit (like the $$1/c\to 0$$ and $$\hbar\to 0$$ limit), you just can't say something about the behavior of the whole function outside the limit.

With this little bit careful analysis of "what is needed for an extrapolation to be valid", one may say that the student who uses the "objective bomb explosion" is only sincere if he is ignorant about reductionism – or at least unable to figure out what reductionism means for the correct implications between statements about large and small objects (you can deduce the behavior of the large from the laws for the small things but not vice versa). But if someone understands that the behavior of larger objects is basically reduced to the laws describing their elementary building blocks, then the fable about the last nuclear bombs is just a demagogy. It's a demagogy designed to fool not only others; it may be designed to fool the speaker – the teacher or the student – himself. And "one" is the simplest person to be fooled, as Feynman said.

By the way, there is an extra subtlety with the bombs. Even if you define any quantum mechanical observation whether the bombs have exploded, quantum mechanics simply predicts that the probability of the explosion in some conditions is extremely close to 100%. So the whole "magic" of quantum mechanics is really circumvented because we implicitly "demand" a post-human measurement whose outcome may be predicted almost with certainty, anyway. This is clearly a very special situation with extra "trivial" characteristics – which is why you obviously cannot generalize its conclusions in far-reaching ways, i.e. by saying that the fundamental laws should be observer-independent in general (in experiments where the measurement really intervenes and it matters; and whose outcomes are very uncertain).

Concerning the sincerity of the student, there is a pedagogical issue here because I was basically told:
Don't dare to correct the student or disagree with him or her. By constructing an argument against quantum mechanics, the student has shown something remarkable that we are obliged to nurture, his or her independent thinking, creativity, and blah blah blah.
At least this is what I read in between the sentences. Well, I beg to disagree. Nowadays, students are clearly encouraged to protest against everything – especially the things that are vital such as the pillars of the Western civilization (freedom of speech, fossil fuels etc.) – and there's not much valuable about these protests, especially when most students do it (while useful and "hard" things are done by almost nobody) and when all the proposed "fixes" coming from this overgrown protests seem to be deeply harmful for mankind.

It's simply right for a teacher to explain what's wrong with any argumentation by the student that is wrong. Even if the student is sincere and especially if he or she is sincere, he or she wants to hear responses to such arguments! And if he or she "doesn't want to hear them", he or she should still be exposed to them instead of being encouraged to live in "safe spaces". An issue is that it's not always easy for the teacher to actually know what the right response is. It's very convenient for the teacher to "believe" that his right job is not to respond and not to correct the student. With this assumption, the teacher doesn't have to know much and doesn't have to do much – and he still gets the salary. Who wouldn't like this postmodern setup in which the "mission" of the occupation has been obliterated? I wouldn't because this new type of namby-pamby teachers leads to the creation of arrogant yet uneducated and constantly whining students which contributes to the decay of the whole Western civilization. It is this approach – directly incorporated in the philosophy of Hejný's and other postmodern methods of teaching – that produces Gretas and similar diseases of our civilization.

So please, we surely don't need more of this stuff. We need far less of this stuff. Teachers have the duty to act as credible authorities of a sort. If they're namby-pamby people who just encourage the students in their arbitrarily unjustified whining, these teachers are just not performing their duties well.

And that's the memo.

P.S.: You have surely noticed that I haven't made a breathtakingly original discovery. Teachers are just passive – and that contributes to the growth of the Greta-like culture. But my more specific point is that there are many teachers who may agree us with in the pub, about the undesirability of the politically correct trends at schools and beyond the schools. But many of them have actually been brainwashed to believe that it's a good thing to indirectly encourage the Greta-like developments – by their passivity, submissiveness towards the students, and the glorification of any kind of an apparent "student protest".